s5pv210中断法控制LED灯

前面介绍过轮询的方法控制LED灯，这里将介绍如何使用按键产生中断的方法控制LED灯。

linux内核的中断需要使用request_irq函数来申请，并用free_irq来释放它，在此就不介绍它的原理，下面将直接讲如何使用它们来完成中断操作，首先查看request_irq的原型，如下：

1、static inline int __must_check request_irq(unsigned int irq, irq_handler_t handler, unsigned long flags，const char *name, void *dev)

其中__must_check是提醒工程师在使用这个函数后最好检查其返回值，以确保申请中断成功，以下对各参数作介绍：

参数1：irq表示中断号，这个与芯片直接相关，不能随便定义，应该与硬件的中断号相对应;

参数2:代表一个函数指针，其实就是一个中断回调函数，当发生中断时会调用这个函数进行相应操作，它的原型为static irqreturn_t （*handler）(int irq, void *dev)，其中irq对应到request_irq的参数1，代表执行的哪个中断号的中断，因为有些中断会共享同一个中断，如IO口的中断，*dev对应于request_irq的最后一个参数，用于传递        参数给    回调函数。

       参数3：代表这个中断发生的标志，如IO口的中断有上升沿触发或下降沿触发等等

       参数4：中断的名字，通过cat /proc/interrupts 查找

       参数5：用于传递给中断回调函数的参数

       2、void free_irq(unsigned int irq, void *dev_id)

        释放中断，一般在结束时释放它irq对应于request_irq第一个参数，第二个对应于request_irq的最后一个参数。

      

      首先让我们查看原理图按键部分

      

