Re: [RFC PATCH v2 4/8] net: sparx5: add port module support

Andrew Lunn
2020-12-22T15:09:32Z

> > > +static int sparx5_port_verify_speed(struct sparx5 *sparx5,
> > > + struct sparx5_port *port,
> > > + struct sparx5_port_config *conf)
> > > +{
> > > + case PHY_INTERFACE_MODE_SGMII:
> > > + if (conf->speed != SPEED_1000 &&
> > > + conf->speed != SPEED_100 &&
> > > + conf->speed != SPEED_10 &&
> > > + conf->speed != SPEED_2500)
> > > + return sparx5_port_error(port, conf,
> > > SPX5_PERR_SPEED);
> >
> > Is it really SGMII over clocked at 2500? Or 2500BaseX?
>
> Yes the SGMII mode in the serdes driver is overclocked.
> Nothing in the switch driver needs changing when changing between
> speeds 1G/2G5.

So it continues to use the SGMII inband signalling?

There is a lot of confusion in this area, but SGMII inband signalling
overclocked does not make much sense. So it is more likely to be using
2500BaseX.

Andrew