1/* ir-sanyo-decoder.c - handle SANYO IR Pulse/Space protocol
2 *
3 * Copyright (C) 2011 by Mauro Carvalho Chehab <mchehab@redhat.com>
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 * This protocol uses the NEC protocol timings. However, data is formatted as:
15 *	13 bits Custom Code
16 *	13 bits NOT(Custom Code)
17 *	8 bits Key data
18 *	8 bits NOT(Key data)
19 *
20 * According with LIRC, this protocol is used on Sanyo, Aiwa and Chinon
21 * Information for this protocol is available at the Sanyo LC7461 datasheet.
22 */
23
24#include <linux/module.h>
25#include <linux/bitrev.h>
26#include "rc-core-priv.h"
27
28#define SANYO_NBITS		(13+13+8+8)
29#define SANYO_UNIT		562500  /* ns */
30#define SANYO_HEADER_PULSE	(16  * SANYO_UNIT)
31#define SANYO_HEADER_SPACE	(8   * SANYO_UNIT)
32#define SANYO_BIT_PULSE		(1   * SANYO_UNIT)
33#define SANYO_BIT_0_SPACE	(1   * SANYO_UNIT)
34#define SANYO_BIT_1_SPACE	(3   * SANYO_UNIT)
35#define SANYO_REPEAT_SPACE	(150 * SANYO_UNIT)
36#define	SANYO_TRAILER_PULSE	(1   * SANYO_UNIT)
37#define	SANYO_TRAILER_SPACE	(10  * SANYO_UNIT)	/* in fact, 42 */
38
39enum sanyo_state {
40	STATE_INACTIVE,
41	STATE_HEADER_SPACE,
42	STATE_BIT_PULSE,
43	STATE_BIT_SPACE,
44	STATE_TRAILER_PULSE,
45	STATE_TRAILER_SPACE,
46};
47
48/**
49 * ir_sanyo_decode() - Decode one SANYO pulse or space
50 * @dev:	the struct rc_dev descriptor of the device
51 * @duration:	the struct ir_raw_event descriptor of the pulse/space
52 *
53 * This function returns -EINVAL if the pulse violates the state machine
54 */
55static int ir_sanyo_decode(struct rc_dev *dev, struct ir_raw_event ev)
56{
57	struct sanyo_dec *data = &dev->raw->sanyo;
58	u32 scancode;
59	u8 address, not_address, command, not_command;
60
61	if (!(dev->raw->enabled_protocols & RC_TYPE_SANYO))
62		return 0;
63
64	if (!is_timing_event(ev)) {
65		if (ev.reset) {
66			IR_dprintk(1, "SANYO event reset received. reset to state 0\n");
67			data->state = STATE_INACTIVE;
68		}
69		return 0;
70	}
71
72	IR_dprintk(2, "SANYO decode started at state %d (%uus %s)\n",
73		   data->state, TO_US(ev.duration), TO_STR(ev.pulse));
74
75	switch (data->state) {
76
77	case STATE_INACTIVE:
78		if (!ev.pulse)
79			break;
80
81		if (eq_margin(ev.duration, SANYO_HEADER_PULSE, SANYO_UNIT / 2)) {
82			data->count = 0;
83			data->state = STATE_HEADER_SPACE;
84			return 0;
85		}
86		break;
87
88
89	case STATE_HEADER_SPACE:
90		if (ev.pulse)
91			break;
92
93		if (eq_margin(ev.duration, SANYO_HEADER_SPACE, SANYO_UNIT / 2)) {
94			data->state = STATE_BIT_PULSE;
95			return 0;
96		}
97
98		break;
99
100	case STATE_BIT_PULSE:
101		if (!ev.pulse)
102			break;
103
104		if (!eq_margin(ev.duration, SANYO_BIT_PULSE, SANYO_UNIT / 2))
105			break;
106
107		data->state = STATE_BIT_SPACE;
108		return 0;
109
110	case STATE_BIT_SPACE:
111		if (ev.pulse)
112			break;
113
114		if (!data->count && geq_margin(ev.duration, SANYO_REPEAT_SPACE, SANYO_UNIT / 2)) {
115			if (!dev->keypressed) {
116				IR_dprintk(1, "SANYO discarding last key repeat: event after key up\n");
117			} else {
118				rc_repeat(dev);
119				IR_dprintk(1, "SANYO repeat last key\n");
120				data->state = STATE_INACTIVE;
121			}
122			return 0;
123		}
124
125		data->bits <<= 1;
126		if (eq_margin(ev.duration, SANYO_BIT_1_SPACE, SANYO_UNIT / 2))
127			data->bits |= 1;
128		else if (!eq_margin(ev.duration, SANYO_BIT_0_SPACE, SANYO_UNIT / 2))
129			break;
130		data->count++;
131
132		if (data->count == SANYO_NBITS)
133			data->state = STATE_TRAILER_PULSE;
134		else
135			data->state = STATE_BIT_PULSE;
136
137		return 0;
138
139	case STATE_TRAILER_PULSE:
140		if (!ev.pulse)
141			break;
142
143		if (!eq_margin(ev.duration, SANYO_TRAILER_PULSE, SANYO_UNIT / 2))
144			break;
145
146		data->state = STATE_TRAILER_SPACE;
147		return 0;
148
149	case STATE_TRAILER_SPACE:
150		if (ev.pulse)
151			break;
152
153		if (!geq_margin(ev.duration, SANYO_TRAILER_SPACE, SANYO_UNIT / 2))
154			break;
155
156		address     = bitrev16((data->bits >> 29) & 0x1fff) >> 3;
157		not_address = bitrev16((data->bits >> 16) & 0x1fff) >> 3;
158		command	    = bitrev8((data->bits >>  8) & 0xff);
159		not_command = bitrev8((data->bits >>  0) & 0xff);
160
161		if ((command ^ not_command) != 0xff) {
162			IR_dprintk(1, "SANYO checksum error: received 0x%08Lx\n",
163				   data->bits);
164			data->state = STATE_INACTIVE;
165			return 0;
166		}
167
168		scancode = address << 8 | command;
169		IR_dprintk(1, "SANYO scancode: 0x%06x\n", scancode);
170		rc_keydown(dev, scancode, 0);
171		data->state = STATE_INACTIVE;
172		return 0;
173	}
174
175	IR_dprintk(1, "SANYO decode failed at count %d state %d (%uus %s)\n",
176		   data->count, data->state, TO_US(ev.duration), TO_STR(ev.pulse));
177	data->state = STATE_INACTIVE;
178	return -EINVAL;
179}
180
181static struct ir_raw_handler sanyo_handler = {
182	.protocols	= RC_TYPE_SANYO,
183	.decode		= ir_sanyo_decode,
184};
185
186static int __init ir_sanyo_decode_init(void)
187{
188	ir_raw_handler_register(&sanyo_handler);
189
190	printk(KERN_INFO "IR SANYO protocol handler initialized\n");
191	return 0;
192}
193
194static void __exit ir_sanyo_decode_exit(void)
195{
196	ir_raw_handler_unregister(&sanyo_handler);
197}
198
199module_init(ir_sanyo_decode_init);
200module_exit(ir_sanyo_decode_exit);
201
202MODULE_LICENSE("GPL");
203MODULE_AUTHOR("Mauro Carvalho Chehab <mchehab@redhat.com>");
204MODULE_AUTHOR("Red Hat Inc. (http://www.redhat.com)");
205MODULE_DESCRIPTION("SANYO IR protocol decoder");
206