1/* ir-sony-decoder.c - handle Sony IR Pulse/Space protocol
2 *
3 * Copyright (C) 2010 by David H��rdeman <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>
16#include <linux/module.h>
17#include "rc-core-priv.h"
18
19#define SONY_UNIT		600000 /* ns */
20#define SONY_HEADER_PULSE	(4 * SONY_UNIT)
21#define	SONY_HEADER_SPACE	(1 * SONY_UNIT)
22#define SONY_BIT_0_PULSE	(1 * SONY_UNIT)
23#define SONY_BIT_1_PULSE	(2 * SONY_UNIT)
24#define SONY_BIT_SPACE		(1 * SONY_UNIT)
25#define SONY_TRAILER_SPACE	(10 * SONY_UNIT) /* minimum */
26
27enum sony_state {
28	STATE_INACTIVE,
29	STATE_HEADER_SPACE,
30	STATE_BIT_PULSE,
31	STATE_BIT_SPACE,
32	STATE_FINISHED,
33};
34
35/**
36 * ir_sony_decode() - Decode one Sony pulse or space
37 * @dev:	the struct rc_dev descriptor of the device
38 * @ev:         the struct ir_raw_event descriptor of the pulse/space
39 *
40 * This function returns -EINVAL if the pulse violates the state machine
41 */
42static int ir_sony_decode(struct rc_dev *dev, struct ir_raw_event ev)
43{
44	struct sony_dec *data = &dev->raw->sony;
45	enum rc_type protocol;
46	u32 scancode;
47	u8 device, subdevice, function;
48
49	if (!(dev->enabled_protocols &
50	      (RC_BIT_SONY12 | RC_BIT_SONY15 | RC_BIT_SONY20)))
51		return 0;
52
53	if (!is_timing_event(ev)) {
54		if (ev.reset)
55			data->state = STATE_INACTIVE;
56		return 0;
57	}
58
59	if (!geq_margin(ev.duration, SONY_UNIT, SONY_UNIT / 2))
60		goto out;
61
62	IR_dprintk(2, "Sony decode started at state %d (%uus %s)\n",
63		   data->state, TO_US(ev.duration), TO_STR(ev.pulse));
64
65	switch (data->state) {
66
67	case STATE_INACTIVE:
68		if (!ev.pulse)
69			break;
70
71		if (!eq_margin(ev.duration, SONY_HEADER_PULSE, SONY_UNIT / 2))
72			break;
73
74		data->count = 0;
75		data->state = STATE_HEADER_SPACE;
76		return 0;
77
78	case STATE_HEADER_SPACE:
79		if (ev.pulse)
80			break;
81
82		if (!eq_margin(ev.duration, SONY_HEADER_SPACE, SONY_UNIT / 2))
83			break;
84
85		data->state = STATE_BIT_PULSE;
86		return 0;
87
88	case STATE_BIT_PULSE:
89		if (!ev.pulse)
90			break;
91
92		data->bits <<= 1;
93		if (eq_margin(ev.duration, SONY_BIT_1_PULSE, SONY_UNIT / 2))
94			data->bits |= 1;
95		else if (!eq_margin(ev.duration, SONY_BIT_0_PULSE, SONY_UNIT / 2))
96			break;
97
98		data->count++;
99		data->state = STATE_BIT_SPACE;
100		return 0;
101
102	case STATE_BIT_SPACE:
103		if (ev.pulse)
104			break;
105
106		if (!geq_margin(ev.duration, SONY_BIT_SPACE, SONY_UNIT / 2))
107			break;
108
109		decrease_duration(&ev, SONY_BIT_SPACE);
110
111		if (!geq_margin(ev.duration, SONY_UNIT, SONY_UNIT / 2)) {
112			data->state = STATE_BIT_PULSE;
113			return 0;
114		}
115
116		data->state = STATE_FINISHED;
117		/* Fall through */
118
119	case STATE_FINISHED:
120		if (ev.pulse)
121			break;
122
123		if (!geq_margin(ev.duration, SONY_TRAILER_SPACE, SONY_UNIT / 2))
124			break;
125
126		switch (data->count) {
127		case 12:
128			if (!(dev->enabled_protocols & RC_BIT_SONY12))
129				goto finish_state_machine;
130
131			device    = bitrev8((data->bits <<  3) & 0xF8);
132			subdevice = 0;
133			function  = bitrev8((data->bits >>  4) & 0xFE);
134			protocol = RC_TYPE_SONY12;
135			break;
136		case 15:
137			if (!(dev->enabled_protocols & RC_BIT_SONY15))
138				goto finish_state_machine;
139
140			device    = bitrev8((data->bits >>  0) & 0xFF);
141			subdevice = 0;
142			function  = bitrev8((data->bits >>  7) & 0xFE);
143			protocol = RC_TYPE_SONY15;
144			break;
145		case 20:
146			if (!(dev->enabled_protocols & RC_BIT_SONY20))
147				goto finish_state_machine;
148
149			device    = bitrev8((data->bits >>  5) & 0xF8);
150			subdevice = bitrev8((data->bits >>  0) & 0xFF);
151			function  = bitrev8((data->bits >> 12) & 0xFE);
152			protocol = RC_TYPE_SONY20;
153			break;
154		default:
155			IR_dprintk(1, "Sony invalid bitcount %u\n", data->count);
156			goto out;
157		}
158
159		scancode = device << 16 | subdevice << 8 | function;
160		IR_dprintk(1, "Sony(%u) scancode 0x%05x\n", data->count, scancode);
161		rc_keydown(dev, protocol, scancode, 0);
162		goto finish_state_machine;
163	}
164
165out:
166	IR_dprintk(1, "Sony decode failed at state %d (%uus %s)\n",
167		   data->state, TO_US(ev.duration), TO_STR(ev.pulse));
168	data->state = STATE_INACTIVE;
169	return -EINVAL;
170
171finish_state_machine:
172	data->state = STATE_INACTIVE;
173	return 0;
174}
175
176static struct ir_raw_handler sony_handler = {
177	.protocols	= RC_BIT_SONY12 | RC_BIT_SONY15 | RC_BIT_SONY20,
178	.decode		= ir_sony_decode,
179};
180
181static int __init ir_sony_decode_init(void)
182{
183	ir_raw_handler_register(&sony_handler);
184
185	printk(KERN_INFO "IR Sony protocol handler initialized\n");
186	return 0;
187}
188
189static void __exit ir_sony_decode_exit(void)
190{
191	ir_raw_handler_unregister(&sony_handler);
192}
193
194module_init(ir_sony_decode_init);
195module_exit(ir_sony_decode_exit);
196
197MODULE_LICENSE("GPL");
198MODULE_AUTHOR("David H��rdeman <david@hardeman.nu>");
199MODULE_DESCRIPTION("Sony IR protocol decoder");
200