only allow one active call in each platform. (#52823)

.coveragerc

@@ -634,6 +634,9 @@ omit =
     homeassistant/components/mitemp_bt/sensor.py
     homeassistant/components/mjpeg/camera.py
     homeassistant/components/mochad/*
+    homeassistant/components/modbus/base_platform.py
+    homeassistant/components/modbus/binary_sensor.py
+    homeassistant/components/modbus/cover.py
     homeassistant/components/modbus/climate.py
     homeassistant/components/modbus/modbus.py
     homeassistant/components/modbus/validators.py

homeassistant/components/modbus/base_platform.py

@@ -56,6 +56,7 @@ class BasePlatform(Entity):
         self._value = None
         self._available = True
         self._scan_interval = int(entry[CONF_SCAN_INTERVAL])
+        self._call_active = False
 
     @abstractmethod
     async def async_update(self, now=None):
@@ -174,9 +175,14 @@ class BaseSwitch(BasePlatform, RestoreEntity):
             self.async_write_ha_state()
             return
 
+        # do not allow multiple active calls to the same platform
+        if self._call_active:
+            return
+        self._call_active = True
         result = await self._hub.async_pymodbus_call(
             self._slave, self._verify_address, 1, self._verify_type
         )
+        self._call_active = False
         if result is None:
             self._available = False
             self.async_write_ha_state()

homeassistant/components/modbus/binary_sensor.py

@@ -54,9 +54,15 @@ class ModbusBinarySensor(BasePlatform, RestoreEntity, BinarySensorEntity):
 
     async def async_update(self, now=None):
         """Update the state of the sensor."""
+
+        # do not allow multiple active calls to the same platform
+        if self._call_active:
+            return
+        self._call_active = True
         result = await self._hub.async_pymodbus_call(
             self._slave, self._address, 1, self._input_type
         )
+        self._call_active = False
         if result is None:
             self._available = False
             self.async_write_ha_state()

homeassistant/components/modbus/climate.py

@@ -194,13 +194,18 @@ class ModbusThermostat(BasePlatform, RestoreEntity, ClimateEntity):
         """Update Target & Current Temperature."""
         # remark "now" is a dummy parameter to avoid problems with
         # async_track_time_interval
+
+        # do not allow multiple active calls to the same platform
+        if self._call_active:
+            return
+        self._call_active = True
         self._target_temperature = await self._async_read_register(
             CALL_TYPE_REGISTER_HOLDING, self._target_temperature_register
         )
         self._current_temperature = await self._async_read_register(
             self._input_type, self._address
         )
-
+        self._call_active = False
         self.async_write_ha_state()
 
     async def _async_read_register(self, register_type, register) -> float | None:

homeassistant/components/modbus/cover.py

@@ -149,9 +149,14 @@ class ModbusCover(BasePlatform, CoverEntity, RestoreEntity):
         """Update the state of the cover."""
         # remark "now" is a dummy parameter to avoid problems with
         # async_track_time_interval
+        # do not allow multiple active calls to the same platform
+        if self._call_active:
+            return
+        self._call_active = True
         result = await self._hub.async_pymodbus_call(
             self._slave, self._address, 1, self._input_type
         )
+        self._call_active = False
         if result is None:
             self._available = False
             self.async_write_ha_state()