On 2024-05-08 02:35:27 +0200, Andrew Lunn wrote: > > > This looks wrong. You should be applying delays for rgmii-id and > > > rgmii-rxid. Plain rgmii means no delays are required, because the > > > board has extra long clock lines. Same for TX delays, only for > > > rgmii-tx or rgmii-id. > > > > This confuses me a bit, from the bindings in ethernet-controller.yaml I > > get this the other way around, > > > > # RX and TX delays are added by the MAC when required > > - 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-id > > > > # RGMII with internal RX delay provided by the PHY, the MAC > > # should not add an RX delay in this case > > - rgmii-rxid > > > > # RGMII with internal TX delay provided by the PHY, the MAC > > # should not add an TX delay in this case > > - rgmii-txid > > > > The way I understand it is that if if the phy-mode is 'rgmii' the MAC > > shall apply delays if requested and only if the phy-mode is 'rgmii-id' > > shall the MAC completely ignore the delays and let the PHY handle it. > > It is confusing, and made worse by you doing different to normal and > implementing it in the MAC, not the PHY. > > 1% of boards use extra long clock lines, so don't need additional > delays. They use 'rgmii'. There is at least one board i know of which > has one extra long clock line, and one normal length clock line. That > board uses 'rgmii-txid', or 'rgmii-rxid', i don't remember which. The > other 98% of boards should be using 'rgmii-id', indicating something > needs to insert delays. Of those 98%, the vast majority pass phy-mode > straight to the PHY, and the PHY added delays in both the Rx and Tx > clock. If the MAC decides to add the delays, and it is 'rgmii-id', it > should enable delays for both clock lines, and pass 'rgmii' to the > PHY. In the unlikely event somebody builds one of those 2% boards > using the MAC, you need to enable just Rx delays, or just Tx delays, > or maybe no delay at all, because of extra long clock lines. But you > should still be passing 'rgmii' to the PHY. Thanks for your patience and this explanation, I understand now. > > > Just so I understand correctly, if the phy-mode is A I should pass B to > > of_phy_connect() if I apply the delays in the MAC. > > > > A B > > rgmii rgmii-id > > rgmii-id rgmii > > rgmii-rxid rgmii-txid > > rgmii-txid rgmii-rxid > > Nope. Since the MAC is doing the delay, you always pass rgmii to the > PHY. A determines what, if any, delays the MAC adds. > > Andrew -- Kind Regards, Niklas Söderlund
