From a14ec51fde454f6bbab143b51c6f62822f2c025a Mon Sep 17 00:00:00 2001 From: Tony DiCola Date: Fri, 19 Feb 2016 09:41:53 +0000 Subject: [PATCH] Initial commit. --- Adafruit_PureIO/__init__.py | 0 Adafruit_PureIO/smbus.py | 295 ++++++++++++++++++++++++++++++++ LICENSE | 21 +++ README.md | 10 +- ez_setup.py | 332 ++++++++++++++++++++++++++++++++++++ setup.py | 21 +++ tests/test_I2C.py | 49 ++++++ 7 files changed, 726 insertions(+), 2 deletions(-) create mode 100644 Adafruit_PureIO/__init__.py create mode 100644 Adafruit_PureIO/smbus.py create mode 100644 LICENSE create mode 100644 ez_setup.py create mode 100644 setup.py create mode 100644 tests/test_I2C.py diff --git a/Adafruit_PureIO/__init__.py b/Adafruit_PureIO/__init__.py new file mode 100644 index 0000000..e69de29 diff --git a/Adafruit_PureIO/smbus.py b/Adafruit_PureIO/smbus.py new file mode 100644 index 0000000..cd3ba7d --- /dev/null +++ b/Adafruit_PureIO/smbus.py @@ -0,0 +1,295 @@ +# Copyright (c) 2016 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. +from ctypes import * +from fcntl import ioctl +import struct + +# I2C C API constants (from linux kernel headers) +I2C_M_TEN = 0x0010 # this is a ten bit chip address +I2C_M_RD = 0x0001 # read data, from slave to master +I2C_M_STOP = 0x8000 # if I2C_FUNC_PROTOCOL_MANGLING +I2C_M_NOSTART = 0x4000 # if I2C_FUNC_NOSTART +I2C_M_REV_DIR_ADDR = 0x2000 # if I2C_FUNC_PROTOCOL_MANGLING +I2C_M_IGNORE_NAK = 0x1000 # if I2C_FUNC_PROTOCOL_MANGLING +I2C_M_NO_RD_ACK = 0x0800 # if I2C_FUNC_PROTOCOL_MANGLING +I2C_M_RECV_LEN = 0x0400 # length will be first received byte + +I2C_SLAVE = 0x0703 # Use this slave address +I2C_SLAVE_FORCE = 0x0706 # Use this slave address, even if + # is already in use by a driver! +I2C_TENBIT = 0x0704 # 0 for 7 bit addrs, != 0 for 10 bit +I2C_FUNCS = 0x0705 # Get the adapter functionality mask +I2C_RDWR = 0x0707 # Combined R/W transfer (one STOP only) +I2C_PEC = 0x0708 # != 0 to use PEC with SMBus +I2C_SMBUS = 0x0720 # SMBus transfer + + +# ctypes versions of I2C structs defined by kernel. +class i2c_msg(Structure): + _fields_ = [ + ('addr', c_uint16), + ('flags', c_uint16), + ('len', c_uint16), + ('buf', POINTER(c_uint8)) + ] + +class i2c_rdwr_ioctl_data(Structure): + _fields_ = [ + ('msgs', POINTER(i2c_msg)), + ('nmsgs', c_uint32) + ] + + +def make_i2c_rdwr_data(messages): + """Utility function to create and return an i2c_rdwr_ioctl_data structure + populated with a list of specified I2C messages. The messages parameter + should be a list of tuples which represent the individual I2C messages to + send in this transaction. Tuples should contain 4 elements: address value, + flags value, buffer length, ctypes c_uint8 pointer to buffer. + """ + # Create message array and populate with provided data. + msg_data_type = i2c_msg*len(messages) + msg_data = msg_data_type() + for i, m in enumerate(messages): + msg_data[i].addr = m[0] & 0x7F + msg_data[i].flags = m[1] + msg_data[i].len = m[2] + msg_data[i].buf = m[3] + # Now build the data structure. + data = i2c_rdwr_ioctl_data() + data.msgs = msg_data + data.nmsgs = len(messages) + return data + + +# Create an interface that mimics the Python SMBus API. +class SMBus(object): + """I2C interface that mimics the Python SMBus API but is implemented with + pure Python calls to ioctl and direct /dev/i2c device access. + """ + + def __init__(self, bus=None): + """Create a new smbus instance. Bus is an optional parameter that + specifies the I2C bus number to use, for example 1 would use device + /dev/i2c-1. If bus is not specified then the open function should be + called to open the bus. + """ + self._device = None + if bus is not None: + self.open(bus) + + def __del__(self): + """Clean up any resources used by the SMBus instance.""" + self.close() + + def __enter__(self): + """Context manager enter function.""" + # Just return this object so it can be used in a with statement, like + # with SMBus(1) as bus: + # # do stuff! + return self + + def __exit__(self, exc_type, exc_val, exc_tb): + """Context manager exit function, ensures resources are cleaned up.""" + self.close() + return False # Don't suppress exceptions. + + def open(self, bus): + """Open the smbus