原创 LCD BackLight Control for utulinux 2440 LCD 背光控制

LCD BackLight Control for utulinux 2440 LCD 背光控制          

          注解：borlittle

仅供学习参考，源代码版权归原著者所有

/*

 *    Copyright (C) 2007 UTULinux

 *

 *  LCD BackLight Control V0.01

 *  LCD 背光控制

 *  This file is subject to the terms and conditions of the GNU General Public

 *  License. See the file COPYING in the main directory of this archive for

 *  more details.

 *

 */

 */

#include <stdlib.h>                   /*标准库函数头文件*/

#include <fcntl.h>                    /*文件控制操作头文件*/

#include <string.h>                   /*字符操作头文件*/

#include <sys/ioctl.h>                /*特殊I/O控制函数ioctl头文件，在系统目录的sys目录下*/

#include <linux/fb.h>                 /*FrameBuffer设备驱动头文件位于ARM\arm-linux\include\linux\fb.h*/

int main(int argc, char** argv)       /*带参数主函数*/

{

    if ( argc == 1 )                  /*提供shell操作提示*/     

       {

              printf("Useage:fbtools on\n");

              printf("       fbtools off\n");

              return 1;

       }

       int fb = open("/dev/fb0", O_RDWR);   /*打开设备*/

       if( fb < 0 ) 

       {

              printf("Cann't open /dev/fb0\n");  /*打开失败，提示错误*/

              return 1;

       }

    int on = 0;

    if( strcmp( argv[1], "on" ) == 0 )   /*处理控制数据*/

        on = 4;

    else if( strcmp( argv[1], "off" ) == 0 )

        on = 2;

       ioctl(fb, FBIOBLANK, on );  /*控制I/O设备点亮/关闭背光*/

       close(fb);                  /*关闭退出*/

}