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
|
/* ir-rc5-decoder.c - handle RC5(x) IR Pulse/Space protocol
*
* Copyright (C) 2010 by Mauro Carvalho Chehab <mchehab@redhat.com>
*
* This program is free software; you can redistribute it and/or modify
* it under the terms of the GNU General Public License as published by
* the Free Software Foundation version 2 of the License.
*
* This program is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
* GNU General Public License for more details.
*/
/*
* This code handles 14 bits RC5 protocols and 20 bits RC5x protocols.
* There are other variants that use a different number of bits.
* This is currently unsupported.
* It considers a carrier of 36 kHz, with a total of 14/20 bits, where
* the first two bits are start bits, and a third one is a filing bit
*/
#include "ir-core-priv.h"
#define RC5_NBITS 14
#define RC5X_NBITS 20
#define CHECK_RC5X_NBITS 8
#define RC5_UNIT 888888 /* ns */
#define RC5_BIT_START (1 * RC5_UNIT)
#define RC5_BIT_END (1 * RC5_UNIT)
#define RC5X_SPACE (4 * RC5_UNIT)
enum rc5_state {
STATE_INACTIVE,
STATE_BIT_START,
STATE_BIT_END,
STATE_CHECK_RC5X,
STATE_FINISHED,
};
/**
* ir_rc5_decode() - Decode one RC-5 pulse or space
* @input_dev: the struct input_dev descriptor of the device
* @ev: the struct ir_raw_event descriptor of the pulse/space
*
* This function returns -EINVAL if the pulse violates the state machine
*/
static int ir_rc5_decode(struct input_dev *input_dev, struct ir_raw_event ev)
{
struct ir_input_dev *ir_dev = input_get_drvdata(input_dev);
struct rc5_dec *data = &ir_dev->raw->rc5;
u8 toggle;
u32 scancode;
if (!(ir_dev->raw->enabled_protocols & IR_TYPE_RC5))
return 0;
if (IS_RESET(ev)) {
data->state = STATE_INACTIVE;
return 0;
}
if (!geq_margin(ev.duration, RC5_UNIT, RC5_UNIT / 2))
goto out;
again:
IR_dprintk(2, "RC5(x) decode started at state %i (%uus %s)\n",
data->state, TO_US(ev.duration), TO_STR(ev.pulse));
if (!geq_margin(ev.duration, RC5_UNIT, RC5_UNIT / 2))
return 0;
switch (data->state) {
case STATE_INACTIVE:
if (!ev.pulse)
break;
data->state = STATE_BIT_START;
data->count = 1;
/* We just need enough bits to get to STATE_CHECK_RC5X */
data->wanted_bits = RC5X_NBITS;
decrease_duration(&ev, RC5_BIT_START);
goto again;
case STATE_BIT_START:
if (!eq_margin(ev.duration, RC5_BIT_START, RC5_UNIT / 2))
break;
data->bits <<= 1;
if (!ev.pulse)
data->bits |= 1;
data->count++;
data->state = STATE_BIT_END;
return 0;
case STATE_BIT_END:
if (!is_transition(&ev, &ir_dev->raw->prev_ev))
break;
if (data->count == data->wanted_bits)
data->state = STATE_FINISHED;
else if (data->count == CHECK_RC5X_NBITS)
data->state = STATE_CHECK_RC5X;
else
data->state = STATE_BIT_START;
decrease_duration(&ev, RC5_BIT_END);
goto again;
case STATE_CHECK_RC5X:
if (!ev.pulse && geq_margin(ev.duration, RC5X_SPACE, RC5_UNIT / 2)) {
/* RC5X */
data->wanted_bits = RC5X_NBITS;
decrease_duration(&ev, RC5X_SPACE);
} else {
/* RC5 */
data->wanted_bits = RC5_NBITS;
}
data->state = STATE_BIT_START;
goto again;
case STATE_FINISHED:
if (ev.pulse)
break;
if (data->wanted_bits == RC5X_NBITS) {
/* RC5X */
u8 xdata, command, system;
xdata = (data->bits & 0x0003F) >> 0;
command = (data->bits & 0x00FC0) >> 6;
system = (data->bits & 0x1F000) >> 12;
toggle = (data->bits & 0x20000) ? 1 : 0;
command += (data->bits & 0x01000) ? 0 : 0x40;
scancode = system << 16 | command << 8 | xdata;
IR_dprintk(1, "RC5X scancode 0x%06x (toggle: %u)\n",
scancode, toggle);
} else {
/* RC5 */
u8 command, system;
command = (data->bits & 0x0003F) >> 0;
system = (data->bits & 0x007C0) >> 6;
toggle = (data->bits & 0x00800) ? 1 : 0;
command += (data->bits & 0x01000) ? 0 : 0x40;
scancode = system << 8 | command;
IR_dprintk(1, "RC5 scancode 0x%04x (toggle: %u)\n",
scancode, toggle);
}
ir_keydown(input_dev, scancode, toggle);
data->state = STATE_INACTIVE;
return 0;
}
out:
IR_dprintk(1, "RC5(x) decode failed at state %i (%uus %s)\n",
data->state, TO_US(ev.duration), TO_STR(ev.pulse));
data->state = STATE_INACTIVE;
return -EINVAL;
}
static struct ir_raw_handler rc5_handler = {
.protocols = IR_TYPE_RC5,
.decode = ir_rc5_decode,
};
static int __init ir_rc5_decode_init(void)
{
ir_raw_handler_register(&rc5_handler);
printk(KERN_INFO "IR RC5(x) protocol handler initialized\n");
return 0;
}
static void __exit ir_rc5_decode_exit(void)
{
ir_raw_handler_unregister(&rc5_handler);
}
module_init(ir_rc5_decode_init);
module_exit(ir_rc5_decode_exit);
MODULE_LICENSE("GPL");
MODULE_AUTHOR("Mauro Carvalho Chehab <mchehab@redhat.com>");
MODULE_AUTHOR("Red Hat Inc. (http://www.redhat.com)");
MODULE_DESCRIPTION("RC5(x) IR protocol decoder");
|
