1 // SPDX-License-Identifier: GPL-2.0-only
2 /* ir-sony-decoder.c - handle Sony IR Pulse/Space protocol
3  *
4  * Copyright (C) 2010 by David Härdeman <david@hardeman.nu>
5  */
6 
7 #include <linux/bitrev.h>
8 #include <linux/module.h>
9 #include "rc-core-priv.h"
10 
11 #define SONY_UNIT		600 /* us */
12 #define SONY_HEADER_PULSE	(4 * SONY_UNIT)
13 #define	SONY_HEADER_SPACE	(1 * SONY_UNIT)
14 #define SONY_BIT_0_PULSE	(1 * SONY_UNIT)
15 #define SONY_BIT_1_PULSE	(2 * SONY_UNIT)
16 #define SONY_BIT_SPACE		(1 * SONY_UNIT)
17 #define SONY_TRAILER_SPACE	(10 * SONY_UNIT) /* minimum */
18 
19 enum sony_state {
20 	STATE_INACTIVE,
21 	STATE_HEADER_SPACE,
22 	STATE_BIT_PULSE,
23 	STATE_BIT_SPACE,
24 	STATE_FINISHED,
25 };
26 
27 /**
28  * ir_sony_decode() - Decode one Sony pulse or space
29  * @dev:	the struct rc_dev descriptor of the device
30  * @ev:         the struct ir_raw_event descriptor of the pulse/space
31  *
32  * This function returns -EINVAL if the pulse violates the state machine
33  */
34 static int ir_sony_decode(struct rc_dev *dev, struct ir_raw_event ev)
35 {
36 	struct sony_dec *data = &dev->raw->sony;
37 	enum rc_proto protocol;
38 	u32 scancode;
39 	u8 device, subdevice, function;
40 
41 	if (!is_timing_event(ev)) {
42 		if (ev.reset)
43 			data->state = STATE_INACTIVE;
44 		return 0;
45 	}
46 
47 	if (!geq_margin(ev.duration, SONY_UNIT, SONY_UNIT / 2))
48 		goto out;
49 
50 	dev_dbg(&dev->dev, "Sony decode started at state %d (%uus %s)\n",
51 		data->state, ev.duration, TO_STR(ev.pulse));
52 
53 	switch (data->state) {
54 
55 	case STATE_INACTIVE:
56 		if (!ev.pulse)
57 			break;
58 
59 		if (!eq_margin(ev.duration, SONY_HEADER_PULSE, SONY_UNIT / 2))
60 			break;
61 
62 		data->count = 0;
63 		data->state = STATE_HEADER_SPACE;
64 		return 0;
65 
66 	case STATE_HEADER_SPACE:
67 		if (ev.pulse)
68 			break;
69 
70 		if (!eq_margin(ev.duration, SONY_HEADER_SPACE, SONY_UNIT / 2))
71 			break;
72 
73 		data->state = STATE_BIT_PULSE;
74 		return 0;
75 
76 	case STATE_BIT_PULSE:
77 		if (!ev.pulse)
78 			break;
79 
80 		data->bits <<= 1;
81 		if (eq_margin(ev.duration, SONY_BIT_1_PULSE, SONY_UNIT / 2))
82 			data->bits |= 1;
83 		else if (!eq_margin(ev.duration, SONY_BIT_0_PULSE, SONY_UNIT / 2))
84 			break;
85 
86 		data->count++;
87 		data->state = STATE_BIT_SPACE;
88 		return 0;
89 
90 	case STATE_BIT_SPACE:
91 		if (ev.pulse)
92 			break;
93 
94 		if (!geq_margin(ev.duration, SONY_BIT_SPACE, SONY_UNIT / 2))
95 			break;
96 
97 		decrease_duration(&ev, SONY_BIT_SPACE);
98 
99 		if (!geq_margin(ev.duration, SONY_UNIT, SONY_UNIT / 2)) {
100 			data->state = STATE_BIT_PULSE;
101 			return 0;
102 		}
103 
104 		data->state = STATE_FINISHED;
105 		fallthrough;
106 
107 	case STATE_FINISHED:
108 		if (ev.pulse)
109 			break;
110 
111 		if (!geq_margin(ev.duration, SONY_TRAILER_SPACE, SONY_UNIT / 2))
112 			break;
113 
114 		switch (data->count) {
115 		case 12:
116 			if (!(dev->enabled_protocols & RC_PROTO_BIT_SONY12))
117 				goto finish_state_machine;
118 
119 			device    = bitrev8((data->bits <<  3) & 0xF8);
120 			subdevice = 0;
121 			function  = bitrev8((data->bits >>  4) & 0xFE);
122 			protocol = RC_PROTO_SONY12;
123 			break;
124 		case 15:
125 			if (!(dev->enabled_protocols & RC_PROTO_BIT_SONY15))
126 				goto finish_state_machine;
127 
