Re: [PATCH v3 1/2] dt-bindings: iio: adc: ti,ads112c04: Add binding for ADS112C04

[David Lechner <dlechner@baylibre.com>]

On 8/5/26 12:38 AM, 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@gmail.com>
> ---
>  .../devicetree/bindings/iio/adc/ti,ads112c04.yaml  | 146 +++++++++++++++++++++
>  1 file changed, 146 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..ff079bb5b3dd
> --- /dev/null
> +++ b/Documentation/devicetree/bindings/iio/adc/ti,ads112c04.yaml
> @@ -0,0 +1,146 @@
> +# 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@gmail.com>
> +
> +description:
> +  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:
> +    description: Resistance of the external resistor between REFP and REFN.
> +
> +patternProperties:
> +  "^channel@[0-9a-b]$":
> +    $ref: adc.yaml
> +    unevaluatedProperties: false
> +    properties:
> +      reg:
> +        items:
> +          - maximum: 11
> +
> +      single-channel:
> +        maximum: 3
> +
> +      diff-channels:
> +        items:
> +          maximum: 3
> +
> +      excitation-channels:
> +        maxItems: 2
> +        items:
> +          maximum: 3

I{1,2}MUX can also be routed to the REFP and REFN pins, so we need to
go up to 5 here and add a description that explains the mapping.

> +
> +      excitation-current-nanoamp:
> +        maxItems: 2
> +        items:
> +          enum: [10000, 50000, 100000, 250000, 500000, 1000000, 1500000]
> +

The current outputs are not independently configurable on this one
so maxItems: 1 would be fine on this one.

Or I think this works too:

      excitation-current-nanoamp:
        items:
          - enum: [10000, 50000, 100000, 250000, 500000, 1000000, 1500000]


> +      burn-out-current-nanoamp:
> +        items:
> +          - enum: [10000]

When there is only one possibility:

             - const: 10000

> +
> +      reference-sources:
> +        items:
> +          - enum: [internal-2.048v, external, avdd]
> +            default: internal-2.048v

Since there is only one internal, we can just call it "internal".

> +
> +    dependencies:
> +      excitation-channels: [ excitation-current-nanoamp ]
> +      excitation-current-nanoamp: [ excitation-channels ]
> +
> +    oneOf:
> +      - required: [ single-channel ]
> +      - required: [ diff-channels ]
> +
> +required:
> +  - compatible
> +  - reg
> +  - avdd-supply
> +  - dvdd-supply
> +
> +dependencies:
> +  refn-supply: [ refp-supply ]
> +
> +oneOf:
> +  - required:
> +      - refp-supply
> +  - required:
> +      - ti,refp-refn-resistor-ohms
> +  - properties:
> +      refp-supply: false
> +      refn-supply: false
> +      ti,refp-refn-resistor-ohms: false
> +
> +unevaluatedProperties: false
> +
> +examples:
> +  - |
> +    #include <dt-bindings/interrupt-controller/irq.h>
> +    #include <dt-bindings/gpio/gpio.h>
> +    i2c {
> +        #address-cells = <1>;
> +        #size-cells = <0>;
> +
> +        adc@40 {
> +            compatible = "ti,ads112c04";
> +            reg = <0x40>;
> +            interrupt-parent = <&gpio>;
> +            interrupts = <12 IRQ_TYPE_EDGE_FALLING>;
> +
> +            reset-gpios = <&gpio 13 GPIO_ACTIVE_LOW>;
> +            avdd-supply = <&vdd_3v3_reg>;
> +            dvdd-supply = <&vdd_3v3_reg>;
> +            refp-supply = <&vref_reg>;
> +
> +            #address-cells = <1>;
> +            #size-cells = <0>;
> +
> +            channel@0 {
> +                reg = <0>;
> +                diff-channels = <0>, <1>;
> +            };
> +
> +            channel@1 {
> +                reg = <1>;
> +                single-channel = <2>;
> +            };
> +        };
> +    };
>