Re: [PATCH] arm64: dts: qcom: sc7280: Update SNPS Phy params for SC7280

[Dmitry Baryshkov]

On Thu, 29 Sept 2022 at 11:54, Krishna Kurapati PSSNV
<quic_kriskura@xxxxxxxxxxx> wrote:
>
>
> On 9/29/2022 1:29 PM, Dmitry Baryshkov wrote:
> > On Thu, 29 Sept 2022 at 10:14, Krishna Kurapati
> > <quic_kriskura@xxxxxxxxxxx> wrote:
> >>
> >> Override the SNPS Phy tuning parameters for SC7280 devices. These
> >> values are common for both trogdor and herobrine variants.
> >
> > They are common for trogdor and herobrine, but should these parameters
> > be a default? In other words, a random new device based on sc7280
> > would more likely use these overrides or the hardware defaults?
> >
> Hi Dmitry,
>
>    Currently there are only two platforms, so I made these changes on
> common dtsi. If a new platform comes (mostly it won't) we can override
> them in platform specific file is what I thought.

This is not how it usually works. The 'sc7280.dtsi' is not a 'common
dtsi' for trogdor and herobrine. It describes the SoC.
Thus in my opinion if these overrides should be a default to all
sc7280 platforms, this patch is fine. If these overrides are
applicable only to the two mentioned platforms, they should go to
respective platform-specific DT files.

>
> Regards,
> Krishna,
> >>
> >> Signed-off-by: Krishna Kurapati <quic_kriskura@xxxxxxxxxxx>
> >> ---
> >>   arch/arm64/boot/dts/qcom/sc7280.dtsi | 7 +++++++
> >>   1 file changed, 7 insertions(+)
> >>
> >> diff --git a/arch/arm64/boot/dts/qcom/sc7280.dtsi b/arch/arm64/boot/dts/qcom/sc7280.dtsi
> >> index 2125803..ae2c23e 100644
> >> --- a/arch/arm64/boot/dts/qcom/sc7280.dtsi
> >> +++ b/arch/arm64/boot/dts/qcom/sc7280.dtsi
> >> @@ -3310,6 +3310,13 @@
> >>                          clock-names = "ref";
> >>
> >>                          resets = <&gcc GCC_QUSB2PHY_SEC_BCR>;
> >> +
> >> +                       qcom,hs-rise-fall-time-bp = <0>;
> >> +                       qcom,squelch-detector-bp = <(-2090)>;
> >> +                       qcom,hs-disconnect-bp = <1743>;
> >> +                       qcom,hs-amplitude-bp = <1780>;
> >> +                       qcom,hs-crossover-voltage-microvolt = <(-31000)>;
> >> +                       qcom,hs-output-impedance-micro-ohms = <2600000>;
> >>                  };
> >>
> >>                  usb_1_qmpphy: phy-wrapper@88e9000 {
> >> --
> >> 2.7.4
> >>
> >
> >



-- 
With best wishes
Dmitry