Re: [PATCH 2/4] dt-bindings: net: dsa: document internal MDIO bus

Andrew Lunn
2023-08-14T13:10:03Z

> Ah okay. I didn't consider the switch architecture where the data interface
> of the PHY is connected to the switch, and the PHY management interface is
> connected to the mdio bus that the switch is connected to.

The generic Linux architecture for PHYs and binding them to a MAC via
a phandle allows the PHY to be on any MDIO bus anywhere. DSA has some
additional shortcuts to support 1:1 mapping if the switch has its own
MDIO bus, without describing it in DT, but this is just in addition to
the generic code.

> Not json-schema documentation, don't care about:
> - ar9331.txt
> - lan9303.txt
> - lantiq-gswip.txt
> - marvell.txt

The marvell switch can have up to 2 MDIO busses. If i remember
correctly, there is also one switch which has one MDIO bus per port.

Andrew