RE: [PATCH v2 net-next 1/2] dt-bindings: net: tja11xx: add "nxp,rmii-refclk-out" property

[Wei Fang]

> -----Original Message-----
> From: Rob Herring <robh@xxxxxxxxxx>
> Sent: 2024年10月9日 23:12
> To: Wei Fang <wei.fang@xxxxxxx>
> Cc: davem@xxxxxxxxxxxxx; edumazet@xxxxxxxxxx; kuba@xxxxxxxxxx;
> pabeni@xxxxxxxxxx; krzk+dt@xxxxxxxxxx; conor+dt@xxxxxxxxxx;
> andrew@xxxxxxx; f.fainelli@xxxxxxxxx; hkallweit1@xxxxxxxxx; Andrei Botila
> (OSS) <andrei.botila@xxxxxxxxxxx>; linux@xxxxxxxxxxxxxxx;
> devicetree@xxxxxxxxxxxxxxx; linux-kernel@xxxxxxxxxxxxxxx;
> netdev@xxxxxxxxxxxxxxx; imx@xxxxxxxxxxxxxxx
> Subject: Re: [PATCH v2 net-next 1/2] dt-bindings: net: tja11xx: add
> "nxp,rmii-refclk-out" property
> 
> On Tue, Oct 08, 2024 at 03:07:07PM +0800, Wei Fang wrote:
> > Per the RMII specification, the REF_CLK is sourced from MAC to PHY or
> > from an external source. But for TJA11xx PHYs, they support to output
> > a 50MHz RMII reference clock on REF_CLK pin. Previously the
> > "nxp,rmii-refclk-in" was added to indicate that in RMII mode, if this
> > property is present, REF_CLK is input to the PHY, otherwise it is
> > output. This seems inappropriate now. Because according to the RMII
> > specification, the REF_CLK is originally input, so there is no need to
> > add an additional "nxp,rmii-refclk-in" property to declare that
> > REF_CLK is input.
> >
> > Unfortunately, because the "nxp,rmii-refclk-in" property has been
> > added for a while, and we cannot confirm which DTS use the TJA1100 and
> > TJA1101 PHYs, changing it to switch polarity will cause an ABI break.
> > But fortunately, this property is only valid for TJA1100 and TJA1101.
> > For TJA1103/TJA1104/TJA1120/TJA1121 PHYs, this property is invalid
> > because they use the nxp-c45-tja11xx driver, which is a different
> > driver from TJA1100/TJA1101. Therefore, for PHYs using nxp-c45-tja11xx
> > driver, add "nxp,rmii-refclk-out" property to support outputting RMII
> > reference clock on REF_CLK pin.
> >
> > Signed-off-by: Wei Fang <wei.fang@xxxxxxx>
> > ---
> > V2 changes:
> > 1. Change the property name from "nxp,reverse-mode" to
> > "nxp,phy-output-refclk".
> > 2. Simplify the description of the property.
> > 3. Modify the subject and commit message.
> > V3 changes:
> > 1. Keep the "nxp,rmii-refclk-in" property for TJA1100 and TJA1101.
> > 2. Rephrase the commit message and subject.
> > V3 changes:
> > 1. Change the property name from "nxp,phy-output-refclk" to
> > "nxp,rmii-refclk-out", which means the opposite of "nxp,rmii-refclk-in".
> > 2. Refactor the patch after fixing the original issue with this YAML.
> > ---
> >  .../devicetree/bindings/net/nxp,tja11xx.yaml   | 18 ++++++++++++++++++
> >  1 file changed, 18 insertions(+)
> >
> > diff --git a/Documentation/devicetree/bindings/net/nxp,tja11xx.yaml
> > b/Documentation/devicetree/bindings/net/nxp,tja11xx.yaml
> > index a754a61adc2d..1e688c7a497d 100644
> > --- a/Documentation/devicetree/bindings/net/nxp,tja11xx.yaml
> > +++ b/Documentation/devicetree/bindings/net/nxp,tja11xx.yaml
> > @@ -62,6 +62,24 @@ allOf:
> >              reference clock output when RMII mode enabled.
> >              Only supported on TJA1100 and TJA1101.
> >
> > +  - if:
> > +      properties:
> > +        compatible:
> > +          contains:
> > +            enum:
> > +              - ethernet-phy-id001b.b010
> > +              - ethernet-phy-id001b.b013
> > +              - ethernet-phy-id001b.b030
> > +              - ethernet-phy-id001b.b031
> > +
> > +    then:
> > +      properties:
> > +        nxp,rmii-refclk-out:
> > +          type: boolean
> > +          description: |
> 
> Don't need '|' if no formatting.
> 
> > +            Enable 50MHz RMII reference clock output on REF_CLK pin.
> This
> > +            property is only applicable to nxp-c45-tja11xx driver.
> 
> Reword this to not be about some driver.

Thanks, I will refine it
> 
> > +
> >  patternProperties:
> >    "^ethernet-phy@[0-9a-f]+$":
> >      type: object
> > --
> > 2.34.1
> >