编写LED灯的驱动，使用GPIO子系统，里面添加按键的中断处理

1.应用程序发送指令控制发光二极管亮灭

2.按键1按下，led1电位反转；按键2按下，led2电位反转；按键3按下，led3电位反转 
 

//头文件
#ifndef __LED_H__
#define __LED_H__//功能码
#define LED_ON _IOW('l',1,int)
#define LED_OFF _IOW('l',0,int)
#endif

//应用程序实现LED的亮灭
#include <stdio.h>
#include <string.h>
#include <stdlib.h>
#include <sys/types.h>
#include <sys/stat.h>
#include <sys/ioctl.h>
#include <fcntl.h>
#include <unistd.h>
#include "led.h"
int main(int argc, const char *argv[])
{int a,b;while(1){int fd_led = open("/dev/myled0",O_RDWR);	if(fd_led < 0){printf("打开设备文件失败\n");exit(-1);}printf("请输入要控制的灯:1 2 3>>");scanf("%d",&b);printf("输入控制命令:0熄灭 1开灯>>>");scanf("%d",&a);switch(a){case 1:ioctl(fd_led,LED_ON,&b);break;case 0:ioctl(fd_led,LED_OFF,&b);break;}close(fd_led);}return 0;
}

//驱动程序
#include <linux/init.h>
#include <linux/module.h>
#include <linux/of.h>
#include <linux/of_gpio.h>
#include <linux/gpio.h>
#include <linux/device.h>
#include <linux/cdev.h>
#include <linux/slab.h>
#include <linux/fs.h>
#include <linux/io.h>
#include<linux/of_irq.h>
#include<linux/interrupt.h>
#include "led.h"
/*  leds{led1-gpios=<&gpioe 10 0>;//10表示引脚编号  0表示默认led2-gpios=<&gpiof 10 0>;led3-gpios=<&gpioe 8 0>;};*/
struct device_node *dnode1;
struct device_node *dnode2;
struct gpio_desc *gpiono1;
struct gpio_desc *gpiono2;
struct gpio_desc *gpiono3;
struct cdev *cdev;
int major=168;
int minor=0;
struct class *cls;
struct device *dev;
dev_t devno;
int i;
unsigned int irqno[3];      //软中断号//中断处理函数
irqreturn_t myirq_handler(int irqno, void *dev_id)
{unsigned int id=(unsigned int)dev_id;switch(id){case 0:printk("KEY1_INTERRUPT\n");gpiod_set_value(gpiono1,!gpiod_get_value(gpiono1));break;case 1:printk("KEY2_INTERRUPT\n");gpiod_set_value(gpiono2,!gpiod_get_value(gpiono2));break;case 2:printk("KEY3_INTERRUPT\n");gpiod_set_value(gpiono3,!gpiod_get_value(gpiono3));break;}return IRQ_HANDLED;
}
/*********************封装操作方法***************************/
int mycdev_open(struct inode *inode, struct file *file)
{//printk("%s:%s:%d\n", __FILE__, __func__, __LINE__);return 0;
}long mycdev_ioctl(struct file *file, unsigned int cmd, unsigned long arg)
{int which;copy_from_user(&which,(void *)arg,4);switch(cmd){case LED_ON:         // 亮灯switch(which){case 1:   gpiod_set_value(gpiono1, 1);break;case 2:gpiod_set_value(gpiono2, 1);break;case 3:gpiod_set_value(gpiono3, 1);break;}break;case LED_OFF:switch(which){case 1:gpiod_set_value(gpiono1, 0);break;case 2:gpiod_set_value(gpiono2, 0);break;case 3:gpiod_set_value(gpiono3, 0);}break;}//printk("%s:%s:%d\n", __FILE__, __func__, __LINE__);return 0;
}int mycdev_close(struct inode *inode, struct file *file)
{//printk("%s:%s:%d\n", __FILE__, __func__, __LINE__);return 0;
}
/***********************************************************************///定义一个操作方法结构体变量并初始化
struct file_operations fops =
