dt-bindings: hwmon: fan: Add fan binding to schema

Add common fan properties bindings to a schema.

Bindings for fan controllers can reference the common schema for the
fan

child nodes:

patternProperties:
"^fan@[0-2]":
type: object
$ref: fan-common.yaml#
unevaluatedProperties: false

Reviewed-by: Rob Herring <[e-mail]>
Signed-off-by: Naresh Solanki <[e-mail]>
Signed-off-by: Billy Tsai <[e-mail]>
Link: https://lore.kernel.org/r/[e-mail]
Signed-off-by: Guenter Roeck <[e-mail]>

Documentation/devicetree/bindings/hwmon/fan-common.yaml

···
+# SPDX-License-Identifier: GPL-2.0-only OR BSD-2-Clause
+%YAML 1.2
+---
+$id: http://devicetree.org/schemas/hwmon/fan-common.yaml#
+$schema: http://devicetree.org/meta-schemas/core.yaml#
+
+title: Common Fan Properties
+
+maintainers:
+  - Naresh Solanki <[e-mail]>
+  - Billy Tsai <[e-mail]>
+
+properties:
+  max-rpm:
+    description:
+      Max RPM supported by fan.
+    $ref: /schemas/types.yaml#/definitions/uint32
+    maximum: 100000
+
+  min-rpm:
+    description:
+      Min RPM supported by fan.
+    $ref: /schemas/types.yaml#/definitions/uint32
+    maximum: 1000
+
+  pulses-per-revolution:
+    description:
+      The number of pulse from fan sensor per revolution.
+    $ref: /schemas/types.yaml#/definitions/uint32
+    maximum: 4
+
+  tach-div:
+    description:
+      Divisor for the tach sampling clock, which determines the sensitivity of the tach pin.
+    $ref: /schemas/types.yaml#/definitions/uint32
+
+  target-rpm:
+    description:
+      The default desired fan speed in RPM.
+    $ref: /schemas/types.yaml#/definitions/uint32
+
+  fan-driving-mode:
+    description:
+      Select the driving mode of the fan.(DC, PWM and so on)
+    $ref: /schemas/types.yaml#/definitions/string
+    enum: [ dc, pwm ]
+
+  pwms:
+    description:
+      PWM provider.
+    maxItems: 1
+
+  "#cooling-cells":
+    const: 2
+
+  cooling-levels:
+    description:
+      The control value which correspond to thermal cooling states.
+    $ref: /schemas/types.yaml#/definitions/uint32-array
+
+  tach-ch:
+    description:
+      The tach channel used for the fan.
+    $ref: /schemas/types.yaml#/definitions/uint8-array
+
+  label:
+    description:
+      Optional fan label
+
+  fan-supply:
+    description:
+      Power supply for fan.
+
+  reg:
+    maxItems: 1
+
+additionalProperties: true
+
+...