dt-bindings: mailbox: meson-mhu: convert to yaml

Now that we have the DT validation in place, let's convert the device tree
bindings for the Amlogic MHU controller over to a YAML schemas.
Reviewed-by: Rob Herring <robh@kernel.org>
Signed-off-by: Neil Armstrong <narmstrong@baylibre.com>
Signed-off-by: Rob Herring <robh@kernel.org>

Documentation/devicetree/bindings/mailbox/amlogic,meson-gxbb-mhu.yaml

+# SPDX-License-Identifier: (GPL-2.0 OR BSD-2-Clause)
+# Copyright 2019 BayLibre, SAS
+%YAML 1.2
+---
+$id: "http://devicetree.org/schemas/mailbox/amlogic,meson-gxbb-mhu.yaml#"
+$schema: "http://devicetree.org/meta-schemas/core.yaml#"
+
+title: Amlogic Meson Message-Handling-Unit Controller
+
+maintainers:
+  - Neil Armstrong <narmstrong@baylibre.com>
+
+description: |
+  The Amlogic's Meson SoCs 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.
+
+properties:
+  compatible:
+    enum:
+      - amlogic,meson-gxbb-mhu
+
+  reg:
+    maxItems: 1
+
+  interrupts:
+    minItems: 3
+    description:
+      Contains the interrupt information corresponding to each of the 3 links
+      of MHU.
+
+  "#mbox-cells":
+    const: 1
+
+required:
+  - compatible
+  - reg
+  - interrupts
+  - "#mbox-cells"
+
+examples:
+  - |
+    mailbox@c883c404 {
+          compatible = "amlogic,meson-gxbb-mhu";
+          reg = <0xc883c404 0x4c>;
+          interrupts = <208>, <209>, <210>;
+          #mbox-cells = <1>;
+    };
+

Documentation/devicetree/bindings/mailbox/meson-mhu.txt

-Amlogic Meson MHU Mailbox Driver
-================================
-
-The Amlogic's Meson SoCs 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.
-
-Mailbox Device Node:
-====================
-
-Required properties:
---------------------
-- compatible:		Shall be "amlogic,meson-gxbb-mhu"
-- 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 2 links of MHU.
-
-Example:
---------
-
-	mailbox: mailbox@c883c404 {
-		#mbox-cells = <1>;
-		compatible = "amlogic,meson-gxbb-mhu";
-		reg = <0 0xc883c404 0 0x4c>;
-		interrupts = <0 208 IRQ_TYPE_EDGE_RISING>,
-			     <0 209 IRQ_TYPE_EDGE_RISING>,
-			     <0 210 IRQ_TYPE_EDGE_RISING>;
-		#mbox-cells = <1>;
-	};