path: root/Documentation/devicetree/bindings/iio/adc/st,stm32-adc.yaml

# SPDX-License-Identifier: (GPL-2.0 OR BSD-2-Clause)
%YAML 1.2
---
$id: "http://devicetree.org/schemas/bindings/iio/adc/st,stm32-adc.yaml#"
$schema: "http://devicetree.org/meta-schemas/core.yaml#"

title: STMicroelectronics STM32 ADC bindings

description: |
  STM32 ADC is a successive approximation analog-to-digital converter.
  It has several multiplexed input channels. Conversions can be performed
  in single, continuous, scan or discontinuous mode. Result of the ADC is
  stored in a left-aligned or right-aligned 32-bit data register.
  Conversions can be launched in software or using hardware triggers.

  The analog watchdog feature allows the application to detect if the input
  voltage goes beyond the user-defined, higher or lower thresholds.

  Each STM32 ADC block can have up to 3 ADC instances.

maintainers:
  - Fabrice Gasnier <fabrice.gasnier@st.com>

properties:
  compatible:
    enum:
      - st,stm32f4-adc-core
      - st,stm32h7-adc-core
      - st,stm32mp1-adc-core

  reg:
    maxItems: 1

  interrupts:
    description: |
      One or more interrupts for ADC block, depending on part used:
        - stm32f4 and stm32h7 share a common ADC interrupt line.
        - stm32mp1 has two separate interrupt lines, one for each ADC within
          ADC block.
    minItems: 1
    maxItems: 2

  clocks:
    description: |
      Core can use up to two clocks, depending on part used:
        - "adc" clock: for the analog circuitry, common to all ADCs.
          It's required on stm32f4.
          It's optional on stm32h7 and stm32mp1.
        - "bus" clock: for registers access, common to all ADCs.
          It's not present on stm32f4.
          It's required on stm32h7 and stm32mp1.

  clock-names: true

  st,max-clk-rate-hz:
    description:
      Allow to specify desired max clock rate used by analog circuitry.

  vdda-supply:
    description: Phandle to the vdda input analog voltage.

  vref-supply:
    description: Phandle to the vref input analog reference voltage.

  booster-supply:
    description:
      Phandle to the embedded booster regulator that can be used to supply ADC
      analog input switches on stm32h7 and stm32mp1.

  vdd-supply:
    description:
      Phandle to the vdd input voltage. It can be used to supply ADC analog
      input switches on stm32mp1.

  st,syscfg:
    description:
      Phandle to system configuration controller. It can be used to control the
      analog circuitry on stm32mp1.
    allOf:
      - $ref: "/schemas/types.yaml#/definitions/phandle-array"

  interrupt-controller: true

  '#interrupt-cells':
    const: 1

  '#address-cells':
    const: 1

  '#size-cells':
    const: 0

allOf:
  - if:
      properties:
        compatible:
          contains:
            const: st,stm32f4-adc-core

    then:
      properties:
        clocks:
          maxItems: 1

        clock-names:
          const: adc

        interrupts:
          items:
            - description: interrupt line common for all ADCs

        st,max-clk-rate-hz:
          minimum: 600000
          maximum: 36000000
          default: 36000000

        booster-supply: false

        vdd-supply: false

        st,syscfg: false

  - if:
      properties:
        compatible:
          contains:
            const: st,stm32h7-adc-core

    then:
      properties:
        clocks:
          minItems: 1
          maxItems: 2

        clock-names:
          items:
            - const: bus
            - const: adc
          minItems: 1
          maxItems: 2

        interrupts:
          items:
            - description: interrupt line common for all ADCs

        st,max-clk-rate-hz:
          minimum: 120000
          maximum: 36000000
          default: 36000000

        vdd-supply: false

        st,syscfg: false

  - if:
      properties:
        compatible:
          contains:
            const: st,stm32mp1-adc-core

    then:
      properties:
        clocks:
          minItems: 1
          maxItems: 2

