驱动开发，stm32mp157a开发板的led灯控制实验(再优化)，使用ioctl函数，通过字符设备驱动分步注册方式编写LED驱动，完成设备文件和设备的绑定

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.字符设备驱动内部注册过程

分配struct cdev对象空间
初始化struct cdev对象
设备号的申请（静态/动态申请）
注册cdev对象

4.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
endifPWD:=$(shell pwd) #模块化编译文件路径
all:make -C $(KERNELDIR) M=$(PWD) modules
clean:make -C $(KERNELDIR) M=$(PWD) cleanobj-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,不添加ioctl第三个参数
#define LED_ON _IO('l',1)
#define LED_OFF _IO('l',0)#endif

---cdev.c---驱动程序

#include <linux/init.h>
#include <linux/module.h>
#include <linux/cdev.h>
#include <linux/fs.h>
#include <linux/device.h>
#include <linux/uaccess.h>
#include <linux/slab.h>
#include "head.h"
#include <linux/io.h>struct cdev *cdev = NULL;
unsigned major = 0;
unsigned minor = 0;
module_param(major, uint, 0664); // 方便再命令行传递major的值
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)
{// 设备文件和设备的绑定// 根据打开的文件对应的设备号获取 次设备号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: // 控制LED1switch (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 2: // 控制LED2switch (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 3: // 控制LED3switch (cmd){case LED_ON: // 开灯vir_led3->ODR |= (0x1 << 8);break;case LED_OFF: // 关灯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);// LED1vir_led1->MODER &= (~(0x3 << 20));vir_led1->MODER |= (0x1 << 20);vir_led1->ODR &= (~(0x1 << 10));// LED2vir_led2->MODER &= (~(0x3 << 20));vir_led2->MODER |= (0x1 << 20);vir_led2->ODR &= (~(0x1 << 10));// LED3vir_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;
}static int __init mycdev_init(void)
{int ret;// 分配字符设备驱动对象空间cdev = cdev_alloc();if (cdev == NULL){printk("字符设备驱动对象申请空间失败\n");ret = -EFAULT;goto out1;}printk("字符设备驱动对象申请空间成功\n");// 字符设备驱动对象初始化cdev_init(cdev, &fops);// 设备号的申请if (major > 0) // 静态指定设备号{ret = register_chrdev_region(MKDEV(major, minor), 3, "myled");if (ret){printk("静态申请设备号失败\n");goto out2;}}else if (major == 0) 动态申请设备号{ret = alloc_chrdev_region(&devno, minor, 3, "myled");if (ret){printk("静态申请设备号失败\n");goto out2;}major = MAJOR(devno);minor = MINOR(devno);}printk("申请设备号成功\n");// 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");相关寄存器地址映射及初始化all_led_init();// 向上提交目录信息cls = class_create(THIS_MODULE, "myled");if (IS_ERR(cls)){printk("向上提交目录信息失败\n");ret = -PTR_ERR(cls);goto out4;}printk("向上提交目录信息成功\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, "myled%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("向上提交设备节点信息成功\n");return 0;
out5:// 释放前一次提交的设备信息for (--i; i >= 0; i--){device_destroy(cls, MKDEV(major, i));}class_destroy(cls); // 释放目录信息
out4:cdev_del(cdev);
out3:unregister_chrdev_region(MKDEV(major, minor), 3);
out2:kfree(cdev);
out1:return ret;
}static void __exit mycdev_exit(void)
{// 释放节点信息int i;for (i = 0; i < 3; i++){device_destroy(cls, MKDEV(major, i));}// 销毁目录class_destroy(cls);// 注销驱动对象cdev_del(cdev);// 释放申请的设备号和设备资源unregister_chrdev_region(MKDEV(major, minor), 3);// 释放字符设备驱动对象空间kfree(cdev);// 取消物理内存的映射iounmap(vir_led1);iounmap(vir_led2);iounmap(vir_rcc);
}
module_init(mycdev_init);
module_exit(mycdev_exit);
MODULE_LICENSE("GPL");

---test.c---应用程序测试程序

#include <stdio.h>
#include <sys/types.h>
#include <sys/stat.h>
#include <fcntl.h>
#include <unistd.h>
#include <stdlib.h>
#include <string.h>
#include "head.h"
#include <sys/ioctl.h>int main(int argc, char const *argv[])
{int a;char buf[128] = {0};int fd = open("/dev/myled0", 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();switch (a){case 1:ioctl(fd, LED_ON); // 第三个参数为指针break;case 0:ioctl(fd, LED_OFF);break;}}close(fd);return 0;
}