Re: [PATCH 08/10] dt-bindings: media: qcom: Add Qualcomm MIPI C-/D-PHY schema for CSIPHY IPs

[Krzysztof Kozlowski <krzk@kernel.org>]

On 12/06/2025 13:27, Vladimir Zapolskiy wrote:
> On 6/12/25 14:02, Krzysztof Kozlowski wrote:
>> On 12/06/2025 09:57, Vladimir Zapolskiy wrote:
>>> On 6/12/25 10:39, Krzysztof Kozlowski wrote:
>>>> On 12/06/2025 09:38, Krzysztof Kozlowski wrote:
>>>>> On 12/06/2025 03:15, Vladimir Zapolskiy wrote:
>>>>>> Add dt-binding schema for Qualcomm CAMSS CSIPHY IP, which provides
>>>>>> MIPI C-PHY/D-PHY interfaces on Qualcomm SoCs.
>>>>>>
>>>>>> Signed-off-by: Vladimir Zapolskiy <vladimir.zapolskiy@linaro.org>
>>>>>> ---
>>>>>> RFC verion of the change:
>>>>>> * https://lore.kernel.org/all/20250513143918.2572689-1-vladimir.zapolskiy@linaro.org/
>>>>>>
>>>>>> Changes from RFC to v1:
>>>>>> * moved from phy/qcom,csiphy.yaml to media/qcom,csiphy.yaml,
>>>>>> * added 'clock-names' property,
>>>>>> * removed SM8250 CSIPHY specifics, a generic binding is good enough for now,
>>>>
>>>>
>>>> Now I noticed this... weird change and clearly a no-go.
>>>>
>>>> Device binding cannot be generic, so it is not good enough for now.
>>>> Please write specific bindings for specific hardware.
>>>>
>>>
>>> Can I add platform specific changes on top of the displayed generic one
>>> like in Documentation/devicetree/bindings/display/msm/dsi-phy-10nm.yaml
>>> etc?
>>>
>>> The generic compatible is sufficienlty good for adding the enhanced
>>> CSIPHY support to any currently present in the upstream platform CAMSS.
>>>
>>> Obviously I can rename it to something SoC-specific, but then a question
>>> arises, if a selected platform has to be a totally new one in the upstream,
>>> or it could be among any of platforms with a ready CAMSS, and a backward
>>> compatibility is preserved by these series and the new CSIPHY dt bindings.
>>
>> Just use a specific compatible for the actual hardware this is being
>> added for. I don't understand why this is different than all other work
>> upstream.
> 
> There are very close examples in upstream, for instance that's a generic
> value from Documentation/devicetree/bindings/display/msm/dsi-phy-10nm.yaml:
> 
> properties:
>    compatible:
>      enum:
>        - qcom,dsi-phy-10nm
>        - qcom,dsi-phy-10nm-8998

That's ancient now style. Don't use something from 10 years ago as example.

> 
> To save time reviewing the next version of the same change, will you
> accept a list of acceptable compatible properties like this one?
> 
> properties:
>    compatible:
>      enum:
>        - qcom,csiphy

No. You cannot have generic compatible. We keep repeating this all the
time, so this is nothing new.

>        - qcom,sm8250-csiphy
> 

Best regards,
Krzysztof