Hi Andrew Lunn,
Thanks for the feedback.
> Subject: Re: [PATCH/RFC 2/2] ravb: Add GbEthernet driver support
>
> On Wed, Jul 14, 2021 at 05:01:34PM +0000, Biju Das wrote:
> > Hi Andrew Lunn,
> >
> > Thanks for the feedback.
> >
> > > Subject: Re: [PATCH/RFC 2/2] ravb: Add GbEthernet driver support
> > >
> > > > + if (priv->phy_interface == PHY_INTERFACE_MODE_RGMII_ID) {
> > > > + ravb_write(ndev, ravb_read(ndev, CXR31)
> > > > + | CXR31_SEL_LINK0, CXR31);
> > > > + } else {
> > > > + ravb_write(ndev, ravb_read(ndev, CXR31)
> > > > + & ~CXR31_SEL_LINK0, CXR31);
> > > > + }
> > >
> > > You need to be very careful here. What value is passed to the PHY?
> >
> > PHY_INTERFACE_MODE_RGMII is the value passed to PHY.
>
> In all four cases? So if DT contains rgmii-txid, or rgmii-rxid, the
> requested delay will not happen in either the MAC or the PHY?
OK, it is my mistake. I specified "rgmii" in DT.
Without phy delays (rx and tx) ethernet won't work. Will fix it as "rgmii-id" in dt.
The above register(In-band Status set register) is basically used for selecting the link.
>
> In general in Linux, MAC drivers don't add any delays, and request the PHY
> to do it. There are some MAC drivers which do it differently, they add the
> delays, but that is uncommon. So unless you have a good reason not to, i
> would suggest you leave the PHY to do the delays.
OK.
Regards,
Biju
