On Sat, 17 Feb 2024 13:14:29 +0100 Oleksij Rempel <o.rempel@xxxxxxxxxxxxxx> 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"; This property should be on the PD side. Isn't it better to name it "polarity-provided" for each PSE PIs binding? What do you think? We agreed that it is mainly for ethtool to show the polarity of a PI, right? Regards, -- Köry Maincent, Bootlin Embedded Linux and kernel engineering https://bootlin.com