I.MX6 Android backlight modify by C demo-白红宇

I.MX6 Android backlight modify by C demo

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发布时间：2019-06-22

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/************************************************************************** *             I.MX6 Android backlight modify by C demo * 说明： *     因为一些特殊情况，需要添加一个这个简单的控制程序来控制android背光 * 亮度，个人感觉是没有必要的，但是应要求还是加上。 * *                                      2016-5-14 深圳 南山平山村 曾剑锋 *************************************************************************/#include 
     
        #include 
      
         #include 
       
          #include 
        
           #include 
         
            #include 
          
            #include 
           
             #include 
            
             #include 
             
               #define BACKLIGHT0_PATH "/sys/class/backlight/pwm-backlight.0/brightness"#define BACKLIGHT1_PATH "/sys/class/backlight/pwm-backlight.1/brightness"//#define BACKLIGHT0_PATH "brightness0"//#define BACKLIGHT1_PATH "brightness1"int help ( int argc );int isDigitalStr(char *str);int file_exists(char *filename);void writeStringToFile(char *filePath, char *string);int main(int argc, char **argv) { int bl0 = 0; int bl1 = 0; if ( help( argc ) != 0) return -1; if ( !isDigitalStr(argv[1]) ) { printf("Please give a numeric string.\n"); return -1; } writeStringToFile(BACKLIGHT0_PATH, argv[1]); writeStringToFile(BACKLIGHT1_PATH, argv[1]);}void writeStringToFile(char *filePath, char *string) { int fd = 0; if ( file_exists(filePath) ) { fd = open(filePath, O_RDWR); ftruncate(fd, 0); write(fd, string, strlen(string)); close(fd); }}int isDigitalStr(char *str){ int len = strlen(str); char *s = str; int i = 0; while( '0' <= *s && *s <= '9' && i < len){ s++; i++; } if(i == len) return 1; else return 0; }int file_exists(char *filename) { if (access(filename, F_OK) == 0) { return 1; } else { printf("%s is not exist.\n", filename); return 0; }}int help( int argc ) { if ( argc != 2 ) { printf ( "USAGE:\n" ); printf ( " backlight 
              
               \n" ); printf ( " example:\n" ); printf ( " backlight 0\n" ); return -1; } return 0;}