之所以要引入子系统,是为了让程序更标准化。之前的按键程序,虽然最后相对比较完善,但是不是通用的,别人在不熟悉的情况下是不能随心所欲调用的。显然这与实际应用不合.input输入子系统是内核源码自带的,如果按他这种框架来写,写出的程序就可以很方便地被上层调用,而不用过份关注一些其他的问题。
首先,分析一个驱动程序,先从入口函数开始。static int __init input_init()中有一句err = register_chrdev(INPUT_MAJOR, "input", &input_fops);是用来注册设备的,接下来再看注册设备的信息。
在
static const struct file_operations input_fops = {
.owner = THIS_MODULE,
.open = input_open_file,
};
想调用open肯定要进入input_open_file中执行,打开input_open_file 分析见代码中的注释。根据实际情况构造新的new_fops.
err = new_fops
->open
(inode
, file
); // 返回新的fops
应用程序中要读就要执行:
read > ... > file->f_op->read
input_table数组由谁构造
MODULE_DEVICE_TABLE(input, evdev_ids); // 源自drivers\input\Evdev.c
static struct input_handler evdev_handler = {
.event = evdev_event, // 事件
.connect = evdev_connect, // 连接
.disconnect = evdev_disconnect, // 断开连接,关联
.fops = &evdev_fops, // fops
.minor = EVDEV_MINOR_BASE, // 次设备号
.name = "evdev", // 设备名
.id_table = evdev_ids, // id_table 表示可以支持的设备 如果id_table支持设备则调用connect函数。让input_device(硬件上的)和input_handler(软件上的)建立一个连接。
};
input_register_handler(软件上的)
注册input_handler:
input_register_handler:
input_table[handler->minor >> 5] = handler // 数组
list_add_tail(&handler->node, &input_handler_list); // 放入链表
list_for_each_entry(dev, &input_dev_list, node) // 对于每一个input_dev调用input_attach_handler
input_attach_handler(dev, handler); // 根据input_handler中的id_table来判断能否支持这个input_dev
注册输入设备
input_register_device
list_add_tail(&dev->node, &input_dev_list) // 放入链表
list_for_each_entry(handler, &input_handler_list, node) // 对input_handler_list中的每一个条目都调用input_attach_handler();
input_attach_handler(dev, handler); // 根据input_handler中的id_table来判断能否支持这个input_dev
input_attach_handler:
id = input_match_device(handler->id_table, dev);
error = handler->connect(handler, dev, id);
根据注册input_dev或input_handler时,会两两比较input_dev和input_handler
根据input_handler的id_table判断这个input_handler能否支持这个input_dev,如果可以则调用
input_handler的connect函数建立“连接”
怎么建立连接:
1,分配一个input_handle结构体
2,设置
input_handle.dev = input_dev;
input_handle.handler = input_handler;
3,注册
input_handler->h_list = &input_handle
input_dev->h_list = &input_handle
Evdev.c
evdev_connect()
evdev = kzalloc(sizeof(struct evdev), GFP_KERNEL); // 分配一个input_handle结构
// 设置
evdev->handle.dev = dev; // 指向input_dev结构体
evdev->handle.name = evdev->name; //
evdev->handle.handler = handler; // 指向input_handler结构体
evdev->handle.private = evdev;
error = input_register_handle(&evdev->handle); // 注册这个handle
怎么读按键:
app: read
---------------------------------------------
..............
evdev_read
// 无数据并且是非阻塞方式打开,则立刻返回。
if (client->head == client->tail && evdev->exist && (file->f_flags & O_NONBLOCK))
return -EAGAIN; // client缓冲,如果环形缓冲头和尾是一样。表示数据是空的。并且文件是以非阻塞方式打开
则再次尝试。
// 否则休眠
retval = wait_event_interruptible(evdev->wait // 如果是以阻塞方式打开则马上进入休眠。
client->head != client->tail || !evdev->exist);
谁来唤醒:
evdev_event事件里面唤醒
wake_up_interruptible(&evdev->wait);
evdev_event被谁来调用
怎么写符合输入子系统框架的驱动程序?
