1 /* ir-sanyo-decoder.c - handle SANYO IR Pulse/Space protocol
2  *
3  * Copyright (C) 2011 by Mauro Carvalho Chehab
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 
39 enum 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  */
55 static 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 	u16 address;
60 	u8 command, not_command;
61 
62 	if (!is_timing_event(ev)) {
63 		if (ev.reset) {
64 			IR_dprintk(1, "SANYO event reset received. reset to state 0\n");
65 			data->state = STATE_INACTIVE;
66 		}
67 		return 0;
68 	}
69 
70 	IR_dprintk(2, "SANYO decode started at state %d (%uus %s)\n",
71 		   data->state, TO_US(ev.duration), TO_STR(ev.pulse));
72 
73 	switch (data->state) {
74 
75 	case STATE_INACTIVE:
76 		if (!ev.pulse)
77 			break;
78 
79 		if (eq_margin(ev.duration, SANYO_HEADER_PULSE, SANYO_UNIT / 2)) {
80 			data->count = 0;
81 			data->state = STATE_HEADER_SPACE;
82 			return 0;
83 		}
84 		break;
85 
86 
87 	case STATE_HEADER_SPACE:
88 		if (ev.pulse)
89 			break;
90 
91 		if (eq_margin(ev.duration, SANYO_HEADER_SPACE, SANYO_UNIT / 2)) {
92 			data->state = STATE_BIT_PULSE;
93 			return 0;
94 		}
95 
96 		break;
97 
98 	case STATE_BIT_PULSE:
99 		if (!ev.pulse)
100 			break;
101 
102 		if (!eq_margin(ev.duration, SANYO_BIT_PULSE, SANYO_UNIT / 2))
103 			break;
104 
105 		data->state = STATE_BIT_SPACE;
106 		return 0;
107 
108 	case STATE_BIT_SPACE:
109 		if (ev.pulse)
110 			break;
111 
112 		if (!data->count && geq_margin(ev.duration, SANYO_REPEAT_SPACE, SANYO_UNIT / 2)) {
113 			if (!dev->keypressed) {
114 				IR_dprintk(1, "SANYO discarding last key repeat: event after key up\n");
115 			} else {
116 				rc_repeat(dev);
117 				IR_dprintk(1, "SANYO repeat last key\n");
118 				data->state = STATE_INACTIVE;
119 			}
120 			return 0;
121 		}
122 
123 		data->bits <<= 1;
124 		if (eq_margin(ev.duration, SANYO_BIT_1_SPACE, SANYO_UNIT / 2))
125 			data->bits |= 1;
126 		else if (!eq_margin(ev.duration, SANYO_BIT_0_SPACE, SANYO_UNIT / 2))
127 			break;
128 		data->count++;
129 
130 		if (data->count == SANYO_NBITS)
131 			data->state = STATE_TRAILER_PULSE;
132 		else
133 			data->state = STATE_BIT_PULSE;
134 
135 		return 0;
136 
137 	case STATE_TRAILER_PULSE:
138 		if (!ev.pulse)
139 			break;
140 
141 		if (!eq_margin(ev.duration, SANYO_TRAILER_PULSE, SANYO_UNIT / 2))
142 			break;
143 
144 		data->state = STATE_TRAILER_SPACE;
145 		return 0;
146 
147 	case STATE_TRAILER_SPACE:
148 		if (ev.pulse)
149 			break;
150 
151 		if (!geq_margin(ev.duration, SANYO_TRAILER_SPACE, SANYO_UNIT / 2))
152 			break;
153 
154 		address     = bitrev16((data->bits >> 29) & 0x1fff) >> 3;
155 		/* not_address = bitrev16((data->bits >> 16) & 0x1fff) >> 3; */
156 		command	    = bitrev8((data->bits >>  8) & 0xff);
157 		not_command = bitrev8((data->bits >>  0) & 0xff);
158 
159 		if ((command ^ not_command) != 0xff) {
160 			IR_dprintk(1, "SANYO checksum error: received 0x%08Lx\n",
161 				   data->bits);
162 			data->state = STATE_INACTIVE;
163 			return 0;
164 		}
165 
166 		scancode = address << 8 | command;
167 		IR_dprintk(1, "SANYO scancode: 0x%06x\n", scancode);
168 		rc_keydown(dev, RC_TYPE_SANYO, scancode, 0);
169 		data->state = STATE_INACTIVE;
170 		return 0;
171 	}
172 
173 	IR_dprintk(1, "SANYO decode failed at count %d state %d (%uus %s)\n",
174 		   data->count, data->state, TO_US(ev.duration), TO_STR(ev.pulse));
175 	data->state = STATE_INACTIVE;
176 	return -EINVAL;
177 }
178 
179 static const struct ir_raw_timings_pd ir_sanyo_timings = {
180 	.header_pulse  = SANYO_HEADER_PULSE,
181 	.header_space  = SANYO_HEADER_SPACE,
182 	.bit_pulse     = SANYO_BIT_PULSE,
183 	.bit_space[0]  = SANYO_BIT_0_SPACE,
184 	.bit_space[1]  = SANYO_BIT_1_SPACE,
185 	.trailer_pulse = SANYO_TRAILER_PULSE,
186 	.trailer_space = SANYO_TRAILER_SPACE,
187 	.msb_first     = 1,
188 };
189 
190 /**
191  * ir_sanyo_encode() - Encode a scancode as a stream of raw events
192  *
193  * @protocol:	protocol to encode
194  * @scancode:	scancode to encode
195  * @events:	array of raw ir events to write into
196  * @max:	maximum size of @events
197  *
198  * Returns:	The number of events written.
199  *		-ENOBUFS if there isn't enough space in the array to fit the
200  *		encoding. In this case all @max events will have been written.
201  */
202 static int ir_sanyo_encode(enum rc_type protocol, u32 scancode,
203 			   struct ir_raw_event *events, unsigned int max)
204 {
205 	struct ir_raw_event *e = events;
206 	int ret;
207 	u64 raw;
208 
209 	raw = ((u64)(bitrev16(scancode >> 8) & 0xfff8) << (8 + 8 + 13 - 3)) |
210 	      ((u64)(bitrev16(~scancode >> 8) & 0xfff8) << (8 + 8 +  0 - 3)) |
211 	      ((bitrev8(scancode) & 0xff) << 8) |
212 	      (bitrev8(~scancode) & 0xff);
213 
214 	ret = ir_raw_gen_pd(&e, max, &ir_sanyo_timings, SANYO_NBITS, raw);
215 	if (ret < 0)
216 		return ret;
217 
218 	return e - events;
219 }
220 
221 static struct ir_raw_handler sanyo_handler = {
222 	.protocols	= RC_BIT_SANYO,
223 	.decode		= ir_sanyo_decode,
224 	.encode		= ir_sanyo_encode,
225 };
226 
227 static int __init ir_sanyo_decode_init(void)
228 {
229 	ir_raw_handler_register(&sanyo_handler);
230 
231 	printk(KERN_INFO "IR SANYO protocol handler initialized\n");
232 	return 0;
233 }
234 
235 static void __exit ir_sanyo_decode_exit(void)
236 {
237 	ir_raw_handler_unregister(&sanyo_handler);
238 }
239 
240 module_init(ir_sanyo_decode_init);
241 module_exit(ir_sanyo_decode_exit);
242 
243 MODULE_LICENSE("GPL");
244 MODULE_AUTHOR("Mauro Carvalho Chehab");
245 MODULE_AUTHOR("Red Hat Inc. (http://www.redhat.com)");
246 MODULE_DESCRIPTION("SANYO IR protocol decoder");
247