驱动开发 字符设备驱动分部注册实现LED灯

head.h

#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 

驱动文件

#include 
#include 
#include 
#include 
#include 
#include 
#include 
#include 
#include 
#include"head.h"

unsigned int major=0;//主设备号
unsigned int minor=0;//次设备号
dev_t devno;
struct cdev *cdev;
gpio_t *vir_led1;
gpio_t *vir_led2;
gpio_t *vir_led3;
unsigned int *vir_rcc;
char kbuf[128]={0};
struct class *cls;
struct device *dev;

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;
    }
    return 0;
}
long mycdev_ioctl (struct file *file, unsigned int cmd, unsigned long arg)
{
    int ar;
    int ret;
    ret=copy_from_user(&ar,(void*)arg,4);
    if(ret)//拷贝失败
    {
        printk("copy_to_user filed\n");
        return ret;
    }
    switch(cmd)
    {
        case LED_ON:
        switch(ar)
        {
            case 0:
            vir_led1->ODR |= 1<<10;
            break;
            case 1:
            vir_led2->ODR |= 1<<10;
            break;
            case 2:
            vir_led3->ODR |= 1<<8;
            break;
        }
        break;
        case LED_OFF:
        switch(ar)
        {
            case 0:
            vir_led1->ODR &= (~(1<<10));
            break;
            case 1:
            vir_led2->ODR &= (~(1<<10));
            break;
            case 2:
            vir_led3->ODR &= (~(1<<8));
            break;
        }
        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={
    .unlocked_ioctl=mycdev_ioctl,
    .open=mycdev_open,
    .read=mycdev_read,
    .write=mycdev_write,
    .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)
{
    int ret;
    //1.创建驱动对象
    cdev=cdev_alloc();
    if(cdev==NULL)
    {
        return -ENOMEM;
    }
    printk("驱动对象创建成功\n");
    //2.驱动对象初始化
    cdev_init(cdev, &fops);
    //3.申请设备号
    ret=alloc_chrdev_region(&devno, 0 ,3,"myled");
    if(ret)
    {
        printk("设备号申请失败\n");
        goto out;
    }
    major=MAJOR(devno);
    minor=MINOR(devno);
    printk("设备号申请成功\n");
    //4.驱动注册
    ret=cdev_add(cdev,devno,3);
    if(ret)
    {
        printk("驱动注册失败\n");
        goto out1;
    }
    printk("驱动注册成功\n");
    //5.向上提交目录
    cls=class_create(THIS_MODULE,"led");
    if(IS_ERR(cls))
    {
        printk("向上提交目录失败\n");
        ret=-PTR_ERR(cls);
        goto out2;
    }
    printk("向上提交目录成功\n");
    //6.向上提交节点
    int i;
    //向上提交三次设备节点信息
    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 out3;
        }
    }
    printk("向上提交设备节点成功\n");
    
    //寄存器映射以及初始化
    all_led_init();
    return 0;
out3:
    for(--i;i>=0;i--)
    {
        device_destroy(cls,MKDEV(major,i));
    }
    class_destroy(cls);
out2:
    cdev_del(cdev);
out1:
    unregister_chrdev_region(devno,3);
out:
    kfree(cdev);
    return ret;
}
static void __exit mycdev_exit(void)
{
    //取消地址映射
    iounmap(vir_led1);
    iounmap(vir_led2);
    iounmap(vir_rcc);
    //销毁节点
    int i;
    for(i=0;i<3;i++)
    {
        device_destroy(cls,MKDEV(major,i));
    }
    //销毁目录
    class_destroy(cls);
    //销毁驱动对象
    cdev_del(cdev);
    //销毁驱动号
    unregister_chrdev_region(MKDEV(major,minor), 3);
    //释放驱动对象
    kfree(cdev);
}
module_init(mycdev_init);
module_exit(mycdev_exit);
MODULE_LICENSE("GPL");

应用文件

#include
#include
#include 
#include 
#include 
#include
#include
#include 
#include "head.h"

int main(int argc, char const *argv[])
{
    int a,b;
    char buf[128]={0};
    int fd=open("/dev/myled0",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("请输入功能选择\n");
        printf("0(关灯) 1(开灯)\n");
        printf("请输入>");
        scanf("%d",&a);
        printf("请输入灯选择\n");
        printf("0(led0) 1(led1) 2(led2)\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;
}

现象实现