Re: [PATCH 2/2] dt-bindings: net: dsa: mediatek,mt7530: document MDIO-bus

[Arınç ÜNAL]

On 30.04.2023 15:44, Daniel Golle wrote:
> On Sun, Apr 30, 2023 at 03:34:43PM +0300, Arınç ÜNAL wrote:
> > On 30.04.2023 14:28, David Bauer wrote:
> > > Document the ability to add nodes for the MDIO bus connecting the
> > > switch-internal PHYs.
> >
> > This is quite interesting. Currently the PHY muxing feature for the MT7530
> > switch looks for some fake ethernet-phy definitions on the mdio-bus where
> > the switch is also defined.
> >
> > Looking at the binding here, there will be an mdio node under the switch
> > node. This could be useful to define the ethernet-phys for PHY muxing here
> > instead, so we don't waste the register addresses on the parent mdio-bus for
> > fake things. It looks like this should work right out of the box. I will do
> > some tests.
> >
> > Are there any examples as to what to configure on the switch PHYs with this
> > change?
> >
> > > Signed-off-by: David Bauer <mail@xxxxxxxxxxxxxxx>
> > > ---
> > >    .../devicetree/bindings/net/dsa/mediatek,mt7530.yaml        | 6 ++++++
> > >    1 file changed, 6 insertions(+)
> > >
> > > diff --git a/Documentation/devicetree/bindings/net/dsa/mediatek,mt7530.yaml b/Documentation/devicetree/bindings/net/dsa/mediatek,mt7530.yaml
> > > index e532c6b795f4..50f8f83cc440 100644
> > > --- a/Documentation/devicetree/bindings/net/dsa/mediatek,mt7530.yaml
> > > +++ b/Documentation/devicetree/bindings/net/dsa/mediatek,mt7530.yaml
> > > @@ -128,6 +128,12 @@ properties:
> > >          See Documentation/devicetree/bindings/regulator/mt6323-regulator.txt for
> > >          details for the regulator setup on these boards.
> > > +  mdio:
> > > +    $ref: /schemas/net/mdio.yaml#
> > > +    unevaluatedProperties: false
> > > +    description:
> > > +      Node for the internal MDIO bus connected to the embedded ethernet-PHYs.
> >
> > Please set this property as false for mediatek,mt7988-switch as it doesn't
> > use MDIO.
>
> Well, quite the opposite is true. This change is **needed** on MT7988 as
> the built-in 1GE PHYs of the MT7988 are connected to the (internal) MDIO
> bus of the switch. And they do need calibration data assigned as nvmem
> via device tree.
>
> tl;dr: Despite not being connected via MDIO itself also MT7988 exposes an
> internal MDIO bus for the switch PHYs.

Got it, thanks.

Arınç