core/homeassistant/components/modbus/binary_sensor.py

"""Support for Modbus Coil and Discrete Input sensors."""
from __future__ import annotations

from datetime import datetime

from homeassistant.components.binary_sensor import BinarySensorEntity
from homeassistant.const import CONF_BINARY_SENSORS, CONF_NAME, STATE_ON
from homeassistant.core import HomeAssistant
from homeassistant.helpers.entity_platform import AddEntitiesCallback
from homeassistant.helpers.restore_state import RestoreEntity
from homeassistant.helpers.typing import ConfigType, DiscoveryInfoType

from . import get_hub
from .base_platform import BasePlatform

PARALLEL_UPDATES = 1


async def async_setup_platform(
    hass: HomeAssistant,
    config: ConfigType,
    async_add_entities: AddEntitiesCallback,
    discovery_info: DiscoveryInfoType | None = None,
) -> None:
    """Set up the Modbus binary sensors."""
    sensors = []

    if discovery_info is None:  # pragma: no cover
        return

    for entry in discovery_info[CONF_BINARY_SENSORS]:
        hub = get_hub(hass, discovery_info[CONF_NAME])
        sensors.append(ModbusBinarySensor(hub, entry))

    async_add_entities(sensors)


class ModbusBinarySensor(BasePlatform, RestoreEntity, BinarySensorEntity):
    """Modbus binary sensor."""

    async def async_added_to_hass(self) -> None:
        """Handle entity which will be added."""
        await self.async_base_added_to_hass()
        state = await self.async_get_last_state()
        if state:
            self._attr_is_on = state.state == STATE_ON

    async def async_update(self, now: datetime | None = None) -> 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:
            if self._lazy_errors:
                self._lazy_errors -= 1
                return
            self._lazy_errors = self._lazy_error_count
            self._attr_available = False
            self.async_write_ha_state()
            return

        self._lazy_errors = self._lazy_error_count
        self._attr_is_on = result.bits[0] & 1
        self._attr_available = True
        self.async_write_ha_state()