/*
input子系统分析:
input.c
向下对驱动层提供的接口有:
input_allocate_device(); // 分配一个input device
input_event() // input_report_abs()内部调用input_event()
input_register_device(tpd->dev);
input_unregister_device(tpd->dev);
向上对事件处理层提供的接口:
input_register_handler() // 注册一个input handler
input_register_handle() // 注册一个input_handle结构(包含匹配后的dev与handler匹配)
=============================================
input 核心层: input.c 【注册流程】
static LIST_HEAD(input_dev_list); // 定义全局链表 : input device
static LIST_HEAD(input_handler_list); // 定义全局链表 : input handler
input_init() // subsys_initcall()
|
class_register(&input_class) // 将class注册到内核中，同时创建/sys/class/下节点，类似class_create()
input_proc_init() // 没啥用
|
proc_bus_input_dir = proc_mkdir("bus/input", NULL); // 创建文件夹"/proc/bus/input"
entry = proc_create("devices", 0, proc_bus_input_dir, &input_devices_fileops); // 创建节点"/proc/bus/input/devices"
entry = proc_create("handlers", 0, proc_bus_input_dir, &input_handlers_fileops);// 创建节点"/proc/bus/input/handlers"
register_chrdev_region(MKDEV(INPUT_MAJOR, 0), INPUT_MAX_CHAR_DEVICES, "input"); // 根据要求申请主设备号，主设备号INPUT_MAJOR == 13
=============================================
input handler层: evdev.c 【注册流程】
evdev_init() // module_init()
|
input_register_handler(&evdev_handler)
|
INIT_LIST_HEAD(&handler->h_list);
list_add_tail(&handler->node, &input_handler_list); // 重要，把input handler挂到全局的链表input_handler_list上
list_for_each_entry(dev, &input_dev_list, node) // 核心重点，遍历input_dev_list链表，链表中每一个input device均尝试与当前的input handler(evdev)匹配
input_attach_handler(dev, handler); // evdev可以与任何input device匹配，因为evdev的id_table[]为空
|
id = input_match_device(handler, dev); // 根据evdev的id_table[]进行匹配 - 满足id_table[]中的全部条件才能匹配成功
error = handler->connect(handler, dev, id); // 匹配成功后调用handler中connect() -- .connect = evdev_connect,
input_wakeup_procfs_readers(); // 将当前的handler加入到/proc/bus/input/handlers文件中
总结:
1. 注册了evdev_handler
2. 遍历input_dev_list，进行行匹配，匹配成功，调用handler中connect方法--- evdev_connect()
3. 内核有好几个input handler: evdev、mousedev、joydev、evbug等
4. 其中 evdev 可以处理所有的事件，触摸屏驱动，sensor就是用的这个。
=============================================
input 驱动层: accel.c 【注册流程】
acc_input_init(struct acc_context *cxt)
{
struct input_dev *dev;
int err = 0;
dev = input_allocate_device();
dev->name = ACC_INPUTDEV_NAME;
input_set_capability(dev, EV_ABS, EVENT_TYPE_ACCEL_X);
input_set_capability(dev, EV_ABS, EVENT_TYPE_ACCEL_Y);
input_set_capability(dev, EV_ABS, EVENT_TYPE_ACCEL_Z);
input_set_capability(dev, EV_ABS, EVENT_TYPE_ACCEL_STATUS);
input_set_capability(dev, EV_REL, EVENT_TYPE_ACCEL_UPDATE);
input_set_capability(dev, EV_REL, EVENT_TYPE_ACCEL_TIMESTAMP_HI);
input_set_capability(dev, EV_REL, EVENT_TYPE_ACCEL_TIMESTAMP_LO);
input_set_abs_params(dev, EVENT_TYPE_ACCEL_X, ACC_VALUE_MIN, ACC_VALUE_MAX, 0, 0);
input_set_abs_params(dev, EVENT_TYPE_ACCEL_Y, ACC_VALUE_MIN, ACC_VALUE_MAX, 0, 0);
input_set_abs_params(dev, EVENT_TYPE_ACCEL_Z, ACC_VALUE_MIN, ACC_VALUE_MAX, 0, 0);
input_set_abs_params(dev, EVENT_TYPE_ACCEL_STATUS, ACC_STATUS_MIN, ACC_STATUS_MAX, 0, 0);
input_set_drvdata(dev, cxt);
input_register_device(dev);
}
input_register_device(dev)
|
list_add_tail(&dev->node, &input_dev_list); // 重要，把input device挂到全局的链表input_dev_list上
list_for_each_entry(handler, &input_handler_list, node) // 核心重点，遍历input_handler_list链表，链表中每一个input handler均尝试与当前的input device匹配
input_attach_handler(dev, handler); // evdev可以与任何input device匹配，因为evdev的id_table[]为空
|
id = input_match_device(handler, dev); // 根据evdev的id_table[]进行匹配 - 满足id_table[]中的全部条件才能匹配成功
error = handler->connect(handler, dev, id); // 匹配成功后调用handler中connect() -- .connect = evdev_connect,
static struct input_handler evdev_handler = {
.event = evdev_event,
.events = evdev_events,
.connect = evdev_connect,
.disconnect = evdev_disconnect,
.legacy_minors = true,
.minor = EVDEV_MINOR_BASE,
.name = "evdev",
.id_table = evdev_ids,
};
====
等待队列的实现:
1 wait_queue_head_t mywq_head;
2 init_waitqueue_head(&mywq_head);
3 wait_event_interruptible( mywq_head, fs210_btn_device->btn_state); // 条件不满足，就把调用进程挂起
4 wake_up_interruptible(&mywq_head); // 唤醒等待队列 - 等待队列需要显式唤醒
====
evdev_connect(struct input_handler *handler, struct input_dev *dev, const struct input_device_id *id)
|
minor = input_get_new_minor(EVDEV_MINOR_BASE, EVDEV_MINORS, true); // 分配次设备号，找到一个尚未被使用的最小次设备号，从64开始，65，66
evdev = kzalloc(sizeof(struct evdev), GFP_KERNEL); // 实例化一个evdev对象
INIT_LIST_HEAD(&evdev->client_list); // 多个应用打开同一个input device时，每次open都生成一个clinet，挂载到client_list，数据上报时遍历链表，copy到所有成员的buffer中
init_waitqueue_head(&evdev->wait); // 等待队列用于完成阻塞，read()的时候，没数据(缓存队列头等于尾)就睡眠，唤醒条件为有数据(缓存队列头不等于尾)，input_sync()显示唤醒
dev_set_name(&evdev->dev, "event%d", dev_no); // 创建设备文件/dev/input/event0/1/2 以下代码与device_create()一样
evdev->dev.devt = MKDEV(INPUT_MAJOR, minor);
evdev->dev.class = &input_class;
evdev->dev.parent = &dev->dev;
evdev->dev.release = evdev_free;
device_initialize(&evdev->dev);
evdev->handle.dev = input_get_device(dev); // 利用handle记录input device和input handler(经过匹配后的)
evdev->handle.handler = handler;
evdev->handle.private = evdev; // 后面evdev_events(struct input_handle *handle,)根据handle 拿到evdev
input_register_handle(&evdev->handle);
|
list_add_tail_rcu(&handle->d_node, &dev->h_list); // 将handle与input device关联，互相可以找到
list_add_tail_rcu(&handle->h_node, &handler->h_list); // 将handle与input handler关联，互相可以找到
cdev_init(&evdev->cdev, &evdev_fops); // 初始化并注册字符设备cdev，完成fops，为用户提供文件io接口
cdev_add(&evdev->cdev, evdev->dev.devt, 1);
总结:
1. 分配evdev，并初始化，记录handle 与 input device、input handler的关系
2. 创建设备节点/dev/input/event0/1/2
3. 注册cdev，并实现fops
4. 关系:
多个input device可以对应一个input handler
一个input device对应一个evdev，对应一个设备节点:/dev/input/event0/1/2
一个input device可以被多个应用打开，每次打开生成一个clinet，挂载到evdev中的client_list链表
5. 所有设备节点被调用open(),read(),write()文件io的时候
实际上都是调用cdev中fops的各个接口:
static const struct file_operations evdev_fops = {
.owner = THIS_MODULE,
.read = evdev_read,
.write = evdev_write,
.poll = evdev_poll,
.open = evdev_open,
...
};
device_create()
device_create_vargs(class, parent, devt, drvdata, fmt, vargs);
device_create_groups_vargs(class, parent, devt, drvdata, NULL, fmt, args);
struct device *dev = NULL;
dev = kzalloc(sizeof(*dev), GFP_KERNEL);
device_initialize(dev);
dev->devt = devt;
dev->class = class;
dev->parent = parent;
dev->groups = groups;
dev->release = device_create_release;
dev_set_drvdata(dev, drvdata);
retval = kobject_set_name_vargs(&dev->kobj, fmt, args); // 设置名字
retval = device_add(dev); // 注册到系统
==============================================
1. 应用程序调用open()
以androidM Gsensor为例
hal层中acceleration.cpp中
FindDataFd()
fd = open("/sys/class/misc/m_acc_misc/accdevnum", O_RDONLY);
len = read(fd, buf, sizeof(buf)-1);
buf[len] = '
/*
input子系统分析:
input.c
向下对驱动层提供的接口有:
input_allocate_device(); // 分配一个input device
input_event() // input_report_abs()内部调用input_event()
input_register_device(tpd->dev);
input_unregister_device(tpd->dev);
向上对事件处理层提供的接口:
input_register_handler() // 注册一个input handler
input_register_handle() // 注册一个input_handle结构(包含匹配后的dev与handler匹配)
=============================================
input 核心层: input.c 【注册流程】
static LIST_HEAD(input_dev_list); // 定义全局链表 : input device
static LIST_HEAD(input_handler_list); // 定义全局链表 : input handler
input_init() // subsys_initcall()
|
class_register(&input_class) // 将class注册到内核中，同时创建/sys/class/下节点，类似class_create()
input_proc_init() // 没啥用
|
proc_bus_input_dir = proc_mkdir("bus/input", NULL); // 创建文件夹"/proc/bus/input"
entry = proc_create("devices", 0, proc_bus_input_dir, &input_devices_fileops); // 创建节点"/proc/bus/input/devices"
entry = proc_create("handlers", 0, proc_bus_input_dir, &input_handlers_fileops);// 创建节点"/proc/bus/input/handlers"
register_chrdev_region(MKDEV(INPUT_MAJOR, 0), INPUT_MAX_CHAR_DEVICES, "input"); // 根据要求申请主设备号，主设备号INPUT_MAJOR == 13
=============================================
input handler层: evdev.c 【注册流程】
evdev_init() // module_init()
|
input_register_handler(&evdev_handler)
|
INIT_LIST_HEAD(&handler->h_list);
list_add_tail(&handler->node, &input_handler_list); // 重要，把input handler挂到全局的链表input_handler_list上
list_for_each_entry(dev, &input_dev_list, node) // 核心重点，遍历input_dev_list链表，链表中每一个input device均尝试与当前的input handler(evdev)匹配
input_attach_handler(dev, handler); // evdev可以与任何input device匹配，因为evdev的id_table[]为空
|
id = input_match_device(handler, dev); // 根据evdev的id_table[]进行匹配 - 满足id_table[]中的全部条件才能匹配成功
error = handler->connect(handler, dev, id); // 匹配成功后调用handler中connect() -- .connect = evdev_connect,
input_wakeup_procfs_readers(); // 将当前的handler加入到/proc/bus/input/handlers文件中
总结:
1. 注册了evdev_handler
2. 遍历input_dev_list，进行行匹配，匹配成功，调用handler中connect方法--- evdev_connect()
3. 内核有好几个input handler: evdev、mousedev、joydev、evbug等
4. 其中 evdev 可以处理所有的事件，触摸屏驱动，sensor就是用的这个。
=============================================
input 驱动层: accel.c 【注册流程】
acc_input_init(struct acc_context *cxt)
{
struct input_dev *dev;
int err = 0;
dev = input_allocate_device();
dev->name = ACC_INPUTDEV_NAME;
input_set_capability(dev, EV_ABS, EVENT_TYPE_ACCEL_X);
input_set_capability(dev, EV_ABS, EVENT_TYPE_ACCEL_Y);
input_set_capability(dev, EV_ABS, EVENT_TYPE_ACCEL_Z);
input_set_capability(dev, EV_ABS, EVENT_TYPE_ACCEL_STATUS);
input_set_capability(dev, EV_REL, EVENT_TYPE_ACCEL_UPDATE);
input_set_capability(dev, EV_REL, EVENT_TYPE_ACCEL_TIMESTAMP_HI);
input_set_capability(dev, EV_REL, EVENT_TYPE_ACCEL_TIMESTAMP_LO);
input_set_abs_params(dev, EVENT_TYPE_ACCEL_X, ACC_VALUE_MIN, ACC_VALUE_MAX, 0, 0);
input_set_abs_params(dev, EVENT_TYPE_ACCEL_Y, ACC_VALUE_MIN, ACC_VALUE_MAX, 0, 0);
input_set_abs_params(dev, EVENT_TYPE_ACCEL_Z, ACC_VALUE_MIN, ACC_VALUE_MAX, 0, 0);
input_set_abs_params(dev, EVENT_TYPE_ACCEL_STATUS, ACC_STATUS_MIN, ACC_STATUS_MAX, 0, 0);
input_set_drvdata(dev, cxt);
input_register_device(dev);
}
input_register_device(dev)
|
list_add_tail(&dev->node, &input_dev_list); // 重要，把input device挂到全局的链表input_dev_list上
list_for_each_entry(handler, &input_handler_list, node) // 核心重点，遍历input_handler_list链表，链表中每一个input handler均尝试与当前的input device匹配
input_attach_handler(dev, handler); // evdev可以与任何input device匹配，因为evdev的id_table[]为空
|
id = input_match_device(handler, dev); // 根据evdev的id_table[]进行匹配 - 满足id_table[]中的全部条件才能匹配成功
error = handler->connect(handler, dev, id); // 匹配成功后调用handler中connect() -- .connect = evdev_connect,
static struct input_handler evdev_handler = {
.event = evdev_event,
.events = evdev_events,
.connect = evdev_connect,
.disconnect = evdev_disconnect,
.legacy_minors = true,
.minor = EVDEV_MINOR_BASE,
.name = "evdev",
.id_table = evdev_ids,
};
====
等待队列的实现:
1 wait_queue_head_t mywq_head;
2 init_waitqueue_head(&mywq_head);
3 wait_event_interruptible( mywq_head, fs210_btn_device->btn_state); // 条件不满足，就把调用进程挂起
4 wake_up_interruptible(&mywq_head); // 唤醒等待队列 - 等待队列需要显式唤醒
====
evdev_connect(struct input_handler *handler, struct input_dev *dev, const struct input_device_id *id)
|
minor = input_get_new_minor(EVDEV_MINOR_BASE, EVDEV_MINORS, true); // 分配次设备号，找到一个尚未被使用的最小次设备号，从64开始，65，66
evdev = kzalloc(sizeof(struct evdev), GFP_KERNEL); // 实例化一个evdev对象
INIT_LIST_HEAD(&evdev->client_list); // 多个应用打开同一个input device时，每次open都生成一个clinet，挂载到client_list，数据上报时遍历链表，copy到所有成员的buffer中
init_waitqueue_head(&evdev->wait); // 等待队列用于完成阻塞，read()的时候，没数据(缓存队列头等于尾)就睡眠，唤醒条件为有数据(缓存队列头不等于尾)，input_sync()显示唤醒
dev_set_name(&evdev->dev, "event%d", dev_no); // 创建设备文件/dev/input/event0/1/2 以下代码与device_create()一样
evdev->dev.devt = MKDEV(INPUT_MAJOR, minor);
evdev->dev.class = &input_class;
evdev->dev.parent = &dev->dev;
evdev->dev.release = evdev_free;
device_initialize(&evdev->dev);
evdev->handle.dev = input_get_device(dev); // 利用handle记录input device和input handler(经过匹配后的)
evdev->handle.handler = handler;
evdev->handle.private = evdev; // 后面evdev_events(struct input_handle *handle,)根据handle 拿到evdev
input_register_handle(&evdev->handle);
|
list_add_tail_rcu(&handle->d_node, &dev->h_list); // 将handle与input device关联，互相可以找到
list_add_tail_rcu(&handle->h_node, &handler->h_list); // 将handle与input handler关联，互相可以找到
cdev_init(&evdev->cdev, &evdev_fops); // 初始化并注册字符设备cdev，完成fops，为用户提供文件io接口
cdev_add(&evdev->cdev, evdev->dev.devt, 1);
总结:
1. 分配evdev，并初始化，记录handle 与 input device、input handler的关系
2. 创建设备节点/dev/input/event0/1/2
3. 注册cdev，并实现fops
4. 关系:
多个input device可以对应一个input handler
一个input device对应一个evdev，对应一个设备节点:/dev/input/event0/1/2
一个input device可以被多个应用打开，每次打开生成一个clinet，挂载到evdev中的client_list链表
5. 所有设备节点被调用open(),read(),write()文件io的时候
实际上都是调用cdev中fops的各个接口:
static const struct file_operations evdev_fops = {
.owner = THIS_MODULE,
.read = evdev_read,
.write = evdev_write,
.poll = evdev_poll,
.open = evdev_open,
...
