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 <linux/init.h>
#include <linux/module.h>
#include <linux/fs.h>
#include <linux/cdev.h>
#include <linux/device.h>
#include "head.h"
#include <linux/slab.h>
#include <linux/io.h>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);// led1vir_led1->MODER &= (~(3 << 20));vir_led1->MODER |= (1 << 20);vir_led1->ODR &= (~(1 << 10));// led2vir_led2->MODER &= (~(3 << 20));vir_led2->MODER |= (1 << 20);vir_led2->ODR &= (~(1 << 10));// led3vir_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 <stdlib.h>
#include <stdio.h>
#include <sys/types.h>
#include <sys/stat.h>
#include <fcntl.h>
#include <unistd.h>
#include <string.h>
#include <sys/ioctl.h>
#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
endifPWD:= $(shell pwd)
all:make -C $(KERNELDIR) M=$(PWD) modulesclean:make -C $(KERNELDIR) M=$(PWD) cleanobj-m:= $(modname).o

实验现象