xref: /linux/Documentation/devicetree/bindings/iio/adc/ti,ads112c14.yaml (revision 93e4b3076b5f2d853462b9777d083c77fc0b7b23)

# SPDX-License-Identifier: (GPL-2.0-only OR BSD-2-Clause)
%YAML 1.2
---
$id: http://devicetree.org/schemas/iio/adc/ti,ads112c14.yaml#
$schema: http://devicetree.org/meta-schemas/core.yaml#

title: Texas Instruments' ADS112C14 and similar ADC chips

description: |
  Supports the following Texas Instruments' ADC chips:
  - ADS112C14 (16-bit)
  - ADS122C14 (24-bit)

  https://www.ti.com/lit/ds/symlink/ads122c14.pdf

  These chips are primarily designed for use with resistive sensors such as
  RTDs, thermocouples, Wheatstone bridges, etc. The channel bindings reflect
  this in that each channel represents the conditions required to make a
  measurement rather than strictly just the physical input channels.

maintainers:
  - David Lechner <dlechner@baylibre.com>

properties:
  compatible:
    enum:
      - ti,ads112c14
      - ti,ads122c14

  reg:
    items:
      - minimum: 0x40
        maximum: 0x47

  clocks:
    maxItems: 1
    description: Optional external clock connected to GPIO3 pin.

  avdd-supply: true
  dvdd-supply: true

  refp-supply: true
  refn-supply: true

  ti,refp-refn-resistor-ohms:
    description:
      The resistance of the external resistor between REFP and REFN when using
      resistor bridge driven by current outputs for RTD measurements.

  interrupts:
    minItems: 1
    items:
      - description: /FAULT interrupt (GPIO2 pin)
      - description: /DRDY interrupt (GPIO3 pin)

  interrupt-names:
    minItems: 1
    maxItems: 2
    items:
      enum: [fault, drdy]

  gpio-controller: true
  '#gpio-cells':
    const: 2

  '#address-cells':
    const: 1

  '#size-cells':
    const: 0

patternProperties:
  ^channel@[0-9a-f]$:
    $ref: adc.yaml

    unevaluatedProperties: false

    properties:
      reg:
        items:
          - maximum: 15 # arbitrary limit, channel@ can be any combination of AIN0-AIN7

      single-channel:
        maximum: 7

      diff-channels:
        items:
          maximum: 7

      bipolar: true

      input-chopping: true

      excitation-channels:
        maxItems: 2
        items:
          maximum: 7

      excitation-current-nanoamp:
        maxItems: 2
        items:
          enum: [1000, 10000, 20000, 30000, 40000, 50000, 60000, 70000, 80000,
                 90000, 100000, 200000, 300000, 400000, 500000, 600000, 700000,
                 800000, 900000, 1000000]

      burn-out-current-nanoamp:
        items:
          - enum: [200, 1000, 10000]

      reference-sources:
        items:
          - enum: [internal-2.5v, internal-1.25v, external, avdd]
            default: internal-2.5v

    dependencies:
      excitation-channels: [ excitation-current-nanoamp ]
      excitation-current-nanoamp: [ excitation-channels ]

    oneOf:
      - required: [ single-channel ]
      - required: [ diff-channels ]

unevaluatedProperties: false

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

# /DRDY out and CLK in use the same AIN7/GPIO3 pin.
if:
  required:
    - interrupt-names
  properties:
    interrupt-names:
      contains:
        const: drdy
then:
  properties:
    clocks: false

examples:
  - |
    i2c {
        #address-cells = <1>;
        #size-cells = <0>;

        adc@40 {
            compatible = "ti,ads112c14";
            reg = <0x40>;

            avdd-supply = <&avdd>;
            dvdd-supply = <&dvdd>;

            /* 3-Wire RTD: Two IDACs, One Measurement (AIN1-AIN2) */

            ti,refp-refn-resistor-ohms = <500>;

            #address-cells = <1>;
            #size-cells = <0>;

            channel@0 {
                reg = <0>;
                diff-channels = <1>, <2>;
                input-chopping;
                excitation-channels = <0>, <3>;
                excitation-current-nanoamp = <500000>, <500000>;
                reference-sources = "external";
                label = "rtd";
            };
        };
    };
  - |
    i2c {
        #address-cells = <1>;
        #size-cells = <0>;

        adc@40 {
            compatible = "ti,ads112c14";
            reg = <0x40>;

            avdd-supply = <&avdd>;
            dvdd-supply = <&dvdd>;

            /* Resistive Bridge Measurement With a Thermistor for Temperature Compensation */

            refp-supply = <&avdd>;

            #address-cells = <1>;
            #size-cells = <0>;

            channel@0 {
                reg = <0>;
                diff-channels = <6>, <7>;
                bipolar;
                reference-sources = "external";
                label = "bridge";
            };

            channel@1 {
                reg = <1>;
                diff-channels = <1>, <2>;
                reference-sources = "internal-2.5v";
                label = "thermistor";
            };
        };
    };