Linux内核驱动点灯

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
#endif 

Makefile：

modname?=mychrdev
arch?=arm

ifeq ($(arch),arm)
KERNELDIR:=/home/ubuntu/FSMP1A/linux-stm32mp-5.10.61-stm32mp-r2-r0/linux-5.10.61 #用于编译生成ARM架构的模块
else
KERNELDIR :=/lib/modules/$(shell uname -r )/build #用于生产x86架构的模块
endif

#定义变量保存模块化编译的文件路径
PWD:=$(shell pwd)

all:

#M=$(PWD)指定模块化编译的路径
	make -C $(KERNELDIR) M=$(PWD) modules
clean: #编译清除
	make -C $(KERNELDIR) M=$(PWD) clean

obj-m:=$(modname).o #指定将demo.o独立连接生产内核模块文件

test.c：

#include
#include
#include 
#include 
#include 
#include
#include
 
 
int main(int argc, char const *argv[])
{
    char buf[128]={0};
    int fd=open("/dev/mychrdev",O_RDWR);
    if(fd<0)
    {
        printf("打开设备文件失败\n");
        exit(-1);
    }
    while(1)
    {
        //从终端读取
        printf("请输入两个字符\n");
        printf("第一个字符:1(LED1) 2(LED2) 3(LED3)\n");
        printf("第二个字符:0(关灯) 1(开灯)\n");
        printf("请输入>");
        fgets(buf,sizeof(buf),stdin);
        buf[strlen(buf)-1]='\0';
        //向设备文件中写
        write(fd,buf,sizeof(buf));
    }
 
    
    close(fd);
 
    return 0;
}

led.c：

#include 
#include 
#include
#include
#include"head.h"
 
int major;
char kbuf[128]={0};
gpio_t *vir_led1;
gpio_t *vir_led2;
gpio_t *vir_led3;
unsigned int *vir_rcc;
struct class *cls;
struct device *dev;
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;
    //向用户空间读取拷贝
    if(size>sizeof(kbuf))//用户空间期待读取的大小内核满足不了，那就给内核支持的最大大小
        size=sizeof(kbuf);
    ret=copy_to_user(ubuf,kbuf,size);
    if(ret)//拷贝失败
    {
        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;
    //从用户空间读取数据
    if(size>sizeof(kbuf))//用户空间期待读取的大小内核满足不了，那就给内核支持的最大大小
        size=sizeof(kbuf);
    ret=copy_from_user(kbuf,ubuf,size);
    if(ret)//拷贝失败
    {
        printk("copy_to_user filed\n");
        return ret;
    }
    switch(kbuf[0]){
        case '1'://LED1
            if(kbuf[1]=='0')//关灯
                vir_led1->ODR &= (~(1<<10));
            else//开灯
                vir_led1->ODR |= 1<<10;
            break;
        case '2'://LED2
            if(kbuf[1]=='0')//关灯
                vir_led2->ODR &= (~(1<<10));
            else//开灯
                vir_led2->ODR |= 1<<10;
            break;
        case '3'://LED3
            if(kbuf[1]=='0')//关灯
                vir_led3->ODR &= (~(1<<8));
            else//开灯
                vir_led3->ODR |= 1<<8;
            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,
    .read=mycdev_read,
    .write=mycdev_write,
    .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
    major=register_chrdev(0,"mychrdev",&fops);
    if(major<0)
    {
        printk("字符设备驱动注册失败\n");
        return major;
    }
    printk("字符设备驱动注册成功:major=%d\n",major);
 
    //寄存器映射以及初始化
    all_led_init();
 
    return 0;
}
static void __exit mycdev_exit(void)
{
    //取消地址映射
    iounmap(vir_led1);
    iounmap(vir_led2);
    iounmap(vir_rcc);
    //注销字符设备驱动
    unregister_chrdev(major,"mychrdev");
 
 
}
module_init(mycdev_init);
module_exit(mycdev_exit);
MODULE_LICENSE("GPL");