Re: [PATCH v2 09/15] dt-bindings: iio: adc: adi,ad4134: Document SPI connection mode

[Rob Herring]

On Thu, Sep 17, 2026 at 04:30:39AM +0100, Jonathan Cameron wrote:
> On Wed, 16 Sep 2026 11:00:25 -0500
> Rob Herring <robh@xxxxxxxxxx> wrote:
> 
> > On Tue, Sep 15, 2026 at 04:14:44PM -0300, Marcelo Schmitt wrote:
> > > Document how AD4134 chips are connected to the host SPI controller
> > > according to different wiring configurations.
> > > 
> > > Signed-off-by: Marcelo Schmitt <marcelo.schmitt@xxxxxxxxxx>
> > > ---
> > > Change log v1 -> v2:
> > > - Set default for adi,spi-mode property.
> > > - Added '#daisy-chained-devices' property.
> > > - Documented constraints for adi,spi-mode + #daisy-chained-devices combinations.
> > > 
> > >  .../bindings/iio/adc/adi,ad4134.yaml          | 51 ++++++++++++++++---
> > >  1 file changed, 44 insertions(+), 7 deletions(-)
> > > 
> > > diff --git a/Documentation/devicetree/bindings/iio/adc/adi,ad4134.yaml b/Documentation/devicetree/bindings/iio/adc/adi,ad4134.yaml
> > > index ea6d7e026419..012e09decf7a 100644
> > > --- a/Documentation/devicetree/bindings/iio/adc/adi,ad4134.yaml
> > > +++ b/Documentation/devicetree/bindings/iio/adc/adi,ad4134.yaml
> > > @@ -131,6 +131,26 @@ properties:
> > >      enum: [ free-running, gated ]
> > >      default: gated
> > >  
> > > +  adi,spi-mode:
> > > +    $ref: /schemas/types.yaml#/definitions/string
> > > +    enum: [ no-cs, 4-wire, one-channel-chain, two-channel-chain ]
> > > +    default: no-cs
> > > +    description: |
> > > +      This property indicates the SPI wiring configuration.
> > > +      * no-cs: The datasheet calls this "minimum I/O mode". In this mode, the CS
> > > +        line is not used (tied to GND).
> > > +      * 4-wire: Specifies a conventional SPI wiring configuration.  
> > 
> > Absence of this property should be conventional mode.
> Hi Rob,
> 
> Unfortunately we missed this in the binding originally so we are left with the default
> of what the driver did at the time.
> 
> I wouldn't be against merging a change in that default as a fix though if we
> don't think this is yet in heavy use (merged in 7.0, but given not a complete
> feature set yet, maybe?)

Ok, it's fine then. Just make sure the commit msg has this detail.

Rob