linux-kernel - Re: [PATCH v1 2/6] dt-bindings: mediatek,mt6779-keypad: use unevaluatedProperties

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Message-ID: <874jzaj0m5.fsf@baylibre.com>
Date:   Thu, 21 Jul 2022 11:06:42 +0200
From:   Mattijs Korpershoek <mkorpershoek@...libre.com>
To:     Krzysztof Kozlowski <krzysztof.kozlowski@...aro.org>,
        Rob Herring <robh+dt@...nel.org>,
        Krzysztof Kozlowski <krzysztof.kozlowski+dt@...aro.org>,
        Dmitry Torokhov <dmitry.torokhov@...il.com>,
        Matthias Brugger <matthias.bgg@...il.com>
Cc:     linux-kernel@...r.kernel.org, linux-input@...r.kernel.org,
        Fabien Parent <parent.f@...il.com>, devicetree@...r.kernel.org,
        linux-mediatek@...ts.infradead.org,
        Fabien Parent <fparent@...libre.com>,
        linux-arm-kernel@...ts.infradead.org
Subject: Re: [PATCH v1 2/6] dt-bindings: mediatek,mt6779-keypad: use
 unevaluatedProperties

On Wed, Jul 20, 2022 at 19:14, Krzysztof Kozlowski <krzysztof.kozlowski@...aro.org> wrote:

> On 20/07/2022 16:48, Mattijs Korpershoek wrote:
>> writing-bindings.rst states:
>>> - If schema includes other schema (e.g. /schemas/i2c/i2c-controller.yaml) use
>>>   "unevaluatedProperties:false". In other cases, usually use
>>>   "additionalProperties:false".
>> 
>> mt6779-keypad includes matrix-keymap.yaml so replace additionalProperties:false
>> by unevaluatedProperties:false.
>
> This is not sufficient explanation. You now allow all properties from
> matrix-keymap.yaml, which might be desired or might be not (e.g. they
> are not valid for this device). Please investigate it and mention the
> outcome.

Hi Krzysztof,

Thank you for your prompt review.

In mt6779_keypad_pdrv_probe(), we call
* matrix_keypad_parse_properties() which requires keypad,num-rows and keypad,num-cols.
* matrix_keypad_build_keymap() which uses linux,keymap

Therefore, all properties from matrix-keymap.yaml are
required by the mt6779-keypad driver.

In v2, I will add the above justification and also add all 3 properties
in the "required" list.

Initially, I did not do this because from a dts/code perspective it seemed
interesting to split out SoC specific keyboard node vs board specific key configuration:
* [PATCH v1 5/6] arm64: dts: mediatek: mt8183: add keyboard node # SoC specific
* [PATCH v1 6/6] arm64: dts: mediatek: mt8183-pumpkin: add keypad support # board specific

What would be the recommend approach for above?
I see at least 2:
* "move the whole keyboard node into the board file (mt8183-pumpkin.dts)" even if it generates
  duplication between boards using the same SoC.
* "add a "dummy keymap,row,cols" properties in the soc node which can be overriden in board file.
  For example, use rows and cols = 0 which would have the driver early exit.

Thanks,
Mattijs

>
> Best regards,
> Krzysztof