esphome/tests/components/mcp23008/test.esp32.yaml

i2c:
  - id: i2c_mcp23008
    scl: 16
    sda: 17

mcp23008:
  id: mcp23008_hub

binary_sensor:
  - platform: gpio
    id: mcp23008_binary_sensor
    pin:
      mcp23xxx: mcp23008_hub
      number: 0
      mode: INPUT

switch:
  - platform: gpio
    id: mcp23008_switch
    pin:
      mcp23xxx: mcp23008_hub
      number: 1
      mode: OUTPUT