Re: [RFC PATCH 6/6] arm64: dts: amlogic: t7: khadas-vim4: enable the ethernet port

From: Neil Armstrong <neil.armstrong@linaro.org>
To: Lucas Tanure <tanure@linux.com>,
	xianwei.zhao@amlogic.com, Andrew Lunn <andrew+netdev@lunn.ch>,
	"David S. Miller" <davem@davemloft.net>,
	Eric Dumazet <edumazet@kernel.org>,
	Jakub Kicinski <kuba@kernel.org>, Paolo Abeni <pabeni@redhat.com>,
	Rob Herring <robh@kernel.org>,
	Krzysztof Kozlowski <krzk+dt@kernel.org>,
	Conor Dooley <conor+dt@kernel.org>,
	Kevin Hilman <khilman@baylibre.com>,
	Jerome Brunet <jbrunet@baylibre.com>,
	Martin Blumenstingl <martin.blumenstingl@googlemail.com>,
	Maxime Chevallier <maxime.chevallier@bootlin.com>,
	Maxime Coquelin <mcoquelin.stm32@gmail.com>,
	Alexandre Torgue <alexandre.torgue@foss.st.com>
Cc: netdev@vger.kernel.org, devicetree@vger.kernel.org,
	linux-arm-kernel@lists.infradead.org,
	linux-amlogic@lists.infradead.org, linux-kernel@vger.kernel.org,
	linux-stm32@st-md-mailman.stormreply.com
Subject: Re: [RFC PATCH 6/6] arm64: dts: amlogic: t7: khadas-vim4: enable the ethernet port
Date: Sun, 4 Oct 2026 17:29:37 +0200	[thread overview]
Message-ID: <e27cd2c3-7fd6-4327-a84d-3f66d902f141@linaro.org> (raw)
In-Reply-To: <20261004144046.391444-7-tanure@linux.com>

On 10/4/26 16:40, Lucas Tanure wrote:
> The board carries a Realtek RTL8211F gigabit PHY on the external
> management bus, connected to the MAC over RGMII.
> 
> Enable the controller, hand it the ethernet pins and point it at the
> PHY. The clock delays RGMII needs are supplied by the MAC rather than
> the PHY: 2ns on transmit and 2000ps on receive, the values the vendor
> kernel programs.
> 
> The PHY interrupt output is wired to GPIOH_6, so describe it and let
> link changes be reported instead of polled. The PHY reset pin is driven
> by an RC network on the board, not by the SoC, so there is no reset line
> to describe.
> 
> Tested at 930Mbit/s sustained receive over a minute, with no MAC error
> counters moving in either direction.
> 
> Assisted-by: LLM
> Signed-off-by: Lucas Tanure <tanure@linux.com>
> ---
>   .../amlogic/amlogic-t7-a311d2-khadas-vim4.dts | 28 +++++++++++++++++++
>   1 file changed, 28 insertions(+)
> 
> diff --git a/arch/arm64/boot/dts/amlogic/amlogic-t7-a311d2-khadas-vim4.dts b/arch/arm64/boot/dts/amlogic/amlogic-t7-a311d2-khadas-vim4.dts
> index 0fa83362b417..5d0365ddde72 100644
> --- a/arch/arm64/boot/dts/amlogic/amlogic-t7-a311d2-khadas-vim4.dts
> +++ b/arch/arm64/boot/dts/amlogic/amlogic-t7-a311d2-khadas-vim4.dts
> @@ -14,6 +14,7 @@ / {
>   	compatible = "khadas,vim4", "amlogic,a311d2", "amlogic,t7";
>   
>   	aliases {
> +		ethernet0 = &ethmac;
>   		serial0 = &uart_a;
>   		mmc0 = &sd_emmc_c;
>   		mmc1 = &sd_emmc_b;
> @@ -256,6 +257,33 @@ xtal: xtal-clk {
>   	};
>   };
>   
> +&ethmac {
> +	status = "okay";
> +	pinctrl-0 = <&eth_pins>, <&eth_rgmii_pins>;
> +	pinctrl-names = "default";
> +
> +	/*
> +	 * The RGMII clock delays are added by the MAC, so the PHY is
> +	 * asked for the mode that adds none.
> +	 */
> +	phy-mode = "rgmii";
> +	phy-handle = <&external_phy>;
> +	amlogic,tx-delay-ns = <2>;
> +	rx-internal-delay-ps = <2000>;
> +};
> +
> +&ext_mdio {
> +	external_phy: ethernet-phy@0 {
> +		/* Realtek RTL8211FD-CG */
> +		reg = <0>;
> +		max-speed = <1000>;
> +
> +		interrupt-parent = <&gpio_intc>;
> +		/* RGMII_INT on GPIOH_6 */
> +		interrupts = <154 IRQ_TYPE_LEVEL_LOW>;
> +	};
> +};
> +
>   &i2c_m_ao_a {
>   	status = "okay";
>   	pinctrl-0 = <&i2c0_ao_d_pins>;

Reviewed-by: Neil Armstrong <neil.armstrong@linaro.org>

Thanks,
Neil

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