Re: [PATCH v2 1/2] dt-bindings: iio: adc: Add TI ADS1120 binding

[Ajith Anandhan]

On 11/18/25 5:49 AM, David Lechner wrote:
> On 11/15/25 12:31 PM, Jonathan Cameron wrote:
> > On Sun,  9 Nov 2025 19:41:18 +0530
> > Ajith Anandhan <ajithanandhan0406@xxxxxxxxx> wrote:
> >
> > > Add device tree binding documentation for the Texas Instruments
> > > ADS1120.
> > >
> > > The binding defines required properties like compatible, reg, and
> > > SPI configuration parameters.
> > >
> > > Signed-off-by: Ajith Anandhan <ajithanandhan0406@xxxxxxxxx>
> > > ---
> > >   .../bindings/iio/adc/ti,ads1120.yaml          | 109 ++++++++++++++++++
> > >   1 file changed, 109 insertions(+)
> > >   create mode 100644 Documentation/devicetree/bindings/iio/adc/ti,ads1120.yaml
> > >
> > > diff --git a/Documentation/devicetree/bindings/iio/adc/ti,ads1120.yaml b/Documentation/devicetree/bindings/iio/adc/ti,ads1120.yaml
> > > new file mode 100644
> > > index 000000000..2449094af
> > > --- /dev/null
> > > +++ b/Documentation/devicetree/bindings/iio/adc/ti,ads1120.yaml
> > >
> > > +
> > > +  vref-supply:
> > > +    description: |
> > > +      Optional external voltage reference. Can be connected to either
> > > +      REFP0/REFN0 or REFP1/REFN1 pins. If not supplied, the internal
> > > +      2.048V reference is used.
> > How do you know which set of inputs is used?  Looks like a register
> > needs to be programmed to pick between them.
> I would just make two supply properties for this, ref0-supply and ref1-supply


Hi Jonathan and David Thanks for the review,

That makes sense! I'll change the binding to use two separate properties:

       - ref0-supply: for REFP0/REFN0 pins

       - ref1-supply: for REFP1/REFN1 pins


> > > +
> > > +  ti,avdd-is-ref:
> > > +    type: boolean
> > > +    description: |
> > > +      If present, indicates that the AVDD supply voltage is of sufficient
> > > +      quality and stability to be used as the voltage reference instead of
> > > +      the internal reference. This allows the driver to select AVDD as the
> > > +      reference source for potentially better performance.
> > This one is interesting as I don't recall anyone arguing this made
> > sense before.  In what way better performance?  Are their boards out
> > there where this definitely makes sense to do?
> Seems harmless to have the property even if no one ever uses it. But I would
> be curious to know the answers to those questions too.


I included this property based on the datasheet mentioning AVDD as a 
possible reference source, butit doesn't claim this provides better 
performance, and I don't currently have a specific use case or hardware 
design that requires it.

How to proceed ? Need your valuable suggestions.


BR,

Ajith.

>