驱动编写LED灯

 demo.c

#include 
#include 
#include 
#include 
#include
#include "head.h"
unsigned int major;
char kbuf[128] = {};
// 定义三个指针指向映射后的虚拟内存
unsigned int *vir_moder;
unsigned int *vir_odr;
 
unsigned int *vir_moder2;
unsigned int *vir_odr2;
 
unsigned int *vir_moder3;
unsigned int *vir_odr3;
 
unsigned int *vir_rcc;
// 封装操作方法
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__);
    int 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__);
    int ret;
    ret = copy_from_user(kbuf, ubuf, size);
    if (ret)
    {
        printk("copy_from_user filed\n");
        return -EIO;
    }
 
    if (kbuf[0] == '0') // 关灯
    {
        // 关灯逻辑
        (*vir_odr) &= (~(0X1<<10));//默认关灯
        (*vir_odr2) &= (~(0X1<<10));
        (*vir_odr3) &= (~(0X1<<8));
    }
    else if (kbuf[0] == '1')
    {
        // 开灯逻辑
        (*vir_odr) |= (0X1<<10);
        (*vir_odr2) |= (0X1<<10);
        (*vir_odr3) |= (0X1<<8);
    }
    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对象
struct file_operations fops = {
    .open = mycdev_open,
    .read = mycdev_read,
    .write = mycdev_write,
    .release = mycdev_close,
};
static int __init mycdev_init(void)
{
    // 注册字符设备驱动
    major = register_chrdev(0, "mychrdev", &fops);
    if (major < 0)
    {
        printk("字符设备驱动注册失败\n");
        return major;
    }
    printk("注册字符设备驱动成功major=%d\n", major);
    // 进行寄存器的地址映射
    vir_moder = ioremap(PHY_LED1_MODER, 4);
    if (vir_moder == 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_moder2 == NULL)
    {
        printk("物理内存地址映射失败%d\n", __LINE__);
        return -EFAULT;
    }
    vir_moder3 = ioremap(PHY_LED3_MODER, 4);
    if (vir_moder3 == NULL)
    {
        printk("物理内存地址映射失败%d\n", __LINE__);
        return -EFAULT;
    }
    vir_odr = ioremap(PHY_LED1_ODR, 4);
    if (vir_odr == 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_odr3 = ioremap(PHY_LED3_ODR, 4);
    if (vir_odr3 == 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");
    //LED1寄存器初始化
    (*vir_rcc) |= (0X1<<4);//GPIOE控制器时钟使能
    (*vir_moder) &= (~(0X3<<20));//MODER[21:20]->00
    (*vir_moder) |= (0X1<<20);//MODER[21:20]->01
    (*vir_odr) &= (~(0X1<<10));//默认关灯
    //LED2寄存器初始化
    (*vir_rcc) |= (0X1<<5);//GPIOE控制器时钟使能
    (*vir_moder2) &= (~(0X3<<20));//MODER[21:20]->00
    (*vir_moder2) |= (0X1<<20);//MODER[21:20]->01
    (*vir_odr2) &= (~(0X1<<10));//默认关灯
    //LED3寄存器初始化
    (*vir_rcc) |= (0X1<<4);//GPIOE控制器时钟使能
    (*vir_moder3) &= (~(0X3<<16));//MODER[17:16]->00
    (*vir_moder3) |= (0X1<<16);//MODER[17:16]->01
    (*vir_odr3) &= (~(0X1<<8));//默认关灯
    return 0;
}
static void __exit mycdev_exit(void)
{
    //取消内存映射
    iounmap(vir_moder);
    iounmap(vir_odr);
    iounmap(vir_moder2);
    iounmap(vir_odr2);
    iounmap(vir_moder3);
    iounmap(vir_odr3);
    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");

text.c

#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");
        return -1;
    }
    printf("打开设备文件成功\n");
    while (1)
    {
        printf("请输入要进行的操作:0(关灯)1(开灯)>");
        fgets(buf, sizeof(buf), stdin); // 在终端读一个字符串
        buf[strlen(buf) - 1] = '\0';
        write(fd, buf, sizeof(buf)); // 将数据传递给内核
    }
    close(fd);
    return 0;
}

head.h

#ifndef __HEAD_H__
#define __HEAD_H__
#define PHY_LED1_MODER 0X50006000
#define PHY_LED1_ODR   0X50006014
#define PHY_RCC        0X50000A28
 
#define PHY_LED2_MODER 0X50007000
#define PHY_LED2_ODR   0X50007014
 
#define PHY_LED3_MODER 0X50006000
#define PHY_LED3_ODR   0X50006014
 
 
#endif

makefile

modname ?= demo
arch ?= arm
ifeq ($(arch),arm)
#KERNELDIR保存开发板内核源码路径
	KERNELDIR := /home/ubuntu/linux-5.10.61/
else
#保存UBUNTU内核
KERNELDIR :=/lib/modules/$(shell uname -r)/build
#KERNELDIR :=/lib/modules/5.3.0-28-generic/build
endif
 
#PWD保存当前内核模块的路径
PWD := $(shell pwd)
#PWD := /home/ubuntu/qudong/day1
all:
#make modules是模块化编译命令
#make -C $(KERNLEDIR）执行make之前先切换到KERNELDIR对应的路径
#M=$(PWD)表示进行模块化编译的路径是PwD保存的路径
	make -C $(KERNELDIR) M=$(PWD) modules
clean:
#编译清除
	make -C $(KERNELDIR) M=$(PWD) clean
#将obj-m保存的文件单独链接为内核模块
obj-m := $(modname).o