Re: [PATCH 0/3] arm64: dts: rockchip: Change gmac phy-mode to rgmii-id for rk3576 board
From: Andrew Lunn <andrew@lunn.ch>
Date: 2026-01-21 12:57:31
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linux-arm-kernel, linux-rockchip, lkml
On Wed, Jan 21, 2026 at 11:15:45AM +0800, Chaoyi Chen wrote:
From: Chaoyi Chen <redacted>
According to the description in the net documentation, PHY modes
"rgmii", "rgmii-rxid" and "rgmii-txid" modes require the clock signal
to be delayed on the PCB.
The Rockchip platform has long used the above mentioned PHY modes and
private delay prop to describe the internal IO delay settings of the
chip, which is inconsistent with what is described in the documentation.
Some background, for RK3576, you can assume that:
tx_delay_time(ns) = 0.0579 * delay_line_count + 0.105
Where did this formula come from? Is it in the datasheet.
Andrew