| 淺析linux下鍵盤設(shè)備工作和注冊流程
【淺析linux下鼠標(biāo)驅(qū)動的實現(xiàn)】
input_init()=>
=>
class_register(&input_class);注冊input類
input_proc_init();創(chuàng)建proc下的目錄和文件
register_chrdev(INPUT_MAJOR, "input", &input_fops);注冊驅(qū)動程序到cdev_map上,以待驅(qū)動設(shè)備.
drivers\input\keyboard\pxa3xx_keypad.c為我們的keyboard設(shè)備,
pxa3xx_keypad_probe=>
request_irq(IRQ_ENHROT, &enhanced_rotary_interrupt,
IRQF_DISABLED, "Enhanced Rotary", (void *)keypad);注冊快捷鍵中斷
request_irq(IRQ_KEYPAD, pxa3xx_keypad_interrupt, IRQF_DISABLED,pdev->name, keypad);注冊中斷
static irqreturn_t pxa3xx_keypad_interrupt(int irq, void *dev_id)
{
struct pxa3xx_keypad *keypad = dev_id;
uint32_t kpc = keypad_readl(KPC);
if (kpc & KPC_MI)
pxa3xx_keypad_scan_matrix(keypad);
if (kpc & KPC_DI)
pxa3xx_keypad_scan_direct(keypad);
return IRQ_HANDLED;
}
在irq中如果讀到了key,那么會直接調(diào)用
input_report_key(keypad->input_dev,lookup_matrix_keycode(keypad, row, col),
new_state[col] & (1 << row));
static inline unsigned int lookup_matrix_keycode(
struct pxa3xx_keypad *keypad, int row, int col)
{
return keypad->matrix_keycodes[(row << 3) + col];
}
input_report_key(struct input_dev *dev, unsigned int code, int value)
dev為input_dev設(shè)備,我們的4*4鍵盤
code為標(biāo)準(zhǔn)PC鍵盤碼值
value為按鍵動作,為1表示鍵盤按下,為0表示按鍵抬起
static inline void input_report_key(struct input_dev *dev, unsigned int code, int value)
{
input_event(dev, EV_KEY, code, !!value);
}
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)) {
spin_lock_irqsave(&dev->event_lock, flags);
add_input_randomness(type, code, value);//因為按鍵的存在隨機(jī)性,所以按鍵是給系統(tǒng)提供墑隨機(jī)數(shù)的好來源.
input_handle_event(dev, type, code, value);
spin_unlock_irqrestore(&dev->event_lock, flags);
}
}
static void input_handle_event(struct input_dev *dev,
unsigned int type, unsigned int code, int value)
{
...
case EV_KEY:
if (is_event_supported(code, dev->keybit, KEY_MAX) &&
!!test_bit(code, dev->key) != value) {//這次來的是否為新的鍵值
if (value != 2) {
__change_bit(code, dev->key);//通過異或^操作,反轉(zhuǎn)code對應(yīng)的bitmap,如果value等于2,那么將忽略該按鍵
if (value)
input_start_autorepeat(dev, code);//鍵盤按下,那么開啟定時檢測,這樣可以出現(xiàn)連續(xù)輸入的效果
}
disposition = INPUT_PASS_TO_HANDLERS;
}
break;
...
}
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,//重新啟動定時器input_repeat_key,時間間隔msecs_to_jiffies(dev->rep[REP_DELAY])
jiffies + msecs_to_jiffies(dev->rep[REP_DELAY]));
}
}
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)) {
input_pass_event(dev, EV_KEY, dev->repeat_key, 2);//交給處理按鍵函數(shù)
if (dev->sync) {
/*
* Only send SYN_REPORT if we are not in a middle
* of driver parsing a new hardware packet.
* Otherwise assume that the driver will send
* SYN_REPORT once it's done.