interface on the specified bus.""" + # Close the device if it's already open. + if self._device is not None: + self.close() + # Try to open the file for the specified bus. Must turn off buffering + # or else Python 3 fails (see: https://bugs.python.org/issue20074) + self._device = open('/dev/i2c-{0}'.format(bus), 'r+b', buffering=0) + # TODO: Catch IOError and throw a better error message that describes + # what's wrong (i.e. I2C may not be enabled or the bus doesn't exist). + + def close(self): + """Close the smbus connection. You cannot make any other function + calls on the bus unless open is called!""" + if self._device is not None: + self._device.close() + self._device = None + + def _select_device(self, addr): + """Set the address of the device to communicate with on the I2C bus.""" + ioctl(self._device.fileno(), I2C_SLAVE, addr & 0x7F) + + def read_byte(self, addr): + """Read a single byte from the specified device.""" + assert self._device is not None, 'Bus must be opened before operations are made against it!' + self._select_device(addr) + return ord(self._device.read(1)) + + def read_byte_data(self, addr, cmd): + """Read a single byte from the specified cmd register of the device.""" + assert self._device is not None, 'Bus must be opened before operations are made against it!' + # Build ctypes values to marshall between ioctl and Python. + reg = c_uint8(cmd) + result = c_uint8() + # Build ioctl request. + request = make_i2c_rdwr_data([ + (addr, 0, 1, pointer(reg)), # Write cmd register. + (addr, I2C_M_RD, 1, pointer(result)) # Read 1 byte as result. + ]) + # Make ioctl call and return result data. + ioctl(self._device.fileno(), I2C_RDWR, request) + return result.value + + def read_word_data(self, addr, cmd): + """Read a word (2 bytes) from the specified cmd register of the device. + Note that this will interpret data using the endianness of the processor + running Python (typically little endian)! + """ + assert self._device is not None, 'Bus must be opened before operations are made against it!' + # Build ctypes values to marshall between ioctl and Python. + reg = c_uint8(cmd) + result = c_uint16() + # Build ioctl request. + request = make_i2c_rdwr_data([ + (addr, 0, 1, pointer(reg)), # Write cmd register. + (addr, I2C_M_RD, 2, cast(pointer(result), POINTER(c_uint8))) # Read word (2 bytes). + ]) + # Make ioctl call and return result data. + ioctl(self._device.fileno(), I2C_RDWR, request) + return result.value + + def read_block_data(self, addr, cmd): + """Perform a block read from the specified cmd register of the device. + The amount of data read is determined by the first byte send back by + the device. Data is returned as a bytearray. + """ + # TODO: Unfortunately this will require calling the low level I2C + # access ioctl to trigger a proper read_block_data. The amount of data + # returned isn't known until the device starts responding so an I2C_RDWR + # ioctl won't work. + raise NotImplementedError() + + def read_i2c_block_data(self, addr, cmd, len=32): + """Perform a read from the specified cmd register of device. Len number + of bytes (default of 32) will be read and returned as a bytearray. + """ + assert self._device is not None, 'Bus must be opened before operations are made against it!' + # Build ctypes values to marshall between ioctl and Python. + reg = c_uint8(cmd) + result = create_string_buffer(len) + # Build ioctl request. + request = make_i2c_rdwr_data([ + (addr, 0, 1, pointer(reg)), # Write cmd register. + (addr, I2C_M_RD, len, cast(pointer(result), POINTER(c_uint8))) # Read data. + ]) + # Make ioctl call and return result data. + ioctl(self._device.fileno(), I2C_RDWR, request) + return result.value + + def write_quick(self, addr): + """Write a single byte to the specified device.""" + # What a strange function, from the python-smbus source this appears to + # just write a single byte that initiates a write to the specified device + # address (but writes no data!). The functionality is duplicated below + # but the actual use case for this is unknown. + assert self._device is not None, 'Bus must be opened before operations are made against it!' + # Build ioctl request. + request = make_i2c_rdwr_data([ + (addr, 0, 0, None), # Write with no data. + ]) + # Make ioctl call and return result data. + ioctl(self._device.fileno(), I2C_RDWR, request) + + def write_byte(self, addr, val): + """Write a single byte to the specified device.""" + assert self._device is not None, 'Bus must be opened before operations are made against it!' + self._select_device(addr) + data = bytearray(1) + data[0] = val & 0xFF + self._device.write(data) + + def write_byte_data(self, addr, cmd, val): + """Write a byte of data to the specified cmd register of the device. + """ + assert self._device is not None, 'Bus must be opened before operations are made against it!' + # Construct a string of data to send with the command register and byte value. + data = bytearray(2) + data[0] = cmd & 0xFF + data[1] = val & 0xFF + # Send the data to the device. + self._select_device(addr) + self._device.write(data) + + def write_word_data(self, addr, cmd, val): + """Write a word (2 bytes) of data to the specified cmd register of the + device. Note that this will write the data in the endianness of the + processor running Python (typically little endian)! + """ + assert self._device is not None, 'Bus must be opened before operations are made against it!' + # Construct a string of data to send with the command register and word value. + data = struct.pack('=BH', cmd & 0xFF, val & 0xFFFF) + # Send the data to the device. + self._select_device(addr) + self._device.write(data) + + def write_block_data(self, addr, cmd, vals): + """Write a block of data to the specified cmd register of the device. + The amount of data to write should be the first byte inside the vals + string/bytearray and that count of bytes of data to write should follow + it. + """ + # Just use the I2C block data write to write the provided values and + # their length as the first byte. + data = bytearray(len(vals)+1) + data[0] = len(vals) & 0xFF + data[1:] = vals[0:] + self.write_i2c_block_data(addr, cmd, data) + + def write_i2c_block_data(self, addr, cmd, vals): + """Write a buffer of data to the specified cmd register of the device. + """ + assert self._device is not None, 'Bus must be opened before operations are made against it!' + assert vals is not None and len(vals) > 0, 'Vals must be a buffer with data!' + # Construct a string of data to send, including room for the command register. + data = bytearray(len(vals)+1) + data[0] = cmd & 0xFF # Command register at the start. + data[1:] = vals[0:] # Copy in the block data (ugly but necessary to ensure + # the entire write happens in one transaction). + # Send the data to the device. + self._select_device(addr) + self._device.write(data) + + def process_call(self, addr, cmd, val): + """Perform a smbus process call by writing a word (2 byte) value to + the specified register of the device, and then reading a word of response + data (which is returned). + """ + assert self._device is not None, 'Bus must be opened before operations are made against it!' + # Build ctypes values to marshall between ioctl and Python. + data = create_string_buffer(struct.pack('=BH', cmd, val)) + result = c_uint16() + # Build ioctl request. + request = make_i2c_rdwr_data([ + (addr, 0, 3, cast(pointer(data), POINTER(c_uint8))), # Write data. + (addr, I2C_M_RD, 2, cast(pointer(result), POINTER(c_uint8))) # Read word (2 bytes). + ]) + # Make ioctl call and return result data. + ioctl(self._device.fileno(), I2C_RDWR, request) + # Note the python-smbus code appears to have a rather serious bug and + # does not return the result value! This is fixed below by returning it. + return result.value diff --git a/LICENSE b/LICENSE new file mode 100644 index 0000000..d025531 --- /dev/null +++ b/LICENSE @@ -0,0 +1,21 @@ +The MIT License (MIT) + +Copyright (c) 2016 Adafruit Industries + +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. diff --git a/README.md b/README.md index 01dbedc..ad8e3af 100644 --- a/README.md +++ b/README.md @@ -1,2 +1,8 @@ -# Adafruit_Python_PureIO -Pure python (i.e. no native extensions) access to Linux IO including I2C and SPI. Drop in replacement for smbus and spidev modules. +# Adafruit Python PureIO + +Pure python (i.e. no native extensions) access to Linux IO including I2C and SPI. +Drop in replacement for smbus and spidev modules. + +NOTE: This is a work in progress that's not yet ready for public consumption. +API signatures could change and all APIs are not yet implemented. Wait for a +1.x.x series release before depending on this code. diff --git a/ez_setup.py b/ez_setup.py new file mode 100644 index 0000000..23ea9a2 --- /dev/null +++ b/ez_setup.py @@ -0,0 +1,332 @@ +#!