FL2440驱动添加（4）LED 驱动添加

硬件信息：FL2440板子，s3c2440CPU带四个LED，分别在链接GPB5，GPB6，GPB8，GPB10

内核版本：linux-3.8.0

led驱动代码如下：

值得注意地方地方：

1，定时器的使用：在include/linux/timer.h下定义struct timer_list

struct timer_list {

/*

* All fields that change during normal runtime grouped to the

* same cacheline

*/

struct list_head entry;

unsigned long expires;

struct tvec_base *base;

void (*function)(unsigned long);

unsigned long data;

int slack;

#ifdef CONFIG_TIMER_STATS

int start_pid;

void *start_site;

char start_comm[];

#endif

#ifdef CONFIG_LOCKDEP

struct lockdep_map lockdep_map;

#endif

};

详细参考：linux-2.4.18内核定时器的使用

2，设置GPIO函数有中，linux-3.8.0和linux-3.0.0有所不同，具体可以参考Documentation/arm/Samsung-S3C24XX/GPIO.txt中的说明,只列出遇到变换：

	linux-3.8.0	linux-3.0.0	参数是否变化
设置GPIO高或低	gpio_set_value（）	s3c2410_gpio_setpin()	不变
设置GPIO工作方式	s3c_gpio_cfgpin()	s3c2410_gpio_cfgpin()	不变

3，Linux核心几个重要跟时间有关的名词或变数，HZ、tick和jiffies之间关系。

HZ：Linux核心每隔固定周期会发出timer interrupt ，HZ是用来定义每一秒有几次timer interrupts，我的机器为100 timer interrupts。

tick:就是HZ的倒数，以秒表示

jiffies：Jiffies为Linux核心变数(32位元变数，unsigned long)，它被用来纪录系统自开机以来的tick数，每发生一次timer interrupt，Jiffies变数会被加一。

4，设备节点自动创建函数：class_create()和device_create（）

从linux 内核2.6.24的某个版本之后，devfs不复存在，udev成为devfs的替代。udev处于应用层;加入对udev的支持很简单，以一个字符设备驱动led为例，在驱动初始化的代码里调用class_create为该设备创建一个class，再为每个设备调用 device_create创建对应的设备。

大致用法如下：
struct class *class = class_create(THIS_MODULE, “led”);
device_create(class, NULL, MKDEV(major_num, 0), NULL, “led”);
这样的module被加载时，udev daemon就会自动在/dev下创建led设备文件。

led驱动代码plat_led.c：

/*********************************************************************************
* Copyright: (C) 2011 Guo Wenxue<guowenxue@gmail.com>

* All rights reserved.

*

* Filename: s3c_led.c

* Description: This is the common LED driver runs on S3C24XX.

*

* Version: 1.0.0(10/27/2011~)

* Author: Guo Wenxue <guowenxue@gmail.com>

* ChangeLog: 1, Release initial version on "10/27/2011 11:39:10 AM"

*

********************************************************************************/

#include "s3c_driver.h"

#define DRV_AUTHOR "Guo Wenxue <guowenxue@gmail.com>"

#define DRV_DESC "S3C24XX LED driver"

/* Driver version*/

#define DRV_MAJOR_VER 1

#define DRV_MINOR_VER 0

#define DRV_REVER_VER 0

#define DEV_NAME DEV_LED_NAME

//#define DEV_MAJOR DEV_LED_MAJOR

#ifndef DEV_MAJOR

#define DEV_MAJOR 0 /* dynamic major by default */

#define TIMER_TIMEOUT 40

static int debug = DISABLE;

static int dev_major = DEV_MAJOR;

static int dev_minor = ;

/* ============================ Platform Device part ===============================*/

/* LED hardware informtation structure*/

struct s3c_led_info

{

unsigned char num; /* The LED number */

unsigned int gpio; /* Which GPIO the LED used */

unsigned char active_level; /* The GPIO pin level(HIGHLEVEL or LOWLEVEL) to turn on or off */

unsigned char status; /* Current LED status: OFF/ON */

unsigned char blink; /* Blink or not */

};

/* The LED platform device private data structure */

struct s3c_led_platform_data

{

struct s3c_led_info *leds;

int nleds;

};

