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

[Konrad Dybcio]

On 5/17/26 9:16 PM, Dmitry Baryshkov wrote:
> On Fri, May 15, 2026 at 09:06:21PM +0530, Krishna Kurapati wrote:
>>
>>
>> On 5/14/2026 8:07 PM, Krzysztof Kozlowski wrote:
>>> On 14/05/2026 08:22, Krishna Kurapati wrote:
>>>>
>>>>
>>>> On 5/14/2026 12:26 AM, Krzysztof Kozlowski wrote:
>>>>> 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 at oss.qualcomm.com>
>>>>>>>>>>>>> ---
>>>>>>>>>>>>>       .../devicetree/bindings/phy/qcom,msm8998-qmp-usb3-phy.yaml      | 2 ++
>>>>>>>>>>>>>       1 file changed, 2 insertions(+)
>>>>>>>>>>>>
>>>>>>>>>>>> Reviewed-by: Krzysztof Kozlowski <krzysztof.kozlowski at 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.
>>>>>
>>>> Hi Krzysztof,
>>>>
>>>>    There are 3 things:
>>>>
>>>> 1. Clocks used:
>>>> -> Talos supports AUX Clock since it supports DP over USB.
>>>> -> Agatti and Shikra use COM_AUX clock since they dont support DP over USB.
>>>>
>>>> 2. Phy register Init sequence - same for all 3 targets
>>>>
>>>> 3. Regulator init load:
>>>> -> Different for both Talos and Agatti
>>>> -> Recommendation is to use Talos regulator load values.
>>>>
>>>> SW interface wise, shikra is comaptible with agatti. If we use agatti as
>>>> fallback, we would end up using the platform data of Agatti where the
>>>> regulator init load is not suitable for Shikra. Hence not using Agatti
>>>> as fallback.
>>>>
>>>> Coming to driver changes, I used qcs615_cfg because it has required phy
>>>> register sequence and regulator init load as needed by shikra.
>>>
>>> So is it compatible with QCS615? If not, then something is incomplete or
>>> confusing. The driver uses the same software interface.
>>>
>> Sorry for the confusion. The Talos compatible represents the USB/DP PHY with
>> aux clock input, while Shikra is a USB-only PHY with com_aux input clock, so
>> the two PHYs are not compatible with each other.
> 
> According to the memory map, there is an (unused) DP registers part
> right after the QMP USB3 PHY. So, sofware-wise it is compatible to
> Talos. Having the different clock input means different integration of
> the block rather than the differences in the hardware block.
> 
> So, the block should be compatible to qcom,qcs615-qmp-usb3-dp-phy

It should still carry its own compatible though, to let the driver
disallow powering up the DP part

Konrad