diff --git a/.pre-commit-config.yaml b/.pre-commit-config.yaml
index 1b9fadc..43d1385 100644
--- a/.pre-commit-config.yaml
+++ b/.pre-commit-config.yaml
@@ -24,7 +24,7 @@ repos:
         name: pylint (library code)
         types: [python]
         args:
-          - --disable=consider-using-f-string
+          - --disable=consider-using-f-string,duplicate-code
         exclude: "^(docs/|examples/|tests/|setup.py$)"
     -   id: pylint
         name: pylint (example code)
diff --git a/adafruit_motor/__init__.py b/adafruit_motor/__init__.py
index e69de29..639cfc7 100644
--- a/adafruit_motor/__init__.py
+++ b/adafruit_motor/__init__.py
@@ -0,0 +1,3 @@
+# SPDX-FileCopyrightText: 2021 Scott Shawcroft for Adafruit Industries
+#
+# SPDX-License-Identifier: MIT
diff --git a/adafruit_motor/motor.py b/adafruit_motor/motor.py
index 61f6253..63323d7 100644
--- a/adafruit_motor/motor.py
+++ b/adafruit_motor/motor.py
@@ -20,6 +20,13 @@
 * Author(s): Scott Shawcroft
 """
 
+try:
+    from typing import Optional, Type
+    from types import TracebackType
+    from pwmio import PWMOut
+except ImportError:
+    pass
+
 __version__ = "0.0.0-auto.0"
 __repo__ = "https://github.com/adafruit/Adafruit_CircuitPython_Motor.git"
 
@@ -48,14 +55,14 @@ class DCMotor:
     :param ~pwmio.PWMOut negative_pwm: The motor input that causes the motor to spin backwards
       when high and the other is low."""
 
-    def __init__(self, positive_pwm, negative_pwm):
+    def __init__(self, positive_pwm: PWMOut, negative_pwm: PWMOut) -> None:
         self._positive = positive_pwm
         self._negative = negative_pwm
         self._throttle = None
         self._decay_mode = FAST_DECAY
 
     @property
-    def throttle(self):
+    def throttle(self) -> Optional[float]:
         """Motor speed, ranging from -1.0 (full speed reverse) to 1.0 (full speed forward),
         or ``None`` (controller off).
         If ``None``, both PWMs are turned full off. If ``0.0``, both PWMs are turned full on.
@@ -63,7 +70,7 @@ def throttle(self):
         return self._throttle
 
     @throttle.setter
-    def throttle(self, value):
+    def throttle(self, value: Optional[float]) -> None:
         if value is not None and (value > 1.0 or value < -1.0):
             raise ValueError("Throttle must be None or between -1.0 and +1.0")
         self._throttle = value
@@ -91,14 +98,14 @@ def throttle(self, value):
                     self._negative.duty_cycle = 0
 
     @property
-    def decay_mode(self):
+    def decay_mode(self) -> int:
         """Motor controller recirculation current decay mode. A value of ``motor.FAST_DECAY``
         sets the motor controller to the default fast recirculation current decay mode
         (coasting); ``motor.SLOW_DECAY`` sets slow decay (braking) mode."""
         return self._decay_mode
 
     @decay_mode.setter
-    def decay_mode(self, mode=FAST_DECAY):
+    def decay_mode(self, mode: int = FAST_DECAY) -> None:
         if mode in (FAST_DECAY, SLOW_DECAY):
             self._decay_mode = mode
         else:
@@ -106,8 +113,13 @@ def decay_mode(self, mode=FAST_DECAY):
                 "Decay mode value must be either motor.FAST_DECAY or motor.SLOW_DECAY"
             )
 
-    def __enter__(self):
+    def __enter__(self) -> "DCMotor":
         return self
 
