diff --git a/.pylintrc b/.pylintrc
index cfd1c41..3908316 100644
--- a/.pylintrc
+++ b/.pylintrc
@@ -55,7 +55,7 @@ confidence=
 # no Warning level messages displayed, use"--disable=all --enable=classes
 # --disable=W"
 # disable=import-error,print-statement,parameter-unpacking,unpacking-in-except,old-raise-syntax,backtick,long-suffix,old-ne-operator,old-octal-literal,import-star-module-level,raw-checker-failed,bad-inline-option,locally-disabled,locally-enabled,file-ignored,suppressed-message,useless-suppression,deprecated-pragma,apply-builtin,basestring-builtin,buffer-builtin,cmp-builtin,coerce-builtin,execfile-builtin,file-builtin,long-builtin,raw_input-builtin,reduce-builtin,standarderror-builtin,unicode-builtin,xrange-builtin,coerce-method,delslice-method,getslice-method,setslice-method,no-absolute-import,old-division,dict-iter-method,dict-view-method,next-method-called,metaclass-assignment,indexing-exception,raising-string,reload-builtin,oct-method,hex-method,nonzero-method,cmp-method,input-builtin,round-builtin,intern-builtin,unichr-builtin,map-builtin-not-iterating,zip-builtin-not-iterating,range-builtin-not-iterating,filter-builtin-not-iterating,using-cmp-argument,eq-without-hash,div-method,idiv-method,rdiv-method,exception-message-attribute,invalid-str-codec,sys-max-int,bad-python3-import,deprecated-string-function,deprecated-str-translate-call
-disable=print-statement,parameter-unpacking,unpacking-in-except,old-raise-syntax,backtick,long-suffix,old-ne-operator,old-octal-literal,import-star-module-level,raw-checker-failed,bad-inline-option,locally-disabled,locally-enabled,file-ignored,suppressed-message,useless-suppression,deprecated-pragma,apply-builtin,basestring-builtin,buffer-builtin,cmp-builtin,coerce-builtin,execfile-builtin,file-builtin,long-builtin,raw_input-builtin,reduce-builtin,standarderror-builtin,unicode-builtin,xrange-builtin,coerce-method,delslice-method,getslice-method,setslice-method,no-absolute-import,old-division,dict-iter-method,dict-view-method,next-method-called,metaclass-assignment,indexing-exception,raising-string,reload-builtin,oct-method,hex-method,nonzero-method,cmp-method,input-builtin,round-builtin,intern-builtin,unichr-builtin,map-builtin-not-iterating,zip-builtin-not-iterating,range-builtin-not-iterating,filter-builtin-not-iterating,using-cmp-argument,eq-without-hash,div-method,idiv-method,rdiv-method,exception-message-attribute,invalid-str-codec,sys-max-int,bad-python3-import,deprecated-string-function,deprecated-str-translate-call,import-error,bad-continuation,unspecified-encoding
+disable=print-statement,parameter-unpacking,unpacking-in-except,old-raise-syntax,backtick,long-suffix,old-ne-operator,old-octal-literal,import-star-module-level,raw-checker-failed,bad-inline-option,locally-disabled,locally-enabled,file-ignored,suppressed-message,useless-suppression,deprecated-pragma,apply-builtin,basestring-builtin,buffer-builtin,cmp-builtin,coerce-builtin,execfile-builtin,file-builtin,long-builtin,raw_input-builtin,reduce-builtin,standarderror-builtin,unicode-builtin,xrange-builtin,coerce-method,delslice-method,getslice-method,setslice-method,no-absolute-import,old-division,dict-iter-method,dict-view-method,next-method-called,metaclass-assignment,indexing-exception,raising-string,reload-builtin,oct-method,hex-method,nonzero-method,cmp-method,input-builtin,round-builtin,intern-builtin,unichr-builtin,map-builtin-not-iterating,zip-builtin-not-iterating,range-builtin-not-iterating,filter-builtin-not-iterating,using-cmp-argument,eq-without-hash,div-method,idiv-method,rdiv-method,exception-message-attribute,invalid-str-codec,sys-max-int,bad-python3-import,deprecated-string-function,deprecated-str-translate-call,import-error,bad-continuation,unspecified-encoding,duplicate-code
 
