使用定時器實現按鍵防抖動

button.c

#include #include #include #include #include #include #include #include #include #include #include #include static struct class *sixthdrv_class;

static struct class_device *sixthdrv_class_dev;
volatile unsigned long *gpfcon;
volatile unsigned long *gpfdat;
volatile unsigned long *gpgcon;
volatile unsigned long *gpgdat;
static struct timer_list buttons_timer;
static declare_wait_queue_head(button_waitq);
/* 中斷事件標誌, 中斷服務程式將它置1，sixth_drv_read將它清0 */
static volatile int ev_press = 0;
static struct fasync_struct *button_async;
struct pin_desc;
/* 鍵值: 按下時, 0x01, 0x02, 0x03, 0x04 */
/* 鍵值: 鬆開時, 0x81, 0x82, 0x83, 0x84 */
static unsigned char key_val;
struct pin_desc pins_desc[4] = ,
, ,,};
static struct pin_desc *irq_pd;
//static atomic_t canopen = atomic_init(1); //定義原子變數並初始化為1
static declare_mutex(button_lock); //定義互斥鎖
/* * 確定按鍵值
*/static irqreturn_t buttons_irq(int irq, void *dev_id)
static int sixth_drv_open(struct inode *inode, struct file *file)
#endif 
if (file->f_flags & o_nonblock)
else
/* 配置gpf0,2為輸入引腳 */
/* 配置gpg3,11為輸入引腳 */
request_irq(irq_eint0, buttons_irq, irqt_bothedge, "s2", &pins_desc[0]);
request_irq(irq_eint2, buttons_irq, irqt_bothedge, "s3", &pins_desc[1]);
request_irq(irq_eint11, buttons_irq, irqt_bothedge, "s4", &pins_desc[2]);
request_irq(irq_eint19, buttons_irq, irqt_bothedge, "s5", &pins_desc[3]); 
return 0;
}ssize_t sixth_drv_read(struct file *file, char __user *buf, size_t size, loff_t *ppos)
else
/* 如果有按鍵動作, 返回鍵值 */
copy_to_user(buf, &key_val, 1);
ev_press = 0;
return 1;
}int sixth_drv_close(struct inode *inode, struct file *file)
static unsigned sixth_drv_poll(struct file *file, poll_table *wait)
static int sixth_drv_fasync (int fd, struct file *filp, int on)
static struct file_operations sencod_drv_fops = ;
int major;
static void buttons_timer_function(unsigned long data)
else
ev_press = 1; /* 表示中斷發生了 */
wake_up_interruptible(&button_waitq); /* 喚醒休眠的程序 */
kill_fasync (&button_async, sigio, poll_in);
}static int sixth_drv_init(void)
static void sixth_drv_exit(void)
module_init(sixth_drv_init);
module_exit(sixth_drv_exit);
module_license("gpl");

#include #include #include #include #include #include #include #include #include /* sixthdrvtest 

*/int fd;
void my_signal_fun(int signum)
int main(int argc, char **ar**)
//fcntl(fd, f_setown, getpid());
//oflags = fcntl(fd, f_getfl); 
//fcntl(fd, f_setfl, oflags | fasync);
while (1)
return 0;
}

kern_dir = /work/system/linux-2.6.22.6

all:
make -c $(kern_dir) m=`pwd` modules 
clean:
make -c $(kern_dir) m=`pwd` modules clean
rm -rf modules.order
obj-m += buttons.o

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