LCD/HDMI OUT调试经验（6）------点亮HDMI屏幕

在调试display的经历中，除了一些手持类设备以外其他机器基本都会外接HDMI屏幕，显示原理之前也提过：由模块发出的MIPI信号经过9611或者9611uxc芯片输出HDMI信号最后在屏幕进行显示。这两款芯片的最主要差别是9611uxc最高可以支持到4K60fps 的输出画面而9611是4K30fps。和调试9211的大致步骤完全一样，9611和9611uxc的芯片也是分为添加驱动，上电和配置屏幕，只不过需要具体修改配置屏幕的一些参数。所以请先熟悉9211的调试再阅读本篇文章。

本文基于高通845平台，首先大致讲解上电与添加驱动操作，配置屏幕方面在具体调试的过程中1080p与4k的区别会详细介绍。

 

一、阅读材料与上电

首先还是阅读手上的一些材料：芯片数据手册、原理图以及驱动部分代码。这里不再具体介绍，和9211调试的步骤基本一致，而且芯片的上电脚也差不多。这里贴一下9611uxc的原理图与数据手册部分内容

 

 

阅读完芯片手册与原理图下面在驱动进行上电操作，首先还是在设备树配置对应的GPIO：

 接下来添加驱动并且解析对应GPIO再按照时序上电，相关代码就不贴，和9211的是一样的，这一步最主要的还是I2C要调通，后面都相对简单。

 

二、屏幕的配置

这一部分主要讲4k屏幕的配置与1080p的区别，9611uxc最多可以支持4k60 fps的显示，所以向下可以兼容1080p60 fps和720p60 fps，AP的4k MIPI参数配置如下：

（1）AP

/* Copyright (c) 2015-2017, The Linux Foundation. All rights reserved.
 *
 * This program is free software; you can redistribute it and/or modify
 * it under the terms of the GNU General Public License version 2 and
 * only version 2 as published by the Free Software Foundation.
 *
 * This program is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 * GNU General Public License for more details.
 */

&mdss_mdp {
	dsi_lt9611_4k_video: qcom,mdss_dsi_lt9611_4k_video {
		qcom,mdss-dsi-panel-name ="lt9611 video mode dsi panel without DSC";
 		qcom,mdss-dsi-panel-type = "dsi_video_mode";
 		qcom,mdss-dsi-virtual-channel-id = <0>;
 		qcom,mdss-dsi-stream = <0>;
 		qcom,mdss-dsi-bpp = <24>;
 		qcom,mdss-dsi-border-color = <0>;
 		qcom,mdss-dsi-traffic-mode = "burst_mode";
 		qcom,mdss-dsi-bllp-eof-power-mode;
		qcom,mdss-dsi-bllp-power-mode;
 		qcom,mdss-dsi-lane-0-state;
 		qcom,mdss-dsi-lane-1-state;
		qcom,mdss-dsi-lane-2-state;
		qcom,mdss-dsi-lane-3-state;
 		qcom,mdss-dsi-dma-trigger = "trigger_sw";
 		qcom,mdss-dsi-mdp-trigger = "none";
		qcom,mdss-dsi-reset-sequence = <1 200>, <0 200>, <1 200>;
		qcom,mdss-pan-physical-width-dimension = <167>;
		qcom,mdss-pan-physical-height-dimension = <131>;
		qcom,mdss-dsi-tx-eot-append;
		qcom,adjust-timer-wakeup-ms = <1>;
		qcom,mdss-dsi-panel-peak-brightness = <4200000>;
		qcom,mdss-dsi-panel-blackness-level = <3230>;

		qcom,mdss-dsi-display-timings {
			timing@0{
				qcom,mdss-dsi-panel-width = <1920>;
				qcom,mdss-dsi-panel-height = <2160>;
				qcom,mdss-dsi-h-front-porch = <176>;
				qcom,mdss-dsi-h-back-porch = <298>;
				qcom,mdss-dsi-h-pulse-width = <88>;
				qcom,mdss-dsi-h-sync-skew = <0>;
				qcom,mdss-dsi-v-back-porch = <72>;
				qcom,mdss-dsi-v-front-porch = <8>;
				qcom,mdss-dsi-v-pulse-width = <10>;
				qcom,mdss-dsi-h-sync-pulse = <0>;
				qcom,mdss-dsi-panel-framerate = <60>;
				qcom,mdss-dsi-on-command = [
					05 01 00 00 78 00 02 11 00
					05 01 00 00 78 00 02 29 00
					];
				qcom,mdss-dsi-off-command = [05 01 00 00 78 00 02 28 00 
						05 01 00 00 14 00 02 10 00];
				qcom,mdss-dsi-on-command-state = "dsi_lp_mode";
				qcom,mdss-dsi-off-command-state = "dsi_hs_mode";
        qcom,mdss-dsi-force-clock-lane-hs;
			};
		};
 	};
 };