};
device_create()
device_create_vargs(class, parent, devt, drvdata, fmt, vargs);
device_create_groups_vargs(class, parent, devt, drvdata, NULL, fmt, args);
struct device *dev = NULL;
dev = kzalloc(sizeof(*dev), GFP_KERNEL);
device_initialize(dev);
dev->devt = devt;
dev->class = class;
dev->parent = parent;
dev->groups = groups;
dev->release = device_create_release;
dev_set_drvdata(dev, drvdata);
retval = kobject_set_name_vargs(&dev->kobj, fmt, args); // 设置名字
retval = device_add(dev); // 注册到系统
==============================================
1. 应用程序调用open()
以androidM Gsensor为例
hal层中acceleration.cpp中
FindDataFd()
fd = open("/sys/class/misc/m_acc_misc/accdevnum", O_RDONLY);
len = read(fd, buf, sizeof(buf)-1);
buf[len] = '\0';
sscanf(buf, "%d\n", &num);
sprintf(buf_s, "/dev/input/event%d", num);
fd = open(buf_s, O_RDONLY);
readEvents()
mInputReader.fill(mdata_fd)
mInputReader.readEvent(&event)
即open("/dev/input/event%d", O_RDONLY);
-----------------------------------------
vfs
sys_open(); // 系统调用
struct file file->f_ops = cdev->ops;
file->f_ops->open();
-----------------------------------------
input handler层: evdev.c
cdev
xxx_ops = {
.open = xxx_open,
.read = xxx_read,
}
evdev_connect()
cdev_init(&evdev->cdev, &evdev_fops);
static const struct file_operations evdev_fops = {
.owner = THIS_MODULE,
.read = evdev_read,
.write = evdev_write,
.poll = evdev_poll,
.open = evdev_open,
};
实际上最终调用了evdev_open()
evdev_open(struct inode *inode, struct file *file)
|
struct evdev *evdev = container_of(inode->i_cdev, struct evdev, cdev); // 以小博大，inode->i_cdev就是connect()中住的的cdev
unsigned int bufsize = evdev_compute_buffer_size(evdev->handle.dev); // 通过handle找到 input device，根据input device 获取缓冲区的大小(几个input event)，但是我们驱动中未给定缓冲区大小，系统会自动给定一个
unsigned int size = sizeof(struct evdev_client) + // size包含了很多个input event
bufsize * sizeof(struct input_event);
struct evdev_client *client;
client = kzalloc(size, GFP_KERNEL | __GFP_NOWARN); // 分配一个client对象，用来描述一个缓冲队列，存放的就是input_event
client->bufsize = bufsize; // client中有一个缓冲区
spin_lock_init(&client->buffer_lock);
client->evdev = evdev; // evdev_client中记录evdev
evdev_attach_client(evdev, client); // 将client 加入到evdev中的一个小链表中
|
list_add_tail_rcu(&client->node, &evdev->client_list);
file->private_data = client; // evdev_client记录到file中，方便其他接口调用(这里是open()，其他接口还有read()、write())
总结:
1. 为输入设备分配一个缓冲区evdev_client，用于存放input device层上报的数据
2. evdev_client中记录evdev
3. evdev_client记录到file中，方便其他read() write() 等接口使用
==============================================
2.应用程序调用read()
read(fd, &event, sizeof(struct input_event));
-----------------------------------------
vfs
sys_read(); // 系统调用
file->f_ops->read(); // fd就是file数组的下表，通过传入的fd找到file，其中的f_ops在open()的时候已经获取并保存
-----------------------------------------
static ssize_t evdev_read(struct file *file, char __user *buffer, size_t count, loff_t *ppos)
|
struct evdev_client *client = file->private_data; // 获取open() 分配的缓冲区
struct evdev *evdev = client->evdev; // 获取到evdev
struct input_event event; // 表示一个数据包，要给用户
for (;;) {
// 实现非阻塞 -- 队列为空，且为非阻塞模式，直接返回again
if (client->packet_head == client->tail && // 队列的头跟尾位置一样 == 队列为空
(file->f_flags & O_NONBLOCK)) // 非阻塞
return -EAGAIN;
// while每循环一次取一个input event数据，read加1
while (read + input_event_size() <= count && // 这里判断要取的数据个数是否已取ok，count是要取得数据个数
evdev_fetch_next_event(client, &event)) { // 1. 从client的缓冲区取数据，放到event中
|
*event = client->buffer[client->tail++];// 将client->buffer[]队列的尾巴给*event
if (input_event_to_user(buffer + read, &event)) // 2. 把数据给用户空间
|
copy_from_user(event, buffer, sizeof(struct input_event))
read += input_event_size(); // 3. 统计上报多少数据
}
if (!(file->f_flags & O_NONBLOCK)) { // 如果当前不是非阻塞模式，即阻塞模式
error = wait_event_interruptible(evdev->wait, // 休眠 - 条件不满足就睡眠:
client->packet_head != client->tail || // 队列头不等于尾 -> 有数据
!evdev->exist || client->revoked);
总结:
1. 如果没数据，就休眠等待
2. 如果有数据，就会从缓冲区client->buffer[client->tail++]拿数据，通过copy_to_user上报给用户
疑问:
1. 数据到底是如何存放在缓冲区的
2. 等待队列是谁唤醒的
==============================================
3. 上报流程:
input_report_abs(gt811_dev->input, ABS_MT_POSITION_X, x);
input_report_abs(gt811_dev->input, ABS_MT_POSITION_Y, y);
input_mt_sync(gt811_dev->input);
input_report_abs(struct input_dev *dev, unsigned int code, int value)
|
input_event(dev, EV_ABS, code, value);
|
input_handle_event(dev, type, code, value);
|
if (disposition & INPUT_PASS_TO_HANDLERS) { // input device数据交给input handler处理
struct input_value *v;
v = &dev->vals[dev->num_vals++]; // 将input device获取到的数据暂存到dev->vals
v->type = type;
v->code = code;
v->value = value;
input_pass_values(dev, dev->vals, dev->num_vals);
|
list_for_each_entry_rcu(handle, &dev->h_list, d_node) // 通过inpit device中与handle建立连接的 h_list 成员找到 handle
if (handle->open)
input_to_handler(handle, vals, count);
|
struct input_handler *handler = handle->handler; // 通过出入的handle找到input handler(这里是evdev)
if (handler->events) // 首选events()， 没有才调用event()
handler->events(handle, vals, count); // 调用events()
else if (handler->event)
for (v = vals; v != end; v++)
handler->event(handle, v->type, v->code, v->value);
static struct input_handler evdev_handler = {
.event = evdev_event,
.events = evdev_events,
.connect = evdev_connect,
.disconnect = evdev_disconnect,
.legacy_minors = true,
.minor = EVDEV_MINOR_BASE,
.name = "evdev",
.id_table = evdev_ids,
};
static void evdev_events(struct input_handle *handle, const struct input_value *vals, unsigned int count)
|
struct evdev *evdev = handle->private; // 从handle中拿到evdev -- connect()中保存了:evdev->handle.private = evdev;
struct evdev_client *client;
如果多个应用进程打开了同一个input device, 每次open()都会生成一个evdev_client
evdev_client挂载到evdev的client_list链表中
input_report_abs()时，handler会把数据copy到client_list所有的evdev_client的buffer中
input_mt_sync()，逐一唤醒
list_for_each_entry_rcu(client, &evdev->client_list, node)
evdev_pass_values(client, vals, count, time_mono, time_real);
|
struct evdev *evdev = client->evdev; // 通过client 获取到 evdev
const struct input_value *v;
struct input_event event; // 数据包
event.time = ktime_to_timeval(client->clkid == CLOCK_MONOTONIC ? mono : real); // 填充数据包中的时间戳
for (v = vals; v != vals + count; v++) { // 将input device上报的数据封装成 input_event对象
event.type = v->type;
event.code = v->code;
event.value = v->value;
__pass_event(client, &event); // 将input event数据放在缓冲区的头部 -- 读的时候从尾巴开始读
|
client->buffer[client->head++] = *event; // 将input event数据放入缓冲区
client->head &= client->bufsize - 1;
if (v->type == EV_SYN && v->code == SYN_REPORT) // 唤醒等待队列 -- 如果调用了input_sync() -- input_event(dev, EV_SYN, SYN_REPORT, 0);
wakeup = true;
}
if (wakeup) // 唤醒等待队列
wake_up_interruptible(&evdev->wait);
struct input_event {
struct timeval time;
__u16 type; // 如:EV_ABS
__u16 code; // 如:ABS_MT_POSITION_X
__s32 value; // 如:x (具体的数值，这里是tp横坐标)
};
总结:
1. 数据到底是如何存放在缓冲区的
input_report_abs()将数据交给handler，调用events()，将数据放入缓冲区client->buffer[client->head++] = *event;
2. 等待队列是谁唤醒的
input_mt_sync() 显式唤醒等待队列 wake_up_interruptible(&evdev->wait);
*/
/*
字符设备注册流程
register_chrdev_region(MKDEV(major, 0), 1, "hello");
cdev_init(&hello_cdev, &hello_fops);
cdev_add(&hello_cdev, devid, 1);
cls = class_create(THIS_MODULE, "hello"); // 等同class_register()
dev = device_create(cls, NULL, MKDEV(major, 0), NULL, "hello")
*/
#define pr_fmt(fmt) KBUILD_BASENAME ": " fmt
#include <linux/init.h>
#include <linux/types.h>
#include <linux/idr.h>
#include <linux/input/mt.h>
#include <linux/module.h>
#include <linux/slab.h>
#include <linux/random.h>
#include <linux/major.h>
#include <linux/proc_fs.h>
#include <linux/sched.h>
#include <linux/seq_file.h>
#include <linux/poll.h>
#include <linux/device.h>
#include <linux/mutex.h>
#include <linux/rcupdate.h>
#include "input-compat.h"
MODULE_AUTHOR("Vojtech Pavlik <[email protected]>");
MODULE_DESCRIPTION("Input core");
MODULE_LICENSE("GPL");
#define INPUT_MAX_CHAR_DEVICES 1024
#define INPUT_FIRST_DYNAMIC_DEV 256
static DEFINE_IDA(input_ida);
static LIST_HEAD(input_dev_list);
static LIST_HEAD(input_handler_list);
/*
* input_mutex protects access to both input_dev_list and input_handler_list.
* This also causes input_[un]register_device and input_[un]register_handler
* be mutually exclusive which simplifies locking in drivers implementing
* input handlers.
*/
static DEFINE_MUTEX(input_mutex);
static const struct input_value input_value_sync = { EV_SYN, SYN_REPORT, 1 };
static inline int is_event_supported(unsigned int code,
unsigned long *bm, unsigned int max)
{
return code <= max && test_bit(code, bm);
}
static int input_defuzz_abs_event(int value, int old_val, int fuzz)
{
if (fuzz) {
if (value > old_val - fuzz / 2 && value < old_val + fuzz / 2)
return old_val;
if (value > old_val - fuzz && value < old_val + fuzz)
return (old_val * 3 + value) / 4;
if (value > old_val - fuzz * 2 && value < old_val + fuzz * 2)
return (old_val + value) / 2;
}
return value;
}
static void input_start_autorepeat(struct input_dev *dev, int code)
{
if (test_bit(EV_REP, dev->evbit) &&
dev->rep[REP_PERIOD] && dev->rep[REP_DELAY] &&
dev->timer.data) {
dev->repeat_key = code;
mod_timer(&dev->timer,
jiffies + msecs_to_jiffies(dev->rep[REP_DELAY]));
}
}
static void input_stop_autorepeat(struct input_dev *dev)
{
del_timer(&dev->timer);
}
/*
* Pass event first through all filters and then, if event has not been
* filtered out, through all open handles. This function is called with
* dev->event_lock held and interrupts disabled.
*/
static unsigned int input_to_handler(struct input_handle *handle,
struct input_value *vals, unsigned int count)
{
// 通过handle找到handler
struct input_handler *handler = handle->handler;
struct input_value *end = vals;
struct input_value *v;
for (v = vals; v != vals + count; v++) {
if (handler->filter && // 如果有过滤器，运行过滤，事实上没有
handler->filter(handle, v->type, v->code, v->value))
continue;
if (end != v)
*end = *v;
end++;
}
count = end - vals;
if (!count)
return 0;
// 调用events() 或 event() -- 数据暂存vals
if (handler->events)
handler->events(handle, vals, count); // 首选events()， 没有才调用event()
else if (handler->event)
for (v = vals; v != end; v++)
handler->event(handle, v->type, v->code, v->value);
return count;
}
/*
* Pass values first through all filters and then, if event has not been
* filtered out, through all open handles. This function is called with
* dev->event_lock held and interrupts disabled.
*/
static void input_pass_values(struct input_dev *dev,
struct input_value *vals, unsigned int count) // 数据暂存在vals
{
struct input_handle *handle;
struct input_value *v;
if (!count)
return;
rcu_read_lock();
// 从input device中获取到input handle
handle = rcu_dereference(dev->grab);
if (handle) {
count = input_to_handler(handle, vals, count);
}
// 走这里
else {
list_for_each_entry_rcu(handle, &dev->h_list, d_node)
if (handle->open)
count = input_to_handler(handle, vals, count);
}
rcu_read_unlock();
add_input_randomness(vals->type, vals->code, vals->value);
/* trigger auto repeat for key events */
for (v = vals; v != vals + count; v++) {
if (v->type == EV_KEY && v->value != 2) {
if (v->value)
input_start_autorepeat(dev, v->code);
else
input_stop_autorepeat(dev);
}
}
}
static void input_pass_event(struct input_dev *dev,
unsigned int type, unsigned int code, int value)
{
struct input_value vals[] = { { type, code, value } };
input_pass_values(dev, vals, ARRAY_SIZE(vals));
}
/*
* Generate software autorepeat event. Note that we take
* dev->event_lock here to avoid racing with input_event
* which may cause keys get "stuck".
*/
static void input_repeat_key(unsigned long data)
{
struct input_dev *dev = (void *) data;
unsigned long flags;
spin_lock_irqsave(&dev->event_lock, flags);
if (test_bit(dev->repeat_key, dev->key) &&
is_event_supported(dev->repeat_key, dev->keybit, KEY_MAX)) {
struct input_value vals[] = {
{ EV_KEY, dev->repeat_key, 2 },
input_value_sync
};
input_pass_values(dev, vals, ARRAY_SIZE(vals));
if (dev->rep[REP_PERIOD])
mod_timer(&dev->timer, jiffies +
msecs_to_jiffies(dev->rep[REP_PERIOD]));
}
spin_unlock_irqrestore(&dev->event_lock, flags);
}
#define INPUT_IGNORE_EVENT 0
#define INPUT_PASS_TO_HANDLERS 1
#define INPUT_PASS_TO_DEVICE 2
#define INPUT_SLOT 4
#define INPUT_FLUSH 8
#define INPUT_PASS_TO_ALL (INPUT_PASS_TO_HANDLERS | INPUT_PASS_TO_DEVICE)
static int input_handle_abs_event(struct input_dev *dev,
unsigned int code, int *pval)
{
struct input_mt *mt = dev->mt;
bool is_mt_event;
int *pold;
if (code == ABS_MT_SLOT) {
/*
* "Stage" the event; we'll flush it later, when we
* get actual touch data.
*/
if (mt && *pval >= 0 && *pval < mt->num_slots)
mt->slot = *pval;
return INPUT_IGNORE_EVENT;
}
is_mt_event = input_is_mt_value(code);
if (!is_mt_event) {
pold = &dev->absinfo[code].value;
} else if (mt) {
pold = &mt->slots[mt->slot].abs[code - ABS_MT_FIRST];
} else {
/*
* Bypass filtering for multi-touch events when
* not employing slots.
*/
pold = NULL;
}
if (pold) {
*pval = input_defuzz_abs_event(*pval, *pold,
dev->absinfo[code].fuzz);
if (*pold == *pval)
return INPUT_IGNORE_EVENT;
*pold = *pval;
}
/* Flush pending "slot" event */
if (is_mt_event && mt && mt->slot != input_abs_get_val(dev, ABS_MT_SLOT)) {
input_abs_set_val(dev, ABS_MT_SLOT, mt->slot);
return INPUT_PASS_TO_HANDLERS | INPUT_SLOT;
}
return INPUT_PASS_TO_HANDLERS;
}
static int input_get_disposition(struct input_dev *dev,
unsigned int type, unsigned int code, int *pval)
{
int disposition = INPUT_IGNORE_EVENT;
int value = *pval;
switch (type) {
case EV_SYN:
switch (code) {
case SYN_CONFIG:
disposition = INPUT_PASS_TO_ALL;
break;
case SYN_REPORT:
disposition = INPUT_PASS_TO_HANDLERS | INPUT_FLUSH;
break;
case SYN_MT_REPORT:
disposition = INPUT_PASS_TO_HANDLERS;
break;
}
break;
case EV_KEY:
if (is_event_supported(code, dev->keybit, KEY_MAX)) {
/* auto-repeat bypasses state updates */
if (value == 2) {
disposition = INPUT_PASS_TO_HANDLERS;
break;
}
if (!!test_bit(code, dev->key) != !!value) {
__change_bit(code, dev->key);
disposition = INPUT_PASS_TO_HANDLERS;
}
}
break;
case EV_SW:
if (is_event_supported(code, dev->swbit, SW_MAX) &&
!!test_bit(code, dev->sw) != !!value) {
__change_bit(code, dev->sw);
disposition = INPUT_PASS_TO_HANDLERS;
}
break;
case EV_ABS:
if (is_event_supported(code, dev->absbit, ABS_MAX))
disposition = input_handle_abs_event(dev, code, &value);
break;
case EV_REL:
if (is_event_supported(code, dev->relbit, REL_MAX) && value)
disposition = INPUT_PASS_TO_HANDLERS;
break;
case EV_MSC:
if (is_event_supported(code, dev->mscbit, MSC_MAX))
disposition = INPUT_PASS_TO_ALL;
break;
case EV_LED:
if (is_event_supported(code, dev->ledbit, LED_MAX) &&
!!test_bit(code, dev->led) != !!value) {
__change_bit(code, dev->led);
disposition = INPUT_PASS_TO_ALL;
}
break;
case EV_SND:
if (is_event_supported(code, dev->sndbit, SND_MAX)) {
if (!!test_bit(code, dev->snd) != !!value)
__change_bit(code, dev->snd);
disposition = INPUT_PASS_TO_ALL;
}
break;
case EV_REP:
if (code <= REP_MAX && value >= 0 && dev->rep[code] != value) {
dev->rep[code] = value;
disposition = INPUT_PASS_TO_ALL;
}
break;
case EV_FF:
if (value >= 0)
disposition = INPUT_PASS_TO_ALL;
break;
case EV_PWR:
disposition = INPUT_PASS_TO_ALL;
break;
}
*pval = value;
return disposition;
}
static void input_handle_event(struct input_dev *dev,
unsigned int type, unsigned int code, int value)
{
int disposition;
disposition = input_get_disposition(dev, type, code, &value);
if ((disposition & INPUT_PASS_TO_DEVICE) && dev->event) // 【少用】input device数据交给自己的evdev处理，且有自己的evdev，调用自己的evdev处理
dev->event(dev, type, code, value);
if (!dev->vals)
return;
if (disposition & INPUT_PASS_TO_HANDLERS) { // input device数据交给input handler处理
struct input_value *v;
if (disposition & INPUT_SLOT) {
v = &dev->vals[dev->num_vals++];
v->type = EV_ABS;
v->code = ABS_MT_SLOT;
v->value = dev->mt->slot;
}
// 将input device获取到的数据暂存到dev->vals
v = &dev->vals[dev->num_vals++];
v->type = type;
v->code = code;
v->value = value;
}
if (disposition & INPUT_FLUSH) {
if (dev->num_vals >= 2)
input_pass_values(dev, dev->vals, dev->num_vals);
dev->num_vals = 0;
} else if (dev->num_vals >= dev->max_vals - 2) {
dev->vals[dev->num_vals++] = input_value_sync;
input_pass_values(dev, dev->vals, dev->num_vals);
dev->num_vals = 0;
}
}
/**
* input_event() - report new input event
* @dev: device that generated the event
* @type: type of the event
* @code: event code
* @value: value of the event
*
* This function should be used by drivers implementing various input
* devices to report input events. See also input_inject_event().
*
* NOTE: input_event() may be safely used right after input device was
* allocated with input_allocate_device(), even before it is registered
* with input_register_device(), but the event will not reach any of the
* input handlers. Such early invocation of input_event() may be used
* to 'seed' initial state of a switch or initial position of absolute
* axis, etc.
*/
void input_event(struct input_dev *dev,
unsigned int type, unsigned int code, int value)
{
unsigned long flags;
if (is_event_supported(type, dev->evbit, EV_MAX)) { // type : EV_ABS, 判断dev->evbit中是否使能该type
spin_lock_irqsave(&dev->event_lock, flags); // 自旋锁 - 屏蔽多cpu抢占， irqsave - 屏蔽中断抢占
input_handle_event(dev, type, code, value);
spin_unlock_irqrestore(&dev->event_lock, flags);
}
}
EXPORT_SYMBOL(input_event);
/**
* input_inject_event() - send input event from input handler
* @handle: input handle to send event through
* @type: type of the event
* @code: event code
* @value: value of the event
*
* Similar to input_event() but will ignore event if device is
* "grabbed" and handle injecting event is not the one that owns
* the device.
*/
void input_inject_event(struct input_handle *handle,
unsigned int type, unsigned int code, int value)
{
struct input_dev *dev = handle->dev;
struct input_handle *grab;
unsigned long flags;
if (is_event_supported(type, dev->evbit, EV_MAX)) {
spin_lock_irqsave(&dev->event_lock, flags);
rcu_read_lock();
grab = rcu_dereference(dev->grab);
if (!grab || grab == handle)
input_handle_event(dev, type, code, value);
rcu_read_unlock();
spin_unlock_irqrestore(&dev->event_lock, flags);
}
}
EXPORT_SYMBOL(input_inject_event);
/**
* input_alloc_absinfo - allocates array of input_absinfo structs
* @dev: the input device emitting absolute events
*
* If the absinfo struct the caller asked for is already allocated, this
* functions will not do anything.
*/
void input_alloc_absinfo(struct input_dev *dev)
{
if (!dev->absinfo)
dev->absinfo = kcalloc(ABS_CNT, sizeof(struct input_absinfo),
GFP_KERNEL);
WARN(!dev->absinfo, "%s(): kcalloc() failed?\n", __func__);
}
EXPORT_SYMBOL(input_alloc_absinfo);
void input_set_abs_params(struct input_dev *dev, unsigned int axis,
int min, int max, int fuzz, int flat)
{
struct input_absinfo *absinfo;
input_alloc_absinfo(dev);
if (!dev->absinfo)
return;
absinfo = &dev->absinfo[axis];
absinfo->minimum = min;
absinfo->maximum = max;
absinfo->fuzz = fuzz;
absinfo->flat = flat;
__set_bit(EV_ABS, dev->evbit);
__set_bit(axis, dev->absbit);
}
EXPORT_SYMBOL(input_set_abs_params);
/**
* input_grab_device - grabs device for exclusive use
* @handle: input handle that wants to own the device
*
* When a device is grabbed by an input handle all events generated by
* the device are delivered only to this handle. Also events injected
* by other input handles are ignored while device is grabbed.
*/
int input_grab_device(struct input_handle *handle)
{
struct input_dev *dev = handle->dev;
int retval;
retval = mutex_lock_interruptible(&dev->mutex);
if (retval)
return retval;
if (dev->grab) {
retval = -EBUSY;
goto out;
}
rcu_assign_pointer(dev->grab, handle);
out:
mutex_unlock(&dev->mutex);
return retval;
}
EXPORT_SYMBOL(input_grab_device);
static void __input_release_device(struct input_handle *handle)
{
struct input_dev *dev = handle->dev;
struct input_handle *grabber;
grabber = rcu_dereference_protected(dev->grab,
lockdep_is_held(&dev->mutex));
if (grabber == handle) {
rcu_assign_pointer(dev->grab, NULL);
/* Make sure input_pass_event() notices that grab is gone */
synchronize_rcu();
list_for_each_entry(handle, &dev->h_list, d_node)
if (handle->open && handle->handler->start)
handle->handler->start(handle);
}
}
/**
* input_release_device - release previously grabbed device
* @handle: input handle that owns the device
*
* Releases previously grabbed device so that other input handles can
* start receiving input events. Upon release all handlers attached
* to the device have their start() method called so they have a change
* to synchronize device state with the rest of the system.
*/
void input_release_device(struct input_handle *handle)
{
struct input_dev *dev = handle->dev;
mutex_lock(&dev->mutex);
__input_release_device(handle);
mutex_unlock(&dev->mutex);
}
EXPORT_SYMBOL(input_release_device);
/**
* input_open_device - open input device
* @handle: handle through which device is being accessed
*
* This function should be called by input handlers when they
* want to start receive events from given input device.
*/
int input_open_device(struct input_handle *handle)
{
struct input_dev *dev = handle->dev;
int retval;
retval = mutex_lock_interruptible(&dev->mutex);
if (retval)
return retval;
if (dev->going_away) {
retval = -ENODEV;
goto out;
}
handle->open++;
if (!dev->users++ && dev->open)
retval = dev->open(dev);
if (retval) {
dev->users--;
if (!--handle->open) {
/*
* Make sure we are not delivering any more events
* through this handle
*/
synchronize_rcu();
}
}
out:
mutex_unlock(&dev->mutex);
return retval;
}
EXPORT_SYMBOL(input_open_device);
int input_flush_device(struct input_handle *handle, struct file *file)
{
struct input_dev *dev = handle->dev;
int retval;
retval = mutex_lock_interruptible(&dev->mutex);
if (retval)
return retval;
if (dev->flush)
retval = dev->flush(dev, file);
mutex_unlock(&dev->mutex);
return retval;
}
EXPORT_SYMBOL(input_flush_device);
/**
* input_close_device - close input device
* @handle: handle through which device is being accessed
*
* This function should be called by input handlers when they
* want to stop receive events from given input device.
*/
void input_close_device(struct input_handle *handle)
{
struct input_dev *dev = handle->dev;
mutex_lock(&dev->mutex);
__input_release_device(handle);
if (!--dev->users && dev->close)
dev->close(dev);
if (!--handle->open) {
/*
* synchronize_rcu() makes sure that input_pass_event()
* completed and that no more input events are delivered
* through this handle
*/
synchronize_rcu();
}
mutex_unlock(&dev->mutex);
}
EXPORT_SYMBOL(input_close_device);
/*
* Simulate keyup events for all keys that are marked as pressed.
* The function must be called with dev->event_lock held.