/usr/bin/env python +"""Bootstrap setuptools installation + +To use setuptools in your package's setup.py, include this +file in the same directory and add this to the top of your setup.py:: + + from ez_setup import use_setuptools + use_setuptools() + +To require a specific version of setuptools, set a download +mirror, or use an alternate download directory, simply supply +the appropriate options to ``use_setuptools()``. + +This file can also be run as a script to install or upgrade setuptools. +""" +import os +import shutil +import sys +import tempfile +import zipfile +import optparse +import subprocess +import platform +import textwrap +import contextlib + +from distutils import log + +try: + from site import USER_SITE +except ImportError: + USER_SITE = None + +DEFAULT_VERSION = "3.5.1" +DEFAULT_URL = "https://pypi.python.org/packages/source/s/setuptools/" + +def _python_cmd(*args): + """ + Return True if the command succeeded. + """ + args = (sys.executable,) + args + return subprocess.call(args) == 0 + + +def _install(archive_filename, install_args=()): + with archive_context(archive_filename): + # installing + log.warn('Installing Setuptools') + if not _python_cmd('setup.py', 'install', *install_args): + log.warn('Something went wrong during the installation.') + log.warn('See the error message above.') + # exitcode will be 2 + return 2 + + +def _build_egg(egg, archive_filename, to_dir): + with archive_context(archive_filename): + # building an egg + log.warn('Building a Setuptools egg in %s', to_dir) + _python_cmd('setup.py', '-q', 'bdist_egg', '--dist-dir', to_dir) + # returning the result + log.warn(egg) + if not os.path.exists(egg): + raise IOError('Could not build the egg.') + + +def get_zip_class(): + """ + Supplement ZipFile class to support context manager for Python 2.6 + """ + class ContextualZipFile(zipfile.ZipFile): + def __enter__(self): + return self + def __exit__(self, type, value, traceback): + self.close + return zipfile.ZipFile if hasattr(zipfile.ZipFile, '__exit__') else \ + ContextualZipFile + + +@contextlib.contextmanager +def archive_context(filename): + # extracting the archive + tmpdir = tempfile.mkdtemp() + log.warn('Extracting in %s', tmpdir) + old_wd = os.getcwd() + try: + os.chdir(tmpdir) + with get_zip_class()(filename) as archive: + archive.extractall() + + # going in the directory + subdir = os.path.join(tmpdir, os.listdir(tmpdir)[0]) + os.chdir(subdir) + log.warn('Now working in %s', subdir) + yield + + finally: + os.chdir(old_wd) + shutil.rmtree(tmpdir) + + +def _do_download(version, download_base, to_dir, download_delay): + egg = os.path.join(to_dir, 'setuptools-%s-py%d.%d.egg' + % (version, sys.version_info[0], sys.version_info[1])) + if not os.path.exists(egg): + archive = download_setuptools(version, download_base, + to_dir, download_delay) + _build_egg(egg, archive, to_dir) + sys.path.insert(0, egg) + + # Remove previously-imported pkg_resources if present (see + # https://bitbucket.org/pypa/setuptools/pull-request/7/ for details). + if 'pkg_resources' in sys.modules: + del sys.modules['pkg_resources'] + + import setuptools + setuptools.bootstrap_install_from = egg + + +def use_setuptools(version=DEFAULT_VERSION, download_base=DEFAULT_URL, + to_dir=os.curdir, download_delay=15): + to_dir = os.path.abspath(to_dir) + rep_modules = 'pkg_resources', 'setuptools' + imported = set(sys.modules).intersection(rep_modules) + try: + import pkg_resources + except ImportError: + return _do_download(version, download_base, to_dir, download_delay) + try: + pkg_resources.require("setuptools>=" + version) + return + except pkg_resources.DistributionNotFound: + return _do_download(version, download_base, to_dir, download_delay) + except