可能只能用 ioctl 命令控制背光，但是我测试了一下，并没有什么作用，而且屏幕都黑了。
https://blog.csdn.net/weixin_43772810/article/details/111617402
#include <stdio.h>
#include <sys/types.h>
#include <sys/stat.h>
#include <stdlib.h>
#include <unistd.h>
#include <fcntl.h>
#include <sys/ioctl.h>
//disp驱动部分命令（与背光相关，内核目录：/include/video/sunxi_display2.h)
#define DISP_LCD_SET_BRIGHTNESS 0x102
#define DISP_LCD_GET_BRIGHTNESS 0x103
#define DISP_LCD_BACKLIGHT_ENABLE 0x104
#define DISP_LCD_BACKLIGHT_DISABLE 0x105
#define BRIGHTNESS_MAX 255 //最大亮度
int main(int argc, char *argv[])
{
int fd;
unsigned long args[3]={0};
/*打开disp设备文件*/
fd = open("/dev/disp", O_RDWR, 0);
if(fd < 0)
{
printf("open /dev/disp failed.\n");
return -1;
}
/*打印旧的背光值*/
args[0] = 0; //选择fb0(lcd0)
printf("the old lcd%d brightness is %d\n",\
args[0],ioctl(fd,DISP_LCD_GET_BRIGHTNESS,args));
if(argc != 2)
{
printf("ERROR: the right format: ./app [brightness]\n");
return -1;
}
int brightness = atoi(argv[1]);
if(brightness < 0 || brightness > BRIGHTNESS_MAX)
{
printf("ERROR: the range is 0 to %d\n",BRIGHTNESS_MAX);
return -1;
}
/*参数数组填参*/
args[0] = 0;
args[1] = brightness; //背光值(本人配置里最高为255)
args[2] = 0; //暂时用不到的参数
ioctl(fd,DISP_LCD_SET_BRIGHTNESS,args);
printf("the new lcd%d brightness is %d\n",\
args[0],ioctl(fd,DISP_LCD_GET_BRIGHTNESS,args));
close(fd);
return 0;
}