*/
static void input_dev_release_keys(struct input_dev *dev)
{
int code;
bool need_sync = false;
if (is_event_supported(EV_KEY, dev->evbit, EV_MAX)) {
for (code = 0; code <= KEY_MAX; code++) {
if (is_event_supported(code, dev->keybit, KEY_MAX) &&
__test_and_clear_bit(code, dev->key)) {
input_pass_event(dev, EV_KEY, code, 0);
need_sync = true;
}
}
if (need_sync)
input_pass_event(dev, EV_SYN, SYN_REPORT, 1);
}
}
/*
* Prepare device for unregistering
*/
static void input_disconnect_device(struct input_dev *dev)
{
struct input_handle *handle;
/*
* Mark device as going away. Note that we take dev->mutex here
* not to protect access to dev->going_away but rather to ensure
* that there are no threads in the middle of input_open_device()
*/
mutex_lock(&dev->mutex);
dev->going_away = true;
mutex_unlock(&dev->mutex);
spin_lock_irq(&dev->event_lock);
/*
* Simulate keyup events for all pressed keys so that handlers
* are not left with "stuck" keys. The driver may continue
* generate events even after we done here but they will not
* reach any handlers.
*/
input_dev_release_keys(dev);
list_for_each_entry(handle, &dev->h_list, d_node)
handle->open = 0;
spin_unlock_irq(&dev->event_lock);
}
/**
* input_scancode_to_scalar() - converts scancode in &struct input_keymap_entry
* @ke: keymap entry containing scancode to be converted.
* @scancode: pointer to the location where converted scancode should
* be stored.
*
* This function is used to convert scancode stored in &struct keymap_entry
* into scalar form understood by legacy keymap handling methods. These
* methods expect scancodes to be represented as 'unsigned int'.
*/
int input_scancode_to_scalar(const struct input_keymap_entry *ke,
unsigned int *scancode)
{
switch (ke->len) {
case 1:
*scancode = *((u8 *)ke->scancode);
break;
case 2:
*scancode = *((u16 *)ke->scancode);
break;
case 4:
*scancode = *((u32 *)ke->scancode);
break;
default:
return -EINVAL;
}
return 0;
}
EXPORT_SYMBOL(input_scancode_to_scalar);
/*
* Those routines handle the default case where no [gs]etkeycode() is
* defined. In this case, an array indexed by the scancode is used.
*/
static unsigned int input_fetch_keycode(struct input_dev *dev,
unsigned int index)
{
switch (dev->keycodesize) {
case 1:
return ((u8 *)dev->keycode)[index];
case 2:
return ((u16 *)dev->keycode)[index];
default:
return ((u32 *)dev->keycode)[index];
}
}
static int input_default_getkeycode(struct input_dev *dev,
struct input_keymap_entry *ke)
{
unsigned int index;
int error;
if (!dev->keycodesize)
return -EINVAL;
if (ke->flags & INPUT_KEYMAP_BY_INDEX)
index = ke->index;
else {
error = input_scancode_to_scalar(ke, &index);
if (error)
return error;
}
if (index >= dev->keycodemax)
return -EINVAL;
ke->keycode = input_fetch_keycode(dev, index);
ke->index = index;
ke->len = sizeof(index);
memcpy(ke->scancode, &index, sizeof(index));
return 0;
}
static int input_default_setkeycode(struct input_dev *dev,
const struct input_keymap_entry *ke,
unsigned int *old_keycode)
{
unsigned int index;
int error;
int i;
if (!dev->keycodesize)
return -EINVAL;
if (ke->flags & INPUT_KEYMAP_BY_INDEX) {
index = ke->index;
} else {
error = input_scancode_to_scalar(ke, &index);
if (error)
return error;
}
if (index >= dev->keycodemax)
return -EINVAL;
if (dev->keycodesize < sizeof(ke->keycode) &&
(ke->keycode >> (dev->keycodesize * 8)))
return -EINVAL;
switch (dev->keycodesize) {
case 1: {
u8 *k = (u8 *)dev->keycode;
*old_keycode = k[index];
k[index] = ke->keycode;
break;
}
case 2: {
u16 *k = (u16 *)dev->keycode;
*old_keycode = k[index];
k[index] = ke->keycode;
break;
}
default: {
u32 *k = (u32 *)dev->keycode;
*old_keycode = k[index];
k[index] = ke->keycode;
break;
}
}
__clear_bit(*old_keycode, dev->keybit);
__set_bit(ke->keycode, dev->keybit);
for (i = 0; i < dev->keycodemax; i++) {
if (input_fetch_keycode(dev, i) == *old_keycode) {
__set_bit(*old_keycode, dev->keybit);
break; /* Setting the bit twice is useless, so break */
}
}
return 0;
}
/**
* input_get_keycode - retrieve keycode currently mapped to a given scancode
* @dev: input device which keymap is being queried
* @ke: keymap entry
*
* This function should be called by anyone interested in retrieving current
* keymap. Presently evdev handlers use it.
*/
int input_get_keycode(struct input_dev *dev, struct input_keymap_entry *ke)
{
unsigned long flags;
int retval;
spin_lock_irqsave(&dev->event_lock, flags);
retval = dev->getkeycode(dev, ke);
spin_unlock_irqrestore(&dev->event_lock, flags);
return retval;
}
EXPORT_SYMBOL(input_get_keycode);
/**
* input_set_keycode - attribute a keycode to a given scancode
* @dev: input device which keymap is being updated
* @ke: new keymap entry
*
* This function should be called by anyone needing to update current
* keymap. Presently keyboard and evdev handlers use it.
*/
int input_set_keycode(struct input_dev *dev,
const struct input_keymap_entry *ke)
{
unsigned long flags;
unsigned int old_keycode;
int retval;
if (ke->keycode > KEY_MAX)
return -EINVAL;
spin_lock_irqsave(&dev->event_lock, flags);
retval = dev->setkeycode(dev, ke, &old_keycode);
if (retval)
goto out;
/* Make sure KEY_RESERVED did not get enabled. */
__clear_bit(KEY_RESERVED, dev->keybit);
/*
* Simulate keyup event if keycode is not present
* in the keymap anymore
*/
if (test_bit(EV_KEY, dev->evbit) &&
!is_event_supported(old_keycode, dev->keybit, KEY_MAX) &&
__test_and_clear_bit(old_keycode, dev->key)) {
struct input_value vals[] = {
{ EV_KEY, old_keycode, 0 },
input_value_sync
};
input_pass_values(dev, vals, ARRAY_SIZE(vals));
}
out:
spin_unlock_irqrestore(&dev->event_lock, flags);
return retval;
}
EXPORT_SYMBOL(input_set_keycode);
static const struct input_device_id *input_match_device(struct input_handler *handler,
struct input_dev *dev)
{
const struct input_device_id *id;
for (id = handler->id_table; id->flags || id->driver_info; id++) {
if (id->flags & INPUT_DEVICE_ID_MATCH_BUS)
if (id->bustype != dev->id.bustype)
continue;
if (id->flags & INPUT_DEVICE_ID_MATCH_VENDOR)
if (id->vendor != dev->id.vendor)
continue;
if (id->flags & INPUT_DEVICE_ID_MATCH_PRODUCT)
if (id->product != dev->id.product)
continue;
if (id->flags & INPUT_DEVICE_ID_MATCH_VERSION)
if (id->version != dev->id.version)
continue;
if (!bitmap_subset(id->evbit, dev->evbit, EV_MAX))
continue;
if (!bitmap_subset(id->keybit, dev->keybit, KEY_MAX))
continue;
if (!bitmap_subset(id->relbit, dev->relbit, REL_MAX))
continue;
if (!bitmap_subset(id->absbit, dev->absbit, ABS_MAX))
continue;
if (!bitmap_subset(id->mscbit, dev->mscbit, MSC_MAX))
continue;
if (!bitmap_subset(id->ledbit, dev->ledbit, LED_MAX))
continue;
if (!bitmap_subset(id->sndbit, dev->sndbit, SND_MAX))
continue;
if (!bitmap_subset(id->ffbit, dev->ffbit, FF_MAX))
continue;
if (!bitmap_subset(id->swbit, dev->swbit, SW_MAX))
continue;
if (!handler->match || handler->match(handler, dev))
return id;
}
return NULL;
}
static int input_attach_handler(struct input_dev *dev, struct input_handler *handler)
{
const struct input_device_id *id;
int error;
id = input_match_device(handler, dev);
if (!id)
return -ENODEV;
error = handler->connect(handler, dev, id);
if (error && error != -ENODEV)
pr_err("failed to attach handler %s to device %s, error: %d\n",
handler->name, kobject_name(&dev->dev.kobj), error);
return error;
}
#ifdef CONFIG_COMPAT
static int input_bits_to_string(char *buf, int buf_size,
unsigned long bits, bool skip_empty)
{
int len = 0;
if (INPUT_COMPAT_TEST) {
u32 dword = bits >> 32;
if (dword || !skip_empty)
len += snprintf(buf, buf_size, "%x ", dword);
dword = bits & 0xffffffffUL;
if (dword || !skip_empty || len)
len += snprintf(buf + len, max(buf_size - len, 0),
"%x", dword);
} else {
if (bits || !skip_empty)
len += snprintf(buf, buf_size, "%lx", bits);
}
return len;
}
#else /* !CONFIG_COMPAT */
static int input_bits_to_string(char *buf, int buf_size,
unsigned long bits, bool skip_empty)
{
return bits || !skip_empty ?
snprintf(buf, buf_size, "%lx", bits) : 0;
}
#endif
#ifdef CONFIG_PROC_FS
static struct proc_dir_entry *proc_bus_input_dir;
static DECLARE_WAIT_QUEUE_HEAD(input_devices_poll_wait);
static int input_devices_state;
static inline void input_wakeup_procfs_readers(void)
{
input_devices_state++;
wake_up(&input_devices_poll_wait);
}
static unsigned int input_proc_devices_poll(struct file *file, poll_table *wait)
{
poll_wait(file, &input_devices_poll_wait, wait);
if (file->f_version != input_devices_state) {
file->f_version = input_devices_state;
return POLLIN | POLLRDNORM;
}
return 0;
}
union input_seq_state {
struct {
unsigned short pos;
bool mutex_acquired;
};
void *p;
};
static void *input_devices_seq_start(struct seq_file *seq, loff_t *pos)
{
union input_seq_state *state = (union input_seq_state *)&seq->private;
int error;
/* We need to fit into seq->private pointer */
BUILD_BUG_ON(sizeof(union input_seq_state) != sizeof(seq->private));
error = mutex_lock_interruptible(&input_mutex);
if (error) {
state->mutex_acquired = false;
return ERR_PTR(error);
}
state->mutex_acquired = true;
return seq_list_start(&input_dev_list, *pos);
}
static void *input_devices_seq_next(struct seq_file *seq, void *v, loff_t *pos)
{
return seq_list_next(v, &input_dev_list, pos);
}
static void input_seq_stop(struct seq_file *seq, void *v)
{
union input_seq_state *state = (union input_seq_state *)&seq->private;
if (state->mutex_acquired)
mutex_unlock(&input_mutex);
}
static void input_seq_print_bitmap(struct seq_file *seq, const char *name,
unsigned long *bitmap, int max)
{
int i;
bool skip_empty = true;
char buf[18];
seq_printf(seq, "B: %s=", name);
for (i = BITS_TO_LONGS(max) - 1; i >= 0; i--) {
if (input_bits_to_string(buf, sizeof(buf),
bitmap[i], skip_empty)) {
skip_empty = false;
seq_printf(seq, "%s%s", buf, i > 0 ? " " : "");
}
}
/*
* If no output was produced print a single 0.
*/
if (skip_empty)
seq_puts(seq, "0");
seq_putc(seq, '\n');
}
static int input_devices_seq_show(struct seq_file *seq, void *v)
{
struct input_dev *dev = container_of(v, struct input_dev, node);
const char *path = kobject_get_path(&dev->dev.kobj, GFP_KERNEL);
struct input_handle *handle;
seq_printf(seq, "I: Bus=%04x Vendor=%04x Product=%04x Version=%04x\n",
dev->id.bustype, dev->id.vendor, dev->id.product, dev->id.version);
seq_printf(seq, "N: Name=\"%s\"\n", dev->name ? dev->name : "");
seq_printf(seq, "P: Phys=%s\n", dev->phys ? dev->phys : "");
seq_printf(seq, "S: Sysfs=%s\n", path ? path : "");
seq_printf(seq, "U: Uniq=%s\n", dev->uniq ? dev->uniq : "");
seq_printf(seq, "H: Handlers=");
list_for_each_entry(handle, &dev->h_list, d_node)
seq_printf(seq, "%s ", handle->name);
seq_putc(seq, '\n');
input_seq_print_bitmap(seq, "PROP", dev->propbit, INPUT_PROP_MAX);
input_seq_print_bitmap(seq, "EV", dev->evbit, EV_MAX);
if (test_bit(EV_KEY, dev->evbit))
input_seq_print_bitmap(seq, "KEY", dev->keybit, KEY_MAX);
if (test_bit(EV_REL, dev->evbit))
input_seq_print_bitmap(seq, "REL", dev->relbit, REL_MAX);
if (test_bit(EV_ABS, dev->evbit))
input_seq_print_bitmap(seq, "ABS", dev->absbit, ABS_MAX);
if (test_bit(EV_MSC, dev->evbit))
input_seq_print_bitmap(seq, "MSC", dev->mscbit, MSC_MAX);
if (test_bit(EV_LED, dev->evbit))
input_seq_print_bitmap(seq, "LED", dev->ledbit, LED_MAX);
if (test_bit(EV_SND, dev->evbit))
input_seq_print_bitmap(seq, "SND", dev->sndbit, SND_MAX);
if (test_bit(EV_FF, dev->evbit))
input_seq_print_bitmap(seq, "FF", dev->ffbit, FF_MAX);
if (test_bit(EV_SW, dev->evbit))
input_seq_print_bitmap(seq, "SW", dev->swbit, SW_MAX);
seq_putc(seq, '\n');
kfree(path);
return 0;
}
static const struct seq_operations input_devices_seq_ops = {
.start = input_devices_seq_start,
.next = input_devices_seq_next,
.stop = input_seq_stop,
.show = input_devices_seq_show,
};
static int input_proc_devices_open(struct inode *inode, struct file *file)
{
return seq_open(file, &input_devices_seq_ops);
}
static const struct file_operations input_devices_fileops = {
.owner = THIS_MODULE,
.open = input_proc_devices_open,
.poll = input_proc_devices_poll,
.read = seq_read,
.llseek = seq_lseek,
.release = seq_release,
};
static void *input_handlers_seq_start(struct seq_file *seq, loff_t *pos)
{
union input_seq_state *state = (union input_seq_state *)&seq->private;
int error;
/* We need to fit into seq->private pointer */
BUILD_BUG_ON(sizeof(union input_seq_state) != sizeof(seq->private));
error = mutex_lock_interruptible(&input_mutex);
if (error) {
state->mutex_acquired = false;
return ERR_PTR(error);
}
state->mutex_acquired = true;
state->pos = *pos;
return seq_list_start(&input_handler_list, *pos);
}
static void *input_handlers_seq_next(struct seq_file *seq, void *v, loff_t *pos)
{
union input_seq_state *state = (union input_seq_state *)&seq->private;
state->pos = *pos + 1;
return seq_list_next(v, &input_handler_list, pos);
}
static int input_handlers_seq_show(struct seq_file *seq, void *v)
{
struct input_handler *handler = container_of(v, struct input_handler, node);
union input_seq_state *state = (union input_seq_state *)&seq->private;
seq_printf(seq, "N: Number=%u Name=%s", state->pos, handler->name);
if (handler->filter)
seq_puts(seq, " (filter)");
if (handler->legacy_minors)
seq_printf(seq, " Minor=%d", handler->minor);
seq_putc(seq, '\n');
return 0;
}
static const struct seq_operations input_handlers_seq_ops = {
.start = input_handlers_seq_start,
.next = input_handlers_seq_next,
.stop = input_seq_stop,
.show = input_handlers_seq_show,
};
static int input_proc_handlers_open(struct inode *inode, struct file *file)
{
return seq_open(file, &input_handlers_seq_ops);
}
static const struct file_operations input_handlers_fileops = {
.owner = THIS_MODULE,
.open = input_proc_handlers_open,
.read = seq_read,
.llseek = seq_lseek,
.release = seq_release,
};
static int __init input_proc_init(void)
{
struct proc_dir_entry *entry;
proc_bus_input_dir = proc_mkdir("bus/input", NULL); // 创建文件夹"/proc/bus/input"
if (!proc_bus_input_dir)
return -ENOMEM;
entry = proc_create("devices", 0, proc_bus_input_dir,// 创建节点"/proc/bus/input/devices"
&input_devices_fileops);
if (!entry)
goto fail1;
entry = proc_create("handlers", 0, proc_bus_input_dir,// 创建节点"/proc/bus/input/handlers"
&input_handlers_fileops);
if (!entry)
goto fail2;
return 0;
fail2: remove_proc_entry("devices", proc_bus_input_dir);
fail1: remove_proc_entry("bus/input", NULL);
return -ENOMEM;
}
static void input_proc_exit(void)
{
remove_proc_entry("devices", proc_bus_input_dir);
remove_proc_entry("handlers", proc_bus_input_dir);
remove_proc_entry("bus/input", NULL);
}
#else /* !CONFIG_PROC_FS */
static inline void input_wakeup_procfs_readers(void) { }
static inline int input_proc_init(void) { return 0; }
static inline void input_proc_exit(void) { }
#endif
#define INPUT_DEV_STRING_ATTR_SHOW(name) \
static ssize_t input_dev_show_##name(struct device *dev, \
struct device_attribute *attr, \
char *buf) \
{ \
struct input_dev *input_dev = to_input_dev(dev); \
\
return scnprintf(buf, PAGE_SIZE, "%s\n", \
input_dev->name ? input_dev->name : ""); \
} \
static DEVICE_ATTR(name, S_IRUGO, input_dev_show_##name, NULL)
INPUT_DEV_STRING_ATTR_SHOW(name);
INPUT_DEV_STRING_ATTR_SHOW(phys);
INPUT_DEV_STRING_ATTR_SHOW(uniq);
static int input_print_modalias_bits(char *buf, int size,
char name, unsigned long *bm,
unsigned int min_bit, unsigned int max_bit)
{
int len = 0, i;
len += snprintf(buf, max(size, 0), "%c", name);
for (i = min_bit; i < max_bit; i++)
if (bm[BIT_WORD(i)] & BIT_MASK(i))
len += snprintf(buf + len, max(size - len, 0), "%X,", i);
return len;
}
static int input_print_modalias(char *buf, int size, struct input_dev *id,
int add_cr)
{
int len;
len = snprintf(buf, max(size, 0),
"input:b%04Xv%04Xp%04Xe%04X-",
id->id.bustype, id->id.vendor,
id->id.product, id->id.version);
len += input_print_modalias_bits(buf + len, size - len,
'e', id->evbit, 0, EV_MAX);
len += input_print_modalias_bits(buf + len, size - len,
'k', id->keybit, KEY_MIN_INTERESTING, KEY_MAX);
len += input_print_modalias_bits(buf + len, size - len,
'r', id->relbit, 0, REL_MAX);
len += input_print_modalias_bits(buf + len, size - len,
'a', id->absbit, 0, ABS_MAX);
len += input_print_modalias_bits(buf + len, size - len,
'm', id->mscbit, 0, MSC_MAX);
len += input_print_modalias_bits(buf + len, size - len,
'l', id->ledbit, 0, LED_MAX);
len += input_print_modalias_bits(buf + len, size - len,
's', id->sndbit, 0, SND_MAX);
len += input_print_modalias_bits(buf + len, size - len,
'f', id->ffbit, 0, FF_MAX);
len += input_print_modalias_bits(buf + len, size - len,
'w', id->swbit, 0, SW_MAX);
if (add_cr)
len += snprintf(buf + len, max(size - len, 0), "\n");
return len;
}
static ssize_t input_dev_show_modalias(struct device *dev,
struct device_attribute *attr,
char *buf)
{
struct input_dev *id = to_input_dev(dev);
ssize_t len;
len = input_print_modalias(buf, PAGE_SIZE, id, 1);
return min_t(int, len, PAGE_SIZE);
}
static DEVICE_ATTR(modalias, S_IRUGO, input_dev_show_modalias, NULL);
static int input_print_bitmap(char *buf, int buf_size, unsigned long *bitmap,
int max, int add_cr);
static ssize_t input_dev_show_properties(struct device *dev,
struct device_attribute *attr,
char *buf)
{
struct input_dev *input_dev = to_input_dev(dev);
int len = input_print_bitmap(buf, PAGE_SIZE, input_dev->propbit,
INPUT_PROP_MAX, true);
return min_t(int, len, PAGE_SIZE);
}
static DEVICE_ATTR(properties, S_IRUGO, input_dev_show_properties, NULL);
static struct attribute *input_dev_attrs[] = {
&dev_attr_name.attr,
&dev_attr_phys.attr,
&dev_attr_uniq.attr,
&dev_attr_modalias.attr,
&dev_attr_properties.attr,
NULL
};
static struct attribute_group input_dev_attr_group = {
.attrs = input_dev_attrs,
};
#define INPUT_DEV_ID_ATTR(name) \
static ssize_t input_dev_show_id_##name(struct device *dev, \
struct device_attribute *attr, \
char *buf) \
{ \
struct input_dev *input_dev = to_input_dev(dev); \
return scnprintf(buf, PAGE_SIZE, "%04x\n", input_dev->id.name); \
} \
static DEVICE_ATTR(name, S_IRUGO, input_dev_show_id_##name, NULL)
INPUT_DEV_ID_ATTR(bustype);
INPUT_DEV_ID_ATTR(vendor);
INPUT_DEV_ID_ATTR(product);
INPUT_DEV_ID_ATTR(version);
static struct attribute *input_dev_id_attrs[] = {
&dev_attr_bustype.attr,
&dev_attr_vendor.attr,
&dev_attr_product.attr,
&dev_attr_version.attr,
NULL
};
static struct attribute_group input_dev_id_attr_group = {
.name = "id",
.attrs = input_dev_id_attrs,
};
static int input_print_bitmap(char *buf, int buf_size, unsigned long *bitmap,
int max, int add_cr)
{
int i;
int len = 0;
bool skip_empty = true;
for (i = BITS_TO_LONGS(max) - 1; i >= 0; i--) {
len += input_bits_to_string(buf + len, max(buf_size - len, 0),
bitmap[i], skip_empty);
if (len) {
skip_empty = false;
if (i > 0)
len += snprintf(buf + len, max(buf_size - len, 0), " ");
}
}
/*
* If no output was produced print a single 0.