1,分配一个input_dev结构体
2,设置
3,注册
4,硬件相关的代码,比如在中断服务程序里面上报事件。
- /*
- * The input core
- *
- * Copyright (c) 1999-2002 Vojtech Pavlik
- */
- /*
- * This program is free software; you can redistribute it and/or modify it
- * under the terms of the GNU General Public License version 2 as published by
- * the Free Software Foundation.
- */
- #include <linux/init.h>
- #include <linux/input.h>
- #include <linux/module.h>
- #include <linux/random.h>
- #include <linux/major.h>
- #include <linux/proc_fs.h>
- #include <linux/seq_file.h>
- #include <linux/interrupt.h>
- #include <linux/poll.h>
- #include <linux/device.h>
- #include <linux/mutex.h>
- MODULE_AUTHOR("Vojtech Pavlik ");
- MODULE_DESCRIPTION("Input core");
- MODULE_LICENSE("GPL");
- #define INPUT_DEVICES 256
- static LIST_HEAD(input_dev_list);
- static LIST_HEAD(input_handler_list);
- static struct input_handler *input_table[8];
- /**
- * 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
- * See also input_inject_event()
- */
- void input_event(struct input_dev *dev, unsigned int type, unsigned int code, int value)
- {
- struct input_handle *handle;
- if (type > EV_MAX || !test_bit(type, dev->evbit))
- return;
- add_input_randomness(type, code, value);
- switch (type) {
- case EV_SYN:
- switch (code) {
- case SYN_CONFIG:
- if (dev->event)
- dev->event(dev, type, code, value);
- break;
- case SYN_REPORT:
- if (dev->sync)
- return;
- dev->sync = 1;
- break;
- }
- break;
- case EV_KEY:
- if (code > KEY_MAX || !test_bit(code, dev->keybit) || !!test_bit(code, dev->key) == value)
- return;
- if (value == 2)
- break;
- change_bit(code, dev->key);
- if (test_bit(EV_REP, dev->evbit) && dev->rep[REP_PERIOD] && dev->rep[REP_DELAY] && dev->timer.data && value) {
- dev->repeat_key = code;
- mod_timer(&dev->timer, jiffies + msecs_to_jiffies(dev->rep[REP_DELAY]));
- }
- break;
- case EV_SW:
- if (code > SW_MAX || !test_bit(code, dev->swbit) || !!test_bit(code, dev->sw) == value)
- return;
- change_bit(code, dev->sw);
- break;
- case EV_ABS:
- if (code > ABS_MAX || !test_bit(code, dev->absbit))
- return;
- if (dev->absfuzz[code]) {
- if ((value > dev->abs[code] - (dev->absfuzz[code] >> 1)) &&
- (value < dev->abs[code] + (dev->absfuzz[code] >> 1)))
- return;
- if ((value > dev->abs[code] - dev->absfuzz[code]) &&
- (value < dev->abs[code] + dev->absfuzz[code]))
- value = (dev->abs[code] * 3 + value) >> 2;
- if ((value > dev->abs[code] - (dev->absfuzz[code] << 1)) &&
- (value < dev->abs[code] + (dev->absfuzz[code] << 1)))
- value = (dev->abs[code] + value) >> 1;
- }
- if (dev->abs[code] == value)
- return;
- dev->abs[code] = value;
- break;
- case EV_REL:
- if (code > REL_MAX || !test_bit(code, dev->relbit) || (value == 0))
- return;
- break;
- case EV_MSC:
- if (code > MSC_MAX || !test_bit(code, dev->mscbit))
- return;
- if (dev->event)
- dev->event(dev, type, code, value);
- break;
- case EV_LED:
- if (code > LED_MAX || !test_bit(code, dev->ledbit) || !!test_bit(code, dev->led) == value)
- return;
- change_bit(code, dev->led);
- if (dev->event)
- dev->event(dev, type, code, value);
- break;
- case EV_SND:
- if (code > SND_MAX || !test_bit(code, dev->sndbit))
- return;
- if (!!test_bit(code, dev->snd) != !!value)
- change_bit(code, dev->snd);
- if (dev->event)
- dev->event(dev, type, code, value);
- break;
- case EV_REP:
- if (code > REP_MAX || value < 0 || dev->rep[code] == value)
- return;
- dev->rep[code] = value;
- if (dev->event)
- dev->event(dev, type, code, value);
