驱动代码：

#include <linux/init.h>
#include <linux/module.h>
#include <linux/fs.h>
#include <linux/io.h>
#include <linux/device.h>
#include <linux/uaccess.h>
#include <linux/slab.h>
#include <linux/cdev.h>
#include "head.h"gpio_t *vir_led1;
gpio_t *vir_led2;
gpio_t *vir_led3;unsigned int *vir_rcc;struct cdev *cdev;
struct class *cls;
struct device *dev;unsigned int major = 500;
unsigned int minor = 0; //此设备的起始值
dev_t devno;
char kbuf[128] = {0};
// 封装操作方法int mycdev_open(struct inode *inode, struct file *file)
{int a = inode->i_rdev;                 //获取当前设备文件对应的设备号file->private_data = (void *)MINOR(a); //将次设备号保存到当前文件的file结构中printk("%s:%s:%d\n", __FILE__, __func__, __LINE__);return 0;
}long mycdev_ioctl(struct file *file, unsigned int cmd, unsigned long arg)
{unsigned int a = (unsigned int)file->private_data;switch (a){case 0:switch (cmd){case LED_ON:vir_led1->ODR |= (0x1 << 10); // 开灯break;case LED_OFF:vir_led1->ODR &= (~(0x1 << 10));break;}break;case 1:switch (cmd){case LED_ON:vir_led2->ODR |= (0x1 << 10); // 开灯break;case LED_OFF:vir_led2->ODR &= (~(0x1 << 10));break;}break;case 2:switch (cmd){case LED_ON:vir_led3->ODR |= (0x1 << 8); // 开灯break;case LED_OFF:vir_led3->ODR &= (~(0x1 << 8));break;}break;}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__);if (size > sizeof(kbuf)) //用户的需求内核满足不了{size = sizeof(kbuf);}long ret;ret = copy_to_user(ubuf, kbuf, size);if (ret){printk("copy_to_user filed\n");return -EIO;}return 0;
}ssize_t mycdev_write(struct file *file, const char *ubuf, size_t size, loff_t *lof)
{printk("%s:%s:%d\n", __FILE__, __func__, __LINE__);if (size > sizeof(kbuf)) //用户的需求内核满足不了{size = sizeof(kbuf);}long ret;ret = copy_from_user(kbuf, ubuf, size);if (ret){printk("copy_from_user filed\n");return -EIO;}return 0;
}int mycdev_close(struct inode *inode, struct file *file)
{printk("%s:%s:%d\n", __FILE__, __func__, __LINE__);return 0;
}//定义一个操作方法结构体变量并且初始化
struct file_operations fops = {.open = mycdev_open,.read = mycdev_read,.write = mycdev_write,.release = mycdev_close,.unlocked_ioctl = mycdev_ioctl,
};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_led3->MODER |= (1 << 16);vir_led3->ODR &= (~(1 << 8));printk("寄存器初始化成功\n");return 0;
}static int __init mycdev_init(void)
{int ret;// 1.申请对象空间 cdev_alloccdev = cdev_alloc();if (cdev == NULL){printk("申请对象空间失败\n");ret = -EFAULT;goto OUT1;}// 2.初始化对象  cdev_initcdev_init(cdev, &fops);// 3.s申请设备号  register_chrdev_region()/alloc_chrdev_region()if (major == 0){//动态申请ret = alloc_chrdev_region(&devno, minor, 3, "mycdev");if (ret){printk("动态申请设备号失败\n");goto OUT2;}//统一后面的操作major = MAJOR(devno); //根据设备号获取主设备号minor = MINOR(devno); //根据设备号获取次设备号}else{//静态申请ret = register_chrdev_region(MKDEV(major, minor), 3, "mycdev");if (ret){printk("静态指定设备号失败\n");goto OUT2;}}printk("设备号申请成功\n");// 4.注册驱动对象 cdev_add()ret = cdev_add(cdev, MKDEV(major, minor), 3);if (ret){printk("注册设备驱动对象失败\n");goto OUT3;}// 5.向上提交目录  class_create()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;}// 6.向上提交设备信息 device_create()int i;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));}class_destroy(cls);
OUT4:cdev_del(cdev);
OUT3:unregister_chrdev_region(MKDEV(major, minor), 3);
OUT2:kfree(cdev);
OUT1:return ret;
}static void __exit mycdev_exit(void)
{// 取消地址映射iounmap(vir_led1);iounmap(vir_led2);iounmap(vir_rcc);// 1.销毁设备信息  device_destroyint i;for (i = 0; i < 3; i++){device_destroy(cls, MKDEV(major, i));}// 2.销毁目录    class_destroyclass_destroy(cls);// 3.注销驱动对象  cdev_delcdev_del(cdev);// 4.释放设备号   unregister_chrdev_region()unregister_chrdev_region(MKDEV(major, minor), 3);// 5.释放对象空间   kfree()kfree(cdev);
}
module_init(mycdev_init);
module_exit(mycdev_exit);
MODULE_LICENSE("GPL");

应用层代码：

#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[])
{int a, b, fd0, fd1, fd2;while (1){printf("请输入要控制的灯 1(LED1) 2(LED2) 3(LED3):");scanf("%d", &b);fd0 = open("/dev/mycdev0", O_RDWR);if (fd0 < 0){printf("打开设备文件失败\n");exit(-1);}fd1 = open("/dev/mycdev1", O_RDWR);if (fd1 < 0){printf("打开设备文件失败\n");exit(-1);}fd2 = open("/dev/mycdev2", O_RDWR);if (fd2 < 0){printf("打开设备文件失败\n");exit(-1);}printf("请输入指令\n");printf("0(关灯) 1(开灯)\n");printf("请输入:");scanf("%d", &a);switch (a){case 1:switch (b){case 1:ioctl(fd0, LED_ON); //开灯break;case 2:ioctl(fd1, LED_ON);break;case 3:ioctl(fd2, LED_ON);break;}break;case 0:switch (b){case 1:ioctl(fd0, LED_OFF); //关灯break;case 2:ioctl(fd1, LED_OFF);break;case 3:ioctl(fd2, LED_OFF);break;}break;}}close(fd0);close(fd1);close(fd2);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//功能码
#define LED_ON _IOW('l', 1, int)
#define LED_OFF _IOW('l', 0, int)#endif