lcd屏参

https://blog.csdn.net/qlexcel/article/details/82806884?utm_medium=distribute.pc_relevant.none-task-blog-BlogCommendFromMachineLearnPai2-2.control&depth_1-utm_source=distribute.pc_relevant.none-task-blog-BlogCommendFromMachineLearnPai2-2.control

https://blog.csdn.net/kai_zone/article/details/80341432?utm_medium=distribute.pc_relevant.none-task-blog-baidujs_title-2&spm=1001.2101.3001.4242

https://blog.csdn.net/qq_40177571/article/details/108575036

https://blog.csdn.net/zsj1126/article/details/107078859/

/* include/linux/fb.h */
struct fb_videomode {
const char name; / optional /
u32 refresh; / optional */
u32 xres;
u32 yres;
u32 pixclock;
u32 left_margin;
u32 right_margin;
u32 upper_margin;
u32 lower_margin;
u32 hsync_len;
u32 vsync_len;
u32 sync;
u32 vmode;
u32 flag;
};

refresh :刷新频率（内核中很多例子都赋值为60），标识1s刷新多少张图片
pixclock:每个像素时钟周期的长度，单位是皮秒.此处由硬件配置决定，即LCD的时钟频率

显示一行数据的频率：linefreq=pclk_freq/ (hbp+hfp+hspw+hactive)
显示一帧数据的频率，也为帧率：refresh = pixclock/((hbp+hfp+hspw+hactive)(vfp+vbp+vspw+vactive)
pixclock = refresh * ((hbp+hfp+hspw+hactive)(vfp+vbp+vspw+vactive)

DE模式与HV模式