- break;
- case EV_FF:
- if (value < 0)
- return;
- if (dev->event)
- dev->event(dev, type, code, value);
- break;
- }
- if (type != EV_SYN)
- dev->sync = 0;
- if (dev->grab)
- dev->grab->handler->event(dev->grab, type, code, value);
- else
- list_for_each_entry(handle, &dev->h_list, d_node)
- if (handle->open)
- handle->handler->event(handle, type, code, value);
- }
- 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)
- {
- if (!handle->dev->grab || handle->dev->grab == handle)
- input_event(handle->dev, type, code, value);
- }
- EXPORT_SYMBOL(input_inject_event);
- static void input_repeat_key(unsigned long data)
- {
- struct input_dev *dev = (void *) data;
- if (!test_bit(dev->repeat_key, dev->key))
- return;
- input_event(dev, EV_KEY, dev->repeat_key, 2);
- input_sync(dev);
- if (dev->rep[REP_PERIOD])
- mod_timer(&dev->timer, jiffies + msecs_to_jiffies(dev->rep[REP_PERIOD]));
- }
- int input_grab_device(struct input_handle *handle)
- {
- if (handle->dev->grab)
- return -EBUSY;
- handle->dev->grab = handle;
- return 0;
- }
- EXPORT_SYMBOL(input_grab_device);
- void input_release_device(struct input_handle *handle)
- {
- struct input_dev *dev = handle->dev;
- if (dev->grab == handle) {
- dev->grab = NULL;
- list_for_each_entry(handle, &dev->h_list, d_node)
- if (handle->handler->start)
- handle->handler->start(handle);
- }
- }
- EXPORT_SYMBOL(input_release_device);
- int input_open_device(struct input_handle *handle)
- {
- struct input_dev *dev = handle->dev;
- int err;
- err = mutex_lock_interruptible(&dev->mutex);
- if (err)
- return err;
- handle->open++;
- if (!dev->users++ && dev->open)
- err = dev->open(dev);
- if (err)
- handle->open--;
- mutex_unlock(&dev->mutex);
- return err;
- }
- EXPORT_SYMBOL(input_open_device);
- int input_flush_device(struct input_handle* handle, struct file* file)
- {
- if (handle->dev->flush)
- return handle->dev->flush(handle->dev, file);
- return 0;
- }
- EXPORT_SYMBOL(input_flush_device);
- void input_close_device(struct input_handle *handle)
- {
- struct input_dev *dev = handle->dev;
- input_release_device(handle);
- mutex_lock(&dev->mutex);
- if (!--dev->users && dev->close)
- dev->close(dev);
- handle->open--;
- mutex_unlock(&dev->mutex);
- }
- EXPORT_SYMBOL(input_close_device);
- static int input_fetch_keycode(struct input_dev *dev, int scancode)
- {
- switch (dev->keycodesize) {
- case 1:
- return ((u8 *)dev->keycode)[scancode];
- case 2:
- return ((u16 *)dev->keycode)[scancode];
- default:
- return ((u32 *)dev->keycode)[scancode];
- }
- }
- static int input_default_getkeycode(struct input_dev *dev,
- int scancode, int *keycode)
- {
- if (!dev->keycodesize)
- return -EINVAL;
- if (scancode < 0 || scancode >= dev->keycodemax)
- return -EINVAL;
- *keycode = input_fetch_keycode(dev, scancode);
- return 0;
- }
- static int input_default_setkeycode(struct input_dev *dev,
- int scancode, int keycode)
- {
- int old_keycode;
- int i;
- if (scancode < 0 || scancode >= dev->keycodemax)
- return -EINVAL;
- if (keycode < 0 || keycode > KEY_MAX)
- return -EINVAL;
- if (!dev->keycodesize)
- return -EINVAL;
- if (dev->keycodesize < sizeof(keycode) && (keycode >> (dev->keycodesize * 8)))
- return -EINVAL;
- switch (dev->keycodesize) {
- case 1: {
- u8 *k = (u8 *)dev->keycode;
- old_keycode = k[scancode];
- k[scancode] = keycode;
- break;
- }
- case 2: {
- u16 *k = (u16 *)dev->keycode;
- old_keycode = k[scancode];
- k[scancode] = keycode;
- break;
- }
- default: {
