Add Missing Type Annotations

adafruit_pcf8574.py

@@ -28,7 +28,8 @@
 
 try:
     # This is only needed for typing
-    import busio  # pylint: disable=unused-import
+    from typing import Optional
+    from busio import I2C
 except ImportError:
     pass
 
@@ -51,36 +52,34 @@ class PCF8574:
     :param int address: The I2C device address. Default is :const:`0x20`
     """
 
-    def __init__(
-        self, i2c_bus: busio.I2C, address: int = PCF8574_I2CADDR_DEFAULT
-    ) -> None:
+    def __init__(self, i2c_bus: I2C, address: int = PCF8574_I2CADDR_DEFAULT) -> None:
         self.i2c_device = I2CDevice(i2c_bus, address)
         self._writebuf = bytearray(1)
         self._writebuf[0] = 0
         self._readbuf = bytearray(1)
         self._readbuf[0] = 0
 
-    def get_pin(self, pin):
+    def get_pin(self, pin: int) -> "DigitalInOut":
         """Convenience function to create an instance of the DigitalInOut class
         pointing at the specified pin of this PCF8574 device.
         :param int pin: pin to use for digital IO, 0 to 7
         """
         assert 0 <= pin <= 7
         return DigitalInOut(pin, self)
 
-    def write_gpio(self, val):
+    def write_gpio(self, val: int) -> None:
         """Write a full 8-bit value to the GPIO register"""
         self._writebuf[0] = val & 0xFF
         with self.i2c_device as i2c:
             i2c.write(self._writebuf)
 
-    def read_gpio(self):
+    def read_gpio(self) -> int:
         """Read the full 8-bits of data from the GPIO register"""
         with self.i2c_device as i2c:
             i2c.readinto(self._readbuf)
         return self._readbuf[0]
 
-    def write_pin(self, pin, val):
+    def write_pin(self, pin: int, val: bool) -> None:
         """Set a single GPIO pin high/pulled-up or driven low"""
         if val:
             # turn on the pullup (write high)
@@ -89,7 +88,7 @@ def write_pin(self, pin, val):
             # turn on the transistor (write low)
             self.write_gpio(self._writebuf[0] & ~(1 << pin))
 
-    def read_pin(self, pin):
+    def read_pin(self, pin: int) -> bool:
         """Read a single GPIO pin as high/pulled-up or driven low"""
         return (self.read_gpio() >> pin) & 0x1
 
@@ -114,7 +113,7 @@ class DigitalInOut:
     configurations.
     """
 
-    def __init__(self, pin_number, pcf):
+    def __init__(self, pin_number: int, pcf: PCF8574) -> None:
         """Specify the pin number of the PCF8574 0..7, and instance."""
         self._pin = pin_number
         self._pcf = pcf
@@ -127,14 +126,14 @@ def __init__(self, pin_number, pcf):
     # is unused by this class).  Do not remove them, instead turn off pylint
     # in this case.
     # pylint: disable=unused-argument
-    def switch_to_output(self, value=False, **kwargs):
+    def switch_to_output(self, value: bool = False, **kwargs) -> None:
         """Switch the pin state to a digital output with the provided starting
         value (True/False for high or low, default is False/low).
         """
         self.direction = digitalio.Direction.OUTPUT
         self.value = value
 
-    def switch_to_input(self, pull=None, **kwargs):
+    def switch_to_input(self, pull: Optional[digitalio.Pull] = None, **kwargs) -> None:
         """Switch the pin state to a digital input which is the same as
         setting the light pullup on.  Note that true tri-state or
         pull-down resistors are NOT supported!
@@ -145,26 +144,26 @@ def switch_to_input(self, pull=None, **kwargs):
     # pylint: enable=unused-argument
 
     @property
-    def value(self):
+    def value(self) -> bool:
         """The value of the pin, either True for high/pulled-up or False for
         low.
         """
         return self._pcf.read_pin(self._pin)
 
     @value.setter
-    def value(self, val):
+    def value(self, val: bool) -> None:
         self._pcf.write_pin(self._pin, val)
 
     @property
-    def direction(self):
+    def direction(self) -> digitalio.Direction:
         """
         Setting a pin to OUTPUT drives it low, setting it to
         an INPUT enables the light pullup.
         """
         return self._dir
 
     @direction.setter
-    def direction(self, val):
+    def direction(self, val: digitalio.Direction) -> None:
         if val == digitalio.Direction.INPUT:
             # for inputs, turn on the pullup (write high)
             self._pcf.write_pin(self._pin, True)
@@ -177,14 +176,14 @@ def direction(self, val):
             raise ValueError("Expected INPUT or OUTPUT direction!")
 
     @property
-    def pull(self):
+    def pull(self) -> digitalio.Pull.UP:
         """
         Pull-up is always activated so always return the same thing
         """
         return digitalio.Pull.UP
 
     @pull.setter
-    def pull(self, val):
+    def pull(self, val: digitalio.Pull.UP) -> None:
         if val is digitalio.Pull.UP:
             # for inputs, turn on the pullup (write high)
             self._pcf.write_pin(self._pin, True)