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 	enum rc_proto protocol;
46 	u32 scancode;
47 	u8 device, subdevice, function;
48 
49 	if (!is_timing_event(ev)) {
50 		if (ev.reset)
51 			data->state = STATE_INACTIVE;
52 		return 0;
53 	}
54 
55 	if (!geq_margin(ev.duration, SONY_UNIT, SONY_UNIT / 2))
56 		goto out;
57 
58 	dev_dbg(&dev->dev, "Sony decode started at state %d (%uus %s)\n",
59 		data->state, TO_US(ev.duration), TO_STR(ev.pulse));
60 
61 	switch (data->state) {
62 
63 	case STATE_INACTIVE:
64 		if (!ev.pulse)
65 			break;
66 
67 		if (!eq_margin(ev.duration, SONY_HEADER_PULSE, SONY_UNIT / 2))
68 			break;
69 
70 		data->count = 0;
71 		data->state = STATE_HEADER_SPACE;
72 		return 0;
73 
74 	case STATE_HEADER_SPACE:
75 		if (ev.pulse)
76 			break;
77 
78 		if (!eq_margin(ev.duration, SONY_HEADER_SPACE, SONY_UNIT / 2))
79 			break;
80 
81 		data->state = STATE_BIT_PULSE;
82 		return 0;
83 
84 	case STATE_BIT_PULSE:
85 		if (!ev.pulse)
86 			break;
87 
88 		data->bits <<= 1;
89 		if (eq_margin(ev.duration, SONY_BIT_1_PULSE, SONY_UNIT / 2))
90 			data->bits |= 1;
91 		else if (!eq_margin(ev.duration, SONY_BIT_0_PULSE, SONY_UNIT / 2))
92 			break;
93 
94 		data->count++;
95 		data->state = STATE_BIT_SPACE;
96 		return 0;
97 
98 	case STATE_BIT_SPACE:
99 		if (ev.pulse)
100 			break;
101 
102 		if (!geq_margin(ev.duration, SONY_BIT_SPACE, SONY_UNIT / 2))
103 			break;
104 
105 		decrease_duration(&ev, SONY_BIT_SPACE);
106 
107 		if (!geq_margin(ev.duration, SONY_UNIT, SONY_UNIT / 2)) {
108 			data->state = STATE_BIT_PULSE;
109 			return 0;
110 		}
111 
112 		data->state = STATE_FINISHED;
113 		/* Fall through */
114 
115 	case STATE_FINISHED:
116 		if (ev.pulse)
117 			break;
118 
119 		if (!geq_margin(ev.duration, SONY_TRAILER_SPACE, SONY_UNIT / 2))
120 			break;
121 
122 		switch (data->count) {
123 		case 12:
124 			if (!(dev->enabled_protocols & RC_PROTO_BIT_SONY12))
125 				goto finish_state_machine;
126 
127 			device    = bitrev8((data->bits <<  3) & 0xF8);
128 			subdevice = 0;
129 			function  = bitrev8((data->bits >>  4) & 0xFE);
130 			protocol = RC_PROTO_SONY12;
131 			break;
132 		case 15:
133 			if (!(dev->enabled_protocols & RC_PROTO_BIT_SONY15))
134 				goto finish_state_machine;
135 
136 			device    = bitrev8((data->bits >>  0) & 0xFF);
137 			subdevice = 0;
138 			function  = bitrev8((data->bits >>  7) & 0xFE);
139 			protocol = RC_PROTO_SONY15;
140 			break;
141 		case 20:
142 			if (!(dev->enabled_protocols & RC_PROTO_BIT_SONY20))
143 				goto finish_state_machine;
144 
145 			device    = bitrev8((data->bits >>  5) & 0xF8);
146 			subdevice = bitrev8((data->bits >>  0) & 0xFF);
147 			function  = bitrev8((data->bits >> 12) & 0xFE);
148 			protocol = RC_PROTO_SONY20;
149 			break;
150 		default:
151 			dev_dbg(&dev->dev, "Sony invalid bitcount %u\n",
152 				data->count);
