Documentation/devicetree/bindings/iio/resolver/adi,ad2s1210.yaml

# SPDX-License-Identifier: (GPL-2.0-only OR BSD-2-Clause)
%YAML 1.2
---
$id: http://devicetree.org/schemas/iio/resolver/adi,ad2s1210.yaml#
$schema: http://devicetree.org/meta-schemas/core.yaml#

title: Analog Devices AD2S1210 Resolver-to-Digital Converter

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

description: |
  The AD2S1210 is a complete 10-bit to 16-bit resolution tracking
  resolver-to-digital converter, integrating an on-board programmable
  sinusoidal oscillator that provides sine wave excitation for
  resolvers.

  The AD2S1210 allows the user to read the angular position or the
  angular velocity data directly from the parallel outputs or through
  the serial interface.

  The mode of operation of the communication channel (parallel or serial) is
  selected by the A0 and A1 input pins. In normal mode, data is latched by
  toggling the SAMPLE line and can then be read directly. In configuration mode,
  data is read or written using a register access scheme (address byte with
  read/write flag and data byte).

    A1  A0  Result
     0   0  Normal mode - position output
     0   1  Normal mode - velocity output
     1   0  Reserved
     1   1  Configuration mode

  In normal mode, the resolution of the digital output is selected using
  the RES0 and RES1 input pins. In configuration mode, the resolution is
  selected by setting the RES0 and RES1 bits in the control register.

  RES1  RES0  Resolution (Bits)
     0     0  10
     0     1  12
     1     0  14
     1     1  16

  Note on SPI connections: The CS line on the AD2S1210 should hard-wired to
  logic low and the WR/FSYNC line on the AD2S1210 should be connected to the
  SPI CSn output of the SPI controller.

  Datasheet:
  https://www.analog.com/media/en/technical-documentation/data-sheets/ad2s1210.pdf

properties:
  compatible:
    const: adi,ad2s1210

  reg:
    maxItems: 1

  spi-max-frequency:
    maximum: 25000000

  spi-cpha: true

  avdd-supply:
    description:
      A 4.75 to 5.25 V regulator that powers the Analog Supply Voltage (AVDD)
      pin.

  dvdd-supply:
    description:
      A 4.75 to 5.25 V regulator that powers the Digital Supply Voltage (DVDD)
      pin.

  vdrive-supply:
    description:
      A 2.3 to 5.25 V regulator that powers the Logic Power Supply Input
      (VDrive) pin.

  clocks:
    maxItems: 1
    description: External oscillator clock (CLKIN).

  reset-gpios:
    description:
      GPIO connected to the /RESET pin. As the line needs to be low for the
      reset to be active, it should be configured as GPIO_ACTIVE_LOW.
    maxItems: 1

  sample-gpios:
    description:
      GPIO connected to the /SAMPLE pin. As the line needs to be low to trigger
      a sample, it should be configured as GPIO_ACTIVE_LOW.
    maxItems: 1

  mode-gpios:
    description:
      GPIO lines connected to the A0 and A1 pins. These pins select the data
      transfer mode.
    minItems: 2
    maxItems: 2

  resolution-gpios:
    description:
      GPIO lines connected to the RES0 and RES1 pins. These pins select the
      resolution of the digital output. If omitted, it is assumed that the
      RES0 and RES1 pins are hard-wired to match the assigned-resolution-bits
      property.
    minItems: 2
    maxItems: 2

  fault-gpios:
    description:
      GPIO lines connected to the LOT and DOS pins. These pins combined indicate
      the type of fault present, if any. As these pins a pulled low to indicate
      a fault condition, they should be configured as GPIO_ACTIVE_LOW.
    minItems: 2
    maxItems: 2

  adi,fixed-mode:
    description:
      This is used to indicate the selected mode if A0 and A1 are hard-wired
      instead of connected to GPIOS (i.e. mode-gpios is omitted).
    $ref: /schemas/types.yaml#/definitions/string
    enum: [config, velocity, position]

  assigned-resolution-bits:
    description:
      Resolution of the digital output required by the application. This
      determines the precision of the angle and/or the maximum speed that can
      be measured. If resolution-gpios is omitted, it is assumed that RES0 and
      RES1 are hard-wired to match this value.
    enum: [10, 12, 14, 16]

required:
  - compatible
  - reg
  - spi-cpha
  - avdd-supply
  - dvdd-supply
  - vdrive-supply
  - clocks
  - sample-gpios
  - assigned-resolution-bits

oneOf:
  - required:
      - mode-gpios
  - required:
      - adi,fixed-mode

allOf:
  - $ref: /schemas/spi/spi-peripheral-props.yaml#

unevaluatedProperties: false

examples:
  - |
    #include <dt-bindings/gpio/gpio.h>

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

        resolver@0 {
            compatible = "adi,ad2s1210";
            reg = <0>;
            spi-max-frequency = <20000000>;
            spi-cpha;
            avdd-supply = <&avdd_regulator>;
            dvdd-supply = <&dvdd_regulator>;
            vdrive-supply = <&vdrive_regulator>;
            clocks = <&ext_osc>;
            sample-gpios = <&gpio0 90 GPIO_ACTIVE_LOW>;
            mode-gpios = <&gpio0 86 0>, <&gpio0 87 0>;
            resolution-gpios = <&gpio0 88 0>, <&gpio0 89 0>;
            assigned-resolution-bits = <16>;
        };
    };