Custom Device Tree LVDS

Technical Support
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1

Hardware/Software: Ixora, imx8, KOE_TX31D200VM0BAA, boot2qt

I am trying to modify my device tree in order to connect my display(data sheet attached) via LVDS. Should I configure the device tree first or install an image first. Does the order even matter? I currently have boot2qt installed.

My .dts file will include the following code, is this correct:

&ldb {

status = “okay”;

lvds-channel@0 {

fsl,data-mapping = “jeida”;

fsl,data-width = <24>;

panel@0 {

compatible = “panel-lvds”;

label = “KOE_TX31D200VM0BAA”;

data-mapping = “jeida-24”;

panel-timing {

clock-frequency = <43248000>;

hactive = <1280>;

vactive = <480>;

hsync-len = <10>;

hfront-porch = <30>;

hback-porch = <40>;

vsync-len = <10>;

vfront-porch = <10>;

vback-porch = <30>;

};

};

};

};

In order to actually modify the code a can’t simply serial into the board and find the .dts file. On my PC I have to download the toolchain and linux kernel which will then allow me to edit the .dts file. I am following the directions from the following link:

Do I need to follow all 4 articles? My belief is that I can skip the U-Boot article and the Linux Kernel articles because they should be preinstalled on the hardware/image. Or do I have to build a new U-boot/kernel and replace the existing ones with the custom ones?

Is there anything else I need to read to finish this?

TX31D200VM0BAA-KOE.pdf (507.7 KB)

2

Hi, I’m the Toradex AI Assistant.

I might make mistakes or occasionally get you wrong. Our support team will step in if needed.

I’d be glad to help you with LVDS display configuration! To provide the most accurate guidance for your specific setup, could you let me know:

  1. Which exact version of the OS/BSP you are running?
  2. For hardware details, please run the tdx-info command on your device and share the output. This will help identify your specific SoM and carrier board configuration. You can find more details about this command at Getting Device Information with Tdx-Info | Toradex Developer Center

Regarding your questions about the development workflow:

Development Order and Approach

The order doesn’t strictly matter, but there are recommended approaches based on your development phase (1):

Development Phase Approach

For faster iteration cycles during development, you can build overlays manually, copy them to the device, and enable them (1). This allows you to test changes quickly without rebuilding entire images.

Device Tree Customization Options

You have two main paths for device tree customization (2):

  1. Modify the base device tree - Create a custom .dts file based on your carrier board’s device tree
  2. Use device tree overlays - Create overlay fragments that modify specific components

Compilation Requirements

For device tree compilation, you will need to set up the build environment (2). The compilation process involves using the Device Tree Compiler (dtc) tool provided with the Linux kernel source code (2).

To compile device trees, you’ll use commands like (2):

$ make DTC_FLAGS="-@" freescale/<custom-device-tree>.dtb

Deployment Options

You can deploy device trees in two ways (2):

  1. To a running device - Copy the compiled .dtb file to /boot directory
  2. To a static image - Integrate into your production image

Once you provide the OS version and hardware details via tdx-info, I can give you more specific guidance on the exact device tree structure and compilation steps for your Apalis iMX8 with LVDS display configuration.

Best regards, Toradex AI Assistant.

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If I answered your question, please tick the “Solution” checkbox.

For follow-up questions to me, please use @ToradexAI in your post.

3

Hey @Waunye11 ,

For development, it’s very normal to get an image onto the device, get setup and then need to make modifications such as add a device tree overlay file to accommodate a particular screen.

Build from source, I would say is not typically the first step to take.

First I would recommend doing our quick start guide to get the SoM + carrier board setup. This will introduce you to our Torizon OS image that I would recommend you start with, and then some tools to help you with application development. And introduction to cloud if that is something your are interested in. Quickstart Guide | Toradex Developer Center

Once you can play around with the hardware/tools. And you want to start to customize the image to include your screen, the tooling to do this is Toizoncore builder. You can read more here.

There is a lot more information, but I think this may be a good place to start. Please follow up with some questions as needed.