at91中断学习-linux2.6.30

 

http://blog.163.com/shaohj_1999@126/blog/static/6340685120103130036928/

 

经过两天的学习，终于搞定at91的输入中断了，明白后感觉很简单，真的~

       废话少说，开始说下所遇到的麻烦。刚开始，一直没有注意kernel中对at91的中断号定义与管脚定义是重复，中断号的寻找花了不少时间，原来在内核的 kernel/arch/arm/mach-at91/include/mach/gpio.h中 these pin numbers double as IRQ numbers, like AT91xxx_ID_* values这句话提醒了我。找到中断号后，在网上看了别人写好的程序，不过问题还是有的。他只介绍，没具体程序。无赖下只能用写这块程序了，其实也不难，在s3c2440基础上进行了修改便可。不过一定要注意正在使用的IO口是否被使用过。

        驱动程序如下：

#include <linux/miscdevice.h>
#include <asm/irq.h>
#include <mach/gpio.h>
#include <mach/hardware.h>
#include <linux/kernel.h>
#include <linux/module.h>
#include <linux/init.h>
#include <linux/mm.h>
#include <linux/fs.h>
#include <linux/types.h>
#include <linux/slab.h>
#include <linux/errno.h>
#include <linux/ioctl.h>
#include <linux/cdev.h>
#include <linux/string.h>
#include <linux/list.h>
#include <linux/pci.h>
#include <asm/uaccess.h>
#include <asm/atomic.h>
#include <asm/unistd.h>
#include<linux/module.h>
#include<linux/poll.h>
#include<linux/interrupt.h>


#define DEVICE_NAME "Timll-keys"

struct button_irq_desc
{
    int irq;
    int pin;
    int number;
    char *name;
};

static struct button_irq_desc button_irqs[]=
{
    {AT91_PIN_PA27,AT91_PIN_PA27,0,"KEY1"},
    {AT91_PIN_PA28,AT91_PIN_PA28,1,"KEY2"},
};

static volatile char key_values [] = {0,0};

static DECLARE_WAIT_QUEUE_HEAD(button_waitq);

static volatile int ev_press = 0;


static irqreturn_t button_interrupt(int irq, void *dev_id)
{
 struct button_irq_desc *button_irqs = (struct button_irq_desc *)dev_id;
 int down;

 down = !gpio_get_value(button_irqs->pin);

 if (down != (key_values[button_irqs->number] & 1))
 {
  key_values[button_irqs->number] = down;
  ev_press = 1;
  wake_up_interruptible(&button_waitq);
  printk("down=%d\n",down);
// printk("down key_values[0]=%c , key_values[1]=%c\n",key_values[0],key_values[1]);
 }
 return IRQ_RETVAL(IRQ_HANDLED);
}


static int irq_open(struct inode *inode, struct file *file)
{
    int err, i;
    for(i=0; i<sizeof(button_irqs)/sizeof(button_irqs[0]); i++) {
        at91_set_gpio_input(button_irqs[i].pin,1);
        gpio_to_irq(button_irqs[i].pin);
        err=request_irq(button_irqs[i].irq,button_interrupt,NULL,button_irqs[i].name,(void *)&button_irqs[i]);
        if(err) {
            i--;
            for(; i>=0; i--) {
                disable_irq(button_irqs[i].irq);
                free_irq(button_irqs[i].irq,(void *)&button_irqs[i]);
            }
            printk("open err");
            return -EBUSY;
        }
    }
    return 0;
}


static int irq_close(struct inode *inode, struct file *file)
{
 int i;
 for (i = 0; i < sizeof(button_irqs)/sizeof(button_irqs[0]); i++)
 {
  if (button_irqs[i].irq < 0)
   continue;
  free_irq(button_irqs[i].irq, (void *)&button_irqs[i]);
 }
 return 0;
}


static int irq_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
   wait_event_interruptible(button_waitq, ev_press);
 }
 ev_press = 0;
 err = copy_to_user(buff, (const void *)key_values, min(sizeof(key_values), count));
 return err ? -EFAULT : min(sizeof(key_values), count);
}


static struct file_operations dev_fops = {
 .owner = THIS_MODULE,
 .open = irq_open,
 .release =irq_close,
 .read = irq_read,
};

static struct miscdevice misc = {
 .minor = MISC_DYNAMIC_MINOR,
 .name = DEVICE_NAME,
 .fops = &dev_fops,
};

static char __initdata dis[]="[e-mail]\n";

static int __init dev_init(void)
{
 int ret;
 printk(dis);
 ret = misc_register(&misc);
 printk (DEVICE_NAME" initialized\n");
 return ret;
}

static void __exit dev_exit(void)
{
 misc_deregister(&misc);
}

module_init(dev_init);
module_exit(dev_exit);

MODULE_LICENSE("GPL");


测试程序网上只要read就行。

不明白QQ我，或者邮箱。