1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
|
import os
import os.path
class LEDError(IOError):
"""Base class for LED errors."""
pass
class LED(object):
def __init__(self, name, brightness=None):
"""Instantiate an LED object and open the sysfs LED corresponding to
the specified name.
`brightness` can be a boolean for on/off, integer value for a specific
brightness, or None to preserve existing brightness. Default is
preserve existing brightness.
Args:
name (str): Linux led name.
brightness (bool, int, None): Initial brightness.
Returns:
LED: LED object.
Raises:
LEDError: if an I/O or OS error occurs.
TypeError: if `name` or `brightness` types are invalid.
LookupError: if LED name does not exist.
ValueError: if `brightness` value is invalid.
"""
self._path = None
self._fd = None
self._name = None
self._max_brightness = None
self._open(name, brightness)
def __del__(self):
self.close()
def __enter__(self):
return self
def __exit__(self, t, value, traceback):
self.close()
def _open(self, name, brightness):
if not isinstance(name, str):
raise TypeError("Invalid name type, should be string.")
if not isinstance(brightness, (bool, int, type(None))):
raise TypeError("Invalid brightness type, should be bool, int, or None.")
led_path = "/sys/class/leds/{:s}".format(name)
if not os.path.isdir(led_path):
raise LookupError("Opening LED: LED \"{:s}\" not found.".format(name))
# Read max brightness
try:
with open(os.path.join(led_path, "max_brightness"), "r") as f_max_brightness:
self._max_brightness = int(f_max_brightness.read())
except IOError as e:
raise LEDError(e.errno, "Reading LED max brightness: " + e.strerror)
# Open brightness
try:
self._fd = os.open(os.path.join(led_path, "brightness"), os.O_RDWR)
except OSError as e:
raise LEDError(e.errno, "Opening LED brightness: " + e.strerror)
self._name = name
self._path = led_path
# Set initial brightness
if brightness:
self.write(brightness)
# Methods
def read(self):
"""Read the brightness of the LED.
Returns:
int: Current brightness.
Raises:
LEDError: if an I/O or OS error occurs.
"""
# Read value
try:
buf = os.read(self._fd, 8)
except OSError as e:
raise LEDError(e.errno, "Reading LED brightness: " + e.strerror)
# Rewind
try:
os.lseek(self._fd, 0, os.SEEK_SET)
except OSError as e:
raise LEDError(e.errno, "Rewinding LED brightness: " + e.strerror)
return int(buf)
def write(self, brightness):
"""Set the brightness of the LED to `brightness`.
`brightness` can be a boolean for on/off, or integer value for a
specific brightness.
Args:
brightness (bool, int): Brightness value to set.
Raises:
LEDError: if an I/O or OS error occurs.
TypeError: if `brightness` type is not bool or int.
"""
if not isinstance(brightness, (bool, int)):
raise TypeError("Invalid brightness type, should be bool or int.")
if isinstance(brightness, bool):
brightness = self._max_brightness if brightness else 0
else:
if not 0 <= brightness <= self._max_brightness:
raise ValueError("Invalid brightness value: should be between 0 and {:d}".format(self._max_brightness))
# Write value
try:
os.write(self._fd, "{:d}\n".format(brightness).encode())
except OSError as e:
raise LEDError(e.errno, "Writing LED brightness: " + e.strerror)
# Rewind
try:
os.lseek(self._fd, 0, os.SEEK_SET)
except OSError as e:
raise LEDError(e.errno, "Rewinding LED brightness: " + e.strerror)
def close(self):
"""Close the sysfs LED.
Raises:
LEDError: if an I/O or OS error occurs.
"""
if self._fd is None:
return
try:
os.close(self._fd)
except OSError as e:
raise LEDError(e.errno, "Closing LED: " + e.strerror)
self._fd = None
# Immutable properties
@property
def devpath(self):
"""Get the device path of the underlying sysfs LED device.
:type: str
"""
return self._path
@property
def fd(self):
"""Get the file descriptor for the underlying sysfs LED "brightness"
file of the LED object.
:type: int
"""
return self._fd
@property
def name(self):
"""Get the sysfs LED name.
:type: str
"""
return self._name
@property
def max_brightness(self):
"""Get the LED's max brightness.
:type: int
"""
return self._max_brightness
# Mutable properties
def _get_brightness(self):
# Read brightness
return self.read()
def _set_brightness(self, brightness):
return self.write(brightness)
brightness = property(_get_brightness, _set_brightness)
"""Get or set the LED's brightness.
Value can be a boolean for on/off, or integer value a for specific
brightness.
Raises:
LEDError: if an I/O or OS error occurs.
TypeError: if `brightness` type is not bool or int.
ValueError: if `brightness` value is invalid.
:type: int
"""
# String representation
def __str__(self):
return "LED {:s} (device={:s}, fd={:d}, max_brightness={:d})".format(self._name, self._path, self._fd, self._max_brightness)
|
