-
Notifications
You must be signed in to change notification settings - Fork 5
/
SMBus.pm
303 lines (196 loc) · 5.89 KB
/
SMBus.pm
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
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
262
263
264
265
266
267
268
269
270
271
272
273
274
275
276
277
278
279
280
281
282
283
284
285
286
287
288
289
290
291
292
293
294
295
296
297
298
299
300
301
302
303
use strict;
use warnings;
package Device::SMBus;
# PODNAME: Device::SMBus
# ABSTRACT: Perl interface for smbus using libi2c-dev library.
# COPYRIGHT
# VERSION
# Dependencies
use 5.010000;
use Moose;
use Carp;
use IO::File;
use Fcntl;
require XSLoader;
XSLoader::load('Device::SMBus', $VERSION);
=constant I2C_SLAVE
=cut
use constant I2C_SLAVE => 0x0703;
=attr I2CBusDevicePath
Device path of the I2C Device.
* On Raspberry Pi Model A this would usually be /dev/i2c-0 if you are using the default pins.
* On Raspberry Pi Model B this would usually be /dev/i2c-1 if you are using the default pins.
=cut
has I2CBusDevicePath => (
is => 'ro',
);
has I2CBusFileHandle => (
is => 'ro',
lazy => 1,
builder => '_build_I2CBusFileHandle',
);
=attr I2CDeviceAddress
This is the Address of the device on the I2C bus, this is usually available in the device Datasheet.
* for /dev/i2c-0 look at output of `sudo i2cdetect -y 0'
* for /dev/i2c-1 look at output of `sudo i2cdetect -y 1'
=cut
has I2CDeviceAddress => (
is => 'ro',
);
has I2CBusFilenumber => (
is => 'ro',
lazy => 1,
builder => '_build_I2CBusFilenumber',
);
sub _build_I2CBusFileHandle {
my ($self) = @_;
my $fh = IO::File->new( $self->I2CBusDevicePath, O_RDWR );
if( !$fh ){
croak "Unable to open I2C Device File at $self->I2CBusDevicePath";
return -1;
}
$fh->ioctl(I2C_SLAVE,$self->I2CDeviceAddress);
return $fh;
}
# Implicitly Call the lazy builder for the file handle by using it and get the filenumber
sub _build_I2CBusFilenumber {
my ($self) = @_;
$self->I2CBusFileHandle->fileno();
}
=method fileError
returns IO::Handle->error() for the device handle since the last clearerr
=cut
sub fileError {
my ($self) = @_;
return $self->I2CBusFileHandle->error();
}
=method writeQuick
$self->writeQuick($value)
=cut
sub writeQuick {
my ($self,$value) = @_;
my $retval = Device::SMBus::_writeQuick($self->I2CBusFilenumber,$value);
}
=method readByte
$self->readByte()
=cut
sub readByte {
my ($self) = @_;
my $retval = Device::SMBus::_readByte($self->I2CBusFilenumber);
}
=method writeByte
$self->writeByte()
=cut
sub writeByte {
my ($self, $value) = @_;
my $retval = Device::SMBus::_writeByte($self->I2CBusFilenumber,$value);
}
=method readByteData
$self->readByteData($register_address)
=cut
sub readByteData {
my ($self,$register_address) = @_;
my $retval = Device::SMBus::_readByteData($self->I2CBusFilenumber,$register_address);
}
=method writeByteData
$self->writeByteData($register_address,$value)
=cut
sub writeByteData {
my ($self,$register_address,$value) = @_;
my $retval = Device::SMBus::_writeByteData($self->I2CBusFilenumber,$register_address,$value);
}
=method readNBytes
$self->readNBytes($lowest_byte_address, $number_of_bytes);
Read together N bytes of Data in linear register order. i.e. to read from 0x28,0x29,0x2a
$self->readNBytes(0x28,3);
=cut
sub readNBytes {
my ($self,$reg,$numBytes) = @_;
my $retval = 0;
$retval = ($retval << 8) | $self->readByteData($reg+$numBytes - $_) for (1 .. $numBytes);
return $retval;
}
=method readWordData
$self->readWordData($register_address)
=cut
sub readWordData {
my ($self,$register_address) = @_;
my $retval = Device::SMBus::_readWordData($self->I2CBusFilenumber,$register_address);
}
=method writeWordData
$self->writeWordData($register_address,$value)
=cut
sub writeWordData {
my ($self,$register_address,$value) = @_;
my $retval = Device::SMBus::_writeWordData($self->I2CBusFilenumber,$register_address,$value);
}
=method processCall
$self->processCall($register_address,$value)
=cut
sub processCall {
my ($self,$register_address,$value) = @_;
my $retval = Device::SMBus::_processCall($self->I2CBusFilenumber,$register_address,$value);
}
=method writeBlockData
$self->writeBlockData($register_address, $values)
Writes a maximum of 32 bytes in a single block to the i2c device. The supplied $values should be
an array ref containing the bytes to be written.
The register address should be one that is at the beginning of a contiguous block of registers of equal lengh
to the array of values passed. Not adhering to this will almost certainly result in unexpected behaviour in
the device.
=cut
sub writeBlockData {
my ( $self, $register_address, $values ) = @_;
my $value = pack "C*", @{$values};
my $retval = Device::SMBus::_writeI2CBlockData($self->I2CBusFilenumber,$register_address, $value);
return $retval;
}
# Preloaded methods go here.
=method DEMOLISH
Destructor
=cut
sub DEMOLISH {
my ($self) = @_;
$self->I2CBusFileHandle->close();
}
1;
__END__
=begin wikidoc
= SYNOPSIS
use Device::SMBus;
$dev = Device::SMBus->new(
I2CBusDevicePath => '/dev/i2c-1',
I2CDeviceAddress => 0x1e,
);
print $dev->readByteData(0x20);
= DESCRIPTION
This is a perl interface to smbus interface using libi2c-dev library.
Prerequisites:
* sudo apt-get install libi2c-dev i2c-tools build-essential
If you are using Angstrom Linux use the following:
* opkg install i2c-tools
* opkg install i2c-tools-dev
Enabling the I2C on a Raspberry Pi:
You will need to comment out the driver from the blacklist. currently the
I2C driver isn't being loaded.
sudo vim /etc/modprobe.d/raspi-blacklist.conf
Replace this line
blacklist i2c-bcm2708
with this
#blacklist i2c-bcm2708
You now need to edit the modules conf file.
sudo vim /etc/modules
Add these two lines;
i2c-dev
i2c-bcm2708
Now run this command(replace 1 with 0 for older model Pi)
sudo i2cdetect -y 1
you should now see the addresses of the i2c devices connected to your i2c bus
= USAGE
* This module provides a simplified object oriented interface to the libi2c-dev library for accessing electronic peripherals connected on the I2C bus. It uses Moose.
= see ALSO
* [Moose]
* [IO::File]
* [Fcntl]
=end wikidoc
=cut