BSP (DTS) Editing on yocto

[sojunhan-saram]

Hello, at the moment I am at the stage of creating firmware for a device running and, imx7 using the e-ink screen. As reference boards there is a sabreboard from variscite(VAR-SOM-MX7 Evaluation Kits based on NXP i.MX 7 processor | Variscite ), and V5 (V5 System Board – E Ink Shop ). In addition to them, the layout of their own board ends. Now the task is to create firmware for V5 with a 4.14 linux kernel, for which I took the firmware for the variscite board as a basis, using the yocto builder. The assembly of this firmware starts on the V5 board, but the peripheral does not go through the initialization stage, stopping at the power button stage (logs of successful loading and dangling are attached). Now I am trying to fix the device tree by excluding this button (it is absent on V5) and turning on support for the controller here.
I am sure that my approach is not optimal, but so far I can not find more successful instructions. all that come across are based on a ready-made BSP.
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Actually, I ask you to help with a link to a good instruction on creating or modifying a BSP, not in general terms of 10 pages, but in something more voluminous.
Also - I understand correctly that to solve this problem, in principle, I could just edit the DTS file and rebuild? (http://variwiki.com/index.php?title=Yocto_Build_Release&release=RELEASE_THUD_V1.0_VAR-SOM-MX7#Build_Results I take the distribution kit and instructions here)? And if so, which TPA? Those that I met and contain references to the power button, after changing and executing the command "bitbake linux-variscite -f -c deploy" + uploading files to the SD card did not have any effect (the last log was after this conversion).

[gusarambula]

Hello Sergay Latushev,

Just as a side note, the VAR-SOM board is manufactured and supported by Variscite, so they can better assess you regarding the BSP for their boards.

In general terms of BSP porting there is a BSP Porting Guide available as part of NXP BSPs documentation which may be of help. It’s more than ten pages long but it does not provide a step  by step instruction either so hopefully it may help at least to guide you through the porting process.

https://www.nxp.com/docs/en/user-guide/i.MX_BSP_Porting_Guide_Linux.pdf

There is also a BSP Developer’s Guide from the Yocto Project:

https://www.yoctoproject.org/docs/2.4/bsp-guide/bsp-guide.html

(Make sure that the version corresponds to your Poky version, this link is for Rocko, changes are usually small, but they sometimes are present)

You can edit the DTS and rebuild, but I would first test doing this manually outside of Yocto. The problem is that Yocto is not designed with development in mind so it may not rebuild the device tree binary if it had done it before so that may be why you are not seeing any changes even after editing the device tree sources.

I hope this helps!
Regards,