- u32 *k = (u32 *)dev->keycode;
- old_keycode = k[scancode];
- k[scancode] = keycode;
- break;
- }
- }
- clear_bit(old_keycode, dev->keybit);
- set_bit(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;
- }
- #define MATCH_BIT(bit, max) \
- for (i = 0; i < NBITS(max); i++) \
- if ((id->bit[i] & dev->bit[i]) != id->bit[i]) \
- break; \
- if (i != NBITS(max)) \
- continue;
- static const struct input_device_id *input_match_device(const struct input_device_id *id,
- struct input_dev *dev)
- {
- int i;
- for (; 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;
- MATCH_BIT(evbit, EV_MAX);
- MATCH_BIT(keybit, KEY_MAX);
- MATCH_BIT(relbit, REL_MAX);
- MATCH_BIT(absbit, ABS_MAX);
- MATCH_BIT(mscbit, MSC_MAX);
- MATCH_BIT(ledbit, LED_MAX);
- MATCH_BIT(sndbit, SND_MAX);
- MATCH_BIT(ffbit, FF_MAX);
- MATCH_BIT(swbit, SW_MAX);
- 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;
- if (handler->blacklist && input_match_device(handler->blacklist, dev))
- return -ENODEV;
- id = input_match_device(handler->id_table, dev);
- if (!id)
- return -ENODEV;
- error = handler->connect(handler, dev, id);
- if (error && error != -ENODEV)
- printk(KERN_ERR
- "input: failed to attach handler %s to device %s, "
- "error: %d\n",
- handler->name, kobject_name(&dev->cdev.kobj), error);
- return error;
- }
- #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)
- {
- int state = input_devices_state;
- poll_wait(file, &input_devices_poll_wait, wait);
- if (state != input_devices_state)
- return POLLIN | POLLRDNORM;
- return 0;
- }
- static struct list_head *list_get_nth_element(struct list_head *list, loff_t *pos)
- {
- struct list_head *node;
- loff_t i = 0;
- list_for_each(node, list)
- if (i++ == *pos)
- return node;
- return NULL;
- }
- static struct list_head *list_get_next_element(struct list_head *list, struct list_head *element, loff_t *pos)
- {
- if (element->next == list)
- return NULL;
- ++(*pos);
- return element->next;
- }
- static void *input_devices_seq_start(struct seq_file *seq, loff_t *pos)
- {
- /* acquire lock here ... Yes, we do need locking, I knowi, I know... */
- return list_get_nth_element(&input_dev_list, pos);
- }
- static void *input_devices_seq_next(struct seq_file *seq, void *v, loff_t *pos)
- {
- return list_get_next_element(&input_dev_list, v, pos);
- }
- static void input_devices_seq_stop(struct seq_file *seq, void *v)
- {
- /* release lock here */
- }
- static void input_seq_print_bitmap(struct seq_file *seq, const char *name,
- unsigned long *bitmap, int max)
- {
- int i;
- for (i = NBITS(max) - 1; i > 0; i--)
- if (bitmap[i])
- break;
- seq_printf(seq, "B: %s=", name);
- for (; i >= 0; i--)
- seq_printf(seq, "%lx%s", bitmap[i], i > 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->cdev.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, "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 struct seq_operations input_devices_seq_ops = {
- .start = input_devices_seq_start,
- .next = input_devices_seq_next,
- .stop = input_devices_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)
- {
- /* acquire lock here ... Yes, we do need locking, I knowi, I know... */
- seq->private = (void *)(unsigned long)*pos;
- return list_get_nth_element(&input_handler_list, pos);
- }
- static void *input_handlers_seq_next(struct seq_file *seq, void *v, loff_t *pos)
- {
- seq->private = (void *)(unsigned long)(*pos + 1);
- return list_get_next_element(&input_handler_list, v, pos);
- }
