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

[Peter Rosin <peda@lysator.liu.se>]

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@nxp.com>
> > ---

...

> > +  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...

The "documentation" describing common I2C arbitration details went missing
here:

https://lore.kernel.org/all/20230731163833.319258-1-krzysztof.kozlowski@linaro.org/

Cheers,
Peter