RK lvds TF卡修改屏参

 https://blog.csdn.net/jiangdou88/article/details/49129057

https://blog.csdn.net/MrDongShiYi/article/details/97395945

https://blog.csdn.net/u014770862/article/details/76274951

一.RK3288 android5.1 屏参

screen-type = 3;-------------------------------------------屏幕类型
lvds-format = 0;-------------------------------------------LVDS 信号的分配方式
out-face    =33 ;------------------------------------------表示屏幕采用多少位的接线方式
color-mode = 0;
clock-frequency = 175000000;-------------------------------屏幕的点时钟
hactive = 1920;--------------------------------------------屏幕横向分辨率 Horizontal Valid
vactive = 1080;--------------------------------------------屏幕纵向分辨率 Vertical Valid
hback-porch = 100;-----------------------------------------左边界   Horizontal Back Porch
hfront-porch = 18;-----------------------------------------右边界   Horizontal Front Porch
vback-porch = 8;-------------------------------------------上边界   Vertical Back Porch
vfront-porch = 6;------------------------------------------下边界   Vertical Front Porch
hsync-len = 10;--------------------------------------------水平同步信号宽度  Horizontal Pulse Width
vsync-len = 2;---------------------------------------------垂直同步信号宽度  Vertical   Pulse Width
hsync-active = 0;
vsync-active = 0;
de-active = 0;
pixelclk-active = 0;
swap-rb = 0;
swap-rg = 0;
swap-gb = 0;
pwm_polarity = 0;------------------------------------------PWM 背光极性

 二.lvds-format

LVDS通道分为Y0、Y1、Y2、Y3，其中Y0对应于上图的Rxin0，Y1对应于上图的Rxin1，Y2和Y3以此类推，一个通道可以传输7bit数据。

 三.

 四.规格书的时序参数表

时钟dclk 频率: clock-frequency = 78 MHZ

水平总周期 = 1606		   
hactive + hback-porch + hfront-porch + hsync-len    = horizontal period(水平总周期)
hback-porch + hfront-porch + hsync-len = horizontal period - hactive =	1606 - 1366	
148			  88     		 44		   = 240 
									   
垂直总周期 = 808
vactive + vback-porch + vfront-porch + vsync-active = vertical period(垂直总周期)
vback-porch + vfront-porch + vsync-active = vertical period - vactive =	808 - 768
30			  5			  	 5			  = 40

五. RK3368 屏参说明

screen-type = 1;----------------->1为LVDS  9为EDP
lvds-format = 0;----------------->无效项，不需要调整
out-face    =33 ;----------------->24bit 默认不修改
color-mode = 0;----------------->无效项，不需要调整
clock-frequency = 134;----------------->频率，参考规格书调整
hactive = 1920;----------------->分辨率H
vactive = 1080;----------------->分辨率V
hback-porch = 100;----------------->左边界	
hfront-porch = 18;----------------->右边界
vback-porch = 8;----------------->上边界
vfront-porch = 6;----------------->下边界
hsync-len = 10;----------------->水平同步信号宽度 
vsync-len = 2;----------------->垂直同步信号宽度 
hsync-active = 0;----------------->行极性
vsync-active = 0;----------------->场极性
de-active = 0;----------------->DE模式
pixelclk-active = 0;----------------->时钟极性
swap-rb = 0;----------------->默认不修改
swap-rg = 0;----------------->默认不修改
swap-gb = 0;----------------->默认不修改
pwm_polarity = 0;----------------->屏背光极性，调节亮度相反可修改这项0/1
lvds_mode= 0;----------------->LVDS模式 0/1
lvds_68bit= 0;----------------->LVDS 6/8模式 0/1
lvds_map= 0;----------------->LVDS map 0/1 花屏可修改此项
lvds_ddrn= 1;----------------->LVDS ddrn 0/1 无显示可先调此项

　

六.PWM

　

计算PWM值

Android7.1 默认pwm为1000000HZ
1K=1000HZ
根据上图知道 最小200HZ,即0.2k
1000000/0.2=5000000HZ 则dts配pwms = <&pwm0 0 5000000 0>;