[net-next PATCH v1 0/2] stmmac: dwmac-meson8b: configurable RGMII TX delay

[Måns Rullgård]

Sebastian Frias <sf84 at laposte.net> writes:

> On 24/11/16 19:55, Florian Fainelli wrote:
>> Le 24/11/2016 à 09:05, Martin Blumenstingl a écrit :
>>> Based on what I found it seems that rgmii-id, rgmii-txid and
>>> rgmii-rxid are supposed to be handled by the PHY.
>> 
>> Correct, the meaning of PHY_INTERFACE_MODE should be from the
>> perspective of the PHY device:
>> 
>> - PHY_INTERFACE_MODE_RGMII_TXID means that the PHY is responsible for
>> adding a delay when the MAC transmits (TX MAC -> PHY (delay) -> wire)
>> - PHY_INTERFACE_MODE_RGMII_RXID means that the PHY is responsible for
>> adding a delay when the MAC receives (RX MAC <- (delay) PHY) <- wire)
>> 
>
> Thanks for the explanation.
> Actually I had thought that the delay was to account for board routing
> (wires) between the MAC and the PHY.
> From your explanation it appears that the delay is to account for board
> routing (wires) between the PHY and the RJ45 socket.

The delay pertains to the RGMII link between MAC and PHY.  The external
connection is self-clocking.

-- 
Måns Rullgård