Re: [PATCH v8 net-next 01/10] dt-bindings: net: dsa: dt bindings for microchip lan937x

[Florian Fainelli]

On 2/9/2022 3:58 AM, Prasanna Vengateshan wrote:
> On Mon, 2022-02-07 at 18:53 -0800, Florian Fainelli wrote:
> > EXTERNAL EMAIL: Do not click links or open attachments unless you know the
> > content is safe
> >
> > On 2/7/2022 9:21 AM, Prasanna Vengateshan wrote:
> > > Documentation in .yaml format and updates to the MAINTAINERS
> > > Also 'make dt_binding_check' is passed.
> > >
> > > RGMII internal delay values for the mac is retrieved from
> > > rx-internal-delay-ps & tx-internal-delay-ps as per the feedback from
> > > v3 patch series.
> > > https://lore.kernel.org/netdev/20210802121550.gqgbipqdvp5x76ii@skbuf/
> > >
> > > It supports only the delay value of 0ns and 2ns.
> > >
> > > Signed-off-by: Prasanna Vengateshan <prasanna.vengateshan@xxxxxxxxxxxxx>
> > > Reviewed-by: Rob Herring <robh@xxxxxxxxxx>
> > > ---
> > >    .../bindings/net/dsa/microchip,lan937x.yaml   | 179 ++++++++++++++++++
> > >    MAINTAINERS                                   |   1 +
> > >    2 files changed, 180 insertions(+)
> > >    create mode 100644
> > > Documentation/devicetree/bindings/net/dsa/microchip,lan937x.yaml
> > >
> > > +    maxItems: 1
> > > +
> > > +  mdio:
> > > +    $ref: /schemas/net/mdio.yaml#
> > > +    unevaluatedProperties: false
> >
> > This should be moved to dsa.yaml since this is about describing the
> > switch's internal MDIO bus controller. This is applicable to any switch,
> > really.
>
> Thanks for your review and feedback. Do you mean that 'mdio' to be added in
> dsa.yaml instead adding here?

Yes indeed, since this is a common property of all DSA switches, it can 
be defined or not depending on whether the switch does have an internal 
MDIO bus controller or not.

> > > +
> > > +patternProperties:
> > > +  "^(ethernet-)?ports$":
> > > +    patternProperties:
> > > +      "^(ethernet-)?port@[0-7]+$":
> > > +        allOf:
> > > +          - if:
> > > +              properties:
> > > +                phy-mode:
> > > +                  contains:
> > > +                    enum:
> > > +                      - rgmii
> > > +                      - rgmii-rxid
> > > +                      - rgmii-txid
> > > +                      - rgmii-id
> > > +            then:
> > > +              properties:
> > > +                rx-internal-delay-ps:
> > > +                  $ref: "#/$defs/internal-delay-ps"
> > > +                tx-internal-delay-ps:
> > > +                  $ref: "#/$defs/internal-delay-ps"
> >
> > Likewise, this should actually be changed in ethernet-controller.yaml
>
> There is *-internal-delay-ps property defined for mac in ethernet-
> controller.yaml. Should that be changed like above?

It seems to me that these properties override whatever 'phy-mode' 
property is defined, but in premise you are right that this is largely 
applicable to RGMII only. I seem to recall that the QCA8K driver had 
some sort of similar delay being applied even in SGMII mode but I am not 
sure if we got to the bottom of this.

Please make sure that this does not create regressions for other DTS in 
the tree before going with that change in ethernet-controller.yaml.

Thanks!
--
Florian