*/
if (len == 0)
len = snprintf(buf, buf_size, "%d", 0);
if (add_cr)
len += snprintf(buf + len, max(buf_size - len, 0), "\n");
return len;
}
#define INPUT_DEV_CAP_ATTR(ev, bm) \
static ssize_t input_dev_show_cap_##bm(struct device *dev, \
struct device_attribute *attr, \
char *buf) \
{ \
struct input_dev *input_dev = to_input_dev(dev); \
int len = input_print_bitmap(buf, PAGE_SIZE, \
input_dev->bm##bit, ev##_MAX, \
true); \
return min_t(int, len, PAGE_SIZE); \
} \
static DEVICE_ATTR(bm, S_IRUGO, input_dev_show_cap_##bm, NULL)
INPUT_DEV_CAP_ATTR(EV, ev);
INPUT_DEV_CAP_ATTR(KEY, key);
INPUT_DEV_CAP_ATTR(REL, rel);
INPUT_DEV_CAP_ATTR(ABS, abs);
INPUT_DEV_CAP_ATTR(MSC, msc);
INPUT_DEV_CAP_ATTR(LED, led);
INPUT_DEV_CAP_ATTR(SND, snd);
INPUT_DEV_CAP_ATTR(FF, ff);
INPUT_DEV_CAP_ATTR(SW, sw);
static struct attribute *input_dev_caps_attrs[] = {
&dev_attr_ev.attr,
&dev_attr_key.attr,
&dev_attr_rel.attr,
&dev_attr_abs.attr,
&dev_attr_msc.attr,
&dev_attr_led.attr,
&dev_attr_snd.attr,
&dev_attr_ff.attr,
&dev_attr_sw.attr,
NULL
};
static struct attribute_group input_dev_caps_attr_group = {
.name = "capabilities",
.attrs = input_dev_caps_attrs,
};
static const struct attribute_group *input_dev_attr_groups[] = {
&input_dev_attr_group,
&input_dev_id_attr_group,
&input_dev_caps_attr_group,
NULL
};
static void input_dev_release(struct device *device)
{
struct input_dev *dev = to_input_dev(device);
input_ff_destroy(dev);
input_mt_destroy_slots(dev);
kfree(dev->absinfo);
kfree(dev->vals);
kfree(dev);
module_put(THIS_MODULE);
}
/*
* Input uevent interface - loading event handlers based on
* device bitfields.
*/
static int input_add_uevent_bm_var(struct kobj_uevent_env *env,
const char *name, unsigned long *bitmap, int max)
{
int len;
if (add_uevent_var(env, "%s", name))
return -ENOMEM;
len = input_print_bitmap(&env->buf[env->buflen - 1],
sizeof(env->buf) - env->buflen,
bitmap, max, false);
if (len >= (sizeof(env->buf) - env->buflen))
return -ENOMEM;
env->buflen += len;
return 0;
}
static int input_add_uevent_modalias_var(struct kobj_uevent_env *env,
struct input_dev *dev)
{
int len;
if (add_uevent_var(env, "MODALIAS="))
return -ENOMEM;
len = input_print_modalias(&env->buf[env->buflen - 1],
sizeof(env->buf) - env->buflen,
dev, 0);
if (len >= (sizeof(env->buf) - env->buflen))
return -ENOMEM;
env->buflen += len;
return 0;
}
#define INPUT_ADD_HOTPLUG_VAR(fmt, val...) \
do { \
int err = add_uevent_var(env, fmt, val); \
if (err) \
return err; \
} while (0)
#define INPUT_ADD_HOTPLUG_BM_VAR(name, bm, max) \
do { \
int err = input_add_uevent_bm_var(env, name, bm, max); \
if (err) \
return err; \
} while (0)
#define INPUT_ADD_HOTPLUG_MODALIAS_VAR(dev) \
do { \
int err = input_add_uevent_modalias_var(env, dev); \
if (err) \
return err; \
} while (0)
static int input_dev_uevent(struct device *device, struct kobj_uevent_env *env)
{
struct input_dev *dev = to_input_dev(device);
INPUT_ADD_HOTPLUG_VAR("PRODUCT=%x/%x/%x/%x",
dev->id.bustype, dev->id.vendor,
dev->id.product, dev->id.version);
if (dev->name)
INPUT_ADD_HOTPLUG_VAR("NAME=\"%s\"", dev->name);
if (dev->phys)
INPUT_ADD_HOTPLUG_VAR("PHYS=\"%s\"", dev->phys);
if (dev->uniq)
INPUT_ADD_HOTPLUG_VAR("UNIQ=\"%s\"", dev->uniq);
INPUT_ADD_HOTPLUG_BM_VAR("PROP=", dev->propbit, INPUT_PROP_MAX);
INPUT_ADD_HOTPLUG_BM_VAR("EV=", dev->evbit, EV_MAX);
if (test_bit(EV_KEY, dev->evbit))
INPUT_ADD_HOTPLUG_BM_VAR("KEY=", dev->keybit, KEY_MAX);
if (test_bit(EV_REL, dev->evbit))
INPUT_ADD_HOTPLUG_BM_VAR("REL=", dev->relbit, REL_MAX);
if (test_bit(EV_ABS, dev->evbit))
INPUT_ADD_HOTPLUG_BM_VAR("ABS=", dev->absbit, ABS_MAX);
if (test_bit(EV_MSC, dev->evbit))
INPUT_ADD_HOTPLUG_BM_VAR("MSC=", dev->mscbit, MSC_MAX);
if (test_bit(EV_LED, dev->evbit))
INPUT_ADD_HOTPLUG_BM_VAR("LED=", dev->ledbit, LED_MAX);
if (test_bit(EV_SND, dev->evbit))
INPUT_ADD_HOTPLUG_BM_VAR("SND=", dev->sndbit, SND_MAX);
if (test_bit(EV_FF, dev->evbit))
INPUT_ADD_HOTPLUG_BM_VAR("FF=", dev->ffbit, FF_MAX);
if (test_bit(EV_SW, dev->evbit))
INPUT_ADD_HOTPLUG_BM_VAR("SW=", dev->swbit, SW_MAX);
INPUT_ADD_HOTPLUG_MODALIAS_VAR(dev);
return 0;
}
#define INPUT_DO_TOGGLE(dev, type, bits, on) \
do { \
int i; \
bool active; \
\
if (!test_bit(EV_##type, dev->evbit)) \
break; \
\
for (i = 0; i < type##_MAX; i++) { \
if (!test_bit(i, dev->bits##bit)) \
continue; \
\
active = test_bit(i, dev->bits); \
if (!active && !on) \
continue; \
\
dev->event(dev, EV_##type, i, on ? active : 0); \
} \
} while (0)
static void input_dev_toggle(struct input_dev *dev, bool activate)
{
if (!dev->event)
return;
INPUT_DO_TOGGLE(dev, LED, led, activate);
INPUT_DO_TOGGLE(dev, SND, snd, activate);
if (activate && test_bit(EV_REP, dev->evbit)) {
dev->event(dev, EV_REP, REP_PERIOD, dev->rep[REP_PERIOD]);
dev->event(dev, EV_REP, REP_DELAY, dev->rep[REP_DELAY]);
}
}
/**
* input_reset_device() - reset/restore the state of input device
* @dev: input device whose state needs to be reset
*
* This function tries to reset the state of an opened input device and
* bring internal state and state if the hardware in sync with each other.
* We mark all keys as released, restore LED state, repeat rate, etc.
*/
void input_reset_device(struct input_dev *dev)
{
unsigned long flags;
mutex_lock(&dev->mutex);
spin_lock_irqsave(&dev->event_lock, flags);
input_dev_toggle(dev, true);
input_dev_release_keys(dev);
spin_unlock_irqrestore(&dev->event_lock, flags);
mutex_unlock(&dev->mutex);
}
EXPORT_SYMBOL(input_reset_device);
#ifdef CONFIG_PM_SLEEP
static int input_dev_suspend(struct device *dev)
{
struct input_dev *input_dev = to_input_dev(dev);
spin_lock_irq(&input_dev->event_lock);
/*
* Keys that are pressed now are unlikely to be
* still pressed when we resume.
*/
input_dev_release_keys(input_dev);
/* Turn off LEDs and sounds, if any are active. */
input_dev_toggle(input_dev, false);
spin_unlock_irq(&input_dev->event_lock);
return 0;
}
static int input_dev_resume(struct device *dev)
{
struct input_dev *input_dev = to_input_dev(dev);
spin_lock_irq(&input_dev->event_lock);
/* Restore state of LEDs and sounds, if any were active. */
input_dev_toggle(input_dev, true);
spin_unlock_irq(&input_dev->event_lock);
return 0;
}
static int input_dev_freeze(struct device *dev)
{
struct input_dev *input_dev = to_input_dev(dev);
spin_lock_irq(&input_dev->event_lock);
/*
* Keys that are pressed now are unlikely to be
* still pressed when we resume.
*/
input_dev_release_keys(input_dev);
spin_unlock_irq(&input_dev->event_lock);
return 0;
}
static int input_dev_poweroff(struct device *dev)
{
struct input_dev *input_dev = to_input_dev(dev);
spin_lock_irq(&input_dev->event_lock);
/* Turn off LEDs and sounds, if any are active. */
input_dev_toggle(input_dev, false);
spin_unlock_irq(&input_dev->event_lock);
return 0;
}
static const struct dev_pm_ops input_dev_pm_ops = {
.suspend = input_dev_suspend,
.resume = input_dev_resume,
.freeze = input_dev_freeze,
.poweroff = input_dev_poweroff,
.restore = input_dev_resume,
};
#endif /* CONFIG_PM */
static struct device_type input_dev_type = {
.groups = input_dev_attr_groups,
.release = input_dev_release,
.uevent = input_dev_uevent,
#ifdef CONFIG_PM_SLEEP
.pm = &input_dev_pm_ops,
#endif
};
static char *input_devnode(struct device *dev, umode_t *mode)
{
return kasprintf(GFP_KERNEL, "input/%s", dev_name(dev));
}
struct class input_class = {
.name = "input",
.devnode = input_devnode,
};
EXPORT_SYMBOL_GPL(input_class);
struct input_devres {
struct input_dev *input;
};
static int devm_input_device_match(struct device *dev, void *res, void *data)
{
struct input_devres *devres = res;
return devres->input == data;
}
static void devm_input_device_release(struct device *dev, void *res)
{
struct input_devres *devres = res;
struct input_dev *input = devres->input;
dev_dbg(dev, "%s: dropping reference to %s\n",
__func__, dev_name(&input->dev));
input_put_device(input);
}
/**
* devm_input_allocate_device - allocate managed input device
* @dev: device owning the input device being created
*
* Returns prepared struct input_dev or %NULL.
*
* Managed input devices do not need to be explicitly unregistered or
* freed as it will be done automatically when owner device unbinds from
* its driver (or binding fails). Once managed input device is allocated,
* it is ready to be set up and registered in the same fashion as regular
* input device. There are no special devm_input_device_[un]register()
* variants, regular ones work with both managed and unmanaged devices,
* should you need them. In most cases however, managed input device need
* not be explicitly unregistered or freed.
*
* NOTE: the owner device is set up as parent of input device and users
* should not override it.
*/
struct input_dev *devm_input_allocate_device(struct device *dev)
{
struct input_dev *input;
struct input_devres *devres;
devres = devres_alloc(devm_input_device_release,
sizeof(struct input_devres), GFP_KERNEL);
if (!devres)
return NULL;
input = input_allocate_device();
if (!input) {
devres_free(devres);
return NULL;
}
input->dev.parent = dev;
input->devres_managed = true;
devres->input = input;
devres_add(dev, devres);
return input;
}
EXPORT_SYMBOL(devm_input_allocate_device);
/**
* input_free_device - free memory occupied by input_dev structure
* @dev: input device to free
*
* This function should only be used if input_register_device()
* was not called yet or if it failed. Once device was registered
* use input_unregister_device() and memory will be freed once last
* reference to the device is dropped.
*
* Device should be allocated by input_allocate_device().
*
* NOTE: If there are references to the input device then memory
* will not be freed until last reference is dropped.
*/
void input_free_device(struct input_dev *dev)
{
if (dev) {
if (dev->devres_managed)
WARN_ON(devres_destroy(dev->dev.parent,
devm_input_device_release,
devm_input_device_match,
dev));
input_put_device(dev);
}
}
EXPORT_SYMBOL(input_free_device);
/**
* input_set_capability - mark device as capable of a certain event
* @dev: device that is capable of emitting or accepting event
* @type: type of the event (EV_KEY, EV_REL, etc...)
* @code: event code
*
* In addition to setting up corresponding bit in appropriate capability
* bitmap the function also adjusts dev->evbit.
*/
void input_set_capability(struct input_dev *dev, unsigned int type, unsigned int code)
{
switch (type) {
case EV_KEY:
__set_bit(code, dev->keybit);
break;
case EV_REL:
__set_bit(code, dev->relbit);
break;
case EV_ABS:
input_alloc_absinfo(dev);
if (!dev->absinfo)
return;
__set_bit(code, dev->absbit);
break;
case EV_MSC:
__set_bit(code, dev->mscbit);
break;
case EV_SW:
__set_bit(code, dev->swbit);
break;
case EV_LED:
__set_bit(code, dev->ledbit);
break;
case EV_SND:
__set_bit(code, dev->sndbit);
break;
case EV_FF:
__set_bit(code, dev->ffbit);
break;
case EV_PWR:
/* do nothing */
break;
default:
pr_err("input_set_capability: unknown type %u (code %u)\n",
type, code);
dump_stack();
return;
}
__set_bit(type, dev->evbit);
}
EXPORT_SYMBOL(input_set_capability);
static unsigned int input_estimate_events_per_packet(struct input_dev *dev)
{
int mt_slots;
int i;
unsigned int events;
if (dev->mt) {
mt_slots = dev->mt->num_slots;
} else if (test_bit(ABS_MT_TRACKING_ID, dev->absbit)) {
mt_slots = dev->absinfo[ABS_MT_TRACKING_ID].maximum -
dev->absinfo[ABS_MT_TRACKING_ID].minimum + 1,
mt_slots = clamp(mt_slots, 2, 32);
} else if (test_bit(ABS_MT_POSITION_X, dev->absbit)) {
mt_slots = 2;
} else {
mt_slots = 0;
}
events = mt_slots + 1; /* count SYN_MT_REPORT and SYN_REPORT */
for (i = 0; i < ABS_CNT; i++) {
if (test_bit(i, dev->absbit)) {
if (input_is_mt_axis(i))
events += mt_slots;
else
events++;
}
}
for (i = 0; i < REL_CNT; i++)
if (test_bit(i, dev->relbit))
events++;
/* Make room for KEY and MSC events */
events += 7;
return events;
}
#define INPUT_CLEANSE_BITMASK(dev, type, bits) \
do { \
if (!test_bit(EV_##type, dev->evbit)) \
memset(dev->bits##bit, 0, \
sizeof(dev->bits##bit)); \
} while (0)
static void input_cleanse_bitmasks(struct input_dev *dev)
{
INPUT_CLEANSE_BITMASK(dev, KEY, key);
INPUT_CLEANSE_BITMASK(dev, REL, rel);
INPUT_CLEANSE_BITMASK(dev, ABS, abs);
INPUT_CLEANSE_BITMASK(dev, MSC, msc);
INPUT_CLEANSE_BITMASK(dev, LED, led);
INPUT_CLEANSE_BITMASK(dev, SND, snd);
INPUT_CLEANSE_BITMASK(dev, FF, ff);
INPUT_CLEANSE_BITMASK(dev, SW, sw);
}
static void __input_unregister_device(struct input_dev *dev)
{
struct input_handle *handle, *next;
input_disconnect_device(dev);
mutex_lock(&input_mutex);
list_for_each_entry_safe(handle, next, &dev->h_list, d_node)
handle->handler->disconnect(handle);
WARN_ON(!list_empty(&dev->h_list));
del_timer_sync(&dev->timer);
list_del_init(&dev->node);
input_wakeup_procfs_readers();
mutex_unlock(&input_mutex);
device_del(&dev->dev);
}
static void devm_input_device_unregister(struct device *dev, void *res)
{
struct input_devres *devres = res;
struct input_dev *input = devres->input;
dev_dbg(dev, "%s: unregistering device %s\n",
__func__, dev_name(&input->dev));
__input_unregister_device(input);
}
struct input_dev *input_allocate_device(void)
{
static atomic_t input_no = ATOMIC_INIT(0);
struct input_dev *dev;
dev = kzalloc(sizeof(struct input_dev), GFP_KERNEL);// 注意GFP_KERNEL可能导致睡眠，不能在中断中调用这个函数
if (dev) {
dev->dev.type = &input_dev_type;
dev->dev.class = &input_class; //支持热插拔的结构体
device_initialize(&dev->dev);
mutex_init(&dev->mutex);
spin_lock_init(&dev->event_lock);
init_timer(&dev->timer);
INIT_LIST_HEAD(&dev->h_list);
INIT_LIST_HEAD(&dev->node);
dev_set_name(&dev->dev, "input%lu", // ???
(unsigned long) atomic_inc_return(&input_no) - 1);
__module_get(THIS_MODULE);
}
return dev;
}
EXPORT_SYMBOL(input_allocate_device);
int input_register_device(struct input_dev *dev)
{
struct input_devres *devres = NULL;
struct input_handler *handler;
unsigned int packet_size;
const char *path;
int error;
if (dev->devres_managed) {
devres = devres_alloc(devm_input_device_unregister,
sizeof(struct input_devres), GFP_KERNEL);
if (!devres)
return -ENOMEM;
devres->input = dev;
}
__set_bit(EV_SYN, dev->evbit); // 默认所有的输入设备都支持EV_SYN同步事件
/* KEY_RESERVED is not supposed to be transmitted to userspace. */
__clear_bit(KEY_RESERVED, dev->keybit);
/* Make sure that bitmasks not mentioned in dev->evbit are clean. */
input_cleanse_bitmasks(dev);
packet_size = input_estimate_events_per_packet(dev);
if (dev->hint_events_per_packet < packet_size)
dev->hint_events_per_packet = packet_size;
dev->max_vals = dev->hint_events_per_packet + 2;
dev->vals = kcalloc(dev->max_vals, sizeof(*dev->vals), GFP_KERNEL);
if (!dev->vals) {
error = -ENOMEM;
goto err_devres_free;
}
/*
如果设备驱动没有指定重复按键（连击），系统默认提供以下的支持
init_timer为连击产生的定时器，时间到调用input_repeat_key函数上报
REP_DELAY - 设置重复按键的键值
REP_PERIOD - 设置延时时间
*/
if (!dev->rep[REP_DELAY] && !dev->rep[REP_PERIOD]) {
dev->timer.data = (long) dev;
dev->timer.function = input_repeat_key;
dev->rep[REP_DELAY] = 250;
dev->rep[REP_PERIOD] = 33;
}
// 如果设备驱动没有设置自己的获取键值的函数，系统默认
if (!dev->getkeycode)
dev->getkeycode = input_default_getkeycode;
// 如果设备驱动没有指定按键重置函数，系统默认
if (!dev->setkeycode)
dev->setkeycode = input_default_setkeycode;
// 在/sys目录下创建设备目录和文件
error = device_add(&dev->dev);
if (error)
goto err_free_vals;
// 获取并打印设备的绝对路径名称
path = kobject_get_path(&dev->dev.kobj, GFP_KERNEL);
pr_info("%s as %s\n",
dev->name ? dev->name : "Unspecified device",
path ? path : "N/A");
kfree(path);
error = mutex_lock_interruptible(&input_mutex);
if (error)
goto err_device_del;
list_add_tail(&dev->node, &input_dev_list); // 重要，把设备挂到全局的input子设备链表input_dev_list上
/*
核心重点
遍历input_handler_list链表，链表中每一个handler(事件处理器)均尝试与dev(input子设备)匹配
匹配包括: 总线类型、供应商、生产id、版本id、驱动中配置的事件类型(abs、rel等)
匹配成功后返回id
注: input_register_handler() 与 input_register_device() 都会遍历链表 匹配
*/
list_for_each_entry(handler, &input_handler_list, node)
input_attach_handler(dev, handler);
input_wakeup_procfs_readers();
mutex_unlock(&input_mutex);
if (dev->devres_managed) {
dev_dbg(dev->dev.parent, "%s: registering %s with devres.\n",
__func__, dev_name(&dev->dev));
devres_add(dev->dev.parent, devres);
}
return 0;
err_device_del:
device_del(&dev->dev);
err_free_vals:
kfree(dev->vals);
dev->vals = NULL;
err_devres_free:
devres_free(devres);
return error;
}
EXPORT_SYMBOL(input_register_device);
static int input_attach_handler(struct input_dev *dev, struct input_handler *handler)
{
const struct input_device_id *id;
int error;
// 匹配成功后，将匹配上的handler(事件处理器)的id返回 -- 即找到最合适的事件处理器(tp用的evdev)
// 匹配handler->id_table[]中有标明的flag包括: 总线类型、供应商、生产id、版本id、驱动中配置的事件类型(abs、rel等)
// evdev 的id_table[] 为空，即和任何dev(input子设备)匹配
id = input_match_device(handler, dev);
if (!id)
return -ENODEV;
// 定义在 kernel-3.18/drivers/input/evdev.c
error = handler->connect(handler, dev, id);
if (error && error != -ENODEV)
pr_err("failed to attach handler %s to device %s, error: %d\n",
handler->name, kobject_name(&dev->dev.kobj), error);
return error;
}
static const struct input_device_id *input_match_device(struct input_handler *handler,
struct input_dev *dev)
{
const struct input_device_id *id;
// 如果handler->id_table中的flags、driver_info被设置，则进行匹配
// evdev 的id_table[] 为空，即和任何dev(input子设备)匹配
for (id = handler->id_table; id->flags || id->driver_info; id++) {
if (id->flags & INPUT_DEVICE_ID_MATCH_BUS)// 如果flag中INPUT_DEVICE_ID_MATCH_BUS位被设置
if (id->bustype != dev->id.bustype) // 匹配总线类型
continue;
if (id->flags & INPUT_DEVICE_ID_MATCH_VENDOR)
if (id->vendor != dev->id.vendor) // 匹配供应商
continue;
if (id->flags & INPUT_DEVICE_ID_MATCH_PRODUCT)
if (id->product != dev->id.product) // 匹配生产id
continue;
if (id->flags & INPUT_DEVICE_ID_MATCH_VERSION)
if (id->version != dev->id.version) // 匹配版本id
continue;
// 如果前面都匹配上了，接着进行匹配我们在驱动中设置的事件类型
if (!bitmap_subset(id->evbit, dev->evbit, EV_MAX))
continue;
if (!bitmap_subset(id->keybit, dev->keybit, KEY_MAX))
continue;
if (!bitmap_subset(id->relbit, dev->relbit, REL_MAX))
continue;
if (!bitmap_subset(id->absbit, dev->absbit, ABS_MAX))
continue;
if (!bitmap_subset(id->mscbit, dev->mscbit, MSC_MAX))
continue;
if (!bitmap_subset(id->ledbit, dev->ledbit, LED_MAX))
continue;
if (!bitmap_subset(id->sndbit, dev->sndbit, SND_MAX))
continue;
if (!bitmap_subset(id->ffbit, dev->ffbit, FF_MAX))
continue;
if (!bitmap_subset(id->swbit, dev->swbit, SW_MAX))
continue;
if (!handler->match || handler->match(handler, dev))
return id; // 上述匹配均符合，则返回id
}
return NULL;
}
/**
* input_unregister_device - unregister previously registered device
* @dev: device to be unregistered
*
* This function unregisters an input device. Once device is unregistered
* the caller should not try to access it as it may get freed at any moment.
