diff --git a/homeassistant/components/firmata/light.py b/homeassistant/components/firmata/light.py
index de511058114..bec61172486 100644
--- a/homeassistant/components/firmata/light.py
+++ b/homeassistant/components/firmata/light.py
@@ -5,7 +5,7 @@ import logging
 
 from homeassistant.components.light import (
     ATTR_BRIGHTNESS,
-    SUPPORT_BRIGHTNESS,
+    COLOR_MODE_BRIGHTNESS,
     LightEntity,
 )
 from homeassistant.config_entries import ConfigEntry
@@ -56,6 +56,9 @@ async def async_setup_entry(
 class FirmataLight(FirmataPinEntity, LightEntity):
     """Representation of a light on a Firmata board."""
 
+    _attr_color_mode = COLOR_MODE_BRIGHTNESS
+    _attr_supported_color_modes = {COLOR_MODE_BRIGHTNESS}
+
     def __init__(
         self,
         api: FirmataBoardPin,
@@ -83,11 +86,6 @@ class FirmataLight(FirmataPinEntity, LightEntity):
         """Return the brightness of the light."""
         return self._api.state
 
-    @property
-    def supported_features(self) -> int:
-        """Flag supported features."""
-        return SUPPORT_BRIGHTNESS
-
     async def async_turn_on(self, **kwargs) -> None:
         """Turn on light."""
         level = kwargs.get(ATTR_BRIGHTNESS, self._last_on_level)