通常开发板自带按键中断的驱动，中断已被注册至内核。重新编译linux内核去掉自带驱动才能使用自己编写的驱动。
linux中断程序可分解为顶半部与底半部机制。顶半部完成尽可能少的紧急功能，底半部可以被新的中断打断。
驱动程序
#include <linux/module.h> #include <linux/kernel.h> #include <linux/fs.h> #include <linux/init.h> #include <linux/delay.h> #include <linux/poll.h> #include <linux/irq.h> #include <asm/irq.h> #include <linux/interrupt.h> #include <asm/uaccess.h> #include <mach/regs-gpio.h> #include <mach/hardware.h> #include <linux/platform_device.h> #include <linux/cdev.h> #include <linux/miscdevice.h> #include <linux/sched.h> #include <linux/gpio.h> #include <mach/gpio-bank-n.h> #define DEVICE_NAME "key_device" #define DEVICE_MAJOR 240 void key_tasklet_func(void); DECLARE_TASKLET(key_tasklet,key_tasklet_func,0); struct key_irq_desc { int irq; int pin; int pin_setting; int number; char *name; }; static struct key_irq_desc key_irqs [] = { {IRQ_EINT(0), S3C64XX_GPN(0) , S3C64XX_GPN0_EINT0 , 0, "KEY0"}, {IRQ_EINT(1), S3C64XX_GPN(1) , S3C64XX_GPN1_EINT1 , 1, "KEY1"}, {IRQ_EINT(2), S3C64XX_GPN(2) , S3C64XX_GPN2_EINT2 , 2, "KEY2"}, {IRQ_EINT(3), S3C64XX_GPN(3) , S3C64XX_GPN3_EINT3 , 3, "KEY3"}, {IRQ_EINT(4), S3C64XX_GPN(4) , S3C64XX_GPN4_EINT4 , 4, "KEY4"}, {IRQ_EINT(5), S3C64XX_GPN(5), S3C64XX_GPN5_EINT5 , 5, "KEY5"}, }; static volatile int key_values [] = {1, 1, 1, 1, 1, 1}; //初始化等待列对 static DECLARE_WAIT_QUEUE_HEAD(button_waitq); static volatile int event_flag = 0; static irqreturn_t buttons_interrupt(int irq, void *dev_id) { struct key_irq_desc *dev_irqs = (struct key_irq_desc *)dev_id; int down; down = gpio_get_value(dev_irqs->pin); //按键发生了变化 if (down != (key_values[dev_irqs->number] & 1)) { // Changed key_values[dev_irqs->number] = 0 + down; event_flag = 1; //唤醒列对 wake_up_interruptible(&button_waitq); } tasklet_schedule(&key_tasklet); return IRQ_RETVAL(IRQ_HANDLED); } void key_tasklet_func(void) { printk("<0>=======task======== "); printk("<0>task function test~ "); printk("<0>=================== "); } static int s3c6410_key_open(struct inode *inode, struct file *file) { int i; int err = 0; //注册中断 结构体未注册完 for (i = 0; i < sizeof(key_irqs)/sizeof(key_irqs[0]); i++) { if (key_irqs[i].irq < 0) { continue; } // 中断号 中断处理寒酸 中断处理属性 err = request_irq(key_irqs[i].irq, buttons_interrupt, IRQ_TYPE_EDGE_BOTH, key_irqs[i].name, (void *)&key_irqs[i]); if (err) break; } //如果注册中断过程中出错，则注销注册成功的中断 if (err) { i--; for (; i >= 0; i--) { if (key_irqs[i].irq < 0) { continue; } disable_irq(key_irqs[i].irq); free_irq(key_irqs[i].irq, (void *)&key_irqs[i]); } return -EBUSY; } //显示一次主界面而已 event_flag = 1; return 0; } static int s3c6410_keys_close(struct inode *inode, struct file *file) { int i; //注销中断 for (i = 0; i < sizeof(key_irqs)/sizeof(key_irqs[0]); i++) { if (key_irqs[i].irq < 0) { continue; } free_irq(key_irqs[i].irq, (void *)&key_irqs[i]); } return 0; } static int s3c6410_keys_read(struct file *filp, char __user *buff, size_t count, loff_t *offp) { unsigned long err; if (!event_flag) { //没有新按键事件处理，如果用户要求不阻塞就直接返回，否则阻塞在button_waitq队列上。 if (filp->f_flags & O_NONBLOCK) return -EAGAIN; else wait_event_interruptible(button_waitq, event_flag); } event_flag = 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 key_device_fops = { .owner = THIS_MODULE, .open = s3c6410_key_open, .release = s3c6410_keys_close, .read = s3c6410_keys_read, }; static int __init key_device_init(void) { int ret; printk ("<0>key init "); //注册字符设备 ret = register_chrdev(DEVICE_MAJOR,DEVICE_NAME,&key_device_fops); if (ret <0) { printk ("<0>register %s char dev error ","key"); return -1; } printk ("<0>success "); return 0; } static void __exit key_device_exit(void) { //注销设备 unregister_chrdev(DEVICE_MAJOR,DEVICE_NAME); printk ("<0>module exit "); } module_init(key_device_init); module_exit(key_device_exit); MODULE_LICENSE("GPL"); MODULE_AUTHOR("hebaichuan");
测试程序，按6键退出死循环。
#include <stdio.h> #include <stdlib.h> #include <unistd.h> #include <sys/ioctl.h> #define key_exit 5 int main(int argc, char **argv) { int fd,ret,i,key_value[6]; fd = open("/dev/key_device",0); if(fd<0) { printf("open devie error "); return -1; } while(1) { ret = read(fd,key_value, sizeof(key_value)); if(ret<0) { printf("read error "); continue; } else if(!key_value[key_exit]) exit(0); for(i=0;i<5;i++) { if(key_value[i]) { printf("KEY%d released ",(i+1),key_value[i]); } else { printf("KEY%d pressed ",(i+1),key_value[i]); } } printf("----------------key event---------------- "); } close(fd); return 0; }
运行结果：
