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
|
/* ir-sharp-decoder.c - handle Sharp IR Pulse/Space protocol
*
* Copyright (C) 2013-2014 Imagination Technologies Ltd.
*
* Based on NEC decoder:
* Copyright (C) 2010 by Mauro Carvalho Chehab
*
* 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.
*/
#include <linux/bitrev.h>
#include <linux/module.h>
#include "rc-core-priv.h"
#define SHARP_NBITS 15
#define SHARP_UNIT 40000 /* ns */
#define SHARP_BIT_PULSE (8 * SHARP_UNIT) /* 320us */
#define SHARP_BIT_0_PERIOD (25 * SHARP_UNIT) /* 1ms (680us space) */
#define SHARP_BIT_1_PERIOD (50 * SHARP_UNIT) /* 2ms (1680ms space) */
#define SHARP_ECHO_SPACE (1000 * SHARP_UNIT) /* 40 ms */
#define SHARP_TRAILER_SPACE (125 * SHARP_UNIT) /* 5 ms (even longer) */
enum sharp_state {
STATE_INACTIVE,
STATE_BIT_PULSE,
STATE_BIT_SPACE,
STATE_TRAILER_PULSE,
STATE_ECHO_SPACE,
STATE_TRAILER_SPACE,
};
/**
* ir_sharp_decode() - Decode one Sharp pulse or space
* @dev: the struct rc_dev descriptor of the device
* @duration: the struct ir_raw_event descriptor of the pulse/space
*
* This function returns -EINVAL if the pulse violates the state machine
*/
static int ir_sharp_decode(struct rc_dev *dev, struct ir_raw_event ev)
{
struct sharp_dec *data = &dev->raw->sharp;
u32 msg, echo, address, command, scancode;
if (!rc_protocols_enabled(dev, RC_BIT_SHARP))
return 0;
if (!is_timing_event(ev)) {
if (ev.reset)
data->state = STATE_INACTIVE;
return 0;
}
IR_dprintk(2, "Sharp decode started at state %d (%uus %s)\n",
data->state, TO_US(ev.duration), TO_STR(ev.pulse));
switch (data->state) {
case STATE_INACTIVE:
if (!ev.pulse)
break;
if (!eq_margin(ev.duration, SHARP_BIT_PULSE,
SHARP_BIT_PULSE / 2))
break;
data->count = 0;
data->pulse_len = ev.duration;
data->state = STATE_BIT_SPACE;
return 0;
case STATE_BIT_PULSE:
if (!ev.pulse)
break;
if (!eq_margin(ev.duration, SHARP_BIT_PULSE,
SHARP_BIT_PULSE / 2))
break;
data->pulse_len = ev.duration;
data->state = STATE_BIT_SPACE;
return 0;
case STATE_BIT_SPACE:
if (ev.pulse)
break;
data->bits <<= 1;
if (eq_margin(data->pulse_len + ev.duration, SHARP_BIT_1_PERIOD,
SHARP_BIT_PULSE * 2))
data->bits |= 1;
else if (!eq_margin(data->pulse_len + ev.duration,
SHARP_BIT_0_PERIOD, SHARP_BIT_PULSE * 2))
break;
data->count++;
if (data->count == SHARP_NBITS ||
data->count == SHARP_NBITS * 2)
data->state = STATE_TRAILER_PULSE;
else
data->state = STATE_BIT_PULSE;
return 0;
case STATE_TRAILER_PULSE:
if (!ev.pulse)
break;
if (!eq_margin(ev.duration, SHARP_BIT_PULSE,
SHARP_BIT_PULSE / 2))
break;
if (data->count == SHARP_NBITS) {
/* exp,chk bits should be 1,0 */
if ((data->bits & 0x3) != 0x2)
break;
data->state = STATE_ECHO_SPACE;
} else {
data->state = STATE_TRAILER_SPACE;
}
return 0;
case STATE_ECHO_SPACE:
if (ev.pulse)
break;
if (!eq_margin(ev.duration, SHARP_ECHO_SPACE,
SHARP_ECHO_SPACE / 4))
break;
data->state = STATE_BIT_PULSE;
return 0;
case STATE_TRAILER_SPACE:
if (ev.pulse)
break;
if (!geq_margin(ev.duration, SHARP_TRAILER_SPACE,
SHARP_BIT_PULSE / 2))
break;
/* Validate - command, ext, chk should be inverted in 2nd */
msg = (data->bits >> 15) & 0x7fff;
echo = data->bits & 0x7fff;
if ((msg ^ echo) != 0x3ff) {
IR_dprintk(1,
"Sharp checksum error: received 0x%04x, 0x%04x\n",
msg, echo);
break;
}
address = bitrev8((msg >> 7) & 0xf8);
command = bitrev8((msg >> 2) & 0xff);
scancode = address << 8 | command;
IR_dprintk(1, "Sharp scancode 0x%04x\n", scancode);
rc_keydown(dev, scancode, 0);
data->state = STATE_INACTIVE;
return 0;
}
IR_dprintk(1, "Sharp decode failed at count %d state %d (%uus %s)\n",
data->count, data->state, TO_US(ev.duration),
TO_STR(ev.pulse));
data->state = STATE_INACTIVE;
return -EINVAL;
}
static struct ir_raw_handler sharp_handler = {
.protocols = RC_BIT_SHARP,
.decode = ir_sharp_decode,
};
static int __init ir_sharp_decode_init(void)
{
ir_raw_handler_register(&sharp_handler);
pr_info("IR Sharp protocol handler initialized\n");
return 0;
}
static void __exit ir_sharp_decode_exit(void)
{
ir_raw_handler_unregister(&sharp_handler);
}
module_init(ir_sharp_decode_init);
module_exit(ir_sharp_decode_exit);
MODULE_LICENSE("GPL");
MODULE_AUTHOR("James Hogan <james.hogan@imgtec.com>");
MODULE_DESCRIPTION("Sharp IR protocol decoder");
|