        clock-names:
          items:
            - const: bus
            - const: adc
          minItems: 1
          maxItems: 2

        interrupts:
          items:
            - description: interrupt line for ADC1
            - description: interrupt line for ADC2

        st,max-clk-rate-hz:
          minimum: 120000
          maximum: 36000000
          default: 36000000

additionalProperties: false

required:
  - compatible
  - reg
  - interrupts
  - clocks
  - clock-names
  - vdda-supply
  - vref-supply
  - interrupt-controller
  - '#interrupt-cells'
  - '#address-cells'
  - '#size-cells'

patternProperties:
  "^adc@[0-9]+$":
    type: object
    description:
      An ADC block node should contain at least one subnode, representing an
      ADC instance available on the machine.

    properties:
      compatible:
        enum:
          - st,stm32f4-adc
          - st,stm32h7-adc
          - st,stm32mp1-adc

      reg:
        description: |
          Offset of ADC instance in ADC block. Valid values are:
            - 0x0:   ADC1
            - 0x100: ADC2
            - 0x200: ADC3 (stm32f4 only)
        maxItems: 1

      '#io-channel-cells':
        const: 1

      interrupts:
        description: |
          IRQ Line for the ADC instance. Valid values are:
            - 0 for adc@0
            - 1 for adc@100
            - 2 for adc@200 (stm32f4 only)
        maxItems: 1

      clocks:
        description:
          Input clock private to this ADC instance. It's required only on
          stm32f4, that has per instance clock input for registers access.
        maxItems: 1

      dmas:
        description: RX DMA Channel
        maxItems: 1

      dma-names:
        const: rx

      assigned-resolution-bits:
        description: |
          Resolution (bits) to use for conversions:
            - can be 6, 8, 10 or 12 on stm32f4
            - can be 8, 10, 12, 14 or 16 on stm32h7 and stm32mp1
        allOf:
          - $ref: /schemas/types.yaml#/definitions/uint32

      st,adc-channels:
        description: |
          List of single-ended channels muxed for this ADC. It can have up to:
            - 16 channels, numbered from 0 to 15 (for in0..in15) on stm32f4
            - 20 channels, numbered from 0 to 19 (for in0..in19) on stm32h7 and
              stm32mp1.
        allOf:
          - $ref: /schemas/types.yaml#/definitions/uint32-array

      st,adc-diff-channels:
        description: |
          List of differential channels muxed for this ADC. Some channels can
          be configured as differential instead of single-ended on stm32h7 and
          on stm32mp1. Positive and negative inputs pairs are listed:
          <vinp vinn>, <vinp vinn>,... vinp and vinn are numbered from 0 to 19.

          Note: At least one of "st,adc-channels" or "st,adc-diff-channels" is
          required. Both properties can be used together. Some channels can be
          used as single-ended and some other ones as differential (mixed). But
          channels can't be configured both as single-ended and differential.
        allOf:
          - $ref: /schemas/types.yaml#/definitions/uint32-matrix
          - items:
              items:
                - description: |
                    "vinp" indicates positive input number
                  minimum: 0
                  maximum: 19
                - description: |
                    "vinn" indicates negative input number
                  minimum: 0
                  maximum: 19

      st,min-sample-time-nsecs:
        description:
          Minimum sampling time in nanoseconds. Depending on hardware (board)
          e.g. high/low analog input source impedance, fine tune of ADC
          sampling time may be recommended. This can be either one value or an
          array that matches "st,adc-channels" and/or "st,adc-diff-channels"
          list, to set sample time resp. for all channels, or independently for
          each channel.
        allOf:
          - $ref: /schemas/types.yaml#/definitions/uint32-array

    allOf:
      - if:
          properties:
            compatible:
              contains:
                const: st,stm32f4-adc

        then:
          properties:
            reg:
              enum:
                - 0x0
                - 0x100
                - 0x200

