linux-kernel - RE: [EXT] Re: [PATCH v4 2/5] dt-bindings: i3c: Add NXP P3H2x4x i3c-hub support

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Message-ID:
 <GVXPR04MB97786A5E118F5D12A9BA591B998CA@GVXPR04MB9778.eurprd04.prod.outlook.com>
Date: Thu, 15 Jan 2026 12:21:10 +0000
From: Aman Kumar Pandey <aman.kumarpandey@....com>
To: Krzysztof Kozlowski <krzk@...nel.org>
CC: "linux-kernel@...r.kernel.org" <linux-kernel@...r.kernel.org>,
	"linux-i3c@...ts.infradead.org" <linux-i3c@...ts.infradead.org>,
	"alexandre.belloni@...tlin.com" <alexandre.belloni@...tlin.com>,
	"krzk+dt@...nel.org" <krzk+dt@...nel.org>, "robh@...nel.org"
	<robh@...nel.org>, "conor+dt@...nel.org" <conor+dt@...nel.org>,
	"devicetree@...r.kernel.org" <devicetree@...r.kernel.org>,
	"broonie@...nel.org" <broonie@...nel.org>, "lee@...nel.org" <lee@...nel.org>,
	Frank Li <frank.li@....com>, "lgirdwood@...il.com" <lgirdwood@...il.com>,
	Vikash Bansal <vikash.bansal@....com>, Priyanka Jain <priyanka.jain@....com>,
	Shashank Rebbapragada <shashank.rebbapragada@....com>
Subject: RE: [EXT] Re: [PATCH v4 2/5] dt-bindings: i3c: Add NXP P3H2x4x
 i3c-hub support


On Tue, Jan 13, 2026 at 01:45:26PM +0200, Aman Kumar Pandey wrote: 
> +https://eur01.safelinks.protection.outlook.com/?url=http%3A%2F%2Fdevi
> > +cetree.org%2Fschemas%2Fmfd%2Fnxp%2Cp3h2840-i3c-
> hub.yaml%23&data=05%7C
> >
> +02%7Caman.kumarpandey%40nxp.com%7C75a7d6f1f8b74fd3ac5808de5346
> 3133%7C
> >
> +686ea1d3bc2b4c6fa92cd99c5c301635%7C0%7C0%7C639039758104017624%7
> CUnkno
> >
> +wn%7CTWFpbGZsb3d8eyJFbXB0eU1hcGkiOnRydWUsIlYiOiIwLjAuMDAwM
> CIsIlAiOiJX
> >
> +aW4zMiIsIkFOIjoiTWFpbCIsIldUIjoyfQ%3D%3D%7C0%7C%7C%7C&sdata=Ze
> GSgy3cF
> > +whQbcO%2BserynVrrrqYGOIwBMgVjgdY25Lg%3D&reserved=0
> 
> This is not a MFD device. Place it in appropriate place, e.g. i2c or i3c
> controllers directory.
> 

Thanks for the review and the comment.

I would like to clarify why I modeled the P3H2840 as an MFD.
While the primary function of the chip is an I3C hub, this device also contains a programmable regulator which is exposed externally and can be used to power downstream devices on the board, not only the internal hub logic. This regulator has:
- Independent enable/disable control
- Independent voltage configuration

>From the board and hardware point of view, this block is not only a "hub-internal" power control, but a board-level power resource that other devices depend on. 
hub logic and the regulator block have distinct roles and different Linux subsystems (I3C hub vs regulator framework), I modeled this as an MFD with two child devices.

> > +$schema:
> >
 
> > +  cp0-supply:
> > +    description: Phandle to voltage regulator providing power to controller
> port 0.
> 
> s/handle to voltage regulator providing power// because it is completely
> redundant. Just say port 0 power supply.
>

Ok.... I'll update the description to just:

cp0-supply:
  description: Controller port 0 power supply.
cp1-supply:
  description: Controller port 1 power supply.
tp0145-supply:
 description: Target port 0/1/24/5 power supply.
tp2367-supply:
 description: Target port 2/3/6/7 power supply.

> > +
> > +  cp1-supply:
> > +    description: Phandle to voltage regulator providing power to controller
> port 1.
> > +
> > +  tp0145-supply: