dt-bindings: pwm: thead: Add T-HEAD TH1520 PWM controller

Add the Device Tree binding documentation for the T-HEAD
TH1520 SoC PWM controller.

Reviewed-by: Krzysztof Kozlowski <krzysztof.kozlowski@linaro.org>
Acked-by: Drew Fustini <fustini@kernel.org>
Reviewed-by: Elle Rhumsaa <elle@weathered-steel.dev>
Signed-off-by: Michal Wilczynski <m.wilczynski@samsung.com>
Link: https://patch.msgid.link/20251016-rust-next-pwm-working-fan-for-sending-v16-5-a5df2405d2bd@samsung.com
Signed-off-by: Uwe Kleine-König <ukleinek@kernel.org>

Documentation/devicetree/bindings/pwm/thead,th1520-pwm.yaml

@@ -0,0 +1,48 @@
+# SPDX-License-Identifier: (GPL-2.0-only OR BSD-2-Clause)
+%YAML 1.2
+---
+$id: http://devicetree.org/schemas/pwm/thead,th1520-pwm.yaml#
+$schema: http://devicetree.org/meta-schemas/core.yaml#
+
+title: T-HEAD TH1520 PWM controller
+
+maintainers:
+  - Michal Wilczynski <m.wilczynski@samsung.com>
+
+allOf:
+  - $ref: pwm.yaml#
+
+properties:
+  compatible:
+    const: thead,th1520-pwm
+
+  reg:
+    maxItems: 1
+
+  clocks:
+    items:
+      - description: SoC PWM clock
+
+  "#pwm-cells":
+    const: 3
+
+required:
+  - compatible
+  - reg
+  - clocks
+
+unevaluatedProperties: false
+
+examples:
+  - |
+    #include <dt-bindings/clock/thead,th1520-clk-ap.h>
+    soc {
+      #address-cells = <2>;
+      #size-cells = <2>;
+      pwm@ffec01c000 {
+          compatible = "thead,th1520-pwm";
+          reg = <0xff 0xec01c000 0x0 0x4000>;
+          clocks = <&clk CLK_PWM>;
+          #pwm-cells = <3>;
+      };
+    };

MAINTAINERS

@@ -22179,6 +22179,7 @@ F:	Documentation/devicetree/bindings/firmware/thead,th1520-aon.yaml
 F:	Documentation/devicetree/bindings/mailbox/thead,th1520-mbox.yaml
 F:	Documentation/devicetree/bindings/net/thead,th1520-gmac.yaml
 F:	Documentation/devicetree/bindings/pinctrl/thead,th1520-pinctrl.yaml
+F:	Documentation/devicetree/bindings/pwm/thead,th1520-pwm.yaml
 F:	Documentation/devicetree/bindings/reset/thead,th1520-reset.yaml
 F:	arch/riscv/boot/dts/thead/
 F:	drivers/clk/thead/clk-th1520-ap.c