Fix wallbox sensor rounding (#73310)

homeassistant/components/wallbox/manifest.json

@@ -4,10 +4,6 @@
   "config_flow": true,
   "documentation": "https://www.home-assistant.io/integrations/wallbox",
   "requirements": ["wallbox==0.4.9"],
-  "ssdp": [],
-  "zeroconf": [],
-  "homekit": {},
-  "dependencies": [],
   "codeowners": ["@hesselonline"],
   "iot_class": "cloud_polling",
   "loggers": ["wallbox"]

homeassistant/components/wallbox/sensor.py

@@ -167,8 +167,12 @@ class WallboxSensor(WallboxEntity, SensorEntity):
 
     @property
     def native_value(self) -> StateType:
-        """Return the state of the sensor."""
-        if (sensor_round := self.entity_description.precision) is not None:
+        """Return the state of the sensor. Round the value when it, and the precision property are not None."""
+        if (
+            sensor_round := self.entity_description.precision
+        ) is not None and self.coordinator.data[
+            self.entity_description.key
+        ] is not None:
             return cast(
                 StateType,
                 round(self.coordinator.data[self.entity_description.key], sensor_round),