Incorporating nmadura's BeagleBone changes

Author: PaintYourDragon

Adafruit_I2C/Adafruit_I2C.py

@@ -8,6 +8,7 @@
 
 class Adafruit_I2C :
 
+  @staticmethod
   def getPiRevision():
     "Gets the version number of the Raspberry Pi board"
     # Courtesy quick2wire-python-api
@@ -19,109 +20,110 @@ def getPiRevision():
             return 1 if line.rstrip()[-1] in ['1','2'] else 2
     except:
       return 0
+
+  @staticmethod
+  def getPiI2CBusNumber():
+    # Gets the I2C bus number /dev/i2c#
+    return 1 if Adafruit_I2C.getPiRevision() > 1 else 0
 
-  def __init__(self, address, bus=smbus.SMBus(1 if getPiRevision() > 1 else 0), debug=False):
+  def __init__(self, address, bus=-1, debug=False):
     self.address = address
-	# By default, the correct I2C bus is auto-detected using /proc/cpuinfo
-    self.bus = bus
-	# Alternatively, you can hard-code the bus version below:
-	# self.bus = smbus.SMBus(0); # Force I2C0 (early 256MB Pi's)
+    # By default, the correct I2C bus is auto-detected using /proc/cpuinfo
+    # Alternatively, you can hard-code the bus version below:
+    # self.bus = smbus.SMBus(0); # Force I2C0 (early 256MB Pi's)
     # self.bus = smbus.SMBus(1); # Force I2C1 (512MB Pi's)
+    self.bus = smbus.SMBus(
+      bus if bus >= 0 else Adafruit_I2C.getPiI2CBusNumber())
     self.debug = debug
 
   def reverseByteOrder(self, data):
     "Reverses the byte order of an int (16-bit) or long (32-bit) value"
     # Courtesy Vishal Sapre
-    dstr = hex(data)[2:].replace('L','')
-    byteCount = len(dstr[::2])
-    val = 0
-    for i, n in enumerate(range(byteCount)):
-      d = data & 0xFF
-      val |= (d << (8 * (byteCount - i - 1)))
+    byteCount = len(hex(data)[2:].replace('L','')[::2])
+    val       = 0
+    for i in range(byteCount):
+      val    = (val << 8) | (data & 0xff)
       data >>= 8
     return val
 
+  def errMsg():
+    print "Error accessing 0x%02X: Check your I2C address" % self.address
+    return -1
+
   def write8(self, reg, value):
     "Writes an 8-bit value to the specified register/address"
     try:
       self.bus.write_byte_data(self.address, reg, value)
-      if (self.debug):
+      if self.debug:
         print "I2C: Wrote 0x%02X to register 0x%02X" % (value, reg)
     except IOError, err:
-      print "Error accessing 0x%02X: Check your I2C address" % self.address
-      return -1
+      return errMsg()
 
   def writeList(self, reg, list):
     "Writes an array of bytes using I2C format"
     try:
-      if (self.debug):
+      if self.debug:
         print "I2C: Writing list to register 0x%02X:" % reg
         print list
       self.bus.write_i2c_block_data(self.address, reg, list)
     except IOError, err:
-      print "Error accessing 0x%02X: Check your I2C address" % self.address
-      return -1
+      return errMsg()
 
   def readList(self, reg, length):
     "Read a list of bytes from the I2C device"
     results = []
     try:
       results = self.bus.read_i2c_block_data(self.address, reg, length)
-      if (self.debug):
-        print "I2C: Device 0x%02X returned the following from reg 0x%02X" % (self.address, reg)
+      if self.debug:
+        print ("I2C: Device 0x%02X returned the following from reg 0x%02X" %
+         (self.address, reg))
         print results
       return results
     except IOError, err:
-      print "Error accessing 0x%02X: Check your I2C address" % self.address
-      return -1
+      return errMsg()
 
   def readU8(self, reg):
     "Read an unsigned byte from the I2C device"
     try:
       result = self.bus.read_byte_data(self.address, reg)
-      if (self.debug):
-        print "I2C: Device 0x%02X returned 0x%02X from reg 0x%02X" % (self.address, result & 0xFF, reg)
+      if self.debug:
+        print ("I2C: Device 0x%02X returned 0x%02X from reg 0x%02X" %
+         (self.address, result & 0xFF, reg))
       return result
     except IOError, err:
-      print "Error accessing 0x%02X: Check your I2C address" % self.address
-      return -1
+      return errMsg()
 
   def readS8(self, reg):
     "Reads a signed byte from the I2C device"
     try:
       result = self.bus.read_byte_data(self.address, reg)
-      if (self.debug):
-        print "I2C: Device 0x%02X returned 0x%02X from reg 0x%02X" % (self.address, result & 0xFF, reg)
-      if (result > 127):
-        return result - 256
-      else:
-        return result
+      if result > 127: result -= 256
+      if self.debug:
+        print ("I2C: Device 0x%02X returned 0x%02X from reg 0x%02X" %
+         (self.address, result & 0xFF, reg))
+      return result
     except IOError, err:
-      print "Error accessing 0x%02X: Check your I2C address" % self.address
-      return -1
+      return errMsg()
 
   def readU16(self, reg):
     "Reads an unsigned 16-bit value from the I2C device"
     try:
-      hibyte = self.bus.read_byte_data(self.address, reg)
-      result = (hibyte << 8) + self.bus.read_byte_data(self.address, reg+1)
-      if (self.debug):
-        print "I2C: Device 0x%02X returned 0x%04X from reg 0x%02X" % (self.address, result & 0xFFFF, reg)
+      result = self.bus.read_word_data(self.address, reg)
+      if self.debug:
+        print ("I2C: Device 0x%02X returned 0x%04X from reg 0x%02X" %
+         (self.address, result & 0xFFFF, reg))
       return result
     except IOError, err:
-      print "Error accessing 0x%02X: Check your I2C address" % self.address
-      return -1
+      return errMsg()
 
   def readS16(self, reg):
     "Reads a signed 16-bit value from the I2C device"
     try:
-      hibyte = self.bus.read_byte_data(self.address, reg)
-      if (hibyte > 127):
-        hibyte -= 256
-      result = (hibyte << 8) + self.bus.read_byte_data(self.address, reg+1)
-      if (self.debug):
-        print "I2C: Device 0x%02X returned 0x%04X from reg 0x%02X" % (self.address, result & 0xFFFF, reg)
+      result = self.bus.read_word_data(self.address, reg)
+      if result > 32767: result -= 65536
+      if self.debug:
+        print ("I2C: Device 0x%02X returned 0x%04X from reg 0x%02X" %
+         (self.address, result & 0xFFFF, reg))
       return result
     except IOError, err:
-      print "Error accessing 0x%02X: Check your I2C address" % self.address
-      return -1
+      return errMsg()