Re: [PATCH RFC 2/3] dt-bindings: iio: adc: Add excitation current sources properties

[Kurt Borja]

On Fri Jun 19, 2026 at 9:27 AM -05, David Lechner wrote:
> On 6/18/26 7:33 PM, Kurt Borja wrote:
>> Some ADCs incorporate current sources that provide excitation current to
>> resistive temperature devices (RTDs), thermistors diodes and other
>> resistive sensors that require constant current biasing.
>> 
>> The maxItems constraint of 16 is arbitrary but should be big enough for
>> most devices.
>
> I wouldn't put an arbitrary limit here. The bindings that include it
> can extend it to add a limit that makes sense instead.

I agree.

This was partly a misunderstanding. I thought -microamp properties fall
back to uint32 not uint32-array but it's the other way around right?

>
>> 
>> Signed-off-by: Kurt Borja <kuurtb@xxxxxxxxx>
>> ---
>>  Documentation/devicetree/bindings/iio/adc/adc.yaml | 23 ++++++++++++++++++++++
>>  1 file changed, 23 insertions(+)
>> 
>> diff --git a/Documentation/devicetree/bindings/iio/adc/adc.yaml b/Documentation/devicetree/bindings/iio/adc/adc.yaml
>> index c74c2084fdb68c..106b1e317411d5 100644
>> --- a/Documentation/devicetree/bindings/iio/adc/adc.yaml
>> +++ b/Documentation/devicetree/bindings/iio/adc/adc.yaml
>> @@ -83,6 +83,29 @@ properties:
>>        This array describes either a single reference source or a positive and
>>        negative reference sources.
>>  
>> +  excitation-channels:
>> +    $ref: /schemas/types.yaml#/definitions/uint32-array
>> +    maxItems: 16
>> +    minItems: 1
>> +    description:
>> +      Excitation current sources provide current to resistive temperature
>> +      devices (RTDs), thermistors diodes and other resistive sensors that
>> +      require constant current biasing.
>> +
>> +      This array describes the mux configuration of the excitation current
>> +      sources.
>> +
>> +  excitation-current-microamp:
>> +    maxItems: 16
>> +    minItems: 1
>> +    description:
>> +      Excitation current sources provide current to resistive temperature
>> +      devices (RTDs), thermistors diodes and other resistive sensors that
>> +      require constant current biasing.
>> +
>> +      This array describes the current configuration of the excitation current
>> +      sources or the single matched current for all sources.
>> +
>>  anyOf:
>>    - oneOf:
>>        - required:
>> 

-- 
Thanks,
 ~ Kurt