Refactor platform_detect to Platform, add Pi revision detect function, and default I2C bus function.

Author: tdicola

Adafruit_GPIO/I2C.py

@@ -24,6 +24,8 @@
 
 import smbus
 
+import Adafruit_GPIO.Platform as Platform
+
 
 logger = logging.getLogger(__name__)
 
@@ -40,10 +42,22 @@ def reverseByteOrder(data):
 
 def get_default_bus():
 	"""Return the default bus number based on the device platform.  For a
-	Raspberry Pi either bus 0 or 1 (baed on the Pi revision) will be returned.
+	Raspberry Pi either bus 0 or 1 (based on the Pi revision) will be returned.
 	For a Beaglebone Black the first user accessible bus, 1, will be returned.
 	"""
-	return 0
+	plat = Platform.platform_detect()
+	if plat == Platform.RASPBERRY_PI:
+		if Platform.pi_revision() == 1:
+			# Revision 1 Pi uses I2C bus 0.
+			return 0
+		else:
+			# Revision 2 Pi uses I2C bus 1.
+			return 1
+	elif plat == Platform.BEAGLEBONE_BLACK:
+		# Beaglebone Black has multiple I2C buses, default to 1 (P9_19 and P9_20).
+		return 1
+	else:
+		raise RuntimeError('Could not determine default I2C bus for platform.')
 
 
 class Device(object):

Adafruit_GPIO/platform_detect.py Adafruit_GPIO/Platform.py

@@ -19,6 +19,7 @@
 # OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
 # SOFTWARE.
 import platform
+import re
 
 # Platform identification constants.
 UNKNOWN          = 0
@@ -47,4 +48,24 @@ def platform_detect():
 	elif plat.lower().find('armv7l-with-debian') > -1:
 		return BEAGLEBONE_BLACK
 	else:
-		return UNKNOWN
+		return UNKNOWN
+
+def pi_revision():
+	"""Detect the revision number of a Raspberry Pi, useful for changing
+	functionality like default I2C bus based on revision."""
+	# Revision list available at: http://elinux.org/RPi_HardwareHistory#Board_Revision_History
+	with open('/proc/cpuinfo', 'r') as infile:
+		for line in infile:
+			# Match a line of the form "Revision : 0002" while ignoring extra
+			# info in front of the revsion (like 1000 when the Pi was over-volted).
+			match = re.match('Revision\s+:\s+.*(\w{4})$', line)
+			if match and match.group(1) in ['0002', '0003']:
+				# Return revision 1 if revision ends with 0002 or 0003.
+				return 1
+			elif match:
+				# Assume revision 2 if revision ends with any other 4 chars.
+				return 2
+			else:
+				# Couldn't find the revision, throw an exception.
+				raise RuntimeError('Could not determine Raspberry Pi revision.')
+

test/test_GPIO.py

@@ -107,25 +107,18 @@ def test_input(self):
 
 
 class TestGetPlatformGPIO(unittest.TestCase):
+	@patch.dict('sys.modules', {'RPi': Mock(), 'RPi.GPIO': Mock()})
+	@patch('platform.platform', Mock(return_value='Linux-3.10.25+-armv6l-with-debian-7.4'))
 	def test_raspberrypi(self):
-		rpi = Mock()
-		with patch('platform.platform', 
-				   new=Mock(return_value='Linux-3.10.25+-armv6l-with-debian-7.4')):
-			with patch.dict('sys.modules', 
-							{'RPi': rpi, 'RPi.GPIO': rpi.gpio}):
-				gpio = GPIO.get_platform_gpio()
-				self.assertIsInstance(gpio, GPIO.RPiGPIOAdapter)
+		gpio = GPIO.get_platform_gpio()
+		self.assertIsInstance(gpio, GPIO.RPiGPIOAdapter)
 
+	@patch.dict('sys.modules', {'Adafruit_BBIO': Mock(), 'Adafruit_BBIO.GPIO': Mock()})
+	@patch('platform.platform', Mock(return_value='Linux-3.8.13-bone47-armv7l-with-debian-7.4'))
 	def test_beagleboneblack(self):
-		bbio = Mock()
-		with patch('platform.platform', 
-				   new=Mock(return_value='Linux-3.8.13-bone47-armv7l-with-debian-7.4')):
-			with patch.dict('sys.modules', 
-			 				{'Adafruit_BBIO': bbio, 'Adafruit_BBIO.GPIO': bbio.gpio}):
-				gpio = GPIO.get_platform_gpio()
-				self.assertIsInstance(gpio, GPIO.AdafruitBBIOAdapter)
+		gpio = GPIO.get_platform_gpio()
+		self.assertIsInstance(gpio, GPIO.AdafruitBBIOAdapter)
 
+	@patch('platform.platform', Mock(return_value='Darwin-13.2.0-x86_64-i386-64bit'))
 	def test_otherplatform(self):
-		with patch('platform.platform', 
-				   new=Mock(return_value='Darwin-13.2.0-x86_64-i386-64bit')):
-			self.assertRaises(RuntimeError, GPIO.get_platform_gpio)
+		self.assertRaises(RuntimeError, GPIO.get_platform_gpio)

test/test_I2C.py

@@ -24,6 +24,8 @@
 
 from mock import Mock, patch
 
+import Adafruit_GPIO.Platform as Platform
+
 
 # Enable debug logging to stdout during tests.
 logging.basicConfig()
@@ -70,15 +72,23 @@ def read_i2c_block_data(self, address, length):
 