/* LED hardware informtation data*/

static struct s3c_led_info s3c_leds[] = {

[] = {

.num = ,

.gpio = S3C2410_GPB(),

.active_level = LOWLEVEL,

.status = ON,

.blink = DISABLE,

},

[] = {

.num = ,

.gpio = S3C2410_GPB(),

.active_level = LOWLEVEL,

.status = OFF,

.blink = DISABLE,

},

[] = {

.num = ,

.gpio = S3C2410_GPB(),

.active_level = LOWLEVEL,

.status = OFF,

.blink = DISABLE,

},

[] = {

.num = ,

.gpio = S3C2410_GPB(),

.active_level = LOWLEVEL,

.status = OFF,

.blink = DISABLE,

},

};

/* The LED platform device private data */

static struct s3c_led_platform_data s3c_led_data = {

.leds = s3c_leds,

.nleds = ARRAY_SIZE(s3c_leds),

};

struct led_device

{

struct s3c_led_platform_data *data;

struct cdev cdev;

struct class *dev_class;

struct timer_list blink_timer;

} led_device;

static void platform_led_release(struct device * dev)

{

int i;

struct s3c_led_platform_data *pdata = dev->platform_data;

dbg_print("%s():%d\n", __FUNCTION__,__LINE__);

/* Turn all LED off */

for(i=; i<pdata->nleds; i++)

{

/* for linux-3.8.0 */

gpio_set_value(pdata->leds[i].gpio, ~pdata->leds[i].active_level);

#if 0

/* for linux-3.0.0 check in s3c2410_gpio_setpin() in Documentation/arm/Samsung-S3C24XX/GPIO.txt*/

s3c2410_gpio_setpin(pdata->leds[i].gpio, ~pdata->leds[i].active_level);

#endif

}

}

static struct platform_device s3c_led_device = {

.name = "s3c_led",

.id = ,

.dev =

{

.platform_data = &s3c_led_data,

.release = platform_led_release,

},

};

/* ===================== led device driver part ===========================*/

void led_timer_handler(unsigned long data)

{

    int  i;

    struct s3c_led_platform_data *pdata = (struct s3c_led_platform_data *)data;

    for(i=; i<pdata->nleds; i++)

    {

        if(ON == pdata->leds[i].status)

        {

              gpio_set_value(pdata->leds[i].gpio, pdata->leds[i].active_level);

        }

        else

        {

              gpio_set_value(pdata->leds[i].gpio, ~pdata->leds[i].active_level);

        }

        if(ENABLE == pdata->leds[i].blink )  /* LED should blink */

        {

            /* Switch status between 0 and 1 to turn LED ON or off */

            pdata->leds[i].status = pdata->leds[i].status ^ 0x01;

        }

        /* time clock */

        mod_timer(&(led_device.blink_timer), jiffies + TIMER_TIMEOUT);

    }

}

static int led_open(struct inode *inode, struct file *file)

{

    struct led_device *pdev ;

    struct s3c_led_platform_data *pdata;

    pdev = container_of(inode->i_cdev, struct led_device, cdev);

    pdata = pdev->data;

    file->private_data = pdata;

    return ;

}

static int led_release(struct inode *inode, struct file *file)

{

    return ;

}

static void print_led_help(void)

{

    printk("Follow is the ioctl() command for LED driver:\n");

    printk("Enable Driver debug command: %u\n", SET_DRV_DEBUG);

    printk("Get Driver verion  command : %u\n", GET_DRV_VER);

    printk("Turn LED on command        : %u\n", LED_ON);

    printk("Turn LED off command       : %u\n", LED_OFF);

    printk("Turn LED blink command     : %u\n", LED_BLINK);

}

/* compatible with kernel version >=2.6.38*/

static long led_ioctl(struct file *file, unsigned int cmd, unsigned long arg)

{

    struct s3c_led_platform_data *pdata = file->private_data;

    switch (cmd)

    {

        case SET_DRV_DEBUG:

            dbg_print("%s driver debug now.\n", DISABLE == arg ? "Disable" : "Enable");

            debug = (==arg) ? DISABLE : ENABLE;

            break;

        case GET_DRV_VER:

            print_version(DRV_VERSION);

            return DRV_VERSION;

        case LED_OFF:

            if(pdata->nleds <= arg)

            {

               printk("LED%ld doesn't exist\n", arg);

               return -ENOTTY;

