Re: [PATCH v13 1/2] dt-bindings: phy: qcom: Add CSI2 C-PHY/DPHY schema

From: Vladimir Zapolskiy <vladimir.zapolskiy@linaro.org>
To: Bryan O'Donoghue <bod@kernel.org>,
	Bryan O'Donoghue <bryan.odonoghue@linaro.org>,
	Vinod Koul <vkoul@kernel.org>,
	Kishon Vijay Abraham I <kishon@kernel.org>,
	Rob Herring <robh@kernel.org>,
	Krzysztof Kozlowski <krzk+dt@kernel.org>,
	Conor Dooley <conor+dt@kernel.org>,
	Neil Armstrong <neil.armstrong@linaro.org>
Cc: linux-arm-msm@vger.kernel.org, linux-phy@lists.infradead.org,
	linux-media@vger.kernel.org, devicetree@vger.kernel.org,
	linux-kernel@vger.kernel.org,
	Krzysztof Kozlowski <krzysztof.kozlowski@oss.qualcomm.com>
Subject: Re: [PATCH v13 1/2] dt-bindings: phy: qcom: Add CSI2 C-PHY/DPHY schema
Date: Tue, 21 Jul 2026 12:56:53 +0300	[thread overview]
Message-ID: <345ca98e-09f6-4965-87bb-e64dac096498@linaro.org> (raw)
In-Reply-To: <88ae6662-cb85-4e3a-bbb5-1b536348df34@kernel.org>

On 7/21/26 12:39, Bryan O'Donoghue wrote:
> On 21/07/2026 09:17, Vladimir Zapolskiy wrote:
>>> +  "#phy-cells":
>>> +    const: 1
>>> +    description:
>>> +      The single cell specifies the PHY operating mode.
>> This has been reported before, #phy-cells shall be 0, the operation
>> mode is selected by bus-type of endpoints as it is described in
>> video-interfaces.yaml
>>
>> Two competing values are redundant and it opens a door to a wrong
>> hardware description, the technical discussion has not been started yet.
> 
> So as I said before, I'm following Rob Herring's input on this and
> Krzysztof has given RB for this binding. At this stage, I don't see
> scope to change it.
> 
> Adding endpoints was already a compromise to address your feedback,
> which I hoped would bring you on board with the design.

That's my comment dated March 27, 2026, and it says moving phy type
from phy cell to the endpoint property excludes the need to set any
phy cells:

https://lore.kernel.org/linux-arm-msm/e37ce438-12c7-462d-b2bc-1351be62b806@linaro.org/

The technical comment is left unresponded so far since then.

Since there is no expected phy cells to get on consumer's side, and
since there is another link between CSIPHY and CSID described in
video-interfaces.yaml, any kind of dependency of this IP on phy can
be just removed, which serves the purpose of hardware description
simplification.

> 
> There are several SoC bindings as well as new CPHY features which are
> gated on these changes.
> 
> Vinod, Kishon I'd request to merge the changes as-is.
> 

-- 
Best wishes,
Vladimir

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