[PATCH 00/21] Qualcomm generic board support

Krzysztof Kozlowski krzysztof.kozlowski at linaro.org
Tue Dec 5 11:09:28 CET 2023

On 05/12/2023 10:45, Sumit Garg wrote:
> + U-boot custodians list
> On Tue, 5 Dec 2023 at 12:58, Krzysztof Kozlowski
> <krzysztof.kozlowski at linaro.org> wrote:
>> On 05/12/2023 08:13, Sumit Garg wrote:
>>>>> @DT bindings maintainers,
>>>>> Given the ease of maintenance of DT bindings within Linux kernel
>>>>> source tree, I don't have a specific objection there. But can we ease
>>>>> DTS testing for firmware/bootloader projects by providing a versioned
>>>>> release package for DT bindings? Or if someone else has a better idea
>>>>> here please feel free to chime in.
>>>> This doesn't work for you?:
>>>> https://git.kernel.org/pub/scm/linux/kernel/git/devicetree/devicetree-rebasing.git/
>>> Thanks, this is certainly a good step which I wasn't aware of. Further
>>> simplification can be done to decouple devicetree source files from DT
>>> bindings.
>> Why?
> I suppose you are already aware that Linux DTS files are a subset of
> what could be supported by devicetree schemas. There can be
> firmware/bootloader specific properties (one example being [1]) which
> Linux kernel can simply ignore. Will you be willing to add all of
> those DT properties to Linux DTS files and maintain them?

We already added them and we already maintain them. DTS describes the
hardware, not the OS-subset of the hardware.

> However, DT bindings are something which should be common, the
> hardware description of a device should be universal. IMO, splitting

Both DT bindings and DTS should be common. I don't see the difference.

> DT bindings alone would ease the compliance process for u-boot drivers
> in quite similar manner to Linux drivers.
> [1] https://github.com/devicetree-org/dt-schema/blob/main/dtschema/schemas/bootph.yaml
>>> AFAIK, DT bindings should be forwards and backwards
>>> compatible.
>> The same with DTS.
>>> So if you pick up DTS or DTB from any project tree
>>> (upstream kernel or stable kernel or u-boot) then DT schema validation
>>> would ensure that corresponding DTS or DTB doesn't regress the DT
>>> bindings.
>> And why is this argument to decouple DTS from bindings?
> See above.

It's not really explained there. You can pick up DTS from any project
and validate it against the repo Rob mentioned or against kernel.
Whether DTS is in that repo or not, does not matter for your validation.

>>> Ideally, it should be more user/CI friendly if DT bindings can be
>>> easily installed alongside devicetree schema tools [1].
>>> [1] https://github.com/devicetree-org/dt-schema
>> Does it mean you will work on this?
> I am happy to collaboratively work with DT bindings maintainers and
> the u-boot community once we can reach a consensus on the above.
> Basically the main motive here is to validate DTS files present in the
> u-boot tree and be able to reliably pass them to whichever Linux
> kernel version you are trying to boot. IOW, make Linux distros to
> reliably boot with devicetree supplied by u-boot.

So the answer is "no" on the proposal you mentioned before. Sure, maybe
someone will pick it up.

Best regards,

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