[模块化编写驱动控制LED灯]

arm知识-----芯片手册

根据引脚PE10，PF0，PE8，搜索寄存器地址

 RCC_AHB4使能以及AHB4总线作用

 

 

 内核3-4G代码

#include 
#include 
#include 
#include 
#include 
#include "myled.h"
#define CNAME "myled"
//主设备号
int major;
char kbuf[128]={0};
//LED1--PE10
//LED2--PF10
//LED3--PE8
gpio_t *vir_led1_3;
gpio_t *vir_led2;
volatile unsigned int *vir_rcc;
int leds_init()
{
    //将led的物理地址PHY做映射到vir虚拟空间
    //1个寄存器地址是32位，用4字节存放;映射后可以直接使用
    vir_rcc=ioremap(PHY_RCC,4);
    if(vir_rcc==NULL)
    {
        printk("vir_rcc faild\n");
        return -ENOMEM;
    }
    vir_led1_3=ioremap(0x50006000,sizeof(gpio_t));
    if(vir_led1_3==NULL)
    {
        printk("vir_led1_3 faild\n");
        return -ENOMEM;
    }
    vir_led2=ioremap(0x50007000,sizeof(gpio_t));
    if(vir_led2==NULL)
    {
        printk("vir_led2 faild\n");
        return -ENOMEM;
    }
 
//LED1--PE10引脚初始化
    *vir_rcc |= (0x1<<4); //rcc使能
    vir_led1_3->MODER &=(~(0x3<<20));
    vir_led1_3->MODER |=(0x1<<20);//设置gpioe引脚输出模式
    //设置PE10引脚默认输出低电平
    vir_led1_3->ODR &= (~(0x1<<10));
//LED2--PF10引脚初始化
    *vir_rcc |= (0x1<<5); //rcc使能
    vir_led2->MODER &=(~(0x3<<20));
    vir_led2->MODER |=(0x1<<20);//设置gpiof引脚输出模式
    //设置PF10引脚默认输出低电平
    vir_led2->ODR &= (~(0x1<<10));
//LED3--PE8引脚初始化
    vir_led1_3->MODER &=(~(0x3<<16));
    vir_led1_3->MODER |=(0x1<<16);//设置gpioe引脚输出模式
    //设置PE8引脚默认输出低电平
    vir_led1_3->ODR &= (~(0x1<<16));
 
    return 0;
 
}
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 __user *ubuf, size_t size, loff_t *loffs)
{
    int ret;
    printk("%s:%s:%d\n",__FILE__,__func__,__LINE__);
    //校验传输数据大小
    if(size>sizeof(kbuf)) size = sizeof(kbuf);
    ret = copy_to_user(ubuf,kbuf,size);
    if(ret)
    {
        printk("copy from user is error\n");
        return -EIO;
    }
    return size;
}
ssize_t mycdev_write(struct file *file, const char __user *ubuf, size_t size, loff_t *loffs)
{
    int ret;
    printk("%s:%s:%d\n",__FILE__,__func__,__LINE__);
    if(size>sizeof(kbuf))
        size = sizeof(kbuf);
    ret=copy_from_user(kbuf,ubuf,size);
    if(ret)
    {
        printk("copy from user is error\n");
        return -EIO;
    }
    printk("copy from user kbuf=%s\n",kbuf);
    //连接应用层传参
    if(kbuf[0]=='1')
    {
        if(kbuf[1]=='1')
        {
            //led1输出高电平PE10
            vir_led1_3->ODR |= (0x1<<10);
        }
        else if(kbuf[1]=='0')
        {
            vir_led1_3->ODR &= (~(0x1<<10));
        }
    }else if(kbuf[0]=='2')
    {
        if(kbuf[1]=='1')
        {
            //led2输出高电平PF10
            vir_led2->ODR |= (0x1<<10);
        }
        else if(kbuf[1]=='0')
        {
            vir_led2->ODR &= (~(0x1<<10));
        }
    }else if(kbuf[0]=='3')
    {
        if(kbuf[1]=='1')
        {
            //led3输出高电平PE8
            vir_led1_3->ODR |= (0x1<<8);
        }
        else if(kbuf[1]=='0')
        {
            vir_led1_3->ODR &= (~(0x1<<8));
        }
    }
    return size;
}
int  mycdev_close(struct inode *inode, struct file *file)
{
    printk("%s:%s:%d\n",__FILE__,__func__,__LINE__);
    return 0;
}
//结构体中存放函数指针，指向自己定义的函数
const struct file_operations fops = {
        .open = mycdev_open,
        .read = mycdev_read,
        .write = mycdev_write,
        .release = mycdev_close,
};
//入口
static int __init mycdev_init(void)
{
    //1.注册字符设备驱动
    major = register_chrdev(0,CNAME,&fops);
    if(major < 0)
    {
        printk("register chrdev is error\n");
        return major;
    }
    
