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David Härdemanbf670f62010-04-15 18:46:05 -03001/* ir-jvc-decoder.c - handle JVC IR Pulse/Space 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
15#include <linux/bitrev.h>
Mauro Carvalho Chehabf62de672010-11-09 23:09:57 -030016#include "rc-core-priv.h"
David Härdemanbf670f62010-04-15 18:46:05 -030017
18#define JVC_NBITS 16 /* dev(8) + func(8) */
19#define JVC_UNIT 525000 /* ns */
20#define JVC_HEADER_PULSE (16 * JVC_UNIT) /* lack of header -> repeat */
21#define JVC_HEADER_SPACE (8 * JVC_UNIT)
22#define JVC_BIT_PULSE (1 * JVC_UNIT)
23#define JVC_BIT_0_SPACE (1 * JVC_UNIT)
24#define JVC_BIT_1_SPACE (3 * JVC_UNIT)
25#define JVC_TRAILER_PULSE (1 * JVC_UNIT)
26#define JVC_TRAILER_SPACE (35 * JVC_UNIT)
27
David Härdemanbf670f62010-04-15 18:46:05 -030028enum jvc_state {
29 STATE_INACTIVE,
30 STATE_HEADER_SPACE,
31 STATE_BIT_PULSE,
32 STATE_BIT_SPACE,
33 STATE_TRAILER_PULSE,
34 STATE_TRAILER_SPACE,
Maxim Levitsky39b2c062010-07-31 11:59:18 -030035 STATE_CHECK_REPEAT,
David Härdemanbf670f62010-04-15 18:46:05 -030036};
37
David Härdemanbf670f62010-04-15 18:46:05 -030038/**
39 * ir_jvc_decode() - Decode one JVC pulse or space
David Härdemand8b4b582010-10-29 16:08:23 -030040 * @dev: the struct rc_dev descriptor of the device
David Härdemanbf670f62010-04-15 18:46:05 -030041 * @duration: the struct ir_raw_event descriptor of the pulse/space
42 *
43 * This function returns -EINVAL if the pulse violates the state machine
44 */
David Härdemand8b4b582010-10-29 16:08:23 -030045static int ir_jvc_decode(struct rc_dev *dev, struct ir_raw_event ev)
David Härdemanbf670f62010-04-15 18:46:05 -030046{
David Härdemand8b4b582010-10-29 16:08:23 -030047 struct jvc_dec *data = &dev->raw->jvc;
David Härdemanbf670f62010-04-15 18:46:05 -030048
Mauro Carvalho Chehab52b66142010-11-17 14:20:52 -030049 if (!(dev->raw->enabled_protocols & RC_TYPE_JVC))
David Härdemanbf670f62010-04-15 18:46:05 -030050 return 0;
51
Maxim Levitsky46519182010-10-16 19:56:28 -030052 if (!is_timing_event(ev)) {
53 if (ev.reset)
54 data->state = STATE_INACTIVE;
David Härdemanbf670f62010-04-15 18:46:05 -030055 return 0;
56 }
57
58 if (!geq_margin(ev.duration, JVC_UNIT, JVC_UNIT / 2))
59 goto out;
60
61 IR_dprintk(2, "JVC decode started at state %d (%uus %s)\n",
62 data->state, TO_US(ev.duration), TO_STR(ev.pulse));
63
Maxim Levitsky39b2c062010-07-31 11:59:18 -030064again:
David Härdemanbf670f62010-04-15 18:46:05 -030065 switch (data->state) {
66
67 case STATE_INACTIVE:
68 if (!ev.pulse)
69 break;
70
71 if (!eq_margin(ev.duration, JVC_HEADER_PULSE, JVC_UNIT / 2))
72 break;
73
74 data->count = 0;
75 data->first = true;
76 data->toggle = !data->toggle;
77 data->state = STATE_HEADER_SPACE;
78 return 0;
79
80 case STATE_HEADER_SPACE:
81 if (ev.pulse)
82 break;
83
84 if (!eq_margin(ev.duration, JVC_HEADER_SPACE, JVC_UNIT / 2))
85 break;
86
87 data->state = STATE_BIT_PULSE;
88 return 0;
89
90 case STATE_BIT_PULSE:
91 if (!ev.pulse)
92 break;
93
94 if (!eq_margin(ev.duration, JVC_BIT_PULSE, JVC_UNIT / 2))
95 break;
96
97 data->state = STATE_BIT_SPACE;
98 return 0;
99
100 case STATE_BIT_SPACE:
101 if (ev.pulse)
102 break;
103
David Härdemanc2163692010-06-13 17:29:36 -0300104 data->bits <<= 1;
