Re: [PATCH 1/2] dt-bindings: media: qcom,glymur-camss: Use CSIPHY indices for ports

[Krzysztof Kozlowski <krzk@kernel.org>]

On 05/11/2026 10:18, Nihal Kumar Gupta wrote:
> 
> 
> On 05-11-2026 13:03, Krzysztof Kozlowski wrote:
>>>> What is the problem exactly you are solving?
>>>>
>>> The problem is that CSIPHY4 is connected to CAMSS interface 4, so the
>>> graph should describe it as port@4, not port@2.
>> Nothing like this is explained in commit msg.
>>
> I will update commit message to explain it better.
> 
>>> The previous port@3 description only worked through the X1E80100 resource
>>> table indirection:
>>>
>>>   port@3 -> csiphy_res[3] -> .csiphy.id = 4 -> CSID selects CSIPHY4
>>>
>>> New standalone PHY path:
>>>   port@4 -> no csiphy_res[] lookup -> port number is id 4 -> CSID selects CSIPHY4
>> Then this breaks existing users, no? Anyway, what stops you from having
>> there proper mapping?
>>
> No existing upstream user should break here; this is still part of the Glymur
> CAMSS enablement.
> 
> This follows the earlier discussion that CSIPHY4 should use the
> CAMSS-side interface index as its graph port number:
> 
> https://lore.kernel.org/all/CAFEp6-23L+4+yzVxX815ZA2x1_tN8SpzL7ciNcb9b+gBT67AdQ@mail.gmail.com/

Should use? Since when? Do you have DT maintainers ack on that?

> 
>> Did you find any existing practice of numbering ports logical numbering
>> in this device, but some other logic coming from datasheet? Where?
>>
> 
> Glymur has only CSIPHY0, CSIPHY1 and CSIPHY4; CSIPHY2 and CSIPHY3 are not
> present on the SoC. 

Then CSIPHY4 is basically the third (so @2 counting from 0) input port,
no? Not fifth.

> 
> Using port@2 for CSIPHY4 would require a Glymur-specific port-to-CSIPHY mapping.
> port@4 describes the CAMSS input directly and avoids introducing separate logical
> numbering for Glymur.

Seems you opened a new can of worms, so this needs proper justification.
Again, do you see any recent preexisting DT review which would help to
convince me? I know I usually ask not to use poor existing code as
reason to do the same, but here I actually want to see proofs of current
accepted practice.


Best regards,
Krzysztof