dt-bindings: spi: Convert imx lpspi to json-schema

* Freescale Low Power SPI (LPSPI) for i.MX

Required properties:

- compatible :

  - "fsl,imx7ulp-spi" for LPSPI compatible with the one integrated on i.MX7ULP soc

  - "fsl,imx8qxp-spi" for LPSPI compatible with the one integrated on i.MX8QXP soc

- reg : address and length of the lpspi master registers

- interrupt-parent : core interrupt controller

- interrupts : lpspi interrupt

- clocks : lpspi clock specifier. Its number and order need to correspond to the

	   value in clock-names.

- clock-names : Corresponding to per clock and ipg clock in "clocks"

		respectively. In i.MX7ULP, it only has per clk, so use CLK_DUMMY

		to fill the "ipg" blank.

- spi-slave : spi slave mode support. In slave mode, add this attribute without

	      value. In master mode, remove it.

Examples:

lpspi2: lpspi@40290000 {

	compatible = "fsl,imx7ulp-spi";

	reg = <0x40290000 0x10000>;

	interrupt-parent = <&intc>;

	interrupts = <GIC_SPI 28 IRQ_TYPE_LEVEL_HIGH>;

	clocks = <&clks IMX7ULP_CLK_LPSPI2>,

		 <&clks IMX7ULP_CLK_DUMMY>;

	clock-names = "per", "ipg";

	spi-slave;

};

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

%YAML 1.2

---

$id: http://devicetree.org/schemas/spi/spi-fsl-lpspi.yaml#

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

title: Freescale Low Power SPI (LPSPI) for i.MX

maintainers:

  - Anson Huang <Anson.Huang@nxp.com>

allOf:

  - $ref: "/schemas/spi/spi-controller.yaml#"

properties:

  compatible:

    enum:

      - fsl,imx7ulp-spi

      - fsl,imx8qxp-spi

  reg:

    maxItems: 1

  interrupts:

    maxItems: 1

  clocks:

    items:

      - description: SoC SPI per clock

      - description: SoC SPI ipg clock

  clock-names:

    items:

      - const: per

      - const: ipg

required:

  - compatible

  - reg

  - interrupts

  - clocks

  - clock-names

unevaluatedProperties: false

examples:

  - |

    #include <dt-bindings/clock/imx7ulp-clock.h>

    #include <dt-bindings/interrupt-controller/arm-gic.h>

    spi@40290000 {

        compatible = "fsl,imx7ulp-spi";

        reg = <0x40290000 0x10000>;

        interrupt-parent = <&intc>;

        interrupts = <GIC_SPI 28 IRQ_TYPE_LEVEL_HIGH>;

        clocks = <&clks IMX7ULP_CLK_LPSPI2>,

                 <&clks IMX7ULP_CLK_DUMMY>;

        clock-names = "per", "ipg";

        spi-slave;

    };