华清远见嵌入式学习——驱动开发——作业1

作业要求:

通过字符设备驱动分步注册过程实现LED驱动的编写,编写应用程序测试,发布到CSDN

作业答案:

运行效果:

驱动代码:

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

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

gpio_t *vir_led1;
gpio_t *vir_led2;
gpio_t *vir_led3;
unsigned int *vir_rcc;

// 封装操作方法
// 定义操作方法对象并初始化
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 wh;
    int ret=copy_from_user(&wh,(void *)arg,4);
    if(ret)//拷贝失败
    {
        printk("copy_from_user filed\n");
        return ret;
    }
    switch(cmd)
    {
        case LED_ON:
        switch(wh)
        {
            case 1:
             vir_led1->ODR |= (1<<10);
             break;
            case 2:
             vir_led2->ODR |= (1<<10);
             break;
            case 3:
             vir_led3->ODR |= (1<<8);
             break;
        } 
            break;
        case LED_OFF:
            switch(wh)
        {
            case 1:
              vir_led1->ODR &= (~(1<<10));
             break;
            case 2:
              vir_led2->ODR &= (~(1<<10));
             break;
            case 3:
              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;
}

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_led3->MODER |= (1<<16);
    vir_led3->ODR &= (~(1<<8));
    printk("寄存器初始化成功\n");
 
    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,
    .unlocked_ioctl=mycdev_ioctl,
    .release=mycdev_close,
};
static int __init mycdev_init(void)
{
    int ret;
    // 1.申请字符设备驱动对象空间
    cdev = cdev_alloc();
    if (cdev == NULL)
    {
        return -EFAULT;
    }
    printk("字符设备驱动对象申请成功\n");
    // 2.初始化字符设备驱动对象
    cdev_init(cdev, &fops);
    // 3.申请设备号
    if (major == 0) // 动态申请
    {
        ret = alloc_chrdev_region(&devno, minor, 3, "myled");
        if (ret)
        {
            printk("动态申请设备号失败\n");
            goto out1;
        }
        // 为了统一和静态申请设备号的操作
        major = MAJOR(devno);
        minor = MINOR(devno);
    }
    else // 静态指定
    {
        ret = register_chrdev_region(MKDEV(major, minor), 3, "myled");
        if (ret)
        {
            printk("静态申请设备号失败\n");
            goto out1;
        }
    }
    printk("设备号申请成功\n");
    // 4.注册驱动
    ret = cdev_add(cdev, MKDEV(major, minor), 3);
    if (ret)
    {
        printk("注册驱动失败\n");
        goto out2;
    }
    printk("注册驱动成功\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 out3;
    }
    printk("向上提交目录成功\n");
    // 6.向上提交设备节点
    int i;
    for (i = 0; i < 3; i++)
    {
        dev = device_create(cls, NULL, MKDEV(major, i), NULL, "myled%d", i);
        if (IS_ERR(dev))
        {
            printk("向上提交设备信息失败\n");
            ret = -PTR_ERR(dev);
            goto out4;
        }
    }
    printk("向上提交设备信息成功\n");

    // 寄存器映射以及初始化
    all_led_init();

    return 0;
out4:
    // 销毁提交成功的设备信息
    for (--i; i >= 0; i--)
    {
        device_destroy(cls, MKDEV(major, i));
    }
    // 销毁目录
    class_destroy(cls);
out3:
    cdev_del(cdev);
out2:
    unregister_chrdev_region(MKDEV(major, minor), 3);
out1:
    kfree(cdev);
    return ret;
}
static void __exit mycdev_exit(void)
{
    // 1.释放设备信息
    int i;
    for (i = 0; i < 3; i++)
    {
        device_destroy(cls, MKDEV(major, i));
    }
    // 2.销毁目录
    class_destroy(cls);
    // 3.注销驱动对象
    cdev_del(cdev);
    // 4.释放设备号
    unregister_chrdev_region(MKDEV(major, minor), 3);
    // 5.释放对象空间
    kfree(cdev);
}
module_init(mycdev_init);
module_exit(mycdev_exit);
MODULE_LICENSE("GPL");

应用程序:

#include
#include
#include 
#include 
#include 
#include
#include
#include
#include"head.h"
 
 
int main(int argc, char const *argv[])
{
    int a,b;
    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("请输入要实现的功能\n");
        printf("0(关灯) 1(开灯)\n");
        printf("请输入>");
        scanf("%d",&a);
        printf("请输入要控制的灯\n");
        printf("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;
}

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
 
//构建功能码
#define LED_ON _IOW('l',1,int)  
#define LED_OFF _IOW('l',0,int)
#endif 

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