Re: [PATCH 3/5] arm64: dts: imx8mp: Enable HS400-ES

[Krzysztof Kozlowski <krzk@kernel.org>]

On 28/03/2022 15:42, Ahmad Fatoum wrote:
> On 28.03.22 15:14, Krzysztof Kozlowski wrote:
>> On 28/03/2022 15:07, Ahmad Fatoum wrote:
>>> On 28.03.22 14:56, Krzysztof Kozlowski wrote:
>>>> You could also add two cases:
>>>> 1. three compatibles, deprecated: True,
>>>> 2. two compatibles, without imx7d.
>>>>
>>>> Existing DTS stays with three compatibles for two years and later gets
>>>> converted to two compatibles. New DTS should use two compatibles.
>>>>
>>>> It's quite a lot of churn, but would make in the long term bindings
>>>> correct and also not break other users/projects.
>>>
>>> I don't see why we need to deprecate the old binding. New SoCs
>>> can be imx8mm-usdhc compatible from the beginning and need not
>>> care about the old binding. Existing SoCs can just remain imx7d-usdhc
>>> compatible as they are now.
>>>
>>> I don't see what the deprecation accomplishes.
>>
>> It avoids to have too many entries of imx8mm (imx8mm alone,
>> imx8mm+imx7d, imx8xx+imx8mm+imx7d).
> 
> I see. I assume use of deprecated binding will be reported on a dtbs_check?

Unfortunately no, at least not yet. :-(

> If so, the expectation is that downstream projects run dtbs_check on their
> imported Linux DT repository, see the deprecation warning and extend
> their drivers to comply with it.
> 
> Some time later upstream will remove the deprecated binding and adjust
> the device trees. This works for me.
>

Yes. Plus this gives the notice to downstream projects, to comply with
the change of DTS.

Best regards,
Krzysztof