 # Enable the message, report, category or checker with the given id(s). You can
 # either give multiple identifier separated by comma (,) or put this option
diff --git a/adafruit_bus_device/i2c_device.py b/adafruit_bus_device/i2c_device.py
index 770f4c7..9c02b4b 100644
--- a/adafruit_bus_device/i2c_device.py
+++ b/adafruit_bus_device/i2c_device.py
@@ -7,6 +7,18 @@
 ====================================================
 """
 
+try:
+    from typing import Optional, Type
+    from types import TracebackType
+    from busio import I2C
+
+    try:
+        from circuitpython_typing import ReadableBuffer, WriteableBuffer
+    except ImportError:
+        from _typing import ReadableBuffer, WriteableBuffer
+except ImportError:
+    pass
+
 __version__ = "0.0.0-auto.0"
 __repo__ = "https://github.com/adafruit/Adafruit_CircuitPython_BusDevice.git"
 
@@ -41,7 +53,7 @@ class I2CDevice:
                 device.write(bytes_read)
     """
 
-    def __init__(self, i2c, device_address, probe=True):
+    def __init__(self, i2c: I2C, device_address: int, probe: bool = True) -> None:
 
         self.i2c = i2c
         self.device_address = device_address
@@ -49,7 +61,9 @@ def __init__(self, i2c, device_address, probe=True):
         if probe:
             self.__probe_for_device()
 
-    def readinto(self, buf, *, start=0, end=None):
+    def readinto(
+        self, buf: WriteableBuffer, *, start: int = 0, end: Optional[int] = None
+    ) -> None:
         """
         Read into ``buf`` from the device. The number of bytes read will be the
         length of ``buf``.
@@ -58,7 +72,7 @@ def readinto(self, buf, *, start=0, end=None):
         as if ``buf[start:end]``. This will not cause an allocation like
         ``buf[start:end]`` will so it saves memory.
 
-        :param bytearray buffer: buffer to write into
+        :param ~WriteableBuffer buffer: buffer to write into
         :param int start: Index to start writing at
         :param int end: Index to write up to but not include; if None, use ``len(buf)``
         """
@@ -66,7 +80,9 @@ def readinto(self, buf, *, start=0, end=None):
             end = len(buf)
         self.i2c.readfrom_into(self.device_address, buf, start=start, end=end)
 
-    def write(self, buf, *, start=0, end=None):
+    def write(
+        self, buf: ReadableBuffer, *, start: int = 0, end: Optional[int] = None
+    ) -> None:
         """
         Write the bytes from ``buffer`` to the device, then transmit a stop
         bit.
@@ -75,7 +91,7 @@ def write(self, buf, *, start=0, end=None):
         as if ``buffer[start:end]``. This will not cause an allocation like
         ``buffer[start:end]`` will so it saves memory.
 
-        :param bytearray buffer: buffer containing the bytes to write
+        :param ~ReadableBuffer buffer: buffer containing the bytes to write
         :param int start: Index to start writing from
         :param int end: Index to read up to but not include; if None, use ``len(buf)``
         """
@@ -86,14 +102,14 @@ def write(self, buf, *, start=0, end=None):
     # pylint: disable-msg=too-many-arguments
     def write_then_readinto(
         self,
-        out_buffer,
-        in_buffer,
+        out_buffer: ReadableBuffer,
+        in_buffer: WriteableBuffer,
         *,
-        out_start=0,
-        out_end=None,
-        in_start=0,
-        in_end=None
-    ):
+        out_start: int = 0,
+        out_end: Optional[int] = None,
+        in_start: int = 0,
+        in_end: Optional[int] = None
+    ) -> None:
         """
         Write the bytes from ``out_buffer`` to the device, then immediately
         reads into ``in_buffer`` from the device. The number of bytes read
@@ -109,8 +125,8 @@ def write_then_readinto(
         cause an allocation like ``in_buffer[in_start:in_end]`` will so
         it saves memory.
 
