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David Härdeman784a4932010-04-08 20:04:40 -03001/* ir-rc6-decoder.c - A decoder for the RC6 IR protocol
2 *
3 * Copyright (C) 2010 by David Härdeman <david@hardeman.nu>
4 *
5 * This program is free software; you can redistribute it and/or modify
6 * it under the terms of the GNU General Public License as published by
7 * the Free Software Foundation version 2 of the License.
8 *
9 * This program is distributed in the hope that it will be useful,
10 * but WITHOUT ANY WARRANTY; without even the implied warranty of
11 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
12 * GNU General Public License for more details.
13 */
14
Mauro Carvalho Chehabf62de672010-11-09 23:09:57 -030015#include "rc-core-priv.h"
Paul Gortmaker7a707b82011-07-03 14:03:12 -040016#include <linux/module.h>
David Härdeman784a4932010-04-08 20:04:40 -030017
18/*
19 * This decoder currently supports:
20 * RC6-0-16 (standard toggle bit in header)
lawrence rustdb9bc662011-10-31 08:39:32 -030021 * RC6-6A-20 (no toggle bit)
David Härdeman784a4932010-04-08 20:04:40 -030022 * RC6-6A-24 (no toggle bit)
23 * RC6-6A-32 (MCE version with toggle bit in body)
24 */
25
lawrence rustdb9bc662011-10-31 08:39:32 -030026#define RC6_UNIT 444444 /* nanosecs */
David Härdeman784a4932010-04-08 20:04:40 -030027#define RC6_HEADER_NBITS 4 /* not including toggle bit */
28#define RC6_0_NBITS 16
lawrence rustdb9bc662011-10-31 08:39:32 -030029#define RC6_6A_32_NBITS 32
30#define RC6_6A_NBITS 128 /* Variable 8..128 */
David Härdemane40b1122010-04-15 18:46:00 -030031#define RC6_PREFIX_PULSE (6 * RC6_UNIT)
32#define RC6_PREFIX_SPACE (2 * RC6_UNIT)
33#define RC6_BIT_START (1 * RC6_UNIT)
34#define RC6_BIT_END (1 * RC6_UNIT)
35#define RC6_TOGGLE_START (2 * RC6_UNIT)
36#define RC6_TOGGLE_END (2 * RC6_UNIT)
lawrence rustdb9bc662011-10-31 08:39:32 -030037#define RC6_SUFFIX_SPACE (6 * RC6_UNIT)
David Härdeman784a4932010-04-08 20:04:40 -030038#define RC6_MODE_MASK 0x07 /* for the header bits */
39#define RC6_STARTBIT_MASK 0x08 /* for the header bits */
40#define RC6_6A_MCE_TOGGLE_MASK 0x8000 /* for the body bits */
lawrence rustdb9bc662011-10-31 08:39:32 -030041#define RC6_6A_LCC_MASK 0xffff0000 /* RC6-6A-32 long customer code mask */
42#define RC6_6A_MCE_CC 0x800f0000 /* MCE customer code */
43#ifndef CHAR_BIT
44#define CHAR_BIT 8 /* Normally in <limits.h> */
45#endif
David Härdeman784a4932010-04-08 20:04:40 -030046
David Härdeman784a4932010-04-08 20:04:40 -030047enum rc6_mode {
48 RC6_MODE_0,
49 RC6_MODE_6A,
50 RC6_MODE_UNKNOWN,
51};
52
53enum rc6_state {
54 STATE_INACTIVE,
55 STATE_PREFIX_SPACE,
56 STATE_HEADER_BIT_START,
57 STATE_HEADER_BIT_END,
58 STATE_TOGGLE_START,
59 STATE_TOGGLE_END,
60 STATE_BODY_BIT_START,
61 STATE_BODY_BIT_END,
62 STATE_FINISHED,
63};
64