            interrupts:
              minimum: 0
              maximum: 2

            assigned-resolution-bits:
              enum: [6, 8, 10, 12]
              default: 12

            st,adc-channels:
              minItems: 1
              maxItems: 16
              items:
                minimum: 0
                maximum: 15

            st,adc-diff-channels: false

            st,min-sample-time-nsecs:
              minItems: 1
              maxItems: 16
              items:
                minimum: 80

          required:
            - clocks

      - if:
          properties:
            compatible:
              contains:
                enum:
                  - st,stm32h7-adc
                  - st,stm32mp1-adc

        then:
          properties:
            reg:
              enum:
                - 0x0
                - 0x100

            interrupts:
              minimum: 0
              maximum: 1

            assigned-resolution-bits:
              enum: [8, 10, 12, 14, 16]
              default: 16

            st,adc-channels:
              minItems: 1
              maxItems: 20
              items:
                minimum: 0
                maximum: 19

            st,min-sample-time-nsecs:
              minItems: 1
              maxItems: 20
              items:
                minimum: 40

    additionalProperties: false

    anyOf:
      - required:
          - st,adc-channels
      - required:
          - st,adc-diff-channels

    required:
      - compatible
      - reg
      - interrupts
      - '#io-channel-cells'

examples:
  - |
    // Example 1: with stm32f429, ADC1, single-ended channel 8
      adc123: adc@40012000 {
        compatible = "st,stm32f4-adc-core";
        reg = <0x40012000 0x400>;
        interrupts = <18>;
        clocks = <&rcc 0 168>;
        clock-names = "adc";
        st,max-clk-rate-hz = <36000000>;
        vdda-supply = <&vdda>;
        vref-supply = <&vref>;
        interrupt-controller;
        #interrupt-cells = <1>;
        #address-cells = <1>;
        #size-cells = <0>;
        adc@0 {
          compatible = "st,stm32f4-adc";
          #io-channel-cells = <1>;
          reg = <0x0>;
          clocks = <&rcc 0 168>;
          interrupt-parent = <&adc123>;
          interrupts = <0>;
          st,adc-channels = <8>;
          dmas = <&dma2 0 0 0x400 0x0>;
          dma-names = "rx";
          assigned-resolution-bits = <8>;
        };
        // ...
        // other adc child nodes follow...
      };

  - |
    // Example 2: with stm32mp157c to setup ADC1 with:
    // - channels 0 & 1 as single-ended
    // - channels 2 & 3 as differential (with resp. 6 & 7 negative inputs)
      #include <dt-bindings/interrupt-controller/arm-gic.h>
      #include <dt-bindings/clock/stm32mp1-clks.h>
      adc12: adc@48003000 {
        compatible = "st,stm32mp1-adc-core";
        reg = <0x48003000 0x400>;
        interrupts = <GIC_SPI 18 IRQ_TYPE_LEVEL_HIGH>,
                     <GIC_SPI 90 IRQ_TYPE_LEVEL_HIGH>;
        clocks = <&rcc ADC12>, <&rcc ADC12_K>;
        clock-names = "bus", "adc";
        booster-supply = <&booster>;
        vdd-supply = <&vdd>;
        vdda-supply = <&vdda>;
        vref-supply = <&vref>;
        st,syscfg = <&syscfg>;
        interrupt-controller;
        #interrupt-cells = <1>;
        #address-cells = <1>;
        #size-cells = <0>;
        adc@0 {
          compatible = "st,stm32mp1-adc";
          #io-channel-cells = <1>;
          reg = <0x0>;
          interrupt-parent = <&adc12>;
          interrupts = <0>;
          st,adc-channels = <0 1>;
          st,adc-diff-channels = <2 6>, <3 7>;
          st,min-sample-time-nsecs = <5000>;
          dmas = <&dmamux1 9 0x400 0x05>;
          dma-names = "rx";
        };
        // ...
        // other adc child node follow...
      };

...