驱动应用层代码

#include <stdio.h>
#include <stdlib.h>
#include <sys/types.h>
#include <sys/stat.h>
#include <fcntl.h>
#include <unistd.h>
#include <string.h>
#include <sys/ioctl.h>
#include "head.h"

int main(int argc, char const *argv[])
{
    int a, b;
    char buf[128] = {0};

    int fd_led1 = open("/dev/led0", O_RDWR); //对应key1按键
    if (fd_led1 < 0)
    {
        printf("打开LED1设备文件失败\n");
        exit(-1);
    }

    while (1)
    {
        // 从终端读取
        printf("请选择KEY1灯功能\n");
        printf("0(关) 1(开)>");
        scanf("%d", &a);
        printf("请输入要控制的按键\n");
        printf("1(KEY1) 2(KEY2) 3(KEY3)>");
        scanf("%d", &b);
        if (a == 1) // 开灯
        {
			switch (b)
			{
			case 1:
				while(1){
           	    //ioctl(fd_led1, LED_ON, b);
           	    //ioctl(fd_led1, LED_ON, b);
				//memset(buf,0,sizeof(buf));//清空
       				read(fd_led1,buf,sizeof(buf));//读取数据
        			printf("number:%c\n",buf[0]);
					sleep(1);
				}

				break;
			case 2:
           	    //ioctl(fd_led2, LED_ON, b);
				break;
			case 3:
           	   // ioctl(fd_led3, LED_ON, b);
				break;
			}
        }
        else if (a == 0) // 关灯
        {			
			switch (b)
			{
			case 1:
           	    //ioctl(fd_led1, LED_OFF, b);
           	    //ioctl(fd_led1, LED_ON, b);
				break;
			case 2:
           	    //ioctl(fd_led2, LED_OFF, b);
				break;
			case 3:
           	    //ioctl(fd_led3, LED_OFF, b);
				break;
			}
        }
    }
    close(fd_led1);
//    close(fd_led2);
//    close(fd_led3);
    return 0;
}

驱动代码

#include <linux/init.h>
#include <linux/module.h>
#include<linux/fs.h>
#include<linux/device.h>
#include<linux/cdev.h>
#include<linux/slab.h>
#include<linux/io.h>
#include<linux/of.h>
#include<linux/of_gpio.h>
#include<linux/gpio.h>
#include<linux/timer.h>
#include<linux/of_irq.h>
#include<linux/interrupt.h>
#include "head.h"
struct cdev *cdev; 		//字符设备空间首地址
unsigned int major=500; //静态申请设备号
unsigned int minor=0;//次设备号的起始值
dev_t devno; 		//动态申请设备号
struct class *cls;  //接收注册结构体的地址
struct device *dev; //设备号

/*mykeys{
    interrupt-parent=<&gpiof>;
    interrupts=<9 0>,<7 0>,<8 0>;   //9表示引用中断父节点时的索引信息  0表示默认设置
};*/

//unsigned int irqno;//一个设备
int irqno;     //中断
struct gpio_desc *gpiono; 	//gpio
//struct gpio_desc *gpiono2;
//struct gpio_desc *gpiono3;
struct device_node *dnode;

char number = 0; 	  //定义number
char kbuf[128] = {0};  //驱动内的缓冲区

int mycdev_open(struct inode *inode, struct file *file)
{
//	unsigned int aaa = MINOR(inode->i_rdev);  	//得到次设备号aaa
//	file->private_data = (void *)aaa;

    printk("%s:%s:%d\n", __FILE__, __func__, __LINE__);
    return 0;
}

// 中断处理函数
irqreturn_t myirq_handler(int irqno, void *dev_id)
{
	printk("key1 interrupt\n");
	//灯状态取反
	gpiod_set_value(gpiono, !gpiod_get_value(gpiono));

	//将number的数据发送给kbuf缓冲区
	number = !number;

	/*
    unsigned int arg=(unsigned int)dev_id;
    switch(arg)
    {
        case 0:
            printk("key1 interrupt\n");
			//灯状态取反
			gpiod_set_value(gpiono, !gpiod_get_value(gpiono));

			//将number的数据发送给kbuf缓冲区
			number = !number;

            break;
        case 1:
            printk("key2 interrupt\n");
			//灯状态取反
            break;
        case 2:
            printk("key3 interrupt\n");
			//灯状态取反
            break;
    }*/
    return IRQ_HANDLED;
}

//应用程序回调的read
ssize_t mycdev_read(struct file *file, char *ubuf, size_t size, loff_t *lof)
{
    int ret;
    if(sizeof(kbuf)<size)
    size=sizeof(kbuf);
//    wait_event_interruptible(wq_head,condition);//将进程切换为休眠
//
	kbuf[0] = number;
	printk("**************************************%c\n",number);
    ret=copy_to_user(ubuf,kbuf,size);
    if(ret)
    {
        printk("copy_to_user filed\n");
        return -EIO;
    }

    printk("%s:%s:%d\n", __FILE__, __func__, __LINE__);
//    condition=0;//表示下一次硬件数据没有准备好
    return 0;
}