-    def __exit__(self, exception_type, exception_value, traceback):
+    def __exit__(
+        self,
+        exception_type: Optional[Type[type]],
+        exception_value: Optional[BaseException],
+        traceback: Optional[TracebackType],
+    ) -> None:
         self.throttle = None
diff --git a/adafruit_motor/servo.py b/adafruit_motor/servo.py
index 86e8d80..87d75a0 100644
--- a/adafruit_motor/servo.py
+++ b/adafruit_motor/servo.py
@@ -12,6 +12,14 @@
 * Author(s): Scott Shawcroft
 """
 
+try:
+    from typing import Optional, Type
+    from types import TracebackType
+    from pwmio import PWMOut
+except ImportError:
+    pass
+
+
 __version__ = "0.0.0-auto.0"
 __repo__ = "https://github.com/adafruit/Adafruit_CircuitPython_Motor.git"
 
@@ -24,18 +32,22 @@ class _BaseServo:  # pylint: disable-msg=too-few-public-methods
     :param int min_pulse: The minimum pulse length of the servo in microseconds.
     :param int max_pulse: The maximum pulse length of the servo in microseconds."""
 
-    def __init__(self, pwm_out, *, min_pulse=750, max_pulse=2250):
+    def __init__(
+        self, pwm_out: PWMOut, *, min_pulse: int = 750, max_pulse: int = 2250
+    ) -> None:
         self._pwm_out = pwm_out
         self.set_pulse_width_range(min_pulse, max_pulse)
 
-    def set_pulse_width_range(self, min_pulse=750, max_pulse=2250):
+    def set_pulse_width_range(
+        self, min_pulse: int = 750, max_pulse: int = 2250
+    ) -> None:
         """Change min and max pulse widths."""
         self._min_duty = int((min_pulse * self._pwm_out.frequency) / 1000000 * 0xFFFF)
         max_duty = (max_pulse * self._pwm_out.frequency) / 1000000 * 0xFFFF
         self._duty_range = int(max_duty - self._min_duty)
 
     @property
-    def fraction(self):
+    def fraction(self) -> Optional[float]:
         """Pulse width expressed as fraction between 0.0 (`min_pulse`) and 1.0 (`max_pulse`).
         For conventional servos, corresponds to the servo position as a fraction
         of the actuation range. Is None when servo is diabled (pulsewidth of 0ms).
@@ -45,7 +57,7 @@ def fraction(self):
         return (self._pwm_out.duty_cycle - self._min_duty) / self._duty_range
 
     @fraction.setter
-    def fraction(self, value):
+    def fraction(self, value: Optional[float]) -> None:
         if value is None:
             self._pwm_out.duty_cycle = 0  # disable the motor
             return
@@ -85,14 +97,21 @@ class Servo(_BaseServo):
          Test carefully to find the safe minimum and maximum.
     """
 
-    def __init__(self, pwm_out, *, actuation_range=180, min_pulse=750, max_pulse=2250):
+    def __init__(
+        self,
+        pwm_out: PWMOut,
+        *,
+        actuation_range: int = 180,
+        min_pulse: int = 750,
+        max_pulse: int = 2250
+    ) -> None:
         super().__init__(pwm_out, min_pulse=min_pulse, max_pulse=max_pulse)
         self.actuation_range = actuation_range
         """The physical range of motion of the servo in degrees."""
         self._pwm = pwm_out
 
     @property
-    def angle(self):
+    def angle(self) -> Optional[float]:
         """The servo angle in degrees. Must be in the range ``0`` to ``actuation_range``.
         Is None when servo is disabled."""
         if self.fraction is None:  # special case for disabled servos
@@ -100,7 +119,7 @@ def angle(self):
         return self.actuation_range * self.fraction
 
     @angle.setter
-    def angle(self, new_angle):
+    def angle(self, new_angle: Optional[int]) -> None:
         if new_angle is None:  # disable the servo by sending 0 signal
             self.fraction = None
             return
@@ -116,22 +135,27 @@ class ContinuousServo(_BaseServo):
     :param int max_pulse: The maximum pulse width of the servo in microseconds."""
 
