dt-bindings: mailbox : arm,mhu: Convert to Json-schema

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

%YAML 1.2

---

$id: http://devicetree.org/schemas/mailbox/arm,mhu.yaml#

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

title: ARM MHU Mailbox Controller

maintainers:

  - Jassi Brar <jaswinder.singh@linaro.org>

description: |

  The ARM's Message-Handling-Unit (MHU) is a mailbox controller that has 3

  independent channels/links to communicate with remote processor(s).  MHU links

  are hardwired on a platform. A link raises interrupt for any received data.

  However, there is no specified way of knowing if the sent data has been read

  by the remote. This driver assumes the sender polls STAT register and the

  remote clears it after having read the data.  The last channel is specified to

  be a 'Secure' resource, hence can't be used by Linux running NS.

# We need a select here so we don't match all nodes with 'arm,primecell'

select:

  properties:

    compatible:

      contains:

        const: arm,mhu

  required:

    - compatible

properties:

  compatible:

    items:

      - const: arm,mhu

      - const: arm,primecell

  reg:

    maxItems: 1

  interrupts:

    items:

      - description: low-priority non-secure

      - description: high-priority non-secure

      - description: Secure

    maxItems: 3

  clocks:

    maxItems: 1

  clock-names:

    items:

      - const: apb_pclk

  '#mbox-cells':

    description: Index of the channel.

    const: 1

required:

  - compatible

  - reg

  - interrupts

  - '#mbox-cells'

additionalProperties: false

examples:

  - |

    soc {

        #address-cells = <2>;

        #size-cells = <2>;

        mhuA: mailbox@2b1f0000 {

            #mbox-cells = <1>;

            compatible = "arm,mhu", "arm,primecell";

            reg = <0 0x2b1f0000 0 0x1000>;

            interrupts = <0 36 4>, /* LP-NonSecure */

                         <0 35 4>, /* HP-NonSecure */

                         <0 37 4>; /* Secure */

            clocks = <&clock 0 2 1>;

            clock-names = "apb_pclk";

        };

        mhu_client_scb: scb@2e000000 {

            compatible = "fujitsu,mb86s70-scb-1.0";

            reg = <0 0x2e000000 0 0x4000>;

            mboxes = <&mhuA 1>; /* HP-NonSecure */

        };

    };

ARM MHU Mailbox Driver

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

The ARM's Message-Handling-Unit (MHU) is a mailbox controller that has

3 independent channels/links to communicate with remote processor(s).

 MHU links are hardwired on a platform. A link raises interrupt for any

received data. However, there is no specified way of knowing if the sent

data has been read by the remote. This driver assumes the sender polls

STAT register and the remote clears it after having read the data.

The last channel is specified to be a 'Secure' resource, hence can't be

used by Linux running NS.

Mailbox Device Node:

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

Required properties:

--------------------

- compatible:		Shall be "arm,mhu" & "arm,primecell"

- reg:			Contains the mailbox register address range (base

			address and length)

- #mbox-cells		Shall be 1 - the index of the channel needed.

- interrupts:		Contains the interrupt information corresponding to

			each of the 3 links of MHU.

Example:

--------

	mhu: mailbox@2b1f0000 {

		#mbox-cells = <1>;

		compatible = "arm,mhu", "arm,primecell";

		reg = <0 0x2b1f0000 0x1000>;

		interrupts = <0 36 4>, /* LP-NonSecure */

			     <0 35 4>, /* HP-NonSecure */

			     <0 37 4>; /* Secure */

		clocks = <&clock 0 2 1>;

		clock-names = "apb_pclk";

	};

	mhu_client: scb@2e000000 {

		compatible = "fujitsu,mb86s70-scb-1.0";

		reg = <0 0x2e000000 0x4000>;

		mboxes = <&mhu 1>; /* HP-NonSecure */

	};