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

[Dmitry Baryshkov]

On Wed, Jun 10, 2026 at 03:36:20PM +0200, Konrad Dybcio wrote:
> 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

Why? The DP part is there, in the PHY, pretty much like it's present on
most of USBC platforms. I assume it can be powered on.  There is no
point in it though as there is no DP controller (nor DP pins).

-- 
With best wishes
Dmitry