老习惯先贴一波代码再仔细分析消化。

#include <linux/module.h>
#include <linux/kernel.h>
#include <linux/fs.h>
#include <linux/init.h>
#include <linux/delay.h>
#include <linux/irq.h>
#include <asm/uaccess.h>
#include <asm/irq.h>
#include <asm/io.h>
#include <asm/arch/regs-gpio.h>
#include <asm/hardware.h>static struct class *thirddrv_class;
static struct class_device	*thirddrv_class_dev;volatile unsigned long *gpfcon;
volatile unsigned long *gpfdat;volatile unsigned long *gpgcon;
volatile unsigned long *gpgdat;static DECLARE_WAIT_QUEUE_HEAD(button_waitq);/* 中断事件标志, 中断服务程序将它置1，third_drv_read将它清0 */
static volatile int ev_press = 0;struct pin_desc{unsigned int pin;unsigned int key_val;
};/* 键值: 按下时, 0x01, 0x02, 0x03, 0x04 */
/* 键值: 松开时, 0x81, 0x82, 0x83, 0x84 */
static unsigned char key_val;struct pin_desc pins_desc[4] = {{S3C2410_GPF0, 0x01},{S3C2410_GPF2, 0x02},{S3C2410_GPG3, 0x03},{S3C2410_GPG11, 0x04},
};/** 确定按键值*/
static irqreturn_t buttons_irq(int irq, void *dev_id)
{struct pin_desc * pindesc = (struct pin_desc *)dev_id;unsigned int pinval;pinval = s3c2410_gpio_getpin(pindesc->pin);if (pinval){/* 松开 */key_val = 0x80 | pindesc->key_val;}else{/* 按下 */key_val = pindesc->key_val;}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 third_drv_open(struct inode *inode, struct file *file)
{/* 配置GPF0,2为输入引脚 *//* 配置GPG3,11为输入引脚 */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 third_drv_read(struct file *file, char __user *buf, size_t size, loff_t *ppos)
{if (size != 1)return -EINVAL;/* 如果没有按键动作, 休眠 */wait_event_interruptible(button_waitq, ev_press);/* 如果有按键动作, 返回键值 */copy_to_user(buf, &key_val, 1);ev_press = 0;return 1;
}int third_drv_close(struct inode *inode, struct file *file)
{free_irq(IRQ_EINT0, &pins_desc[0]);free_irq(IRQ_EINT2, &pins_desc[1]);free_irq(IRQ_EINT11, &pins_desc[2]);free_irq(IRQ_EINT19, &pins_desc[3]);return 0;
}static struct file_operations sencod_drv_fops = {.owner   =  THIS_MODULE,    /* 这是一个宏，推向编译模块时自动创建的__this_module变量 */.open    =  third_drv_open,     .read	 =	third_drv_read,	   .release =  third_drv_close,	   
};int major;
static int third_drv_init(void)
{major = register_chrdev(0, "third_drv", &sencod_drv_fops);thirddrv_class = class_create(THIS_MODULE, "third_drv");thirddrv_class_dev = class_device_create(thirddrv_class, NULL, MKDEV(major, 0), NULL, "buttons"); /* /dev/buttons */gpfcon = (volatile unsigned long *)ioremap(0x56000050, 16);gpfdat = gpfcon + 1;gpgcon = (volatile unsigned long *)ioremap(0x56000060, 16);gpgdat = gpgcon + 1;return 0;
}static void third_drv_exit(void)
{unregister_chrdev(major, "third_drv");class_device_unregister(thirddrv_class_dev);class_destroy(thirddrv_class);iounmap(gpfcon);iounmap(gpgcon);return 0;
}module_init(third_drv_init);module_exit(third_drv_exit);MODULE_LICENSE("GPL");

应用层代码如下

——————————————————————————————————————我是漂亮的分割线—————————————————————————

 

#include <sys/types.h>
#include <sys/stat.h>
#include <fcntl.h>
#include <stdio.h>
#include <unistd.h>/* thirddrvtest */
int main(int argc, char **argv)
{int fd;unsigned char key_val;fd = open("/dev/buttons", O_RDWR);if (fd < 0){printf("can't open!\n");}while (1){//read(fd, &key_val, 1);//printf("key_val = 0x%x\n", key_val);sleep(5);}return 0;
}