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
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 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 _IOW('l',1,int)
#define LED_OFF _IOW('l',0,int)
#endif demo1.c
#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 "head.h"
char kbuf[128]={0};
gpio_t *vir_led1;
gpio_t *vir_led2;
gpio_t *vir_led3;
unsigned int *vir_rcc;
struct cdev *cdev;
dev_t devno;
unsigned int major=0;
unsigned int minor=0;
struct class *cls;
struct device *dev;
int mycdev_open(struct inode *inode, struct file *file)
{
int min=MINOR(inode->i_rdev);
file->private_data=(void*)min;
printk("%s:%s:%d\n",__FILE__,__func__,__LINE__);
return 0;
}
long mycdev_ioctl(struct file *file,unsigned int cmd,unsigned long arg)
{
int min=(int)file->private_data;
switch(min)
{
case 0:
switch (cmd)
{
case LED_ON:
vir_led1->ODR |= (0x1 << 10);
break;
case LED_OFF:
vir_led1->ODR &= (~(0X1 << 10));
break;
}
break;
case 1:
switch (cmd)
{
case LED_ON:
vir_led2->ODR |= (0X1 << 10);
break;
case LED_OFF:
vir_led2->ODR &= (~(0X1 << 10));
break;
}
break;
case 2:
switch (cmd)
{
case LED_ON:
vir_led3->ODR |= (0X1 << 8);
break;
case LED_OFF:
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,
};
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_led1->MODER |= (1<<16);
vir_led1->ODR &= (~(1<<8));
printk("寄存器初始化成功\n");
return 0;
}
static int __init mycdev_init(void)
{
//字符设备驱动注册
int ret;
cdev=cdev_alloc();
if(cdev == NULL)
{
printk("申请对象失败\n");
ret=-EFAULT;
goto out1;
}
printk("申请对象成功\n");
cdev_init(cdev,&fops);
if(major == 0)
{
ret = alloc_chrdev_region(&devno,minor,3,"mychrdev");
if(ret)
{
printk("申请设备号失败\n");
goto out2;
}
printk("申请设备号成功\n");
major=MAJOR(devno);
minor=MINOR(devno);
}
ret=cdev_add(cdev,MKDEV(major,minor),3);
if(ret)
{
printk("注册对象失败\n");
goto out3;
}
printk("注册对象成功\n");
cls=class_create(THIS_MODULE,"mychrdev");
if(IS_ERR(cls))
{
printk("向上提交目录失败\n");
goto out4;
}
printk("向上提交目录成功\n");
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("向上提交设备节点失败\n");
goto out5;
}
}
printk("向上提交设备节点成功\n");
//寄存器映射以及初始化
all_led_init();
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)
{
//取消地址映射
iounmap(vir_led1);
iounmap(vir_led2);
iounmap(vir_rcc);
int i;
for(i=0;i<3;i++)
{
device_destroy(cls,MKDEV(major,i));
}
class_destroy(cls);
//注销字符设备驱动
cdev_del(cdev);
unregister_chrdev_region(MKDEV(major,minor),3);
kfree(cdev);
}
module_init(mycdev_init);
module_exit(mycdev_exit);
MODULE_LICENSE("GPL");text.c
#include<stdlib.h>
#include<stdio.h>
#include <sys/types.h>
#include <sys/stat.h>
#include <fcntl.h>
#include <sys/ioctl.h>
#include<unistd.h>
#include<string.h>
#include "head.h"
int main(int argc, char const *argv[])
{
int fd;
char name[20]={0};
int a,b;
while(1)
{
printf("请选择要控制的灯：1（LED1）2(LED2) 3(LED3)\n");
printf("请输入>");
scanf("%d",&b);
switch(b)
{
case 1:
strcpy(name,"/dev/myled0");
break;
case 2:
strcpy(name,"/dev/myled1");
break;
case 3:
strcpy(name,"/dev/myled2");
break;
}
fd=open(name,O_RDWR);
if(fd<0)
{
printf("打开设备文件失败\n");
exit(-1);
}
//从终端读取
printf("请输入要实现的功能:0(关灯) 1(开灯)\n");
printf("请输入>");
scanf("%d",&a);
switch(a)
{
case 1:
ioctl(fd,LED_ON);
break;
case 0:
ioctl(fd,LED_OFF);
break;
}
}
close(fd);
return 0;
}
