思维导图

练习

1.编写LED灯的驱动，可以控制三个灯，应用程序中编写控制灯的逻辑，要使用自动创建设备节点机制
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 ORD;
}gpio_t;#define GPIOE 0x50006000
#define GPIOF 0x50007000
#define RCC   0x50000A28#endif

mychrdev.c

#include <linux/init.h>
#include <linux/module.h>
#include <linux/fs.h>
#include <linux/uaccess.h>
#include <linux/io.h>
#include "head.h"
#include <linux/device.h>unsigned int major; // 定义一个变量保存主设备号
char kbuf[128] = {0};unsigned int *rcc;
gpio_t *led1;
gpio_t *led2;
gpio_t *led3;struct class *cls;
struct device *dev;// 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 failed\n");return ret;}return 0;
}
ssize_t mycdev_write(struct file *file, const char *ubuf, size_t size, loff_t *lof)
{int ret;ret = copy_from_user(kbuf, ubuf, size);if (ret){printk("copy_from_user failed\n");return ret;}switch (kbuf[0])//选灯{case '1':if (kbuf[1] == '1')//开灯led1->ORD |= (0x1 << 10);else if (kbuf[1] == '0')//关灯led1->ORD &= (~(0x1 << 10));break;case '2':if (kbuf[1] == '1')led2->ORD |= (0x1 << 10);else if (kbuf[1] == '0')led2->ORD &= (~(0x1 << 10));break;case '3':if (kbuf[1] == '1')led3->ORD |= (0x1 << 8);else if (kbuf[1] == '0')led3->ORD &= (~(0x1 << 8));break;}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,.release = mycdev_close,.read = mycdev_read,.write = mycdev_write,
};static int __init mycdev_init(void)
{int i;// 注册字符设备驱动major = register_chrdev(0, "mychrdev", &fops);if (major < 0){printk("注册字符设备驱动失败\n");return major;}printk("注册字符设备驱动成功major=%d\n", major);//向上提交目录信息cls = class_create(THIS_MODULE, "mychrdev");if(IS_ERR(cls)){printk("向上提交目录信息失败\n");return -PTR_ERR(cls);}printk("向上提交目录信息成功\n");//向上提交设备信息for (i=0; i<3; i++){dev = device_create(cls, NULL, MKDEV(major, i), NULL, "mychrdev%d", i);if (IS_ERR(dev)){printk("向上提交设备节点失败\n");return -PTR_ERR(cls);}}printk("向上提交设备节点成功\n");// 完成硬件寄存器物理内存的映射led1 = ioremap(GPIOE, sizeof(gpio_t));if (led1 == NULL){printk("led1物理内存映射失败\n");return -EFAULT;}led2 = ioremap(GPIOF, sizeof(gpio_t));if (led2 == NULL){printk("led2物理内存映射失败\n");return -EFAULT;}led3 = ioremap(GPIOE, sizeof(gpio_t));if (led3 == NULL){printk("led3物理内存映射失败\n");return -EFAULT;}rcc = ioremap(RCC, 4);if (rcc == NULL){printk("rcc物理内存映射失败\n");return -EFAULT;}printk("物理内存映射成功\n");//rcc使能(*rcc) |= (0x3 << 4);//硬件寄存器初始化led1->MODER &= (~(0x3 << 20));led1->MODER |= (0x1 << 20);led2->MODER &= (~(0x3 << 20));led2->MODER |= (0x1 << 20);led3->MODER &= (~(0x3 << 16));led3->MODER |= (0x1 << 16);//默认关灯led1->ORD &= (~(0x1 << 10));led2->ORD &= (~(0x1 << 10));led3->ORD &= (~(0x1 << 8));return 0;
}static void __exit mycdev_exit(void)
{int i;// 取消物理内存的映射iounmap(rcc);iounmap(led1);iounmap(led2);iounmap(led3);//销毁设备信息for(i=0; i<3; i++)device_destroy(cls, MKDEV(major, i));//销毁目录信息class_destroy(cls);// 注销字符设备驱动unregister_chrdev(major, "mychrdev");
}module_init(mycdev_init);
module_exit(mycdev_exit);
MODULE_LICENSE("GPL");

test.c

#include <stdio.h>
#include <unistd.h>
#include <sys/types.h>
#include <sys/stat.h>
#include <fcntl.h>
#include <stdlib.h>
#include <string.h>int main(int argc, char const *agrv[])
{char buf[128] = {0};int fd = open("/dev/mychrdev0", O_RDWR);if (fd < 0){printf("打开设备文件失败\n");exit(-1);}while (1){printf("请输入LED控制方式:(11(LED1开))> ");fgets(buf, sizeof(buf), stdin); // 从终端输入数据到bufbuf[strlen(buf) - 1] = '\0';    // 将buf末尾的'\n'切换为'\0'write(fd, buf, sizeof(buf));}close(fd);return 0;
}