xref: /linux/drivers/media/rc/ir-sony-decoder.c (revision b889fcf63cb62e7fdb7816565e28f44dbe4a76a5)
1 /* ir-sony-decoder.c - handle Sony 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>
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 
27 enum 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  */
42 static int ir_sony_decode(struct rc_dev *dev, struct ir_raw_event ev)
43 {
44 	struct sony_dec *data = &dev->raw->sony;
45 	u32 scancode;
46 	u8 device, subdevice, function;
47 
48 	if (!(dev->raw->enabled_protocols &
49 	      (RC_BIT_SONY12 | RC_BIT_SONY15 | RC_BIT_SONY20)))
50 		return 0;
51 
52 	if (!is_timing_event(ev)) {
53 		if (ev.reset)
54 			data->state = STATE_INACTIVE;
55 		return 0;
56 	}
57 
58 	if (!geq_margin(ev.duration, SONY_UNIT, SONY_UNIT / 2))
59 		goto out;
60 
61 	IR_dprintk(2, "Sony decode started at state %d (%uus %s)\n",
62 		   data->state, TO_US(ev.duration), TO_STR(ev.pulse));
63 
64 	switch (data->state) {
65 
66 	case STATE_INACTIVE:
67 		if (!ev.pulse)
68 			break;
69 
70 		if (!eq_margin(ev.duration, SONY_HEADER_PULSE, SONY_UNIT / 2))
71 			break;
72 
73 		data->count = 0;
74 		data->state = STATE_HEADER_SPACE;
75 		return 0;
76 
77 	case STATE_HEADER_SPACE:
78 		if (ev.pulse)
79 			break;
80 
81 		if (!eq_margin(ev.duration, SONY_HEADER_SPACE, SONY_UNIT / 2))
82 			break;
83 
84 		data->state = STATE_BIT_PULSE;
85 		return 0;
86 
87 	case STATE_BIT_PULSE:
88 		if (!ev.pulse)
89 			break;
90 
91 		data->bits <<= 1;
92 		if (eq_margin(ev.duration, SONY_BIT_1_PULSE, SONY_UNIT / 2))
93 			data->bits |= 1;
94 		else if (!eq_margin(ev.duration, SONY_BIT_0_PULSE, SONY_UNIT / 2))
95 			break;
96 
97 		data->count++;
98 		data->state = STATE_BIT_SPACE;
99 		return 0;
100 
101 	case STATE_BIT_SPACE:
102 		if (ev.pulse)
103 			break;
104 
105 		if (!geq_margin(ev.duration, SONY_BIT_SPACE, SONY_UNIT / 2))
106 			break;
107 
108 		decrease_duration(&ev, SONY_BIT_SPACE);
109 
110 		if (!geq_margin(ev.duration, SONY_UNIT, SONY_UNIT / 2)) {
111 			data->state = STATE_BIT_PULSE;
112 			return 0;
113 		}
114 
115 		data->state = STATE_FINISHED;
116 		/* Fall through */
117 
118 	case STATE_FINISHED:
119 		if (ev.pulse)
120 			break;
121 
122 		if (!geq_margin(ev.duration, SONY_TRAILER_SPACE, SONY_UNIT / 2))
123 			break;
124 
125 		switch (data->count) {
126 		case 12:
127 			if (!(dev->raw->enabled_protocols & RC_BIT_SONY12)) {
128 				data->state = STATE_INACTIVE;
129 				return 0;
130 			}
131 			device    = bitrev8((data->bits <<  3) & 0xF8);
132 			subdevice = 0;
133 			function  = bitrev8((data->bits >>  4) & 0xFE);
134 			break;
135 		case 15:
136 			if (!(dev->raw->enabled_protocols & RC_BIT_SONY15)) {
137 				data->state = STATE_INACTIVE;
138 				return 0;
139 			}
140 			device    = bitrev8((data->bits >>  0) & 0xFF);
141 			subdevice = 0;
142 			function  = bitrev8((data->bits >>  7) & 0xFE);
143 			break;
144 		case 20:
145 			if (!(dev->raw->enabled_protocols & RC_BIT_SONY20)) {
146 				data->state = STATE_INACTIVE;
147 				return 0;
148 			}
149 			device    = bitrev8((data->bits >>  5) & 0xF8);
150 			subdevice = bitrev8((data->bits >>  0) & 0xFF);
151 			function  = bitrev8((data->bits >> 12) & 0xFE);
152 			break;
153 		default:
154 			IR_dprintk(1, "Sony invalid bitcount %u\n", data->count);
155 			goto out;
156 		}
157 
158 		scancode = device << 16 | subdevice << 8 | function;
159 		IR_dprintk(1, "Sony(%u) scancode 0x%05x\n", data->count, scancode);
160 		rc_keydown(dev, scancode, 0);
161 		data->state = STATE_INACTIVE;
162 		return 0;
163 	}
164 
165 out:
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 }
171 
172 static struct ir_raw_handler sony_handler = {
173 	.protocols	= RC_BIT_SONY12 | RC_BIT_SONY15 | RC_BIT_SONY20,
174 	.decode		= ir_sony_decode,
175 };
176 
177 static int __init ir_sony_decode_init(void)
178 {
179 	ir_raw_handler_register(&sony_handler);
180 
181 	printk(KERN_INFO "IR Sony protocol handler initialized\n");
182 	return 0;
183 }
184 
185 static void __exit ir_sony_decode_exit(void)
186 {
187 	ir_raw_handler_unregister(&sony_handler);
188 }
189 
190 module_init(ir_sony_decode_init);
191 module_exit(ir_sony_decode_exit);
192 
193 MODULE_LICENSE("GPL");
194 MODULE_AUTHOR("David Härdeman <david@hardeman.nu>");
195 MODULE_DESCRIPTION("Sony IR protocol decoder");
196