dt-bindings: timer: renesas: tmu: Convert to json-schema

Convert the Renesas R-Mobile/R-Car Timer Unit (TMU) Device Tree binding
documentation to json-schema.

Document missing properties.
Update the example to match reality.

Signed-off-by: Geert Uytterhoeven <geert+renesas@glider.be>
Reviewed-by: Rob Herring <robh@kernel.org>
Signed-off-by: Daniel Lezcano <daniel.lezcano@linaro.org>
Reviewed-by: Niklas Söderlund <niklas.soderlund+renesas@ragnatech.se>
Link: https://lore.kernel.org/r/20201110162014.3290109-3-geert+renesas@glider.be

Documentation/devicetree/bindings/timer/renesas,tmu.yaml

@@ -0,0 +1,99 @@
+# SPDX-License-Identifier: (GPL-2.0-only OR BSD-2-Clause)
+%YAML 1.2
+---
+$id: http://devicetree.org/schemas/timer/renesas,tmu.yaml#
+$schema: http://devicetree.org/meta-schemas/core.yaml#
+
+title: Renesas R-Mobile/R-Car Timer Unit (TMU)
+
+maintainers:
+  - Geert Uytterhoeven <geert+renesas@glider.be>
+  - Laurent Pinchart <laurent.pinchart+renesas@ideasonboard.com>
+
+description:
+  The TMU is a 32-bit timer/counter with configurable clock inputs and
+  programmable compare match.
+
+  Channels share hardware resources but their counter and compare match value
+  are independent. The TMU hardware supports up to three channels.
+
+properties:
+  compatible:
+    items:
+      - enum:
+          - renesas,tmu-r8a7740  # R-Mobile A1
+          - renesas,tmu-r8a774a1 # RZ/G2M
+          - renesas,tmu-r8a774b1 # RZ/G2N
+          - renesas,tmu-r8a774c0 # RZ/G2E
+          - renesas,tmu-r8a774e1 # RZ/G2H
+          - renesas,tmu-r8a7778  # R-Car M1A
+          - renesas,tmu-r8a7779  # R-Car H1
+          - renesas,tmu-r8a77970 # R-Car V3M
+          - renesas,tmu-r8a77980 # R-Car V3H
+      - const: renesas,tmu
+
+  reg:
+    maxItems: 1
+
+  interrupts:
+    minItems: 2
+    maxItems: 3
+
+  clocks:
+    maxItems: 1
+
+  clock-names:
+    const: fck
+
+  power-domains:
+    maxItems: 1
+
+  resets:
+    maxItems: 1
+
+  '#renesas,channels':
+    description:
+      Number of channels implemented by the timer.
+    $ref: /schemas/types.yaml#/definitions/uint32
+    enum: [ 2, 3 ]
+    default: 3
+
+required:
+  - compatible
+  - reg
+  - interrupts
+  - clocks
+  - clock-names
+  - power-domains
+
+if:
+  not:
+    properties:
+      compatible:
+        contains:
+          enum:
+            - renesas,tmu-r8a7740
+            - renesas,tmu-r8a7778
+            - renesas,tmu-r8a7779
+then:
+  required:
+    - resets
+
+additionalProperties: false
+
+examples:
+  - |
+    #include <dt-bindings/clock/r8a7779-clock.h>
+    #include <dt-bindings/interrupt-controller/arm-gic.h>
+    #include <dt-bindings/power/r8a7779-sysc.h>
+    tmu0: timer@ffd80000 {
+            compatible = "renesas,tmu-r8a7779", "renesas,tmu";
+            reg = <0xffd80000 0x30>;
+            interrupts = <GIC_SPI 32 IRQ_TYPE_LEVEL_HIGH>,
+                         <GIC_SPI 33 IRQ_TYPE_LEVEL_HIGH>,
+                         <GIC_SPI 34 IRQ_TYPE_LEVEL_HIGH>;
+            clocks = <&mstp0_clks R8A7779_CLK_TMU0>;
+            clock-names = "fck";
+            power-domains = <&sysc R8A7779_PD_ALWAYS_ON>;
+            #renesas,channels = <3>;
+    };