/*
long mycdev_ioctl(struct file *file, unsigned int cmd, unsigned long arg)
{

	myirq_handler(irqno, NULL);   //  按键1软中断
    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,
   // .unlocked_ioctl = mycdev_ioctl,
	.read = mycdev_read,
    .release = mycdev_close,
};

static int __init mycdev_init(void)   //寄存器地址映射和初始化
{
    int ret; 				//ret返回错误码 
	int ret1;
	
    //1.分配字符设备驱动对象空间  cdev_alloc
    cdev=cdev_alloc(); 		//字符设备空间首地址
    if(cdev==NULL)
    {
        printk("申请字符设备驱动对象空间失败\n");
        ret=-EFAULT;
        goto out1;
    }
    printk("字符设备驱动对象申请成功\n");

    //2.字符设备驱动对象部分初始化  cdev_init
    cdev_init(cdev,&fops);

    //3.申请设备号  register_chrdev_region/alloc_chrdev_region
    if(major>0)//静态申请设备号
    {
        ret=register_chrdev_region(MKDEV(major,minor),1,"led0"); //设备号需要是组合出来的,次设备数量，设备文件名
        if(ret)
        {
            printk("**********静态指定设备号失败**********\n");
            goto out2;
        }
    }
    else//动态申请设备号
    {
        ret=alloc_chrdev_region(&devno,minor,1,"led0");   //动态申请设备号，次设备号，设备数量，文件名
         if(ret)
        {
            printk("动态申请设备号失败\n");
            goto out2;
        }
        major=MAJOR(devno); 	//根据设备号得到主设备号
        minor=MINOR(devno); 	//根据设备号得到次设备号
    }
    printk("申请设备号成功\n");

    //4.注册字符设备驱动对象  cdev_add()
    ret=cdev_add(cdev,MKDEV(major,minor),1); //字符设备，设备号，设备数量
    if(ret)
    {
        printk("注册字符设备驱动对象失败\n");
        goto out3;
    }
    printk("注册字符设备驱动对象成功\n");

    //5.向上提交目录
    cls=class_create(THIS_MODULE,"led0"); //指向自身的指针，文件名
    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.向上提交设备节点
    dev=device_create(cls,NULL,MKDEV(major,0),NULL,"led0"); //创建设备节点
    if(IS_ERR(dev))
    {
        printk("向上提交节点信息失败\n");
        ret=-PTR_ERR(dev);
        goto out5;
    }
    printk("向上提交设备节点信息成功\n");

	//gpio子系统
    // 1、解析设备树节点
   dnode=of_find_node_by_name(NULL,"myleds");
   if(dnode==NULL)
   {
    printk("解析设备树节点失败\n");
    return -ENOMEM;
   }
   printk("解析设备树节点成功\n");
   // 2、根据设备树节点解析出gpio编号并申请对应的led
    gpiono=gpiod_get_from_of_node(dnode,"led1",0,GPIOD_OUT_LOW,NULL);
    if(IS_ERR(gpiono))
    {
        printk("解析设备号失败\n");
        return -PTR_ERR(gpiono);
    }
   printk("申请gpio编号成功\n");
   // 3、开灯
   gpiod_set_value(gpiono,1);


	//软中断
   //解析设备树节点

    dnode=of_find_node_by_name(NULL,"mykeys");
    if(dnode==NULL)
    {
        printk("解析设备树节点失败\n");
        return -ENXIO;
    }
    printk("设备树节点解析成功\n");
    
        // 获取软中断号
        irqno = irq_of_parse_and_map(dnode, 0);
        if (!irqno)
        {
            printk("软中断号获取失败\n");
            return -ENOMEM;
        }
        printk("软中断号获取成功irqno=%d\n", irqno);
        // 注册中断
 //       ret1 = request_irq(irqno, myirq_handler, IRQF_TRIGGER_FALLING, "key", (void *)1);
        ret1 = request_irq(irqno, myirq_handler, IRQF_TRIGGER_FALLING, "key", NULL);
        if (ret1)
        {
            printk("注册驱动失败\n");
            return ret1;
        }
        printk("key1中断注册成功\n");
  
    return 0;

out5:
    //销毁上面提交的设备信息
    device_destroy(cls,MKDEV(major,0));
    class_destroy(cls);
out4:
    cdev_del(cdev);
out3:
    unregister_chrdev_region(MKDEV(major,minor),1);
out2:
    kfree(cdev);
out1:
    return ret;

}
static void __exit mycdev_exit(void)
{
	//gpio子系统    
	// 4、灭灯
    gpiod_set_value(gpiono,0);
    // 5、释放gpio编号
    gpiod_put(gpiono);


    // 注销中断
    	free_irq(irqno,NULL);
    //1.销毁设备信息  device_destroy
    device_destroy(cls,MKDEV(major,0));
    //2.销毁目录  class_destroy
    class_destroy(cls);
    //3.注销对象  cdev_del()
    cdev_del(cdev);
    //4.释放设备号   unregister_chrdev_region()
    unregister_chrdev_region(MKDEV(major,minor),1);
    //5.释放对象空间  kfree()
    kfree(cdev);

	// 字符设备驱动的注销
    unregister_chrdev(major, "led0");
}
module_init(mycdev_init);
module_exit(mycdev_exit);
MODULE_LICENSE("GPL");