{.open    =  mycdev_open,.release =  mycdev_close,.unlocked_ioctl = mycdev_ioctl,
};
static int __init mycdev_init(void)
{int ret,i;//1.申请对象空间 cdev_alloccdev = cdev_alloc();if(cdev == NULL){printk("申请对象空间失败\n");ret=-EFAULT;goto out1;}printk("申请对象空间成功\n");//2.初始化对象 cdev_initcdev_init(cdev,&fops);printk("初始化对象成功\n");//3.申请设备号 register_chrdev_region()或clloc_chrdev_region()if(major != 0)  //静态申请{ret=register_chrdev_region(MKDEV(major,minor),3,"myled");if(ret){printk("申请静态设备号失败\n");goto out2;}printk("申请静态设备号成功major=%d\n",major);}else    //动态申请{ret=alloc_chrdev_region(&devno,minor,3,"myled");if(ret){printk("申请动态设备号失败\n");goto out2;}major=MAJOR(devno);minor=MINOR(devno);printk("申请动态设备号成功major=%d\n",major);}//4.注册驱动对象 cdev_add()ret=cdev_add(cdev,MKDEV(major,minor),3);if(ret){printk("注册驱动对象失败\n");goto out3;}printk("注册驱动对象成功\n");//5.向上提交目录 class_create()cls=class_create(THIS_MODULE,"myled");if(IS_ERR(cls)){printk("向上提交目录失败\n");ret = -PTR_ERR(cls);goto out4;}printk("向上提交目录成功\n");//6.向上提交设备信息 device_create()for(i=0;i<3;i++){dev=device_create(cls,NULL,MKDEV(major,i),NULL,"myled%d",i);if(IS_ERR(dev)){printk("向上提交设备节点失败\n");ret = -PTR_ERR(dev);goto out5;}}printk("向上提交设备信息成功\n");// 根据设备树节点的路径解析设备树信息dnode1 = of_find_node_by_path("/leds");if (dnode1 == NULL){printk("解析设备树节点led失败\n");return -EFAULT;}printk("解析设备树节点led成功\n");// 申请gpio_desc对象并设置输出为低电平gpiono1 = gpiod_get_from_of_node(dnode1, "led1-gpios", 0, GPIOD_OUT_LOW, NULL);if (IS_ERR(gpiono1)){printk("申请gpio1对象失败\n");return -PTR_ERR(gpiono1);}printk("申请gpio1对象成功\n");gpiono2 = gpiod_get_from_of_node(dnode1, "led2-gpios", 0, GPIOD_OUT_LOW, NULL);if (IS_ERR(gpiono2)){printk("申请gpio2对象失败\n");return -PTR_ERR(gpiono2);}printk("申请gpio2对象成功\n");gpiono3 = gpiod_get_from_of_node(dnode1, "led3-gpios", 0, GPIOD_OUT_LOW, NULL);if (IS_ERR(gpiono3)){printk("申请gpio3对象失败\n");return -PTR_ERR(gpiono3);}printk("申请gpio3对象成功\n");// 根据设备树节点的路径解析设备树信息dnode2 = of_find_node_by_path("/myirq");if (dnode2 == NULL){printk("解析设备树节点myirq失败\n");return -EFAULT;}printk("解析设备树节点myirq成功\n");for(i=0;i<3;i++){//获取软中断号irqno[i]=irq_of_parse_and_map(dnode2,i);if(!irqno[i]){printk("软中断号irqno[%d]获取失败\n",i);return -ENXIO;}printk("软中断号获取成功irqno[%d]=%d\n",i,irqno[i]);//注册中断ret=request_irq(irqno[i],myirq_handler,IRQF_TRIGGER_FALLING,"key",(void *)i);if(ret){printk("注册驱动失败\n");return ret;}printk("key%d中断注册成功\n",i);}return 0;
out5:for(--i;i>=0;i--){//销毁上面提交的设备信息device_destroy(cls,MKDEV(major,i));}class_destroy(cls);
out4:cdev_del(cdev);
out3:unregister_chrdev_region(MKDEV(major,minor),3);
out2:kfree(cdev);
out1:return ret;
}
static void __exit mycdev_exit(void)
{// 灭灯gpiod_set_value(gpiono1, 0);gpiod_set_value(gpiono2, 0);gpiod_set_value(gpiono3, 0);// 释放gpio编号gpiod_put(gpiono1);gpiod_put(gpiono2);gpiod_put(gpiono3);//注销中断for(i=0;i<3;i++){free_irq(irqno[i],NULL);}
}
module_init(mycdev_init);
module_exit(mycdev_exit);
MODULE_LICENSE("GPL");