Re: [PATCH v2 2/4] dt-bindings: phy: qcom,msm8998-qmp-usb3-phy: Add support for Shikra

[Krzysztof Kozlowski <krzk@kernel.org>]

On 07/05/2026 13:37, Krishna Kurapati wrote:
> 
> 
> On 5/5/2026 7:30 PM, Krzysztof Kozlowski wrote:
>> On 05/05/2026 15:57, Krishna Kurapati wrote:
>>>
>>>
>>> On 5/5/2026 6:59 PM, Krzysztof Kozlowski wrote:
>>>> On 05/05/2026 15:27, Krishna Kurapati wrote:
>>>>>
>>>>>
>>>>> On 5/5/2026 4:22 PM, Krzysztof Kozlowski wrote:
>>>>>> On 05/05/2026 12:49, Krzysztof Kozlowski wrote:
>>>>>>> On Mon, May 04, 2026 at 10:36:57PM +0530, Krishna Kurapati wrote:
>>>>>>>> Declare the USB-C QMP PHY present on the Qualcomm Shikra platform.
>>>>>>>>
>>>>>>>> Signed-off-by: Krishna Kurapati <krishna.kurapati@oss.qualcomm.com>
>>>>>>>> ---
>>>>>>>>     .../devicetree/bindings/phy/qcom,msm8998-qmp-usb3-phy.yaml      | 2 ++
>>>>>>>>     1 file changed, 2 insertions(+)
>>>>>>>
>>>>>>> Reviewed-by: Krzysztof Kozlowski <krzysztof.kozlowski@oss.qualcomm.com>
>>>>>>
>>>>>> ... and then I looked at the driver. So un-reviewed. Devices are clearly
>>>>>> compatible. If not, explain what is not compatible.
>>>>>>
>>>>> Talos uses GCC_USB3_PRIM_PHY_AUX_CLK.
>>>>>
>>>>> In Shikra, we are using GCC_USB3_PRIM_PHY_COM_AUX_CLK. We don't have
>>>>> GCC_USB3_PRIM_PHY_AUX_CLK.
>>>>>
>>>>> Hence, I didn't use a fallback compatible.
>>>>
>>>> This still explains nothing. How different clock makes interface for SW
>>>> incompatible exactly?
>>>>
>>> So I went by the naming. AUX vs COM_AUX.
>>
>> The naming does not matter. If the clock is called
>> "no_one_expects_spanish_inquisition", does that make software
>> incompatible? Why would the name itself matter?
>>
>>>
>>> Can I use a fallback compatible and in DT vote for "COM_AUX" clock with
>>> clock-names mentioning "aux" ?
>>
>> I don't know, I asked what is different in software interface.
>>
> 
> Hi Krzysztof,
> 
>   I checked with the hw team here and found out two things.
> 
>   1. Shikra is a spinoff of Agatti and its sw interface (clocks used and 
> regulators used) is the same as agatti.
> 
>   2. I thought we could use qcm2290 as a fallback since the phy register 
> init sequence is the same for Talos/Shikra/Agatti. The difference 
> between Talos and agatti when checked in the driver was the init load 
> settings. I checked with the hw team and they suggested using the init 
> load settings which talos was using.
> 
>   Hence both these compatibles (qcm2290 and qcs615) cannot be used as 
> fallback for Shikra.

Then I do not understand why you are using qcs615_usb3phy_cfg for
Shikra. You say that the initialization is different, but you use
exactly the same initialization. So in a meaning of compatibility
between hardware for Devicetree they are compatible.

Best regards,
Krzysztof