David Härdemanc2163692010-06-13 17:29:36 -030065static enum rc6_mode rc6_mode(struct rc6_dec *data)
David Härdeman784a4932010-04-08 20:04:40 -030066{
David Härdeman784a4932010-04-08 20:04:40 -030067 switch (data->header & RC6_MODE_MASK) {
68 case 0:
69 return RC6_MODE_0;
70 case 6:
71 if (!data->toggle)
72 return RC6_MODE_6A;
73 /* fall through */
74 default:
75 return RC6_MODE_UNKNOWN;
76 }
77}
78
79/**
80 * ir_rc6_decode() - Decode one RC6 pulse or space
David Härdemand8b4b582010-10-29 16:08:23 -030081 * @dev: the struct rc_dev descriptor of the device
David Härdemane40b1122010-04-15 18:46:00 -030082 * @ev: the struct ir_raw_event descriptor of the pulse/space
David Härdeman784a4932010-04-08 20:04:40 -030083 *
84 * This function returns -EINVAL if the pulse violates the state machine
85 */
David Härdemand8b4b582010-10-29 16:08:23 -030086static int ir_rc6_decode(struct rc_dev *dev, struct ir_raw_event ev)
David Härdeman784a4932010-04-08 20:04:40 -030087{
David Härdemand8b4b582010-10-29 16:08:23 -030088 struct rc6_dec *data = &dev->raw->rc6;
David Härdeman784a4932010-04-08 20:04:40 -030089 u32 scancode;
90 u8 toggle;
Sean Young6d741bf2017-08-07 16:20:58 -040091 enum rc_proto protocol;
David Härdeman784a4932010-04-08 20:04:40 -030092
Maxim Levitsky46519182010-10-16 19:56:28 -030093 if (!is_timing_event(ev)) {
94 if (ev.reset)
95 data->state = STATE_INACTIVE;
David Härdeman784a4932010-04-08 20:04:40 -030096 return 0;
97 }
98
David Härdemane40b1122010-04-15 18:46:00 -030099 if (!geq_margin(ev.duration, RC6_UNIT, RC6_UNIT / 2))
David Härdeman784a4932010-04-08 20:04:40 -0300100 goto out;
101
102again:
David Härdemane40b1122010-04-15 18:46:00 -0300103 IR_dprintk(2, "RC6 decode started at state %i (%uus %s)\n",
104 data->state, TO_US(ev.duration), TO_STR(ev.pulse));
David Härdeman784a4932010-04-08 20:04:40 -0300105
David Härdemane40b1122010-04-15 18:46:00 -0300106 if (!geq_margin(ev.duration, RC6_UNIT, RC6_UNIT / 2))
David Härdeman784a4932010-04-08 20:04:40 -0300107 return 0;
108
109 switch (data->state) {
110
111 case STATE_INACTIVE:
David Härdemane40b1122010-04-15 18:46:00 -0300112 if (!ev.pulse)
113 break;
114
115 /* Note: larger margin on first pulse since each RC6_UNIT
116 is quite short and some hardware takes some time to
117 adjust to the signal */
118 if (!eq_margin(ev.duration, RC6_PREFIX_PULSE, RC6_UNIT))
119 break;
120
121 data->state = STATE_PREFIX_SPACE;
122 data->count = 0;
123 return 0;
David Härdeman784a4932010-04-08 20:04:40 -0300124
125 case STATE_PREFIX_SPACE:
David Härdemane40b1122010-04-15 18:46:00 -0300126 if (ev.pulse)
127 break;
128
129 if (!eq_margin(ev.duration, RC6_PREFIX_SPACE, RC6_UNIT / 2))
130 break;
131
132 data->state = STATE_HEADER_BIT_START;
lawrence rustdb9bc662011-10-31 08:39:32 -0300133 data->header = 0;
David Härdemane40b1122010-04-15 18:46:00 -0300134 return 0;