            }

            pdata->leds[arg].status = OFF;

            pdata->leds[arg].blink = DISABLE;

            break;

        case LED_ON:

              if(pdata->nleds <= arg)

            {

               printk("LED%ld doesn't exist\n", arg);

               return -ENOTTY;

            }

            pdata->leds[arg].status = ON;

            pdata->leds[arg].blink = DISABLE;

            break;

        case LED_BLINK:

            if(pdata->nleds <= arg)

            {

               printk("LED%ld doesn't exist\n", arg);

               return -ENOTTY;

            }

            pdata->leds[arg].blink = ENABLE;

            pdata->leds[arg].status = ON;

            break;

        default:

            dbg_print("%s driver don't support ioctl command=%d\n", DEV_NAME, cmd);

            print_led_help();

            return -EINVAL;

    }

    return ;

}

static struct file_operations led_fops = {

    .owner = THIS_MODULE,

    .open = led_open,

    .release = led_release,

    .unlocked_ioctl = led_ioctl, /* compatible with kernel version >=2.6.38*/

};

static int s3c_led_probe(struct platform_device *dev)

{

    struct s3c_led_platform_data *pdata = dev->dev.platform_data;

    int result = ;

    int i;

    dev_t devno;

    /* Initialize the LED status */

    for(i=; i<pdata->nleds; i++)

    {

         s3c_gpio_cfgpin(pdata->leds[i].gpio, S3C2410_GPIO_OUTPUT);

         if(ON == pdata->leds[i].status)

         {

            gpio_set_value(pdata->leds[i].gpio, pdata->leds[i].active_level);

         }

         else

         {

            gpio_set_value(pdata->leds[i].gpio, ~pdata->leds[i].active_level);

         }

    }

    /*  Alloc the device for driver */

    if ( != dev_major)

    {

        devno = MKDEV(dev_major, dev_minor);

        result = register_chrdev_region(devno, , DEV_NAME);

    }

    else

    {

        result = alloc_chrdev_region(&devno, dev_minor, , DEV_NAME);

        dev_major = MAJOR(devno);

    }

    /* Alloc for device major failure */

    if (result < )

    {

        printk("%s driver can't get major %d\n", DEV_NAME, dev_major);

        return result;

    }

    /* Initialize button structure and register cdev*/

    memset(&led_device, , sizeof(led_device));

    led_device.data = dev->dev.platform_data;

    cdev_init (&(led_device.cdev), &led_fops);

    led_device.cdev.owner  = THIS_MODULE;

    result = cdev_add (&(led_device.cdev), devno , );

    if (result)

    {

        printk (KERN_NOTICE "error %d add %s device", result, DEV_NAME);

        goto ERROR;

    }

    led_device.dev_class = class_create(THIS_MODULE, DEV_NAME);

    if(IS_ERR(led_device.dev_class))

    {

        printk("%s driver create class failture\n",DEV_NAME);

        result =  -ENOMEM;

        goto ERROR;

    }

#if LINUX_VERSION_CODE >= KERNEL_VERSION(2,6,24)

    device_create(led_device.dev_class, NULL, devno, NULL, DEV_NAME);

#else

    device_create(led_device.dev_class, NULL, devno, DEV_NAME);

#endif

    /*  Initial the LED blink timer */

    init_timer(&(led_device.blink_timer));

    led_device.blink_timer.function = led_timer_handler;

    led_device.blink_timer.data = (unsigned long)pdata;  //pass to led_timer_handler()

    led_device.blink_timer.expires  = jiffies + TIMER_TIMEOUT;

    add_timer(&(led_device.blink_timer));

    printk("S3C %s driver version %d.%d.%d initiliazed.\n", DEV_NAME, DRV_MAJOR_VER, DRV_MINOR_VER, DRV_REVER_VER);

    return ;

ERROR:

    printk("S3C %s driver version %d.%d.%d install failure.\n", DEV_NAME, DRV_MAJOR_VER, DRV_MINOR_VER, DRV_REVER_VER);

    cdev_del(&(led_device.cdev));

    unregister_chrdev_region(devno, );

    return result;

}

static int s3c_led_remove(struct platform_device *dev)

{

    dev_t devno = MKDEV(dev_major, dev_minor);

    del_timer(&(led_device.blink_timer));

    cdev_del(&(led_device.cdev));

    device_destroy(led_device.dev_class, devno);

    class_destroy(led_device.dev_class);

    unregister_chrdev_region(devno, );

    printk("S3C %s driver removed\n", DEV_NAME);

    return ;