*/
void input_unregister_device(struct input_dev *dev)
{
if (dev->devres_managed) {
WARN_ON(devres_destroy(dev->dev.parent,
devm_input_device_unregister,
devm_input_device_match,
dev));
__input_unregister_device(dev);
/*
* We do not do input_put_device() here because it will be done
* when 2nd devres fires up.
*/
} else {
__input_unregister_device(dev);
input_put_device(dev);
}
}
EXPORT_SYMBOL(input_unregister_device);
// kernel-3.18/drivers/input/evdev.c 中 evdev_init() -- module_init()
int input_register_handler(struct input_handler *handler)
{
struct input_dev *dev;
int error;
error = mutex_lock_interruptible(&input_mutex);
if (error)
return error;
INIT_LIST_HEAD(&handler->h_list);
// 重要，把设备挂到全局的事件处理器链表input_handler_list上
list_add_tail(&handler->node, &input_handler_list);
/*
核心重点
遍历input_dev_list链表，链表中每一个dev均尝试与handler(事件处理器)匹配
匹配包括: 总线类型、供应商、生产id、版本id、驱动中配置的事件类型(abs、rel等)
匹配成功后返回id
注: input_register_handler() 与 input_register_device() 都会遍历链表 匹配
*/
list_for_each_entry(dev, &input_dev_list, node)
input_attach_handler(dev, handler);
input_wakeup_procfs_readers();
mutex_unlock(&input_mutex);
return 0;
}
EXPORT_SYMBOL(input_register_handler);
/**
* input_unregister_handler - unregisters an input handler
* @handler: handler to be unregistered
*
* This function disconnects a handler from its input devices and
* removes it from lists of known handlers.
*/
void input_unregister_handler(struct input_handler *handler)
{
struct input_handle *handle, *next;
mutex_lock(&input_mutex);
list_for_each_entry_safe(handle, next, &handler->h_list, h_node)
handler->disconnect(handle);
WARN_ON(!list_empty(&handler->h_list));
list_del_init(&handler->node);
input_wakeup_procfs_readers();
mutex_unlock(&input_mutex);
}
EXPORT_SYMBOL(input_unregister_handler);
/**
* input_handler_for_each_handle - handle iterator
* @handler: input handler to iterate
* @data: data for the callback
* @fn: function to be called for each handle
*
* Iterate over @bus's list of devices, and call @fn for each, passing
* it @data and stop when @fn returns a non-zero value. The function is
* using RCU to traverse the list and therefore may be usind in atonic
* contexts. The @fn callback is invoked from RCU critical section and
* thus must not sleep.
*/
int input_handler_for_each_handle(struct input_handler *handler, void *data,
int (*fn)(struct input_handle *, void *))
{
struct input_handle *handle;
int retval = 0;
rcu_read_lock();
list_for_each_entry_rcu(handle, &handler->h_list, h_node) {
retval = fn(handle, data);
if (retval)
break;
}
rcu_read_unlock();
return retval;
}
EXPORT_SYMBOL(input_handler_for_each_handle);
/**
* input_register_handle - register a new input handle
* @handle: handle to register
*
* This function puts a new input handle onto device's
* and handler's lists so that events can flow through
* it once it is opened using input_open_device().
*
* This function is supposed to be called from handler's
* connect() method.
*/
int input_register_handle(struct input_handle *handle)
{
struct input_handler *handler = handle->handler;
struct input_dev *dev = handle->dev;
int error;
/*
* We take dev->mutex here to prevent race with
* input_release_device().
*/
error = mutex_lock_interruptible(&dev->mutex);
if (error)
return error;
/*
* Filters go to the head of the list, normal handlers
* to the tail.
*/
if (handler->filter)
list_add_rcu(&handle->d_node, &dev->h_list);
else
list_add_tail_rcu(&handle->d_node, &dev->h_list);
mutex_unlock(&dev->mutex);
/*
* Since we are supposed to be called from ->connect()
* which is mutually exclusive with ->disconnect()
* we can't be racing with input_unregister_handle()
* and so separate lock is not needed here.
*/
list_add_tail_rcu(&handle->h_node, &handler->h_list);
if (handler->start)
handler->start(handle);
return 0;
}
EXPORT_SYMBOL(input_register_handle);
/**
* input_unregister_handle - unregister an input handle
* @handle: handle to unregister
*
* This function removes input handle from device's
* and handler's lists.
*
* This function is supposed to be called from handler's
* disconnect() method.
*/
void input_unregister_handle(struct input_handle *handle)
{
struct input_dev *dev = handle->dev;
list_del_rcu(&handle->h_node);
/*
* Take dev->mutex to prevent race with input_release_device().
*/
mutex_lock(&dev->mutex);
list_del_rcu(&handle->d_node);
mutex_unlock(&dev->mutex);
synchronize_rcu();
}
EXPORT_SYMBOL(input_unregister_handle);
/**
* input_get_new_minor - allocates a new input minor number
* @legacy_base: beginning or the legacy range to be searched
* @legacy_num: size of legacy range
* @allow_dynamic: whether we can also take ID from the dynamic range
*
* This function allocates a new device minor for from input major namespace.
* Caller can request legacy minor by specifying @legacy_base and @legacy_num
* parameters and whether ID can be allocated from dynamic range if there are
* no free IDs in legacy range.
*/
int input_get_new_minor(int legacy_base, unsigned int legacy_num,
bool allow_dynamic)
{
/*
* This function should be called from input handler's ->connect()
* methods, which are serialized with input_mutex, so no additional
* locking is needed here.
*/
if (legacy_base >= 0) {
int minor = ida_simple_get(&input_ida,
legacy_base,
legacy_base + legacy_num,
GFP_KERNEL);
if (minor >= 0 || !allow_dynamic)
return minor;
}
return ida_simple_get(&input_ida,
INPUT_FIRST_DYNAMIC_DEV, INPUT_MAX_CHAR_DEVICES,
GFP_KERNEL);
}
EXPORT_SYMBOL(input_get_new_minor);
/**
* input_free_minor - release previously allocated minor
* @minor: minor to be released
*
* This function releases previously allocated input minor so that it can be
* reused later.
*/
void input_free_minor(unsigned int minor)
{
ida_simple_remove(&input_ida, minor);
}
EXPORT_SYMBOL(input_free_minor);
static int __init input_init(void)
{
int err;
// 与class_create()类似，内部都调用__class_register()
// 将class注册到内核中，同时创建/sys/class/下节点
err = class_register(&input_class);
if (err) {
pr_err("unable to register input_dev class\n");
return err;
}
err = input_proc_init();
if (err)
goto fail1;
// 根据要求申请主设备号，主设备号INPUT_MAJOR == 13
err = register_chrdev_region(MKDEV(INPUT_MAJOR, 0),
INPUT_MAX_CHAR_DEVICES, "input");
if (err) {
pr_err("unable to register char major %d", INPUT_MAJOR);
goto fail2;
}
return 0;
fail2: input_proc_exit();
fail1: class_unregister(&input_class);
return err;
}
static void __exit input_exit(void)
{
input_proc_exit();
unregister_chrdev_region(MKDEV(INPUT_MAJOR, 0),
INPUT_MAX_CHAR_DEVICES);
class_unregister(&input_class);
}
subsys_initcall(input_init);
module_exit(input_exit);
';
sscanf(buf, "%d\n", &num);
sprintf(buf_s, "/dev/input/event%d", num);
fd = open(buf_s, O_RDONLY);
readEvents()
mInputReader.fill(mdata_fd)
mInputReader.readEvent(&event)
即open("/dev/input/event%d", O_RDONLY);
-----------------------------------------
vfs
sys_open(); // 系统调用
struct file file->f_ops = cdev->ops;
file->f_ops->open();
-----------------------------------------
input handler层: evdev.c
cdev
xxx_ops = {
.open = xxx_open,
.read = xxx_read,
}
evdev_connect()
cdev_init(&evdev->cdev, &evdev_fops);
static const struct file_operations evdev_fops = {
.owner = THIS_MODULE,
.read = evdev_read,
.write = evdev_write,
.poll = evdev_poll,
.open = evdev_open,
};
实际上最终调用了evdev_open()
evdev_open(struct inode *inode, struct file *file)
|
struct evdev *evdev = container_of(inode->i_cdev, struct evdev, cdev); // 以小博大，inode->i_cdev就是connect()中住的的cdev
unsigned int bufsize = evdev_compute_buffer_size(evdev->handle.dev); // 通过handle找到 input device，根据input device 获取缓冲区的大小(几个input event)，但是我们驱动中未给定缓冲区大小，系统会自动给定一个
unsigned int size = sizeof(struct evdev_client) + // size包含了很多个input event
bufsize * sizeof(struct input_event);
struct evdev_client *client;
client = kzalloc(size, GFP_KERNEL | __GFP_NOWARN); // 分配一个client对象，用来描述一个缓冲队列，存放的就是input_event
client->bufsize = bufsize; // client中有一个缓冲区
spin_lock_init(&client->buffer_lock);
client->evdev = evdev; // evdev_client中记录evdev
evdev_attach_client(evdev, client); // 将client 加入到evdev中的一个小链表中
|
list_add_tail_rcu(&client->node, &evdev->client_list);
file->private_data = client; // evdev_client记录到file中，方便其他接口调用(这里是open()，其他接口还有read()、write())
总结:
1. 为输入设备分配一个缓冲区evdev_client，用于存放input device层上报的数据
2. evdev_client中记录evdev
3. evdev_client记录到file中，方便其他read() write() 等接口使用
==============================================
2.应用程序调用read()
read(fd, &event, sizeof(struct input_event));
-----------------------------------------
vfs
sys_read(); // 系统调用
file->f_ops->read(); // fd就是file数组的下表，通过传入的fd找到file，其中的f_ops在open()的时候已经获取并保存
-----------------------------------------
static ssize_t evdev_read(struct file *file, char __user *buffer, size_t count, loff_t *ppos)
|
struct evdev_client *client = file->private_data; // 获取open() 分配的缓冲区
struct evdev *evdev = client->evdev; // 获取到evdev
struct input_event event; // 表示一个数据包，要给用户
for (;;) {
// 实现非阻塞 -- 队列为空，且为非阻塞模式，直接返回again
if (client->packet_head == client->tail && // 队列的头跟尾位置一样 == 队列为空
(file->f_flags & O_NONBLOCK)) // 非阻塞
return -EAGAIN;
// while每循环一次取一个input event数据，read加1
while (read + input_event_size() <= count && // 这里判断要取的数据个数是否已取ok，count是要取得数据个数
evdev_fetch_next_event(client, &event)) { // 1. 从client的缓冲区取数据，放到event中
|
*event = client->buffer[client->tail++];// 将client->buffer[]队列的尾巴给*event
if (input_event_to_user(buffer + read, &event)) // 2. 把数据给用户空间
|
copy_from_user(event, buffer, sizeof(struct input_event))
read += input_event_size(); // 3. 统计上报多少数据
}
if (!(file->f_flags & O_NONBLOCK)) { // 如果当前不是非阻塞模式，即阻塞模式
error = wait_event_interruptible(evdev->wait, // 休眠 - 条件不满足就睡眠:
client->packet_head != client->tail || // 队列头不等于尾 -> 有数据
!evdev->exist || client->revoked);
总结:
1. 如果没数据，就休眠等待
2. 如果有数据，就会从缓冲区client->buffer[client->tail++]拿数据，通过copy_to_user上报给用户
疑问:
1. 数据到底是如何存放在缓冲区的
2. 等待队列是谁唤醒的
==============================================
3. 上报流程:
input_report_abs(gt811_dev->input, ABS_MT_POSITION_X, x);
input_report_abs(gt811_dev->input, ABS_MT_POSITION_Y, y);
input_mt_sync(gt811_dev->input);
input_report_abs(struct input_dev *dev, unsigned int code, int value)
|
input_event(dev, EV_ABS, code, value);
|
input_handle_event(dev, type, code, value);
|
if (disposition & INPUT_PASS_TO_HANDLERS) { // input device数据交给input handler处理
struct input_value *v;
v = &dev->vals[dev->num_vals++]; // 将input device获取到的数据暂存到dev->vals
v->type = type;
v->code = code;
v->value = value;
input_pass_values(dev, dev->vals, dev->num_vals);
|
list_for_each_entry_rcu(handle, &dev->h_list, d_node) // 通过inpit device中与handle建立连接的 h_list 成员找到 handle
if (handle->open)
input_to_handler(handle, vals, count);
|
struct input_handler *handler = handle->handler; // 通过出入的handle找到input handler(这里是evdev)
if (handler->events) // 首选events()， 没有才调用event()
handler->events(handle, vals, count); // 调用events()
else if (handler->event)
for (v = vals; v != end; v++)
handler->event(handle, v->type, v->code, v->value);
static struct input_handler evdev_handler = {
.event = evdev_event,
.events = evdev_events,
.connect = evdev_connect,
.disconnect = evdev_disconnect,
.legacy_minors = true,
.minor = EVDEV_MINOR_BASE,
.name = "evdev",
.id_table = evdev_ids,
};
static void evdev_events(struct input_handle *handle, const struct input_value *vals, unsigned int count)
|
struct evdev *evdev = handle->private; // 从handle中拿到evdev -- connect()中保存了:evdev->handle.private = evdev;
struct evdev_client *client;
如果多个应用进程打开了同一个input device, 每次open()都会生成一个evdev_client
evdev_client挂载到evdev的client_list链表中
input_report_abs()时，handler会把数据copy到client_list所有的evdev_client的buffer中
input_mt_sync()，逐一唤醒
list_for_each_entry_rcu(client, &evdev->client_list, node)
evdev_pass_values(client, vals, count, time_mono, time_real);
|
struct evdev *evdev = client->evdev; // 通过client 获取到 evdev
const struct input_value *v;
struct input_event event; // 数据包
event.time = ktime_to_timeval(client->clkid == CLOCK_MONOTONIC ? mono : real); // 填充数据包中的时间戳
for (v = vals; v != vals + count; v++) { // 将input device上报的数据封装成 input_event对象
event.type = v->type;
event.code = v->code;
event.value = v->value;
__pass_event(client, &event); // 将input event数据放在缓冲区的头部 -- 读的时候从尾巴开始读
|
client->buffer[client->head++] = *event; // 将input event数据放入缓冲区
client->head &= client->bufsize - 1;
if (v->type == EV_SYN && v->code == SYN_REPORT) // 唤醒等待队列 -- 如果调用了input_sync() -- input_event(dev, EV_SYN, SYN_REPORT, 0);
wakeup = true;
}
if (wakeup) // 唤醒等待队列
wake_up_interruptible(&evdev->wait);
struct input_event {
struct timeval time;
__u16 type; // 如:EV_ABS
__u16 code; // 如:ABS_MT_POSITION_X
__s32 value; // 如:x (具体的数值，这里是tp横坐标)
};
总结:
1. 数据到底是如何存放在缓冲区的
input_report_abs()将数据交给handler，调用events()，将数据放入缓冲区client->buffer[client->head++] = *event;
2. 等待队列是谁唤醒的
input_mt_sync() 显式唤醒等待队列 wake_up_interruptible(&evdev->wait);
*/
/*
字符设备注册流程
register_chrdev_region(MKDEV(major, 0), 1, "hello");
cdev_init(&hello_cdev, &hello_fops);
cdev_add(&hello_cdev, devid, 1);
cls = class_create(THIS_MODULE, "hello"); // 等同class_register()
dev = device_create(cls, NULL, MKDEV(major, 0), NULL, "hello")
*/
#define pr_fmt(fmt) KBUILD_BASENAME ": " fmt
#include <linux/init.h>
#include <linux/types.h>
#include <linux/idr.h>
#include <linux/input/mt.h>
#include <linux/module.h>
#include <linux/slab.h>
#include <linux/random.h>
#include <linux/major.h>
#include <linux/proc_fs.h>
#include <linux/sched.h>
#include <linux/seq_file.h>
#include <linux/poll.h>
#include <linux/device.h>
#include <linux/mutex.h>
#include <linux/rcupdate.h>
#include "input-compat.h"
MODULE_AUTHOR("Vojtech Pavlik <[email protected]>");
MODULE_DESCRIPTION("Input core");
MODULE_LICENSE("GPL");
#define INPUT_MAX_CHAR_DEVICES 1024
#define INPUT_FIRST_DYNAMIC_DEV 256
static DEFINE_IDA(input_ida);
static LIST_HEAD(input_dev_list);
static LIST_HEAD(input_handler_list);
/*
* input_mutex protects access to both input_dev_list and input_handler_list.
* This also causes input_[un]register_device and input_[un]register_handler
* be mutually exclusive which simplifies locking in drivers implementing
* input handlers.
*/
static DEFINE_MUTEX(input_mutex);
static const struct input_value input_value_sync = { EV_SYN, SYN_REPORT, 1 };
static inline int is_event_supported(unsigned int code,
unsigned long *bm, unsigned int max)
{
return code <= max && test_bit(code, bm);
}
static int input_defuzz_abs_event(int value, int old_val, int fuzz)
{
if (fuzz) {
if (value > old_val - fuzz / 2 && value < old_val + fuzz / 2)
return old_val;
if (value > old_val - fuzz && value < old_val + fuzz)
return (old_val * 3 + value) / 4;
if (value > old_val - fuzz * 2 && value < old_val + fuzz * 2)
return (old_val + value) / 2;
}
return value;
}
static void input_start_autorepeat(struct input_dev *dev, int code)
{
if (test_bit(EV_REP, dev->evbit) &&
dev->rep[REP_PERIOD] && dev->rep[REP_DELAY] &&
dev->timer.data) {
dev->repeat_key = code;
mod_timer(&dev->timer,
jiffies + msecs_to_jiffies(dev->rep[REP_DELAY]));
}
}
static void input_stop_autorepeat(struct input_dev *dev)
{
del_timer(&dev->timer);
}
/*
* Pass event first through all filters and then, if event has not been
* filtered out, through all open handles. This function is called with
* dev->event_lock held and interrupts disabled.
*/
static unsigned int input_to_handler(struct input_handle *handle,
struct input_value *vals, unsigned int count)
{
// 通过handle找到handler
struct input_handler *handler = handle->handler;
struct input_value *end = vals;
struct input_value *v;
for (v = vals; v != vals + count; v++) {
if (handler->filter && // 如果有过滤器，运行过滤，事实上没有
handler->filter(handle, v->type, v->code, v->value))
continue;
if (end != v)
*end = *v;
end++;
}
count = end - vals;
if (!count)
return 0;
// 调用events() 或 event() -- 数据暂存vals
if (handler->events)
handler->events(handle, vals, count); // 首选events()， 没有才调用event()
else if (handler->event)
for (v = vals; v != end; v++)
handler->event(handle, v->type, v->code, v->value);
return count;
}
/*
* Pass values first through all filters and then, if event has not been
* filtered out, through all open handles. This function is called with
* dev->event_lock held and interrupts disabled.
*/
static void input_pass_values(struct input_dev *dev,
struct input_value *vals, unsigned int count) // 数据暂存在vals
{
struct input_handle *handle;
struct input_value *v;
if (!count)
return;
rcu_read_lock();
// 从input device中获取到input handle
handle = rcu_dereference(dev->grab);
if (handle) {
count = input_to_handler(handle, vals, count);
}
// 走这里
else {
list_for_each_entry_rcu(handle, &dev->h_list, d_node)
if (handle->open)
count = input_to_handler(handle, vals, count);
}
rcu_read_unlock();
add_input_randomness(vals->type, vals->code, vals->value);
/* trigger auto repeat for key events */
for (v = vals; v != vals + count; v++) {
if (v->type == EV_KEY && v->value != 2) {
if (v->value)
input_start_autorepeat(dev, v->code);
else
input_stop_autorepeat(dev);
}
}
}
static void input_pass_event(struct input_dev *dev,
unsigned int type, unsigned int code, int value)
{
struct input_value vals[] = { { type, code, value } };
input_pass_values(dev, vals, ARRAY_SIZE(vals));
}
/*
* Generate software autorepeat event. Note that we take
* dev->event_lock here to avoid racing with input_event
* which may cause keys get "stuck".