pkg_resources.VersionConflict as VC_err: + if imported: + msg = textwrap.dedent(""" + The required version of setuptools (>={version}) is not available, + and can't be installed while this script is running. Please + install a more recent version first, using + 'easy_install -U setuptools'. + + (Currently using {VC_err.args[0]!r}) + """).format(VC_err=VC_err, version=version) + sys.stderr.write(msg) + sys.exit(2) + + # otherwise, reload ok + del pkg_resources, sys.modules['pkg_resources'] + return _do_download(version, download_base, to_dir, download_delay) + +def _clean_check(cmd, target): + """ + Run the command to download target. If the command fails, clean up before + re-raising the error. + """ + try: + subprocess.check_call(cmd) + except subprocess.CalledProcessError: + if os.access(target, os.F_OK): + os.unlink(target) + raise + +def download_file_powershell(url, target): + """ + Download the file at url to target using Powershell (which will validate + trust). Raise an exception if the command cannot complete. + """ + target = os.path.abspath(target) + cmd = [ + 'powershell', + '-Command', + "(new-object System.Net.WebClient).DownloadFile(%(url)r, %(target)r)" % vars(), + ] + _clean_check(cmd, target) + +def has_powershell(): + if platform.system() != 'Windows': + return False + cmd = ['powershell', '-Command', 'echo test'] + devnull = open(os.path.devnull, 'wb') + try: + try: + subprocess.check_call(cmd, stdout=devnull, stderr=devnull) + except Exception: + return False + finally: + devnull.close() + return True + +download_file_powershell.viable = has_powershell + +def download_file_curl(url, target): + cmd = ['curl', url, '--silent', '--output', target] + _clean_check(cmd, target) + +def has_curl(): + cmd = ['curl', '--version'] + devnull = open(os.path.devnull, 'wb') + try: + try: + subprocess.check_call(cmd, stdout=devnull, stderr=devnull) + except Exception: + return False + finally: + devnull.close() + return True + +download_file_curl.viable = has_curl + +def download_file_wget(url, target): + cmd = ['wget', url, '--quiet', '--output-document', target] + _clean_check(cmd, target) + +def has_wget(): + cmd = ['wget', '--version'] + devnull = open(os.path.devnull, 'wb') + try: + try: + subprocess.check_call(cmd, stdout=devnull, stderr=devnull) + except Exception: + return False + finally: + devnull.close() + return True + +download_file_wget.viable = has_wget + +def download_file_insecure(url, target): + """ + Use Python to download the file, even though it cannot authenticate the + connection. + """ + try: + from urllib.request import urlopen + except ImportError: + from urllib2 import urlopen + src = dst = None + try: + src = urlopen(url) + # Read/write all in one block, so we don't create a corrupt file + # if the download is interrupted. + data = src.read() + dst = open(target, "wb") + dst.write(data) + finally: + if src: + src.close() + if dst: + dst.close() + +download_file_insecure.viable = lambda: True + +def get_best_downloader(): + downloaders = [ + download_file_powershell, + download_file_curl, + download_file_wget, + download_file_insecure, + ] + + for dl in downloaders: + if dl.viable(): + return dl + +def download_setuptools(version=DEFAULT_VERSION, download_base=DEFAULT_URL, + to_dir=os.curdir, delay=15, downloader_factory=get_best_downloader): + """ + Download setuptools from a specified location and return its filename + + `version` should be a valid setuptools version number that is available + as an egg for download under the `download_base` URL (which should end + with a '/'). `to_dir` is the directory where the egg will be downloaded. + `delay` is the number of seconds to pause before an actual download + attempt. + + ``downloader_factory`` should be a function taking no arguments and + returning a function for downloading a URL to a target. + """ + # making sure we use the absolute path + to_dir = os.path.abspath(to_dir) + zip_name = "setuptools-%s.zip" % version + url = download_base + zip_name + saveto = os.path.join(to_dir, zip_name) + if not os.path.exists(saveto): # Avoid repeated downloads + log.warn("Downloading %s", url) + downloader = downloader_factory() + downloader(url, saveto) + return