dts: bindings: pwm: add binding for the NEORV32 PWM controller

Add devicetree binding for the NEORV32 PWM controller.

Signed-off-by: Henrik Brix Andersen <[email protected]>

Author: henrikbrixandersen

dts/bindings/pwm/neorv32,pwm.yaml

@@ -0,0 +1,27 @@
+# Copyright (c) 2025 Henrik Brix Andersen <[email protected]>
+# SPDX-License-Identifier: Apache-2.0
+
+description: NEORV32 PWM
+
+compatible: "neorv32,pwm"
+
+include: [pwm-controller.yaml, base.yaml]
+
+properties:
+  reg:
+    required: true
+
+  syscon:
+    type: phandle
+    required: true
+    description: |
+      phandle to syscon (NEORV32 SYSINFO) node.
+
+  "#pwm-cells":
+    const: 3
+
+pwm-cells:
+  - channel
+  # period in terms of nanoseconds
+  - period
+  - flags