Re: [PATCH 1/2] dt-bindings: leds: backlight: add Kinetic KTD3137

[Krzysztof Kozlowski <krzk@kernel.org>]

On 11/11/2026 13:41, Daniel Thompson wrote:
> On Wed, Nov 11, 2026 at 01:11:13PM +0100, Krzysztof Kozlowski wrote:
>> On 03/11/2026 18:10, Daniel Thompson wrote:
>>> On Tue, Nov 03, 2026 at 03:21:45PM +0000, Roman Vivchar wrote:
>>>>
>>>> In the driver I've used devm_regulator_get_enable(), rather than _optional(),
>>>> since my understanding is that the non-optional helper is a standard kernel
>>>> API for required supplies (with regulator core warning and fallback to dummy
>>>> regulator in case DT omits it).
>>>
>>> That dummy fallback essentially makes it optional. On a board with an
>>> always-on supply then there is no need to include vin-supply in the
>>> DTB. The driver will work just fine without it.
>>
>> There is a need, because this device needs a supply. How you describe
>> that supply in DTS is a different story - can be always-on, can be
>> missing etc.
> 
> If it is missing (but listed as required) then won't a DT that omits this
> property fail schema validation? If is legitimate for the property to
> be missing then I'd view this to be a spurious fail

It is not legitimate for the property to be missing. I said - it is needed.

> 
> We certainly didn't list basic supplies as required in other recent
> backlight reviews:
> https://lore.kernel.org/all/20260529-topic-sm8650-ayaneo-pocket-s2-sy7758-v5-1-03aacd49747c@linaro.org/
> 
> Is this something DT maintainers want to see tightened up when new
> bindings are introduced?

We always ask for required supplies to be provided. There might be an
exception, maybe such one was pointed during multiple revisions of above
patchset, not sure.

Best regards,
Krzysztof