作业要求：
通过字符设备驱动分步注册过程实现LED驱动的编写，编写应用程序测试，发布到CSDN
作业答案：
运行效果：
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/slab.h>
#include <linux/cdev.h>
#include <linux/uaccess.h>
#include "head.h"
struct cdev *cdev;
char kbuf[128] = {0};
unsigned int major = 0; // 主设备号
unsigned int minor = 0; // 次设备号
dev_t devno;
struct class *cls;
struct device *dev;
gpio_t *vir_led1;
gpio_t *vir_led2;
gpio_t *vir_led3;
unsigned int *vir_rcc;
// 封装操作方法
// 定义操作方法对象并初始化
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__);
unsigned long ret;
// 向用户空间读取拷贝
if (size > sizeof(kbuf)) // 用户空间期待读取的大小内核满足不了，那就给内核支持的最大大小
size = sizeof(kbuf);
ret = copy_to_user(ubuf, kbuf, size);
if (ret) // 拷贝失败
{
printk("copy_to_user filed\n");
return ret;
}
return 0;
}
ssize_t mycdev_write(struct file *file, const char *ubuf, size_t size, loff_t *lof)
{
unsigned long ret;
// 从用户空间读取数据
if (size > sizeof(kbuf)) // 用户空间期待读取的大小内核满足不了，那就给内核支持的最大大小
size = sizeof(kbuf);
ret = copy_from_user(kbuf, ubuf, size);
if (ret) // 拷贝失败
{
printk("copy_to_user filed\n");
return ret;
}
return 0;
}
long mycdev_ioctl(struct file *file, unsigned int cmd, unsigned long arg)
{
int wh;
int ret=copy_from_user(&wh,(void *)arg,4);
if(ret)//拷贝失败
{
printk("copy_from_user filed\n");
return ret;
}
switch(cmd)
{
case LED_ON:
switch(wh)
{
case 1:
vir_led1->ODR |= (1<<10);
break;
case 2:
vir_led2->ODR |= (1<<10);
break;
case 3:
vir_led3->ODR |= (1<<8);
break;
}
break;
case LED_OFF:
switch(wh)
{
case 1:
vir_led1->ODR &= (~(1<<10));
break;
case 2:
vir_led2->ODR &= (~(1<<10));
break;
case 3:
vir_led3->ODR &= (~(1<<8));
break;
}
break;
}
return 0;
}
int mycdev_close(struct inode *inode, struct file *file)
{
printk("%s:%s:%d\n", __FILE__, __func__, __LINE__);
return 0;
}
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);
//led1
vir_led1->MODER &= (~(3<<20));
vir_led1->MODER |= (1<<20);
vir_led1->ODR &= (~(1<<10));
//led2
vir_led2->MODER &= (~(3<<20));
vir_led2->MODER |= (1<<20);
vir_led2->ODR &= (~(1<<10));
//led3
vir_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;
}
// 定义操作方法结构体变量并赋值
struct file_operations fops={
.open=mycdev_open,
.read=mycdev_read,
.write=mycdev_write,
.unlocked_ioctl=mycdev_ioctl,
.release=mycdev_close,
};
static int __init mycdev_init(void)
{
int ret;
// 1.申请字符设备驱动对象空间
cdev = cdev_alloc();
if (cdev == NULL)
{
return -EFAULT;
}
printk("字符设备驱动对象申请成功\n");
// 2.初始化字符设备驱动对象
cdev_init(cdev, &fops);
// 3.申请设备号
if (major == 0) // 动态申请
{
ret = alloc_chrdev_region(&devno, minor, 3, "myled");
if (ret)
{
printk("动态申请设备号失败\n");
goto out1;
}
// 为了统一和静态申请设备号的操作
major = MAJOR(devno);
minor = MINOR(devno);
}
else // 静态指定
{
ret = register_chrdev_region(MKDEV(major, minor), 3, "myled");
if (ret)
{
printk("静态申请设备号失败\n");
goto out1;
}
}
printk("设备号申请成功\n");
// 4.注册驱动
ret = cdev_add(cdev, MKDEV(major, minor), 3);
if (ret)
{
printk("注册驱动失败\n");
goto out2;
}
printk("注册驱动成功\n");
// 5.向上提交目录
cls = class_create(THIS_MODULE, "led");
if (IS_ERR(cls))
{
printk("向上提交目录失败\n");
ret = -PTR_ERR(cls);
goto out3;
}
printk("向上提交目录成功\n");
// 6.向上提交设备节点
int i;
for (i = 0; i < 3; i++)
{
dev = device_create(cls, NULL, MKDEV(major, i), NULL, "myled%d", i);
if (IS_ERR(dev))
{
printk("向上提交设备信息失败\n");
ret = -PTR_ERR(dev);
goto out4;
}
}
printk("向上提交设备信息成功\n");
// 寄存器映射以及初始化
all_led_init();
return 0;
out4:
// 销毁提交成功的设备信息
for (--i; i >= 0; i--)
{
device_destroy(cls, MKDEV(major, i));
}
// 销毁目录
class_destroy(cls);
out3:
cdev_del(cdev);
out2:
unregister_chrdev_region(MKDEV(major, minor), 3);
out1:
kfree(cdev);
return ret;
}
static void __exit mycdev_exit(void)
{
// 1.释放设备信息
int i;
for (i = 0; i < 3; i++)
{
device_destroy(cls, MKDEV(major, i));
}
// 2.销毁目录
class_destroy(cls);
// 3.注销驱动对象
cdev_del(cdev);
// 4.释放设备号
unregister_chrdev_region(MKDEV(major, minor), 3);
// 5.释放对象空间
kfree(cdev);
}
module_init(mycdev_init);
module_exit(mycdev_exit);
MODULE_LICENSE("GPL");应用程序：
#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;
int fd=open("/dev/myled0",O_RDWR);
if(fd<0)
{
printf("打开设备文件失败\n");
exit(-1);
}
while(1)
{
//从终端读取
printf("请输入要实现的功能\n");
printf("0(关灯) 1(开灯)\n");
printf("请输入>");
scanf("%d",&a);
printf("请输入要控制的灯\n");
printf("1(LED1) 2(LED2) 3(LED3)\n");
printf("请输入>");
scanf("%d",&b);
switch(a)
{
case 1:
ioctl(fd,LED_ON,&b);
break;
case 0:
ioctl(fd,LED_OFF,&b);
break;
}
}
close(fd);
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
//构建功能码
#define LED_ON _IOW('l',1,int)
#define LED_OFF _IOW('l',0,int)
#endif 
