按键中断驱动

#include
#include
#include
#include
#include
#include
#include
#include
#include
#include
#include
//#include
//#include
#include
#include
#define DEVICE_NAME "EmbedSky-buttons"
#define BUTTON_MAJOR 232
struct button_irq_desc
{
  int irq;
  int pin;
  int pin_setting;
  int number;
  char *name;
};
static struct button_irq_desc button_irqs [] =
{
 
  {IRQ_EINT1, S3C2410_GPF1,S3C2410_GPF1_EINT1,0, "KEY1"},
  {IRQ_EINT4, S3C2410_GPF4,S3C2410_GPF4_EINT4,1, "KEY2"},
  {IRQ_EINT2, S3C2410_GPF2,S3C2410_GPF2_EINT2,2, "KEY3"},
  {IRQ_EINT0, S3C2410_GPF0,S3C2410_GPF0_EINT0,3, "KEY4"},
 };
static volatile int key_values[] = {0, 0, 0, 0};

/* 等待队列:
* 当没有按键被按下时，如果有进程调用 EmbedSky_buttons_read 函数，
* 它将休眠
*/
static DECLARE_WAIT_QUEUE_HEAD(button_waitq);

/* 中断事件标志, 中断服务程序将它置 1，EmbedSky_buttons_read 将它清 0 */
static volatile int ev_press = 0;
static irqreturn_t buttons_interrupt(int irq, void *dev_id)
{
  struct button_irq_desc *button_irqs = (struct button_irq_desc *)dev_id;
  int up = s3c2410_gpio_getpin(button_irqs->pin);
  if (up)
       key_values[button_irqs->number] = (button_irqs->number + 1) + 0x80;
  else
       key_values[button_irqs->number] = (button_irqs->number + 1);
  ev_press = 1;
 /* 表示中断发生了 */
 wake_up_interruptible(&button_waitq);
 /* 唤醒休眠的进程 */
 return IRQ_RETVAL(IRQ_HANDLED);
}
static int EmbedSky_buttons_open(struct inode *inode, struct file *file)
{
  int i;
  int err;
  for (i = 0; i < sizeof(button_irqs)/sizeof(button_irqs[0]); i++)
     {
     // 注册中断处理函数
     s3c2410_gpio_cfgpin(button_irqs[i].pin,button_irqs[i].pin_setting);
     err=request_irq(button_irqs[i].irq,buttons_interrupt,NULL,button_irqs[i].name,(void*)&button_irqs[i]);
     if (err)
             break;
      }
if (err)
     {
       // 释放已经注册的中断
       i--;
       for (; i >= 0; i--)
          {    disable_irq(button_irqs[i].irq);
               free_irq(button_irqs[i].irq, (void *)&button_irqs[i]);
           }
       return -EBUSY;
      }
return 0;
}
static int EmbedSky_buttons_close(struct inode *inode, struct file *file)
{
    int i;
    for (i = 0; i < sizeof(button_irqs)/sizeof(button_irqs[0]); i++)
     {
      // 释放已经注册的中断
      disable_irq(button_irqs[i].irq);
      free_irq(button_irqs[i].irq, (void *)&button_irqs[i]);
      }
    return 0;
}
static int EmbedSky_buttons_read(struct file *filp, char __user *buff, size_t count, loff_t *offp)
{
   unsigned long err;
   if (!ev_press)
      {
       if (filp->f_flags & O_NONBLOCK)
       return -EAGAIN;
       else
       /* 如果 ev_press 等于 0，休眠 */
       wait_event_interruptible(button_waitq, ev_press);
       }
       /* 执行到这里时，ev_press 等于 1，将它清 0 */
       ev_press = 0;
       /* 将按键状态复制给用户，并清 0 */
       err = copy_to_user(buff, (const void *)key_values, min(sizeof(key_values), count));
       memset((void *)key_values, 0, sizeof(key_values));
    return err ? -EFAULT : min(sizeof(key_values), count);
}
/**************************************************
* 当用户程序调用 select 函数时，本函数被调用
* 如果有按键数据，则 select 函数会立刻返回
* 如果没有按键数据，本函数使用 poll_wait 等待
**************************************************/
static unsigned int EmbedSky_buttons_poll( struct file *file, struct poll_table_struct *wait)
{
  unsigned int mask = 0;
  poll_wait(file, &button_waitq, wait);
  if (ev_press)
        mask |= POLLIN | POLLRDNORM;
  return mask;
}

static struct file_operations EmbedSky_buttons_fops =
{
 .owner=THIS_MODULE,
 .open    = EmbedSky_buttons_open,
 .release = EmbedSky_buttons_close,
 .read    = EmbedSky_buttons_read,
 .poll    = EmbedSky_buttons_poll,
 };
static char __initdata banner[] = "TQ2440/SKY2440 LEDS, (c) 2008,2009 www.embedsky.net\n";
static struct class *button_class;
static int __init EmbedSky_buttons_init(void)
{
  int ret;
  printk(banner);
  ret = register_chrdev(BUTTON_MAJOR, DEVICE_NAME, &EmbedSky_buttons_fops);
  if (ret < 0)
      {
        printk(DEVICE_NAME " can't register major number\n");
        return ret;
       }

  button_class = class_create(THIS_MODULE, DEVICE_NAME);
  if(IS_ERR(button_class))
    {
      printk("Err: failed in EmbedSky-leds class. \n");
      return -1;
    }
  device_create(button_class, NULL, MKDEV(BUTTON_MAJOR, 0), NULL, DEVICE_NAME);
  printk(DEVICE_NAME " initialized\n");
  return 0;
}
static void __exit EmbedSky_buttons_exit(void)
{
  unregister_chrdev(BUTTON_MAJOR, DEVICE_NAME);
  device_destroy(button_class, MKDEV(BUTTON_MAJOR, 0));
  class_destroy(button_class);
 }
module_init(EmbedSky_buttons_init);
module_exit(EmbedSky_buttons_exit);
MODULE_AUTHOR("http://www.embedsky.net");
MODULE_DESCRIPTION("TQ2440/SKY2440 LED Driver");
MODULE_LICENSE("GPL");