Re: [PATCH 1/2] dt-bindings: i2c: Add NXP PCA9641 I2C bus master arbiter

From: Conor Dooley

Date: Wed Sep 09 2026 - 06:01:59 EST


On Wed, Sep 09, 2026 at 07:25:38AM +0200, Peter Rosin wrote:
> Den Tue, Sep 08, 2026 at 06:47:01PM +0100, skrev Conor Dooley:
> > On Tue, Sep 08, 2026 at 06:01:45PM +0530, Shiv Prakash Gupta wrote:
> > > Add device tree binding schema for the NXP PCA9641 2-to-1 I2C bus
> > > master arbiter.
> > >
> > > The PCA9641 arbitrates between two upstream I2C masters competing for a
> > > single downstream slave bus using a lock/grant ownership model. The
> > > binding supports an optional 'interrupts' property for interrupt-assisted
> > > arbitration.
> > >
> > > Signed-off-by: Shiv Prakash Gupta <shivprakash.gupta@xxxxxxx>
> > > ---
>
> ...
>
> > > + i2c-arb:
> > > + type: object
> > > + $ref: /schemas/i2c/i2c-controller.yaml
> > > + unevaluatedProperties: false
> > > + description:
> > > + I2C bus node representing the downstream slave bus controlled by the
> > > + PCA9641. Downstream slave devices are declared as child nodes here.
> >
> > Why does this node need to exist? Can't the i2c-arbiter node itself
> > contain the child devices?
>
> For symmetry with the pre-existing I2C arbs, which all have the extra
> node for historical implementation reasons? I don't know if that's
> considered a valid reason? I prefer to have all arbs follow the same
> structure...

If this is just how these devices are described in general, I think
that's probably fine.

Acked-by: Conor Dooley <conor.dooley@xxxxxxxxxxxxx>
pw-bot: not-applicable

(Also, good to see you back active)

Cheers.,
Conor.

>
> The "documentation" describing common I2C arbitration details went missing
> here:
>
> https://lore.kernel.org/all/20230731163833.319258-1-krzysztof.kozlowski@xxxxxxxxxx/
>
> Cheers,
> Peter

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