core/homeassistant/components/modbus/binary_sensor.py

"""Support for Modbus Coil sensors."""
import logging
from typing import Optional

import voluptuous as vol

from homeassistant.components.binary_sensor import (
    DEVICE_CLASSES_SCHEMA,
    PLATFORM_SCHEMA,
    BinarySensorDevice,
)
from homeassistant.const import CONF_DEVICE_CLASS, CONF_NAME, CONF_SLAVE
from homeassistant.helpers import config_validation as cv

from . import CONF_HUB, DEFAULT_HUB, DOMAIN as MODBUS_DOMAIN

_LOGGER = logging.getLogger(__name__)

CONF_COIL = "coil"
CONF_COILS = "coils"

PLATFORM_SCHEMA = PLATFORM_SCHEMA.extend(
    {
        vol.Required(CONF_COILS): [
            {
                vol.Required(CONF_COIL): cv.positive_int,
                vol.Required(CONF_NAME): cv.string,
                vol.Optional(CONF_DEVICE_CLASS): DEVICE_CLASSES_SCHEMA,
                vol.Optional(CONF_HUB, default=DEFAULT_HUB): cv.string,
                vol.Optional(CONF_SLAVE): cv.positive_int,
            }
        ]
    }
)


def setup_platform(hass, config, add_entities, discovery_info=None):
    """Set up the Modbus binary sensors."""
    sensors = []
    for coil in config.get(CONF_COILS):
        hub = hass.data[MODBUS_DOMAIN][coil.get(CONF_HUB)]
        sensors.append(
            ModbusCoilSensor(
                hub,
                coil.get(CONF_NAME),
                coil.get(CONF_SLAVE),
                coil.get(CONF_COIL),
                coil.get(CONF_DEVICE_CLASS),
            )
        )

    add_entities(sensors)


class ModbusCoilSensor(BinarySensorDevice):
    """Modbus coil sensor."""

    def __init__(self, hub, name, slave, coil, device_class):
        """Initialize the Modbus coil sensor."""
        self._hub = hub
        self._name = name
        self._slave = int(slave) if slave else None
        self._coil = int(coil)
        self._device_class = device_class
        self._value = None

    @property
    def name(self):
        """Return the name of the sensor."""
        return self._name

    @property
    def is_on(self):
        """Return the state of the sensor."""
        return self._value

    @property
    def device_class(self) -> Optional[str]:
        """Return the device class of the sensor."""
        return self._device_class

    def update(self):
        """Update the state of the sensor."""
        result = self._hub.read_coils(self._slave, self._coil, 1)
        try:
            self._value = result.bits[0]
        except AttributeError:
            _LOGGER.error(
                "No response from hub %s, slave %s, coil %s",
                self._hub.name,
                self._slave,
                self._coil,
            )