dt-bindings: iio: dac: stm32-dac: convert bindings to json-schema

STMicroelectronics STM32 DAC

The STM32 DAC is a 12-bit voltage output digital-to-analog converter. The DAC

may be configured in 8 or 12-bit mode. It has two output channels, each with

its own converter.

It has built-in noise and triangle waveform generator and supports external

triggers for conversions. The DAC's output buffer allows a high drive output

current.

Contents of a stm32 dac root node:

-----------------------------------

Required properties:

- compatible: Should be one of:

  "st,stm32f4-dac-core"

  "st,stm32h7-dac-core"

- reg: Offset and length of the device's register set.

- clocks: Must contain an entry for pclk (which feeds the peripheral bus

  interface)

- clock-names: Must be "pclk".

- vref-supply: Phandle to the vref+ input analog reference supply.

- #address-cells = <1>;

- #size-cells = <0>;

Optional properties:

- resets: Must contain the phandle to the reset controller.

- A pinctrl state named "default" for each DAC channel may be defined to set

  DAC_OUTx pin in mode of operation for analog output on external pin.

Contents of a stm32 dac child node:

-----------------------------------

DAC core node should contain at least one subnode, representing a

DAC instance/channel available on the machine.

Required properties:

- compatible: Must be "st,stm32-dac".

- reg: Must be either 1 or 2, to define (single) channel in use

- #io-channel-cells = <1>: See the IIO bindings section "IIO consumers" in

  Documentation/devicetree/bindings/iio/iio-bindings.txt

Example:

	dac: dac@40007400 {

		compatible = "st,stm32h7-dac-core";

		reg = <0x40007400 0x400>;

		clocks = <&clk>;

		clock-names = "pclk";

		vref-supply = <&reg_vref>;

		pinctrl-names = "default";

		pinctrl-0 = <&dac_out1 &dac_out2>;

		#address-cells = <1>;

		#size-cells = <0>;

		dac1: dac@1 {

			compatible = "st,stm32-dac";

			#io-channels-cells = <1>;

			reg = <1>;

		};

		dac2: dac@2 {

			compatible = "st,stm32-dac";

			#io-channels-cells = <1>;

			reg = <2>;

		};

	};

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

%YAML 1.2

---

$id: "http://devicetree.org/schemas/iio/dac/st,stm32-dac.yaml#"

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

title: STMicroelectronics STM32 DAC bindings

description: |

  The STM32 DAC is a 12-bit voltage output digital-to-analog converter. The DAC

  may be configured in 8 or 12-bit mode. It has two output channels, each with

  its own converter.

  It has built-in noise and triangle waveform generator and supports external

  triggers for conversions. The DAC's output buffer allows a high drive output

  current.

maintainers:

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

properties:

  compatible:

    enum:

      - st,stm32f4-dac-core

      - st,stm32h7-dac-core

  reg:

    maxItems: 1

  resets:

    maxItems: 1

  clocks:

    maxItems: 1

  clock-names:

    items:

      - const: pclk

  vref-supply:

    description: Phandle to the vref input analog reference voltage.

  '#address-cells':

    const: 1

  '#size-cells':

    const: 0

additionalProperties: false

required:

  - compatible

  - reg

  - clocks

  - clock-names

  - vref-supply

  - '#address-cells'

  - '#size-cells'

patternProperties:

  "^dac@[1-2]+$":

    type: object

    description:

      A DAC block node should contain at least one subnode, representing an

      DAC instance/channel available on the machine.

    properties:

      compatible:

        const: st,stm32-dac

      reg:

        description: Must be either 1 or 2, to define (single) channel in use

        enum: [1, 2]

      '#io-channel-cells':

        const: 1

    additionalProperties: false

    required:

      - compatible

      - reg

      - '#io-channel-cells'

examples:

  - |

    // Example on stm32mp157c

    #include <dt-bindings/clock/stm32mp1-clks.h>

    dac: dac@40017000 {

      compatible = "st,stm32h7-dac-core";

      reg = <0x40017000 0x400>;

      clocks = <&rcc DAC12>;

      clock-names = "pclk";

      vref-supply = <&vref>;

      #address-cells = <1>;

      #size-cells = <0>;

      dac@1 {

        compatible = "st,stm32-dac";

        #io-channel-cells = <1>;

        reg = <1>;

      };

      dac@2 {

        compatible = "st,stm32-dac";

        #io-channel-cells = <1>;

        reg = <2>;

      };

    };

...