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Message-ID: <9caaa63d-cf5a-46f8-93db-9fbc00850d8f@linaro.org>
Date: Mon, 13 May 2024 11:38:03 +0200
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Subject: Re: [PATCH 2/2] dt-bindings: panel-simple-dsi: Add generic panel-dsi
To: Johan Adolfsson <Johan.Adolfsson@axis.com>,
 Neil Armstrong <neil.armstrong@linaro.org>,
 Jessica Zhang <quic_jesszhan@quicinc.com>, Sam Ravnborg <sam@ravnborg.org>,
 Maarten Lankhorst <maarten.lankhorst@linux.intel.com>,
 Maxime Ripard <mripard@kernel.org>, Thomas Zimmermann <tzimmermann@suse.de>,
 David Airlie <airlied@gmail.com>, Daniel Vetter <daniel@ffwll.ch>,
 Rob Herring <robh+dt@kernel.org>,
 Krzysztof Kozlowski <krzysztof.kozlowski+dt@linaro.org>,
 Conor Dooley <conor+dt@kernel.org>, Thierry Reding <thierry.reding@gmail.com>
Cc: "dri-devel@lists.freedesktop.org" <dri-devel@lists.freedesktop.org>,
 "linux-kernel@vger.kernel.org" <linux-kernel@vger.kernel.org>,
 "devicetree@vger.kernel.org" <devicetree@vger.kernel.org>,
 kernel <kernel@axis.com>
References: <20240418-foo-fix-v1-0-461bcc8f5976@axis.com>
 <20240418-foo-fix-v1-2-461bcc8f5976@axis.com>
 <c739a512-9a75-4f48-b5ef-801191c298f5@linaro.org>
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 <PAWPR02MB9281B32E144205CCEEF0C53D9BE22@PAWPR02MB9281.eurprd02.prod.outlook.com>
From: Krzysztof Kozlowski <krzysztof.kozlowski@linaro.org>
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On 13/05/2024 11:34, Johan Adolfsson wrote:
> 
> 
>> -----Original Message-----
>> From: Krzysztof Kozlowski <krzysztof.kozlowski@linaro.org> 
>> Sent: den 22 april 2024 22:57
>> To: Johan Adolfsson <Johan.Adolfsson@axis.com>; Neil Armstrong <neil.armstrong@linaro.org>; Jessica Zhang <quic_jesszhan@quicinc.com>; Sam Ravnborg <sam@ravnborg.org>; Maarten Lankhorst <maarten.lankhorst@linux.intel.com>; Maxime Ripard <mripard@kernel.org>; Thomas Zimmermann <tzimmermann@suse.de>; David Airlie <airlied@gmail.com>; Daniel Vetter <daniel@ffwll.ch>; Rob Herring <robh+dt@kernel.org>; Krzysztof Kozlowski <krzysztof.kozlowski+dt@linaro.org>; Conor Dooley <conor+dt@kernel.org>; Thierry Reding <thierry.reding@gmail.com>
>> Cc: dri-devel@lists.freedesktop.org; linux-kernel@vger.kernel.org; devicetree@vger.kernel.org; kernel <kernel@axis.com>
>> Subject: Re: [PATCH 2/2] dt-bindings: panel-simple-dsi: Add generic panel-dsi>
>>
>> On 22/04/2024 16:34, Johan Adolfsson wrote:
>>>
>>>
>>> -----Original Message-----
>>> From: Krzysztof Kozlowski <krzysztof.kozlowski@linaro.org>
>>> Sent: den 19 april 2024 01:05
>>> To: Johan Adolfsson <Johan.Adolfsson@axis.com>; Neil Armstrong 
> ..
>>> Subject: Re: [PATCH 2/2] dt-bindings: panel-simple-dsi: Add generic 
>>> panel-dsi
>>>
>>>> On 18/04/2024 16:01, Johan Adolfsson wrote:
>>>>> panel-dsi is similar to panel-dpi with overridable timings
>>>>
>>>> ???
>>>
>>> I guess a more correct description would be "panel-dsi is a fallback 
>>> in a similar way that panel-dpi is in panel-dpi.yaml .."?
>>
>> I meant how does it explain the hardware.
> 
> In our case it's actually an FPGA that takes MIPI DSI input and can support multiple different kind of displays, and what I want to achieve
> is to avoid specifying a lot of different panel timings in the driver and have that in devicetree instead. 
> I appreciate any suggestions on how to phrase that in an acceptable manner.
> 
>>> ...
>>>>> a/Documentation/devicetree/bindings/display/panel/panel-simple-dsi.y
>>>>> am
>>>>> l
>>>>> +++ b/Documentation/devicetree/bindings/display/panel/panel-simple-d
>>>>> +++ si
>>>>> +++ .yaml
>>>>> @@ -56,6 +56,8 @@ properties:
>>>>>        - samsung,sofef00
>>>>>          # Shangai Top Display Optoelectronics 7" TL070WSH30 1024x600 TFT LCD panel
>>>>>        - tdo,tl070wsh30
>>>>> +        # Generic dsi panel with timing overridable
>>>>> +      - panel-dsi
>>>>
>>>> ? Devices are not generic. This is very confusing and commit msg does not help me. Compatibles *must* be specific, see writing-bindings.
>>>
>>> I guess I see this a generic fallback, that handles any dsi panel as 
>>> long as the correct timing etc is specified in devictree, similar to what panel-dpi is in panel-dpi.yaml Maybe phrasing it similar to panel-dpi.yaml is better?
>>
>> But panel-dpi is quite different. You always have two compatibles. I don't see two compatibles here.
> 
> It doesn't really need two compatibles (in practice at least), the new generic panel-dsi could be enough - I do believe that devices can be generic,
> but I admit that I'm not really "fluent" in devicetree and binding descriptions.

I guess the first comment brought here a bit of naming issue... The
bindings are not "generic".

Best regards,
Krzysztof