回覆: 回覆: [PATCH v2 05/10] ARM: dts: aspeed: system1: Add RGMII support

[Andrew Lunn]

> Do we need updates on this description. It doesn't talk about external PCB
> level delays?
> 
> https://github.com/torvalds/linux/blob/master/Documentation/devicetree/bindings/net/ethernet-controller.yaml#L77-L90
> 
> This is what you explained:
> 
> MAC driver reads following phy-mode from device tree. 95% of mac driver
> directly
>  pass it to PHY through phy_connect.
> 
> rgmii - PCB has long clock lines so delay is added by PCB
>         On this mode PHY does nothing.
> rgmii-id - PCB doesn't add delay. Either MAC or PHY needs to add the delay
>            Add delays in both directions. Some PHY may not add delay in that
>            case MAC needs to add the delay mask rgmii-id to rgmii.
> rgmii-rxid - If there is an extra long TX clock line, but not RX clock,
>              you would use rgmii-rxid
> rgmii-txid - When there is an extra long RX clock line on the PCB, but not
>              the TX clock line, you would use rgmii-txid

The documentation is not great, that has been said a few times.  What
is described here is the view from the PHY, which is not ideal.

      # RX and TX delays are added by the MAC when required
      - rgmii