    printk("major=%d\n",major);
    leds_init();
    return 0;
}
 
//出口
static void __exit mycdev_exit(void)
{
    iounmap(vir_rcc);
 
    iounmap(vir_led1_3);
 
    iounmap(vir_led2);
    //2.注销字符设备驱动
    unregister_chrdev(major,CNAME);
}
module_init(mycdev_init);
module_exit(mycdev_exit);
//许可证
MODULE_LICENSE("GPL");

 应用层0-3G代码：

#include 
#include 
#include 
#include 
#include 
#include 
#include 
char buf[128] = {""};
int main(int argc, char const *argv[])
{
    int fd = -1;
    fd = open("/dev/myled",O_RDWR);
    if(-1 == fd)
    {
        perror("open is error");
        exit(1);
    }
    while(1)
    {
        //控制哪盏灯，1代表LED1
        buf[0]='1';
        write(fd,buf,sizeof(buf));
        //灯亮
        buf[1]='1';
        write(fd,buf,sizeof(buf));
        sleep(1);
        //灯灭
        buf[1]='0';
        write(fd,buf,sizeof(buf));
        sleep(1);
//led2
        buf[0]='2';
        write(fd,buf,sizeof(buf));
        //灯亮
        buf[1]='1';
        write(fd,buf,sizeof(buf));
        sleep(1);
        //灯灭
        buf[1]='0';
        write(fd,buf,sizeof(buf));
        sleep(1);
//led3
        buf[0]='3';
        write(fd,buf,sizeof(buf));
        //灯亮
        buf[1]='1';
        write(fd,buf,sizeof(buf));
        sleep(1);
        //灯灭
        buf[1]='0';
        write(fd,buf,sizeof(buf));
        sleep(1);
    }
 
    close(fd);
    return 0;
}

 测试代码：

#ifndef __LED_H__
#define __LED_H__
//LED1--PE10
//LED2--PF10
//LED3--PE8
#define PHY_RCC  0x50000A28
 
 
typedef struct{
    volatile unsigned int MODER; 
    volatile unsigned int OTYPER;
    volatile unsigned int OSPEEDR;
    volatile unsigned int PUPDR;
    volatile unsigned int IDR;
    volatile unsigned int ODR;
}gpio_t;
#define PHY_GPIOE ((gpio_t*)0x50006000)
#define PHY_GPIOF ((gpio_t*)0x50007000)
int leds_init(void);
#endif

Makefile编写

ARCH?=arm
filename?=myled
ifeq ($(ARCH),arm)
	KERNDIR:=/home/ubuntu/linux-5.10.61
else
	KERNDIR:=/lib/modules/$(shell uname -r)/build  //x86架构
endif
PWD:=$(shell pwd)
all:
	make -C $(KERNDIR) M=$(PWD) modules
clean:
	make -C $(KERNDIR) M=$(PWD) clean
#模块化编译的类型
obj-m:=$(filename).o

实现效果：三盏灯开关控制

对test.c和myled.c分别编译成arm架构

myled.c编译：make ARCH=arm filename=myled

 串口内核启动成功，加载根文件系统，进入用户界面：

安装驱动文件，并执行a.out可执行文件，结果显示如下：并且看到三盏灯亮灭的现象