}

static struct platform_driver s3c_led_driver = {

    .probe      = s3c_led_probe,

    .remove     = s3c_led_remove,

    .driver     = {

        .name       = "s3c_led",

        .owner      = THIS_MODULE,

    },

};

static int __init s3c_led_init(void)

{

   int       ret = ;

   ret = platform_device_register(&s3c_led_device);

   if(ret)

   {

        printk(KERN_ERR "%s:%d: Can't register platform device %d\n", __FUNCTION__,__LINE__, ret);

        goto fail_reg_plat_dev;

   }

   dbg_print("Regist S3C LED Platform Device successfully.\n");

   ret = platform_driver_register(&s3c_led_driver);

   if(ret)

   {

        printk(KERN_ERR "%s:%d: Can't register platform driver %d\n", __FUNCTION__,__LINE__, ret);

        goto fail_reg_plat_drv;

   }

   dbg_print("Regist S3C LED Platform Driver successfully.\n");

   return ;

fail_reg_plat_drv:

   platform_driver_unregister(&s3c_led_driver);

fail_reg_plat_dev:

   return ret;

}

static void s3c_led_exit(void)

{

    dbg_print("%s():%d remove LED platform drvier\n", __FUNCTION__,__LINE__);

    platform_driver_unregister(&s3c_led_driver);

    dbg_print("%s():%d remove LED platform device\n", __FUNCTION__,__LINE__);

    platform_device_unregister(&s3c_led_device);

}

module_init(s3c_led_init);

module_exit(s3c_led_exit);

module_param(debug, int, S_IRUGO);

module_param(dev_major, int, S_IRUGO);

module_param(dev_minor, int, S_IRUGO);

MODULE_AUTHOR(DRV_AUTHOR);

MODULE_DESCRIPTION(DRV_DESC);

MODULE_LICENSE("GPL");

MODULE_ALIAS("platform:S3C24XX_led");

s3c_driver.h头文件:

/********************************************************************************
* Copyright: (C) GuoWenxue <guowenxue@gmail.com>
* All rights reserved.
*
* Filename: s3c_driver.h
* Description: This is the common head file for S3C24XX common driver
*
* Version: 1.0.0(10/29/2011~)
* Author: Guo Wenxue <guowenxue@gmail.com>
* ChangeLog: 1, Release initial version on "10/29/2011 11:27:50 AM"
*
********************************************************************************/

#ifndef __S3C_DRIVER_H
#define __S3C_DRIVER_H

#include <linux/version.h>
#include <linux/kernel.h>
#include <linux/errno.h>
#include <linux/init.h>
#include <linux/slab.h>
#include <linux/module.h>
#include <linux/kref.h>
#include <linux/spinlock.h>
#include <asm/uaccess.h>
#include <linux/mutex.h>
#include <linux/delay.h>

#include <linux/fs.h>
#include <linux/device.h>
#include <linux/i2c.h>
#include <linux/string.h>
#include <linux/bcd.h>
#include <linux/miscdevice.h>
#include <linux/poll.h>
#include <linux/irq.h>
#include <linux/interrupt.h>
#include <linux/sysfs.h>
#include <linux/proc_fs.h>
#include <linux/rtc.h>
#include <linux/spinlock.h>
#include <linux/usb.h>
#include <asm/uaccess.h>
#include <asm/delay.h>
#include <linux/syscalls.h> /* For sys_access*/
#include <linux/platform_device.h>
#include <linux/unistd.h>
#include <linux/tty.h>
#include <linux/tty_flip.h>
#include <linux/serial.h>
#include <linux/serial_core.h>
#include <linux/irq.h>
#include <mach/regs-gpio.h>
#include <linux/gpio.h> //linux-3.8.0的GPIO控制

#if LINUX_VERSION_CODE >= KERNEL_VERSION(2,6,32)
#include <mach/hardware.h>
#include <mach/gpio.h>
#include <asm/irq.h>
#else
#include <asm-arm/irq.h>
#include <asm/arch/gpio.h>
#include <asm/arch/hardware.h>
#endif
#include "plat_ioctl.h"

/* ===========================================================================
* S3C24XX device driver common macro definition
*===========================================================================*/