*/
static void input_repeat_key(unsigned long data)
{
struct input_dev *dev = (void *) data;
unsigned long flags;
spin_lock_irqsave(&dev->event_lock, flags);
if (test_bit(dev->repeat_key, dev->key) &&
is_event_supported(dev->repeat_key, dev->keybit, KEY_MAX)) {
struct input_value vals[] = {
{ EV_KEY, dev->repeat_key, 2 },
input_value_sync
};
input_pass_values(dev, vals, ARRAY_SIZE(vals));
if (dev->rep[REP_PERIOD])
mod_timer(&dev->timer, jiffies +
msecs_to_jiffies(dev->rep[REP_PERIOD]));
}
spin_unlock_irqrestore(&dev->event_lock, flags);
}
#define INPUT_IGNORE_EVENT 0
#define INPUT_PASS_TO_HANDLERS 1
#define INPUT_PASS_TO_DEVICE 2
#define INPUT_SLOT 4
#define INPUT_FLUSH 8
#define INPUT_PASS_TO_ALL (INPUT_PASS_TO_HANDLERS | INPUT_PASS_TO_DEVICE)
static int input_handle_abs_event(struct input_dev *dev,
unsigned int code, int *pval)
{
struct input_mt *mt = dev->mt;
bool is_mt_event;
int *pold;
if (code == ABS_MT_SLOT) {
/*
* "Stage" the event; we'll flush it later, when we
* get actual touch data.
*/
if (mt && *pval >= 0 && *pval < mt->num_slots)
mt->slot = *pval;
return INPUT_IGNORE_EVENT;
}
is_mt_event = input_is_mt_value(code);
if (!is_mt_event) {
pold = &dev->absinfo[code].value;
} else if (mt) {
pold = &mt->slots[mt->slot].abs[code - ABS_MT_FIRST];
} else {
/*
* Bypass filtering for multi-touch events when
* not employing slots.
*/
pold = NULL;
}
if (pold) {
*pval = input_defuzz_abs_event(*pval, *pold,
dev->absinfo[code].fuzz);
if (*pold == *pval)
return INPUT_IGNORE_EVENT;
*pold = *pval;
}
/* Flush pending "slot" event */
if (is_mt_event && mt && mt->slot != input_abs_get_val(dev, ABS_MT_SLOT)) {
input_abs_set_val(dev, ABS_MT_SLOT, mt->slot);
return INPUT_PASS_TO_HANDLERS | INPUT_SLOT;
}
return INPUT_PASS_TO_HANDLERS;
}
static int input_get_disposition(struct input_dev *dev,
unsigned int type, unsigned int code, int *pval)
{
int disposition = INPUT_IGNORE_EVENT;
int value = *pval;
switch (type) {
case EV_SYN:
switch (code) {
case SYN_CONFIG:
disposition = INPUT_PASS_TO_ALL;
break;
case SYN_REPORT:
disposition = INPUT_PASS_TO_HANDLERS | INPUT_FLUSH;
break;
case SYN_MT_REPORT:
disposition = INPUT_PASS_TO_HANDLERS;
break;
}
break;
case EV_KEY:
if (is_event_supported(code, dev->keybit, KEY_MAX)) {
/* auto-repeat bypasses state updates */
if (value == 2) {
disposition = INPUT_PASS_TO_HANDLERS;
break;
}
if (!!test_bit(code, dev->key) != !!value) {
__change_bit(code, dev->key);
disposition = INPUT_PASS_TO_HANDLERS;
}
}
break;
case EV_SW:
if (is_event_supported(code, dev->swbit, SW_MAX) &&
!!test_bit(code, dev->sw) != !!value) {
__change_bit(code, dev->sw);
disposition = INPUT_PASS_TO_HANDLERS;
}
break;
case EV_ABS:
if (is_event_supported(code, dev->absbit, ABS_MAX))
disposition = input_handle_abs_event(dev, code, &value);
break;
case EV_REL:
if (is_event_supported(code, dev->relbit, REL_MAX) && value)
disposition = INPUT_PASS_TO_HANDLERS;
break;
case EV_MSC:
if (is_event_supported(code, dev->mscbit, MSC_MAX))
disposition = INPUT_PASS_TO_ALL;
break;
case EV_LED:
if (is_event_supported(code, dev->ledbit, LED_MAX) &&
!!test_bit(code, dev->led) != !!value) {
__change_bit(code, dev->led);
disposition = INPUT_PASS_TO_ALL;
}
break;
case EV_SND:
if (is_event_supported(code, dev->sndbit, SND_MAX)) {
if (!!test_bit(code, dev->snd) != !!value)
__change_bit(code, dev->snd);
disposition = INPUT_PASS_TO_ALL;
}
break;
case EV_REP:
if (code <= REP_MAX && value >= 0 && dev->rep[code] != value) {
dev->rep[code] = value;
disposition = INPUT_PASS_TO_ALL;
}
break;
case EV_FF:
if (value >= 0)
disposition = INPUT_PASS_TO_ALL;
break;
case EV_PWR:
disposition = INPUT_PASS_TO_ALL;
break;
}
*pval = value;
return disposition;
}
static void input_handle_event(struct input_dev *dev,
unsigned int type, unsigned int code, int value)
{
int disposition;
disposition = input_get_disposition(dev, type, code, &value);
if ((disposition & INPUT_PASS_TO_DEVICE) && dev->event) // 【少用】input device数据交给自己的evdev处理，且有自己的evdev，调用自己的evdev处理
dev->event(dev, type, code, value);
if (!dev->vals)
return;
if (disposition & INPUT_PASS_TO_HANDLERS) { // input device数据交给input handler处理
struct input_value *v;
if (disposition & INPUT_SLOT) {
v = &dev->vals[dev->num_vals++];
v->type = EV_ABS;
v->code = ABS_MT_SLOT;
v->value = dev->mt->slot;
}
// 将input device获取到的数据暂存到dev->vals
v = &dev->vals[dev->num_vals++];
v->type = type;
v->code = code;
v->value = value;
}
if (disposition & INPUT_FLUSH) {
if (dev->num_vals >= 2)
input_pass_values(dev, dev->vals, dev->num_vals);
dev->num_vals = 0;
} else if (dev->num_vals >= dev->max_vals - 2) {
dev->vals[dev->num_vals++] = input_value_sync;
input_pass_values(dev, dev->vals, dev->num_vals);
dev->num_vals = 0;
}
}
/**
* input_event() - report new input event
* @dev: device that generated the event
* @type: type of the event
* @code: event code
* @value: value of the event
*
* This function should be used by drivers implementing various input
* devices to report input events. See also input_inject_event().
*
* NOTE: input_event() may be safely used right after input device was
* allocated with input_allocate_device(), even before it is registered
* with input_register_device(), but the event will not reach any of the
* input handlers. Such early invocation of input_event() may be used
* to 'seed' initial state of a switch or initial position of absolute
* axis, etc.
*/
void input_event(struct input_dev *dev,
unsigned int type, unsigned int code, int value)
{
unsigned long flags;
if (is_event_supported(type, dev->evbit, EV_MAX)) { // type : EV_ABS, 判断dev->evbit中是否使能该type
spin_lock_irqsave(&dev->event_lock, flags); // 自旋锁 - 屏蔽多cpu抢占， irqsave - 屏蔽中断抢占
input_handle_event(dev, type, code, value);
spin_unlock_irqrestore(&dev->event_lock, flags);
}
}
EXPORT_SYMBOL(input_event);
/**
* input_inject_event() - send input event from input handler
* @handle: input handle to send event through
* @type: type of the event
* @code: event code
* @value: value of the event
*
* Similar to input_event() but will ignore event if device is
* "grabbed" and handle injecting event is not the one that owns
* the device.
*/
void input_inject_event(struct input_handle *handle,
unsigned int type, unsigned int code, int value)
{
struct input_dev *dev = handle->dev;
struct input_handle *grab;
unsigned long flags;
if (is_event_supported(type, dev->evbit, EV_MAX)) {
spin_lock_irqsave(&dev->event_lock, flags);
rcu_read_lock();
grab = rcu_dereference(dev->grab);
if (!grab || grab == handle)
input_handle_event(dev, type, code, value);
rcu_read_unlock();
spin_unlock_irqrestore(&dev->event_lock, flags);
}
}
EXPORT_SYMBOL(input_inject_event);
/**
* input_alloc_absinfo - allocates array of input_absinfo structs
* @dev: the input device emitting absolute events
*
* If the absinfo struct the caller asked for is already allocated, this
* functions will not do anything.
*/
void input_alloc_absinfo(struct input_dev *dev)
{
if (!dev->absinfo)
dev->absinfo = kcalloc(ABS_CNT, sizeof(struct input_absinfo),
GFP_KERNEL);
WARN(!dev->absinfo, "%s(): kcalloc() failed?\n", __func__);
}
EXPORT_SYMBOL(input_alloc_absinfo);
void input_set_abs_params(struct input_dev *dev, unsigned int axis,
int min, int max, int fuzz, int flat)
{
struct input_absinfo *absinfo;
input_alloc_absinfo(dev);
if (!dev->absinfo)
return;
absinfo = &dev->absinfo[axis];
absinfo->minimum = min;
absinfo->maximum = max;
absinfo->fuzz = fuzz;
absinfo->flat = flat;
__set_bit(EV_ABS, dev->evbit);
__set_bit(axis, dev->absbit);
}
EXPORT_SYMBOL(input_set_abs_params);
/**
* input_grab_device - grabs device for exclusive use
* @handle: input handle that wants to own the device
*
* When a device is grabbed by an input handle all events generated by
* the device are delivered only to this handle. Also events injected
* by other input handles are ignored while device is grabbed.
*/
int input_grab_device(struct input_handle *handle)
{
struct input_dev *dev = handle->dev;
int retval;
retval = mutex_lock_interruptible(&dev->mutex);
if (retval)
return retval;
if (dev->grab) {
retval = -EBUSY;
goto out;
}
rcu_assign_pointer(dev->grab, handle);
out:
mutex_unlock(&dev->mutex);
return retval;
}
EXPORT_SYMBOL(input_grab_device);
static void __input_release_device(struct input_handle *handle)
{
struct input_dev *dev = handle->dev;
struct input_handle *grabber;
grabber = rcu_dereference_protected(dev->grab,
lockdep_is_held(&dev->mutex));
if (grabber == handle) {
rcu_assign_pointer(dev->grab, NULL);
/* Make sure input_pass_event() notices that grab is gone */
synchronize_rcu();
list_for_each_entry(handle, &dev->h_list, d_node)
if (handle->open && handle->handler->start)
handle->handler->start(handle);
}
}
/**
* input_release_device - release previously grabbed device
* @handle: input handle that owns the device
*
* Releases previously grabbed device so that other input handles can
* start receiving input events. Upon release all handlers attached
* to the device have their start() method called so they have a change
* to synchronize device state with the rest of the system.
*/
void input_release_device(struct input_handle *handle)
{
struct input_dev *dev = handle->dev;
mutex_lock(&dev->mutex);
__input_release_device(handle);
mutex_unlock(&dev->mutex);
}
EXPORT_SYMBOL(input_release_device);
/**
* input_open_device - open input device
* @handle: handle through which device is being accessed
*
* This function should be called by input handlers when they
* want to start receive events from given input device.
*/
int input_open_device(struct input_handle *handle)
{
struct input_dev *dev = handle->dev;
int retval;
retval = mutex_lock_interruptible(&dev->mutex);
if (retval)
return retval;
if (dev->going_away) {
retval = -ENODEV;
goto out;
}
handle->open++;
if (!dev->users++ && dev->open)
retval = dev->open(dev);
if (retval) {
dev->users--;
if (!--handle->open) {
/*
* Make sure we are not delivering any more events
* through this handle
*/
synchronize_rcu();
}
}
out:
mutex_unlock(&dev->mutex);
return retval;
}
EXPORT_SYMBOL(input_open_device);
int input_flush_device(struct input_handle *handle, struct file *file)
{
struct input_dev *dev = handle->dev;
int retval;
retval = mutex_lock_interruptible(&dev->mutex);
if (retval)
return retval;
if (dev->flush)
retval = dev->flush(dev, file);
mutex_unlock(&dev->mutex);
return retval;
}
EXPORT_SYMBOL(input_flush_device);
/**
* input_close_device - close input device
* @handle: handle through which device is being accessed
*
* This function should be called by input handlers when they
* want to stop receive events from given input device.
*/
void input_close_device(struct input_handle *handle)
{
struct input_dev *dev = handle->dev;
mutex_lock(&dev->mutex);
__input_release_device(handle);
if (!--dev->users && dev->close)
dev->close(dev);
if (!--handle->open) {
/*
* synchronize_rcu() makes sure that input_pass_event()
* completed and that no more input events are delivered
* through this handle
*/
synchronize_rcu();
}
mutex_unlock(&dev->mutex);
}
EXPORT_SYMBOL(input_close_device);
/*
* Simulate keyup events for all keys that are marked as pressed.
* The function must be called with dev->event_lock held.
*/
static void input_dev_release_keys(struct input_dev *dev)
{
int code;
bool need_sync = false;
if (is_event_supported(EV_KEY, dev->evbit, EV_MAX)) {
for (code = 0; code <= KEY_MAX; code++) {
if (is_event_supported(code, dev->keybit, KEY_MAX) &&
__test_and_clear_bit(code, dev->key)) {
input_pass_event(dev, EV_KEY, code, 0);
need_sync = true;
}
}
if (need_sync)
input_pass_event(dev, EV_SYN, SYN_REPORT, 1);
}
}
/*
* Prepare device for unregistering
*/
static void input_disconnect_device(struct input_dev *dev)
{
struct input_handle *handle;
/*
* Mark device as going away. Note that we take dev->mutex here
* not to protect access to dev->going_away but rather to ensure
* that there are no threads in the middle of input_open_device()
*/
mutex_lock(&dev->mutex);
dev->going_away = true;
mutex_unlock(&dev->mutex);
spin_lock_irq(&dev->event_lock);
/*
* Simulate keyup events for all pressed keys so that handlers
* are not left with "stuck" keys. The driver may continue
* generate events even after we done here but they will not
* reach any handlers.
*/
input_dev_release_keys(dev);
list_for_each_entry(handle, &dev->h_list, d_node)
handle->open = 0;
spin_unlock_irq(&dev->event_lock);
}
/**
* input_scancode_to_scalar() - converts scancode in &struct input_keymap_entry
* @ke: keymap entry containing scancode to be converted.
* @scancode: pointer to the location where converted scancode should
* be stored.
*
* This function is used to convert scancode stored in &struct keymap_entry
* into scalar form understood by legacy keymap handling methods. These
* methods expect scancodes to be represented as 'unsigned int'.
*/
int input_scancode_to_scalar(const struct input_keymap_entry *ke,
unsigned int *scancode)
{
switch (ke->len) {
case 1:
*scancode = *((u8 *)ke->scancode);
break;
case 2:
*scancode = *((u16 *)ke->scancode);
break;
case 4:
*scancode = *((u32 *)ke->scancode);
break;
default:
return -EINVAL;
}
return 0;
}
EXPORT_SYMBOL(input_scancode_to_scalar);
/*
* Those routines handle the default case where no [gs]etkeycode() is
* defined. In this case, an array indexed by the scancode is used.
*/
static unsigned int input_fetch_keycode(struct input_dev *dev,
unsigned int index)
{
switch (dev->keycodesize) {
case 1:
return ((u8 *)dev->keycode)[index];
case 2:
return ((u16 *)dev->keycode)[index];
default:
return ((u32 *)dev->keycode)[index];
}
}
static int input_default_getkeycode(struct input_dev *dev,
struct input_keymap_entry *ke)
{
unsigned int index;
int error;
if (!dev->keycodesize)
return -EINVAL;
if (ke->flags & INPUT_KEYMAP_BY_INDEX)
index = ke->index;
else {
error = input_scancode_to_scalar(ke, &index);
if (error)
return error;
}
if (index >= dev->keycodemax)
return -EINVAL;
ke->keycode = input_fetch_keycode(dev, index);
ke->index = index;
ke->len = sizeof(index);
memcpy(ke->scancode, &index, sizeof(index));
return 0;
}
static int input_default_setkeycode(struct input_dev *dev,
const struct input_keymap_entry *ke,
unsigned int *old_keycode)
{
unsigned int index;
int error;
int i;
if (!dev->keycodesize)
return -EINVAL;
if (ke->flags & INPUT_KEYMAP_BY_INDEX) {
index = ke->index;
} else {
error = input_scancode_to_scalar(ke, &index);
if (error)
return error;
}
if (index >= dev->keycodemax)
return -EINVAL;
if (dev->keycodesize < sizeof(ke->keycode) &&
(ke->keycode >> (dev->keycodesize * 8)))
return -EINVAL;
switch (dev->keycodesize) {
case 1: {
u8 *k = (u8 *)dev->keycode;
*old_keycode = k[index];
k[index] = ke->keycode;
break;
}
case 2: {
u16 *k = (u16 *)dev->keycode;
*old_keycode = k[index];
k[index] = ke->keycode;
break;
}
default: {
u32 *k = (u32 *)dev->keycode;
*old_keycode = k[index];
k[index] = ke->keycode;
break;
}
}
__clear_bit(*old_keycode, dev->keybit);
__set_bit(ke->keycode, dev->keybit);
for (i = 0; i < dev->keycodemax; i++) {
if (input_fetch_keycode(dev, i) == *old_keycode) {
__set_bit(*old_keycode, dev->keybit);
break; /* Setting the bit twice is useless, so break */
}
}
return 0;
}
/**
* input_get_keycode - retrieve keycode currently mapped to a given scancode
* @dev: input device which keymap is being queried
* @ke: keymap entry
*
* This function should be called by anyone interested in retrieving current
* keymap. Presently evdev handlers use it.
*/
int input_get_keycode(struct input_dev *dev, struct input_keymap_entry *ke)
{
unsigned long flags;
int retval;
spin_lock_irqsave(&dev->event_lock, flags);
retval = dev->getkeycode(dev, ke);
spin_unlock_irqrestore(&dev->event_lock, flags);
return retval;
}
EXPORT_SYMBOL(input_get_keycode);
/**
* input_set_keycode - attribute a keycode to a given scancode
* @dev: input device which keymap is being updated
* @ke: new keymap entry
*
* This function should be called by anyone needing to update current
* keymap. Presently keyboard and evdev handlers use it.
*/
int input_set_keycode(struct input_dev *dev,
const struct input_keymap_entry *ke)
{
unsigned long flags;
unsigned int old_keycode;
int retval;
if (ke->keycode > KEY_MAX)
return -EINVAL;
spin_lock_irqsave(&dev->event_lock, flags);
retval = dev->setkeycode(dev, ke, &old_keycode);
if (retval)
goto out;
/* Make sure KEY_RESERVED did not get enabled. */
__clear_bit(KEY_RESERVED, dev->keybit);
/*
* Simulate keyup event if keycode is not present
* in the keymap anymore
*/
if (test_bit(EV_KEY, dev->evbit) &&
!is_event_supported(old_keycode, dev->keybit, KEY_MAX) &&
__test_and_clear_bit(old_keycode, dev->key)) {
struct input_value vals[] = {
{ EV_KEY, old_keycode, 0 },
input_value_sync
};
input_pass_values(dev, vals, ARRAY_SIZE(vals));
}
out:
spin_unlock_irqrestore(&dev->event_lock, flags);
return retval;
}
EXPORT_SYMBOL(input_set_keycode);
static const struct input_device_id *input_match_device(struct input_handler *handler,
struct input_dev *dev)
{
const struct input_device_id *id;
for (id = handler->id_table; id->flags || id->driver_info; id++) {
if (id->flags & INPUT_DEVICE_ID_MATCH_BUS)
if (id->bustype != dev->id.bustype)
continue;
if (id->flags & INPUT_DEVICE_ID_MATCH_VENDOR)
if (id->vendor != dev->id.vendor)
continue;
if (id->flags & INPUT_DEVICE_ID_MATCH_PRODUCT)
if (id->product != dev->id.product)
continue;
if (id->flags & INPUT_DEVICE_ID_MATCH_VERSION)
if (id->version != dev->id.version)
continue;
if (!bitmap_subset(id->evbit, dev->evbit, EV_MAX))
continue;
if (!bitmap_subset(id->keybit, dev->keybit, KEY_MAX))
continue;
if (!bitmap_subset(id->relbit, dev->relbit, REL_MAX))
continue;
if (!bitmap_subset(id->absbit, dev->absbit, ABS_MAX))
continue;
if (!bitmap_subset(id->mscbit, dev->mscbit, MSC_MAX))
continue;
if (!bitmap_subset(id->ledbit, dev->ledbit, LED_MAX))
continue;
if (!bitmap_subset(id->sndbit, dev->sndbit, SND_MAX))
continue;
if (!bitmap_subset(id->ffbit, dev->ffbit, FF_MAX))
continue;
if (!bitmap_subset(id->swbit, dev->swbit, SW_MAX))
continue;
if (!handler->match || handler->match(handler, dev))
return id;
}
return NULL;
}
static int input_attach_handler(struct input_dev *dev, struct input_handler *handler)
{
const struct input_device_id *id;
int error;
id = input_match_device(handler, dev);
if (!id)
return -ENODEV;
error = handler->connect(handler, dev, id);
if (error && error != -ENODEV)
pr_err("failed to attach handler %s to device %s, error: %d\n",
handler->name, kobject_name(&dev->dev.kobj), error);
return error;
}
#ifdef CONFIG_COMPAT
static int input_bits_to_string(char *buf, int buf_size,
unsigned long bits, bool skip_empty)
{
int len = 0;
if (INPUT_COMPAT_TEST) {
u32 dword = bits >> 32;
if (dword || !skip_empty)
len += snprintf(buf, buf_size, "%x ", dword);
dword = bits & 0xffffffffUL;
if (dword || !skip_empty || len)
len += snprintf(buf + len, max(buf_size - len, 0),
"%x", dword);
} else {
if (bits || !skip_empty)
len += snprintf(buf, buf_size, "%lx", bits);
}
return len;
}
#else /* !CONFIG_COMPAT */
static int input_bits_to_string(char *buf, int buf_size,
unsigned long bits, bool skip_empty)
{
return bits || !skip_empty ?
snprintf(buf, buf_size, "%lx", bits) : 0;
}
#endif
#ifdef CONFIG_PROC_FS
static struct proc_dir_entry *proc_bus_input_dir;
static DECLARE_WAIT_QUEUE_HEAD(input_devices_poll_wait);
static int input_devices_state;
static inline void input_wakeup_procfs_readers(void)
{
input_devices_state++;
wake_up(&input_devices_poll_wait);
}
static unsigned int input_proc_devices_poll(struct file *file, poll_table *wait)
{
poll_wait(file, &input_devices_poll_wait, wait);
if (file->f_version != input_devices_state) {
file->f_version = input_devices_state;
return POLLIN | POLLRDNORM;
}
return 0;
}
union input_seq_state {
struct {
unsigned short pos;
bool mutex_acquired;
};
void *p;
};
static void *input_devices_seq_start(struct seq_file *seq, loff_t *pos)
{
union input_seq_state *state = (union input_seq_state *)&seq->private;
int error;
/* We need to fit into seq->private pointer */
BUILD_BUG_ON(sizeof(union input_seq_state) != sizeof(seq->private));
error = mutex_lock_interruptible(&input_mutex);
if (error) {
state->mutex_acquired = false;
return ERR_PTR(error);
}
state->mutex_acquired = true;
return seq_list_start(&input_dev_list, *pos);
}
static void *input_devices_seq_next(struct seq_file *seq, void *v, loff_t *pos)
{
return seq_list_next(v, &input_dev_list, pos);
}
static void input_seq_stop(struct seq_file *seq, void *v)
{
union input_seq_state *state = (union input_seq_state *)&seq->private;
if (state->mutex_acquired)
mutex_unlock(&input_mutex);
}
static void input_seq_print_bitmap(struct seq_file *seq, const char *name,
unsigned long *bitmap, int max)
{
int i;
bool skip_empty = true;
char buf[18];
seq_printf(seq, "B: %s=", name);
for (i = BITS_TO_LONGS(max) - 1; i >= 0; i--) {
if (input_bits_to_string(buf, sizeof(buf),
bitmap[i], skip_empty)) {
skip_empty = false;
seq_printf(seq, "%s%s", buf, i > 0 ? " " : "");
}
}
/*
* If no output was produced print a single 0.
