dt-bindings: timer: Add schema for realtek,otto-timer

Add the devicetree schema for the realtek,otto-timer present on a number
of Realtek SoCs.
Signed-off-by: Chris Packham <chris.packham@alliedtelesis.co.nz>
Reviewed-by: Krzysztof Kozlowski <krzysztof.kozlowski@linaro.org>
Link: https://lore.kernel.org/r/20240710043524.1535151-6-chris.packham@alliedtelesis.co.nzSigned-off-by: Daniel Lezcano <daniel.lezcano@linaro.org>

Documentation/devicetree/bindings/timer/realtek,otto-timer.yaml

+# SPDX-License-Identifier: (GPL-2.0-only OR BSD-2-Clause)
+%YAML 1.2
+---
+$id: http://devicetree.org/schemas/timer/realtek,otto-timer.yaml#
+$schema: http://devicetree.org/meta-schemas/core.yaml#
+
+title: Realtek Otto SoCs Timer/Counter
+
+description:
+  Realtek SoCs support a number of timers/counters. These are used
+  as a per CPU clock event generator and an overall CPU clocksource.
+
+maintainers:
+  - Chris Packham <chris.packham@alliedtelesis.co.nz>
+
+properties:
+  $nodename:
+    pattern: "^timer@[0-9a-f]+$"
+
+  compatible:
+    items:
+      - enum:
+          - realtek,rtl9302-timer
+      - const: realtek,otto-timer
+
+  reg:
+    items:
+      - description: timer0 registers
+      - description: timer1 registers
+      - description: timer2 registers
+      - description: timer3 registers
+      - description: timer4 registers
+
+  clocks:
+    maxItems: 1
+
+  interrupts:
+    items:
+      - description: timer0 interrupt
+      - description: timer1 interrupt
+      - description: timer2 interrupt
+      - description: timer3 interrupt
+      - description: timer4 interrupt
+
+required:
+  - compatible
+  - reg
+  - clocks
+  - interrupts
+
+additionalProperties: false
+
+examples:
+  - |
+    timer@3200 {
+      compatible = "realtek,rtl9302-timer", "realtek,otto-timer";
+      reg = <0x3200 0x10>, <0x3210 0x10>, <0x3220 0x10>,
+            <0x3230 0x10>, <0x3240 0x10>;
+
+      interrupt-parent = <&intc>;
+      interrupts = <7>, <8>, <9>, <10>, <11>;
+      clocks = <&lx_clk>;
+    };