diff --git a/kasa/cli.py b/kasa/cli.py
index 66eb8936..317bf038 100755
--- a/kasa/cli.py
+++ b/kasa/cli.py
@@ -39,6 +39,7 @@ from kasa.iot import (
     IotStrip,
     IotWallSwitch,
 )
+from kasa.iot.modules import Usage
 from kasa.smart import SmartBulb, SmartDevice
 
 try:
@@ -829,7 +830,7 @@ async def usage(dev: Device, year, month, erase):
     Daily and monthly data provided in CSV format.
     """
     echo("[bold]== Usage ==[/bold]")
-    usage = dev.modules["usage"]
+    usage = cast(Usage, dev.modules["usage"])
 
     if erase:
         echo("Erasing usage statistics..")
diff --git a/kasa/device.py b/kasa/device.py
index dda7822f..8a81030f 100644
--- a/kasa/device.py
+++ b/kasa/device.py
@@ -15,6 +15,7 @@ from .emeterstatus import EmeterStatus
 from .exceptions import KasaException
 from .feature import Feature
 from .iotprotocol import IotProtocol
+from .module import Module
 from .protocol import BaseProtocol
 from .xortransport import XorTransport
 
@@ -72,7 +73,6 @@ class Device(ABC):
         self._last_update: Any = None
         self._discovery_info: dict[str, Any] | None = None
 
-        self.modules: dict[str, Any] = {}
         self._features: dict[str, Feature] = {}
         self._parent: Device | None = None
         self._children: Mapping[str, Device] = {}
@@ -111,6 +111,11 @@ class Device(ABC):
         """Disconnect and close any underlying connection resources."""
         await self.protocol.close()
 
+    @property
+    @abstractmethod
+    def modules(self) -> Mapping[str, Module]:
+        """Return the device modules."""
+
     @property
     @abstractmethod
     def is_on(self) -> bool:
diff --git a/kasa/iot/iotdevice.py b/kasa/iot/iotdevice.py
index d4551d0d..81b5edda 100755
--- a/kasa/iot/iotdevice.py
+++ b/kasa/iot/iotdevice.py
@@ -19,7 +19,7 @@ import functools
 import inspect
 import logging
 from datetime import datetime, timedelta
-from typing import Any, Mapping, Sequence
+from typing import Any, Mapping, Sequence, cast
 
 from ..device import Device, WifiNetwork
 from ..deviceconfig import DeviceConfig
@@ -28,7 +28,7 @@ from ..exceptions import KasaException
 from ..feature import Feature
 from ..protocol import BaseProtocol
 from .iotmodule import IotModule
-from .modules import Emeter
+from .modules import Emeter, Time
 
 _LOGGER = logging.getLogger(__name__)
 
@@ -189,12 +189,18 @@ class IotDevice(Device):
         self._supported_modules: dict[str, IotModule] | None = None
         self._legacy_features: set[str] = set()
         self._children: Mapping[str, IotDevice] = {}
+        self._modules: dict[str, IotModule] = {}
 
     @property
     def children(self) -> Sequence[IotDevice]:
         """Return list of children."""
         return list(self._children.values())
 
+    @property
+    def modules(self) -> dict[str, IotModule]:
+        """Return the device modules."""
+        return self._modules
+
     def add_module(self, name: str, module: IotModule):
         """Register a module."""
         if name in self.modules:
@@ -420,31 +426,31 @@ class IotDevice(Device):
         """Set the device name (alias)."""
         return await self._query_helper("system", "set_dev_alias", {"alias": alias})
 
-    @property  # type: ignore
+    @property
     @requires_update
     def time(self) -> datetime:
         """Return current time from the device."""
-        return self.modules["time"].time
+        return cast(Time, self.modules["time"]).time
 
-    @property  # type: ignore
+    @property
     @requires_update
     def timezone(self) -> dict:
         """Return the current timezone."""
-        return self.modules["time"].timezone
+        return cast(Time, self.modules["time"]).timezone
 
     async def get_time(self) -> datetime | None:
         """Return current time from the device, if available."""
         _LOGGER.warning(
             "Use `time` property instead, this call will be removed in the future."
         )
-        return await self.modules["time"].get_time()
+        return await cast(Time, self.modules["time"]).get_time()
 
     async def get_timezone(self) -> dict:
         """Return timezone information."""
         _LOGGER.warning(
             "Use `timezone` property instead, this call will be removed in the future."
         )
-        return await self.modules["time"].get_timezone()
+        return await cast(Time, self.modules["time"]).get_timezone()
 
     @property  # type: ignore
     @requires_update
@@ -520,31 +526,31 @@ class IotDevice(Device):
         """
         return await self._query_helper("system", "set_mac_addr", {"mac": mac})
 
-    @property  # type: ignore
+    @property
     @requires_update
     def emeter_realtime(self) -> EmeterStatus:
         """Return current energy readings."""
         self._verify_emeter()
-        return EmeterStatus(self.modules["emeter"].realtime)
+        return EmeterStatus(cast(Emeter, self.modules["emeter"]).realtime)
 
     async def get_emeter_realtime(self) -> EmeterStatus:
         """Retrieve current energy readings."""
         self._verify_emeter()
-        return EmeterStatus(await self.modules["emeter"].get_realtime())
+        return EmeterStatus(await cast(Emeter, self.modules["emeter"]).get_realtime())
 
