dt-bindings: fu740: prci: add YAML documentation for the FU740 PRCI

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

# Copyright (C) 2020 SiFive, Inc.

%YAML 1.2

---

$id: http://devicetree.org/schemas/clock/sifive/fu740-prci.yaml#

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

title: SiFive FU740 Power Reset Clock Interrupt Controller (PRCI)

maintainers:

  - Zong Li <zong.li@sifive.com>

  - Paul Walmsley  <paul.walmsley@sifive.com>

description:

  On the FU740 family of SoCs, most system-wide clock and reset integration

  is via the PRCI IP block.

  The clock consumer should specify the desired clock via the clock ID

  macros defined in include/dt-bindings/clock/sifive-fu740-prci.h.

  These macros begin with PRCI_CLK_.

  The hfclk and rtcclk nodes are required, and represent physical

  crystals or resonators located on the PCB.  These nodes should be present

  underneath /, rather than /soc.

properties:

  compatible:

    const: sifive,fu740-c000-prci

  reg:

    maxItems: 1

  clocks:

    items:

      - description: high frequency clock.

      - description: RTL clock.

  clock-names:

    items:

      - const: hfclk

      - const: rtcclk

  "#clock-cells":

    const: 1

required:

  - compatible

  - reg

  - clocks

  - "#clock-cells"

additionalProperties: false

examples:

  - |

    prci: clock-controller@10000000 {

      compatible = "sifive,fu740-c000-prci";

      reg = <0x10000000 0x1000>;

      clocks = <&hfclk>, <&rtcclk>;

      #clock-cells = <1>;

    };