David Härdeman784a4932010-04-08 20:04:40 -0300135
136 case STATE_HEADER_BIT_START:
David Härdemane40b1122010-04-15 18:46:00 -0300137 if (!eq_margin(ev.duration, RC6_BIT_START, RC6_UNIT / 2))
138 break;
139
140 data->header <<= 1;
141 if (ev.pulse)
142 data->header |= 1;
143 data->count++;
David Härdemane40b1122010-04-15 18:46:00 -0300144 data->state = STATE_HEADER_BIT_END;
145 return 0;
David Härdeman784a4932010-04-08 20:04:40 -0300146
147 case STATE_HEADER_BIT_END:
David Härdemand8b4b582010-10-29 16:08:23 -0300148 if (!is_transition(&ev, &dev->raw->prev_ev))
David Härdemane40b1122010-04-15 18:46:00 -0300149 break;
David Härdeman784a4932010-04-08 20:04:40 -0300150
David Härdemane40b1122010-04-15 18:46:00 -0300151 if (data->count == RC6_HEADER_NBITS)
152 data->state = STATE_TOGGLE_START;
153 else
154 data->state = STATE_HEADER_BIT_START;
155
156 decrease_duration(&ev, RC6_BIT_END);
157 goto again;
David Härdeman784a4932010-04-08 20:04:40 -0300158
159 case STATE_TOGGLE_START:
David Härdemane40b1122010-04-15 18:46:00 -0300160 if (!eq_margin(ev.duration, RC6_TOGGLE_START, RC6_UNIT / 2))
161 break;
162
163 data->toggle = ev.pulse;
David Härdemane40b1122010-04-15 18:46:00 -0300164 data->state = STATE_TOGGLE_END;
165 return 0;
David Härdeman784a4932010-04-08 20:04:40 -0300166
167 case STATE_TOGGLE_END:
David Härdemand8b4b582010-10-29 16:08:23 -0300168 if (!is_transition(&ev, &dev->raw->prev_ev) ||
David Härdemane40b1122010-04-15 18:46:00 -0300169 !geq_margin(ev.duration, RC6_TOGGLE_END, RC6_UNIT / 2))
170 break;
David Härdeman784a4932010-04-08 20:04:40 -0300171
David Härdemane40b1122010-04-15 18:46:00 -0300172 if (!(data->header & RC6_STARTBIT_MASK)) {
173 IR_dprintk(1, "RC6 invalid start bit\n");
174 break;
David Härdeman784a4932010-04-08 20:04:40 -0300175 }
David Härdemane40b1122010-04-15 18:46:00 -0300176
177 data->state = STATE_BODY_BIT_START;
David Härdemane40b1122010-04-15 18:46:00 -0300178 decrease_duration(&ev, RC6_TOGGLE_END);
179 data->count = 0;
lawrence rustdb9bc662011-10-31 08:39:32 -0300180 data->body = 0;
David Härdemane40b1122010-04-15 18:46:00 -0300181
182 switch (rc6_mode(data)) {
183 case RC6_MODE_0:
184 data->wanted_bits = RC6_0_NBITS;
185 break;
186 case RC6_MODE_6A:
lawrence rustdb9bc662011-10-31 08:39:32 -0300187 data->wanted_bits = RC6_6A_NBITS;
David Härdemane40b1122010-04-15 18:46:00 -0300188 break;
189 default:
190 IR_dprintk(1, "RC6 unknown mode\n");
191 goto out;
192 }
193 goto again;
David Härdeman784a4932010-04-08 20:04:40 -0300194
195 case STATE_BODY_BIT_START:
lawrence rustdb9bc662011-10-31 08:39:32 -0300196 if (eq_margin(ev.duration, RC6_BIT_START, RC6_UNIT / 2)) {
197 /* Discard LSB's that won't fit in data->body */
198 if (data->count++ < CHAR_BIT * sizeof data->body) {
199 data->body <<= 1;
200 if (ev.pulse)