-    @property  # type: ignore
+    @property
     @requires_update
     def emeter_today(self) -> float | None:
         """Return today's energy consumption in kWh."""
         self._verify_emeter()
-        return self.modules["emeter"].emeter_today
+        return cast(Emeter, self.modules["emeter"]).emeter_today
 
-    @property  # type: ignore
+    @property
     @requires_update
     def emeter_this_month(self) -> float | None:
         """Return this month's energy consumption in kWh."""
         self._verify_emeter()
-        return self.modules["emeter"].emeter_this_month
+        return cast(Emeter, self.modules["emeter"]).emeter_this_month
 
     async def get_emeter_daily(
         self, year: int | None = None, month: int | None = None, kwh: bool = True
@@ -558,7 +564,9 @@ class IotDevice(Device):
         :return: mapping of day of month to value
         """
         self._verify_emeter()
-        return await self.modules["emeter"].get_daystat(year=year, month=month, kwh=kwh)
+        return await cast(Emeter, self.modules["emeter"]).get_daystat(
+            year=year, month=month, kwh=kwh
+        )
 
     @requires_update
     async def get_emeter_monthly(
@@ -571,13 +579,15 @@ class IotDevice(Device):
         :return: dict: mapping of month to value
         """
         self._verify_emeter()
-        return await self.modules["emeter"].get_monthstat(year=year, kwh=kwh)
+        return await cast(Emeter, self.modules["emeter"]).get_monthstat(
+            year=year, kwh=kwh
+        )
 
     @requires_update
     async def erase_emeter_stats(self) -> dict:
         """Erase energy meter statistics."""
         self._verify_emeter()
-        return await self.modules["emeter"].erase_stats()
+        return await cast(Emeter, self.modules["emeter"]).erase_stats()
 
     @requires_update
     async def current_consumption(self) -> float:
diff --git a/kasa/iot/iotstrip.py b/kasa/iot/iotstrip.py
index 99f5913d..9e99a074 100755
--- a/kasa/iot/iotstrip.py
+++ b/kasa/iot/iotstrip.py
@@ -253,7 +253,7 @@ class IotStripPlug(IotPlug):
         self._last_update = parent._last_update
         self._set_sys_info(parent.sys_info)
         self._device_type = DeviceType.StripSocket
-        self.modules = {}
+        self._modules = {}
         self.protocol = parent.protocol  # Must use the same connection as the parent
         self.add_module("time", Time(self, "time"))
 
diff --git a/kasa/module.py b/kasa/module.py
index ad0b5562..213a2e0a 100644
--- a/kasa/module.py
+++ b/kasa/module.py
@@ -4,11 +4,14 @@ from __future__ import annotations
 
 import logging
 from abc import ABC, abstractmethod
+from typing import TYPE_CHECKING
 
-from .device import Device
 from .exceptions import KasaException
 from .feature import Feature
 
+if TYPE_CHECKING:
+    from .device import Device
+
 _LOGGER = logging.getLogger(__name__)
 
 
diff --git a/kasa/smart/smartdevice.py b/kasa/smart/smartdevice.py
index b325614b..80528fe4 100644
--- a/kasa/smart/smartdevice.py
+++ b/kasa/smart/smartdevice.py
@@ -47,7 +47,8 @@ class SmartDevice(Device):
         self._components_raw: dict[str, Any] | None = None
         self._components: dict[str, int] = {}
         self._state_information: dict[str, Any] = {}
-        self.modules: dict[str, SmartModule] = {}
+        self._modules: dict[str, SmartModule] = {}
+        self._exposes_child_modules = False
         self._parent: SmartDevice | None = None
         self._children: Mapping[str, SmartDevice] = {}
         self._last_update = {}
@@ -84,11 +85,13 @@ class SmartDevice(Device):
     @property
     def children(self) -> Sequence[SmartDevice]:
         """Return list of children."""
-        # Wall switches with children report all modules on the parent only
-        if self.device_type == DeviceType.WallSwitch:
-            return []
         return list(self._children.values())
 
+    @property
+    def modules(self) -> dict[str, SmartModule]:
+        """Return the device modules."""
+        return self._modules
+
     def _try_get_response(self, responses: dict, request: str, default=None) -> dict:
         response = responses.get(request)
         if isinstance(response, SmartErrorCode):
@@ -148,7 +151,7 @@ class SmartDevice(Device):
         req: dict[str, Any] = {}
 
