new file mode 100644
@@ -0,0 +1,42 @@
+# SPDX-License-Identifier: (GPL-2.0-only OR BSD-2-Clause)
+%YAML 1.2
+---
+$id: http://devicetree.org/schemas/mfd/qnap,ts433-mcu.yaml#
+$schema: http://devicetree.org/meta-schemas/core.yaml#
+
+title: QNAP NAS on-board Microcontroller
+
+maintainers:
+ - Heiko Stuebner <heiko@sntech.de>
+
+description:
+ QNAP embeds a microcontroller on their NAS devices adding system feature
+ as PWM Fan control, additional LEDs, power button status and more.
+
+properties:
+ compatible:
+ enum:
+ - qnap,ts433-mcu
+
+patternProperties:
+ "^fan-[0-9]+$":
+ $ref: /schemas/hwmon/fan-common.yaml#
+ unevaluatedProperties: false
+
+required:
+ - compatible
+
+additionalProperties: false
+
+examples:
+ - |
+ uart {
+ mcu {
+ compatible = "qnap,ts433-mcu";
+
+ fan-0 {
+ #cooling-cells = <2>;
+ cooling-levels = <0 64 89 128 166 204 221 238>;
+ };
+ };
+ };
These MCUs can be found in network attached storage devices made by QNAP. They are connected to a serial port of the host device and provide functionality like LEDs, power-control and temperature monitoring. LEDs, buttons, etc are all elements of the MCU firmware itself, so don't need devicetree input, though the fan gets its cooling settings from a fan-0 subnode. A binding for the LEDs for setting the linux-default-trigger may come later, once all the LEDs are understood and ATA controllers actually can address individual port-LEDs, but are really optional. Signed-off-by: Heiko Stuebner <heiko@sntech.de> --- .../bindings/mfd/qnap,ts433-mcu.yaml | 42 +++++++++++++++++++ 1 file changed, 42 insertions(+) create mode 100644 Documentation/devicetree/bindings/mfd/qnap,ts433-mcu.yaml