linux字符设备驱动-LED驱动

字符设备驱动-LED驱动

嵌入式Linux版本：linux2.6.24

驱动源码：

//=================================================

//version: linux2.6.24

//led_pin:GB5/GB6/GB8/GB10

//=================================================

#include <linux/kernel.h>

#include <linux/module.h>

#include <linux/init.h>

#include <linux/fs.h>

#include <linux/types.h>

#include <linux/slab.h>

#include <linux/errno.h>

#include <linux/ioctl.h>

#include <linux/cdev.h>

#include <linux/device.h>

#include <asm/irq.h>

#include <asm/arch/regs-gpio.h>

#include <asm/hardware.h>

#define DEVICE_NAME      "leds"    //定义设备名

#define LED_MAJOR        231       //手动定义主设备号

#define LED_MINOR        0

//定义要操作的设备，把每一个led作为结构体的一个成员

static unsigned long led_table [] = {         

        S3C2410_GPB5,

        S3C2410_GPB6,

        S3C2410_GPB8,

        S3C2410_GPB10,

};

//对设备进行设置，结构体的每一个成员是对对应led的设置

static unsigned int led_cfg_table [] = {

        S3C2410_GPB5_OUTP,                         //0x01<<10 defined in  refg-gpio.h

        S3C2410_GPB6_OUTP,

        S3C2410_GPB8_OUTP,

        S3C2410_GPB10_OUTP,

};

//设备驱动程序中对设备的I/O通道进行管理的函数，用来实现对led的操作

static int s3c2410_leds_ioctl(struct inode *inode,

       struct file *file, unsigned int cmd, unsigned long arg)

{

    switch(cmd) {

        case 0:

        case 1:

            if (arg > 4)

                return -EINVAL;

            s3c2410_gpio_setpin(led_table[arg], !cmd);

            return 0;

        default:

            return -EINVAL;

    }

}

//

static struct file_operations s3c2410_leds_fops = {

    .owner    =    THIS_MODULE,

    .ioctl    =    s3c2410_leds_ioctl,

};

struct cdev *my_cdev;

struct class *my_class;

//=========================================

//            模块加载函数

//========================================

static int __init s3c2410_leds_init(void)

{

    int err, i;

    int devno = MKDEV(LED_MAJOR, LED_MINOR);//Get device number .

    my_cdev = cdev_alloc();

    cdev_init(my_cdev, &s3c2410_leds_fops);

    my_cdev->owner = THIS_MODULE;

    err = cdev_add(my_cdev, devno, 1);

    if (err != 0)

        printk("led device register failed!\n");

    my_class = class_create(THIS_MODULE, "led_class");

    if(IS_ERR(my_class)) {

        printk("Err: failed in creating class.\n");

        return -1;

     }

    class_device_create(my_class, NULL, devno, NULL, DEVICE_NAME "%d", LED_MINOR );

    //======led端口配置，数组不要超长，否则会导致insmod时segment fault========

    for (i = 0; i < 4; i++) {

        s3c2410_gpio_cfgpin(led_table[i], led_cfg_table[i]);

        s3c2410_gpio_setpin(led_table[i], 1);

    }

    printk("Led_Driver insmod success!\r\n");

    return 0;

}

//========================================

//            模块卸载函数

//=======================================

static void __exit s3c2410_leds_exit(void)

{

    cdev_del(my_cdev);

    class_device_destroy(my_class, MKDEV(LED_MAJOR, LED_MINOR));

    class_destroy(my_class);

    printk("Led_Driver removed success!\r\n");

}

module_init(s3c2410_leds_init);

module_exit(s3c2410_leds_exit);

MODULE_LICENSE("GPL");

工程管理Makefile:

#Makefile for s3c2440_leds.c

obj-m :=led_driver.o

KERNELDIR ?=/home/zhw123/linux-2.6.24

PWD := $(shell pwd)

default:

        $(MAKE) -C $(KERNELDIR) M=$(PWD) modules

clean:

        rm -r led_driver.mod.c led_driver.mod.o led_driver.o Module.symvers

disclean:

        rm -r led_driver.mod.c led_driver.mod.o led_driver.o led_driver.ko Module.symvers

测试函数：

#include "stdio.h"

#include "unistd.h"

#include "sys/types.h"

#include "sys/ioctl.h"

#include "stdlib.h"

#include "termios.h"

#include "sys/stat.h"

#include "fcntl.h"

#include "sys/time.h"

int main(void)

{     

       int on=1;

       int led;

       int fd;

       fd=open("/dev/leds",0); //打开设备文件

       if(fd<0)

       {

              perror("open device leds");

              exit(1);

       }

       printf("leds test show,press ctrl+c to exit \n");

       while(1)

       {

              for(led=0;led<4;led++)

              {

                     ioctl(fd,on,led); //反转LED

                     usleep(50000);

              }

              on=!on;

       }

       close(fd);

       return 0;

}

测试：

1.将Makefile和驱动文件放在同一目录下，make产生insmod led_driver.ko文件。

2.开发板上：insmod led_driver.ko

打印出：Led_Driver insmod success!

  lsmod查看设备驱动安装情况

3.开发板上：在/mnt/dev下面mknod leds c 231 0 创建设备节点

4.开发板上：./led

      LED开始依次闪烁

5.开发板上：rmmod led_driver.ko卸载模块

 打印出：Led_Driver removed success!