驱动 - 20230816

练习

1.编写LED灯的驱动，可以控制三个灯，应用程序中编写控制灯的逻辑，要使用自动创建设备节点机制

驱动头文件 ledHead.h

#ifndef __HEAD_H__
#define __HEAD_H__

#define PHY_GPIOE_MODER 0X50006000
#define PHY_GPIOE_ODR 0X50006014
#define PHY_RCC 0X50000A28

#define PHY_GPIOF_MODER 0X50007000
#define PHY_GPIOF_ODR 0X50007014

#endif

驱动demo.c

#include <linux/init.h>
#include <linux/module.h>
#include <linux/fs.h>
#include <linux/uaccess.h>
#include <linux/io.h>
#include <linux/device.h>
#include "ledHead.h"

int major;
char buf[128];

unsigned int *vir_gpioe_moder;
unsigned int *vir_gpioe_odr;
unsigned int *vir_gpiof_moder;
unsigned int *vir_gpiof_odr;
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) {
    
    int ret = copy_to_user(ubuf, buf, size);
    if (ret) {
        printk("内核read失败: %d \n", ret);
    }
    printk("%s:%s:%d\n",__FILE__,__func__,__LINE__);
    return 0;
}

ssize_t mycdev_write(struct file *file, const char *ubuf, size_t size, loff_t *lof) {
    int ret = copy_from_user(buf, ubuf, size);
    if (ret) {
        printk("内核write失败: %d \n", ret);
		return ret;
    }
	
    
	if (buf[0] == '1' && buf[1] == '1') {
		//LED1开灯
        (*vir_gpioe_odr) |= (0x1 << 10);
	} else if (buf[0] == '1' && buf[1] == '0') {
		//LED1关灯
		(*vir_gpioe_odr) &= (~(0x1 << 10));
	} else if (buf[0] == '2' && buf[1] == '1') {
        //LED2开灯
		(*vir_gpiof_odr) |= (0x1 << 10);
	} else if (buf[0] == '2' && buf[1] == '0') {
		//LED2关灯
		(*vir_gpiof_odr) &= (~(0x1 << 10));
	} else if (buf[0] == '3' && buf[1] == '1') {
		//LED1开灯
		(*vir_gpioe_odr) |= (0x1 << 8);
	} else if (buf[0] == '3' && buf[1] == '0') {
		//LED1关灯
		(*vir_gpioe_odr) &= (~(0x1 << 8));
	}

    return 0;
}

int mycdev_close(struct inode *inode, struct file *file) {
    printk("%s:%s:%d\n",__FILE__,__func__,__LINE__);
    return 0;
}

struct file_operations fops = {
    .open = mycdev_open,
    .read = mycdev_read,
    .write = mycdev_write,
    .release = mycdev_close,
};

static int __init mycdev_init(void) {
    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);

    /**
     * 向上提交目录信息
    */
    cls = class_create(THIS_MODULE, "mycdev");
    if (IS_ERR(cls)) {
        printk("向上提交目标信息失败\n");
        return -PTR_ERR(cls);
    }
    printk("向上提交目录信息成功\n");

    //向上提交设备信息
    int i;
    for (i=0; i<3; i++) {
        dev = device_create(cls, NULL, MKDEV(major, i), NULL, "mycdev%d", i);
        if (IS_ERR(dev)) {
            printk("向上提交设备节点失败\n");
            return -PTR_ERR(cls);
        }
    }
    printk("向上提交设备节点信息成功\n");

