code style again

[Adafruit_Blinka-hackapet.git] / src / bitbangio.py

diff --git a/src/bitbangio.py b/src/bitbangio.py
index 2fefe60a4925e175ac148eabc1429f38ec7d16f6..d13b743a4a5f44c573be0ec9e1ad7db6b810a84b 100755 (executable)
--- a/src/bitbangio.py
+++ b/src/bitbangio.py
@@ -7,25 +7,40 @@ See `CircuitPython:bitbangio` in CircuitPython for more details.
 * Author(s): cefn
 """
 
-from adafruit_blinka import Lockable, agnostic
 import adafruit_platformdetect.constants.boards as ap_board
+from adafruit_blinka import Lockable, agnostic
+
+# pylint: disable=import-outside-toplevel,too-many-arguments
 
 
 class I2C(Lockable):
+    """Bitbang/Software I2C implementation"""
+
     def __init__(self, scl, sda, frequency=400000):
         # TODO: This one is a bit questionable:
         if agnostic.board_id == ap_board.PYBOARD:
             raise NotImplementedError("No software I2C on {}".format(agnostic.board_id))
+        if agnostic.detector.board.any_embedded_linux:
+            # TODO: Attempt to load this library automatically
+            raise NotImplementedError(
+                "For bitbangio on Linux, please use Adafruit_CircuitPython_BitbangIO"
+            )
         self.init(scl, sda, frequency)
 
     def init(self, scl, sda, frequency):
+        """Initialization"""
         from machine import Pin
         from machine import I2C as _I2C
+
         self.deinit()
-        id = -1  # force bitbanging implementation - in future introspect platform if SDA/SCL matches hardware I2C
+        id = (  # pylint: disable=redefined-builtin
+            -1
+        )  # force bitbanging implementation - in future
+        # introspect platform if SDA/SCL matches hardware I2C
         self._i2c = _I2C(id, Pin(scl.id), Pin(sda.id), freq=frequency)
 
     def deinit(self):
+        """Deinitialization"""
         try:
             del self._i2c
         except AttributeError:
@@ -38,10 +53,12 @@ class I2C(Lockable):
         self.deinit()
 
     def scan(self):
+        """Scan for attached devices"""
         return self._i2c.scan()
 
     def readfrom_into(self, address, buffer, start=0, end=None):
-        if start is not 0 or end is not None:
+        """Read from a device at specified address into a buffer"""
+        if start != 0 or end is not None:
             if end is None:
                 end = len(buffer)
             buffer = memoryview(buffer)[start:end]
@@ -49,43 +66,60 @@ class I2C(Lockable):
         return self._i2c.readfrom_into(address, buffer, stop)
 
     def writeto(self, address, buffer, start=0, end=None, stop=True):
-        if start is not 0 or end is not None:
+        """Write to a device at specified address from a buffer"""
+        if start != 0 or end is not None:
             if end is None:
                 return self._i2c.writeto(address, memoryview(buffer)[start:], stop)
-            else:
-                return self._i2c.writeto(address, memoryview(buffer)[start:end], stop)
+            return self._i2c.writeto(address, memoryview(buffer)[start:end], stop)
         return self._i2c.writeto(address, buffer, stop)
 
 
-# TODO untested, as actually busio.SPI was on tasklist https://github.com/adafruit/Adafruit_Micropython_Blinka/issues/2 :(
+# TODO untested, as actually busio.SPI was on
+# tasklist https://github.com/adafruit/Adafruit_Micropython_Blinka/issues/2 :(
 class SPI(Lockable):
+    """Bitbang/Software SPI implementation"""
+
     def __init__(self, clock, MOSI=None, MISO=None):
-        from machine import SPI
-        self._spi = SPI(-1)
+        if agnostic.detector.board.any_embedded_linux:
+            # TODO: Attempt to load this library automatically
+            raise NotImplementedError(
+                "For bitbangio on Linux, please use Adafruit_CircuitPython_BitbangIO"
+            )
+        from machine import SPI as _SPI
+
+        self._spi = _SPI(-1)
         self._pins = (clock, MOSI, MISO)
 
     def configure(self, baudrate=100000, polarity=0, phase=0, bits=8):
-        from machine import SPI,Pin
+        """Update the configuration"""
+        from machine import Pin
+        from machine import SPI as _SPI
+
         if self._locked:
-            # TODO verify if _spi obj 'caches' sck, mosi, miso to avoid storing in _attributeIds (duplicated in busio)
+            # TODO verify if _spi obj 'caches' sck, mosi, miso to
+            # avoid storing in _attributeIds (duplicated in busio)
             # i.e. #init ignores MOSI=None rather than unsetting
             self._spi.init(
                 baudrate=baudrate,
                 polarity=polarity,
                 phase=phase,
                 bits=bits,
-                firstbit=SPI.MSB,
+                firstbit=_SPI.MSB,
                 sck=Pin(self._pins[0].id),
                 mosi=Pin(self._pins[1].id),
-                miso=Pin(self._pins[2].id))
+                miso=Pin(self._pins[2].id),
+            )
         else:
             raise RuntimeError("First call try_lock()")
 
     def write(self, buf):
+        """Write to the SPI device"""
         return self._spi.write(buf)
 
     def readinto(self, buf):
+        """Read from the SPI device into a buffer"""
         return self.readinto(buf)
 
     def write_readinto(self, buffer_out, buffer_in):
+        """Write to the SPI device and read from the SPI device into a buffer"""
         return self.write_readinto(buffer_out, buffer_in)