Re: [PATCH net-next v4 1/4] dt-bindings: mfd: x-powers: Add AC200

[James Hilliard]

On Sun, Aug 9, 2026 at 9:34 AM Andrew Lunn <andrew@xxxxxxx> wrote:
>
> > +description:
> > +  The AC200 is a mixed-signal companion IC containing audio, video, RTC and
> > +  Fast Ethernet PHY functions. Its control registers are accessed over I2C.
> > +
> > +properties:
> > +  compatible:
> > +    const: x-powers,ac200
> > +
> > +  reg:
> > +    maxItems: 1
> > +
> > +  clocks:
> > +    maxItems: 1
> > +    description:
> > +      AC200 input clock. When using the Ethernet PHY, its configured rate must
> > +      be 24 or 27 MHz, matching the rates encoded by the documented EPHY clock
> > +      selector.
>
> What is the scope of this clock. Is the PHY the only consumer?

No. This is the AC200's external CKI system-clock input, not an
EPHY-local clock. SYS_CLK_CTL selects that input as the source of the
chip-wide SYS_CLK, and the audio, EPHY and TVE blocks have separate
downstream clock gates. The audio clock tree also uses the 24 MHz
system clock.

The AC200 core therefore owns and enables this shared input. The EPHY
driver only checks its rate in order to program the EPHY-specific
CLK_SEL bit.

> > +  ephy-vcc-supply:
> > +    description: 3.3 V supply for the Ethernet PHY analog front end
>
> This sounds to be specific to the PHY, so the PHY driver should be the
> consumer, not the MFD as a whole. That then would allow the PHY to
> perform power management, turn the regulator off when the link is
> admin down, so suspended.

EPHY_VCC is specific to the Ethernet PHY, even when a board connects it
to the same physical 3.3 V regulator as other AC200 supply pins. The
regulator core will retain the shared rail while any other consumer
still has it enabled.

For v5 I have removed ephy-vcc-supply from the AC200 MFD node and moved
the supply to the Ethernet PHY package. Both variants now use a common
vcc-supply property, connected to EPHY_VCC on AC200 and VCC1 on AC300.

>
>         Andrew