aboutsummaryrefslogtreecommitdiffstats
path: root/drivers/media/rc/ir-jvc-decoder.c
blob: cfe0e70440a519a7acaa3368e3df3a4994beeef7 (plain)
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
/* ir-jvc-decoder.c - handle JVC IR Pulse/Space protocol
 *
 * Copyright (C) 2010 by David Härdeman <david@hardeman.nu>
 *
 * 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 "rc-core-priv.h"

#define JVC_NBITS		16		/* dev(8) + func(8) */
#define JVC_UNIT		525000		/* ns */
#define JVC_HEADER_PULSE	(16 * JVC_UNIT) /* lack of header -> repeat */
#define JVC_HEADER_SPACE	(8  * JVC_UNIT)
#define JVC_BIT_PULSE		(1  * JVC_UNIT)
#define JVC_BIT_0_SPACE		(1  * JVC_UNIT)
#define JVC_BIT_1_SPACE		(3  * JVC_UNIT)
#define JVC_TRAILER_PULSE	(1  * JVC_UNIT)
#define	JVC_TRAILER_SPACE	(35 * JVC_UNIT)

enum jvc_state {
	STATE_INACTIVE,
	STATE_HEADER_SPACE,
	STATE_BIT_PULSE,
	STATE_BIT_SPACE,
	STATE_TRAILER_PULSE,
	STATE_TRAILER_SPACE,
	STATE_CHECK_REPEAT,
};

/**
 * ir_jvc_decode() - Decode one JVC 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_jvc_decode(struct rc_dev *dev, struct ir_raw_event ev)
{
	struct jvc_dec *data = &dev->raw->jvc;

	if (!(dev->raw->enabled_protocols & IR_TYPE_JVC))
		return 0;

	if (!is_timing_event(ev)) {
		if (ev.reset)
			data->state = STATE_INACTIVE;
		return 0;
	}

	if (!geq_margin(ev.duration, JVC_UNIT, JVC_UNIT / 2))
		goto out;

	IR_dprintk(2, "JVC decode started at state %d (%uus %s)\n",
		   data->state, TO_US(ev.duration), TO_STR(ev.pulse));

again:
	switch (data->state) {

	case STATE_INACTIVE:
		if (!ev.pulse)
			break;

		if (!eq_margin(ev.duration, JVC_HEADER_PULSE, JVC_UNIT / 2))
			break;

		data->count = 0;
		data->first = true;
		data->toggle = !data->toggle;
		data->state = STATE_HEADER_SPACE;
		return 0;

	case STATE_HEADER_SPACE:
		if (ev.pulse)
			break;

		if (!eq_margin(ev.duration, JVC_HEADER_SPACE, JVC_UNIT / 2))
			break;

		data->state = STATE_BIT_PULSE;
		return 0;

	case STATE_BIT_PULSE:
		if (!ev.pulse)
			break;

		if (!eq_margin(ev.duration, JVC_BIT_PULSE, JVC_UNIT / 2))
			break;

		data->state = STATE_BIT_SPACE;
		return 0;

	case STATE_BIT_SPACE:
		if (ev.pulse)
			break;

		data->bits <<= 1;
		if (eq_margin(ev.duration, JVC_BIT_1_SPACE, JVC_UNIT / 2)) {
			data->bits |= 1;
			decrease_duration(&ev, JVC_BIT_1_SPACE);
		} else if (eq_margin(ev.duration, JVC_BIT_0_SPACE, JVC_UNIT / 2))
			decrease_duration(&ev, JVC_BIT_0_SPACE);
		else
			break;
		data->count++;

		if (data->count == JVC_NBITS)
			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, JVC_TRAILER_PULSE, JVC_UNIT / 2))
			break;

		data->state = STATE_TRAILER_SPACE;
		return 0;

	case STATE_TRAILER_SPACE:
		if (ev.pulse)
			break;

		if (!geq_margin(ev.duration, JVC_TRAILER_SPACE, JVC_UNIT / 2))
			break;

		if (data->first) {
			u32 scancode;
			scancode = (bitrev8((data->bits >> 8) & 0xff) << 8) |
				   (bitrev8((data->bits >> 0) & 0xff) << 0);
			IR_dprintk(1, "JVC scancode 0x%04x\n", scancode);
			ir_keydown(dev, scancode, data->toggle);
			data->first = false;
			data->old_bits = data->bits;
		} else if (data->bits == data->old_bits) {
			IR_dprintk(1, "JVC repeat\n");
			ir_repeat(dev);
		} else {
			IR_dprintk(1, "JVC invalid repeat msg\n");
			break;
		}

		data->count = 0;
		data->state = STATE_CHECK_REPEAT;
		return 0;

	case STATE_CHECK_REPEAT:
		if (!ev.pulse)
			break;

		if (eq_margin(ev.duration, JVC_HEADER_PULSE, JVC_UNIT / 2))
			data->state = STATE_INACTIVE;
  else
			data->state = STATE_BIT_PULSE;
		goto again;
	}

out:
	IR_dprintk(1, "JVC decode failed at state %d (%uus %s)\n",
		   data->state, TO_US(ev.duration), TO_STR(ev.pulse));
	data->state = STATE_INACTIVE;
	return -EINVAL;
}

static struct ir_raw_handler jvc_handler = {
	.protocols	= IR_TYPE_JVC,
	.decode		= ir_jvc_decode,
};

static int __init ir_jvc_decode_init(void)
{
	ir_raw_handler_register(&jvc_handler);

	printk(KERN_INFO "IR JVC protocol handler initialized\n");
	return 0;
}

static void __exit ir_jvc_decode_exit(void)
{
	ir_raw_handler_unregister(&jvc_handler);
}

module_init(ir_jvc_decode_init);
module_exit(ir_jvc_decode_exit);

MODULE_LICENSE("GPL");
MODULE_AUTHOR("David Härdeman <david@hardeman.nu>");
MODULE_DESCRIPTION("JVC IR protocol decoder");