Re: [PATCH v5 1/2] dt-bindings: phy: qcom: Add CSI2 C-PHY/DPHY schema

[Bryan O'Donoghue <bod@kernel.org>]

On 27/03/2026 23:23, Dmitry Baryshkov wrote:
> On Sat, Mar 28, 2026 at 01:12:22AM +0200, Vladimir Zapolskiy wrote:
>> On 3/28/26 00:29, Bryan O'Donoghue wrote:
>>> On 27/03/2026 20:51, Dmitry Baryshkov wrote:
>>>>> That's just not true. If you read the camx source code you can see
>>>>> split/combo mode 2+1 1+1 data/clock mode requires special programming of the
>>>>> PHY to support.
>>>> This needs to be identified from the data-lanes / clock-lanes topology.
>>>> And once you do that, there would be (probably) no difference in the
>>>> hardware definition.
>>>>
>>>>
>>>> In other words, I'd also ask to drop this mode from the DT. This
>>>> infromation can and should be deduced from other, already-defined
>>>> properties.
>>>
>>> It still needs to be communicated to the PHY from the controller,
>>> however that is not a problem I am trying to solve now.
>>>
>>> If I can't get consensus for PHY_QCOM_CSI2_MODE_SPLIT_DPHY then so be it.
>>>
>>> I'll aim for DPHY only and we can come back to this topic when someone
>>> actually tries to enable it.
>>>
>>
>> DPHY may be the only supported phy type in the driver, it does not matter
>> at this point, however it's totally essential to cover the called by you
>> 'split mode' right from the beginning in the renewed device tree binding
>> descriptions of CAMSS IPs to progress further.
> 
> Okay. How would we describe that there are two sensors connected to the
> single PHY anyway? How would it be described with the current bindings?
> 
> --
> With best wishes
> Dmitry

Assuming you add endpoints to the PHY i.e. that is what Neil appears to 
be asking for and I personally am _fine_ with that, then it should just be

port@0
port@1

if port@1 exists, you know you are in split-phy mode.

Its actually straight forward enough, really. To be clear though I can 
write that yaml - the _most_ support I'm willing to put into the PHY 
code is to detect the port@1 and say "nope not supported yet", since 
like CPHY its not.

---
bod