topic Re: Correct device settings for display Tianma nl10276bc13-01c in i.MX Processors

Correct device settings for display Tianma nl10276bc13-01c

adrocohen — Thu, 02 Apr 2020 16:31:08 GMT

Hello all!

I want to create correct device tree for Tianma nl10276bc13-01c with BSP for imx6qp (TQMa6x platform) .

I've built OS image and currently try to use imx6qdl-mba6-lvds-tm070jvhg33.dtsi (in attach) from kernel-4.14, which is compatible with other Tianma display:

/*
* Copyright 2018 Markus Niebel, TQ Systems GmbH
*
* The code contained herein is licensed under the GNU General Public
* License. You may obtain a copy of the GNU General Public License
* Version 2 or later at the following locations:
*
* http://www.opensource.org/licenses/gpl-license.html
* http://www.gnu.org/copyleft/gpl.html
*/
/ {
backlight_ldb: backlight@0 {
compatible = "pwm-backlight";
pinctrl-names = "default";
pinctrl-0 = <&pinctrl_backlight>;
pwms = <&pwm1 0 62500>;
brightness-levels = <0 16 32 64 96 128 160 192 224 255>;
default-brightness-level = <5>;
power-supply = <&reg_mba6_3p3v>;
enable-gpios = <&gpio4 5 GPIO_ACTIVE_HIGH>;
status = "okay";
};
panel-lvds0 {
compatible = "tianma,tm070jvhg33";
backlight = <&backlight_ldb>;
power-supply = <&reg_mba6_3p3v>;
status = "okay";
port {
panel_in_lvds0: endpoint {
remote-endpoint = <&lvds0_out>;
};
};
};
};
&ldb {
status = "okay";
lvds-channel@0 {
fsl,data-mapping = "spwg";
fsl,data-width = <24>;
status = "okay";
port@4 {
reg = <4>;
lvds0_out: endpoint {
remote-endpoint = <&panel_in_lvds0>;
};
};
};
lvds-channel@1 {
status = "disabled";
};
};
&iomuxc {
imx6qdl-mba6 {
pinctrl_backlight: backlightgrp {
fsl,pins = <
/* LCD.BLT_EN */
MX6QDL_PAD_GPIO_19__GPIO4_IO05 0x0001b099
>;
};
};
};

But my display has different characteristics (other size, other resolution...), so I see some poor quality when run some qt-examples (see examples below).

I cannot get what's the problem, is it related to wrong resolution or wrong color depth? And what should I change in device tree for correct display working?

Re: Correct device settings for display Tianma nl10276bc13-01c

igorpadykov — Fri, 03 Apr 2020 00:11:07 GMT

Hi Maksim

for custom lcd timings one can look at documentation:

fsl,imx-fb.txt - Documentation/devicetree/bindings/video/fsl,imx-fb.txt - Linux source code (v4.0) - Bootlin

Adding a custom display

https://community.nxp.com/thread/355690

Best regards
igor
-----------------------------------------------------------------------------------------------------------------------
Note: If this post answers your question, please click the Correct Answer button. Thank you!
-----------------------------------------------------------------------------------------------------------------------

Re: Correct device settings for display Tianma nl10276bc13-01c

adrocohen — Fri, 03 Apr 2020 07:04:20 GMT

Thank you for such useful links, I will try to get into it and try to build my device tree.

So, bad image quality is related to wrong timings, right?

Re: Correct device settings for display Tianma nl10276bc13-01c

adrocohen — Mon, 06 Apr 2020 06:38:42 GMT

I've found wrong option in configuration after consulting with a electronics specialist, it was 'data-mapping', the right option for color map had to be 'jeida'.

Anyway, thanks.