需要注意的是这里的width不是3840而是1920，因为9611uxc的输出是分两路port，也就是可以理解为一个4k屏幕是两个小屏拼凑出来的，而小屏的分辨率是1920x2160，一路port显示左半边一路显示右半边，当驱动来加载这里的参数时并且配置为两路port后会自动拼接，在这里只需要这样配置就可以了。

下面是配置背光以及kernel屏幕选择的设备树：

背光添加：

&dsi_lt9611_1080p_video {
	qcom,panel-supply-entries = <&dsi_panel_pwr_supply>;
	qcom,mdss-dsi-bl-pmic-control-type = "bl_ctrl_wled";
	qcom,mdss-dsi-bl-min-level = <1>;
	qcom,mdss-dsi-bl-max-level = <4095>;
	qcom,mdss-dsi-mode-sel-gpio-state = "dual_port";
	qcom,panel-mode-gpio = <&tlmm 99 0>;
	qcom,platform-reset-gpio = <&tlmm 100 0>;
};

&dsi_lt9611_4k_video {
	qcom,panel-supply-entries = <&dsi_panel_pwr_supply>;
	qcom,mdss-dsi-bl-pmic-control-type = "bl_ctrl_wled";
	qcom,mdss-dsi-bl-min-level = <1>;
	qcom,mdss-dsi-bl-max-level = <4095>;
	qcom,mdss-dsi-mode-sel-gpio-state = "dual_port";
	qcom,panel-mode-gpio = <&tlmm 99 0>;
	qcom,platform-reset-gpio = <&tlmm 100 0>;
};


&dsi_lt9611_720p_video {
	qcom,panel-supply-entries = <&dsi_panel_pwr_supply>;
	qcom,mdss-dsi-bl-pmic-control-type = "bl_ctrl_wled";
	qcom,mdss-dsi-bl-min-level = <1>;
	qcom,mdss-dsi-bl-max-level = <4095>;
	qcom,mdss-dsi-mode-sel-gpio-state = "dual_port";
	qcom,panel-mode-gpio = <&tlmm 99 0>;
	qcom,platform-reset-gpio = <&tlmm 100 0>;
};

 这边的reset脚和panel mode脚需要根据平台配置，另外在使用9611uxc时sel gpio state需要配置为dual_port代表两路port输出。

设置可选择显示的屏幕以及时钟pin脚等参数：

dsi_lt9611_1080p_video_display: qcom,dsi-display@21 {
		compatible = "qcom,dsi-display";
		label = "dsi_lt9611_1080p_video_display";
		qcom,display-type = "primary";

		qcom,dsi-ctrl = <&mdss_dsi0 &mdss_dsi1>;
		qcom,dsi-phy = <&mdss_dsi_phy0 &mdss_dsi_phy1>;
		clocks = <&mdss_dsi0_pll BYTECLK_MUX_0_CLK>,
			<&mdss_dsi0_pll PCLK_MUX_0_CLK>;
		clock-names = "mux_byte_clk", "mux_pixel_clk";

		pinctrl-names = "panel_active", "panel_suspend";
		pinctrl-0 = <&sde_dsi_active &sde_te_active>;
		pinctrl-1 = <&sde_dsi_suspend &sde_te_suspend>;
		qcom,platform-te-gpio = <&tlmm 10 0>;
		qcom,platform-reset-gpio = <&tlmm 6 0>;
		qcom,panel-mode-gpio = <&tlmm 52 0>;

		qcom,dsi-panel = <&dsi_lt9611_1080p_video>;
		vddio-supply = <&pm8998_l14>;
		lab-supply = <&lab_regulator>;
		ibb-supply = <&ibb_regulator>;
	};

	dsi_lt9611_4k_video_display: qcom,dsi-display@22 {
		compatible = "qcom,dsi-display";
		label = "dsi_lt9611_4k_video_display";
		qcom,display-type = "primary";

		qcom,dsi-ctrl = <&mdss_dsi0 &mdss_dsi1>;
		qcom,dsi-phy = <&mdss_dsi_phy0 &mdss_dsi_phy1>;
		clocks = <&mdss_dsi0_pll BYTECLK_MUX_0_CLK>,
			<&mdss_dsi0_pll PCLK_MUX_0_CLK>;
		clock-names = "mux_byte_clk", "mux_pixel_clk";