153 			goto out;
154 		}
155 
156 		scancode = device << 16 | subdevice << 8 | function;
157 		dev_dbg(&dev->dev, "Sony(%u) scancode 0x%05x\n", data->count,
158 			scancode);
159 		rc_keydown(dev, protocol, scancode, 0);
160 		goto finish_state_machine;
161 	}
162 
163 out:
164 	dev_dbg(&dev->dev, "Sony decode failed at state %d (%uus %s)\n",
165 		data->state, TO_US(ev.duration), TO_STR(ev.pulse));
166 	data->state = STATE_INACTIVE;
167 	return -EINVAL;
168 
169 finish_state_machine:
170 	data->state = STATE_INACTIVE;
171 	return 0;
172 }
173 
174 static const struct ir_raw_timings_pl ir_sony_timings = {
175 	.header_pulse  = SONY_HEADER_PULSE,
176 	.bit_space     = SONY_BIT_SPACE,
177 	.bit_pulse[0]  = SONY_BIT_0_PULSE,
178 	.bit_pulse[1]  = SONY_BIT_1_PULSE,
179 	.trailer_space = SONY_TRAILER_SPACE + SONY_BIT_SPACE,
180 	.msb_first     = 0,
181 };
182 
183 /**
184  * ir_sony_encode() - Encode a scancode as a stream of raw events
185  *
186  * @protocol:	protocol to encode
187  * @scancode:	scancode to encode
188  * @events:	array of raw ir events to write into
189  * @max:	maximum size of @events
190  *
191  * Returns:	The number of events written.
192  *		-ENOBUFS if there isn't enough space in the array to fit the
193  *		encoding. In this case all @max events will have been written.
194  */
195 static int ir_sony_encode(enum rc_proto protocol, u32 scancode,
196 			  struct ir_raw_event *events, unsigned int max)
197 {
198 	struct ir_raw_event *e = events;
199 	u32 raw, len;
200 	int ret;
201 
202 	if (protocol == RC_PROTO_SONY12) {
203 		raw = (scancode & 0x7f) | ((scancode & 0x1f0000) >> 9);
204 		len = 12;
205 	} else if (protocol == RC_PROTO_SONY15) {
206 		raw = (scancode & 0x7f) | ((scancode & 0xff0000) >> 9);
207 		len = 15;
208 	} else {
209 		raw = (scancode & 0x7f) | ((scancode & 0x1f0000) >> 9) |
210 		       ((scancode & 0xff00) << 4);
211 		len = 20;
212 	}
213 
214 	ret = ir_raw_gen_pl(&e, max, &ir_sony_timings, len, raw);
215 	if (ret < 0)
216 		return ret;
217 
218 	return e - events;
219 }
220 
221 static struct ir_raw_handler sony_handler = {
222 	.protocols	= RC_PROTO_BIT_SONY12 | RC_PROTO_BIT_SONY15 |
223 							RC_PROTO_BIT_SONY20,
224 	.decode		= ir_sony_decode,
225 	.encode		= ir_sony_encode,
226 	.carrier	= 40000,
227 	.min_timeout	= SONY_TRAILER_SPACE,
228 };
229 
230 static int __init ir_sony_decode_init(void)
231 {
232 	ir_raw_handler_register(&sony_handler);
233 
234 	printk(KERN_INFO "IR Sony protocol handler initialized\n");
235 	return 0;
236 }
237 
238 static void __exit ir_sony_decode_exit(void)
239 {
240 	ir_raw_handler_unregister(&sony_handler);
241 }
242 
243 module_init(ir_sony_decode_init);
244 module_exit(ir_sony_decode_exit);
245 
246 MODULE_LICENSE("GPL");
247 MODULE_AUTHOR("David Härdeman <david@hardeman.nu>");
248 MODULE_DESCRIPTION("Sony IR protocol decoder");
249