Re: [PATCH net-next v11 1/7] dt-bindings: phy: document the serdes PHY on sa8255p

From: Bartosz Golaszewski <brgl@kernel.org>
To: Geert Uytterhoeven <geert@linux-m68k.org>
Cc: Bjorn Andersson <andersson@kernel.org>,
	Konrad Dybcio <konradybcio@kernel.org>,
	 Rob Herring <robh@kernel.org>,
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	 Bartosz Golaszewski <bartosz.golaszewski@linaro.org>,
	 Bartosz Golaszewski <bartosz.golaszewski@oss.qualcomm.com>
Subject: Re: [PATCH net-next v11 1/7] dt-bindings: phy: document the serdes PHY on sa8255p
Date: Mon, 29 Jun 2026 18:54:04 +0200	[thread overview]
Message-ID: <CAMRc=Meb58KCuLXkNSJwUq6KJUzZv0u49FBA2L4C8Vd3NVo8Cg@mail.gmail.com> (raw)
In-Reply-To: <CAMuHMdVUBgG0EFB16OxHisbxx-sBvDKvBPNZdpyDnmBrnX4ptQ@mail.gmail.com>

On Mon, Jun 29, 2026 at 4:58 PM Geert Uytterhoeven <geert@linux-m68k.org> wrote:
>
> Hi Bartosz,
>
> On Mon, 29 Jun 2026 at 16:07, Bartosz Golaszewski <brgl@kernel.org> wrote:
> > On Mon, 29 Jun 2026 15:51:31 +0200, Geert Uytterhoeven
> > <geert@linux-m68k.org> said:
> > > On Mon, 29 Jun 2026 at 13:29, Bartosz Golaszewski
> > > <bartosz.golaszewski@oss.qualcomm.com> wrote:
> > >> Describe the SGMII/SerDes PHY present on the Qualcomm sa8255p platforms.
> > >> This is essentially the same hardware as sa8775p rev3 but the PHY is
> > >> managed by firmware over SCMI.
> > >
> > > So why can't it be reuse the DT bindings, and be compatible with
> > > qcom,sa8775p-dwmac-sgmii-phy?
> > >
> > >> Signed-off-by: Bartosz Golaszewski <bartosz.golaszewski@oss.qualcomm.com>
> > >
> > >> --- /dev/null
> > >> +++ b/Documentation/devicetree/bindings/phy/qcom,sa8255p-dwmac-sgmii-phy.yaml
> > >
> > >> +  power-domains:
> > >> +    maxItems: 1
> > >> +
> > >> +  power-domain-names:
> > >> +    items:
> > >> +      - const: serdes
> > >
> > >> +examples:
> > >> +  - |
> > >> +    phy@8901000 {
> > >> +        compatible = "qcom,sa8255p-dwmac-sgmii-phy";
> > >> +        reg = <0x08901000 0xe10>;
> > >> +        #phy-cells = <0>;
> > >> +        power-domains = <&scmi7_dvfs 0>;
> > >> +        power-domain-names = "serdes";
> > >
> > > Ah, this uses power-domains, while the existing bindings for
> > > qcom,sa8775p-dwmac-sgmii-phy use a clock.
> > > I guess the clock is the correct hardware description?
> > >
> > > Adding to my list of examples for backing a hardware-to-SCMI remapping
> > > driver...
> > >
> >
> > Russell King asked me to put the PHY logic for SCMI pm domains into the PHY
> > driver instead of the MAC driver where it was previously. Instead of cramming
> > both HLOS and firmware handling into the same driver, I figured it makes more
> > sense to have a dedicated, cleaner driver as the two share very little code (if
> > any).
>
> I think you are mixing up DT bindings and driver implementation?
>

Ah indeed, but the bindings don't share a lot of content either.

Bartosz

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