在设备树中 设备树中的LCD液晶屏修改方法/LCD display timings in device tree

并口 / RGB

接并口屏幕需要参考imx6 datasheet中的以下章节

另外我们的设备树（PD16.1.0）默认未开启 DRDY/DV or DE Data Enable信号。

需要修改 imx6qdl-phytec-mira-peb-av-02.dtsi 文件

diff --git a/arch/arm/boot/dts/imx6qdl-phytec-mira-peb-av-02.dtsi b/arch/arm/boot/dts/imx6qdl-phytec-mira-peb-av-02.dtsi
index 95e450c..66662d1 100644
--- a/arch/arm/boot/dts/imx6qdl-phytec-mira-peb-av-02.dtsi
+++ b/arch/arm/boot/dts/imx6qdl-phytec-mira-peb-av-02.dtsi
@@ -151,7 +151,7 @@
                                MX6QDL_PAD_DI0_PIN2__IPU1_DI0_PIN02        0x10
                                MX6QDL_PAD_DI0_PIN3__IPU1_DI0_PIN03        0x10

-                               MX6QDL_PAD_DI0_PIN15__IPU1_DI0_PIN15  0x1b080
+                               MX6QDL_PAD_DI0_PIN15__IPU1_DI0_PIN15  0x1b0b0

                                MX6QDL_PAD_DISP0_DAT0__IPU1_DISP0_DATA00   0x10
                                MX6QDL_PAD_DISP0_DAT1__IPU1_DISP0_DATA01   0x10


LVDS时钟切换

imx6自带有两路LVDS输出。

imx6的lvds模块可以有两个时钟输入，默认是低频率范围，无法达到37MHz以上。

在dts文件如 imx6q-phytec-mira-rdk-nand.dts 中添加下面的内容，可以切换到高速时钟。

&clks {
     assigned-clocks = <&clks IMX6QDL_CLK_LDB_DI0_SEL>,
               <&clks IMX6QDL_CLK_LDB_DI1_SEL>;
     assigned-clock-parents = <&clks IMX6QDL_CLK_PLL5_VIDEO_DIV>,
               <&clks IMX6QDL_CLK_PLL5_VIDEO_DIV>;
};

双通道LVDS

请参考：

https://github.com/torvalds/linux/commit/b8a559feffb2210344bb11cedc1103311ac41de5#diff-343c12e7de8f2207eccb97b7b30c5022R407

&ldb {
	fsl,dual-channel;
	status = "okay";

 	lvds-channel@0 {
		fsl,data-mapping = "spwg";
		fsl,data-width = <18>;
		status = "okay";

 		display-timings {
			native-mode = <&timing0>;
			timing0: hsd100pxn1 {
				clock-frequency = <65000000>;
				hactive = <1024>;
				vactive = <768>;
				hback-porch = <220>;
				hfront-porch = <40>;
				vback-porch = <21>;
				vfront-porch = <7>;
				hsync-len = <60>;
				vsync-len = <10>;
			};
		};
	};
};

其中lvds的时钟频率是clock-frequency的一半，比如上面这个例子中，是32.5MHz。

如果这里的时钟频率超过56M，也要像之前那样配置LVDS的时钟。

fsl, dual-channel 的说明：https://github.com/torvalds/linux/blob/df0cc57e/Documentation/devicetree/bindings/display/imx/ldb.txt#L40

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