feat: Add support for MCP23016 IO Expander (#1012)

* feat: Add support for MCP23016 IO extander

* fix: Fix style

esphome/components/mcp23016/__init__.py

@@ -0,0 +1,50 @@
+import esphome.codegen as cg
+import esphome.config_validation as cv
+from esphome import pins
+from esphome.components import i2c
+from esphome.const import CONF_ID, CONF_NUMBER, CONF_MODE, CONF_INVERTED
+
+DEPENDENCIES = ['i2c']
+MULTI_CONF = True
+
+mcp23016_ns = cg.esphome_ns.namespace('mcp23016')
+MCP23016GPIOMode = mcp23016_ns.enum('MCP23016GPIOMode')
+MCP23016_GPIO_MODES = {
+    'INPUT': MCP23016GPIOMode.MCP23016_INPUT,
+    'OUTPUT': MCP23016GPIOMode.MCP23016_OUTPUT,
+}
+
+MCP23016 = mcp23016_ns.class_('MCP23016', cg.Component, i2c.I2CDevice)
+MCP23016GPIOPin = mcp23016_ns.class_('MCP23016GPIOPin', cg.GPIOPin)
+
+CONFIG_SCHEMA = cv.Schema({
+    cv.Required(CONF_ID): cv.declare_id(MCP23016),
+}).extend(cv.COMPONENT_SCHEMA).extend(i2c.i2c_device_schema(0x20))
+
+
+def to_code(config):
+    var = cg.new_Pvariable(config[CONF_ID])
+    yield cg.register_component(var, config)
+    yield i2c.register_i2c_device(var, config)
+
+
+CONF_MCP23016 = 'mcp23016'
+MCP23016_OUTPUT_PIN_SCHEMA = cv.Schema({
+    cv.Required(CONF_MCP23016): cv.use_id(MCP23016),
+    cv.Required(CONF_NUMBER): cv.int_,
+    cv.Optional(CONF_MODE, default="OUTPUT"): cv.enum(MCP23016_GPIO_MODES, upper=True),
+    cv.Optional(CONF_INVERTED, default=False): cv.boolean,
+})
+MCP23016_INPUT_PIN_SCHEMA = cv.Schema({
+    cv.Required(CONF_MCP23016): cv.use_id(MCP23016),
+    cv.Required(CONF_NUMBER): cv.int_,
+    cv.Optional(CONF_MODE, default="INPUT"): cv.enum(MCP23016_GPIO_MODES, upper=True),
+    cv.Optional(CONF_INVERTED, default=False): cv.boolean,
+})
+
+
+@pins.PIN_SCHEMA_REGISTRY.register(CONF_MCP23016,
+                                   (MCP23016_OUTPUT_PIN_SCHEMA, MCP23016_INPUT_PIN_SCHEMA))
+def mcp23016_pin_to_code(config):
+    parent = yield cg.get_variable(config[CONF_MCP23016])
+    yield MCP23016GPIOPin.new(parent, config[CONF_NUMBER], config[CONF_MODE], config[CONF_INVERTED])