Re: [PATCH 08/21] dt-bindings: mfd: x-powers: add AC200

On Tue, Aug 4, 2026 at 12:45 AM James Hilliard
<[email protected]> wrote:
>
> On Mon, Aug 3, 2026 at 7:18 AM Andrew Lunn <[email protected]> wrote:
> >
> > > +            ethernet-phy-control {
> > > +                compatible = "x-powers,ac200-ephy-ctl";
> > > +                nvmem-cells = <&ephy_calibration>;
> > > +                nvmem-cell-names = "calibration";
> > > +                phy-mode = "rmii";
> > > +            };
> >
> > What do you mean by an ethernet PHY control?
> >
> > I assume this is not an actual Ethernet PHY, but some control logic
> > around it? Where is the ethernet PHY itself?
>
> Correct, this is not the Ethernet PHY itself. It is the package-specific
> sideband control block that must be configured before the normal Clause 22
> PHY registers become usable. For AC200, this control block is accessed
> through the parent AC200 I2C regmap. For AC300, the equivalent control block
> is accessed through a separate non-PHY Clause 22 address.

Basically, all the PHY behavior that is normally configured using strapping
pins on a discrete PHY is done over this I2C channel.

> The actual Ethernet PHY is a separate device on the MAC's MDIO bus. The
> shared PHY driver for that device is added in patch 16:
>
> https://lore.kernel.org/linux-sunxi/[email protected]/
>
> The later board DTS patches instantiate it as an ethernet-phy node beneath
> the MAC's MDIO bus and reference the appropriate sideband control provider.
>
> >
> >        Andrew