u-boot in i.MX93 EVK and changing device tree blob (dtb)

[bitspirate]

Hi NXP Staff,

My goal was to modify the device tree that the kernel starts to activate the LVDS panel.

Now, I tried several ways and I fail to understand what is going on in u-boot-imx. Using devtool shows that only imx93-11x11-evk.dts is available, however I cannot find where the other dtbs are built.

Trying to set a different dts will obviously fail, since u-boot cannot find it. Unfortunately I am failing at figuring out where the other dtbs are built (in my deploy dir there are plenty of other dtbs).

Initially, I thought it would just require to modify any of the following variables:

UBOOT_DTB_NAME = "imx93-11x11-evk-boe-wxga-lvds-panel.dtb"

KERNEL_DEVICETREE_BASENAME = "imx93-11x11-evk-boe-wxga-lvds-panel"

This does not work, either by bbappend or local.conf. The result is always imx93-11x11-evk. Where or how is the right way/place to modify the device tree that is passed to the kernel?

Thanks

[brian14]

Hi @bitspirate, 

Thank you for contacting NXP Support. 

Here is a link to an article that you could find especially useful to properly compile your device tree:
How to use Devshell to compile device tree files. - NXP Community

To set the device tree on your board you will need to edit the variable environment for device tree on U-Boot using the following commands:

1. Use fatls <interface> <device[:partition]> [<directory>]

fatls mmc 1:1
(Device 1 : Partition 1)

With this command, we will be able to list device tree files.

=> fatls mmc 1:1

2. Select your device tree "imx93-lvds.dtb" and use the command editenv fdtfile

=> editenv fdtfile
Output example
edit: imx93-lvds.dtb

3. In edit command line put the selected device tree .dtb
4. Use saveenv command to save environment and continue with the boot process.

I hope this information will be helpful. 

Have a great day!