1 // SPDX-License-Identifier: GPL-2.0
2 // ir-sanyo-decoder.c - handle SANYO IR Pulse/Space protocol
3 //
4 // Copyright (C) 2011 by Mauro Carvalho Chehab
5 //
6 // This protocol uses the NEC protocol timings. However, data is formatted as:
7 //	13 bits Custom Code
8 //	13 bits NOT(Custom Code)
9 //	8 bits Key data
10 //	8 bits NOT(Key data)
11 //
12 // According with LIRC, this protocol is used on Sanyo, Aiwa and Chinon
13 // Information for this protocol is available at the Sanyo LC7461 datasheet.
14 
15 #include <linux/module.h>
16 #include <linux/bitrev.h>
17 #include "rc-core-priv.h"
18 
19 #define SANYO_NBITS		(13+13+8+8)
20 #define SANYO_UNIT		562500  /* ns */
21 #define SANYO_HEADER_PULSE	(16  * SANYO_UNIT)
22 #define SANYO_HEADER_SPACE	(8   * SANYO_UNIT)
23 #define SANYO_BIT_PULSE		(1   * SANYO_UNIT)
24 #define SANYO_BIT_0_SPACE	(1   * SANYO_UNIT)
25 #define SANYO_BIT_1_SPACE	(3   * SANYO_UNIT)
26 #define SANYO_REPEAT_SPACE	(150 * SANYO_UNIT)
27 #define	SANYO_TRAILER_PULSE	(1   * SANYO_UNIT)
28 #define	SANYO_TRAILER_SPACE	(10  * SANYO_UNIT)	/* in fact, 42 */
29 
30 enum sanyo_state {
31 	STATE_INACTIVE,
32 	STATE_HEADER_SPACE,
33 	STATE_BIT_PULSE,
34 	STATE_BIT_SPACE,
35 	STATE_TRAILER_PULSE,
36 	STATE_TRAILER_SPACE,
37 };
38 
39 /**
40  * ir_sanyo_decode() - Decode one SANYO pulse or space
41  * @dev:	the struct rc_dev descriptor of the device
42  * @ev:		the struct ir_raw_event descriptor of the pulse/space
43  *
44  * This function returns -EINVAL if the pulse violates the state machine
45  */
46 static int ir_sanyo_decode(struct rc_dev *dev, struct ir_raw_event ev)
47 {
48 	struct sanyo_dec *data = &dev->raw->sanyo;
49 	u32 scancode;
50 	u16 address;
51 	u8 command, not_command;
52 
53 	if (!is_timing_event(ev)) {
54 		if (ev.reset) {
55 			dev_dbg(&dev->dev, "SANYO event reset received. reset to state 0\n");
56 			data->state = STATE_INACTIVE;
57 		}
58 		return 0;
59 	}
60 
61 	dev_dbg(&dev->dev, "SANYO 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, SANYO_HEADER_PULSE, SANYO_UNIT / 2)) {
71 			data->count = 0;
72 			data->state = STATE_HEADER_SPACE;
73 			return 0;
74 		}
75 		break;
76 
77 
78 	case STATE_HEADER_SPACE:
79 		if (ev.pulse)
80 			break;
81 
82 		if (eq_margin(ev.duration, SANYO_HEADER_SPACE, SANYO_UNIT / 2)) {
83 			data->state = STATE_BIT_PULSE;
84 			return 0;
85 		}
86 
87 		break;
88 
89 	case STATE_BIT_PULSE:
90 		if (!ev.pulse)
91 			break;
92 
93 		if (!eq_margin(ev.duration, SANYO_BIT_PULSE, SANYO_UNIT / 2))
94 			break;
95 
96 		data->state = STATE_BIT_SPACE;
97 		return 0;
98 
99 	case STATE_BIT_SPACE:
100 		if (ev.pulse)
101 			break;
102 
103 		if (!data->count && geq_margin(ev.duration, SANYO_REPEAT_SPACE, SANYO_UNIT / 2)) {
104 			rc_repeat(dev);
105 			dev_dbg(&dev->dev, "SANYO repeat last key\n");
106 			data->state = STATE_INACTIVE;
107 			return 0;
108 		}
109 
110 		data->bits <<= 1;
111 		if (eq_margin(ev.duration, SANYO_BIT_1_SPACE, SANYO_UNIT / 2))
112 			data->bits |= 1;
113 		else if (!eq_margin(ev.duration, SANYO_BIT_0_SPACE, SANYO_UNIT / 2))
114 			break;
115 		data->count++;
116 
117 		if (data->count == SANYO_NBITS)
118 			data->state = STATE_TRAILER_PULSE;
119 		else
120 			data->state = STATE_BIT_PULSE;
121 
122 		return 0;
123 
124 	case STATE_TRAILER_PULSE:
125 		if (!ev.pulse)
126 			break;
127 
128 		if (!eq_margin(ev.duration, SANYO_TRAILER_PULSE, SANYO_UNIT / 2))
