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 RCC 0x50000A28
#define LED1_ADDR 0x50006000
#define LED2_ADDR 0x50007000
#define LED3_ADDR 0x50006000
#define LED_ON _IOW('l',1,int)
#define LED_OFF _IOW('l',0,int)
#endif
应用层文件
#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 fd;
fd=open("/dev/myled0",O_RDWR);
if(fd<0)
{
printf("打开设备文件失败\n");
exit(-1);
}
int a,b;
while (1)
{
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("请输入控制的灯\n");
printf("1(LED1)2(LED2)3(LED3)\n");
scanf("%d",&b);
switch (a)
{
case 1:
ioctl(fd,LED_ON,&b);
break;
case 0:
ioctl(fd,LED_OFF,&b);
break;
default:
printf("输入错误\n");
break;
}
}
close(fd);
return 0;
}驱动文件
#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;
unsigned int major=0;//主设备号
unsigned int minor=0;//次设备号
char kbuf[128]={0};
struct class *cls;
struct device *dev;
unsigned int *vir_rcc;
gpio_t *vir_led1;
gpio_t *vir_led2;
gpio_t *vir_led3;
dev_t devno;
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;
if(size>sizeof(kbuf))
size=sizeof(kbuf);
ret=copy_to_user(ubuf,kbuf,size);
if(ret)
{
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;
if(size>sizeof(kbuf))
size=sizeof(kbuf);
ret=copy_from_user(kbuf,ubuf,size);
if(ret)
{
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)
{
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)
{
vir_led1=ioremap(LED1_ADDR,sizeof(gpio_t));
if(vir_led1==NULL)
{
printk("led1内存映射失败");
return -ENOMEM;
}
printk("led1内存映射成功");
vir_led2=ioremap(LED2_ADDR,sizeof(gpio_t));
if(vir_led2==NULL)
{
printk("led2内存映射失败");
return -ENOMEM;
}
printk("led2内存映射成功");
vir_led3=ioremap(LED3_ADDR,sizeof(gpio_t));
if(vir_led3==NULL)
{
printk("led3内存映射失败");
}
printk("led3内存映射成功");
vir_rcc=ioremap(RCC,4);
if(vir_rcc==NULL)
{
printk("rcc内存映射失败");
}
printk("rcc内存映射成功");
//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;
}
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;
//申请字符设备的驱动空间
cdev = cdev_alloc();
if (cdev == NULL)
{
return -EFAULT;
}
printk("字符设备驱动对象申请成功\n");
//初始化驱动对象
cdev_init(cdev,&fops);
//动态申请
if(major==0)
{
ret=alloc_chrdev_region(&devno,minor, 3,"myled");
if(ret)
{
printk("动态申请设备号失败\n");
goto out1;
}
major=MAJOR(devno);
minor=MAJOR(devno);
}
//静态指定
else
{
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");
//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");
//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");
//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:
//销毁提交设备成功的设备信息
for ( --i; i>=0; i--)
{
device_destroy(cls,MKDEV(major,i));
/* code */
}
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)
{
//取消地址映射
iounmap(vir_rcc);
iounmap(vir_led1);
iounmap(vir_led2);
iounmap(vir_led3);
//销毁设备节点
int i;
for ( i = 0; i < 3; i++)
{
device_destroy(cls,MKDEV(major,i));
}
//销毁目录
class_destroy(cls);
//注销驱动对象
cdev_del(cdev);
//释放设备号
unregister_chrdev_region(MKDEV(major,minor),3);
//释放空间
kfree(cdev);
}
module_init(mycdev_init);
module_exit(mycdev_exit);
MODULE_LICENSE("GPL");makefile
arch?=arm
modname?=register_dev_c
ifeq ($(arch),arm)
KERNELDIR:=/home/ubuntu/linux-5.10.61
else
KERNELDIR:=/lib/modules/$(shell uname -r)/build
endif
PWD:=$(shell pwd)
all:
make -C $(KERNELDIR) M=$(PWD) modules
clean:
make -C $(KERNELDIR) M=$(PWD) clean
obj-m:= $(modname).o
执行效果
开发板效果