201 data->body |= 1;
202 }
203 data->state = STATE_BODY_BIT_END;
204 return 0;
205 } else if (RC6_MODE_6A == rc6_mode(data) && !ev.pulse &&
206 geq_margin(ev.duration, RC6_SUFFIX_SPACE, RC6_UNIT / 2)) {
207 data->state = STATE_FINISHED;
208 goto again;
209 }
210 break;
David Härdeman784a4932010-04-08 20:04:40 -0300211
212 case STATE_BODY_BIT_END:
David Härdemand8b4b582010-10-29 16:08:23 -0300213 if (!is_transition(&ev, &dev->raw->prev_ev))
David Härdemane40b1122010-04-15 18:46:00 -0300214 break;
David Härdeman784a4932010-04-08 20:04:40 -0300215
David Härdemane40b1122010-04-15 18:46:00 -0300216 if (data->count == data->wanted_bits)
217 data->state = STATE_FINISHED;
218 else
219 data->state = STATE_BODY_BIT_START;
220
221 decrease_duration(&ev, RC6_BIT_END);
222 goto again;
David Härdeman784a4932010-04-08 20:04:40 -0300223
224 case STATE_FINISHED:
David Härdemane40b1122010-04-15 18:46:00 -0300225 if (ev.pulse)
226 break;
227
David Härdeman784a4932010-04-08 20:04:40 -0300228 switch (rc6_mode(data)) {
229 case RC6_MODE_0:
lawrence rustdb9bc662011-10-31 08:39:32 -0300230 scancode = data->body;
David Härdeman784a4932010-04-08 20:04:40 -0300231 toggle = data->toggle;
Sean Young6d741bf2017-08-07 16:20:58 -0400232 protocol = RC_PROTO_RC6_0;
David Härdeman784a4932010-04-08 20:04:40 -0300233 IR_dprintk(1, "RC6(0) scancode 0x%04x (toggle: %u)\n",
234 scancode, toggle);
235 break;
David Härdeman120703f2014-04-03 20:31:30 -0300236
David Härdeman784a4932010-04-08 20:04:40 -0300237 case RC6_MODE_6A:
lawrence rustdb9bc662011-10-31 08:39:32 -0300238 if (data->count > CHAR_BIT * sizeof data->body) {
239 IR_dprintk(1, "RC6 too many (%u) data bits\n",
240 data->count);
241 goto out;
David Härdeman784a4932010-04-08 20:04:40 -0300242 }
243
lawrence rustdb9bc662011-10-31 08:39:32 -0300244 scancode = data->body;
David Härdeman120703f2014-04-03 20:31:30 -0300245 switch (data->count) {
246 case 20:
Sean Young6d741bf2017-08-07 16:20:58 -0400247 protocol = RC_PROTO_RC6_6A_20;
lawrence rustdb9bc662011-10-31 08:39:32 -0300248 toggle = 0;
David Härdeman120703f2014-04-03 20:31:30 -0300249 break;
250 case 24:
Sean Young6d741bf2017-08-07 16:20:58 -0400251 protocol = RC_PROTO_RC6_6A_24;
David Härdeman120703f2014-04-03 20:31:30 -0300252 toggle = 0;
253 break;
254 case 32:
255 if ((scancode & RC6_6A_LCC_MASK) == RC6_6A_MCE_CC) {
Sean Young6d741bf2017-08-07 16:20:58 -0400256 protocol = RC_PROTO_RC6_MCE;
David Härdeman120703f2014-04-03 20:31:30 -0300257 toggle = !!(scancode & RC6_6A_MCE_TOGGLE_MASK);
David Härdemand2a74582014-11-20 18:09:54 -0300258 scancode &= ~RC6_6A_MCE_TOGGLE_MASK;
David Härdeman120703f2014-04-03 20:31:30 -0300259 } else {
Sean Young6d741bf2017-08-07 16:20:58 -0400260 protocol = RC_PROTO_RC6_6A_32;
David Härdeman120703f2014-04-03 20:31:30 -0300261 toggle = 0;
262 }
263 break;
264 default:
265 IR_dprintk(1, "RC6(6A) unsupported length\n");
266 goto out;
lawrence rustdb9bc662011-10-31 08:39:32 -0300267 }
David Härdeman120703f2014-04-03 20:31:30 -0300268
269 IR_dprintk(1, "RC6(6A) proto 0x%04x, scancode 0x%08x (toggle: %u)\n",
270 protocol, scancode, toggle);
David Härdeman784a4932010-04-08 20:04:40 -0300271 break;
272 default:
273 IR_dprintk(1, "RC6 unknown mode\n");
274 goto out;
275 }
276
David Härdeman120703f2014-04-03 20:31:30 -0300277 rc_keydown(dev, protocol, scancode, toggle);
David Härdeman784a4932010-04-08 20:04:40 -0300278 data->state = STATE_INACTIVE;
279 return 0;
280 }
281
282out:
David Härdemane40b1122010-04-15 18:46:00 -0300283 IR_dprintk(1, "RC6 decode failed at state %i (%uus %s)\n",
284 data->state, TO_US(ev.duration), TO_STR(ev.pulse));
David Härdeman784a4932010-04-08 20:04:40 -0300285 data->state = STATE_INACTIVE;
286 return -EINVAL;
287}
288
Antti Seppälä9d974e42015-03-31 14:48:09 -0300289static const struct ir_raw_timings_manchester ir_rc6_timings[4] = {
290 {
Sean Youngddf9c1b2018-01-05 08:26:51 -0500291 .leader_pulse = RC6_PREFIX_PULSE,
292 .leader_space = RC6_PREFIX_SPACE,
Antti Seppälä9d974e42015-03-31 14:48:09 -0300293 .clock = RC6_UNIT,
294 .invert = 1,
295 },
296 {
297 .clock = RC6_UNIT * 2,
298 .invert = 1,
299 },
300 {
301 .clock = RC6_UNIT,
302 .invert = 1,
303 .trailer_space = RC6_SUFFIX_SPACE,
304 },
305};
306
307/**
308 * ir_rc6_encode() - Encode a scancode as a stream of raw events
309 *
310 * @protocol: protocol to encode
311 * @scancode: scancode to encode
312 * @events: array of raw ir events to write into
313 * @max: maximum size of @events
314 *
315 * Returns: The number of events written.
316 * -ENOBUFS if there isn't enough space in the array to fit the
317 * encoding. In this case all @max events will have been written.
318 * -EINVAL if the scancode is ambiguous or invalid.
319 */
Sean Young6d741bf2017-08-07 16:20:58 -0400320static int ir_rc6_encode(enum rc_proto protocol, u32 scancode,
Antti Seppälä9d974e42015-03-31 14:48:09 -0300321 struct ir_raw_event *events, unsigned int max)
322{
323 int ret;
324 struct ir_raw_event *e = events;
325
Sean Young6d741bf2017-08-07 16:20:58 -0400326 if (protocol == RC_PROTO_RC6_0) {
Antti Seppälä9d974e42015-03-31 14:48:09 -0300327 /* Modulate the header (Start Bit & Mode-0) */
328 ret = ir_raw_gen_manchester(&e, max - (e - events),
Sean Youngddf9c1b2018-01-05 08:26:51 -0500329 &ir_rc6_timings[0],
Sean Young80008dd2018-01-05 08:38:43 -0500330 RC6_HEADER_NBITS, (1 << 3));
Antti Seppälä9d974e42015-03-31 14:48:09 -0300331 if (ret < 0)
332 return ret;
333
334 /* Modulate Trailer Bit */
335 ret = ir_raw_gen_manchester(&e, max - (e - events),
Sean Youngddf9c1b2018-01-05 08:26:51 -0500336 &ir_rc6_timings[1], 1, 0);
Antti Seppälä9d974e42015-03-31 14:48:09 -0300337 if (ret < 0)
