驱动开发LED灯绑定设备文件

头文件

#ifndef __HEAD_H__
#define __HEAD_H__

typedef struct 
{
    unsigned int MODER;
    unsigned int OTYPER;
    unsigned int OSPEEDR;
    unsigned int PUPDR;
    unsigned int IDR;
    unsigned int ODR;
}gpio_t;


#define PHY_LED1_ADDR 0x50006000
#define PHY_LED2_ADDR 0x50007000
#define PHY_LED3_ADDR 0x50006000
#define PHY_RCC_ADDR 0x50000A28
#define LED_ON _IOW('l',1,int)
#define LED_OFF _IOW('l',0,int)

#endif

应用程序

#include 
#include 
#include 
#include 
#include 
#include 
#include 
#include 
#include "head.h"
int main(int argc,char const *argv[])
{
    char buf[128]={0};
    int a,b;
    int fd=open("/dev/demo0",O_RDWR);
    if(fd<0)
    {
        printf("打开设备文件失败\n");
        exit(-1);
    }
    while(1)
    {
        //从终端读取
        printf("请输入要实现的功能 ");
        printf("0(关灯) 1(开灯)\n");
        printf("请输入>");
        scanf("%d",&a);
        printf("请选择要控制的灯：1（LED1）2(LED2) 3(LED3)\n");
        printf("请输入>");
        scanf("%d",&b);
        switch(a)
        {
            case 1:
                ioctl(fd,LED_ON,&b);
                break;
            case 0:
                ioctl(fd,LED_OFF,&b);
                break;
        }
    }

    
    close(fd);

    return 0;
}

驱动程序

#include 
#include 
#include 
#include 
#include 
#include 
#include 
#include 
#include "head.h"
unsigned int major=0;
unsigned int minor=0;
char kbuf[128]={};
gpio_t *vir_led1;
gpio_t *vir_led2;
gpio_t *vir_led3;
unsigned int *vir_rcc;
struct cdev *cdev;
dev_t devno;
struct class *cls;
struct device *dev;

int mycdev_open(struct inode *inode, struct file *file)
{
    int min=MINOR(inode->i_rdev);
    file->private_data=(void *)min;
    printk("%s:%s:%d\n",__FILE__,__func__,__LINE__);
    return 0;
}

long mycdev_ioctl(struct file *file,unsigned int cmd,unsigned long arg)
{
    int min=(int)file->private_data;
    switch (min)
    {
    case 0: // 操作LED1
        switch (cmd)
        {
        case LED_ON: //开灯
            vir_led1->ODR |= (0x1<<10);
            break;
        case LED_OFF://关灯
            vir_led1->ODR &= (~(0x1<<10));
            break;
        }
        break;
    case 1: // 操作LED2
        switch (cmd)
        {
        case LED_ON: //开灯
            vir_led2->ODR |= (0x1<<10);
            break;
        case LED_OFF://关灯
            vir_led2->ODR &= (~(0x1<<10));
            break;
        }
        break;
    case 2: // 操作LED3
        switch (cmd)
        {
        case LED_ON: //开灯
            vir_led3->ODR |= (0x1<<8);
            break;
        case LED_OFF://关灯
            vir_led3->ODR &= (~(0x1<<8));
            break;
        }
        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;
}

struct file_operations fops =
{
    .open=mycdev_open,
    .unlocked_ioctl=mycdev_ioctl,
    .release=mycdev_close,
};

int all_led_init(void)
{
    //寄存器地址的映射
    vir_led1=ioremap(PHY_LED1_ADDR,sizeof(gpio_t));
    if(vir_led1==NULL)
    {
        printk("ioremap filed：%d\n",__LINE__);
        return -ENOMEM;
    }
     vir_led2=ioremap(PHY_LED2_ADDR,sizeof(gpio_t));
    if(vir_led2==NULL)
    {
        printk("ioremap filed：%d\n",__LINE__);
        return -ENOMEM;
    }
     vir_led3=vir_led1;
    vir_rcc=ioremap(PHY_RCC_ADDR,4);
    if(vir_rcc==NULL)
    {
        printk("ioremap filed：%d\n",__LINE__);
        return -ENOMEM;
    }
    printk("物理地址映射成功\n");
    //寄存器的初始化
    //rcc
    (*vir_rcc) |= (3<<4);
    //led1
    vir_led1->MODER &= (~(3<<20));
    vir_led1->MODER |= (1<<20);
    vir_led1->ODR &= (~(1<<10));
    //led2
    vir_led2->MODER &= (~(3<<20));
    vir_led2->MODER |= (1<<20);
    vir_led2->ODR &= (~(1<<10));
    //led3
    vir_led3->MODER &= (~(3<<16));
    vir_led1->MODER |= (1<<16);
    vir_led1->ODR &= (~(1<<8));
    printk("寄存器初始化成功\n");

    return 0;
}

static int __init mycdev_init(void)
{
        //1.申请一个对象空间cdev_alloc
    int ret;
    cdev= cdev_alloc();
    if(cdev==NULL)
    {
        printk("申请字符设备驱动对象失败\n");
        ret=-EFAULT;
        goto out1;

    }
    printk("字符设备驱动对象申请成功\n");
    //2.初始化对象cdev_init
    cdev_init(cdev,&fops);
    //3.申请设备号  register_chrdev_region()/alloc_chrdev_region()
    if(major==0)//动态申请
    {
        ret=alloc_chrdev_region(&devno,minor,3,"demo");
        if(ret)
        {
            printk("动态申请设备号失败\n");
            goto out2;
        }
        major=MAJOR(devno);//根据设备号获取主设备号
        minor=MINOR(devno);//根据设备号获取次设备号
    }
    else
    {
        ret=register_chrdev_region(MKDEV(major,minor),3,"demo");
        if(ret)
        {
            printk("静态指定设备号失败\n");
            goto out2;
        }
    }
    printk("设备号申请成功\n");
    //4.注册驱动对象  cdev_add
    ret=cdev_add(cdev,MKDEV(major,minor),3);
    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  class_create
    cls=class_create(THIS_MODULE,"demo");
    if(IS_ERR(cls))
    {
        printk("向上提交目录失败\n");
        goto out4;
    }
    printk("向上提交目录成功\n");
    //6.向上提交设备节点信息  device_create
    int i;
    for(i=0;i<3;i++)
    {
        dev=device_create(cls,NULL,MKDEV(major,i),NULL,"demo%d",i);
        if(IS_ERR(dev))
        {
            printk("向上提交设备节点失败\n");
            goto out5;
        }
    }
    printk("向上提交设备节点信息成功\n");
    
    all_led_init();
    return 0;
out5:
//将提交成功的节点信息释放
    for(--i;i>=0;i--)
    {
        device_destroy(cls,MKDEV(major,i));
    }
    //销毁目录
    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)
{
    iounmap(vir_led1);
    iounmap(vir_led2);
    iounmap(vir_rcc);

//1.销毁设备节点信息
    int i;
    for(i=0;i<3;i++)
    {
        device_destroy(cls,MKDEV(major,i));
    }
    //2.销毁目录
    class_destroy(cls);
    //3.注销字符设备驱动对象
    cdev_del(cdev);
    //4.释放设备号
    unregister_chrdev_region(MKDEV(major,minor),3);
    //5.释放申请到的字符设备驱动对象空间
    kfree(cdev);
}

module_init(mycdev_init);
module_exit(mycdev_exit);
MODULE_LICENSE("GPL");