Re: [PATCH v2 1/2] dt-bindings: pinctrl: mediatek: add support for mt8196

[Krzysztof Kozlowski <krzk@kernel.org>]

On 13/01/2025 14:20, AngeloGioacchino Del Regno wrote:
>>> +
>>> +        properties:
>>> +          pinmux:
>>> +            description:
>>> +              Integer array, represents gpio pin number and mux setting.
>>> +              Supported pin number and mux varies for different SoCs, and are
>>> +              defined as macros in dt-bindings/pinctrl/mt8196-pinfunc.h
>>> +              directly, for this SoC.
>>> +
>>> +          drive-strength:
>>> +            enum: [2, 4, 6, 8, 10, 12, 14, 16]
>>> +
>>> +          drive-strength-microamp:
>>> +            enum: [125, 250, 500, 1000]
>>
>> Why duplicating properties? No, use only one.
>>
> 
> The problem here is not entirely about duplicating properties, and I'm not
> sure that the reason is actually acceptable (but being this a special case
> the `description` field would be mandatory to have IMO!!).
> 
> So, the reason for this separation is that the drive-strength-microamp does
> activate a special feature in the controller called "advanced drive strength
> mode", which is switching to different shunts that will decrease the power
> efficiency of the chip (by an ignorable amount, if that's one pin - but if
> that goes to something like 100 pins, it's not ignorable anymore).
> 
> I'd be happy if we could let them retain both properties after putting a
> clear description of what's happening and why there are two of them.
It would be fine then, but please add some sort of description to these
fields documenting that difference.

Best regards,
Krzysztof