338 return ret;
339
340 /* Modulate rest of the data */
341 ret = ir_raw_gen_manchester(&e, max - (e - events),
Sean Youngddf9c1b2018-01-05 08:26:51 -0500342 &ir_rc6_timings[2], RC6_0_NBITS,
Antti Seppälä9d974e42015-03-31 14:48:09 -0300343 scancode);
344 if (ret < 0)
345 return ret;
346
347 } else {
348 int bits;
349
350 switch (protocol) {
Sean Young6d741bf2017-08-07 16:20:58 -0400351 case RC_PROTO_RC6_MCE:
352 case RC_PROTO_RC6_6A_32:
Antti Seppälä9d974e42015-03-31 14:48:09 -0300353 bits = 32;
354 break;
Sean Young6d741bf2017-08-07 16:20:58 -0400355 case RC_PROTO_RC6_6A_24:
Antti Seppälä9d974e42015-03-31 14:48:09 -0300356 bits = 24;
357 break;
Sean Young6d741bf2017-08-07 16:20:58 -0400358 case RC_PROTO_RC6_6A_20:
Antti Seppälä9d974e42015-03-31 14:48:09 -0300359 bits = 20;
360 break;
361 default:
362 return -EINVAL;
363 }
364
Antti Seppälä9d974e42015-03-31 14:48:09 -0300365 /* Modulate the header (Start Bit & Header-version 6 */
366 ret = ir_raw_gen_manchester(&e, max - (e - events),
Sean Youngddf9c1b2018-01-05 08:26:51 -0500367 &ir_rc6_timings[0],
Sean Young80008dd2018-01-05 08:38:43 -0500368 RC6_HEADER_NBITS, (1 << 3 | 6));
Antti Seppälä9d974e42015-03-31 14:48:09 -0300369 if (ret < 0)
370 return ret;
371
372 /* Modulate Trailer Bit */
373 ret = ir_raw_gen_manchester(&e, max - (e - events),
Sean Youngddf9c1b2018-01-05 08:26:51 -0500374 &ir_rc6_timings[1], 1, 0);
Antti Seppälä9d974e42015-03-31 14:48:09 -0300375 if (ret < 0)
376 return ret;
377
378 /* Modulate rest of the data */
379 ret = ir_raw_gen_manchester(&e, max - (e - events),
Sean Youngddf9c1b2018-01-05 08:26:51 -0500380 &ir_rc6_timings[2],
Antti Seppälä9d974e42015-03-31 14:48:09 -0300381 bits,
382 scancode);
383 if (ret < 0)
384 return ret;
385 }
386
387 return e - events;
388}
389
David Härdeman784a4932010-04-08 20:04:40 -0300390static struct ir_raw_handler rc6_handler = {
Sean Young6d741bf2017-08-07 16:20:58 -0400391 .protocols = RC_PROTO_BIT_RC6_0 | RC_PROTO_BIT_RC6_6A_20 |
392 RC_PROTO_BIT_RC6_6A_24 | RC_PROTO_BIT_RC6_6A_32 |
393 RC_PROTO_BIT_RC6_MCE,
David Härdeman784a4932010-04-08 20:04:40 -0300394 .decode = ir_rc6_decode,
Antti Seppälä9d974e42015-03-31 14:48:09 -0300395 .encode = ir_rc6_encode,
Sean Youngcdfaa012017-02-25 06:51:30 -0500396 .carrier = 36000,
David Härdeman784a4932010-04-08 20:04:40 -0300397};
398
399static int __init ir_rc6_decode_init(void)
400{
401 ir_raw_handler_register(&rc6_handler);
402
403 printk(KERN_INFO "IR RC6 protocol handler initialized\n");
404 return 0;
405}
406
407static void __exit ir_rc6_decode_exit(void)
408{
409 ir_raw_handler_unregister(&rc6_handler);
410}
411
412module_init(ir_rc6_decode_init);
413module_exit(ir_rc6_decode_exit);
414
415MODULE_LICENSE("GPL");
416MODULE_AUTHOR("David Härdeman <david@hardeman.nu>");
417MODULE_DESCRIPTION("RC6 IR protocol decoder");