linux字元裝置驅動-LED驅動

字元裝置驅動-LED驅動

嵌入式Linux版本：linux2.6.24

驅動源碼：

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

//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"    //定義裝置名

#define LED_MAJOR        231       //手動定義主裝置号

#define LED_MINOR        0

//定義要操作的裝置，把每一個led作為結構體的一個成員

static unsigned long led_table [] = {         

        S3C2410_GPB5,

        S3C2410_GPB6,

        S3C2410_GPB8,

        S3C2410_GPB10,

};

//對裝置進行設定，結構體的每一個成員是對對應led的設定

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,

};

//裝置驅動程式中對裝置的I/O通道進行管理的函數，用來實作對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;

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

//            子產品加載函數

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

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，數組不要超長，否則會導緻insmod時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;

}

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

//            子產品解除安裝函數

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

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

測試函數：

#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); //打開裝置檔案

       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); //反轉LED

                     usleep(50000);

              }

              on=!on;

       }

       close(fd);

       return 0;

}

測試：

1.将Makefile和驅動檔案放在同一目錄下，make産生insmod led_driver.ko檔案。

2.開發闆上：insmod led_driver.ko

列印出：Led_Driver insmod success!

  lsmod檢視裝置驅動安裝情況

3.開發闆上：在/mnt/dev下面mknod leds c 231 0 建立裝置節點

4.開發闆上：./led

      LED開始依次閃爍

5.開發闆上：rmmod led_driver.ko解除安裝子產品

 列印出：Led_Driver removed success!