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Date:   Fri, 29 Apr 2022 18:35:58 +0200
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Subject: Re: [PATCH 1/2] dt-bindings: google,cros-ec-keyb: Introduce switches
 only compatible
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To:     Doug Anderson <dianders@chromium.org>,
        Stephen Boyd <swboyd@chromium.org>
Cc:     Dmitry Torokhov <dmitry.torokhov@gmail.com>,
        LKML <linux-kernel@vger.kernel.org>, patches@lists.linux.dev,
        Rob Herring <robh+dt@kernel.org>,
        "open list:OPEN FIRMWARE AND FLATTENED DEVICE TREE BINDINGS" 
        <devicetree@vger.kernel.org>, Benson Leung <bleung@chromium.org>,
        Guenter Roeck <groeck@chromium.org>,
        Hsin-Yi Wang <hsinyi@chromium.org>,
        "Joseph S. Barrera III" <joebar@chromium.org>
References: <20220427203026.828183-1-swboyd@chromium.org>
 <20220427203026.828183-2-swboyd@chromium.org>
 <CAD=FV=Vtnj+8FYdBSvsud9fGEbo7N1HSjXA3rH3f8FMJsuVR1A@mail.gmail.com>
From:   Krzysztof Kozlowski <krzk@kernel.org>
In-Reply-To: <CAD=FV=Vtnj+8FYdBSvsud9fGEbo7N1HSjXA3rH3f8FMJsuVR1A@mail.gmail.com>
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On 29/04/2022 18:31, Doug Anderson wrote:
>>    - $ref: "/schemas/input/matrix-keymap.yaml#"
>>
>>  properties:
>>    compatible:
>> -    const: google,cros-ec-keyb
>> +    oneOf:
>> +      - items:
>> +          - const: google,cros-ec-keyb-switches
>> +          - const: google,cros-ec-keyb
>> +      - items:
>> +          - const: google,cros-ec-keyb
> 
> nit: if I come back and read this binding later I'm not sure it would
> be obvious which compatible I should pick. Can we give any description
> here that indicates that the first choice is for devices that _only_
> have buttons and switches (the google,cros-ec-keyb is just for
> backward compatibility) and the second choice is for devices that have
> a physical keyboard and _also_ possibly some buttons/switches?
> 
> I could also imagine people in the future being confused about whether
> it's allowed to specify matrix properties even for devices that don't
> have a matrix keyboard. It might be worth noting that it's allowed (to
> support old drivers that might still be matching against the
> google,cros-ec-keyb compatible) but not required.

+1

> 
> 
>>    google,needs-ghost-filter:
>>      description:
>> @@ -50,7 +56,7 @@ examples:
>>    - |
>>      #include <dt-bindings/input/input.h>
>>      cros-ec-keyb {
>> -        compatible = "google,cros-ec-keyb";
>> +        compatible = "google,cros-ec-keyb-switches", "google,cros-ec-keyb";
> 
> Feels like we should create a second example?

+1 as well, because it really would confuse what's the difference
between them.

Best regards,
Krzysztof