dt-bindings: clock: Add Apple NCO

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

%YAML 1.2

---

$id: http://devicetree.org/schemas/clock/apple,nco.yaml#

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

title: Apple SoCs' NCO block

maintainers:

  - Martin Povišer <povik+lin@cutebit.org>

description: |

  The NCO (Numerically Controlled Oscillator) block found on Apple SoCs

  such as the t8103 (M1) is a programmable clock generator performing

  fractional division of a high frequency input clock.

  It carries a number of independent channels and is typically used for

  generation of audio bitclocks.

properties:

  compatible:

    items:

      - enum:

          - apple,t6000-nco

          - apple,t8103-nco

      - const: apple,nco

  clocks:

    description:

      Specifies the reference clock from which the output clocks

      are derived through fractional division.

    maxItems: 1

  '#clock-cells':

    const: 1

  reg:

    maxItems: 1

required:

  - compatible

  - clocks

  - '#clock-cells'

  - reg

additionalProperties: false

examples:

  - |

    nco_clkref: clock-ref {

      compatible = "fixed-clock";

      #clock-cells = <0>;

      clock-frequency = <900000000>;

      clock-output-names = "nco-ref";

    };

    nco: clock-controller@23b044000 {

      compatible = "apple,t8103-nco", "apple,nco";

      reg = <0x3b044000 0x14000>;

      #clock-cells = <1>;

      clocks = <&nco_clkref>;

    };