Re: [PATCH 1/4] dt-bindings: iio: adc: add ti,ads122c14

["Kurt Borja" <kuurtb@gmail.com>]

On Tue Jun 16, 2026 at 10:22 AM -05, David Lechner wrote:
> On 6/15/26 7:26 PM, Kurt Borja wrote:
>> On Mon Jun 15, 2026 at 4:59 PM -05, David Lechner (TI) wrote:
>>> Add new bindings for ti,ads122c14 and similar devices.
>>>
>>> This is an ADC that is primarily intended for use with temperature
>>> sensors. There are a few unusual properties because of this. In
>>> particular, the reference voltage source and current output requirements
>>> can be different for each measurement, so these are included in the
>>> channel bindings.
>>>
>>> The REFP/REFN reference voltage is usually just connected to a resistor
>>> that is being driven by the ADC's current outputs, so there is special
>>> property for this case rather than requiring a regulator to be defined
>>> to represent that.
>>>
>>> ti,vref-source is reused from ti,tlv320adcx140.yaml (otherwise might
>>> have preferred an enum of strings).
>>>
>>> Signed-off-by: David Lechner (TI) <dlechner@baylibre.com>
>>> ---
>>>  .../devicetree/bindings/iio/adc/ti,ads112c14.yaml  | 224 +++++++++++++++++++++
>>>  MAINTAINERS                                        |   7 +
>>>  include/dt-bindings/iio/adc/ti,ads112c14.h         |  11 +
>>>  3 files changed, 242 insertions(+)
>>>
>>> diff --git a/Documentation/devicetree/bindings/iio/adc/ti,ads112c14.yaml b/Documentation/devicetree/bindings/iio/adc/ti,ads112c14.yaml
>>> new file mode 100644
>>> index 000000000000..dc7f37cad772
>>> --- /dev/null
>>> +++ b/Documentation/devicetree/bindings/iio/adc/ti,ads112c14.yaml
>>> @@ -0,0 +1,224 @@
>> 
>> [...]
>> 
>>> +patternProperties:
>>> +  ^channel@[0-7]$:
>>> +    $ref: adc.yaml
>>> +
>>> +    unevaluatedProperties: false
>>> +
>>> +    properties:
>>> +      reg:
>>> +        maximum: 16 # arbitrary limit, channel@ can be any combination of AIN0-AIN7
>>> +
>>> +      single-channel:
>>> +        maximum: 7
>>> +
>>> +      diff-channels:
>>> +        items:
>>> +          maximum: 7
>>> +
>>> +      bipolar:
>>> +        description:
>>> +          Set this flag if the differential input can be negative.
>>> +
>>> +      excitation-channels:
>> 
>> I noticed this doesn't have the "ti," prefix. Is your plan to add this
>> to adc.yaml?
>
> I hadn't really though about it. I guess it could make sense.

I think it would be valuable, given that TI is producing quite a few of
this kind of devices.

>
>> 
>> Also, do you think excitation-pins might be a better name?
>
> I used -channels to match e.g. diff-channels. The same values apply to
> both properties.
>
>> 
>>> +        description: AINx pins used as current output.
>>> +        $ref: /schemas/types.yaml#/definitions/uint32-array
>>> +        minItems: 1
>>> +        maxItems: 2
>>> +        items:
>>> +          maximum: 7
>>> +
>>> +      excitation-current-microamp:
>>> +        description: The current output of the excitation channels in microamps.
>>> +        minimum: 1
>>> +        maximum: 1000
>>> +
>>> +      current-chopping:
>> 
>> If you agree with the above comment, I think this too should be added.
>> In that case, can we call this something like
>> excitation-current-rotation for less ambiguity?
>
> I think excitation-channel-rotation would be fine.

I like it.

>
>> 
>> I say this because my device has an "IDAC rotation mode", but it also has
>> a "Chop Mode" which rotates analog inputs and averages consecutive
>> conversions.
>
> And this one sounds like it could be named input-channel-rotation. Would
> this also need a 2nd set of single-channel or diff-channels to the extra
> inputs?

No, just one set. It rotates the positive and negative inputs.

I'll go with input-channel-rotation then!

>
>> 
>>> +        $ref: /schemas/types.yaml#/definitions/flag
>>> +        description:
>>> +          If provided, the two excitation channels are to be used with current
>>> +          chopping enabled.
>>> +
>>> +      ti,vref-source:
>>> +        description: |
>>> +          Indicates the source for the reference voltage for this channel.
>>> +          0 - Internal 2.5V reference
>>> +          1 - Internal 1.25V reference
>>> +          2 - External reference (REFP-REFN)
>>> +          3 - AVDD as reference
>>> +
>>> +          For convenience, macros for these values are available in
>>> +          dt-bindings/iio/adc/ti,ads112c14.h.
>>> +        $ref: /schemas/types.yaml#/definitions/uint32
>>> +        maximum: 3
>>> +        default: 0
>>> +
>>> +    dependencies:
>>> +      excitation-channels: [ excitation-current-microamp ]
>>> +      excitation-current-microamp: [ excitation-channels ]
>>> +      current-chopping: [ excitation-channels ]
>>> +
>>> +    oneOf:
>>> +      - required: [ single-channel ]
>>> +      - required: [ diff-channels ]
>> 
>> [...]
>> 

-- 
Thanks,
 ~ Kurt