- static void input_handlers_seq_stop(struct seq_file *seq, void *v)
- {
- /* release lock here */
- }
- static int input_handlers_seq_show(struct seq_file *seq, void *v)
- {
- struct input_handler *handler = container_of(v, struct input_handler, node);
- seq_printf(seq, "N: Number=%ld Name=%s",
- (unsigned long)seq->private, handler->name);
- if (handler->fops)
- seq_printf(seq, " Minor=%d", handler->minor);
- seq_putc(seq, '\n');
- return 0;
- }
- static struct seq_operations input_handlers_seq_ops = {
- .start = input_handlers_seq_start,
- .next = input_handlers_seq_next,
- .stop = input_handlers_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("input", proc_bus);
- if (!proc_bus_input_dir)
- return -ENOMEM;
- proc_bus_input_dir->owner = THIS_MODULE;
- entry = create_proc_entry("devices", 0, proc_bus_input_dir);
- if (!entry)
- goto fail1;
- entry->owner = THIS_MODULE;
- entry->proc_fops = &input_devices_fileops;
- entry = create_proc_entry("handlers", 0, proc_bus_input_dir);
- if (!entry)
- goto fail2;
- entry->owner = THIS_MODULE;
- entry->proc_fops = &input_handlers_fileops;
- return 0;
- fail2: remove_proc_entry("devices", proc_bus_input_dir);
- fail1: remove_proc_entry("input", proc_bus);
- 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("input", proc_bus);
- }
- #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 class_device *dev, 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 CLASS_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[LONG(i)] & BIT(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 class_device *dev, 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 CLASS_DEVICE_ATTR(modalias, S_IRUGO, input_dev_show_modalias, NULL);
- static struct attribute *input_dev_attrs[] = {
- &class_device_attr_name.attr,
- &class_device_attr_phys.attr,
- &class_device_attr_uniq.attr,
- &class_device_attr_modalias.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 class_device *dev, char *buf) \
- { \
- struct input_dev *input_dev = to_input_dev(dev); \
- return scnprintf(buf, PAGE_SIZE, "%04x\n", input_dev->id.name); \
- } \
- static CLASS_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[] = {
- &class_device_attr_bustype.attr,
- &class_device_attr_vendor.attr,
- &class_device_attr_product.attr,
- &class_device_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;
- for (i = NBITS(max) - 1; i > 0; i--)
- if (bitmap[i])
- break;
- for (; i >= 0; i--)
- len += snprintf(buf + len, max(buf_size - len, 0),
- "%lx%s", bitmap[i], i > 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 class_device *dev, 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, 1); \
- return min_t(int, len, PAGE_SIZE); \
- } \
- static CLASS_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[] = {
- &class_device_attr_ev.attr,
- &class_device_attr_key.attr,
- &class_device_attr_rel.attr,
- &class_device_attr_abs.attr,
- &class_device_attr_msc.attr,
- &class_device_attr_led.attr,
- &class_device_attr_snd.attr,
- &class_device_attr_ff.attr,
- &class_device_attr_sw.attr,
- NULL
- };
- static struct attribute_group input_dev_caps_attr_group = {
- .name = "capabilities",
- .attrs = input_dev_caps_attrs,
- };
- static 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 class_device *class_dev)
- {
- struct input_dev *dev = to_input_dev(class_dev);
- input_ff_destroy(dev);
- kfree(dev);
- module_put(THIS_MODULE);
- }
- /*
- * Input uevent interface - loading event handlers based on
- * device bitfields.