         # TODO: this could be optimized by constructing the query only once
-        for module in self.modules.values():
+        for module in self._modules.values():
             req.update(module.query())
 
         self._last_update = resp = await self.protocol.query(req)
@@ -174,19 +177,24 @@ class SmartDevice(Device):
         # Some wall switches (like ks240) are internally presented as having child
         # devices which report the child's components on the parent's sysinfo, even
         # when they need to be accessed through the children.
-        # The logic below ensures that such devices report all but whitelisted, the
-        # child modules at the parent level to create an illusion of a single device.
+        # The logic below ensures that such devices add all but whitelisted, only on
+        # the child device.
+        skip_parent_only_modules = False
+        child_modules_to_skip = {}
         if self._parent and self._parent.device_type == DeviceType.WallSwitch:
-            modules = self._parent.modules
             skip_parent_only_modules = True
-        else:
-            modules = self.modules
-            skip_parent_only_modules = False
+        elif self._children and self.device_type == DeviceType.WallSwitch:
+            # _initialize_modules is called on the parent after the children
+            self._exposes_child_modules = True
+            for child in self._children.values():
+                child_modules_to_skip.update(**child.modules)
 
         for mod in SmartModule.REGISTERED_MODULES.values():
             _LOGGER.debug("%s requires %s", mod, mod.REQUIRED_COMPONENT)
 
-            if skip_parent_only_modules and mod in WALL_SWITCH_PARENT_ONLY_MODULES:
+            if (
+                skip_parent_only_modules and mod in WALL_SWITCH_PARENT_ONLY_MODULES
+            ) or mod.__name__ in child_modules_to_skip:
                 continue
             if mod.REQUIRED_COMPONENT in self._components:
                 _LOGGER.debug(
@@ -195,8 +203,11 @@ class SmartDevice(Device):
                     mod.__name__,
                 )
                 module = mod(self, mod.REQUIRED_COMPONENT)
-                if module.name not in modules and await module._check_supported():
-                    modules[module.name] = module
+                if await module._check_supported():
+                    self._modules[module.name] = module
+
+        if self._exposes_child_modules:
+            self._modules.update(**child_modules_to_skip)
 
     async def _initialize_features(self):
         """Initialize device features."""
@@ -278,7 +289,7 @@ class SmartDevice(Device):
                 )
             )
 
-        for module in self.modules.values():
+        for module in self._modules.values():
             for feat in module._module_features.values():
                 self._add_feature(feat)
 
diff --git a/kasa/tests/smart/modules/test_fan.py b/kasa/tests/smart/modules/test_fan.py
index 559ffefe..41d5706c 100644
--- a/kasa/tests/smart/modules/test_fan.py
+++ b/kasa/tests/smart/modules/test_fan.py
@@ -1,6 +1,9 @@
+from typing import cast
+
 from pytest_mock import MockerFixture
 
 from kasa import SmartDevice
+from kasa.smart.modules import FanModule
 from kasa.tests.device_fixtures import parametrize
 
 fan = parametrize("has fan", component_filter="fan_control", protocol_filter={"SMART"})
@@ -9,7 +12,7 @@ fan = parametrize("has fan", component_filter="fan_control", protocol_filter={"S
 @fan
 async def test_fan_speed(dev: SmartDevice, mocker: MockerFixture):
     """Test fan speed feature."""
-    fan = dev.modules.get("FanModule")
+    fan = cast(FanModule, dev.modules.get("FanModule"))
     assert fan
 
     level_feature = fan._module_features["fan_speed_level"]
@@ -32,7 +35,7 @@ async def test_fan_speed(dev: SmartDevice, mocker: MockerFixture):
 @fan
 async def test_sleep_mode(dev: SmartDevice, mocker: MockerFixture):
     """Test sleep mode feature."""
-    fan = dev.modules.get("FanModule")
+    fan = cast(FanModule, dev.modules.get("FanModule"))
     assert fan
     sleep_feature = fan._module_features["fan_sleep_mode"]
     assert isinstance(sleep_feature.value, bool)
diff --git a/kasa/tests/test_smartdevice.py b/kasa/tests/test_smartdevice.py
index 037edaf9..2b39e105 100644
--- a/kasa/tests/test_smartdevice.py
+++ b/kasa/tests/test_smartdevice.py
@@ -103,22 +103,22 @@ async def test_negotiate(dev: SmartDevice, mocker: MockerFixture):
 async def test_update_module_queries(dev: SmartDevice, mocker: MockerFixture):
     """Test that the regular update uses queries from all supported modules."""
     # We need to have some modules initialized by now
-    assert dev.modules
+    assert dev._modules
 
     device_queries: dict[SmartDevice, dict[str, Any]] = {}
-    for mod in dev.modules.values():
+    for mod in dev._modules.values():
         device_queries.setdefault(mod._device, {}).update(mod.query())
 
     spies = {}
-    for dev in device_queries:
-        spies[dev] = mocker.spy(dev.protocol, "query")
+    for device in device_queries:
+        spies[device] = mocker.spy(device.protocol, "query")
 
     await dev.update()
-    for dev in device_queries:
-        if device_queries[dev]:
-            spies[dev].assert_called_with(device_queries[dev])
+    for device in device_queries:
+        if device_queries[device]:
+            spies[device].assert_called_with(device_queries[device])
         else:
-            spies[dev].assert_not_called()
+            spies[device].assert_not_called()
 
 
 @bulb_smart