LED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__
#define PHY_LED13_MODER 0x50006000 //[20 21]/[16 17] >01
#define PHY_LED13_ODR 0x50006014 // [10]/[8]
#define PHY_LED2_MODER 0x50007000 //[20 21] >01
#define PHY_LED2_ODR 0x50007014 //10
#define PHY_RCC 0x50000A28 //4 5位
#define LED_ON _IOW('l',1,int *)
#define LED_OFF _IOW('l',0,int *)
#endiftext.c
#include
#include
#include
#include
#include
#include
#include
#include "head.h"
int main(int argc,const char * argv[])
{
int a;
int b;
while(1)
{
int fd;
//从中断获取我们想实现的功能功能
printf("请选择要控制的灯:0-LED1,1-LED2,2-LED3\n");
scanf("%d",&a);
switch(a)
{
case 1:
fd = open("/dev/mycdev0",O_RDWR);
break;
case 2:
fd = open("/dev/mycdev1",O_RDWR);
break;
case 3:
fd = open("/dev/mycdev2",O_RDWR);
break;
}
if(fd<0)
{
printf("打开设备文件失败\n");
return -1;
}
printf("打开设备文件成功\n");
printf("请输入想要实现的功能 ");
printf("0(关灯)1(开灯)\n");
printf("请输入:");
scanf("%d",&b);
switch (b)
{
case 1:
ioctl(fd,LED_ON,&b);
break;
case 0:
ioctl(fd,LED_OFF,&b);
break;
}
close(fd);
}
return 0;
} demo.c
#include
#include
#include
#include
#include
#include
#include
#include
#include
#include "head.h"
struct class *cls;
struct device *dev;
unsigned int *vir_moder13;
unsigned int *vir_moder2;
unsigned int *vir_odr13;
unsigned int *vir_odr2;
unsigned int *vir_rcc;
char kbuf[128]={};
//封装操作方法
int mycdev_open(struct inode * inode,struct file* file)
{
unsigned int min=MINOR(inode->i_rdev);//获取打开的文件的次设备号
file->private_data=(void *)min;
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;
ret=copy_to_user(ubuf,kbuf,size);
if(ret)
{
printk("copy to user filed\n");
return -EIO;
}
return 0;
}
ssize_t mycdev_write(struct file * file,const char *ubuf,size_t size,loff_t *lof)
{
printk("%s:%s:%d\n",__FILE__,__func__,__LINE__);
unsigned long ret;
ret=copy_from_user(kbuf,ubuf,size);
if(ret)
{
printk("copy from user filed\n");
return -EIO;
}
//控制LED灯
if(kbuf[0]=='0')//关灯
{
(*vir_odr13)&=~(0x1<<10);
(*vir_odr13)&=~(0x1<<8);
(*vir_odr2)&=~(0x1<<10);
}
else if(kbuf[0]=='1')//开LED1
{
(*vir_odr13)|=(0x1<<10);
}
else if(kbuf[0]=='2')//开LED2
{
(*vir_odr2)|=(0x1<<10);
}
else if(kbuf[0]=='3')//开LED3
{
(*vir_odr13)|=(0x1<<8);
}
return 0;
}
*/
int mycdev_close(struct inode * indode,struct file* file)
{
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;//获取文件的次设备号
switch(min)
{
case 0://LED1
switch(cmd)
{
case LED_ON://开灯
(*vir_odr13) |=(0x1<<10);
break;
case LED_OFF://关灯
(*vir_odr13) &=~(0x1<<10);
break;
}
break;
case 1://LED2
switch(cmd)
{
case LED_ON://开灯
(*vir_odr2) |=(0x1<<10);
break;
case LED_OFF://关灯
(*vir_odr2) &=~(0x1<<10);
break;
}
break;
case 2://LED3
switch(cmd)
{
case LED_ON://开灯
(*vir_odr13) |=(0x1<<8);
break;
case LED_OFF://关灯
(*vir_odr13) &=~(0x1<<8);
break;
}
break;
}
return 0;
}
struct file_operations fops = {
.open=mycdev_open,
//.read=mycdev_read,
//.write=mycdev_write,