-        :param bytearray out_buffer: buffer containing the bytes to write
-        :param bytearray in_buffer: buffer containing the bytes to read into
+        :param ~ReadableBuffer out_buffer: buffer containing the bytes to write
+        :param ~WriteableBuffer in_buffer: buffer containing the bytes to read into
         :param int out_start: Index to start writing from
         :param int out_end: Index to read up to but not include; if None, use ``len(out_buffer)``
         :param int in_start: Index to start writing at
@@ -133,16 +149,21 @@ def write_then_readinto(
 
     # pylint: enable-msg=too-many-arguments
 
-    def __enter__(self):
+    def __enter__(self) -> "I2CDevice":
         while not self.i2c.try_lock():
             pass
         return self
 
-    def __exit__(self, exc_type, exc_val, exc_tb):
+    def __exit__(
+        self,
+        exc_type: Optional[Type[type]],
+        exc_val: Optional[BaseException],
+        exc_tb: Optional[TracebackType],
+    ) -> bool:
         self.i2c.unlock()
         return False
 
-    def __probe_for_device(self):
+    def __probe_for_device(self) -> None:
         """
         Try to read a byte from an address,
         if you get an OSError it means the device is not there
diff --git a/adafruit_bus_device/spi_device.py b/adafruit_bus_device/spi_device.py
index 3e20115..58c948c 100644
--- a/adafruit_bus_device/spi_device.py
+++ b/adafruit_bus_device/spi_device.py
@@ -9,6 +9,14 @@
 ====================================================
 """
 
+try:
+    from typing import Optional, Type
+    from types import TracebackType
+    from busio import SPI
+    from digitalio import DigitalInOut
+except ImportError:
+    pass
+
 __version__ = "0.0.0-auto.0"
 __repo__ = "https://github.com/adafruit/Adafruit_CircuitPython_BusDevice.git"
 
@@ -23,6 +31,9 @@ class SPIDevice:
         DigitalInOut API.
     :param bool cs_active_value: Set to true if your device requires CS to be active high.
         Defaults to false.
+    :param int baudrate: The SPI baudrate
+    :param int polarity: The SPI polarity
+    :param int phase: The SPI phase
     :param int extra_clocks: The minimum number of clock cycles to cycle the bus after CS is high.
         (Used for SD cards.)
 
@@ -54,15 +65,15 @@ class SPIDevice:
 
     def __init__(
         self,
-        spi,
-        chip_select=None,
+        spi: SPI,
+        chip_select: Optional[DigitalInOut] = None,
         *,
-        cs_active_value=False,
-        baudrate=100000,
-        polarity=0,
-        phase=0,
-        extra_clocks=0
-    ):
+        cs_active_value: bool = False,
+        baudrate: int = 100000,
+        polarity: int = 0,
+        phase: int = 0,
+        extra_clocks: int = 0
+    ) -> None:
         self.spi = spi
         self.baudrate = baudrate
         self.polarity = polarity
@@ -73,7 +84,7 @@ def __init__(
         if self.chip_select:
             self.chip_select.switch_to_output(value=True)
 
-    def __enter__(self):
+    def __enter__(self) -> SPI:
         while not self.spi.try_lock():
             pass
         self.spi.configure(
@@ -83,7 +94,12 @@ def __enter__(self):
             self.chip_select.value = self.cs_active_value
         return self.spi
 
-    def __exit__(self, exc_type, exc_val, exc_tb):
+    def __exit__(
+        self,
+        exc_type: Optional[Type[type]],
+        exc_val: Optional[BaseException],
+        exc_tb: Optional[TracebackType],
+    ) -> bool:
         if self.chip_select:
             self.chip_select.value = not self.cs_active_value
         if self.extra_clocks > 0:
diff --git a/docs/conf.py b/docs/conf.py
index eaa3bb1..42eb1b2 100644
--- a/docs/conf.py
+++ b/docs/conf.py
@@ -23,7 +23,7 @@
 # Uncomment the below if you use native CircuitPython modules such as
 # digitalio, micropython and busio. List the modules you use. Without it, the
 # autodoc module docs will fail to generate with a warning.
-# autodoc_mock_imports = ["adafruit_bus_device", "micropython"]
+autodoc_mock_imports = ["busio", "digitalio", "circuitpython_typing", "_typing"]
 
 intersphinx_mapping = {
     "python": ("https://docs.python.org/3", None),