dt-bindings: soc: ti: wkup_m3_ipc: convert bindings to json-schema

Convert the wkup_m3_ipc bindings documentation to json-schema.

Link: https://lore.kernel.org/linux-arm-kernel/20220221125522.l3tntb6i7yjxp6vb@flattered/Suggested-by: Nishanth Menon <nm@ti.com>
Reviewed-by: Krzysztof Kozlowski <krzysztof.kozlowski@linaro.org>
Signed-off-by: Drew Fustini <dfustini@baylibre.com>
Signed-off-by: Rob Herring <robh@kernel.org>
Link: https://lore.kernel.org/r/20220407154618.2297171-1-dfustini@baylibre.com

Documentation/devicetree/bindings/soc/ti/wkup-m3-ipc.yaml

+# SPDX-License-Identifier: (GPL-2.0-only OR BSD-2-Clause)
+%YAML 1.2
+---
+$id: http://devicetree.org/schemas/soc/ti/wkup-m3-ipc.yaml#
+$schema: http://devicetree.org/meta-schemas/core.yaml#
+
+title: Wakeup M3 IPC device
+
+maintainers:
+  - Dave Gerlach <d-gerlach@ti.com>
+  - Drew Fustini <dfustini@baylibre.com>
+
+description: |+
+  The TI AM33xx and AM43xx family of devices use a small Cortex M3 co-processor
+  (commonly referred to as Wakeup M3 or CM3) to help with various low power tasks
+  that cannot be controlled from the MPU, like suspend/resume and certain deep
+  C-states for CPU Idle. Once the wkup_m3_ipc driver uses the wkup_m3_rproc driver
+  to boot the wkup_m3, it handles communication with the CM3 using IPC registers
+  present in the SoC's control module and a mailbox. The wkup_m3_ipc exposes an
+  API to allow the SoC PM code to execute specific PM tasks.
+
+  Wkup M3 Device Node
+  ====================
+  A wkup_m3_ipc device node is used to represent the IPC registers within an
+  SoC.
+
+properties:
+  compatible:
+    enum:
+      - ti,am3352-wkup-m3-ipc # for AM33xx SoCs
+      - ti,am4372-wkup-m3-ipc # for AM43xx SoCs
+
+  reg:
+    description:
+      The IPC register address space to communicate with the Wakeup M3 processor
+    maxItems: 1
+
+  interrupts:
+    description: wkup_m3 interrupt that signals the MPU
+    maxItems: 1
+
+  ti,rproc:
+    $ref: /schemas/types.yaml#/definitions/phandle
+    description:
+      phandle to the wkup_m3 rproc node so the IPC driver can boot it
+
+  mboxes:
+    description:
+      phandles used by IPC framework to get correct mbox
+      channel for communication. Must point to appropriate
+      mbox_wkupm3 child node.
+    maxItems: 1
+
+required:
+  - compatible
+  - reg
+  - interrupts
+  - ti,rproc
+  - mboxes
+
+additionalProperties: false
+
+examples:
+  - |
+    soc {
+        #address-cells = <1>;
+        #size-cells = <1>;
+
+        mailbox: mailbox {
+            #mbox-cells = <1>;
+        };
+
+        wkup_m3_ipc: wkup_m3_ipc@1324 {
+           compatible = "ti,am3352-wkup-m3-ipc";
+           reg = <0x1324 0x24>;
+           interrupts = <78>;
+           ti,rproc = <&wkup_m3>;
+           mboxes = <&mailbox &mbox_wkupm3>;
+        };
+    };
+...

Documentation/devicetree/bindings/soc/ti/wkup_m3_ipc.txt

-Wakeup M3 IPC Driver
-=====================
-
-The TI AM33xx and AM43xx family of devices use a small Cortex M3 co-processor
-(commonly referred to as Wakeup M3 or CM3) to help with various low power tasks
-that cannot be controlled from the MPU, like suspend/resume and certain deep
-C-states for CPU Idle. Once the wkup_m3_ipc driver uses the wkup_m3_rproc driver
-to boot the wkup_m3, it handles communication with the CM3 using IPC registers
-present in the SoC's control module and a mailbox. The wkup_m3_ipc exposes an
-API to allow the SoC PM code to execute specific PM tasks.
-
-Wkup M3 Device Node:
-====================
-A wkup_m3_ipc device node is used to represent the IPC registers within an
-SoC.
-
-Required properties:
---------------------
-- compatible:		Should be,
-				"ti,am3352-wkup-m3-ipc" for AM33xx SoCs
-				"ti,am4372-wkup-m3-ipc" for AM43xx SoCs
-- reg:			Contains the IPC register address space to communicate
-			with the Wakeup M3 processor
-- interrupts:		Contains the interrupt information for the wkup_m3
-			interrupt that signals the MPU.
-- ti,rproc:		phandle to the wkup_m3 rproc node so the IPC driver
-			can boot it.
-- mboxes:		phandles used by IPC framework to get correct mbox
-			channel for communication. Must point to appropriate
-			mbox_wkupm3 child node.
-
-Example:
---------
-/* AM33xx */
-	l4_wkup: l4_wkup@44c00000 {
-		...
-
-		scm: scm@210000 {
-			compatible = "ti,am3-scm", "simple-bus";
-			reg = <0x210000 0x2000>;
-			#address-cells = <1>;
-			#size-cells = <1>;
-			ranges = <0 0x210000 0x2000>;
-
-			...
-
-			wkup_m3_ipc: wkup_m3_ipc@1324 {
-				compatible = "ti,am3352-wkup-m3-ipc";
-				reg = <0x1324 0x24>;
-				interrupts = <78>;
-				ti,rproc = <&wkup_m3>;
-				mboxes = <&mailbox &mbox_wkupm3>;
-			};
-
-			...
-		};
-	};