*/
input_pass_event(dev, EV_SYN, SYN_REPORT, 1);
}
if (dev->rep[REP_PERIOD])
mod_timer(&dev->timer, jiffies +
msecs_to_jiffies(dev->rep[REP_PERIOD]));
}
spin_unlock_irqrestore(&dev->event_lock, flags);
}
input_pass_event=>
handle->handler->event(handle, type, code, value);
就是kbd_handler的kbd_event=>kbd_keycode=>
atomic_notifier_call_chain(&keyboard_notifier_list, KBD_UNICODE, ¶m)
通知掛在keyboard鏈上所有等待鍵盤輸入的應(yīng)用程序,
通過register_keyboard_notifier()函數(shù)可以注冊到鍵盤鏈上【gliethttp.Leith】,
input_dev = input_allocate_device();申請一個input設(shè)備空間
input_dev->open = pxa3xx_keypad_open;給這個空間填充方法
input_dev->close = pxa3xx_keypad_close;
input_dev->private = keypad;
set_bit(EV_KEY, input_dev->evbit);//鍵按下
set_bit(EV_REL, input_dev->evbit);//鍵釋放
pxa3xx_keypad_build_keycode(keypad);//設(shè)備鍵盤映射碼
該函數(shù)將根據(jù)pxa3xx_device_keypad設(shè)備下的matrix_key_map進(jìn)行鍵控設(shè)置,
pxa_set_keypad_info(&jades_keypad_info)=>將jades_keypad_info登記為pdata;
#define MAX_MATRIX_KEY_NUM (8 * 8)
matrix_keycodes[MAX_MATRIX_KEY_NUM];表示為8*8鍵盤
keypad->matrix_keycodes[(row << 3) + col] = code;表示第row行的第col列處按鍵,代表code編碼值,這個為我們內(nèi)部使用.
set_bit(code, input_dev->keybit);//設(shè)置code為我們的鍵盤對操作系統(tǒng)可用的鍵盤值
if(pdata->direct_key_num) {
for (i = 0; i < pdata->direct_key_num; i++) {
set_bit(pdata->direct_key_map[i], input_dev->keybit);//快捷鍵單元
}
}
set_bit(KEY_POWER, input_dev->keybit);//登記電源按鍵為系統(tǒng)可見按鍵
input_register_device(input_dev);=>//注冊設(shè)該備devices_subsys總線上
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;//消抖處理函數(shù),采用延時消抖
dev->rep[REP_DELAY] = 500;//250;
dev->rep[REP_PERIOD] = 66;//33;
}
if (!dev->getkeycode)
dev->getkeycode = input_default_getkeycode;
if (!dev->setkeycode)
dev->setkeycode = input_default_setkeycode;
//在/sys/class/input下創(chuàng)建以input0,input1為目錄名的input類型設(shè)備
snprintf(dev->dev.bus_id, sizeof(dev->dev.bus_id),
"input%ld", (unsigned long) atomic_inc_return(&input_no) - 1);
if (dev->cdev.dev)
dev->dev.parent = dev->cdev.dev;
error = device_add(&dev->dev);//將設(shè)備登記到設(shè)備總線上,之后將以目錄和文件的形式呈現(xiàn)
if (error)
return error;
path = kobject_get_path(&dev->dev.kobj, GFP_KERNEL);
printk(KERN_INFO "input: %s as %s\n",
dev->name ? dev->name : "Unspecified device", path ? path : "N/A");
kfree(path);
error = mutex_lock_interruptible(&input_mutex);
if (error) {
device_del(&dev->dev);
return error;
}
list_add_tail(&dev->node, &input_dev_list);
//將設(shè)備放到input的鏈表上,該鏈表上存放著所有input類型的dev設(shè)備對象【gliethttp.Leith】
list_for_each_entry(handler, &input_handler_list, node)
input_attach_handler(dev, handler);
//從input_handler_list驅(qū)動鏈表上嘗試匹配,是否有驅(qū)動該dev設(shè)備的driver驅(qū)動,如果有,那么將匹配的驅(qū)動綁定給dev設(shè)備,來驅(qū)動這個dev.
input_wakeup_procfs_readers();
mutex_unlock(&input_mutex);
return 0;
}
drivers\char\keyboard.c
kbd_init()=>
input_register_handler(&kbd_handler); 注冊鍵盤驅(qū)動到input_handler_list鏈表上
static int input_attach_handler(struct input_dev *dev, struct input_handler *handler)
{
const struct input_device_id *id;
int error;
//看看這個咚咚,是不是在黑名單里,如果在,那么就byebye了【gliethttp.Leith】
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);//ok,找到驅(qū)動該dev的driver,那么嘗試連接
if (error && error != -ENODEV)
printk(KERN_ERR
"input: failed to attach handler %s to device %s, "
"error: %d\n",
handler->name, kobject_name(&dev->dev.kobj), error);
return error;
}
kbd_connect=>input_register_handle=>input_open_device=>pxa3xx_keypad_open配置鍵盤io口 |
