[PATCH v8 2/2] phy: qcom-mipi-csi2: Add a CSI2 MIPI DPHY driver
Vladimir Zapolskiy
vladimir.zapolskiy at linaro.org
Wed Jun 3 16:58:50 PDT 2026
On 6/4/26 00:12, Bryan O'Donoghue wrote:
> 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
>
Judging by the name that's something V4L2 or in other words software
specific, while I do reference to the actual pads of Qualcomm SoCs,
and I do not see 8 differential pairs per a CSIPHY, but only 5 lanes.
If that's correct, the data/clock lane numbers should lay in 1 to 5 range.
> That doesn't really explain why this register has seven data-lanes and
> one-clock lane.
>
> It just is what it is.
>
--
Best wishes,
Vladimir
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