os.path.realpath(saveto) + +def _build_install_args(options): + """ + Build the arguments to 'python setup.py install' on the setuptools package + """ + return ['--user'] if options.user_install else [] + +def _parse_args(): + """ + Parse the command line for options + """ + parser = optparse.OptionParser() + parser.add_option( + '--user', dest='user_install', action='store_true', default=False, + help='install in user site package (requires Python 2.6 or later)') + parser.add_option( + '--download-base', dest='download_base', metavar="URL", + default=DEFAULT_URL, + help='alternative URL from where to download the setuptools package') + parser.add_option( + '--insecure', dest='downloader_factory', action='store_const', + const=lambda: download_file_insecure, default=get_best_downloader, + help='Use internal, non-validating downloader' + ) + parser.add_option( + '--version', help="Specify which version to download", + default=DEFAULT_VERSION, + ) + options, args = parser.parse_args() + # positional arguments are ignored + return options + +def main(): + """Install or upgrade setuptools and EasyInstall""" + options = _parse_args() + archive = download_setuptools( + version=options.version, + download_base=options.download_base, + downloader_factory=options.downloader_factory, + ) + return _install(archive, _build_install_args(options)) + +if __name__ == '__main__': + sys.exit(main()) diff --git a/setup.py b/setup.py new file mode 100644 index 0000000..e7561e8 --- /dev/null +++ b/setup.py @@ -0,0 +1,21 @@ +from ez_setup import use_setuptools +use_setuptools() +from setuptools import setup, find_packages + +classifiers = ['Development Status :: 4 - Beta', + 'Operating System :: POSIX :: Linux', + 'License :: OSI Approved :: MIT License', + 'Intended Audience :: Developers', + 'Programming Language :: Python :: 2.7', + 'Programming Language :: Python :: 3', + 'Topic :: Software Development', + 'Topic :: System :: Hardware'] + +setup(name = 'Adafruit_PureIO', + version = '0.0.1', + author = 'Tony DiCola', + author_email = 'tdicola@adafruit.com', + description = 'Pure python (i.e. no native extensions) access to Linux IO including I2C and SPI. Drop in replacement for smbus and spidev modules.', + license = 'MIT', + classifiers = classifiers, + packages = find_packages()) diff --git a/tests/test_I2C.py b/tests/test_I2C.py new file mode 100644 index 0000000..afae21d --- /dev/null +++ b/tests/test_I2C.py @@ -0,0 +1,49 @@ +# Basic smbus test. This is pretty ugly and meant to be run against a ADS1x15 +# and some output inspected by a Saleae logic analyzer. TODO: Refactor into +# something that can test without hardware? +import binascii + +import Adafruit_PureIO.smbus as smbus + + +DEVICE_ADDR = 0x48 +REGISTER = 0x01 + + +# Test open and close. +i2c = smbus.SMBus() +i2c.open(1) +val = i2c.read_byte(DEVICE_ADDR) +print('read_byte from 0x{0:0X}: 0x{1:0X}'.format(REGISTER, val)) +i2c.close() + +# Test initializer open. +i2c = smbus.SMBus(1) +val = i2c.read_byte(DEVICE_ADDR) +print('read_byte from 0x{0:0X}: 0x{1:0X}'.format(REGISTER, val)) +i2c.close() + +# Test various data reads. +with smbus.SMBus(1) as i2c: + val = i2c.read_byte(DEVICE_ADDR) + print('read_byte from 0x{0:0X}: 0x{1:0X}'.format(REGISTER, val)) + val = i2c.read_byte_data(DEVICE_ADDR, REGISTER) + print('read_byte_data from 0x{0:0X}: 0x{1:0X}'.format(REGISTER, val)) + val = i2c.read_word_data(DEVICE_ADDR, REGISTER) + print('read_word_data from 0x{0:0X}: 0x{1:04X}'.format(REGISTER, val)) + val = i2c.read_i2c_block_data(DEVICE_ADDR, REGISTER, 2) + print('read_i2c_block_data from 0x{0:0X}: 0x{1}'.format(REGISTER, binascii.hexlify(val))) + +# Test various data writes. +with smbus.SMBus(1) as i2c: + i2c.write_byte(DEVICE_ADDR, REGISTER) + i2c.write_byte_data(DEVICE_ADDR, REGISTER, 0x85) + i2c.write_word_data(DEVICE_ADDR, REGISTER, 0x8385) + i2c.write_i2c_block_data(DEVICE_ADDR, REGISTER, [0x85, 0x83]) + #i2c.write_block_data(DEVICE_ADDR, REGISTER, [0x85, 0x83]) + i2c.write_quick(DEVICE_ADDR) + +# Process call test. +with smbus.SMBus(1) as i2c: + val = i2c.process_call(DEVICE_ADDR, REGISTER, 0x8385) + print('process_call from 0x{0:0X}: 0x{1:04X}'.format(REGISTER, val))