		pinctrl-names = "panel_active", "panel_suspend";
		pinctrl-0 = <&sde_dsi_active &sde_te_active>;
		pinctrl-1 = <&sde_dsi_suspend &sde_te_suspend>;
		qcom,platform-te-gpio = <&tlmm 10 0>;
		qcom,platform-reset-gpio = <&tlmm 6 0>;
		qcom,panel-mode-gpio = <&tlmm 52 0>;

		qcom,dsi-panel = <&dsi_lt9611_4k_video>;
		vddio-supply = <&pm8998_l14>;
		lab-supply = <&lab_regulator>;
		ibb-supply = <&ibb_regulator>;
	};


	dsi_lt9611_720p_video_display: qcom,dsi-display@20 {
		compatible = "qcom,dsi-display";
		label = "dsi_lt9611_720p_video_display";
		qcom,display-type = "primary";

		qcom,dsi-ctrl = <&mdss_dsi0 &mdss_dsi1>;
		qcom,dsi-phy = <&mdss_dsi_phy0 &mdss_dsi_phy1>;
		clocks = <&mdss_dsi0_pll BYTECLK_MUX_0_CLK>,
			<&mdss_dsi0_pll PCLK_MUX_0_CLK>;
		clock-names = "mux_byte_clk", "mux_pixel_clk";

		pinctrl-names = "panel_active", "panel_suspend";
		pinctrl-0 = <&sde_dsi_active &sde_te_active>;
		pinctrl-1 = <&sde_dsi_suspend &sde_te_suspend>;
		qcom,platform-te-gpio = <&tlmm 10 0>;
		qcom,platform-reset-gpio = <&tlmm 6 0>;
		qcom,panel-mode-gpio = <&tlmm 52 0>;

		qcom,dsi-panel = <&dsi_lt9611_720p_video>;
		vddio-supply = <&pm8998_l14>;
		lab-supply = <&lab_regulator>;
		ibb-supply = <&ibb_regulator>;
	};

计算时序并配置：

&dsi_lt9611_1080p_video {
	qcom,mdss-dsi-t-clk-post = <0x0A>;  //1920x2160 60 4lane
	qcom,mdss-dsi-t-clk-pre = <0x20>;   //1920x2160 60 4lane
	qcom,mdss-dsi-display-timings {
		timing@0{
			qcom,mdss-dsi-panel-phy-timings = [00 13 04 04 1F 1E 05    
				05 03 02 04 00];
			qcom,display-topology = <2 0 2>,<1 0 2>;
			qcom,default-topology-index = <0>;
		};
	};
};


&dsi_lt9611_720p_video {
	qcom,mdss-dsi-t-clk-post = <0x09>;  //640x720 60 4lane
	qcom,mdss-dsi-t-clk-pre = <0x17>;
	qcom,mdss-dsi-display-timings {
		timing@0{
			qcom,mdss-dsi-panel-phy-timings = [00 0c 03 03 1d 1d 03    
				03 01 02 04 00];
			qcom,display-topology = <2 0 2>,<1 0 2>;
			qcom,default-topology-index = <0>;
		};
	};
};


&dsi_lt9611_4k_video {
	qcom,mdss-dsi-t-clk-post = <0x15>;  //1920x2160 60 4lane
	qcom,mdss-dsi-t-clk-pre = <0x30>;   //1920x2160 60 4lane
	qcom,mdss-dsi-display-timings {
		timing@0{
			qcom,mdss-dsi-panel-phy-timings = [00 3E 11 11 30 2C 11    
				11 0C 02 04 00];
			qcom,display-topology = <2 2 2>;
			qcom,default-topology-index = <0>;
		};
	};
};

这一部分需要注意1080p与4k配置的区别，如分辨率1080p是正常配置而4k则需要将宽度减小一半并且时序也是用缩小的分辨率来计算。还需要注意display-topology这一项参数，官方文档给出的配置为4k应设置<2 2 2>.

如果需要添加pinctrl，先在pinctrl文件添加对应GPIO再引用。

 

（2）BP

BP的配置很简单，在MDDPlatformLib.c文件中添加三个不同分辨率的xml常量，再在.h文件添加你想要显示的三块屏幕，最后在逻辑代码中修改选择显示的屏幕即可，参考9211修改或者之前的提交记录即可。

 

三、总结

本文大概介绍了9611与9611uxc的调试办法，很多细节在点亮LCD与LVDS的时候都已经写过了，如果有比较模糊的地方可以参考LVDS与LCD的调试文档，关于I2C的权限问题在GPIO的文档中也提过，但是在此之前的文章中没有具体介绍如何调试I2C与定位屏幕不显示的问题，在下一篇中将根据个人调试经验详细介绍I2C与屏幕不显示的调试办法。