On Tue, Apr 15, 2025 at 12:18:01PM +0200, Matthias Schiffer wrote: > diff --git a/Documentation/devicetree/bindings/net/ethernet-controller.yaml b/Documentation/devicetree/bindings/net/ethernet-controller.yaml > index 45819b2358002..2ddc1ce2439a6 100644 > --- a/Documentation/devicetree/bindings/net/ethernet-controller.yaml > +++ b/Documentation/devicetree/bindings/net/ethernet-controller.yaml > @@ -74,19 +74,21 @@ properties: > - rev-rmii > - moca > > - # RX and TX delays are added by the MAC when required > + # RX and TX delays are part of the board design (through PCB traces). MAC > + # and PHY must not add delays. > - rgmii > > - # RGMII with internal RX and TX delays provided by the PHY, > - # the MAC should not add the RX or TX delays in this case > + # RGMII with internal RX and TX delays provided by the MAC or PHY. No > + # delays are included in the board design; this is the most common case > + # in modern designs. > - rgmii-id > > - # RGMII with internal RX delay provided by the PHY, the MAC > - # should not add an RX delay in this case > + # RGMII with internal RX delay provided by the MAC or PHY. TX delay is > + # part of the board design. > - rgmii-rxid > > - # RGMII with internal TX delay provided by the PHY, the MAC > - # should not add an TX delay in this case > + # RGMII with internal TX delay provided by the MAC or PHY. RX delay is > + # part of the board design. > - rgmii-txid > - rtbi > - smii Sorry, but I don't think this wording improves the situation - in fact, I think it makes the whole thing way more confusing. Scenario 1: I'm a network device driver author. I read the above, Okay, I have a RGMII interface, but I need delays to be added. I'll detect when RGMII-ID is used, and cause the MAC driver to add the delays, but still pass PHY_INTERFACE_MODE_RGMII_ID to phylib. Scenario 2: I'm writing a DT file for a board. Hmm, so if I specify rgmii because the delays are implemented in the traces, but I need to fine-tune them. However, the documentation says that delays must not be added by the MAC or the PHY so how do I adjust them. I know, I'll use rgmii-id because that allows delays! I suspect neither of these two are really want you mean, but given this wording, that's exactly where it leads - which is more confusion and less proper understanding. -- RMK's Patch system: https://www.armlinux.org.uk/developer/patches/ FTTP is here! 80Mbps down 10Mbps up. Decent connectivity at last!
