Re: [PATCH v8 2/2] phy: qcom-mipi-csi2: Add a CSI2 MIPI DPHY driver

From: Bryan O'Donoghue <bod@kernel.org>
To: Vladimir Zapolskiy <vladimir.zapolskiy@linaro.org>,
	Bryan O'Donoghue <bryan.odonoghue@linaro.org>,
	Dmitry Baryshkov <dmitry.baryshkov@oss.qualcomm.com>
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>,
	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 v8 2/2] phy: qcom-mipi-csi2: Add a CSI2 MIPI DPHY driver
Date: Wed, 3 Jun 2026 22:12:56 +0100	[thread overview]
Message-ID: <41ab1685-3d0a-4c8b-b7a9-6e9299c48400@kernel.org> (raw)
In-Reply-To: <6e962010-8097-4b52-9369-0727c0d5a31a@linaro.org>

On 03/06/2026 21:42, Vladimir Zapolskiy wrote:
>>> Split configurations explicitly use other lanes for clocks. E.g. check
>>> the RB5 Navigation schematics, CAM0B connector.
>> Can you please check:
>>
>> CSI_3PHASE_COMMON.CSI_COMMON_CTRL5
>>
>> 0 LN0_PWRDN_B Lane 0
>> ...
>> 7 LNCK_PWRDN_B Clock Lane
> Please note that media devices have a numeration scheme of lanes starting
> from 1 (it'd be easy to check/confirm it), for instance today CAMSS has
> lane numeration starting from 0 is out of the accepted scheme, and here
> it'd be better to correct it and not enter the same pit.

Yes fair point CAMSS has done this wrong since forever. data-lanes = <1 
2 3 4> => LN0, LN1, LN2, LN3>
> I don't have access to the IP spec, anyway I do not grasp it, where are
> 8 lanes on the CSIPHY found? Each CSIPHY IP has 4+1 D-PHY lanes, not 8.

Max CSI2 data-lanes is 8

#define V4L2_MBUS_CSI2_MAX_DATA_LANES          8

That doesn't really explain why this register has seven data-lanes and 
one-clock lane.

It just is what it is.

---
bod

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