day4驱动开发

目的：通过字符设备驱动的分步实现编写LED驱动，另外实现特备文件和设备的绑定

驱动文件：

#include <linux/init.h>
#include <linux/module.h>
#include <linux/fs.h>
#include <linux/device.h>
#include <linux/cdev.h>
#include <linux/slab.h>
#include <linux/io.h>
#include "head.h"

struct cdev *cdev;
unsigned int major = 0;
unsigned int minor = 0;
struct class *cls;
struct device *dev;


gpio_t *vir_led1;
gpio_t *vir_led2;
gpio_t *vir_led3;
unsigned int *vir_rcc;

int mycdev_open (struct inode * inode, struct file * file)
{
	printk("%s : %s : %d\n",__FILE__,__func__,__LINE__);

	int min = MINOR(inode->i_rdev);
	file->private_data = (void *)min;

	return 0;
}

long mycdev_ioctl(struct file *file, unsigned int cmd, unsigned long arg)
{
	printk("%s : %s : %d\n",__FILE__,__func__,__LINE__);

	int which = (int)file->private_data;
	printk("which = %d\n",which);

	switch(cmd)
	{
	case LED_ON:
		switch(which)
		{
		case 0://LED1
			vir_led1->ODR |= (0x1 << 10);
			break;
		case 1://LED2
			vir_led2->ODR |= (0x1 << 10);
			break;
		case 2://LED3
			vir_led3->ODR |= (0x1 << 8);
			break;
		}
		break;
		{
		case LED_OFF:
			switch(which)
			{
			case 0://LED1
				vir_led1->ODR &= (~(0x1 << 10));
				break;
			case 1://LED2
				vir_led2->ODR &= (~(0x1 << 10));
				break;
			case 2://LED3
				vir_led3->ODR &= (~(0x1 << 8));
				break;
			}
		}
		break;
	}




	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变量并赋值
struct file_operations fops =
{
	.open = mycdev_open,
	.unlocked_ioctl = mycdev_ioctl,
	.release = mycdev_close,
};


static int __init mycdev_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");


	int ret;

	//申请一个对象空间
	cdev = cdev_alloc();
	if(cdev == NULL)
	{
		printk("cdev_alloc failed\n");
		ret = -EFAULT;
		goto out1;
	}
	printk("cdev_alloc success\n");
	//初始化对象
	cdev_init(cdev,&fops);
	//申请设备号
	if(major == 0)//动态申请
	{
		dev_t devnu;
		ret = alloc_chrdev_region(&devnu,minor,3,"mydev");
		if(ret)
		{
			printk("alloc_chrdev_region failed\n");
			goto out2;
		}
		major = MAJOR(devnu);
		minor = MINOR(devnu);
		printk("alloc_chrdev_region success\n");
	}
	else//静态申请
	{
		ret = register_chrdev_region(major,3,"mydev");
		if(ret)
		{
			printk("register_chrdev_region failed\n");
			goto out2;
		}
		printk("register_chrdev_region success\n");
	}
	//注册驱动对象
	ret = cdev_add(cdev,MKDEV(major,minor),3);
	if(ret)
	{
		printk("cdev_add failed\n");
		goto out3;
	}
	printk("cdev_add success\n");
	//向上提交目录
	cls = class_create(THIS_MODULE,"mychrdev");
	if(IS_ERR(cls))
	{
		printk("class_create failed\n");
		goto out4;
	}
	printk("class_create success\n");
	//向上提交节点信息
	int i;
	for(i=0;i<3;i++)
	{
		dev = device_create(cls,NULL,MKDEV(major,i),NULL,"mychrdev%d",i);
		if(IS_ERR(dev))
		{
			printk("device_create failed\n");
			goto out5;
		}
	}
	printk("device_create success\n");

	return 0;
out5:
	for(--i;i>=0;i--)
	{
		device_destroy(cls,MKDEV(major,i));
	}
	class_destroy(cls);
out4:
	cdev_del(cdev);

out3:
	unregister_chrdev_region(MKDEV(major,minor),3);

out2:
	kfree(cdev);

out1:
	return ret;



}

static void __exit mycdev_exit(void)
{
	//销毁设备节点信息
	int i;
	for(i=0;i<3;i++)
	{
		device_destroy(cls,MKDEV(major,i));
	}
	//销毁目录
	class_destroy(cls);
	//销毁字符设备驱动对象
	cdev_del(cdev);
	//释放设备号
	unregister_chrdev_region(MKDEV(major,minor),3);
	//释放申请到的字符设备驱动对象空间
	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 <sys/ioctl.h>
#include <fcntl.h>
#include <unistd.h>
#include <string.h>
#include "head.h"

int main(int argc, char const *argv[])
{
	// 打开第一个设备文件
	int fd1 = open("/dev/mychrdev0", O_RDWR);
	if (fd1 < 0)
	{
		printf("打开设备文件失败\n");
		exit(-1);
	}
	// 打开第二个设备文件
	int fd2 = open("/dev/mychrdev1", O_RDWR);
	if (fd2 < 0)
	{
		printf("打开设备文件失败\n");
		exit(-1);
	}
	// 打开第三个设备文件
	int fd3 = open("/dev/mychrdev2", O_RDWR);
	if (fd3 < 0)
	{
		printf("打开设备文件失败\n");
		exit(-1);
	}

	while (1)
	{
		int a, b;
		// 从终端读取
		printf("请输入字符\n");
		printf("第一个字符:1(LED1) 2(LED2) 3(LED3)\n");
		scanf("%d", &a);
		printf("第二个字符:0(关灯) 1(开灯)\n");
		printf("请输入>");
		scanf("%d", &b);
		// 向设备文件中写
		switch (b)
		{
		case 1:
			switch (a)
			{
			case 1: // LED1
				ioctl(fd1, LED_ON);
				break;
			case 2: // LED2
				ioctl(fd2, LED_ON);
				break;
			case 3: // LED3
				ioctl(fd3, LED_ON);
				break;
			}
			break;
		case 0:
			switch (a)
			{
			case 1: // LED1
				ioctl(fd1, LED_OFF);
				break;
			case 2: // LED2
				ioctl(fd2, LED_OFF);
				break;
			case 3: // LED3
				ioctl(fd3, LED_OFF);
				break;
			}
			break;
		}
	}

	close(fd1);
	close(fd2);
	close(fd3);

	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

#define LED_ON _IO('l',1)
#define LED_OFF _IO('l',0)


#endif