编写驱动代码实现LED灯点亮

代码实现LED灯点亮"/>

编写驱动代码实现LED灯点亮

一、head.h

#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_RCC_ADDR  0X50000A28
#define PHY_LED1_ADDR 0X50006000
#define PHY_LED2_ADDR 0X50007000
#define PHY_LED3_ADDR 0X50006000#endif

二、test.c

#include <stdio.h>
#include <sys/types.h>
#include <sys/stat.h>
#include <fcntl.h>
#include <unistd.h>
#include <string.h>int main(int argc, const char *argv[])
{char buf[128] = {0};int fd = open("/dev/mychrdev", O_RDWR);if (fd < 0){printf("打开设备文件失败\n");return -1;}printf("打开字符设备文件成功\n");while (1){printf("请输入需要控制的LED灯[1(LED1) 2(LED2) 3(LED3)]以及状态[0(关灯) 1(开灯)]>>>");fgets(buf, sizeof(buf), stdin);buf[strlen(buf) - 1] = '\0';// 向设备文件中写write(fd, buf, sizeof(buf));}close(fd);return 0;
}

三、demo.c

#include <linux/init.h>
#include <linux/module.h>
#include <linux/fs.h>
#include <linux/uaccess.h>
#include <linux/io.h>
#include "head.h"unsigned int major;
char kbuf[128] = {};// 定义指针指向映射后的虚拟内存
unsigned int *vir_rcc;
gpio_t *vir_led1;
gpio_t *vir_led2;
gpio_t *vir_led3;// 封装操作方法
int mycdev_open(struct inode *inode, struct file *file)
{printk("%s:%s:%d", __FILE__, __func__, __LINE__);return 0;
}
int mycdev_release(struct inode *inode, struct file *file)
{printk("%s:%s:%d", __FILE__, __func__, __LINE__);return 0;
}
ssize_t mycdev_read(struct file *file, char *ubuf, size_t size, loff_t *lof)
{printk("%s:%s:%d", __FILE__, __func__, __LINE__);int 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", __FILE__, __func__, __LINE__);int ret;ret = copy_from_user(kbuf, ubuf, size);if (ret){printk("copy_from_user filed\n");return -EIO;}switch (kbuf[0]){case '1':if (kbuf[1] == '0') vir_led1->ODR &= (~(0x1 << 10));else vir_led1->ODR |= (0x1 << 10);break;case '2':              if (kbuf[1] == '0') vir_led2->ODR &= (~(0x1 << 10));else vir_led2->ODR |= (0x1 << 10);break;case '3':              if (kbuf[1] == '0') vir_led3->ODR &= (~(0x1 << 8));else vir_led3->ODR |= (0x1 << 8);break;}return 0;
}
// 定义操作方法结构体对象
struct file_operations fops = {.open = mycdev_open,.read = mycdev_read,.write = mycdev_write,.release = mycdev_release};
// 入口函数，安装内核模块时执行
static int __init mycdev_init(void)
{// static 修饰当前函数只能在本文件使用// int 函数的返回值类型// 注册字符设备驱动// static inline int register_chrdev(unsigned int major, const char *name,//			  const struct file_operations *fops)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);// 寄存器地址映射vir_rcc = ioremap(PHY_RCC_ADDR, 4);if (vir_rcc == NULL){printk("物理内存地址映射失败%d\n", __LINE__);return -ENOMEM;}vir_led1 = ioremap(PHY_LED1_ADDR, 4);if (vir_rcc == NULL){printk("物理内存地址映射失败%d\n", __LINE__);return -ENOMEM;}vir_led2 = ioremap(PHY_LED2_ADDR, 4);if (vir_rcc == NULL){printk("物理内存地址映射失败%d\n", __LINE__);return -ENOMEM;}vir_led3 = ioremap(PHY_LED3_ADDR, 4);if (vir_rcc == NULL){printk("物理内存地址映射失败%d\n", __LINE__);return -ENOMEM;}// 寄存器初始化(*vir_rcc) |= (0x3 << 4);vir_led1->MODER &= (~(0x3 << 20));vir_led1->MODER |= (0x1 << 20);vir_led1->ODR &= (~(0x1 << 10));vir_led2->MODER &= (~(0x3 << 20));vir_led2->MODER |= (0x1 << 20);vir_led2->ODR &= (~(0x1 << 10));vir_led3->MODER &= (~(0x3 << 16));vir_led1->MODER |= (0x1 << 16);vir_led1->ODR &= (~(0x1 << 8));printk("寄存器初始化成功\n");return 0;
}
static void __exit mycdev_exit(void)
{iounmap(vir_led1);iounmap(vir_led2);iounmap(vir_led3);iounmap(vir_rcc);// 注销字符设备驱动unregister_chrdev(major, "mychrdev");
}
module_init(mycdev_init);
module_exit(mycdev_exit);
MODULE_LICENSE("GPL");