- */
- static int input_add_uevent_bm_var(char **envp, int num_envp, int *cur_index,
- char *buffer, int buffer_size, int *cur_len,
- const char *name, unsigned long *bitmap, int max)
- {
- if (*cur_index >= num_envp - 1)
- return -ENOMEM;
- envp[*cur_index] = buffer + *cur_len;
- *cur_len += snprintf(buffer + *cur_len, max(buffer_size - *cur_len, 0), name);
- if (*cur_len >= buffer_size)
- return -ENOMEM;
- *cur_len += input_print_bitmap(buffer + *cur_len,
- max(buffer_size - *cur_len, 0),
- bitmap, max, 0) + 1;
- if (*cur_len > buffer_size)
- return -ENOMEM;
- (*cur_index)++;
- return 0;
- }
- static int input_add_uevent_modalias_var(char **envp, int num_envp, int *cur_index,
- char *buffer, int buffer_size, int *cur_len,
- struct input_dev *dev)
- {
- if (*cur_index >= num_envp - 1)
- return -ENOMEM;
- envp[*cur_index] = buffer + *cur_len;
- *cur_len += snprintf(buffer + *cur_len, max(buffer_size - *cur_len, 0),
- "MODALIAS=");
- if (*cur_len >= buffer_size)
- return -ENOMEM;
- *cur_len += input_print_modalias(buffer + *cur_len,
- max(buffer_size - *cur_len, 0),
- dev, 0) + 1;
- if (*cur_len > buffer_size)
- return -ENOMEM;
- (*cur_index)++;
- return 0;
- }
- #define INPUT_ADD_HOTPLUG_VAR(fmt, val...) \
- do { \
- int err = add_uevent_var(envp, num_envp, &i, \
- buffer, buffer_size, &len, \
- 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(envp, num_envp, &i, \
- buffer, buffer_size, &len, \
- name, bm, max); \
- if (err) \
- return err; \
- } while (0)
- #define INPUT_ADD_HOTPLUG_MODALIAS_VAR(dev) \
- do { \
- int err = input_add_uevent_modalias_var(envp, \
- num_envp, &i, \
- buffer, buffer_size, &len, \
- dev); \
- if (err) \
- return err; \
- } while (0)
- static int input_dev_uevent(struct class_device *cdev, char **envp,
- int num_envp, char *buffer, int buffer_size)
- {
- struct input_dev *dev = to_input_dev(cdev);
- int i = 0;
- int len = 0;
- 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("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);
- envp[i] = NULL;
- return 0;
- }
- struct class input_class = {
- .name = "input",
- .release = input_dev_release,
- .uevent = input_dev_uevent,
- };
- EXPORT_SYMBOL_GPL(input_class);
- /**
- * input_allocate_device - allocate memory for new input device
- *
- * Returns prepared struct input_dev or NULL.
- *
- * NOTE: Use input_free_device() to free devices that have not been
- * registered; input_unregister_device() should be used for already
- * registered devices.
- */
- struct input_dev *input_allocate_device(void)
- {
- struct input_dev *dev;
- dev = kzalloc(sizeof(struct input_dev), GFP_KERNEL);
- if (dev) {
- dev->cdev.class = &input_class;
- dev->cdev.groups = input_dev_attr_groups;
- class_device_initialize(&dev->cdev);
- mutex_init(&dev->mutex);
- INIT_LIST_HEAD(&dev->h_list);
- INIT_LIST_HEAD(&dev->node);
- __module_get(THIS_MODULE);
- }
- return dev;
- }
- EXPORT_SYMBOL(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
- * refrence 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)
- 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:
- __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;
- default:
- printk(KERN_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);
- int input_register_device(struct input_dev *dev)
- {
- static atomic_t input_no = ATOMIC_INIT(0);
- struct input_handler *handler;
- const char *path;
- int error;
- set_bit(EV_SYN, dev->evbit);
- /*
- * If delay and period are pre-set by the driver, then autorepeating
- * is handled by the driver itself and we don't do it in input.c.
