Re: [PATCH v2 2/2] gpio: aggregator: add gpio-aggregator DT compatible

[Krzysztof Kozlowski <krzk@kernel.org>]

On 11/02/2026 11:36, Bartosz Golaszewski wrote:
> On Wed, Feb 11, 2026 at 11:13 AM Krzysztof Kozlowski <krzk@kernel.org> wrote:
>>
>>>>
>>>>  static const struct of_device_id gpio_aggregator_dt_ids[] = {
>>>> +       {
>>>> +               .compatible = "gpio-aggregator",
>>>> +       },
>>>>         {
>>>>                 .compatible = "gpio-delay",
>>>>                 .data = (void *)FWD_FEATURE_DELAY,
>>>> --
>>>> 2.43.0
>>>>
>>>
>>> Regardless of the DT bindings - this change is perfectly fine. We do
>>
>> You cannot have compatible without DT bindings, so this alone is not
>> "perfectly fine". Maybe you wanted platform_device_id entry for
>> ACPI/legacy/MFD devices?
>>
> 
> Sure you can, you just can't put it into upstream devicetree sources.

No, you cannot. You cannot have undocumented ABI. That's the rule and
upstream DTS does not matter. ABI is also for non-upstream users.

> We have had a compatible for gpio-sim for testing purposes for years.

And I fixed in it 2024...

> Why would it be illegal to enable matching of platform drivers over DT
> for testing purposes?

You can match. You cannot have undocumented ABI. This is the rule.

Best regards,
Krzysztof