Commit 2cd2b093 authored by Jonathan Cameron's avatar Jonathan Cameron
Browse files

dt-bindings:iio:adc:adi,ad7476: Add missing binding document 



This binding covers class of simple SPI ADCs which only provide
data output - they don't have MOSI pin.

The only real variation between them is over how many supplies they
use and which one is used for the reference.

Michael listed as maintainer for this one as it is his driver and
falls under the catch all MAINTAINERS entry for ADI devices.

Signed-off-by: default avatarJonathan Cameron <Jonathan.Cameron@huawei.com>
Cc: Michael Hennerich <michael.hennerich@analog.com>
Reviewed-by: default avatarRob Herring <robh@kernel.org>
Link: https://lore.kernel.org/r/20210425163154.73209-3-jic23@kernel.org
parent 7bf50a96

Documentation/devicetree/bindings/iio/adc/adi,ad7476.yaml

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# SPDX-License-Identifier: (GPL-2.0 OR BSD-2-Clause)

# Copyright 2019 Analog Devices Inc.

%YAML 1.2

---

$id: http://devicetree.org/schemas/iio/adc/adi,ad7476.yaml#

$schema: http://devicetree.org/meta-schemas/core.yaml#



title: AD7476 and similar simple SPI ADCs from multiple manufacturers.



maintainers:

  - Michael Hennerich <michael.hennerich@analog.com>



description: |

  A lot of simple SPI ADCs have very straight forward interfaces.

  They typically don't provide a MOSI pin, simply reading out data

  on MISO when the clock toggles.



properties:

  compatible:

    enum:

      - adi,ad7091

      - adi,ad7091r

      - adi,ad7273

      - adi,ad7274

      - adi,ad7276

      - adi,ad7277

      - adi,ad7278

      - adi,ad7466

      - adi,ad7467

      - adi,ad7468

      - adi,ad7475

      - adi,ad7476

      - adi,ad7476a

      - adi,ad7477

      - adi,ad7477a

      - adi,ad7478

      - adi,ad7478a

      - adi,ad7495

      - adi,ad7910

      - adi,ad7920

      - adi,ad7940

      - ti,adc081s

      - ti,adc101s

      - ti,adc121s

      - ti,ads7866

      - ti,ads7867

      - ti,ads7868

      - lltc,ltc2314-14



  reg:

    maxItems: 1



  vcc-supply:

    description:

      Main powersupply voltage for the chips, sometimes referred to as VDD on

      datasheets.  If there is no separate vref-supply, then this is needed

      to establish channel scaling.



  vdrive-supply:

    description:

      Some devices have separate supply for their digital control side.



  vref-supply:

    description:

      Some devices have a specific reference voltage supplied on a different pin

      to the other supplies. Needed to be able to establish channel scaling

      unless there is also an internal reference available (e.g. ad7091r)



  spi-max-frequency: true



  adi,conversion-start-gpios:

    description: A GPIO used to trigger the start of a conversion

    maxItems: 1



required:

  - compatible

  - reg



additionalProperties: false



allOf:

  # Devices where reference is vcc

  - if:

      properties:

        compatible:

          contains:

            enum:

              - adi,ad7091

              - adi,ad7276

              - adi,ad7277

              - adi,ad7278

              - adi,ad7466

              - adi,ad7467

              - adi,ad7468

              - adi,ad7940

              - ti,adc081s

              - ti,adc101s

              - ti,adc121s

              - ti,ads7866

              - ti,ads7868

      required:

        - vcc-supply

  # Devices with a vref

  - if:

      properties:

        compatible:

          contains:

            enum:

              - adi,ad7091r

              - adi,ad7273

              - adi,ad7274

              - adi,ad7475

              - lltc,ltc2314-14

    then:

      properties:

        vref-supply: true

    else:

      properties:

        vref-supply: false

  # Devices with a vref where it is not optional

  - if:

      properties:

        compatible:

          contains:

            enum:

              - adi,ad7273

              - adi,ad7274

              - adi,ad7475

              - lltc,ltc2314-14

    then:

      required:

        - vref-supply

  - if:

      properties:

        compatible:

          contains:

            enum:

              - adi,ad7475

              - adi,ad7495

    then:

      properties:

        vdrive-supply: true

    else:

      properties:

        vdrive-supply: false

  - if:

      properties:

        compatible:

          contains:

            enum:

              - adi,ad7091

              - adi,ad7091r

    then:

      properties:

        adi,conversion-start-gpios: true

    else:

      properties:

        adi,conversion-start-gpios: false



examples:

  - |

    spi {

      #address-cells = <1>;

      #size-cells = <0>;



      adc@0 {

        compatible = "adi,ad7091r";

        reg = <0>;

        spi-max-frequency = <5000000>;

        vcc-supply = <&adc_vcc>;

        vref-supply = <&adc_vref>;

      };

    };

...