X-Git-Url: https://git.ayoreis.com/Adafruit_Blinka-hackapet.git/blobdiff_plain/90390bc7eb1ba6c1c3d5862816b3b121e3f6d5db..7390c76fa233e16fb45b9ec8ecbc7cb745274cb6:/src/adafruit_blinka/microcontroller/generic_linux/spi.py

diff --git a/src/adafruit_blinka/microcontroller/generic_linux/spi.py b/src/adafruit_blinka/microcontroller/generic_linux/spi.py
index 01b885b..6cce037 100755
--- a/src/adafruit_blinka/microcontroller/generic_linux/spi.py
+++ b/src/adafruit_blinka/microcontroller/generic_linux/spi.py
@@ -1,8 +1,14 @@
-import Adafruit_PureIO.spi as spi
-import time
+# SPDX-FileCopyrightText: 2021 Melissa LeBlanc-Williams for Adafruit Industries
+#
+# SPDX-License-Identifier: MIT
+"""Generic Linux SPI class using PureIO's SPI class"""
+from Adafruit_PureIO import spi
 from adafruit_blinka.agnostic import detector
 
+
 class SPI:
+    """SPI Class"""
+
     MSB = 0
     LSB = 1
     CPHA = 1
@@ -17,9 +23,24 @@ class SPI:
             self._spi = spi.SPI(device=portid)
         else:
             self._spi = spi.SPI(device=(portid, 0))
+        self.clock_pin = None
+        self.mosi_pin = None
+        self.miso_pin = None
+        self.chip = None
 
-    def init(self, baudrate=100000, polarity=0, phase=0, bits=8,
-                  firstbit=MSB, sck=None, mosi=None, miso=None):
+    # pylint: disable=too-many-arguments,unused-argument
+    def init(
+        self,
+        baudrate=100000,
+        polarity=0,
+        phase=0,
+        bits=8,
+        firstbit=MSB,
+        sck=None,
+        mosi=None,
+        miso=None,
+    ):
+        """Initialize SPI"""
         mode = 0
         if polarity:
             mode |= self.CPOL
@@ -35,70 +56,88 @@ class SPI:
         self.mosi_pin = mosi
         self.miso_pin = miso
 
+    # pylint: enable=too-many-arguments,unused-argument
+
+    # pylint: disable=unnecessary-pass
     def set_no_cs(self):
+        """Setting so that SPI doesn't automatically set the CS pin"""
         # No kernel seems to support this, so we're just going to pass
         pass
 
+    # pylint: enable=unnecessary-pass
+
     @property
     def frequency(self):
+        """Return the current baudrate"""
         return self.baudrate
 
     def write(self, buf, start=0, end=None):
-        if not buf:
+        """Write data from the buffer to SPI"""
+        if buf is None or len(buf) < 1:
             return
         if end is None:
             end = len(buf)
         try:
-            #self._spi.open(self._port, 0)
+            # self._spi.open(self._port, 0)
             self.set_no_cs()
             self._spi.max_speed_hz = self.baudrate
             self._spi.mode = self.mode
             self._spi.bits_per_word = self.bits
             self._spi.writebytes(buf[start:end])
-            #self._spi.close()
-        except FileNotFoundError as not_found:
+            # self._spi.close()
+        except FileNotFoundError:
             print("Could not open SPI device - check if SPI is enabled in kernel!")
             raise
 
     def readinto(self, buf, start=0, end=None, write_value=0):
-        if not buf:
+        """Read data from SPI and into the buffer"""
+        if buf is None or len(buf) < 1:
             return
         if end is None:
             end = len(buf)
         try:
-            #self._spi.open(self._port, 0)
-            #self.set_no_cs()
+            # self._spi.open(self._port, 0)
+            # self.set_no_cs()
             self._spi.max_speed_hz = self.baudrate
             self._spi.mode = self.mode
             self._spi.bits_per_word = self.bits
-            data = self._spi.transfer([write_value]*(end-start))
-            for i in range(end-start):  # 'readinto' the given buffer
-              buf[start+i] = data[i]
-            #self._spi.close()
-        except FileNotFoundError as not_found:
+            data = self._spi.transfer([write_value] * (end - start))
+            for i in range(end - start):  # 'readinto' the given buffer
+                buf[start + i] = data[i]
+            # self._spi.close()
+        except FileNotFoundError:
             print("Could not open SPI device - check if SPI is enabled in kernel!")
             raise
 
-    def write_readinto(self, buffer_out, buffer_in, out_start=0,
-                       out_end=None, in_start=0, in_end=None):
-        if not buffer_out or not buffer_in:
+    # pylint: disable=too-many-arguments
+    def write_readinto(
+        self, buffer_out, buffer_in, out_start=0, out_end=None, in_start=0, in_end=None
+    ):
+        """Perform a half-duplex write from buffer_out and then
+        read data into buffer_in
+        """
+        if buffer_out is None or buffer_in is None:
+            return
+        if len(buffer_out) < 1 or len(buffer_in) < 1:
             return
         if out_end is None:
             out_end = len(buffer_out)
         if in_end is None:
             in_end = len(buffer_in)
         if out_end - out_start != in_end - in_start:
-            raise RuntimeError('Buffer slices must be of equal length.')
+            raise RuntimeError("Buffer slices must be of equal length.")
         try:
-            #self._spi.open(self._port, 0)
-            #self.set_no_cs()
+            # self._spi.open(self._port, 0)
+            # self.set_no_cs()
             self._spi.max_speed_hz = self.baudrate
             self._spi.mode = self.mode
             self._spi.bits_per_word = self.bits
-            data = self._spi.transfer(list(buffer_out[out_start:out_end+1]))
+            data = self._spi.transfer(list(buffer_out[out_start : out_end + 1]))
             for i in range((in_end - in_start)):
-                buffer_in[i+in_start] = data[i]
-            #self._spi.close()
-        except FileNotFoundError as not_found:
+                buffer_in[i + in_start] = data[i]
+            # self._spi.close()
+        except FileNotFoundError:
             print("Could not open SPI device - check if SPI is enabled in kernel!")
             raise
+
+    # pylint: enable=too-many-arguments