dt-bindings: PWM: Add StarFive PWM module

Add documentation to describe StarFive Pulse Width Modulation
controller driver.

Signed-off-by: William Qiu <william.qiu@starfivetech.com>
Reviewed-by: Krzysztof Kozlowski <krzysztof.kozlowski@linaro.org>

diff --git a/Documentation/devicetree/bindings/pwm/starfive,jh7110-pwm.yaml b/Documentation/devicetree/bindings/pwm/starfive,jh7110-pwm.yaml
new file mode 100644 (file)
index 0000000..082b377
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+++ b/Documentation/devicetree/bindings/pwm/starfive,jh7110-pwm.yaml
@@ -0,0 +1,53 @@
+# SPDX-License-Identifier: GPL-2.0-only OR BSD-2-Clause
+%YAML 1.2
+---
+$id: http://devicetree.org/schemas/pwm/starfive,jh7110-pwm.yaml#
+$schema: http://devicetree.org/meta-schemas/core.yaml#
+
+title: StarFive PWM controller
+
+maintainers:
+  - William Qiu <william.qiu@starfivetech.com>
+
+description:
+  StarFive SoCs contain PWM and when operating in PWM mode, the PTC core generates
+  binary signal with user-programmable low and high periods. Clock source for the
+  PWM can be either system clockor external clock. Each PWM timer block provides 8
+  PWM channels.
+
+allOf:
+  - $ref: pwm.yaml#
+
+properties:
+  compatible:
+    const: starfive,jh7110-pwm
+
+  reg:
+    maxItems: 1
+
+  clocks:
+    maxItems: 1
+
+  resets:
+    maxItems: 1
+
+  "#pwm-cells":
+    const: 3
+
+required:
+  - compatible
+  - reg
+  - clocks
+  - resets
+
+additionalProperties: false
+
+examples:
+  - |
+    pwm@120d0000 {
+        compatible = "starfive,jh7110-pwm";
+        reg = <0x120d0000 0x10000>;
+        clocks = <&syscrg 121>;
+        resets = <&syscrg 108>;
+        #pwm-cells = <3>;
+    };