通过字符设备驱动并编写应用程序控制三盏灯亮灭

本文主要是介绍通过字符设备驱动并编写应用程序控制三盏灯亮灭，希望对大家解决编程问题提供一定的参考价值，需要的开发者们随着小编来一起学习吧！

现象键盘按1三灯全亮按0三灯全灭

头文件.h

#ifndef __HEAD_H__
#define __HEAD_H__
#define PHY_LED1_MODER 0X50006000
#define PHY_LED1_ODR   0X50006014
#define PHY_RCC        0X50000A28#define PHY_LED2_MODER 0X50007000
#define PHY_LED2_ODR   0X50007014#define PHY_LED3_MODER 0X50006000
#define PHY_LED3_ODR   0X50006014#endif

驱动程序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] = {};
// 定义三个指针指向映射后的虚拟内存
unsigned int *vir_led1_moder;
unsigned int *vir_led1_odr;
unsigned int *vir_led2_moder;
unsigned int *vir_led2_odr;
unsigned int *vir_led3_moder;
unsigned int *vir_led3_odr;
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;
}
ssize_t mycdev_read(struct file *file, char *ubuf, size_t size, loff_t *lof)
{printk("%s:%s:%d\n", __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\n", __FILE__, __func__, __LINE__);int ret;ret = copy_from_user(kbuf, ubuf, size);if (ret){printk("copy_from_user filed\n");return -EIO;}if (kbuf[0] == '0') // 关灯{// 关灯逻辑(*vir_led1_odr) &= (~(0X1<<10));//默认关灯(*vir_led2_odr) &= (~(0X1<<10));//默认关灯(*vir_led3_odr) &= (~(0X1<<8));//默认关灯}else if (kbuf[0] == '1'){// 开灯逻辑(*vir_led1_odr) |= (0X1<<10);(*vir_led2_odr) |= (0X1<<10);(*vir_led3_odr) |= (0X1<<8);}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对象
struct file_operations fops = {.open = mycdev_open,.read = mycdev_read,.write = mycdev_write,.release = mycdev_close,
};
static int __init mycdev_init(void)
{// 注册字符设备驱动major = register_chrdev(0, "mychrdev", &fops);if (major < 0){printk("字符设备驱动注册失败\n");return major;}printk("注册字符设备驱动成功major=%d\n", major);// 进行寄存器的地址映射// LED1寄存器地址映射vir_led1_moder = ioremap(PHY_LED1_MODER, 4);if (vir_led1_moder == NULL){printk("物理内存地址映射失败%d\n", __LINE__);return -EFAULT;}vir_led1_odr = ioremap(PHY_LED1_ODR, 4);if (vir_led1_odr == NULL){printk("物理内存地址映射失败%d\n", __LINE__);return -EFAULT;}//LED2寄存器地址映射vir_led2_moder = ioremap(PHY_LED2_MODER, 4);if (vir_led2_moder == NULL){printk("物理内存地址映射失败%d\n", __LINE__);return -EFAULT;}vir_led2_odr = ioremap(PHY_LED2_ODR, 4);if (vir_led2_odr == NULL){printk("物理内存地址映射失败%d\n", __LINE__);return -EFAULT;}//LED3寄存器地址映射vir_led3_moder = ioremap(PHY_LED3_MODER, 4);if (vir_led3_moder == NULL){printk("物理内存地址映射失败%d\n", __LINE__);return -EFAULT;}vir_led3_odr = ioremap(PHY_LED3_ODR, 4);if (vir_led3_odr == NULL){printk("物理内存地址映射失败%d\n", __LINE__);return -EFAULT;}//RCC寄存器地址映射vir_rcc = ioremap(PHY_RCC, 4);if (vir_rcc == NULL){printk("物理内存地址映射失败%d\n", __LINE__);return -EFAULT;}printk("寄存器内存映射成功\n");//LED1寄存器初始化(*vir_rcc) |= (0X3<<4);//GPIOEF控制器时钟使能(*vir_led1_moder) &= (~(0X3<<20));//MODER[21:20]->00(*vir_led1_moder) |= (0X1<<20);//MODER[21:20]->01(*vir_led1_odr) &= (~(0X1<<10));//默认关灯//LED2寄存器初始化(*vir_led2_moder) &= (~(0X3<<20));//MODER[21:20]->00(*vir_led2_moder) |= (0X1<<20);//MODER[21:20]->01(*vir_led2_odr) &= (~(0X1<<10));//默认关灯//LED3寄存器初始化(*vir_led3_moder) &= (~(0X3<<16));//MODER[17:16]->00(*vir_led3_moder) |= (0X1<<16);//MODER[17:16]->01(*vir_led3_odr) &= (~(0X1<<8));//默认关灯return 0;
}
static void __exit mycdev_exit(void)
{//取消内存映射iounmap(vir_led1_moder);iounmap(vir_led1_odr);iounmap(vir_rcc);iounmap(vir_led2_moder);iounmap(vir_led2_odr);iounmap(vir_led3_moder);iounmap(vir_led3_odr);// 注销字符设备驱动unregister_chrdev(major, "mychrdev");
}
module_init(mycdev_init);
module_exit(mycdev_exit);
MODULE_LICENSE("GPL");

应用程序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, char const *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("打开设备文件成功\n");while (1){printf("请输入要进行的操作：0（关灯）1（开灯）>");fgets(buf, sizeof(buf), stdin); // 在终端读一个字符串buf[strlen(buf) - 1] = '\0';write(fd, buf, sizeof(buf)); // 将数据传递给内核}close(fd);return 0;
}

现象为：