    /*
    *完成硬件寄存器物理映射
    */
	vir_gpioe_moder = ioremap(PHY_GPIOE_MODER, 4);
	if (vir_gpioe_moder == NULL) {
		printk("物理内存映射失败%d\n", __LINE__);
		return -EFAULT;
	}
	vir_gpioe_odr = ioremap(PHY_GPIOE_ODR, 4);
	if (vir_gpioe_odr == NULL) {
		printk("物理内存映射失败%d\n", __LINE__);
		return -EFAULT;
	}
    vir_gpiof_moder = ioremap(PHY_GPIOF_MODER, 4);
	if (vir_gpiof_moder == NULL) {
		printk("物理内存映射失败%d\n", __LINE__);
		return -EFAULT;
	}
    vir_gpiof_odr = ioremap(PHY_GPIOF_ODR, 4);
	if (vir_gpiof_odr == NULL) {
		printk("物理内存映射失败%d\n", __LINE__);
		return -EFAULT;
	}
	vir_rcc = ioremap(PHY_RCC, 4);
	if (vir_rcc == NULL) {
		printk("物理内存映射失败%d\n", __LINE__);
		return -EFAULT;
	}
	printk("物理内存映射成功\n");
	//硬件寄存器初始化
    //设置LED1
	(*vir_gpioe_moder) &= (~(0x3 << 20));
	(*vir_gpioe_moder) |= (0x1 << 20);
    //设置LED2
    (*vir_gpiof_moder) &= (~(0x3 << 20));
	(*vir_gpiof_moder) |= (0x1 << 20);
     //设置LED3
    (*vir_gpioe_moder) &= (~(0x3 << 16));
	(*vir_gpioe_moder) |= (0x1 << 16);
	//rcc使能
    (*vir_rcc) |= (0x1 << 4);
    (*vir_rcc) |= (0x1 << 5);
	//默认关灯
    //LED1
	(*vir_gpioe_odr) &= (~(0x1 << 10));
    //LED2
    (*vir_gpiof_odr) &= (~(0x1 << 10));
    //LED3
    (*vir_gpioe_odr) &= (~(0x1 << 8));
    return 0;
}

static void __exit mycdev_exit(void) {
    /**
     * 取消物理内存的映射
    */
	iounmap(vir_gpioe_moder);
	iounmap(vir_gpioe_odr);
    iounmap(vir_gpiof_moder);
	iounmap(vir_gpiof_odr);
	iounmap(vir_rcc);

    /**
     * 销毁设备信息
    */
    int i;
    for (i=0; i<3; i++) {
        device_destroy(cls, MKDEV(major, i));
    }
    /**
     * 销毁目录信息
    */
    class_destroy(cls);

    unregister_chrdev(major, "mychrdev");
}

module_init(mycdev_init);
module_exit(mycdev_exit);

MODULE_LICENSE("GPL");

应用层测试代码 test.c

#include <stdio.h>
#include <sys/types.h>
#include <sys/stat.h>
#include <fcntl.h>
#include <stdlib.h>
#include <unistd.h>
#include <strings.h>
#include <string.h>

int main(int argc, const char *argv[]) {
	char buf[128] = {};
	int fd = open("/dev/mycdev0", O_RDWR);
	if (fd < 0) {
		printf("打开设备文件失败\n");
		return -1;
	}
	int fds[3] = {-1};
	int i;
	for (i=0; i<3; i++) {
		char str[20];
		sprintf(str, "/dev/mycdev%d", i);
		fds[i] = open(str, O_RDWR);
		if (fds[i] < 0) {
			printf("打开设备文件%d失败", i);
			return -1;
		}
	}
	while(1) {
		printf("选择LED1控制方式: 1(开灯), 0(关灯) > \n");

		printf("请输入要实现的逻辑 > \n");
		printf("11: LED1亮");
		printf("10: LED1灭");
		printf("21: LED2亮");
		printf("20: LED2灭");
		printf("31: LED3亮");
		printf("30: LED3灭");
		fgets(buf, sizeof(buf), stdin);
		buf[strlen(buf)-1] = 0;
		if (buf[0] == '1') {
			write(fds[0], buf, sizeof(buf));
		} else if (buf[0] == '2') {
			write(fds[1], buf, sizeof(buf));
		} else if (buf[0] == '3') {
			write(fds[2], buf, sizeof(buf));
		}
	}
	close(fd);
	return 0;
}

结果展示：
请添加图片描述