dt-bindings: rtc: Convert stm32 rtc bindings to json-schema

STM32 Real Time Clock

Required properties:

- compatible: can be one of the following:

  - "st,stm32-rtc" for devices compatible with stm32(f4/f7).

  - "st,stm32h7-rtc" for devices compatible with stm32h7.

  - "st,stm32mp1-rtc" for devices compatible with stm32mp1.

- reg: address range of rtc register set.

- clocks: can use up to two clocks, depending on part used:

  - "rtc_ck": RTC clock source.

  - "pclk": RTC APB interface clock.

    It is not present on stm32(f4/f7).

    It is required on stm32(h7/mp1).

- clock-names: must be "rtc_ck" and "pclk".

    It is required on stm32(h7/mp1).

- interrupts: rtc alarm interrupt. On stm32mp1, a second interrupt is required

  for rtc alarm wakeup interrupt.

- st,syscfg: phandle/offset/mask triplet. The phandle to pwrcfg used to

  access control register at offset, and change the dbp (Disable Backup

  Protection) bit represented by the mask, mandatory to disable/enable backup

  domain (RTC registers) write protection.

    It is required on stm32(f4/f7/h7).

Optional properties (to override default rtc_ck parent clock on stm32(f4/f7/h7):

- assigned-clocks: reference to the rtc_ck clock entry.

- assigned-clock-parents: phandle of the new parent clock of rtc_ck.

Example:

	rtc: rtc@40002800 {

		compatible = "st,stm32-rtc";

		reg = <0x40002800 0x400>;

		clocks = <&rcc 1 CLK_RTC>;

		assigned-clocks = <&rcc 1 CLK_RTC>;

		assigned-clock-parents = <&rcc 1 CLK_LSE>;

		interrupt-parent = <&exti>;

		interrupts = <17 1>;

		st,syscfg = <&pwrcfg 0x00 0x100>;

	};

	rtc: rtc@58004000 {

		compatible = "st,stm32h7-rtc";

		reg = <0x58004000 0x400>;

		clocks = <&rcc RTCAPB_CK>, <&rcc RTC_CK>;

		clock-names = "pclk", "rtc_ck";

		assigned-clocks = <&rcc RTC_CK>;

		assigned-clock-parents = <&rcc LSE_CK>;

		interrupt-parent = <&exti>;

		interrupts = <17 1>;

		interrupt-names = "alarm";

		st,syscfg = <&pwrcfg 0x00 0x100>;

	};

	rtc: rtc@5c004000 {

		compatible = "st,stm32mp1-rtc";

		reg = <0x5c004000 0x400>;

		clocks = <&rcc RTCAPB>, <&rcc RTC>;

		clock-names = "pclk", "rtc_ck";

		interrupts-extended = <&intc GIC_SPI 3 IRQ_TYPE_NONE>,

				      <&exti 19 1>;

	};

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

%YAML 1.2

---

$id: http://devicetree.org/schemas/rtc/st,stm32-rtc.yaml#

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

title: STMicroelectronics STM32 Real Time Clock Bindings

maintainers:

  - Gabriel Fernandez <gabriel.fernandez@st.com>

properties:

  compatible:

    enum:

      - st,stm32-rtc

      - st,stm32h7-rtc

      - st,stm32mp1-rtc

  reg:

    maxItems: 1

  clocks:

    minItems: 1

    maxItems: 2

  clock-names:

    items:

      - const: pclk

      - const: rtc_ck

  interrupts:

    maxItems: 1

  st,syscfg:

    allOf:

      - $ref: "/schemas/types.yaml#/definitions/phandle-array"

      - items:

          minItems: 3

          maxItems: 3

    description: |

       Phandle/offset/mask triplet. The phandle to pwrcfg used to

       access control register at offset, and change the dbp (Disable Backup

       Protection) bit represented by the mask, mandatory to disable/enable backup

       domain (RTC registers) write protection.

  assigned-clocks:

    description: |

      override default rtc_ck parent clock reference to the rtc_ck clock entry

    maxItems: 1

  assigned-clock-parents:

    description: |

      override default rtc_ck parent clock phandle of the new parent clock of rtc_ck

    maxItems: 1

allOf:

  - if:

      properties:

        compatible:

          contains:

            const: st,stm32-rtc

    then:

      properties:

        clocks:

          minItems: 1

          maxItems: 1

        clock-names: false

      required:

        - st,syscfg

  - if:

      properties:

        compatible:

          contains:

            const: st,stm32h7-rtc

    then:

       properties:

         clocks:

           minItems: 2

           maxItems: 2

       required:

         - clock-names

         - st,syscfg

  - if:

      properties:

        compatible:

          contains:

            const: st,stm32mp1-rtc

    then:

       properties:

         clocks:

           minItems: 2

           maxItems: 2

         assigned-clocks: false

         assigned-clock-parents: false

       required:

         - clock-names

required:

  - compatible

  - reg

  - clocks

  - interrupts

examples:

  - |

    #include <dt-bindings/mfd/stm32f4-rcc.h>

    #include <dt-bindings/clock/stm32fx-clock.h>

    rtc@40002800 {

      compatible = "st,stm32-rtc";

      reg = <0x40002800 0x400>;

      clocks = <&rcc 1 CLK_RTC>;

      assigned-clocks = <&rcc 1 CLK_RTC>;

      assigned-clock-parents = <&rcc 1 CLK_LSE>;

      interrupt-parent = <&exti>;

      interrupts = <17 1>;

      st,syscfg = <&pwrcfg 0x00 0x100>;

    };

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

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

    rtc@5c004000 {

      compatible = "st,stm32mp1-rtc";

      reg = <0x5c004000 0x400>;

      clocks = <&rcc RTCAPB>, <&rcc RTC>;

      clock-names = "pclk", "rtc_ck";

      interrupts = <GIC_SPI 3 IRQ_TYPE_LEVEL_HIGH>;

    };

...