Add iot brightness feature (#808)

kasa/iot/iotdimmer.py

@@ -4,6 +4,7 @@ from typing import Any, Dict, Optional
 
 from ..device_type import DeviceType
 from ..deviceconfig import DeviceConfig
+from ..feature import Feature, FeatureType
 from ..protocol import BaseProtocol
 from .iotdevice import KasaException, requires_update
 from .iotplug import IotPlug
@@ -80,6 +81,22 @@ class IotDimmer(IotPlug):
         self.add_module("motion", Motion(self, "smartlife.iot.PIR"))
         self.add_module("ambient", AmbientLight(self, "smartlife.iot.LAS"))
 
+    async def _initialize_features(self):
+        await super()._initialize_features()
+
+        if "brightness" in self.sys_info:  # pragma: no branch
+            self._add_feature(
+                Feature(
+                    device=self,
+                    name="Brightness",
+                    attribute_getter="brightness",
+                    attribute_setter="set_brightness",
+                    minimum_value=1,
+                    maximum_value=100,
+                    type=FeatureType.Number,
+                )
+            )
+
     @property  # type: ignore
     @requires_update
     def brightness(self) -> int: