read actual values (untested)

sensor.py

@@ -1,25 +1,31 @@
-import time  # TODO remove
 import typing
 
+# circuitpython
+import busio
+import digitalio
+import adafruit_mcp3xxx.analog_in
+import adafruit_mcp3xxx.mcp3008
+
 import homeassistant.const
 import homeassistant.core
 import homeassistant.helpers.entity
 
 
 class MCP3008Channel(homeassistant.helpers.entity.Entity):
-    def __init__(self, channel_index: int) -> None:
-        self._channel_index = channel_index
+    def __init__(self, adc: adafruit_mcp3xxx.mcp3008.MCP3008, channel: int) -> None:
+        self._input = adafruit_mcp3xxx.analog_in.AnalogIn(adc, channel)
+        self._channel = channel
         self._state: typing.Optional[float] = None
 
     # https://developers.home-assistant.io/docs/core/entity/#generic-properties
 
     @property
     def name(self) -> str:
-        return f"MCP3008 Channel #{self._channel_index}"
+        return f"MCP3008 Channel #{self._channel}"
 
     @property
     def unique_id(self) -> str:
-        return f"mcp3008-ch{self._channel_index}"
+        return f"mcp3008-ch{self._channel}"
 
     # https://developers.home-assistant.io/docs/core/entity/sensor/#properties
 
@@ -36,7 +42,7 @@ class MCP3008Channel(homeassistant.helpers.entity.Entity):
         return homeassistant.const.VOLT
 
     def update(self) -> None:
-        self._state = (time.time() / 60) % 60  # TODO
+        self._state = self._input.voltage
 
 
 def setup_platform(
@@ -45,4 +51,24 @@ def setup_platform(
     add_entities: typing.Callable,
     discovery_info=None,
 ):
-    add_entities([MCP3008Channel(channel_index=0)])
+    board = __import__("board")  # raises NotImplementedError
+    spi = busio.SPI(clock=board.SCK, MISO=board.MISO, MOSI=board.MOSI)
+    spi_chip_select = digitalio.DigitalInOut(board.D5)
+    adc = adafruit_mcp3xxx.mcp3008.MCP3008(
+        spi_bus=spi, cs=spi_chip_select, ref_voltage=3.3
+    )
+    add_entities(
+        [
+            MCP3008Channel(adc=adc, channel=c)
+            for c in [
+                adafruit_mcp3xxx.mcp3008.P0,
+                adafruit_mcp3xxx.mcp3008.P1,
+                adafruit_mcp3xxx.mcp3008.P2,
+                adafruit_mcp3xxx.mcp3008.P3,
+                adafruit_mcp3xxx.mcp3008.P4,
+                adafruit_mcp3xxx.mcp3008.P5,
+                adafruit_mcp3xxx.mcp3008.P6,
+                adafruit_mcp3xxx.mcp3008.P7,
+            ]
+        ]
+    )