[U-Boot] [PATCH v3 0/2] sunxi: Enable EMAC on A83T boards using Realtek RTL8211E PHY

[Chen-Yu Tsai]

On Fri, May 3, 2019 at 8:15 PM Jagan Teki <jagan at amarulasolutions.com> wrote:
>
> On Fri, May 3, 2019 at 3:31 PM Chen-Yu Tsai <wens at kernel.org> wrote:
> >
> > On Fri, May 3, 2019 at 5:49 PM Jagan Teki <jagan at amarulasolutions.com> wrote:
> > >
> > > On Fri, May 3, 2019 at 7:58 AM Chen-Yu Tsai <wens at kernel.org> wrote:
> > > >
> > > > From: Chen-Yu Tsai <wens at csie.org>
> > > >
> > > > Hi everyone,
> > > >
> > > > This series enables EMAC (Ethernet controller) on two A83T boards,
> > > > the Cubietruck Plus and Bananapi M3.
> > > >
> > > > This series is now based on sunxi/next, which has patches that convert
> > > > sun8i-emac to use the common CLK and DM_RESET framework.
> > > >
> > > > The two patches enable the sun8i-emac and Realtek PHY driver in their
> > >
> > > So, the U-Boot operates realtek than what Linux does via
> > > ethernet-phy-ieee802.3-c22 right? if someone add it in future it will
> > > override realtek since we have a dts compatible enabled it dts files
> > > already isn't it?
> >
> > What? No. The PHY vendor and model are automatically detected by reading
> > the standard registers in the PHY. The compatible string is only used to
> > determine how to access the registers. c22 vs c45 define different ways
> > of accessing registers, as well as a larger address space for c45.
> >
> > See https://www.totalphase.com/support/articles/200349206-MDIO-Background
> >
> > By reading the vendor and model IDs, the system, be it Linux or U-boot,
> > can then go through the list of registered PHY drivers to find a match,
> > or fall back to some generic implementation.
>
> Yes, I understand thanks.
>
> >
> > It used to be you needed to enable the Realtek driver for gigabit links
> > to work properly, but that seems to have been fixed. Nevertheless, having
> > the specific driver enabled is better.
>
> Ah.. this is what exactly I tried before in Linux since it doesn't
> enable default in sunxi_defconfig. on the other-hand the existing
> generic compatible is also working for gigabit links as well.

Yeah. My memories of it not working are from way back, before the whole
DM conversion even started.

I think it's still better to have the specific driver enabled though,
as the PHY has some vendor specific features or status flags.

ChenYu