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LED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

内核代码

#include <linux/init.h>
#include <linux/module.h>
#include <linux/of.h>
#include <linux/of_gpio.h>
#include <linux/gpio.h>
#include <linux/interrupt.h>
#include <linux/of_irq.h>
struct device_node *dev_irq1;
struct device_node *dev_irq2;
struct device_node *dev_irq3;
struct device_node *dev_led1;
struct device_node *dev_led2;
struct device_node *dev_led3;
struct gpio_desc *gpio1no;
struct gpio_desc *gpio2no;
struct gpio_desc *gpio3no;
struct timer_list mytimer;
unsigned int irqno1,irqno2,irqno3;void mytimer_func(struct timer_list *timer)
{}
irqreturn_t myirq1_handler(int irq,void *dev)
{gpiod_set_value(gpio1no,!gpiod_get_value(gpio1no));return IRQ_HANDLED;
}
irqreturn_t myirq2_handler(int irq,void *dev)
{gpiod_set_value(gpio2no,!gpiod_get_value(gpio1no));return IRQ_HANDLED;
}
irqreturn_t myirq3_handler(int irq,void *dev)
{gpiod_set_value(gpio3no,!gpiod_get_value(gpio1no));return IRQ_HANDLED;
}
int major;
char kbuf[128]={0};unsigned int *vrcc;
int mycdev_open(struct inode *inode, struct file *file)
{printk("%s:%s:%d\n",__FILE__,__func__,__LINE__);return 0;
}
ssize_t mycdev_read(struct file *file, char  *ubuf, size_t size, loff_t *lof)
{printk("%s:%s:%d\n",__FILE__,__func__,__LINE__);unsigned long ret;//向用户空间读取拷贝if(size>sizeof(kbuf))//用户空间期待读取的大小内核满足不了，那就给内核支持的最大大小size=sizeof(kbuf);ret=copy_to_user(ubuf,kbuf,size);if(ret)//拷贝失败{printk("copy_to_user filed\n");return ret;}return 0;
}
ssize_t mycdev_write(struct file *file, const char  *ubuf, size_t size, loff_t *lof)
{unsigned long ret;//从用户空间读取数据if(size>sizeof(kbuf))//用户空间期待读取的大小内核满足不了，那就给内核支持的最大大小size=sizeof(kbuf);ret=copy_from_user(kbuf,ubuf,size);if(ret)//拷贝失败{printk("copy_to_user filed\n");return ret;}switch(kbuf[0]){case '1':if(kbuf[1]=='0')//关灯{gpiod_set_value(gpio1no,1);}else{gpiod_set_value(gpio1no,0);}break;case '2':if(kbuf[1]=='0')//关灯{gpiod_set_value(gpio2no,1);}else{gpiod_set_value(gpio2no,0);}break;case '3':if(kbuf[1]=='0')//关灯{gpiod_set_value(gpio3no,1);}else{gpiod_set_value(gpio3no,0);}break;}return 0;
}
int mycdev_close(struct inode *inode, struct file *file)
{printk("%s:%s:%d\n",__FILE__,__func__,__LINE__);return 0;
}//定义操作方法结构体变量并赋值
struct file_operations fops={.open=mycdev_open,.read=mycdev_read,.write=mycdev_write,.release=mycdev_close,
};static int __init mycdev_init(void)
{major=register_chrdev(0,"mycdev",&fops);if(major<0){printk("字符设备驱动注册失败\n");return major;}printk("字符设备驱动注册成功:major=%d\n",major);int ret1,ret2,ret3;dev_led1=of_find_node_by_path("/leds");if(dev_led1==NULL){printk("设备树解析失败\n");return -EFAULT;}printk("解析设备树成功\n");dev_irq1=of_find_node_by_path("/myirq");if(dev_irq1==NULL){printk("设备树解析失败\n");return -EFAULT;}printk("解析设备树成功\n");//led1gpio1no=gpiod_get_from_of_node(dev_led1,"led1-gpios",0,GPIOD_OUT_LOW,NULL);if(IS_ERR(gpio1no)){printk("gpio1对象申请失败\n");return -PTR_ERR(gpio1no);}printk("解析gpio1编号成功\n");//led2gpio2no=gpiod_get_from_of_node(dev_led1,"led2-gpios",0,GPIOD_OUT_LOW,NULL);if(IS_ERR(gpio2no)){printk("gpio2对象申请失败\n");return -PTR_ERR(gpio2no);}printk("解析gpio编号成功\n");//led3gpio3no=gpiod_get_from_of_node(dev_led1,"led3-gpios",0,GPIOD_OUT_LOW,NULL);if(IS_ERR(gpio3no)){printk("gpio1对象申请失败\n");return -PTR_ERR(gpio3no);}printk("解析gpio编号成功\n");//中断1irqno1=irq_of_parse_and_map(dev_irq1,0);if(!irqno1){printk("软中断解析失败\n");return -ENXIO;}printk("软中断解析成功 irqno1=%d\n",irqno1);ret1=request_irq(irqno1,myirq1_handler,IRQF_TRIGGER_FALLING,"key1",NULL);if(ret1){printk("注册中断失败\n");return ret1;}printk("注册中断成功\n");//中断2irqno2=irq_of_parse_and_map(dev_irq1,1);if(!irqno2){printk("软中断解析失败\n");return -ENXIO;}printk("软中断解析成功 irqno2=%d\n",irqno2);ret2=request_irq(irqno2,myirq2_handler,IRQF_TRIGGER_FALLING,"key1",NULL);if(ret2){printk("注册中断失败\n");return ret2;}printk("注册中断成功\n");//中断3irqno3=irq_of_parse_and_map(dev_irq1,2);if(!irqno3){printk("软中断解析失败\n");return -ENXIO;}printk("软中断解析成功 irqno3=%d\n",irqno3);ret3=request_irq(irqno3,myirq3_handler,IRQF_TRIGGER_FALLING,"key1",NULL);if(ret3){printk("注册中断失败\n");return ret3;}printk("注册中断成功\n");mytimer.expires=jiffies+HZ;timer_setup(&mytimer,mytimer_func,0);add_timer(&mytimer);return 0;
}
static void __exit mycdev_exit(void)
{del_timer(&mytimer);gpiod_set_value(gpio1no,0);gpiod_set_value(gpio2no,0);gpiod_set_value(gpio3no,0);gpiod_put(gpio1no);gpiod_put(gpio2no);gpiod_put(gpio3no);free_irq(irqno1,NULL);free_irq(irqno2,NULL);free_irq(irqno3,NULL);}
module_init(mycdev_init);
module_exit(mycdev_exit);
MODULE_LICENSE("GPL");

应用

#include<stdlib.h>
#include<stdio.h>
#include <sys/types.h>
#include <sys/stat.h>
#include <fcntl.h>
#include<unistd.h>
#include<string.h>
#include "/home/ubuntu/DC22111/char/head.h"
#include <sys/ioctl.h>int main(int argc, char const *argv[])
{char buf[128]={0};int fd=open("/dev/mycdev",O_RDWR);if(fd<0){printf("打开设备文件失败\n");exit(-1);}int a,b,c;while(1){//从终端读取printf("请输入1(灯光))>");scanf("%d",&a);if(a==1){printf("请输入功能:1(开灯),2(关灯)");scanf("%d",&b);if(b==1){printf("请输入要操作的灯光1,2,3>");scanf("%d",&c);ioctl(fd,LED_ON,&c);}else{printf("请输入要操作的灯光1,2,3>");scanf("%d",&c);ioctl(fd,LED_OFF,&c);}}}close(fd);return 0;
}