- */
- init_timer(&dev->timer);
- 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;
- }
- if (!dev->getkeycode)
- dev->getkeycode = input_default_getkeycode;
- if (!dev->setkeycode)
- dev->setkeycode = input_default_setkeycode;
- list_add_tail(&dev->node, &input_dev_list);
- snprintf(dev->cdev.class_id, sizeof(dev->cdev.class_id),
- "input%ld", (unsigned long) atomic_inc_return(&input_no) - 1);
- if (!dev->cdev.dev)
- dev->cdev.dev = dev->dev.parent;
- error = class_device_add(&dev->cdev);
- if (error)
- return error;
- path = kobject_get_path(&dev->cdev.kobj, GFP_KERNEL);
- printk(KERN_INFO "input: %s as %s\n",
- dev->name ? dev->name : "Unspecified device", path ? path : "N/A");
- kfree(path);
- list_for_each_entry(handler, &input_handler_list, node)
- input_attach_handler(dev, handler);
- input_wakeup_procfs_readers();
- return 0;
- }
- EXPORT_SYMBOL(input_register_device);
- void input_unregister_device(struct input_dev *dev)
- {
- struct input_handle *handle, *next;
- int code;
- for (code = 0; code <= KEY_MAX; code++)
- if (test_bit(code, dev->key))
- input_report_key(dev, code, 0);
- input_sync(dev);
- del_timer_sync(&dev->timer);
- list_for_each_entry_safe(handle, next, &dev->h_list, d_node)
- handle->handler->disconnect(handle);
- WARN_ON(!list_empty(&dev->h_list));
- list_del_init(&dev->node);
- class_device_unregister(&dev->cdev);
- input_wakeup_procfs_readers();
- }
- EXPORT_SYMBOL(input_unregister_device);
- int input_register_handler(struct input_handler *handler)
- {
- struct input_dev *dev;
- INIT_LIST_HEAD(&handler->h_list);
- if (handler->fops != NULL) {
- if (input_table[handler->minor >> 5])
- return -EBUSY;
- input_table[handler->minor >> 5] = handler;
- }
- list_add_tail(&handler->node, &input_handler_list);
- list_for_each_entry(dev, &input_dev_list, node)
- input_attach_handler(dev, handler);
- input_wakeup_procfs_readers();
- return 0;
- }
- EXPORT_SYMBOL(input_register_handler);
- void input_unregister_handler(struct input_handler *handler)
- {
- struct input_handle *handle, *next;
- 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);
- if (handler->fops != NULL)
- input_table[handler->minor >> 5] = NULL;
- input_wakeup_procfs_readers();
- }
- EXPORT_SYMBOL(input_unregister_handler);
- int input_register_handle(struct input_handle *handle)
- {
- struct input_handler *handler = handle->handler;
- list_add_tail(&handle->d_node, &handle->dev->h_list);
- list_add_tail(&handle->h_node, &handler->h_list);
- if (handler->start)
- handler->start(handle);
- return 0;
- }
- EXPORT_SYMBOL(input_register_handle);
- void input_unregister_handle(struct input_handle *handle)
- {
- list_del_init(&handle->h_node);
- list_del_init(&handle->d_node);
- }
- EXPORT_SYMBOL(input_unregister_handle);
- static int input_open_file(struct inode *inode, struct file *file)
- { // 根据所打开文件的次设备号,得到一个input_handler
- struct input_handler *handler = input_table[iminor(inode) >> 5]; // 分配一个input_handler结构体
- const struct file_operations *old_fops, *new_fops = NULL;
- int err;
- /* No load-on-demand here? */
- if (!handler || !(new_fops = fops_get(handler->fops))) // new_fops与handler中的fops不一样则返回。
- return -ENODEV;
- /*
- * That's _really_ odd. Usually NULL ->open means "nothing special",
- * not "no device". Oh, well...
- */
- if (!new_fops->open) { // 如果新的fops中的open没有被打开。
- fops_put(new_fops); // 就将fpos放入新的fops中。
- return -ENODEV;
- } // 否则将新fops写入旧的fops中。
- old_fops = file->f_op;
- file->f_op = new_fops; // 将新的fops传入旧的fops
- err = new_fops->open(inode, file); // 返回新的fops
- if (err) { // 如果新的fops被打开
- fops_put(file->f_op);
- file->f_op = fops_get(old_fops);
- }
- fops_put(old_fops);
- return err; // 返回fops
- }
- static const struct file_operations input_fops = {
- .owner = THIS_MODULE,
- .open = input_open_file,
- };
- static int __init input_init(void)
- {
- int err;
- err = class_register(&input_class);
- if (err) {
- printk(KERN_ERR "input: unable to register input_dev class\n");
- return err;
- }
- err = input_proc_init();
- if (err)
- goto fail1;
- err = register_chrdev(INPUT_MAJOR, "input", &input_fops);
- if (err) {
- printk(KERN_ERR "input: 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(INPUT_MAJOR, "input");
- class_unregister(&input_class);
- }
- subsys_initcall(input_init);
- module_exit(input_exit);
要看一个驱动程序,首先要从入口函数开始看。