Encoder: added sysfs module

Author: dplanella

Adafruit_BBIO/sysfs.py

@@ -0,0 +1,116 @@
+#!/usr/bin/python
+# -*- coding: utf-8 -*-
+
+# Copyright (c) 2014 MIT OpenCourseWare
+#
+# 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.
+#
+# Code originally published at http://stackoverflow.com/questions/4648792/ and
+# subsequently forked at https://github.com/ponycloud/python-sysfs
+#
+# Original author: Benedikt Reinartz <filmor@gmail.com>
+# Contributors:
+#     - Jan Dvořák <mordae@anilinux.org>
+#     - Jonathon Reinhart https://github.com/JonathonReinhart
+#     - Ondřej Koch <o.koch@zerusnet.com>
+#     - David Planella <david.planella@ubuntu.com>
+
+"""
+Simplistic Python SysFS interface.
+
+Usage examples::
+    from sysfs import sys
+
+    # Print all block devices in /sys, with their sizes
+    for block_dev in sys.block:
+        print block_dev, str(int(block_dev.size) / 1048576) + ' M'
+
+    >>> import sysfs
+    >>> # Read/write Beaglebone Black's eQEP module attributes
+    >>> eqep0 = sysfs.Node("/sys/devices/platform/ocp/48300000.epwmss/48300180.eqep")
+    >>> # Read eqep attributes
+    >>> eqep0.enabled
+    '1'
+    >>> eqep0.mode
+    '0'
+    >>> eqep0.period
+    '1000000000'
+    >>> eqep0.position
+    '0'
+    >>> # Write eqep attributes. They should be strings.
+    >>> eqep0.position = str(2)
+    >>> eqep0.position
+    '2'
+"""
+
+from os import listdir
+from os.path import isdir, isfile, join, realpath, basename
+
+__all__ = ['sys', 'Node']
+
+
+class Node(object):
+    __slots__ = ['_path_', '__dict__']
+
+    def __init__(self, path='/sys'):
+        self._path_ = realpath(path)
+        if not self._path_.startswith('/sys/') and not '/sys' == self._path_:
+            raise RuntimeError('Using this on non-sysfs files is dangerous!')
+
+        self.__dict__.update(dict.fromkeys(listdir(self._path_)))
+
+    def __repr__(self):
+        return '<sysfs.Node "%s">' % self._path_
+
+    def __str__(self):
+        return basename(self._path_)
+
+    def __setattr__(self, name, val):
+        if name.startswith('_'):
+            return object.__setattr__(self, name, val)
+
+        path = realpath(join(self._path_, name))
+        if isfile(path):
+            with open(path, 'w') as fp:
+                fp.write(val)
+        else:
+            raise RuntimeError('Cannot write to non-files.')
+
+    def __getattribute__(self, name):
+        if name.startswith('_'):
+            return object.__getattribute__(self, name)
+
+        path = realpath(join(self._path_, name))
+        if isfile(path):
+            with open(path, 'r') as fp:
+                return fp.read().strip()
+        elif isdir(path):
+            return Node(path)
+
+    def __setitem__(self, name, val):
+        return setattr(self, name, val)
+
+    def __getitem__(self, name):
+        return getattr(self, name)
+
+    def __iter__(self):
+        return iter(getattr(self, name) for name in listdir(self._path_))
+
+
+sys = Node()