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

[Ajith Anandhan <ajithanandhan0406@gmail.com>]

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@gmail.com> 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@gmail.com>
>>> ---
>>>   .../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.

>