Re: [PATCH v2 1/2] dt-bindings: iio: adc: ti,ads112c04: Add binding for ADS112C04

[Kyle Hsieh]

On Fri, Jul 31, 2026 at 9:52 PM David Lechner <dlechner@xxxxxxxxxxxx> wrote:
>
> On 7/30/26 9:58 PM, Kyle Hsieh wrote:
> > Add device tree binding documentation for Texas Instruments ADS112C04
> > I2C Analog-to-Digital Converters.
> >
> > These devices provide 4-channel, 16-bit delta-sigma ADCs with an I2C
> > interface, programmable gain amplifier (PGA), and data-ready (DRDY)
> > interrupt output.
> >
> > The binding uses child nodes to dynamically define the connected
> > single-ended or differential channels.
> >
> > Signed-off-by: Kyle Hsieh <kylehsieh1995@xxxxxxxxx>
> > ---
> >  .../devicetree/bindings/iio/adc/ti,ads112c04.yaml  | 122 +++++++++++++++++++++
> >  1 file changed, 122 insertions(+)
> >
> > diff --git a/Documentation/devicetree/bindings/iio/adc/ti,ads112c04.yaml b/Documentation/devicetree/bindings/iio/adc/ti,ads112c04.yaml
> > new file mode 100644
> > index 000000000000..6a5ffda84b80
> > --- /dev/null
> > +++ b/Documentation/devicetree/bindings/iio/adc/ti,ads112c04.yaml
> > @@ -0,0 +1,122 @@
> > +# SPDX-License-Identifier: (GPL-2.0-only OR BSD-2-Clause)
> > +%YAML 1.2
> > +---
> > +$id: http://devicetree.org/schemas/iio/adc/ti,ads112c04.yaml#
> > +$schema: http://devicetree.org/meta-schemas/core.yaml#
> > +
> > +title: Texas Instruments ADS112C04 ADC
> > +
> > +maintainers:
> > +  - Kyle Hsieh <kylehsieh1995@xxxxxxxxx>
> > +
> > +description: |
>
> The | isn't needed in this case. (It is only needed if we needed
> to preserve formatting, or if there is a : in the text that would
> be interpreted as a dict key.)
Understood. I will remove the `|` from in v3.
>
> > +  The ADS112C04 (16-bit) are precision analog-to-digital converters (ADCs)
> > +  with an I2C interface. They feature a flexible input multiplexer, a
> > +  low-noise programmable gain amplifier (PGA), two programmable excitation
> > +  current sources, a voltage reference, and a precision temperature sensor.
> > +
> > +properties:
> > +  compatible:
> > +    enum:
> > +      - ti,ads112c04
> > +
> > +  reg:
> > +    maxItems: 1
> > +    description: I2C address of the device.
> > +
> > +  interrupts:
> > +    maxItems: 1
> > +    description: Data ready (DRDY) interrupt output.
> > +
> > +  "#address-cells":
> > +    const: 1
> > +
> > +  "#size-cells":
> > +    const: 0
> > +
> > +  reset-gpios:
> > +    maxItems: 1
> > +    description: GPIO connected to the RESET pin. Active low.
> > +
> > +  avdd-supply: true
> > +  dvdd-supply: true
> > +
> > +  refp-supply: true
> > +  refn-supply: true
> > +
> > +  ti,refp-refn-resistor-ohms:
> > +    $ref: /schemas/types.yaml#/definitions/uint32
>
> As the bot said, don't need $ref here because it is a standard unit.
> (So don't forget to run `make dt_binding_check DT_SCHEMA_FILES=ads112c04`
> before sending.)
Yes, the `dt_binding_check` robot caught this right away. I will
removed the redundant `$ref` and resolved the warning locally.
>
> > +    description: Resistance of the external resistor between REFP and REFN.
> > +
> > +patternProperties:
> > +  "^channel@[0-9a-f]$":
> > +    $ref: adc.yaml
> > +    unevaluatedProperties: false
> > +    properties:
> > +      reg:
> > +        items:
> > +          - maximum: 15
>
> This chip doesn't allow arbitrary combinations, so there
> are actually only 12 possible single-channel + diff-channels
> values. So maximum: 11 and channel@[0-9a-b] would make sense.
I will update the regex and set the reg maximum to 11 to strictly reflect
the 12 possible MUX configurations supported by the hardware.
>
> > +
> > +      single-channel:
> > +        maximum: 3
> > +
> > +      diff-channels:
> > +        items:
> > +          maximum: 3
>
> For this chip, we should also have excitation-channels, excitation-current-nanoamp,
> and reference-sources.
I will add these properties to the binding to fully describe
the hardware capabilities.
>
> > +
> > +    oneOf:
> > +      - required: [ single-channel ]
> > +      - required: [ diff-channels ]
> > +