     由原理图可知KEY1对应于XEINT0，则通过查芯片手册可知其对应的中断号为XIENT[0],其它按键同理可查，在以前的基础上改写驱动可得

#include <linux/module.h>#include <linux/kernel.h>#include <linux/fs.h>#include <linux/init.h>#include <linux/delay.h>#include <asm/uaccess.h>#include <linux/gpio.h> #include <asm/irq.h>#include <linux/sched.h>   #include <linux/irq.h>#include <asm/io.h>#include <linux/device.h>#include <linux/interrupt.h>#include <linux/wait.h>#include <linux/cdev.h>typedef struct {struct cdev cdev;dev_t devno;struct class *leddrv_class;struct device*leddrv_class_dev;int irq;int major;unsigned long virt;}CharLedDrive;static CharLedDrive led_info;static volatile int press = 0; struct pin_desc{unsigned int pin;unsigned char key_val;};static unsigned char witch_key = 0;static struct pin_desc key_descs[8] ={     [0] = {         .pin = S5PV210_GPH0(0),         .key_val = 0x01,     },     [1] = {         .pin = S5PV210_GPH0(1),         .key_val = 0x02,     },      [2] = {         .pin = S5PV210_GPH0(2),         .key_val = 0x03,     },      [3] = {         .pin = S5PV210_GPH0(3),         .key_val = 0x04,     },      [4] = {         .pin = S5PV210_GPH0(4),         .key_val = 0x05,     },      [5] = {         .pin = S5PV210_GPH0(5),         .key_val = 0x06,     },      [6] = {         .pin = S5PV210_GPH2(6),         .key_val = 0x07,     },      [7] = {         .pin = S5PV210_GPH2(7),         .key_val = 0x08,     },  };volatile unsigned long *GPC0CON, *GPC0DAT;//用与存放两个个寄存器的地址volatile unsigned long *GPH0CON, *GPH0DAT;//按键static unsigned char KeyFlag;static void all_leds_off(void);static void led_config(void){volatile unsigned long  phys;//用于存放虚拟地址和物理地址phys = 0xE0200060; led_info.virt =(unsigned long)ioremap(phys, 0xf00);GPC0CON = (unsigned long *)(led_info.virt + 0x00);//指定需要操作的三个寄存器的地址GPC0DAT = (unsigned long *)(led_info.virt + 0x04);GPH0CON = (unsigned long *)(led_info.virt + 0xc00-0x60); //keY1配置为输入GPH0DAT = (unsigned long *)(led_info.virt + 0xc00-0x60+0x04);*GPC0CON &= ~(0xFF << 12);*GPC0CON |= 0x11 << 12;// 配置GPC0_3和GPC0_4为输出*GPH0CON &= ~0x0F; //配置为输入all_leds_off();}static void led1_on(void){*GPC0DAT |= 1 << 3;*GPC0DAT &= ~(0x01 << 4);//printk("led1 light\n");}static void led2_on(void){*GPC0DAT |= 1 << 4;*GPC0DAT &= ~(0x01 << 3);//printk("led2 light\n");}static void all_leds_on(void){*GPC0DAT |= 1 << 3;// 点亮LED1*GPC0DAT |= 1 << 4;// 点亮LED2printk("all leds light\n");}static void all_leds_off(void){*GPC0DAT &= ~(0x3 << 3);// 熄灭LED1和LED2printk("all leds off\n");}static int led_drv_open(struct inode *inode, struct file *file){printk("led_drv_open\n");led_config();all_leds_off();return 0;}static irqreturn_t led_handler(int irq, void *devid){struct pin_desc * pindesc = (struct pin_desc *)devid;witch_key = pindesc->key_val;KeyFlag = !KeyFlag;printk("KERNEL:irq == %d  witch_key= %d\n",irq,witch_key);return IRQ_RETVAL(IRQ_HANDLED); }static ssize_t led_drv_write(struct file *file, const char __user *buf, size_t count, loff_t * ppos){char val = 0;int ret = -1;ret = copy_from_user(&val, buf, count);if(ret){printk("write ret= %x\n",ret);}return count;}static ssize_t led_drv_read(struct file *file, char __user *buf, size_t count, loff_t *ppos){int ret = -1;unsigned char from[1]={0};if(KeyFlag){   led1_on();}else{led2_on();}from[0] = witch_key;if(witch_key>0){ret = copy_to_user(buf,from,sizeof(from));if(ret){ printk("copy to user failed\n");}witch_key = 0;}return 0;}static struct file_operations led_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   =   led_drv_open,     .write=led_drv_write,.read= led_drv_read,   };//static irqreturn_t led_handler(int irq, void *dev_id)static int led_drv_init(void){int ret = -1;int i;cdev_init(&led_info.cdev, &led_drv_fops); //led_info.major = register_chrdev(0, "led_drv", &led_drv_fops); // 注册, 告诉内核led_info.cdev.owner = THIS_MODULE; ret = alloc_chrdev_region(&led_info.devno, 0, 1, "led_drv");   if(ret){      printk(KERN_ERR "alloc char device region faild!\n");      return ret;   }   ret = cdev_add(&led_info.cdev, led_info.devno, 1);   if(ret){       printk(KERN_ERR "add char device faild!\n");       goto cdev_add_error;     } led_info.leddrv_class = class_create(THIS_MODULE, "led_class_drv");if(IS_ERR(led_info.leddrv_class)){       printk(KERN_ERR "function class_create excute error!\n");       goto led_class_error;     } led_info.leddrv_class_dev = device_create(led_info.leddrv_class, NULL, led_info.devno, NULL, "led_drv"); /* /dev/xyz */if(IS_ERR(led_info.leddrv_class_dev)){       printk(KERN_ERR "function device_create excute error!\n");       goto led_device_error;     }   for(i=0;i<5;i++)  {ret = request_irq(IRQ_EINT(i), &led_handler, IRQ_TYPE_EDGE_FALLING,"led_irq",  &key_descs[i]);if(ret){printk(KERN_ERR"function request_irq(%d) excute error\n",i);goto led_request_irq_error;}}return 0;led_request_irq_error:device_unregister(led_info.leddrv_class_dev);led_device_error:class_destroy(led_info.leddrv_class); led_class_error:cdev_del(&led_info.cdev);cdev_add_error:unregister_chrdev_region(led_info.devno,1); return -ENODEV;}static void led_drv_exit(void){free_irq(IRQ_EINT(0), &key_descs[0]);free_irq(IRQ_EINT(1), &key_descs[1]);free_irq(IRQ_EINT(2), &key_descs[2]);free_irq(IRQ_EINT(3), &key_descs[3]);free_irq(IRQ_EINT(4), &key_descs[4]);printk("led_drv_exit ....excute ok\n");//all_leds_off();printk("led_drv_exit ....excute ok0\n");device_unregister(led_info.leddrv_class_dev);printk("led_drv_exit ....excute ok1\n");class_destroy(led_info.leddrv_class);printk("led_drv_exit ....excute ok2\n");cdev_del(&led_info.cdev); printk("led_drv_exit ....excute ok3\n");unregister_chrdev_region(led_info.devno, 1); printk("led_drv_exit ....excute ok4\n");iounmap((void *)led_info.virt); //撤销映射关系}module_init(led_drv_init);module_exit(led_drv_exit);MODULE_LICENSE("GPL");

测试程序如下：

#include<stdio.h>#include<stdlib.h>#include<sys/types.h>#include<sys/stat.h>#include<fcntl.h>#include <unistd.h>int main(int argc,char **argv){    int fd = -1;    char val = 0;    char buf[10]={0};    char temp= 0;    char *s = malloc(100);    unsigned char key[1];    fd = open("/dev/led_drv",O_RDWR);    if(fd<0)printf("can't open \n");while(1){val++;  if(read(fd,key,sizeof(key))>0){  temp = key[0];  if(temp)   printf("pressed key is key[%x]\n",temp);  temp = 0;}}free(s);    return 0;}