dt-bindings: memory-controllers: renesas,dbsc: Convert to json-schema

Convert the Renesas DDR Bus Controller Device Tree binding documentation
to json-schema.

Drop referrals to driver behavior.
Make power-domains required, as it is present for all current users.
Update the example to match reality.
Signed-off-by: Geert Uytterhoeven <geert+renesas@glider.be>
Signed-off-by: Rob Herring <robh@kernel.org>

Documentation/devicetree/bindings/memory-controllers/renesas,dbsc.txt

-DT bindings for Renesas R-Mobile and SH-Mobile memory controllers
-=================================================================
-
-Renesas R-Mobile and SH-Mobile SoCs contain one or more memory controllers.
-These memory controllers differ from one SoC variant to another, and are called
-by different names ("DDR Bus Controller (DBSC)", "DDR3 Bus State Controller
-(DBSC3)", "SDRAM Bus State Controller (SBSC)").
-
-Currently memory controller device nodes are used only to reference PM
-domains, and prevent these PM domains from being powered down, which would
-crash the system.
-
-As there exist no actual drivers for these controllers yet, these bindings
-should be considered EXPERIMENTAL for now.
-
-Required properties:
-  - compatible: Must be one of the following SoC-specific values:
-		  - "renesas,dbsc-r8a73a4" (R-Mobile APE6)
-		  - "renesas,dbsc3-r8a7740" (R-Mobile A1)
-		  - "renesas,sbsc-sh73a0" (SH-Mobile AG5)
-  - reg: Must contain the base address and length of the memory controller's
-	 registers.
-
-Optional properties:
-  - interrupts: Must contain a list of interrupt specifiers for memory
-		controller interrupts, if available.
-  - interrupt-names: Must contain a list of interrupt names corresponding to
-		     the interrupts in the interrupts property, if available.
-		     Valid interrupt names are:
-			- "sec" (secure interrupt)
-			- "temp" (normal (temperature) interrupt)
-  - power-domains: Must contain a reference to the PM domain that the memory
-		   controller belongs to, if available.
-
-Example:
-
-	sbsc1: memory-controller@fe400000 {
-		compatible = "renesas,sbsc-sh73a0";
-		reg = <0xfe400000 0x400>;
-		interrupts = <0 35 IRQ_TYPE_LEVEL_HIGH>,
-			     <0 36 IRQ_TYPE_LEVEL_HIGH>;
-		interrupt-names = "sec", "temp";
-		power-domains = <&pd_a4bc0>;
-	};

Documentation/devicetree/bindings/memory-controllers/renesas,dbsc.yaml

+# SPDX-License-Identifier: (GPL-2.0-only OR BSD-2-Clause)
+%YAML 1.2
+---
+$id: "http://devicetree.org/schemas/memory-controllers/renesas,dbsc.yaml#"
+$schema: "http://devicetree.org/meta-schemas/core.yaml#"
+
+title: Renesas DDR Bus Controllers
+
+maintainers:
+  - Geert Uytterhoeven <geert+renesas@glider.be>
+
+description: |
+  Renesas SoCs contain one or more memory controllers.  These memory
+  controllers differ from one SoC variant to another, and are called by
+  different names, e.g. "DDR Bus Controller (DBSC)", "DDR3 Bus State Controller
+  (DBSC3)", or "SDRAM Bus State Controller (SBSC)").
+
+properties:
+  compatible:
+    enum:
+      - renesas,dbsc-r8a73a4  # R-Mobile APE6
+      - renesas,dbsc3-r8a7740 # R-Mobile A1
+      - renesas,sbsc-sh73a0   # SH-Mobile AG5
+
+  reg:
+    maxItems: 1
+
+  interrupts:
+    maxItems: 2
+
+  interrupt-names:
+    items:
+      - const: sec  # secure interrupt
+      - const: temp # normal (temperature) interrupt
+
+  power-domains:
+    maxItems: 1
+
+required:
+  - compatible
+  - reg
+  - power-domains
+
+additionalProperties: false
+
+examples:
+  - |
+    #include <dt-bindings/interrupt-controller/arm-gic.h>
+    sbsc1: memory-controller@fe400000 {
+            compatible = "renesas,sbsc-sh73a0";
+            reg = <0xfe400000 0x400>;
+            interrupts = <GIC_SPI 35 IRQ_TYPE_LEVEL_HIGH>,
+                         <GIC_SPI 36 IRQ_TYPE_LEVEL_HIGH>;
+            interrupt-names = "sec", "temp";
+            power-domains = <&pd_a4bc0>;
+    };