*/
if (skip_empty)
seq_puts(seq, "0");
seq_putc(seq, '\n');
}
static int input_devices_seq_show(struct seq_file *seq, void *v)
{
struct input_dev *dev = container_of(v, struct input_dev, node);
const char *path = kobject_get_path(&dev->dev.kobj, GFP_KERNEL);
struct input_handle *handle;
seq_printf(seq, "I: Bus=%04x Vendor=%04x Product=%04x Version=%04x\n",
dev->id.bustype, dev->id.vendor, dev->id.product, dev->id.version);
seq_printf(seq, "N: Name=\"%s\"\n", dev->name ? dev->name : "");
seq_printf(seq, "P: Phys=%s\n", dev->phys ? dev->phys : "");
seq_printf(seq, "S: Sysfs=%s\n", path ? path : "");
seq_printf(seq, "U: Uniq=%s\n", dev->uniq ? dev->uniq : "");
seq_printf(seq, "H: Handlers=");
list_for_each_entry(handle, &dev->h_list, d_node)
seq_printf(seq, "%s ", handle->name);
seq_putc(seq, '\n');
input_seq_print_bitmap(seq, "PROP", dev->propbit, INPUT_PROP_MAX);
input_seq_print_bitmap(seq, "EV", dev->evbit, EV_MAX);
if (test_bit(EV_KEY, dev->evbit))
input_seq_print_bitmap(seq, "KEY", dev->keybit, KEY_MAX);
if (test_bit(EV_REL, dev->evbit))
input_seq_print_bitmap(seq, "REL", dev->relbit, REL_MAX);
if (test_bit(EV_ABS, dev->evbit))
input_seq_print_bitmap(seq, "ABS", dev->absbit, ABS_MAX);
if (test_bit(EV_MSC, dev->evbit))
input_seq_print_bitmap(seq, "MSC", dev->mscbit, MSC_MAX);
if (test_bit(EV_LED, dev->evbit))
input_seq_print_bitmap(seq, "LED", dev->ledbit, LED_MAX);
if (test_bit(EV_SND, dev->evbit))
input_seq_print_bitmap(seq, "SND", dev->sndbit, SND_MAX);
if (test_bit(EV_FF, dev->evbit))
input_seq_print_bitmap(seq, "FF", dev->ffbit, FF_MAX);
if (test_bit(EV_SW, dev->evbit))
input_seq_print_bitmap(seq, "SW", dev->swbit, SW_MAX);
seq_putc(seq, '\n');
kfree(path);
return 0;
}
static const struct seq_operations input_devices_seq_ops = {
.start = input_devices_seq_start,
.next = input_devices_seq_next,
.stop = input_seq_stop,
.show = input_devices_seq_show,
};
static int input_proc_devices_open(struct inode *inode, struct file *file)
{
return seq_open(file, &input_devices_seq_ops);
}
static const struct file_operations input_devices_fileops = {
.owner = THIS_MODULE,
.open = input_proc_devices_open,
.poll = input_proc_devices_poll,
.read = seq_read,
.llseek = seq_lseek,
.release = seq_release,
};
static void *input_handlers_seq_start(struct seq_file *seq, loff_t *pos)
{
union input_seq_state *state = (union input_seq_state *)&seq->private;
int error;
/* We need to fit into seq->private pointer */
BUILD_BUG_ON(sizeof(union input_seq_state) != sizeof(seq->private));
error = mutex_lock_interruptible(&input_mutex);
if (error) {
state->mutex_acquired = false;
return ERR_PTR(error);
}
state->mutex_acquired = true;
state->pos = *pos;
return seq_list_start(&input_handler_list, *pos);
}
static void *input_handlers_seq_next(struct seq_file *seq, void *v, loff_t *pos)
{
union input_seq_state *state = (union input_seq_state *)&seq->private;
state->pos = *pos + 1;
return seq_list_next(v, &input_handler_list, pos);
}
static int input_handlers_seq_show(struct seq_file *seq, void *v)
{
struct input_handler *handler = container_of(v, struct input_handler, node);
union input_seq_state *state = (union input_seq_state *)&seq->private;
seq_printf(seq, "N: Number=%u Name=%s", state->pos, handler->name);
if (handler->filter)
seq_puts(seq, " (filter)");
if (handler->legacy_minors)
seq_printf(seq, " Minor=%d", handler->minor);
seq_putc(seq, '\n');
return 0;
}
static const struct seq_operations input_handlers_seq_ops = {
.start = input_handlers_seq_start,
.next = input_handlers_seq_next,
.stop = input_seq_stop,
.show = input_handlers_seq_show,
};
static int input_proc_handlers_open(struct inode *inode, struct file *file)
{
return seq_open(file, &input_handlers_seq_ops);
}
static const struct file_operations input_handlers_fileops = {
.owner = THIS_MODULE,
.open = input_proc_handlers_open,
.read = seq_read,
.llseek = seq_lseek,
.release = seq_release,
};
static int __init input_proc_init(void)
{
struct proc_dir_entry *entry;
proc_bus_input_dir = proc_mkdir("bus/input", NULL); // 创建文件夹"/proc/bus/input"
if (!proc_bus_input_dir)
return -ENOMEM;
entry = proc_create("devices", 0, proc_bus_input_dir,// 创建节点"/proc/bus/input/devices"
&input_devices_fileops);
if (!entry)
goto fail1;
entry = proc_create("handlers", 0, proc_bus_input_dir,// 创建节点"/proc/bus/input/handlers"
&input_handlers_fileops);
if (!entry)
goto fail2;
return 0;
fail2: remove_proc_entry("devices", proc_bus_input_dir);
fail1: remove_proc_entry("bus/input", NULL);
return -ENOMEM;
}
static void input_proc_exit(void)
{
remove_proc_entry("devices", proc_bus_input_dir);
remove_proc_entry("handlers", proc_bus_input_dir);
remove_proc_entry("bus/input", NULL);
}
#else /* !CONFIG_PROC_FS */
static inline void input_wakeup_procfs_readers(void) { }
static inline int input_proc_init(void) { return 0; }
static inline void input_proc_exit(void) { }
#endif
#define INPUT_DEV_STRING_ATTR_SHOW(name) \
static ssize_t input_dev_show_##name(struct device *dev, \
struct device_attribute *attr, \
char *buf) \
{ \
struct input_dev *input_dev = to_input_dev(dev); \
\
return scnprintf(buf, PAGE_SIZE, "%s\n", \
input_dev->name ? input_dev->name : ""); \
} \
static DEVICE_ATTR(name, S_IRUGO, input_dev_show_##name, NULL)
INPUT_DEV_STRING_ATTR_SHOW(name);
INPUT_DEV_STRING_ATTR_SHOW(phys);
INPUT_DEV_STRING_ATTR_SHOW(uniq);
static int input_print_modalias_bits(char *buf, int size,
char name, unsigned long *bm,
unsigned int min_bit, unsigned int max_bit)
{
int len = 0, i;
len += snprintf(buf, max(size, 0), "%c", name);
for (i = min_bit; i < max_bit; i++)
if (bm[BIT_WORD(i)] & BIT_MASK(i))
len += snprintf(buf + len, max(size - len, 0), "%X,", i);
return len;
}
static int input_print_modalias(char *buf, int size, struct input_dev *id,
int add_cr)
{
int len;
len = snprintf(buf, max(size, 0),
"input:b%04Xv%04Xp%04Xe%04X-",
id->id.bustype, id->id.vendor,
id->id.product, id->id.version);
len += input_print_modalias_bits(buf + len, size - len,
'e', id->evbit, 0, EV_MAX);
len += input_print_modalias_bits(buf + len, size - len,
'k', id->keybit, KEY_MIN_INTERESTING, KEY_MAX);
len += input_print_modalias_bits(buf + len, size - len,
'r', id->relbit, 0, REL_MAX);
len += input_print_modalias_bits(buf + len, size - len,
'a', id->absbit, 0, ABS_MAX);
len += input_print_modalias_bits(buf + len, size - len,
'm', id->mscbit, 0, MSC_MAX);
len += input_print_modalias_bits(buf + len, size - len,
'l', id->ledbit, 0, LED_MAX);
len += input_print_modalias_bits(buf + len, size - len,
's', id->sndbit, 0, SND_MAX);
len += input_print_modalias_bits(buf + len, size - len,
'f', id->ffbit, 0, FF_MAX);
len += input_print_modalias_bits(buf + len, size - len,
'w', id->swbit, 0, SW_MAX);
if (add_cr)
len += snprintf(buf + len, max(size - len, 0), "\n");
return len;
}
static ssize_t input_dev_show_modalias(struct device *dev,
struct device_attribute *attr,
char *buf)
{
struct input_dev *id = to_input_dev(dev);
ssize_t len;
len = input_print_modalias(buf, PAGE_SIZE, id, 1);
return min_t(int, len, PAGE_SIZE);
}
static DEVICE_ATTR(modalias, S_IRUGO, input_dev_show_modalias, NULL);
static int input_print_bitmap(char *buf, int buf_size, unsigned long *bitmap,
int max, int add_cr);
static ssize_t input_dev_show_properties(struct device *dev,
struct device_attribute *attr,
char *buf)
{
struct input_dev *input_dev = to_input_dev(dev);
int len = input_print_bitmap(buf, PAGE_SIZE, input_dev->propbit,
INPUT_PROP_MAX, true);
return min_t(int, len, PAGE_SIZE);
}
static DEVICE_ATTR(properties, S_IRUGO, input_dev_show_properties, NULL);
static struct attribute *input_dev_attrs[] = {
&dev_attr_name.attr,
&dev_attr_phys.attr,
&dev_attr_uniq.attr,
&dev_attr_modalias.attr,
&dev_attr_properties.attr,
NULL
};
static struct attribute_group input_dev_attr_group = {
.attrs = input_dev_attrs,
};
#define INPUT_DEV_ID_ATTR(name) \
static ssize_t input_dev_show_id_##name(struct device *dev, \
struct device_attribute *attr, \
char *buf) \
{ \
struct input_dev *input_dev = to_input_dev(dev); \
return scnprintf(buf, PAGE_SIZE, "%04x\n", input_dev->id.name); \
} \
static DEVICE_ATTR(name, S_IRUGO, input_dev_show_id_##name, NULL)
INPUT_DEV_ID_ATTR(bustype);
INPUT_DEV_ID_ATTR(vendor);
INPUT_DEV_ID_ATTR(product);
INPUT_DEV_ID_ATTR(version);
static struct attribute *input_dev_id_attrs[] = {
&dev_attr_bustype.attr,
&dev_attr_vendor.attr,
&dev_attr_product.attr,
&dev_attr_version.attr,
NULL
};
static struct attribute_group input_dev_id_attr_group = {
.name = "id",
.attrs = input_dev_id_attrs,
};
static int input_print_bitmap(char *buf, int buf_size, unsigned long *bitmap,
int max, int add_cr)
{
int i;
int len = 0;
bool skip_empty = true;
for (i = BITS_TO_LONGS(max) - 1; i >= 0; i--) {
len += input_bits_to_string(buf + len, max(buf_size - len, 0),
bitmap[i], skip_empty);
if (len) {
skip_empty = false;
if (i > 0)
len += snprintf(buf + len, max(buf_size - len, 0), " ");
}
}
/*
* If no output was produced print a single 0.
*/
if (len == 0)
len = snprintf(buf, buf_size, "%d", 0);
if (add_cr)
len += snprintf(buf + len, max(buf_size - len, 0), "\n");
return len;
}
#define INPUT_DEV_CAP_ATTR(ev, bm) \
static ssize_t input_dev_show_cap_##bm(struct device *dev, \
struct device_attribute *attr, \
char *buf) \
{ \
struct input_dev *input_dev = to_input_dev(dev); \
int len = input_print_bitmap(buf, PAGE_SIZE, \
input_dev->bm##bit, ev##_MAX, \
true); \
return min_t(int, len, PAGE_SIZE); \
} \
static DEVICE_ATTR(bm, S_IRUGO, input_dev_show_cap_##bm, NULL)
INPUT_DEV_CAP_ATTR(EV, ev);
INPUT_DEV_CAP_ATTR(KEY, key);
INPUT_DEV_CAP_ATTR(REL, rel);
INPUT_DEV_CAP_ATTR(ABS, abs);
INPUT_DEV_CAP_ATTR(MSC, msc);
INPUT_DEV_CAP_ATTR(LED, led);
INPUT_DEV_CAP_ATTR(SND, snd);
INPUT_DEV_CAP_ATTR(FF, ff);
INPUT_DEV_CAP_ATTR(SW, sw);
static struct attribute *input_dev_caps_attrs[] = {
&dev_attr_ev.attr,
&dev_attr_key.attr,
&dev_attr_rel.attr,
&dev_attr_abs.attr,
&dev_attr_msc.attr,
&dev_attr_led.attr,
&dev_attr_snd.attr,
&dev_attr_ff.attr,
&dev_attr_sw.attr,
NULL
};
static struct attribute_group input_dev_caps_attr_group = {
.name = "capabilities",
.attrs = input_dev_caps_attrs,
};
static const struct attribute_group *input_dev_attr_groups[] = {
&input_dev_attr_group,
&input_dev_id_attr_group,
&input_dev_caps_attr_group,
NULL
};
static void input_dev_release(struct device *device)
{
struct input_dev *dev = to_input_dev(device);
input_ff_destroy(dev);
input_mt_destroy_slots(dev);
kfree(dev->absinfo);
kfree(dev->vals);
kfree(dev);
module_put(THIS_MODULE);
}
/*
* Input uevent interface - loading event handlers based on
* device bitfields.
*/
static int input_add_uevent_bm_var(struct kobj_uevent_env *env,
const char *name, unsigned long *bitmap, int max)
{
int len;
if (add_uevent_var(env, "%s", name))
return -ENOMEM;
len = input_print_bitmap(&env->buf[env->buflen - 1],
sizeof(env->buf) - env->buflen,
bitmap, max, false);
if (len >= (sizeof(env->buf) - env->buflen))
return -ENOMEM;
env->buflen += len;
return 0;
}
static int input_add_uevent_modalias_var(struct kobj_uevent_env *env,
struct input_dev *dev)
{
int len;
if (add_uevent_var(env, "MODALIAS="))
return -ENOMEM;
len = input_print_modalias(&env->buf[env->buflen - 1],
sizeof(env->buf) - env->buflen,
dev, 0);
if (len >= (sizeof(env->buf) - env->buflen))
return -ENOMEM;
env->buflen += len;
return 0;
}
#define INPUT_ADD_HOTPLUG_VAR(fmt, val...) \
do { \
int err = add_uevent_var(env, fmt, val); \
if (err) \
return err; \
} while (0)
#define INPUT_ADD_HOTPLUG_BM_VAR(name, bm, max) \
do { \
int err = input_add_uevent_bm_var(env, name, bm, max); \
if (err) \
return err; \
} while (0)
#define INPUT_ADD_HOTPLUG_MODALIAS_VAR(dev) \
do { \
int err = input_add_uevent_modalias_var(env, dev); \
if (err) \
return err; \
} while (0)
static int input_dev_uevent(struct device *device, struct kobj_uevent_env *env)
{
struct input_dev *dev = to_input_dev(device);
INPUT_ADD_HOTPLUG_VAR("PRODUCT=%x/%x/%x/%x",
dev->id.bustype, dev->id.vendor,
dev->id.product, dev->id.version);
if (dev->name)
INPUT_ADD_HOTPLUG_VAR("NAME=\"%s\"", dev->name);
if (dev->phys)
INPUT_ADD_HOTPLUG_VAR("PHYS=\"%s\"", dev->phys);
if (dev->uniq)
INPUT_ADD_HOTPLUG_VAR("UNIQ=\"%s\"", dev->uniq);
INPUT_ADD_HOTPLUG_BM_VAR("PROP=", dev->propbit, INPUT_PROP_MAX);
INPUT_ADD_HOTPLUG_BM_VAR("EV=", dev->evbit, EV_MAX);
if (test_bit(EV_KEY, dev->evbit))
INPUT_ADD_HOTPLUG_BM_VAR("KEY=", dev->keybit, KEY_MAX);
if (test_bit(EV_REL, dev->evbit))
INPUT_ADD_HOTPLUG_BM_VAR("REL=", dev->relbit, REL_MAX);
if (test_bit(EV_ABS, dev->evbit))
INPUT_ADD_HOTPLUG_BM_VAR("ABS=", dev->absbit, ABS_MAX);
if (test_bit(EV_MSC, dev->evbit))
INPUT_ADD_HOTPLUG_BM_VAR("MSC=", dev->mscbit, MSC_MAX);
if (test_bit(EV_LED, dev->evbit))
INPUT_ADD_HOTPLUG_BM_VAR("LED=", dev->ledbit, LED_MAX);
if (test_bit(EV_SND, dev->evbit))
INPUT_ADD_HOTPLUG_BM_VAR("SND=", dev->sndbit, SND_MAX);
if (test_bit(EV_FF, dev->evbit))
INPUT_ADD_HOTPLUG_BM_VAR("FF=", dev->ffbit, FF_MAX);
if (test_bit(EV_SW, dev->evbit))
INPUT_ADD_HOTPLUG_BM_VAR("SW=", dev->swbit, SW_MAX);
INPUT_ADD_HOTPLUG_MODALIAS_VAR(dev);
return 0;
}
#define INPUT_DO_TOGGLE(dev, type, bits, on) \
do { \
int i; \
bool active; \
\
if (!test_bit(EV_##type, dev->evbit)) \
break; \
\
for (i = 0; i < type##_MAX; i++) { \
if (!test_bit(i, dev->bits##bit)) \
continue; \
\
active = test_bit(i, dev->bits); \
if (!active && !on) \
continue; \
\
dev->event(dev, EV_##type, i, on ? active : 0); \
} \
} while (0)
static void input_dev_toggle(struct input_dev *dev, bool activate)
{
if (!dev->event)
return;
INPUT_DO_TOGGLE(dev, LED, led, activate);
INPUT_DO_TOGGLE(dev, SND, snd, activate);
if (activate && test_bit(EV_REP, dev->evbit)) {
dev->event(dev, EV_REP, REP_PERIOD, dev->rep[REP_PERIOD]);
dev->event(dev, EV_REP, REP_DELAY, dev->rep[REP_DELAY]);
}
}
/**
* input_reset_device() - reset/restore the state of input device
* @dev: input device whose state needs to be reset
*
* This function tries to reset the state of an opened input device and
* bring internal state and state if the hardware in sync with each other.
* We mark all keys as released, restore LED state, repeat rate, etc.
*/
void input_reset_device(struct input_dev *dev)
{
unsigned long flags;
mutex_lock(&dev->mutex);
spin_lock_irqsave(&dev->event_lock, flags);
input_dev_toggle(dev, true);
input_dev_release_keys(dev);
spin_unlock_irqrestore(&dev->event_lock, flags);
mutex_unlock(&dev->mutex);
}
EXPORT_SYMBOL(input_reset_device);
#ifdef CONFIG_PM_SLEEP
static int input_dev_suspend(struct device *dev)
{
struct input_dev *input_dev = to_input_dev(dev);
spin_lock_irq(&input_dev->event_lock);
/*
* Keys that are pressed now are unlikely to be
* still pressed when we resume.
*/
input_dev_release_keys(input_dev);
/* Turn off LEDs and sounds, if any are active. */
input_dev_toggle(input_dev, false);
spin_unlock_irq(&input_dev->event_lock);
return 0;
}
static int input_dev_resume(struct device *dev)
{
struct input_dev *input_dev = to_input_dev(dev);
spin_lock_irq(&input_dev->event_lock);
/* Restore state of LEDs and sounds, if any were active. */
input_dev_toggle(input_dev, true);
spin_unlock_irq(&input_dev->event_lock);
return 0;
}
static int input_dev_freeze(struct device *dev)
{
struct input_dev *input_dev = to_input_dev(dev);
spin_lock_irq(&input_dev->event_lock);
/*
* Keys that are pressed now are unlikely to be
* still pressed when we resume.
