驱动DAY4 字符设备驱动分步注册和ioctl函数点亮LED灯

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)//开灯
#define LED_OFF _IOW('l',0,int)//关灯

#endif 

驱动代码

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

struct cdev *cdev;
unsigned int major = 0;
unsigned int minor = 0;
dev_t devno;
struct class *cls;
struct device *dev;

char kbuf[128] = {0};
gpio_t *vir_led1;
gpio_t *vir_led2;
gpio_t *vir_led3;
unsigned int *vir_rcc;

// 封装操作方法
int mycdev_open(struct inode *inode, struct file *file)
{
    printk("%s:%s:%d\n", __FILE__, __func__, __LINE__);
    return 0;
}

long mycdev_ioctl(struct file *file, unsigned int cmd, unsigned long arg)
{
    // 根据用户空间功能码的不同实现硬件不同的控制
    switch (cmd)
    {
    case LED_ON: // 开灯
        switch (arg)
        {
        case 1:
            vir_led1->ODR |= (0X1 << 10);
            break;
        case 2:
            vir_led2->ODR |= (0X1 << 10);
            break;
        case 3:
            vir_led3->ODR |= (0X1 << 8);
            break;
        default:
            printk("灯选择输入错误\n");
            break;
        }
        break;
    case LED_OFF: // 关灯
        switch (arg)
        {
        case 1:
            vir_led1->ODR &= (~(0X1 << 10));
            break;
        case 2:
            vir_led2->ODR &= (~(0X1 << 10));
            break;
        case 3:
            vir_led3->ODR &= (~(0X1 << 8));
            break;
        default:
            printk("灯选择输入错误\n");
            break;
        }
        break;
    default:
        printk("开关灯选择输入错误\n");
        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遍历并且初始化
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)
{
    int ret;
    // 1.分配字符设备驱动对象
    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("申请字符设备驱动成功\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) // 静态指定
    {
        ret = register_chrdev_region(MKDEV(major, minor), 3, "mycdev");
        if (ret)
        {
            printk("静态指定设备号失败\n");
            goto OUT2;
        }
    }
    else
    {
        ret = alloc_chrdev_region(&devno, minor, 3, "mycdev");
        if (ret)
        {
            printk("静态指定设备号失败\n");
            goto OUT2;
        }
        minor = MINOR(devno); // 根据设备号获取次设备号
        major = MAJOR(devno); // 根据设备号获取主设备号
    }
    printk("申请设备号成功\n");
    // 4.注册字符设备驱动对象
    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");
    // 向上提交目录
    cls = class_create(THIS_MODULE, "mycdev");
    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");
    // 向上提交设备节点信息
    int i=0;
    for (i = 0; i < 3; i++)
    {
        dev = device_create(cls, NULL, MKDEV(major, i), NULL, "mycdev%d", i);
        if (IS_ERR(dev))
        {
            printk("向上提交设备节点信息失败\n");
            ret = -PTR_ERR(dev);
            goto OUT5;
        }
    }
    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;
OUT5:
    for (--i; i >= 0; i--)
    {
        device_destroy(cls, MKDEV(major, i)); // 释放提交成功的设备信息
    }
    class_destroy(cls); // 销毁目录
OUT4:
    cdev_del(cdev);
OUT3:
    unregister_chrdev_region(MKDEV(major, minor), 3);
OUT2:
    kfree(cdev);
OUT1:
    return ret;
}
static void __exit mycdev_exit(void)
{
    // 销毁设备节点信息
    int i;
    for (i = 0; i < 3; i++)
    {
        device_destroy(cls, MKDEV(major, i));
    }
    // 销毁目录
    class_destroy(cls);
    // 注销字符设备驱动对象
    cdev_del(cdev);
    // 释放设备号
    unregister_chrdev_region(MKDEV(major, minor), 3);
    // 释放对象空间
    kfree(cdev);
}
module_init(mycdev_init);
module_exit(mycdev_exit);
MODULE_LICENSE("GPL");

测试代码

#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/mycdev0", O_RDWR);
    if (fd < 0)
    {
        printf("打开设备文件失败\n");
        exit(-1);
    }
    while (1)
    {
        printf("请输入要实现的功能：1（开灯）0（关灯>）");
        scanf("%d", &a);
        printf("请输入要控制的灯：1（LED1） 2(LED2) 3(LED3)>");
        scanf("%d", &b);
        switch (a)
        {
        case 1:
            ioctl(fd, LED_ON, b);
            break;
        case 0:
            ioctl(fd, LED_OFF, b);
            break;
        default:
            printf("开关灯功能选择输入错误\n");
            break;
        }
    }

    close(fd);

    return 0;
}

Makefile

#通用makefile
modname ?= demo
arch ?= arm
ifeq ($(arch),arm)
KERNELDIR:= /home/ubuntu/FSMP1A/linux-stm32mp-5.10.61-stm32mp-r2-r0/linux-5.10.61
#生成ARM架构
else
KERNELDIR:= /lib/modules/$(shell uname -r)/build
#生成x86架构
endif

PWD:= $(shell pwd)
all:
	make -C $(KERNELDIR) M=$(PWD) modules

clean:
	make -C $(KERNELDIR) M=$(PWD) clean

obj-m:= $(modname).o

实验现象