Re: [PATCH v2 1/2] dt-bindings: phy: qcom: Add CSI2 C-PHY/DPHY schema

From: Bryan O'Donoghue <bod@kernel.org>
To: Krzysztof Kozlowski <krzk@kernel.org>,
	Bryan O'Donoghue <bryan.odonoghue@linaro.org>
Cc: 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>,
	Vladimir Zapolskiy <vladimir.zapolskiy@linaro.org>,
	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
Subject: Re: [PATCH v2 1/2] dt-bindings: phy: qcom: Add CSI2 C-PHY/DPHY schema
Date: Thu, 26 Feb 2026 09:24:34 +0000	[thread overview]
Message-ID: <2665866f-e967-40df-a25c-1492cb707291@kernel.org> (raw)
In-Reply-To: <20260226-carmine-cockle-of-prosperity-b6baf2@quoll>

On 26/02/2026 07:37, Krzysztof Kozlowski wrote:
> On Wed, Feb 25, 2026 at 02:59:12PM +0000, Bryan O'Donoghue wrote:
>> Add a base schema initially compatible with x1e80100 to describe MIPI CSI2
>> PHY devices.
>>
>> The hardware can support both C-PHY and D-PHY modes. The CSIPHY devices
>> have their own pinouts on the SoC as well as their own individual voltage
>> rails.
>>
>> The need to model voltage rails on a per-PHY basis leads us to define
>> CSIPHY devices as individual nodes.
>>
>> Two nice outcomes in terms of schema and DT arise from this change.
>>
>> 1. The ability to define on a per-PHY basis voltage rails.
>> 2. The ability to require those voltage.
>>
>> We have had a complete bodge upstream for this where a single set of
>> voltage rail for all CSIPHYs has been buried inside of CAMSS.
>>
>> Much like the I2C bus which is dedicated to Camera sensors - the CCI bus in
>> CAMSS parlance, the CSIPHY devices should be individually modelled.
>>
>> Signed-off-by: Bryan O'Donoghue <bryan.odonoghue@linaro.org>
> 
> The entire point of separate CSI PHY was to change new devices. That's
> why I was postponing TWO new bindings. There is little point in change
> existing bindings, it's just a lot of work with little benefit.

Since the x1e dtsi isn't upstream yet though.

> And the beauty is that you did not even had to do the work yourself,
> because the contributors of new device would need to come with CSI PHY
> split.
I mean I'm happy to do that work myself, idle hands make the Devil's work.

?

---
bod

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