Re: [PATCH v12 2/2] arm: dts: aspeed: ventura: add Meta Ventura BMC

[PK Lee]

> > +&mac3 {
> > +     status = "okay";
> > +     phy-mode = "rmii";
> > +     pinctrl-names = "default";
> > +     pinctrl-0 = <&pinctrl_rmii4_default>;
> > +     fixed-link {
> > +             speed = <100>;
> > +             full-duplex;
> > +     };
>
> What is on the other end of this fixed link?

The other end of this fixed link is the CPU port of a Marvell 88E6393X
switch. We are using this switch in unmanaged mode rather than using
the DSA subsystem. Therefore, we use a fixed-link to force the mac3 to
100Mbps full-duplex RMII to match the CPU port configuration.

>
> > +};
> > +
> > +&mdio0 {
> > +     status = "okay";
> > +};
>
> If there are no devices on the bus, why enable it?

We intentionally enable it so user-space tools can access the switch
registers. I have added a comment in v13 to clarify this.

>
>    Andrew

P.K. Lee