129 			break;
130 
131 		data->state = STATE_TRAILER_SPACE;
132 		return 0;
133 
134 	case STATE_TRAILER_SPACE:
135 		if (ev.pulse)
136 			break;
137 
138 		if (!geq_margin(ev.duration, SANYO_TRAILER_SPACE, SANYO_UNIT / 2))
139 			break;
140 
141 		address     = bitrev16((data->bits >> 29) & 0x1fff) >> 3;
142 		/* not_address = bitrev16((data->bits >> 16) & 0x1fff) >> 3; */
143 		command	    = bitrev8((data->bits >>  8) & 0xff);
144 		not_command = bitrev8((data->bits >>  0) & 0xff);
145 
146 		if ((command ^ not_command) != 0xff) {
147 			dev_dbg(&dev->dev, "SANYO checksum error: received 0x%08llx\n",
148 				data->bits);
149 			data->state = STATE_INACTIVE;
150 			return 0;
151 		}
152 
153 		scancode = address << 8 | command;
154 		dev_dbg(&dev->dev, "SANYO scancode: 0x%06x\n", scancode);
155 		rc_keydown(dev, RC_PROTO_SANYO, scancode, 0);
156 		data->state = STATE_INACTIVE;
157 		return 0;
158 	}
159 
160 	dev_dbg(&dev->dev, "SANYO decode failed at count %d state %d (%uus %s)\n",
161 		data->count, data->state, TO_US(ev.duration), TO_STR(ev.pulse));
162 	data->state = STATE_INACTIVE;
163 	return -EINVAL;
164 }
165 
166 static const struct ir_raw_timings_pd ir_sanyo_timings = {
167 	.header_pulse  = SANYO_HEADER_PULSE,
168 	.header_space  = SANYO_HEADER_SPACE,
169 	.bit_pulse     = SANYO_BIT_PULSE,
170 	.bit_space[0]  = SANYO_BIT_0_SPACE,
171 	.bit_space[1]  = SANYO_BIT_1_SPACE,
172 	.trailer_pulse = SANYO_TRAILER_PULSE,
173 	.trailer_space = SANYO_TRAILER_SPACE,
174 	.msb_first     = 1,
175 };
176 
177 /**
178  * ir_sanyo_encode() - Encode a scancode as a stream of raw events
179  *
180  * @protocol:	protocol to encode
181  * @scancode:	scancode to encode
182  * @events:	array of raw ir events to write into
183  * @max:	maximum size of @events
184  *
185  * Returns:	The number of events written.
186  *		-ENOBUFS if there isn't enough space in the array to fit the
187  *		encoding. In this case all @max events will have been written.
188  */
189 static int ir_sanyo_encode(enum rc_proto protocol, u32 scancode,
190 			   struct ir_raw_event *events, unsigned int max)
191 {
192 	struct ir_raw_event *e = events;
193 	int ret;
194 	u64 raw;
195 
196 	raw = ((u64)(bitrev16(scancode >> 8) & 0xfff8) << (8 + 8 + 13 - 3)) |
197 	      ((u64)(bitrev16(~scancode >> 8) & 0xfff8) << (8 + 8 +  0 - 3)) |
198 	      ((bitrev8(scancode) & 0xff) << 8) |
199 	      (bitrev8(~scancode) & 0xff);
200 
201 	ret = ir_raw_gen_pd(&e, max, &ir_sanyo_timings, SANYO_NBITS, raw);
202 	if (ret < 0)
203 		return ret;
204 
205 	return e - events;
206 }
207 
208 static struct ir_raw_handler sanyo_handler = {
209 	.protocols	= RC_PROTO_BIT_SANYO,
210 	.decode		= ir_sanyo_decode,
211 	.encode		= ir_sanyo_encode,
212 	.carrier	= 38000,
213 	.min_timeout	= SANYO_TRAILER_SPACE,
214 };
215 
216 static int __init ir_sanyo_decode_init(void)
217 {
218 	ir_raw_handler_register(&sanyo_handler);
219 
220 	printk(KERN_INFO "IR SANYO protocol handler initialized\n");
221 	return 0;
222 }
223 
224 static void __exit ir_sanyo_decode_exit(void)
225 {
226 	ir_raw_handler_unregister(&sanyo_handler);
227 }
228 
229 module_init(ir_sanyo_decode_init);
230 module_exit(ir_sanyo_decode_exit);
231 
232 MODULE_LICENSE("GPL v2");
233 MODULE_AUTHOR("Mauro Carvalho Chehab");
234 MODULE_AUTHOR("Red Hat Inc. (http://www.redhat.com)");
235 MODULE_DESCRIPTION("SANYO IR protocol decoder");
236