.unlocked_ioctl = mycdev_ioctl,
.release=mycdev_close,
};
struct cdev* cdev;
unsigned int major=0;
unsigned int minor=0;
dev_t devno;
static int __init mycdev_init(void)
{
int i;
//注册字符设备驱动
//1.申请一个对象空间cdev_alloc
int ret;
cdev=cdev_alloc();
if(cdev==NULL)
{
printk("申请字符设备驱动对象空间失败\n");
ret =-EFAULT;
goto out1;
}
printk("申请字符设备驱动对象空间成功\n");
//2.初始化对象cdev_init
cdev_init(cdev,&fops);
//3.申请设备号 register_chrdev_region()/alloc_chrdev_region()
if(major==0)//动态申请
{
ret=alloc_chrdev_region(&devno,minor,3,"mychrdev");
if(ret)
{
printk("动态申请设备号失败\n");
goto out2;
}
major=MAJOR(devno);//根据设备号获取主设备号
minor=MINOR(devno);//根据设备号获取次设备号
}
else//静态申请
{
ret=register_chrdev_region(MKDEV(major,minor),3,"mychrdev");
if(ret)
{
printk("静态申请设备号失败\n");
goto out2;
}
}
printk("设备号申请成功\n");
//4.注册驱动对象 cdev_add
ret=cdev_add(cdev,MKDEV(major,minor),3);
if(ret)
{
printk("注册字符设备驱动对象失败\n");
goto out3;
}
printk("注册字符设备驱动对象成功\n");
if(major<0)
{
printk("字符设备驱动注册失败\n");
return major;
}
printk("字符设备驱动成功major=%d\n",major);
//5.向上提交目录 class_create
cls=class_create(THIS_MODULE,"mychrdev");
if(IS_ERR(cls))
{
printk("想上提交目录失败\n");
goto out4;
}
printk("想上提交目录成功\n");
//6.向上提交设备节点信息 device_create
for(i=0;i<3;i++)
{
dev=device_create(cls,NULL,MKDEV(major,i),NULL,"mycdev%d",i);
if(IS_ERR(dev))
{
printk("想上提交设备节点失败\n");
goto out5;
}
}
printk("想上提交设备节点成功\n");
//进行寄存器的地址映射
vir_moder13 = ioremap(PHY_LED13_MODER,4);
if(vir_moder13 == NULL)
{
printk("物理内存地址映射失败%d\n",__LINE__);
return -EFAULT;
}
vir_moder2 = ioremap(PHY_LED2_MODER,4);
if(vir_moder13 == NULL)
{
printk("物理内存地址映射失败%d\n",__LINE__);
return -EFAULT;
}
vir_odr13 = ioremap(PHY_LED13_ODR,4);
if(vir_odr13 == NULL)
{
printk("物理内存地址映射失败%d\n",__LINE__);
return -EFAULT;
}
vir_odr2 = ioremap(PHY_LED2_ODR,4);
if(vir_odr2 == NULL)
{
printk("物理内存地址映射失败%d\n",__LINE__);
return -EFAULT;
}
vir_rcc = ioremap(PHY_RCC,4);
if(vir_rcc == NULL)
{
printk("物理内存地址映射失败%d\n",__LINE__);
return -EFAULT;
}
printk("寄存器内存映射成功\n");
//寄存器初始化
//rcc初始化
(*vir_rcc) |= (0x3<<4);//GPIOEF控制器时钟使能
(*vir_moder13) &= ~(0x3<<20);
(*vir_moder13) |= (0x1<<20);//LED1
(*vir_moder13) &= ~(0x3<<16);
(*vir_moder13) |= (0x1<<16);//LED3
(*vir_moder2) &= ~(0x3<<20);
(*vir_moder2) |= (0x1<<20);//LED2
(*vir_odr13) &=~(0x1<<10);//LED1
(*vir_odr13) &=~(0x1<<8);//LED3
(*vir_odr2) &=~(0x1<<10);//LED2
return 0;
printk("初始化LED成功");
out5:
//当提交设备节点中途失败时，将提交成功的节点释放
for(i--;i>=0;i--)
{
device_destroy(cls,MKDEV(major,i));
}
//销毁目录
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)
{
int i;
//取消内存映射
iounmap(vir_moder13);
iounmap(vir_moder2);
iounmap(vir_odr13);
iounmap(vir_odr2);
iounmap(vir_rcc);
//1.销毁设备节点信息
for(i=0;i<3;i++)
{
device_destroy(cls,MKDEV(major,i));
}
//2.销毁目录
class_destroy(cls);
//3.注销字符设备驱动对象
cdev_del(cdev);
//4.释放设备号
unregister_chrdev_region(MKDEV(major,minor),3);
//5.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");