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Date: Wed, 3 Apr 2024 11:15:48 +0200
From: Kory Maincent <kory.maincent@bootlin.com>
To: Rob Herring <robh@kernel.org>
Cc: "David S. Miller" <davem@davemloft.net>, Eric Dumazet
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Subject: Re: [PATCH net-next v6 11/17] dt-bindings: net: pse-pd: Add another
 way of describing several PSE PIs
Message-ID: <20240403111548.30e780b5@kmaincent-XPS-13-7390>
In-Reply-To: <20240402132637.GA3744978-robh@kernel.org>
References: <20240326-feature_poe-v6-0-c1011b6ea1cb@bootlin.com>
	<20240326-feature_poe-v6-11-c1011b6ea1cb@bootlin.com>
	<20240402132637.GA3744978-robh@kernel.org>
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On Tue, 2 Apr 2024 08:26:37 -0500
Rob Herring <robh@kernel.org> wrote:

> > +          pairset-names:
> > +            $ref: /schemas/types.yaml#/definitions/string-array
> > +            description:
> > +              Names of the pairsets as per IEEE 802.3-2022, Section
> > 145.2.4.
> > +              Valid values are "alternative-a" and "alternative-b". Ea=
ch
> > name =20
>=20
> Don't state constraints in prose which are defined as schema=20
> constraints.

Ok, I will remove the line.

> > +          pairsets:
> > +            $ref: /schemas/types.yaml#/definitions/phandle-array
> > +            description:
> > +              List of phandles, each pointing to the power supply for =
the
> > +              corresponding pairset named in 'pairset-names'. This pro=
perty
> > +              aligns with IEEE 802.3-2022, Section 33.2.3 and 145.2.4.
> > +              PSE Pinout Alternatives (as per IEEE 802.3-2022 Table
> > 145\u20133)
> > +
> > |-----------|---------------|---------------|---------------|----------=
-----|
> > +              | Conductor | Alternative A | Alternative A | Alternativ=
e B
> > | Alternative B |
> > +              |           |    (MDI-X)    |     (MDI)     |      (X)
> > |      (S)      |
> > +
> > |-----------|---------------|---------------|---------------|----------=
-----|
> > +              | 1         | Negative VPSE | Positive VPSE | \u2014
> >     | \u2014             |
> > +              | 2         | Negative VPSE | Positive VPSE | \u2014
> >     | \u2014             |
> > +              | 3         | Positive VPSE | Negative VPSE | \u2014
> >     | \u2014             |
> > +              | 4         | \u2014             | \u2014             |
> > Negative VPSE | Positive VPSE |
> > +              | 5         | \u2014             | \u2014             |
> > Negative VPSE | Positive VPSE |
> > +              | 6         | Positive VPSE | Negative VPSE | \u2014
> >     | \u2014             |
> > +              | 7         | \u2014             | \u2014             |
> > Positive VPSE | Negative VPSE |
> > +              | 8         | \u2014             | \u2014             |
> > Positive VPSE | Negative VPSE |
> > +            minItems: 1
> > +            maxItems: 2 =20
>=20
> "pairsets" does not follow the normal design pattern of foos, foo-names,=
=20
> and #foo-cells. You could add #foo-cells I suppose, but what would cells=
=20
> convey? I don't think it's a good fit for what you need.
>=20
> The other oddity is the number of entries and the names are fixed. That=20
> is usually defined per consumer.=20

Theoretically if the RJ45 port binding was supported it would make more sen=
se,
but in reality it's not feasible as the PSE controller need this information
in its init process.
The PSE controller reset all its port to apply a configuration so we can't =
do
it when the consumer (RJ45) probe. It would reset the other ports if one
consumer is probed later in the process.

> As each entry is just a power rail, why can't the regulator binding be=20
> used here?

Olekisj already answered about it.
PSE PI is like a regulator but with few different features and more informa=
tion
like the pinout and the polarity, so we could not really fully rely on the
regulator binding style.

> > +
> > +          polarity-supported:
> > +            $ref: /schemas/types.yaml#/definitions/string-array
> > +            description:
> > +              Polarity configuration supported by the PSE PI pairsets.
> > +            minItems: 1
> > +            maxItems: 4
> > +            items:
> > +              enum:
> > +                - MDI-X
> > +                - MDI
> > +                - X
> > +                - S
> > +
> > +          vpwr-supply:
> > +            description: Regulator power supply for the PSE PI. =20
>=20
> I don't see this being used anywhere.

Right, I forgot to add it to the PD692x0 and TPS23881 binding example!

Regards,
--=20
K=C3=B6ry Maincent, Bootlin
Embedded Linux and kernel engineering
https://bootlin.com