dt-bindings: serial: meson-uart: convert to yaml

Amlogic Meson SoC UART Serial Interface

=======================================

The Amlogic Meson SoC UART Serial Interface is present on a large range

of SoCs, and can be present either in the "Always-On" power domain or the

"Everything-Else" power domain.

The particularity of the "Always-On" Serial Interface is that the hardware

is active since power-on and does not need any clock gating and is usable

as very early serial console.

Required properties:

- compatible : compatible: value should be different for each SoC family as :

	- Meson6 : "amlogic,meson6-uart"

	- Meson8 : "amlogic,meson8-uart"

	- Meson8b : "amlogic,meson8b-uart"

	- GX (GXBB, GXL, GXM) : "amlogic,meson-gx-uart"

	eventually followed by : "amlogic,meson-ao-uart" if this UART interface

	is in the "Always-On" power domain.

- reg : offset and length of the register set for the device.

- interrupts : identifier to the device interrupt

- clocks : a list of phandle + clock-specifier pairs, one for each

	   entry in clock names.

- clock-names :

   * "xtal" for external xtal clock identifier

   * "pclk" for the bus core clock, either the clk81 clock or the gate clock

   * "baud" for the source of the baudrate generator, can be either the xtal

	or the pclk.

e.g.

uart_A: serial@84c0 {

	compatible = "amlogic,meson-gx-uart";

	reg = <0x0 0x84c0 0x0 0x14>;

	interrupts = <GIC_SPI 26 IRQ_TYPE_EDGE_RISING>;

	/* Use xtal as baud rate clock source */

	clocks = <&xtal>, <&clkc CLKID_UART0>, <&xtal>;

	clock-names = "xtal", "pclk", "baud";

};

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

# Copyright 2019 BayLibre, SAS

%YAML 1.2

---

$id: "http://devicetree.org/schemas/serial/amlogic,meson-uart.yaml#"

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

title: Amlogic Meson SoC UART Serial Interface

maintainers:

  - Neil Armstrong <narmstrong@baylibre.com>

description: |

  The Amlogic Meson SoC UART Serial Interface is present on a large range

  of SoCs, and can be present either in the "Always-On" power domain or the

  "Everything-Else" power domain.

  The particularity of the "Always-On" Serial Interface is that the hardware

  is active since power-on and does not need any clock gating and is usable

  as very early serial console.

properties:

  compatible:

    oneOf:

      - description: Always-on power domain UART controller

        items:

        - enum:

          - amlogic,meson6-uart

          - amlogic,meson8-uart

          - amlogic,meson8b-uart

          - amlogic,meson-gx-uart

        - const: amlogic,meson-ao-uart

      - description: Everything-Else power domain UART controller

        enum:

        - amlogic,meson6-uart

        - amlogic,meson8-uart

        - amlogic,meson8b-uart

        - amlogic,meson-gx-uart

  reg:

    maxItems: 1

  interrupts:

    maxItems: 1

  clocks:

    items:

      - description: external xtal clock identifier

      - description: the bus core clock, either the clk81 clock or the gate clock

      - description: the source of the baudrate generator, can be either the xtal or the pclk

  clock-names:

    items:

      - const: xtal

      - const: pclk

      - const: baud

required:

  - compatible

  - reg

  - interrupts

  - clocks

  - clock-names

examples:

  - |

    serial@84c0 {

          compatible = "amlogic,meson-gx-uart";

          reg = <0x84c0 0x14>;

          interrupts = <26>;

          clocks = <&xtal>, <&pclk>, <&xtal>;

          clock-names = "xtal", "pclk", "baud";

    };