Re: [PATCH v1 0/3] dts: build the DTS from a directory outside the tree

[Vincent Jardin <vjardin@free.fr>]

Hi,

> > > Upstream your hardware support and you won't need external DTs.
> > 
> > Even upstream, how does it solve the Yocto's and Buildroot's related
> > issues ? Both did try to workaround despite they are all upstream.
> Could you apply a patch which contains the custom DT instead ?
> (using SRC_URI:append = " file://0001-your-dt.patch" or similar)

the patch has to be redone, again and again. That is what Buildroot went
through: see [1] or [3]

For Yocto see [4][5][6]

Both do hand copy ! config/git management is not convenient neither.

> 
> What is the use case of custom DT injection like this ?

For example,

 - Bring-up. The board needs U-Boot to boot before its device tree is
   anywhere near upstream, and the .dts changes several times a day.
   Pointing the build at the directory beats a patch per iteration !

 - Linux sync. A DT that is upstream in Linux but not yet in U-Boot.
   dts/upstream follows a kernel release, so a board whose .dts landed
   in the kernel waits for the next sync.

 - Board variants. A carrier or a memory variant of a supported board,
   like the VisionFive 2 8GiB report [7], needs its own DTB but is not
   something U-Boot wants a defconfig for. The variant .dts lives with
   the product and builds against the SoC .dtsi of the U-Boot release.

How to handle those cases + Buildroot and Yocto without such proposal
for uboot ?

best regards,
  Vincent