1、編寫LED燈的驅動，可以控制三個燈，應用程序中編寫控制燈的邏輯，要使用自動創建設備節點機制

head.h

#ifndef __HEAD_H__
#define __HEAD_H__#define PHY_LED1_MODER 0x50006000
#define PHY_LED1_ODR 0x50006014
#define PHY_LED1_RCC 0x50000A28#define PHY_LED2_MODER 0x50007000
#define PHY_LED2_ODR 0x50007014
#define PHY_LED2_RCC 0x50000A28#define PHY_LED3_MODER 0x50006000
#define PHY_LED3_ODR 0x50006014
#define PHY_LED3_RCC 0x50000A28#endif

mycdev.c

#include <linux/init.h>
#include <linux/module.h>
#include <linux/fs.h>
#include <linux/uaccess.h>
#include <linux/io.h>
#include <linux/device.h>
#include "head.h"
int major;
char kbuf[128] = {0};
// 定義指針接收映射成功的虛擬內存首地址
unsigned int *vir_led1_moder;
unsigned int *vir_led1_odr;
unsigned int *vir_led1_rcc;
unsigned int *vir_led2_moder;
unsigned int *vir_led2_odr;
unsigned int *vir_led2_rcc;
unsigned int *vir_led3_moder;
unsigned int *vir_led3_odr;
unsigned int *vir_led3_rcc;
struct class *cls;
struct device *dev;
// 封裝操作方法
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 filad\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 filed\n");return ret;}if (kbuf[0] == '1' && kbuf[1]== '1') // 開燈{// 開燈邏輯printk("開燈\n");(*vir_led1_odr) |= (0X1 << 10);}if (kbuf[0] == '1' && kbuf[1]== '0') // 關燈{// 關燈邏輯printk("關燈\n");(*vir_led1_odr) &= (~(0X1 << 10));}if (kbuf[0] == '2' && kbuf[1]== '1') // 開燈{// 開燈邏輯printk("開燈\n");(*vir_led2_odr) |= (0X1 << 10);}if (kbuf[0] == '2' && kbuf[1]== '0') // 關燈{// 關燈邏輯printk("關燈\n");(*vir_led2_odr) &= (~(0X1 << 10));}if (kbuf[0] == '3' && kbuf[1]== '1') // 開燈{// 開燈邏輯printk("開燈\n");(*vir_led3_odr) |= (0X1 << 8);}if (kbuf[0] == '3' && kbuf[1]== '0') // 關燈{// 關燈邏輯printk("關燈\n");(*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;
}
// 定義操作方法結構體遍歷并且初始化
struct file_operations fops = {.open = mycdev_open,.read = mycdev_read,.write = mycdev_write,.release = mycdev_close,
};static int __init mycdev_init(void)
{int i;// 注冊字符設備驅動major = register_chrdev(0, "mycdev", &fops);if (major < 0){printk("字符設備驅動注冊失敗\n");return major;}printk("字符設備驅動注冊成功major=%d\n", major);// 向上提交目錄信息cls = class_create(THIS_MODULE, "mycdev");if (IS_ERR(cls)){printk("向上提交目錄信息失敗\n");return -PTR_ERR(cls);}printk("向上提交目錄信息成功\n");// 向上提交設備信息for (i = 0; i < 3; i++){dev = device_create(cls, NULL, MKDEV(major, i), NULL, "mycdev%d", i);if (IS_ERR(dev)){printk("向上提交設備節點失敗\n");return -PTR_ERR(cls);}}printk("向上提交設備節點信息成功\n");// 完成硬件寄存器物理內存的映射vir_led1_moder = ioremap(PHY_LED1_MODER, 4);if (vir_led1_moder == NULL){printk("物理內存映射失敗%d\n", __LINE__);return -EFAULT;}vir_led1_odr = ioremap(PHY_LED1_ODR, 4);if (vir_led1_odr == NULL){printk("物理內存映射失敗%d\n", __LINE__);return -EFAULT;}vir_led1_rcc = ioremap(PHY_LED1_RCC, 4);if (vir_led1_rcc == NULL){printk("物理內存映射失敗%d\n", __LINE__);return -EFAULT;}vir_led2_moder = ioremap(PHY_LED2_MODER, 4);if (vir_led2_moder == NULL){printk("物理內存映射失敗%d\n", __LINE__);return -EFAULT;}vir_led2_odr = ioremap(PHY_LED2_ODR, 4);if (vir_led2_odr == NULL){printk("物理內存映射失敗%d\n", __LINE__);return -EFAULT;}vir_led2_rcc = ioremap(PHY_LED2_RCC, 4);if (vir_led2_rcc == NULL){printk("物理內存映射失敗%d\n", __LINE__);return -EFAULT;}vir_led3_moder = ioremap(PHY_LED3_MODER, 4);if (vir_led3_moder == NULL){printk("物理內存映射失敗%d\n", __LINE__);return -EFAULT;}vir_led3_odr = ioremap(PHY_LED3_ODR, 4);if (vir_led3_odr == NULL){printk("物理內存映射失敗%d\n", __LINE__);return -EFAULT;}vir_led3_rcc = ioremap(PHY_LED3_RCC, 4);if (vir_led3_rcc == NULL){printk("物理內存映射失敗%d\n", __LINE__);return -EFAULT;}printk("物理內存映射成功\n");// 硬件寄存器的初始化(*vir_led1_moder) &= (~(0X3 << 20)); // 設置為輸出(*vir_led1_moder) |= (0X1 << 20);(*vir_led2_moder) &= (~(0X3 << 20)); // 設置為輸出(*vir_led2_moder) |= (0X1 << 20);(*vir_led3_moder) &= (~(0X3 << 16)); // 設置為輸出(*vir_led3_moder) |= (0X1 << 16);// rcc使能(*vir_led1_rcc) |= (0X1 << 4);(*vir_led2_rcc) |= (0X1 << 5);(*vir_led3_rcc) |= (0X1 << 4);// 默認關燈(*vir_led1_odr) &= (~(0X1 << 10));(*vir_led2_odr) &= (~(0X1 << 10));(*vir_led3_odr) &= (~(0X1 << 8)); return 0;
}
static void __exit mycdev_exit(void)
{// 取消物理內存的映射iounmap(vir_led1_moder);iounmap(vir_led1_odr);iounmap(vir_led1_rcc);iounmap(vir_led2_moder);iounmap(vir_led2_odr);iounmap(vir_led2_rcc);iounmap(vir_led3_moder);iounmap(vir_led3_odr);iounmap(vir_led3_rcc);//銷毀設備信息int i;for(i=0;i<3;i++){device_destroy(cls,MKDEV(major,i));}//銷毀目錄信息class_destroy(cls);// 字符設備驅動的注銷unregister_chrdev(major, "mychrdev");
}
module_init(mycdev_init);
module_exit(mycdev_exit);
MODULE_LICENSE("GPL");

test.c

#include <stdio.h>
#include <sys/types.h>
#include <sys/stat.h>
#include <fcntl.h>
#include <stdlib.h>
#include <unistd.h>
#include <string.h>
int main(int argc, const char *argv[])
{char buf[128] = {};int fd = open("/dev/mycdev0",O_RDWR);if(fd < 0){printf("打開設備文件失敗\n");exit(-1);}printf("成功打開設備文件\n");while(1){printf("輸入要實現的邏輯：>\n");fgets(buf,sizeof(buf),stdin);//從終端讀取一個字符存放到bufbuf[strlen(buf)-1]='\0';write(fd,buf,sizeof(buf));}close(fd);return 0;
}

實驗現象

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