     @property
-    def throttle(self):
+    def throttle(self) -> float:
         """How much power is being delivered to the motor. Values range from ``-1.0`` (full
         throttle reverse) to ``1.0`` (full throttle forwards.) ``0`` will stop the motor from
         spinning."""
         return self.fraction * 2 - 1
 
     @throttle.setter
-    def throttle(self, value):
+    def throttle(self, value: float) -> None:
         if value > 1.0 or value < -1.0:
             raise ValueError("Throttle must be between -1.0 and 1.0")
         if value is None:
             raise ValueError("Continuous servos cannot spin freely")
         self.fraction = (value + 1) / 2
 
-    def __enter__(self):
+    def __enter__(self) -> "ContinuousServo":
         return self
 
-    def __exit__(self, exception_type, exception_value, traceback):
+    def __exit__(
+        self,
+        exception_type: Optional[Type[type]],
+        exception_value: Optional[BaseException],
+        traceback: Optional[TracebackType],
+    ) -> None:
         self.throttle = 0
diff --git a/adafruit_motor/stepper.py b/adafruit_motor/stepper.py
index 83b702d..4bd8059 100755
--- a/adafruit_motor/stepper.py
+++ b/adafruit_motor/stepper.py
@@ -18,6 +18,13 @@
 
 from micropython import const
 
+try:
+    from typing import Union, Optional
+    from pwmio import PWMOut
+    from digitalio import DigitalInOut
+except ImportError:
+    pass
+
 __version__ = "0.0.0-auto.0"
 __repo__ = "https://github.com/adafruit/Adafruit_CircuitPython_Motor.git"
 
@@ -79,7 +86,15 @@ class StepperMotor:
     :param microsteps: set to `None`
     """
 
-    def __init__(self, ain1, ain2, bin1, bin2, *, microsteps=16):
+    def __init__(
+        self,
+        ain1: Union[PWMOut, DigitalInOut],
+        ain2: Union[PWMOut, DigitalInOut],
+        bin1: Union[PWMOut, DigitalInOut],
+        bin2: Union[PWMOut, DigitalInOut],
+        *,
+        microsteps: Optional[int] = 16
+    ) -> None:
         if microsteps is None:
             #
             # Digital IO Pins
@@ -107,7 +122,7 @@ def __init__(self, ain1, ain2, bin1, bin2, *, microsteps=16):
         self._microsteps = microsteps
         self._update_coils()
 
-    def _update_coils(self, *, microstepping=False):
+    def _update_coils(self, *, microstepping: bool = False) -> None:
         if self._microsteps is None:
             #
             # Digital IO Pins
@@ -144,7 +159,7 @@ def _update_coils(self, *, microstepping=False):
             for i in range(4):
                 self._coil[i].duty_cycle = duty_cycles[i]
 
-    def release(self):
+    def release(self) -> None:
         """Releases all the coils so the motor can free spin, also won't use any power"""
         # De-energize coils:
         for coil in self._coil:
@@ -153,9 +168,9 @@ def release(self):
             else:
                 coil.duty_cycle = 0
 
-    def onestep(
-        self, *, direction=FORWARD, style=SINGLE
-    ):  # pylint: disable=too-many-branches
+    def onestep(  # pylint: disable=too-many-branches
+        self, *, direction: int = FORWARD, style: int = SINGLE
+    ) -> None:
         """Performs one step of a particular style. The actual rotation amount will vary by style.
         `SINGLE` and `DOUBLE` will normal cause a full step rotation. `INTERLEAVE` will normally
         do a half step rotation. `MICROSTEP` will perform the smallest configured step.
diff --git a/docs/conf.py b/docs/conf.py
index 7b7bf65..e628522 100644
--- a/docs/conf.py
+++ b/docs/conf.py
@@ -43,6 +43,9 @@
 copyright = "2017 Scott Shawcroft"
 author = "Scott Shawcroft"
 
+# Ignore imports of these modules, which sphinx will not know about.
+autodoc_mock_imports = ["pwmio"]
+
 # The version info for the project you're documenting, acts as replacement for
 # |version| and |release|, also used in various other places throughout the
 # built documents.