On Wed, Feb 21, 2024 at 07:41:35AM -0700, Rob Herring wrote:
> On Sat, Feb 17, 2024 at 01:14:29PM +0100, Oleksij Rempel wrote:
> > On Thu, Feb 15, 2024 at 05:02:55PM +0100, Kory Maincent wrote:
> > > Add the PD692x0 I2C Power Sourcing Equipment controller device tree
> > > bindings documentation.
> > >
> > > This patch is sponsored by Dent Project <dentproject@xxxxxxxxxxxxxxxxxxx>.
> > >
> > > Signed-off-by: Kory Maincent <kory.maincent@xxxxxxxxxxx>
> > > ---
> > ...
> > > + pse_pis {
> > > + #address-cells = <1>;
> > > + #size-cells = <0>;
> > > +
> > > + pse_pi0: pse_pi@0 {
> > > + reg = <0>;
> > > + #pse-cells = <0>;
> > > + pairset-names = "alternative-a", "alternative-b";
> > > + pairsets = <&phys0>, <&phys1>;
> > > + };
> > > + pse_pi1: pse_pi@1 {
> > > + reg = <1>;
> > > + #pse-cells = <0>;
> > > + pairset-names = "alternative-a";
> > > + pairsets = <&phys2>;
> >
> > According to latest discussions, PSE PI nodes will need some
> > additional, board specific, information:
> > - this controller do not implements polarity switching, we need to know
> > what polarity is implemented on this board. The 802.3 spec provide not
> > really consistent names for polarity configurations:
> > - Alternative A MDI-X
> > - Alternative A MDI
> > - Alternative B X
> > - Alternative B S
> > The board may implement one of polarity configurations per alternative
> > or have additional helpers to switch them without using PSE
> > controller.
> > Even if specification explicitly say:
> > "The PD shall be implemented to be insensitive to the polarity of the power
> > supply and shall be able to operate per the PD Mode A column and the PD
> > Mode B column in Table 33–13"
> > it is possible to find reports like this:
> > https://community.ui.com/questions/M5-cant-take-reversed-power-polarity-/d834d9a8-579d-4f08-80b1-623806cc5070
> >
> > Probably this kind of property is a good fit:
> > polarity-supported = "MDI-X", "MDI", "X", "S";
>
> Where does that live? Looks like a property of the consumers defined in
> the provider. Generally, that's not the right way for DT.
This is property of PSE PI (Power Interface)
Ethernet PHY --\
PSE (provider) ----> PSE PI (consumer of multiple PSE's) ----> Physial port
PSE - provides power lines.
PSE PI - switches (or not) power lines in different configurations. This
is different part of the board/system. PSE PI can have combination or
one of following configurations: "MDI-X", "MDI", "X", "S";
This is not something what PSE actually do. PSE PI and PSE are described
in IEEE802.3 specification.
> I'll say it
> again, I think you should be expanding #pse-cells (>1), not getting rid
> of them (==0).
Did you took time to read my last explanation? Sorry for making it long
description, this topic is a bit complex.
Regards,
Oleksij
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