驱动开发，stm32mp157a开发板的led灯控制实验(优化)，使用ioctl函数，让write/read函数的专注读写功能

 1.实验目的

        编写LED灯的驱动，在应用程序中编写控制LED灯亮灭的代码逻辑实现LED灯功能的控制；

 

 2.LED灯相关寄存器分析

LED1->PE10 LED1亮灭：

RCC寄存器[4]->1 0X50000A28

GPIOE_MODER[21:20]->01 (输出) 0X50006000

GPIOE_ODR[10]->1(输出高电平) 0（输出低电平）0X50006014

LED2->PF10 LED2亮灭：

RCC寄存器[5]->1 0X50000A28

GPIOE_MODER[21:20]->01 (输出) 0X50006000

GPIOE_ODR[10]->1(输出高电平) 0（输出低电平）0X50006014

LED3->PE8 LED3亮灭：

RCC寄存器[4]->1 0X50000A28

GPIOE_MODER[17:16]->01 (输出) 0X50006000

GPIOE_ODR[8]->1(输出高电平) 0（输出低电平）0X50006014

GPIOE_OTYPER默认为00

GPIOE_PUPDR默认为0

GPIOE_OSPEEDR默认为00

 

3.编写代码

---Makefile---工程管理文件

modname?=demo
arch?=arm
ifeq ($(arch),arm)
KERNELDIR:= /home/ubuntu/FSMP1A/linux-stm32mp-5.10.61-stm32mp-r2-r0/linux-5.10.61 #编译生成ARM架构
else
KERNELDIR:=/lib/modules/$(shell uname -r)/build #编译生成X86架构
endif

PWD:=$(shell pwd) #模块化编译文件路径
all:
	make -C $(KERNELDIR) M=$(PWD) modules
clean:
	make -C $(KERNELDIR) M=$(PWD) clean

obj-m:=$(modname).o

---head.h---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;

//LED1和LED3寄存器地址
#define LED1_ADDR 0x50006000
#define LED2_ADDR 0x50007000
#define LED3_ADDR 0x50006000
#define RCC_ADDR 0x50000A28

//构建LED开关功能码,添加ioctl第三个参数int
#define LED_ON _IOW('l',1,int)
#define LED_OFF _IOW('l',0,int)


#endif

---led_drive.c---驱动程序

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

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

struct class *cls;
struct device *dev;

// 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)
{
    int value;
    //获取arg对应用户空间中的值
    int ret = copy_from_user(&value,(void*)arg,4);
    if(ret)
    {
        printk("从用户空间获取数据失败\n");
        return -EIO;
    }

    switch (cmd)
    {
    case LED_ON: // 开灯
        switch (value)
        {
        case 1: // LED1
            vir_led1->ODR |= (0x1 << 10);
            break;
        case 2:
            vir_led2->ODR |= (0x1 << 10);
            break;
        case 3:
            vir_led3->ODR |= (0x1 << 8);
            break;
        }
        break;

    case LED_OFF: // 关灯
        switch (value)
        {
        case 1: // LED1
            vir_led1->ODR &= (~(0x1 << 10));
            break;
        case 2:
            vir_led2->ODR &= (~(0x1 << 10));
            break;
        case 3:
            vir_led3->ODR &= (~(0x1 << 8));
            break;
        }
        break;
    }
    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,
};

// 相关寄存器地址映射及初始化
int all_led_init(void)
{
    // 相关寄存器的内存映射
    vir_led1 = ioremap(LED1_ADDR, sizeof(gpio_t));
    if (vir_led1 == NULL)
    {
        printk("物理内存映射失败%d\n", __LINE__);
        return -ENOMEM;
    }

    vir_led2 = ioremap(LED2_ADDR, sizeof(gpio_t));
    if (vir_led2 == NULL)
    {
        printk("物理内存映射失败%d\n", __LINE__);
        return -ENOMEM;
    }

    vir_led3 = vir_led1;

    vir_rcc = ioremap(RCC_ADDR, 4);
    if (vir_rcc == NULL)
    {
        printk("物理内存映射失败%d\n", __LINE__);
        return -ENOMEM;
    }
    printk("寄存器内存映射成功\n");

    // 硬件寄存器的初始化
    (*vir_rcc) |= (0x3 << 4);

    // LED1
    vir_led1->MODER &= (~(0x3 << 20));
    vir_led1->MODER |= (0x1 << 20);
    vir_led1->ODR &= (~(0x1 << 10));

    // LED2
    vir_led2->MODER &= (~(0x3 << 20));
    vir_led2->MODER |= (0x1 << 20);
    vir_led2->ODR &= (~(0x1 << 10));

    // LED3
    vir_led3->MODER &= (~(0x3 << 16));
    vir_led3->MODER |= (0x1 << 16);
    vir_led3->ODR &= (~(0x1 << 8));

    printk("寄存器初始化成功\n");
    return 0;
}

// 入口函数
static int __init mycdev_init(void)
{
    major = register_chrdev(0, "mychrdev", &fops);
    if (major < 0)
    {
        printk("字符设备驱动注册失败\n");
        return major;
    }
    printk("字符设备驱动注册成功:major=%d\n", major);

    // 寄存器映射及初始化
    all_led_init();

    // 向上提交目录
    cls = class_create(THIS_MODULE, "mychrdev");
    if (IS_ERR(cls))
    {
        printk("向上提交目录失败\n");
        return -PTR_ERR(cls);
    }
    printk("向上提交目录成功\n");

    // 向上提交设备节点信息
    int i;
    for (i = 0; i < 3; i++)
    {
        dev = device_create(cls, NULL, MKDEV(major, i), NULL, "mychrdev%d", i);
        if (IS_ERR(dev))
        {
            printk("向上提交设备节点信息失败\n");
            return -PTR_ERR(dev);
        }
    }
    printk("向上提交设备节点信息成功\n");

    return 0;
}

// 出口函数
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));
    }

    // 销毁目录信息
    class_destroy(cls);

    // 取消物理内存的映射
    iounmap(vir_led1);
    iounmap(vir_led2);
    iounmap(vir_rcc);

    // 字符设备驱动注销
    unregister_chrdev(major, "mychrdev");
}

// 声明
// 入口函数地址
module_init(mycdev_init);
// 出口函数地址
module_exit(mycdev_exit);
// 遵循的GPL协议
MODULE_LICENSE("GPL");

---test.c---应用程序测试程序

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

int main(int argc, char const *argv[])
{
    int a,b;
    char buf[128] = {0};
    int fd = open("/dev/mychrdev0", O_RDWR);

    if (fd < 0)
    {
        printf("设备文件打开失败\n");
        exit(-1);
    }
    while (1)
    {
        printf("请输入对LED灯的控制：1(开灯) 0(关灯)>> ");
        scanf("%d",&a);
        //getchar();
        printf("请输入要控制的灯：1(LED1) 2(LED2) 3(LED3)>> ");
        scanf("%d",&b);
        //getchar();
        
        switch(a)
        {
            case 1:
                ioctl(fd,LED_ON,&b);  //第三个参数为指针
                break;
            case 0:
                ioctl(fd,LED_OFF,&b);
                break;
        }
    }

    close(fd);

    return 0;
}

4.测试现象