Re: [PATCH net-next 1/6] dt-bindings: net: mediatek-dwmac: add support for MT8189 SoC

[Andrew Lunn <andrew@lunn.ch>]

> On Tue, 2026-07-07 at 14:42 +0200, Andrew Lunn wrote:
> > > +  - if:
> > > +      properties:
> > > +        compatible:
> > > +          contains:
> > > +            enum:
> > > +              - mediatek,mt8189-gmac
> > > +    then:
> > > +      properties:
> > > +        clocks:
> > > +          items:
> > > +            - description: MAC Main clock
> > > +            - description: PTP clock
> > > +            - description: RMII reference clock provided by MAC
> > 
> > Since this is a MAC, it sounds like it is consuming its own clock?
> 
> In the driver ([1]), this clock is described as being only used and
> needed in RMII when MAC provides the reference clock, and useless
> otherwise (RGMII/MII or RMII when PHY provides the reference clock).

So it sounds like this is a clock output, going to the PHY, as its
reference clock input. So ideally, the PHY should consume this clock,
not the MAC.

> Its use and configuration also depends on the "mediatek,rmii-clk-from-
> mac" vendor property ([2]) presence in devicetree.

This makes it sounds like it is historically wrong, and the patch is
just extending this to the new device.

Do you have a board using RMII? Can you list the clock in the PHY
node, not the MAC, and see if it still works?

Ideally, for a new device, we should not repeat past errors.

	 Andrew