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

[Kurt Borja]

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@xxxxxxxxxxxx>
> ---
>  .../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?

Also, do you think excitation-pins might be a better name?

> +        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 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.

> +        $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