dt-bindings: add device tree binding for Arm CryptoCell trng engine

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

%YAML 1.2

---

$id: http://devicetree.org/schemas/rng/arm-cctrng.yaml#

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

title: Arm TrustZone CryptoCell TRNG engine

maintainers:

  - Hadar Gat <hadar.gat@arm.com>

description: |+

  Arm TrustZone CryptoCell TRNG (True Random Number Generator) engine.

properties:

  compatible:

    enum:

      - arm,cryptocell-713-trng

      - arm,cryptocell-703-trng

  interrupts:

    maxItems: 1

  reg:

    maxItems: 1

  arm,rosc-ratio:

    description:

      Arm TrustZone CryptoCell TRNG engine has 4 ring oscillators.

      Sampling ratio values for these 4 ring oscillators. (from calibration)

    allOf:

      - $ref: /schemas/types.yaml#/definitions/uint32-array

      - items:

          maxItems: 4

  clocks:

    maxItems: 1

required:

  - compatible

  - interrupts

  - reg

  - arm,rosc-ratio

additionalProperties: false

examples:

  - |

    arm_cctrng: rng@60000000 {

        compatible = "arm,cryptocell-713-trng";

        interrupts = <0 29 4>;

        reg = <0x60000000 0x10000>;

        arm,rosc-ratio = <5000 1000 500 0>;

    };