 
 def create_device(address, busnum):
-		# Mock the smbus module and inject it into the global namespace so the
-		# Adafruit_GPIO.I2C module can be imported.  Also inject a mock SMBus
-		# instance to be returned by smbus.SMBus function calls.
-		smbus = Mock()
-		mockbus = MockSMBus()
-		smbus.SMBus.return_value = mockbus
-		with patch.dict('sys.modules', {'smbus': smbus}):
-			import Adafruit_GPIO.I2C as I2C
-			return (I2C.Device(address, busnum), smbus, mockbus)
+	# Mock the smbus module and inject it into the global namespace so the
+	# Adafruit_GPIO.I2C module can be imported.  Also inject a mock SMBus
+	# instance to be returned by smbus.SMBus function calls.
+	smbus = Mock()
+	mockbus = MockSMBus()
+	smbus.SMBus.return_value = mockbus
+	with patch.dict('sys.modules', {'smbus': smbus}):
+		import Adafruit_GPIO.I2C as I2C
+		return (I2C.Device(address, busnum), smbus, mockbus)
+
+def safe_import_i2c():
+	# Mock the smbus module and inject it into the global namespace so the
+	# Adafruit_GPIO.I2C module can be imported.  The imported I2C module is
+	# returned so global functions can be called on it.
+	with patch.dict('sys.modules', {'smbus': Mock() }):
+		import Adafruit_GPIO.I2C as I2C
+		return I2C
 
 
 class TestI2CDevice(unittest.TestCase):
@@ -144,3 +154,28 @@ def test_readS16(self):
 		self.assertEqual(value, -4863)
 
 
+class TestGetDefaultBus(unittest.TestCase):
+	@patch('Adafruit_GPIO.Platform.pi_revision', Mock(return_value=1))
+	@patch('Adafruit_GPIO.Platform.platform_detect', Mock(return_value=Platform.RASPBERRY_PI))
+	def test_raspberry_pi_rev1(self):
+		I2C = safe_import_i2c()
+		bus = I2C.get_default_bus()
+		self.assertEqual(bus, 0)
+
+	@patch('Adafruit_GPIO.Platform.pi_revision', Mock(return_value=2))
+	@patch('Adafruit_GPIO.Platform.platform_detect', Mock(return_value=Platform.RASPBERRY_PI))
+	def test_raspberry_pi_rev2(self):
+		I2C = safe_import_i2c()
+		bus = I2C.get_default_bus()
+		self.assertEqual(bus, 1)
+
+	@patch('Adafruit_GPIO.Platform.platform_detect', Mock(return_value=Platform.BEAGLEBONE_BLACK))
+	def test_beaglebone_black(self):
+		I2C = safe_import_i2c()
+		bus = I2C.get_default_bus()
+		self.assertEqual(bus, 1)
+
+	@patch('Adafruit_GPIO.Platform.platform_detect', Mock(return_value=Platform.UNKNOWN))
+	def test_unknown(self):
+		I2C = safe_import_i2c()
+		self.assertRaises(RuntimeError, I2C.get_default_bus)

test/test_Platform.py

@@ -0,0 +1,70 @@
+# Copyright (c) 2014 Adafruit Industries
+# Author: Tony DiCola
+#
+# Permission is hereby granted, free of charge, to any person obtaining a copy
+# of this software and associated documentation files (the "Software"), to deal
+# in the Software without restriction, including without limitation the rights
+# to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
+# copies of the Software, and to permit persons to whom the Software is
+# furnished to do so, subject to the following conditions:
+#
+# The above copyright notice and this permission notice shall be included in
+# all copies or substantial portions of the Software.
+#
+# THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+# IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+# FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
+# AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+# LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
+# OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
+# THE SOFTWARE.
+import unittest
+
+from mock import Mock, patch
+
+import Adafruit_GPIO.Platform as Platform
+
+
+class TestPlatformDetect(unittest.TestCase):
+	@patch('platform.platform', Mock(return_value='Linux-3.10.25+-armv6l-with-debian-7.4'))
+	def test_raspberry_pi(self):
+		result = Platform.platform_detect()
+		self.assertEquals(result, Platform.RASPBERRY_PI)
+
+	@patch('platform.platform', Mock(return_value='Linux-3.8.13-bone47-armv7l-with-debian-7.4'))
+	def test_beaglebone_black(self):
+		result = Platform.platform_detect()
+		self.assertEquals(result, Platform.BEAGLEBONE_BLACK)
+
+	@patch('platform.platform', Mock(return_value='Darwin-13.2.0-x86_64-i386-64bit'))
+	def test_unknown(self):
+		result = Platform.platform_detect()
+		self.assertEquals(result, Platform.UNKNOWN)
+
+
+class TestPiRevision(unittest.TestCase):
+	def test_revision_1(self):
+		with patch('__builtin__.open') as mock_open:
+			handle = mock_open.return_value.__enter__.return_value
+			handle.__iter__.return_value = iter(['Revision : 0002'])
+			rev = Platform.pi_revision()
+			self.assertEquals(rev, 1)
+		with patch('__builtin__.open') as mock_open:
+			handle = mock_open.return_value.__enter__.return_value
+			handle.__iter__.return_value = iter(['Revision : 0003'])
+			rev = Platform.pi_revision()
+			self.assertEquals(rev, 1)
+
+	def test_revision_2(self):
+		with patch('__builtin__.open') as mock_open:
+			handle = mock_open.return_value.__enter__.return_value
+			handle.__iter__.return_value = iter(['Revision : 000e'])
+			rev = Platform.pi_revision()
+			self.assertEquals(rev, 2)
+
+	def test_unknown_revision(self):
+		with patch('__builtin__.open') as mock_open:
+			handle = mock_open.return_value.__enter__.return_value
+			handle.__iter__.return_value = iter(['foobar'])
+			self.assertRaises(RuntimeError, Platform.pi_revision)
+