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 屏參
screen-type = 3;-------------------------------------------屏幕類型 lvds-format = 0;-------------------------------------------LVDS 信號的分配方式 out-face =33 ;------------------------------------------表示屏幕采用多少位的接線方式 color-mode = 0; clock-frequency = 175000000;-------------------------------屏幕的點時鍾 hactive = 1920;--------------------------------------------屏幕橫向分辨率 Horizontal Valid vactive = 1080;--------------------------------------------屏幕縱向分辨率 Vertical Valid hback-porch = 100;-----------------------------------------左邊界 Horizontal Back Porch hfront-porch = 18;-----------------------------------------右邊界 Horizontal Front Porch vback-porch = 8;-------------------------------------------上邊界 Vertical Back Porch vfront-porch = 6;------------------------------------------下邊界 Vertical Front Porch hsync-len = 10;--------------------------------------------水平同步信號寬度 Horizontal Pulse Width vsync-len = 2;---------------------------------------------垂直同步信號寬度 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 背光極性
二.lvds-format
LVDS通道分為Y0、Y1、Y2、Y3，其中Y0對應於上圖的Rxin0，Y1對應於上圖的Rxin1，Y2和Y3以此類推，一個通道可以傳輸7bit數據。
三.
四.規格書的時序參數表
時鍾dclk 頻率: clock-frequency = 78 MHZ 水平總周期 = 1606 hactive + hback-porch + hfront-porch + hsync-len = horizontal period(水平總周期) hback-porch + hfront-porch + hsync-len = horizontal period - hactive = 1606 - 1366 148 88 44 = 240 垂直總周期 = 808 vactive + vback-porch + vfront-porch + vsync-active = vertical period(垂直總周期) vback-porch + vfront-porch + vsync-active = vertical period - vactive = 808 - 768 30 5 5 = 40
五. RK3368 屏參說明
screen-type = 1;----------------->1為LVDS 9為EDP lvds-format = 0;----------------->無效項，不需要調整 out-face =33 ;----------------->24bit 默認不修改 color-mode = 0;----------------->無效項，不需要調整 clock-frequency = 134;----------------->頻率，參考規格書調整 hactive = 1920;----------------->分辨率H vactive = 1080;----------------->分辨率V hback-porch = 100;----------------->左邊界 hfront-porch = 18;----------------->右邊界 vback-porch = 8;----------------->上邊界 vfront-porch = 6;----------------->下邊界 hsync-len = 10;----------------->水平同步信號寬度 vsync-len = 2;----------------->垂直同步信號寬度 hsync-active = 0;----------------->行極性 vsync-active = 0;----------------->場極性 de-active = 0;----------------->DE模式 pixelclk-active = 0;----------------->時鍾極性 swap-rb = 0;----------------->默認不修改 swap-rg = 0;----------------->默認不修改 swap-gb = 0;----------------->默認不修改 pwm_polarity = 0;----------------->屏背光極性，調節亮度相反可修改這項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 花屏可修改此項 lvds_ddrn= 1;----------------->LVDS ddrn 0/1 無顯示可先調此項
六.PWM
計算PWM值
Android7.1 默認pwm為1000000HZ
1K=1000HZ
根據上圖知道 最小200HZ,即0.2k
1000000/0.2=5000000HZ 則dts配pwms = <&pwm0 0 5000000 0>;