dt-bindings: timer: renesas,tpu: Convert to json-schema

Convert the Renesas H8/300 Timer Pulse Unit Device Tree binding
documentation to json-schema.

Correct clock-names, as "peripheral_clk" is the name of the supplier,
and all users use "fck".

Note that there are two different bindings for the TPU, both using
"renesas,tpu": this one for using the TPU as a clock source (used on
H8/300), and a second use for using the TPU as a PWM controller (used on
ARM).  To avoid conflicts, both bindings are marked with the appropriate
"select" logic, to check for the absence respectively presence of the
"#pwm-cells" property.

Signed-off-by: Geert Uytterhoeven <geert+renesas@glider.be>
Reviewed-by: Rob Herring <robh@kernel.org>
Acked-by: Yoshinori Sato <ysato@users.sourceforge.jp>
Link: https://lore.kernel.org/r/1c33e62c3a74979c3ca9580176e6cf89384caea9.1620648868.git.geert+renesas@glider.be
Signed-off-by: Rob Herring <robh@kernel.org>

Documentation/devicetree/bindings/pwm/renesas,tpu-pwm.yaml

@@ -9,6 +9,15 @@ title: Renesas R-Car Timer Pulse Unit PWM Controller
 maintainers:
   - Laurent Pinchart <laurent.pinchart+renesas@ideasonboard.com>
 
+select:
+  properties:
+    compatible:
+      contains:
+        const: renesas,tpu
+  required:
+    - compatible
+    - '#pwm-cells'
+
 properties:
   compatible:
     items:

Documentation/devicetree/bindings/timer/renesas,tpu.txt

@@ -1,21 +0,0 @@
-* Renesas H8/300 Timer Pulse Unit
-
-The TPU is a 16bit timer/counter with configurable clock inputs and
-programmable compare match.
-This implementation support only cascade mode.
-
-Required Properties:
-
-  - compatible: must contain "renesas,tpu"
-  - reg: base address and length of the registers block in 2 channel.
-  - clocks: a list of phandle, one for each entry in clock-names.
-  - clock-names: must contain "peripheral_clk" for the functional clock.
-
-
-Example:
-	tpu: tpu@ffffe0 {
-		compatible = "renesas,tpu";
-		reg = <0xffffe0 16>, <0xfffff0 12>;
-		clocks = <&pclk>;
-		clock-names = "peripheral_clk";
-	};

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

@@ -0,0 +1,56 @@
+# SPDX-License-Identifier: (GPL-2.0-only OR BSD-2-Clause)
+%YAML 1.2
+---
+$id: http://devicetree.org/schemas/timer/renesas,tpu.yaml#
+$schema: http://devicetree.org/meta-schemas/core.yaml#
+
+title: Renesas H8/300 Timer Pulse Unit
+
+maintainers:
+  - Yoshinori Sato <ysato@users.sourceforge.jp>
+
+description:
+  The TPU is a 16bit timer/counter with configurable clock inputs and
+  programmable compare match.
+  This implementation supports only cascade mode.
+
+select:
+  properties:
+    compatible:
+      contains:
+        const: renesas,tpu
+    '#pwm-cells': false
+  required:
+    - compatible
+
+properties:
+  compatible:
+    const: renesas,tpu
+
+  reg:
+    items:
+      - description: First channel
+      - description: Second channel
+
+  clocks:
+    maxItems: 1
+
+  clock-names:
+    const: fck
+
+required:
+  - compatible
+  - reg
+  - clocks
+  - clock-names
+
+additionalProperties: false
+
+examples:
+  - |
+    tpu: tpu@ffffe0 {
+            compatible = "renesas,tpu";
+            reg = <0xffffe0 16>, <0xfffff0 12>;
+            clocks = <&pclk>;
+            clock-names = "fck";
+    };