*/
input_dev_release_keys(input_dev);
spin_unlock_irq(&input_dev->event_lock);
return 0;
}
static int input_dev_poweroff(struct device *dev)
{
struct input_dev *input_dev = to_input_dev(dev);
spin_lock_irq(&input_dev->event_lock);
/* Turn off LEDs and sounds, if any are active. */
input_dev_toggle(input_dev, false);
spin_unlock_irq(&input_dev->event_lock);
return 0;
}
static const struct dev_pm_ops input_dev_pm_ops = {
.suspend = input_dev_suspend,
.resume = input_dev_resume,
.freeze = input_dev_freeze,
.poweroff = input_dev_poweroff,
.restore = input_dev_resume,
};
#endif /* CONFIG_PM */
static struct device_type input_dev_type = {
.groups = input_dev_attr_groups,
.release = input_dev_release,
.uevent = input_dev_uevent,
#ifdef CONFIG_PM_SLEEP
.pm = &input_dev_pm_ops,
#endif
};
static char *input_devnode(struct device *dev, umode_t *mode)
{
return kasprintf(GFP_KERNEL, "input/%s", dev_name(dev));
}
struct class input_class = {
.name = "input",
.devnode = input_devnode,
};
EXPORT_SYMBOL_GPL(input_class);
struct input_devres {
struct input_dev *input;
};
static int devm_input_device_match(struct device *dev, void *res, void *data)
{
struct input_devres *devres = res;
return devres->input == data;
}
static void devm_input_device_release(struct device *dev, void *res)
{
struct input_devres *devres = res;
struct input_dev *input = devres->input;
dev_dbg(dev, "%s: dropping reference to %s\n",
__func__, dev_name(&input->dev));
input_put_device(input);
}
/**
* devm_input_allocate_device - allocate managed input device
* @dev: device owning the input device being created
*
* Returns prepared struct input_dev or %NULL.
*
* Managed input devices do not need to be explicitly unregistered or
* freed as it will be done automatically when owner device unbinds from
* its driver (or binding fails). Once managed input device is allocated,
* it is ready to be set up and registered in the same fashion as regular
* input device. There are no special devm_input_device_[un]register()
* variants, regular ones work with both managed and unmanaged devices,
* should you need them. In most cases however, managed input device need
* not be explicitly unregistered or freed.
*
* NOTE: the owner device is set up as parent of input device and users
* should not override it.
*/
struct input_dev *devm_input_allocate_device(struct device *dev)
{
struct input_dev *input;
struct input_devres *devres;
devres = devres_alloc(devm_input_device_release,
sizeof(struct input_devres), GFP_KERNEL);
if (!devres)
return NULL;
input = input_allocate_device();
if (!input) {
devres_free(devres);
return NULL;
}
input->dev.parent = dev;
input->devres_managed = true;
devres->input = input;
devres_add(dev, devres);
return input;
}
EXPORT_SYMBOL(devm_input_allocate_device);
/**
* input_free_device - free memory occupied by input_dev structure
* @dev: input device to free
*
* This function should only be used if input_register_device()
* was not called yet or if it failed. Once device was registered
* use input_unregister_device() and memory will be freed once last
* reference to the device is dropped.
*
* Device should be allocated by input_allocate_device().
*
* NOTE: If there are references to the input device then memory
* will not be freed until last reference is dropped.
*/
void input_free_device(struct input_dev *dev)
{
if (dev) {
if (dev->devres_managed)
WARN_ON(devres_destroy(dev->dev.parent,
devm_input_device_release,
devm_input_device_match,
dev));
input_put_device(dev);
}
}
EXPORT_SYMBOL(input_free_device);
/**
* input_set_capability - mark device as capable of a certain event
* @dev: device that is capable of emitting or accepting event
* @type: type of the event (EV_KEY, EV_REL, etc...)
* @code: event code
*
* In addition to setting up corresponding bit in appropriate capability
* bitmap the function also adjusts dev->evbit.
*/
void input_set_capability(struct input_dev *dev, unsigned int type, unsigned int code)
{
switch (type) {
case EV_KEY:
__set_bit(code, dev->keybit);
break;
case EV_REL:
__set_bit(code, dev->relbit);
break;
case EV_ABS:
input_alloc_absinfo(dev);
if (!dev->absinfo)
return;
__set_bit(code, dev->absbit);
break;
case EV_MSC:
__set_bit(code, dev->mscbit);
break;
case EV_SW:
__set_bit(code, dev->swbit);
break;
case EV_LED:
__set_bit(code, dev->ledbit);
break;
case EV_SND:
__set_bit(code, dev->sndbit);
break;
case EV_FF:
__set_bit(code, dev->ffbit);
break;
case EV_PWR:
/* do nothing */
break;
default:
pr_err("input_set_capability: unknown type %u (code %u)\n",
type, code);
dump_stack();
return;
}
__set_bit(type, dev->evbit);
}
EXPORT_SYMBOL(input_set_capability);
static unsigned int input_estimate_events_per_packet(struct input_dev *dev)
{
int mt_slots;
int i;
unsigned int events;
if (dev->mt) {
mt_slots = dev->mt->num_slots;
} else if (test_bit(ABS_MT_TRACKING_ID, dev->absbit)) {
mt_slots = dev->absinfo[ABS_MT_TRACKING_ID].maximum -
dev->absinfo[ABS_MT_TRACKING_ID].minimum + 1,
mt_slots = clamp(mt_slots, 2, 32);
} else if (test_bit(ABS_MT_POSITION_X, dev->absbit)) {
mt_slots = 2;
} else {
mt_slots = 0;
}
events = mt_slots + 1; /* count SYN_MT_REPORT and SYN_REPORT */
for (i = 0; i < ABS_CNT; i++) {
if (test_bit(i, dev->absbit)) {
if (input_is_mt_axis(i))
events += mt_slots;
else
events++;
}
}
for (i = 0; i < REL_CNT; i++)
if (test_bit(i, dev->relbit))
events++;
/* Make room for KEY and MSC events */
events += 7;
return events;
}
#define INPUT_CLEANSE_BITMASK(dev, type, bits) \
do { \
if (!test_bit(EV_##type, dev->evbit)) \
memset(dev->bits##bit, 0, \
sizeof(dev->bits##bit)); \
} while (0)
static void input_cleanse_bitmasks(struct input_dev *dev)
{
INPUT_CLEANSE_BITMASK(dev, KEY, key);
INPUT_CLEANSE_BITMASK(dev, REL, rel);
INPUT_CLEANSE_BITMASK(dev, ABS, abs);
INPUT_CLEANSE_BITMASK(dev, MSC, msc);
INPUT_CLEANSE_BITMASK(dev, LED, led);
INPUT_CLEANSE_BITMASK(dev, SND, snd);
INPUT_CLEANSE_BITMASK(dev, FF, ff);
INPUT_CLEANSE_BITMASK(dev, SW, sw);
}
static void __input_unregister_device(struct input_dev *dev)
{
struct input_handle *handle, *next;
input_disconnect_device(dev);
mutex_lock(&input_mutex);
list_for_each_entry_safe(handle, next, &dev->h_list, d_node)
handle->handler->disconnect(handle);
WARN_ON(!list_empty(&dev->h_list));
del_timer_sync(&dev->timer);
list_del_init(&dev->node);
input_wakeup_procfs_readers();
mutex_unlock(&input_mutex);
device_del(&dev->dev);
}
static void devm_input_device_unregister(struct device *dev, void *res)
{
struct input_devres *devres = res;
struct input_dev *input = devres->input;
dev_dbg(dev, "%s: unregistering device %s\n",
__func__, dev_name(&input->dev));
__input_unregister_device(input);
}
struct input_dev *input_allocate_device(void)
{
static atomic_t input_no = ATOMIC_INIT(0);
struct input_dev *dev;
dev = kzalloc(sizeof(struct input_dev), GFP_KERNEL);// 注意GFP_KERNEL可能导致睡眠，不能在中断中调用这个函数
if (dev) {
dev->dev.type = &input_dev_type;
dev->dev.class = &input_class; //支持热插拔的结构体
device_initialize(&dev->dev);
mutex_init(&dev->mutex);
spin_lock_init(&dev->event_lock);
init_timer(&dev->timer);
INIT_LIST_HEAD(&dev->h_list);
INIT_LIST_HEAD(&dev->node);
dev_set_name(&dev->dev, "input%lu", // ???
(unsigned long) atomic_inc_return(&input_no) - 1);
__module_get(THIS_MODULE);
}
return dev;
}
EXPORT_SYMBOL(input_allocate_device);
int input_register_device(struct input_dev *dev)
{
struct input_devres *devres = NULL;
struct input_handler *handler;
unsigned int packet_size;
const char *path;
int error;
if (dev->devres_managed) {
devres = devres_alloc(devm_input_device_unregister,
sizeof(struct input_devres), GFP_KERNEL);
if (!devres)
return -ENOMEM;
devres->input = dev;
}
__set_bit(EV_SYN, dev->evbit); // 默认所有的输入设备都支持EV_SYN同步事件
/* KEY_RESERVED is not supposed to be transmitted to userspace. */
__clear_bit(KEY_RESERVED, dev->keybit);
/* Make sure that bitmasks not mentioned in dev->evbit are clean. */
input_cleanse_bitmasks(dev);
packet_size = input_estimate_events_per_packet(dev);
if (dev->hint_events_per_packet < packet_size)
dev->hint_events_per_packet = packet_size;
dev->max_vals = dev->hint_events_per_packet + 2;
dev->vals = kcalloc(dev->max_vals, sizeof(*dev->vals), GFP_KERNEL);
if (!dev->vals) {
error = -ENOMEM;
goto err_devres_free;
}
/*
如果设备驱动没有指定重复按键（连击），系统默认提供以下的支持
init_timer为连击产生的定时器，时间到调用input_repeat_key函数上报
REP_DELAY - 设置重复按键的键值
REP_PERIOD - 设置延时时间
*/
if (!dev->rep[REP_DELAY] && !dev->rep[REP_PERIOD]) {
dev->timer.data = (long) dev;
dev->timer.function = input_repeat_key;
dev->rep[REP_DELAY] = 250;
dev->rep[REP_PERIOD] = 33;
}
// 如果设备驱动没有设置自己的获取键值的函数，系统默认
if (!dev->getkeycode)
dev->getkeycode = input_default_getkeycode;
// 如果设备驱动没有指定按键重置函数，系统默认
if (!dev->setkeycode)
dev->setkeycode = input_default_setkeycode;
// 在/sys目录下创建设备目录和文件
error = device_add(&dev->dev);
if (error)
goto err_free_vals;
// 获取并打印设备的绝对路径名称
path = kobject_get_path(&dev->dev.kobj, GFP_KERNEL);
pr_info("%s as %s\n",
dev->name ? dev->name : "Unspecified device",
path ? path : "N/A");
kfree(path);
error = mutex_lock_interruptible(&input_mutex);
if (error)
goto err_device_del;
list_add_tail(&dev->node, &input_dev_list); // 重要，把设备挂到全局的input子设备链表input_dev_list上
/*
核心重点
遍历input_handler_list链表，链表中每一个handler(事件处理器)均尝试与dev(input子设备)匹配
匹配包括: 总线类型、供应商、生产id、版本id、驱动中配置的事件类型(abs、rel等)
匹配成功后返回id
注: input_register_handler() 与 input_register_device() 都会遍历链表 匹配
*/
list_for_each_entry(handler, &input_handler_list, node)
input_attach_handler(dev, handler);
input_wakeup_procfs_readers();
mutex_unlock(&input_mutex);
if (dev->devres_managed) {
dev_dbg(dev->dev.parent, "%s: registering %s with devres.\n",
__func__, dev_name(&dev->dev));
devres_add(dev->dev.parent, devres);
}
return 0;
err_device_del:
device_del(&dev->dev);
err_free_vals:
kfree(dev->vals);
dev->vals = NULL;
err_devres_free:
devres_free(devres);
return error;
}
EXPORT_SYMBOL(input_register_device);
static int input_attach_handler(struct input_dev *dev, struct input_handler *handler)
{
const struct input_device_id *id;
int error;
// 匹配成功后，将匹配上的handler(事件处理器)的id返回 -- 即找到最合适的事件处理器(tp用的evdev)
// 匹配handler->id_table[]中有标明的flag包括: 总线类型、供应商、生产id、版本id、驱动中配置的事件类型(abs、rel等)
// evdev 的id_table[] 为空，即和任何dev(input子设备)匹配
id = input_match_device(handler, dev);
if (!id)
return -ENODEV;
// 定义在 kernel-3.18/drivers/input/evdev.c
error = handler->connect(handler, dev, id);
if (error && error != -ENODEV)
pr_err("failed to attach handler %s to device %s, error: %d\n",
handler->name, kobject_name(&dev->dev.kobj), error);
return error;
}
static const struct input_device_id *input_match_device(struct input_handler *handler,
struct input_dev *dev)
{
const struct input_device_id *id;
// 如果handler->id_table中的flags、driver_info被设置，则进行匹配
// evdev 的id_table[] 为空，即和任何dev(input子设备)匹配
for (id = handler->id_table; id->flags || id->driver_info; id++) {
if (id->flags & INPUT_DEVICE_ID_MATCH_BUS)// 如果flag中INPUT_DEVICE_ID_MATCH_BUS位被设置
if (id->bustype != dev->id.bustype) // 匹配总线类型
continue;
if (id->flags & INPUT_DEVICE_ID_MATCH_VENDOR)
if (id->vendor != dev->id.vendor) // 匹配供应商
continue;
if (id->flags & INPUT_DEVICE_ID_MATCH_PRODUCT)
if (id->product != dev->id.product) // 匹配生产id
continue;
if (id->flags & INPUT_DEVICE_ID_MATCH_VERSION)
if (id->version != dev->id.version) // 匹配版本id
continue;
// 如果前面都匹配上了，接着进行匹配我们在驱动中设置的事件类型
if (!bitmap_subset(id->evbit, dev->evbit, EV_MAX))
continue;
if (!bitmap_subset(id->keybit, dev->keybit, KEY_MAX))
continue;
if (!bitmap_subset(id->relbit, dev->relbit, REL_MAX))
continue;
if (!bitmap_subset(id->absbit, dev->absbit, ABS_MAX))
continue;
if (!bitmap_subset(id->mscbit, dev->mscbit, MSC_MAX))
continue;
if (!bitmap_subset(id->ledbit, dev->ledbit, LED_MAX))
continue;
if (!bitmap_subset(id->sndbit, dev->sndbit, SND_MAX))
continue;
if (!bitmap_subset(id->ffbit, dev->ffbit, FF_MAX))
continue;
if (!bitmap_subset(id->swbit, dev->swbit, SW_MAX))
continue;
if (!handler->match || handler->match(handler, dev))
return id; // 上述匹配均符合，则返回id
}
return NULL;
}
/**
* input_unregister_device - unregister previously registered device
* @dev: device to be unregistered
*
* This function unregisters an input device. Once device is unregistered
* the caller should not try to access it as it may get freed at any moment.
*/
void input_unregister_device(struct input_dev *dev)
{
if (dev->devres_managed) {
WARN_ON(devres_destroy(dev->dev.parent,
devm_input_device_unregister,
devm_input_device_match,
dev));
__input_unregister_device(dev);
/*
* We do not do input_put_device() here because it will be done
* when 2nd devres fires up.
*/
} else {
__input_unregister_device(dev);
input_put_device(dev);
}
}
EXPORT_SYMBOL(input_unregister_device);
// kernel-3.18/drivers/input/evdev.c 中 evdev_init() -- module_init()
int input_register_handler(struct input_handler *handler)
{
struct input_dev *dev;
int error;
error = mutex_lock_interruptible(&input_mutex);
if (error)
return error;
INIT_LIST_HEAD(&handler->h_list);
// 重要，把设备挂到全局的事件处理器链表input_handler_list上
list_add_tail(&handler->node, &input_handler_list);
/*
核心重点
遍历input_dev_list链表，链表中每一个dev均尝试与handler(事件处理器)匹配
匹配包括: 总线类型、供应商、生产id、版本id、驱动中配置的事件类型(abs、rel等)
匹配成功后返回id
注: input_register_handler() 与 input_register_device() 都会遍历链表 匹配
*/
list_for_each_entry(dev, &input_dev_list, node)
input_attach_handler(dev, handler);
input_wakeup_procfs_readers();
mutex_unlock(&input_mutex);
return 0;
}
EXPORT_SYMBOL(input_register_handler);
/**
* input_unregister_handler - unregisters an input handler
* @handler: handler to be unregistered
*
* This function disconnects a handler from its input devices and
* removes it from lists of known handlers.
*/
void input_unregister_handler(struct input_handler *handler)
{
struct input_handle *handle, *next;
mutex_lock(&input_mutex);
list_for_each_entry_safe(handle, next, &handler->h_list, h_node)
handler->disconnect(handle);
WARN_ON(!list_empty(&handler->h_list));
list_del_init(&handler->node);
input_wakeup_procfs_readers();
mutex_unlock(&input_mutex);
}
EXPORT_SYMBOL(input_unregister_handler);
/**
* input_handler_for_each_handle - handle iterator
* @handler: input handler to iterate
* @data: data for the callback
* @fn: function to be called for each handle
*
* Iterate over @bus's list of devices, and call @fn for each, passing
* it @data and stop when @fn returns a non-zero value. The function is
* using RCU to traverse the list and therefore may be usind in atonic
* contexts. The @fn callback is invoked from RCU critical section and
* thus must not sleep.
*/
int input_handler_for_each_handle(struct input_handler *handler, void *data,
int (*fn)(struct input_handle *, void *))
{
struct input_handle *handle;
int retval = 0;
rcu_read_lock();
list_for_each_entry_rcu(handle, &handler->h_list, h_node) {
retval = fn(handle, data);
if (retval)
break;
}
rcu_read_unlock();
return retval;
}
EXPORT_SYMBOL(input_handler_for_each_handle);
/**
* input_register_handle - register a new input handle
* @handle: handle to register
*
* This function puts a new input handle onto device's
* and handler's lists so that events can flow through
* it once it is opened using input_open_device().
*
* This function is supposed to be called from handler's
* connect() method.
*/
int input_register_handle(struct input_handle *handle)
{
struct input_handler *handler = handle->handler;
struct input_dev *dev = handle->dev;
int error;
/*
* We take dev->mutex here to prevent race with
* input_release_device().
*/
error = mutex_lock_interruptible(&dev->mutex);
if (error)
return error;
/*
* Filters go to the head of the list, normal handlers
* to the tail.
*/
if (handler->filter)
list_add_rcu(&handle->d_node, &dev->h_list);
else
list_add_tail_rcu(&handle->d_node, &dev->h_list);
mutex_unlock(&dev->mutex);
/*
* Since we are supposed to be called from ->connect()
* which is mutually exclusive with ->disconnect()
* we can't be racing with input_unregister_handle()
* and so separate lock is not needed here.
*/
list_add_tail_rcu(&handle->h_node, &handler->h_list);
if (handler->start)
handler->start(handle);
return 0;
}
EXPORT_SYMBOL(input_register_handle);
/**
* input_unregister_handle - unregister an input handle
* @handle: handle to unregister
*
* This function removes input handle from device's
* and handler's lists.
*
* This function is supposed to be called from handler's
* disconnect() method.
*/
void input_unregister_handle(struct input_handle *handle)
{
struct input_dev *dev = handle->dev;
list_del_rcu(&handle->h_node);
/*
* Take dev->mutex to prevent race with input_release_device().
*/
mutex_lock(&dev->mutex);
list_del_rcu(&handle->d_node);
mutex_unlock(&dev->mutex);
synchronize_rcu();
}
EXPORT_SYMBOL(input_unregister_handle);
/**
* input_get_new_minor - allocates a new input minor number
* @legacy_base: beginning or the legacy range to be searched
* @legacy_num: size of legacy range
* @allow_dynamic: whether we can also take ID from the dynamic range
*
* This function allocates a new device minor for from input major namespace.
* Caller can request legacy minor by specifying @legacy_base and @legacy_num
* parameters and whether ID can be allocated from dynamic range if there are
* no free IDs in legacy range.
*/
int input_get_new_minor(int legacy_base, unsigned int legacy_num,
bool allow_dynamic)
{
/*
* This function should be called from input handler's ->connect()
* methods, which are serialized with input_mutex, so no additional
* locking is needed here.
*/
if (legacy_base >= 0) {
int minor = ida_simple_get(&input_ida,
legacy_base,
legacy_base + legacy_num,
GFP_KERNEL);
if (minor >= 0 || !allow_dynamic)
return minor;
}
return ida_simple_get(&input_ida,
INPUT_FIRST_DYNAMIC_DEV, INPUT_MAX_CHAR_DEVICES,
GFP_KERNEL);
}
EXPORT_SYMBOL(input_get_new_minor);
/**
* input_free_minor - release previously allocated minor
* @minor: minor to be released
*
* This function releases previously allocated input minor so that it can be
* reused later.
*/
void input_free_minor(unsigned int minor)
{
ida_simple_remove(&input_ida, minor);
}
EXPORT_SYMBOL(input_free_minor);
static int __init input_init(void)
{
int err;
// 与class_create()类似，内部都调用__class_register()
// 将class注册到内核中，同时创建/sys/class/下节点
err = class_register(&input_class);
if (err) {
pr_err("unable to register input_dev class\n");
return err;
}
err = input_proc_init();
if (err)
goto fail1;
// 根据要求申请主设备号，主设备号INPUT_MAJOR == 13
err = register_chrdev_region(MKDEV(INPUT_MAJOR, 0),
INPUT_MAX_CHAR_DEVICES, "input");
if (err) {
pr_err("unable to register char major %d", INPUT_MAJOR);
goto fail2;
}
return 0;
fail2: input_proc_exit();
fail1: class_unregister(&input_class);
return err;
}
static void __exit input_exit(void)
{
input_proc_exit();
unregister_chrdev_region(MKDEV(INPUT_MAJOR, 0),
INPUT_MAX_CHAR_DEVICES);
class_unregister(&input_class);
}
subsys_initcall(input_init);
module_exit(input_exit);
/*
input子系统分析:
input.c
向下对驱动层提供的接口有:
inpu
阅读背景：
input子系统分析：源码1. kernel-3.18\drivers\input\input.c
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