David Härdemanbf670f62010-04-15 18:46:05 -0300105 if (eq_margin(ev.duration, JVC_BIT_1_SPACE, JVC_UNIT / 2)) {
David Härdemanc2163692010-06-13 17:29:36 -0300106 data->bits |= 1;
David Härdemanbf670f62010-04-15 18:46:05 -0300107 decrease_duration(&ev, JVC_BIT_1_SPACE);
108 } else if (eq_margin(ev.duration, JVC_BIT_0_SPACE, JVC_UNIT / 2))
109 decrease_duration(&ev, JVC_BIT_0_SPACE);
110 else
111 break;
112 data->count++;
113
114 if (data->count == JVC_NBITS)
115 data->state = STATE_TRAILER_PULSE;
116 else
117 data->state = STATE_BIT_PULSE;
118 return 0;
119
120 case STATE_TRAILER_PULSE:
121 if (!ev.pulse)
122 break;
123
124 if (!eq_margin(ev.duration, JVC_TRAILER_PULSE, JVC_UNIT / 2))
125 break;
126
127 data->state = STATE_TRAILER_SPACE;
128 return 0;
129
130 case STATE_TRAILER_SPACE:
131 if (ev.pulse)
132 break;
133
134 if (!geq_margin(ev.duration, JVC_TRAILER_SPACE, JVC_UNIT / 2))
135 break;
136
137 if (data->first) {
138 u32 scancode;
David Härdemanc2163692010-06-13 17:29:36 -0300139 scancode = (bitrev8((data->bits >> 8) & 0xff) << 8) |
140 (bitrev8((data->bits >> 0) & 0xff) << 0);
David Härdemanbf670f62010-04-15 18:46:05 -0300141 IR_dprintk(1, "JVC scancode 0x%04x\n", scancode);
Mauro Carvalho Chehabca866742010-11-17 13:53:11 -0300142 rc_keydown(dev, scancode, data->toggle);
David Härdemanbf670f62010-04-15 18:46:05 -0300143 data->first = false;
David Härdemanc2163692010-06-13 17:29:36 -0300144 data->old_bits = data->bits;
145 } else if (data->bits == data->old_bits) {
David Härdemanbf670f62010-04-15 18:46:05 -0300146 IR_dprintk(1, "JVC repeat\n");
Mauro Carvalho Chehabca866742010-11-17 13:53:11 -0300147 rc_repeat(dev);
David Härdemanbf670f62010-04-15 18:46:05 -0300148 } else {
149 IR_dprintk(1, "JVC invalid repeat msg\n");
150 break;
151 }
152
153 data->count = 0;
Maxim Levitsky39b2c062010-07-31 11:59:18 -0300154 data->state = STATE_CHECK_REPEAT;
David Härdemanbf670f62010-04-15 18:46:05 -0300155 return 0;
Maxim Levitsky39b2c062010-07-31 11:59:18 -0300156
157 case STATE_CHECK_REPEAT:
158 if (!ev.pulse)
159 break;
160
161 if (eq_margin(ev.duration, JVC_HEADER_PULSE, JVC_UNIT / 2))
162 data->state = STATE_INACTIVE;
163 else
164 data->state = STATE_BIT_PULSE;
165 goto again;
David Härdemanbf670f62010-04-15 18:46:05 -0300166 }
167
168out:
169 IR_dprintk(1, "JVC decode failed at state %d (%uus %s)\n",
170 data->state, TO_US(ev.duration), TO_STR(ev.pulse));
171 data->state = STATE_INACTIVE;
172 return -EINVAL;
173}
174
David Härdemanbf670f62010-04-15 18:46:05 -0300175static struct ir_raw_handler jvc_handler = {
Mauro Carvalho Chehab52b66142010-11-17 14:20:52 -0300176 .protocols = RC_TYPE_JVC,
David Härdemanbf670f62010-04-15 18:46:05 -0300177 .decode = ir_jvc_decode,
David Härdemanbf670f62010-04-15 18:46:05 -0300178};
179
180static int __init ir_jvc_decode_init(void)
181{
182 ir_raw_handler_register(&jvc_handler);
183
184 printk(KERN_INFO "IR JVC protocol handler initialized\n");
185 return 0;
186}
187
188static void __exit ir_jvc_decode_exit(void)
189{
190 ir_raw_handler_unregister(&jvc_handler);
191}
192
193module_init(ir_jvc_decode_init);
194module_exit(ir_jvc_decode_exit);
195
196MODULE_LICENSE("GPL");
197MODULE_AUTHOR("David Härdeman <david@hardeman.nu>");
198MODULE_DESCRIPTION("JVC IR protocol decoder");