Re: [RFC PATCH v2 1/7] net: stmmac: dwmac-meson8b: let the controller apply the RGMII delays

[Andrew Lunn]

On Wed, Oct 07, 2026 at 09:26:21AM +0100, Lucas Tanure wrote:
> RGMII needs a delay on each of its two clocks. A board can get it from
> the length of its tracks, from the PHY, or from the controller.
> "rgmii-id" in the device tree says the delay is added inside the chips
> but not which chip adds it, and the generic tx-internal-delay-ps and
> rx-internal-delay-ps properties name the controller.
> 
> This driver ignored those properties. In the "-id" modes it switched
> its own delays off and left the whole job to the PHY, so a board that
> asks the controller for one of them does not get it, and a board whose
> PHY cannot supply that delay has no usable link at all.

Linux currently has no PHY device which cannot add delays. So this is
pretty much a non issue.

       Andrew