Re: [PATCH] arm64: dts: rockchip: use MAC TX delay for ROCK 4D
From: Andrew Lunn <andrew@lunn.ch>
Date: 2025-07-24 15:51:22
Also in:
linux-arm-kernel, linux-rockchip, lkml
quoted hunk ↗ jump to hunk
&gmac0 { clock_in_out = "output"; phy-handle = <&rgmii_phy0>; - phy-mode = "rgmii-id"; + phy-mode = "rgmii-rxid"; pinctrl-names = "default"; pinctrl-0 = <ð0m0_miim ð0m0_tx_bus2@@ -246,6 +246,8 @@ ð0m0_rgmii_clk ð0m0_rgmii_bus ðm0_clk0_25m_out>; status = "okay"; + tx_delay = <0x20>; + rx_delay = <0x00>;
What does 0x20 mean? Is it less than 2ns, or greater than 2ns? Have you tried "rgmii-id" and small values for tx_delay? If the hardware needs 2.1ns, for example, the MAC could add 0.1ns and the PHY adds the default 2ns. That would allow you to conform to the DT binding. What PHY is this? Have you looked it you can control the delays the PHY adds? If you actually need a delay of 1.9ns, maybe the PHY can be configured to do this? That would also allow you to conform to the DT binding. Andrew