#define ENPULLUP 1
#define DISPULLUP 0

#define HIGHLEVEL 1
#define LOWLEVEL 0

#define INPUT 1
#define OUTPUT 0

#define OFF 0
#define ON 1

#define ENABLE 1
#define DISABLE 0

#define TRUE 1
#define FALSE 0

/* ===========================================================================
* S3C24XX device driver name and Major number define
*===========================================================================*/

#define DEV_LED_NAME "led"
#define DEV_LED_MAJOR 203

#define DEV_BUTTON_NAME "button"
#define DEV_BUTTON_MAJOR "211"

#define DEV_ADC_NAME "adc"
#define DEV_ADC_MAJOR "212"

/* ***** Bit Operate Define *****/
#define SET_BIT(data, i) ((data) |= (1 << (i))) /* Set the bit "i" in "data" to 1 */
#define CLR_BIT(data, i) ((data) &= ~(1 << (i))) /* Clear the bit "i" in "data" to 0 */
#define NOT_BIT(data, i) ((data) ^= (1 << (i))) /* Inverse the bit "i" in "data" */
#define GET_BIT(data, i) ((data) >> (i) & 1) /* Get the value of bit "i" in "data" */
#define L_SHIFT(data, i) ((data) << (i)) /* Shift "data" left for "i" bit */
#define R_SHIFT(data, i) ((data) >> (i)) /* Shift "data" Right for "i" bit */

/* ===========================================================================
* S3C24XX device driver common function definition
*===========================================================================*/

#define SLEEP(x) {DECLARE_WAIT_QUEUE_HEAD (stSleep); if (10 > x) mdelay ((x * 1000)); \
else wait_event_interruptible_timeout (stSleep, 0, (x / 10));}

#define VERSION_CODE(a,b,c) ( ((a)<<16) + ((b)<<8) + (c))
#define DRV_VERSION VERSION_CODE(DRV_MAJOR_VER, DRV_MINOR_VER, DRV_REVER_VER)
#define MAJOR_VER(a) ((a)>>16&0xFF)
#define MINOR_VER(a) ((a)>>8&0xFF)
#define REVER_VER(a) ((a)&0xFF)

#define dbg_print(format,args...) if(DISABLE!=debug) \
{printk("[kernel] ");printk(format, ##args);}

static inline void print_version(int version)
{
#ifdef __KERNEL__
printk("%d.%d.%d\n", MAJOR_VER(version), MINOR_VER(version), REVER_VER(version));
#else
printf("%d.%d.%d\n", MAJOR_VER(version), MINOR_VER(version), REVER_VER(version));
#endif
}

#endif /* __S3C_DRIVER_H */

plat_ioctl.h头文件:

/*********************************************************************************
* Copyright(c) 2011, Guo Wenxue <guowenxue@gmail.com>
* All ringhts reserved.
*
* Filename: s3c_ioctl.h
* Description: ioctl() cmd argument definition here
*
* ChangLog:
* 1, Version: 1.0.0
* Date: 2011-08-10
* Author: guowenxue <guowenxue@gmail.com>
* Descrtipion: Initial first version
*
*
********************************************************************************/

#ifndef __PLAT_IOCTL_H
#define __PLAT_IOCTL_H

#include <asm/ioctl.h>

/*===========================================================================
* Common ioctl command definition
*===========================================================================*/

#define PLATDRV_MAGIC 0x60

/*===========================================================================
* ioctl command for all the drivers 0x01~0x0F
*===========================================================================*/

/*args is enable or disable*/
#define SET_DRV_DEBUG _IO (PLATDRV_MAGIC, 0x01)
#define GET_DRV_VER _IO (PLATDRV_MAGIC, 0x02)

/*===========================================================================
* ioctl command for few ioctl() cmd driver 0x10~0x2F
*===========================================================================*/

/* LED driver */
#define LED_OFF _IO (PLATDRV_MAGIC, 0x18)
#define LED_ON _IO (PLATDRV_MAGIC, 0x19)
#define LED_BLINK _IO (PLATDRV_MAGIC, 0x1A)
#define ADC_SET_CHANNEL _IO (PLATDRV_MAGIC, 0x1B)

