Re: [PATCH v5 2/7] dt-bindings: net: amlogic,meson-dwmac: add amlogic,t7-dwmac

[Chuan Liu]

Hi Lucas,

On 11/9/2026 11:43 PM, Lucas Tanure wrote:
> [ EXTERNAL EMAIL ]
>
> On Fri, Nov 6, 2026 at 3:16 AM Chuan Liu <chuan.liu@xxxxxxxxxxx> wrote:
> > Hi Krzysztof, Lucas,
> >
> > On 11/5/2026 7:57 PM, Krzysztof Kozlowski wrote:
> > > [ EXTERNAL EMAIL ]
> > >
> > > On Tue, Nov 03, 2026 at 04:37:10PM +0000, Lucas Tanure wrote:
> > > > Assisted-by: LLM
> > >
> > > Drop this one.
> > >
> > > > Signed-off-by: Lucas Tanure <tanure@xxxxxxxxx>
> > > > ---
> > > >    .../bindings/net/amlogic,meson-dwmac.yaml     | 59 +++++++++++++++++++
> > > >    1 file changed, 59 insertions(+)
> > > >
> > > > diff --git a/Documentation/devicetree/bindings/net/amlogic,meson-dwmac.yaml b/Documentation/devicetree/bindings/net/amlogic,meson-dwmac.yaml
> > > > index e769c9bb70d8..6de013e3e8f6 100644
> > > > --- a/Documentation/devicetree/bindings/net/amlogic,meson-dwmac.yaml
> > > > +++ b/Documentation/devicetree/bindings/net/amlogic,meson-dwmac.yaml
> > > > @@ -23,6 +23,7 @@ select:
> > > >              - amlogic,meson-gxbb-dwmac
> > > >              - amlogic,meson-axg-dwmac
> > > >              - amlogic,meson-g12a-dwmac
> > > > +          - amlogic,t7-dwmac
> > > >      required:
> > > >        - compatible
> > > >
> > > > @@ -57,6 +58,59 @@ allOf:
> > > >                - const: clkin1
> > > >                - const: timing-adjustment
> > > >
> > > > +  - if:
> > > > +      properties:
> > > > +        compatible:
> > > > +          contains:
> > > > +            const: amlogic,t7-dwmac
> > > > +    then:
> > > > +      properties:
> > > > +        clocks:
> > > > +          items:
> > > > +            - description: GMAC main clock
> > > > +            - description: First parent clock of the internal mux
> > > > +            - description: Second parent clock of the internal mux
> > > > +            - description:
> > > > +                clock of the pipeline stage inserted in the bus path between
> > > > +                the controller and the DRAM. Without it, the controller cannot
> > > > +                complete DMA transfers.
> > > > +            - description:
> > > > +                clock of the register block holding PRG_ETH0 and PRG_ETH1.
> > > > +                Without it, the block reads as zero and ignores writes.
> > >
> > > This sounds like you take clock from other block. That's wrong, that
> > > device should take its own clock.
> >
> > I see that the clock in the dts patch corresponds to <&clkc_periphs
> > CLKID_SYS_ETHPHY>. This clock provides the working clock for the APB Bus
> > of the ETH PHY controller, and this clock will affect the register
> > reading and writing of the ETH PHY (including the ETH_PLL). See section
> > 15.3.4.2 RegisterDescription in A311D2 Datasheet for details.
>
> Thanks. That section is the PHY block at 0xfe028000, the region of the
> mdio multiplexer node. The registers in this description are PRG_ETH0
> and PRG_ETH1 in eth_top at 0xfe024000. On the VIM4 the same gate feeds
> them too: with it off they read as zero and ignore writes. My datasheet
> revisions do not say which clock feeds eth_top. Can you confirm it is
> this one?

The information I can confirm is:
  - The base address of eth_phy is 0xfe028000, and its corresponding 
APB clock is <&clkc_periphs CLKID_SYS_ETHPHY>.
  - The base address of eth_top is 0xfe024000, and the base address of 
eth_mac is 0xfdc00000; their corresponding APB clock is <&clkc_periphs 
CLKID_SYS_ETH>.

The CPU reads and writes the registers of these peripheral controllers 
(or Processing Units) via the APB. Consequently, the registers of these 
controllers cannot be read and written properly if the corresponding APB 
clock (sys_clk/clk81) is not enabled.

> Thanks,
> Lucas
>
> > > > +
> > > > +        clock-names:
> > > > +          items:
> > > > +            - const: stmmaceth
> > > > +            - const: clkin0
> > > > +            - const: clkin1
> > > > +            - const: pipeline
> > > > +            - const: pclk
> > > > +
> > > > +        # The PHY adds the 2ns RGMII delays, see ethernet-controller.yaml.
> > > > +        # The RX delay line of this glue is fine tuning in 200ps steps,
> > > > +        # added on top of what phy-mode describes. The TX side has no fine
> > > > +        # tuning: its only step is a quarter of the clock period, the full
> > > > +        # 2ns at 1Gbit/s, so the TX property is not accepted.
> > > > +        tx-internal-delay-ps: false
> > > > +
> > > > +        # Deprecated: new SoCs use the standard *-internal-delay-ps
> > > > +        # properties instead.
> > > > +        amlogic,tx-delay-ns: false
> > > > +        amlogic,rx-delay-ns: false
> > > > +
> > > > +  # Delay definitions for Meson8b and newer
> > > > +  - if:
> > > > +      properties:
> > > > +        compatible:
> > > > +          contains:
> > > > +            enum:
> > > > +              - amlogic,meson8b-dwmac
> > > > +              - amlogic,meson8m2-dwmac
> > > > +              - amlogic,meson-gxbb-dwmac
> > > > +              - amlogic,meson-axg-dwmac
> > > > +              - amlogic,meson-g12a-dwmac
> > > > +    then:
> > > > +      properties:
> > > >            amlogic,tx-delay-ns:
> > > >              enum: [0, 2, 4, 6]
> > > >              default: 2
> > > > @@ -106,6 +160,7 @@ allOf:
> > > >              contains:
> > > >                enum:
> > > >                  - amlogic,meson-g12a-dwmac
> > > > +              - amlogic,t7-dwmac
> > > >        then:
> > > >          properties:
> > > >            rx-internal-delay-ps:
> > > > @@ -142,6 +197,10 @@ properties:
> > > >          - items:
> > > >              - const: amlogic,meson6-dwmac
> > > >              - const: snps,dwmac
> > > > +      - items:
> > > > +          - const: amlogic,t7-dwmac
> > > > +          - const: snps,dwmac-5.10a
> > > > +          - const: snps,dwmac
> > >
> > > I see no such hunk in the code, so not sure how to review this.
> > >
> > > Best regards,
> > > Krzysztof
> > >
> > >
> > > _______________________________________________
> > > linux-amlogic mailing list
> > > linux-amlogic@xxxxxxxxxxxxxxxxxxx
> > > http://lists.infradead.org/mailman/listinfo/linux-amlogic
> >
> > --
> > Best regards,
> > Chuan

--
Best regards,
Chuan