From 72b0c4b7bcb1383f0d195df6f69abd9bde199038 Mon Sep 17 00:00:00 2001
From: Franck Nijhof <git@frenck.dev>
Date: Fri, 28 Aug 2026 19:19:06 +0200
Subject: [PATCH] Honor the Modbus verify states for coils (#180490)

Co-authored-by: Copilot Autofix powered by AI <175728472+Copilot@users.noreply.github.com>
---
 homeassistant/components/modbus/entity.py | 31 ++++++++--------
 tests/components/modbus/test_switch.py    | 44 +++++++++++++++++++++++
 2 files changed, 60 insertions(+), 15 deletions(-)

diff --git a/homeassistant/components/modbus/entity.py b/homeassistant/components/modbus/entity.py
index 182251d0ce14..df7c3288230f 100644
--- a/homeassistant/components/modbus/entity.py
+++ b/homeassistant/components/modbus/entity.py
@@ -374,20 +374,21 @@ class ModbusToggleEntity(ModbusBaseEntity, ToggleEntity, RestoreEntity):
 
         self._attr_available = True
         if self._verify_type in (CALL_TYPE_COIL, CALL_TYPE_DISCRETE):
-            self._attr_is_on = bool(result.bits[0] & 1)
+            value = int(result.bits[0] & 1)
         else:
             value = int(result.registers[0])
-            if value in self._state_on:
-                self._attr_is_on = True
-            elif value in self._state_off:
-                self._attr_is_on = False
-            elif value is not None:
-                LOGGER.error(
-                    (
-                        "Unexpected response from modbus device slave %s register %s,"
-                        " got 0x%2x"
-                    ),
-                    self._device_address,
-                    self._verify_address,
-                    value,
-                )
+
+        if value in self._state_on:
+            self._attr_is_on = True
+        elif value in self._state_off:
+            self._attr_is_on = False
+        elif value is not None:
+            LOGGER.error(
+                (
+                    "Unexpected response from modbus device slave %s register %s,"
+                    " got 0x%2x"
+                ),
+                self._device_address,
+                self._verify_address,
+                value,
+            )
diff --git a/tests/components/modbus/test_switch.py b/tests/components/modbus/test_switch.py
index f9763e80307a..3175bb58cf98 100644
--- a/tests/components/modbus/test_switch.py
+++ b/tests/components/modbus/test_switch.py
@@ -478,6 +478,50 @@ async def test_service_switch_update(hass: HomeAssistant, mock_modbus_ha) -> Non
     assert hass.states.get(ENTITY_ID).state == STATE_ON
 
 
+@pytest.mark.parametrize(
+    "do_config",
+    [
+        {
+            CONF_SWITCHES: [
+                {
+                    CONF_NAME: TEST_ENTITY_NAME,
+                    CONF_ADDRESS: 1234,
+                    CONF_WRITE_TYPE: CALL_TYPE_COIL,
+                    CONF_COMMAND_ON: 0,
+                    CONF_COMMAND_OFF: 1,
+                    CONF_VERIFY: {
+                        CONF_STATE_ON: [0],
+                        CONF_STATE_OFF: [1],
+                    },
+                }
+            ]
+        },
+    ],
+)
+@pytest.mark.parametrize(
+    ("coil_value", "expected_state"),
+    [
+        (0x00, STATE_ON),
+        (0x01, STATE_OFF),
+    ],
+)
+async def test_switch_verify_coil_inverted(
+    hass: HomeAssistant,
+    mock_modbus_ha: mock.AsyncMock,
+    coil_value: int,
+    expected_state: str,
+) -> None:
+    """Run test for an inverted coil switch, where state_on is 0."""
+    mock_modbus_ha.read_coils.return_value = ReadResult([coil_value])
+    await hass.services.async_call(
+        HOMEASSISTANT_DOMAIN,
+        SERVICE_UPDATE_ENTITY,
+        {ATTR_ENTITY_ID: ENTITY_ID},
+        blocking=True,
+    )
+    assert hass.states.get(ENTITY_ID).state == expected_state
+
+
 @pytest.mark.parametrize(
     "do_config",
     [