/*===========================================================================
* ioctl command for GPRS driver 0x30~0x4F
*===========================================================================*/
#define GPRS_POWERDOWN _IO (PLATDRV_MAGIC, 0x30)
#define GPRS_POWERON _IO (PLATDRV_MAGIC, 0x31)
#define GPRS_RESET _IO (PLATDRV_MAGIC, 0x32)
#define GPRS_POWERMON _IO (PLATDRV_MAGIC, 0x33)
#define GPRS_CHK_SIMDOOR _IO (PLATDRV_MAGIC, 0x36)
#define GPRS_SET_DTR _IO (PLATDRV_MAGIC, 0x37)
#define GPRS_SET_RTS _IO (PLATDRV_MAGIC, 0x38)
#define GPRS_GET_RING _IO (PLATDRV_MAGIC, 0x39)
#define SET_PWUP_TIME _IO (PLATDRV_MAGIC, 0x3A)
#define SET_PWDOWN_TIME _IO (PLATDRV_MAGIC, 0x3B)
#define SET_RESET_TIME _IO (PLATDRV_MAGIC, 0x3C)
#define GPRS_CHK_MODEL _IO (PLATDRV_MAGIC, 0x3E)

/*===========================================================================
* ioctl command for EEPROM driver 0x50~0x5F
*===========================================================================*/

#define LL_POWEROFF _IO (PLATDRV_MAGIC, 0x50)
#define LL_POWERON _IO (PLATDRV_MAGIC, 0x51)
#define LL_STOP _IO (PLATDRV_MAGIC, 0x52)
#define LL_START _IO (PLATDRV_MAGIC, 0x53)
#define LL_READ _IO (PLATDRV_MAGIC, 0x54)
#define LL_WRITE _IO (PLATDRV_MAGIC, 0x55)
#define LL_DATALOW _IO (PLATDRV_MAGIC, 0x56)
#define LL_ACKNAK _IO (PLATDRV_MAGIC, 0x57)

#endif /* __PLAT_IOCTL_H */

Makefil文件：

ARCH=arm920t
PROJ=fl2440
PWD=$(shell pwd)

ifneq ("${ARCH}", "x86")
CROSS_COMPILE ?= /opt/buildroot-2011.11/${ARCH}/usr/bin/arm-linux- /*指定交叉编译器*/
KERNEL_DIR = ../../kernel/linux-3.8/ /*指定内核路径*/
else
KERNEL_DIR = /lib/modules/$(shell uname -r)/build
endif

obj-m += plat_led.o

all:
make -C $(KERNEL_DIR) SUBDIRS=$(PWD) modules
@make clear

clear:
@rm -f *.o *.cmd *.mod.c
@rm -rf *~ core .depend .tmp_versions Module.symvers modules.order -f
@rm -f .*ko.* *ko.* .*.o.cmd

clean:
rm -f *.ko *.o

led测试程序：
/*********************************************************************************

 *      Copyright:  (C) 2014 zhouguangfeng<zhouguangfeng91@gmail.com>

 *                  All rights reserved.

 *

 *       Filename:  test_plat_led.c

 *    Description:  This file is used to test led platform drvier

 *

 *        Version:  1.0.0(08/25/2014)

 *         Author:  zhouguangfeng <zhouguangfeng91@gmail.com>

 *      ChangeLog:  1, Release initial version on "08/25/2014 04:04:26 PM"

 *

 ********************************************************************************/

#include <stdio.h>

#include <sys/types.h>

#include <sys/stat.h>

#include <fcntl.h>

#include <unistd.h>

#include <sys/ioctl.h>

#define PLATDRV_MAGIC           0x60

#define LED_OFF                     _IO (PLATDRV_MAGIC, 0x18)

#define LED_ON                      _IO (PLATDRV_MAGIC, 0x19)

#define LED_BLINK                   _IO (PLATDRV_MAGIC, 0x1A)

/********************************************************************************

 *  Description:

 *   Input Args:

 *  Output Args:

 * Return Value:

 ********************************************************************************/

int main (int argc, char **argv)

{

    int fd;

    int i;

    fd = open("/dev/led", O_RDWR, );

    if(fd<)

    {

        printf("cannot open.\n");

        goto open_err;

    }

    ioctl(fd, LED_BLINK, );

    ioctl(fd, LED_OFF, );

    ioctl(fd, LED_ON, );

    ioctl(fd, LED_OFF, );

open_err:

    close(fd);

    return ;

} /* ----- End of main() ----- */

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FL2440驱动添加（4）LED 驱动添加

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