128 			device    = bitrev8((data->bits >>  0) & 0xFF);
129 			subdevice = 0;
130 			function  = bitrev8((data->bits >>  7) & 0xFE);
131 			protocol = RC_PROTO_SONY15;
132 			break;
133 		case 20:
134 			if (!(dev->enabled_protocols & RC_PROTO_BIT_SONY20))
135 				goto finish_state_machine;
136 
137 			device    = bitrev8((data->bits >>  5) & 0xF8);
138 			subdevice = bitrev8((data->bits >>  0) & 0xFF);
139 			function  = bitrev8((data->bits >> 12) & 0xFE);
140 			protocol = RC_PROTO_SONY20;
141 			break;
142 		default:
143 			dev_dbg(&dev->dev, "Sony invalid bitcount %u\n",
144 				data->count);
145 			goto out;
146 		}
147 
148 		scancode = device << 16 | subdevice << 8 | function;
149 		dev_dbg(&dev->dev, "Sony(%u) scancode 0x%05x\n", data->count,
150 			scancode);
151 		rc_keydown(dev, protocol, scancode, 0);
152 		goto finish_state_machine;
153 	}
154 
155 out:
156 	dev_dbg(&dev->dev, "Sony decode failed at state %d (%uus %s)\n",
157 		data->state, ev.duration, TO_STR(ev.pulse));
158 	data->state = STATE_INACTIVE;
159 	return -EINVAL;
160 
161 finish_state_machine:
162 	data->state = STATE_INACTIVE;
163 	return 0;
164 }
165 
166 static const struct ir_raw_timings_pl ir_sony_timings = {
167 	.header_pulse  = SONY_HEADER_PULSE,
168 	.bit_space     = SONY_BIT_SPACE,
169 	.bit_pulse[0]  = SONY_BIT_0_PULSE,
170 	.bit_pulse[1]  = SONY_BIT_1_PULSE,
171 	.trailer_space = SONY_TRAILER_SPACE + SONY_BIT_SPACE,
172 	.msb_first     = 0,
173 };
174 
175 /**
176  * ir_sony_encode() - Encode a scancode as a stream of raw events
177  *
178  * @protocol:	protocol to encode
179  * @scancode:	scancode to encode
180  * @events:	array of raw ir events to write into
181  * @max:	maximum size of @events
182  *
183  * Returns:	The number of events written.
184  *		-ENOBUFS if there isn't enough space in the array to fit the
185  *		encoding. In this case all @max events will have been written.
186  */
187 static int ir_sony_encode(enum rc_proto protocol, u32 scancode,
188 			  struct ir_raw_event *events, unsigned int max)
189 {
190 	struct ir_raw_event *e = events;
191 	u32 raw, len;
192 	int ret;
193 
194 	if (protocol == RC_PROTO_SONY12) {
195 		raw = (scancode & 0x7f) | ((scancode & 0x1f0000) >> 9);
196 		len = 12;
197 	} else if (protocol == RC_PROTO_SONY15) {
198 		raw = (scancode & 0x7f) | ((scancode & 0xff0000) >> 9);
199 		len = 15;
200 	} else {
201 		raw = (scancode & 0x7f) | ((scancode & 0x1f0000) >> 9) |
202 		       ((scancode & 0xff00) << 4);
203 		len = 20;
204 	}
205 
206 	ret = ir_raw_gen_pl(&e, max, &ir_sony_timings, len, raw);
207 	if (ret < 0)
208 		return ret;
209 
210 	return e - events;
211 }
212 
213 static struct ir_raw_handler sony_handler = {
214 	.protocols	= RC_PROTO_BIT_SONY12 | RC_PROTO_BIT_SONY15 |
215 							RC_PROTO_BIT_SONY20,
216 	.decode		= ir_sony_decode,
217 	.encode		= ir_sony_encode,
218 	.carrier	= 40000,
219 	.min_timeout	= SONY_TRAILER_SPACE,
220 };
221 
222 static int __init ir_sony_decode_init(void)
223 {
224 	ir_raw_handler_register(&sony_handler);
225 
226 	printk(KERN_INFO "IR Sony protocol handler initialized\n");
227 	return 0;
228 }
229 
230 static void __exit ir_sony_decode_exit(void)
231 {
232 	ir_raw_handler_unregister(&sony_handler);
233 }
234 
235 module_init(ir_sony_decode_init);
236 module_exit(ir_sony_decode_exit);
237 
238 MODULE_LICENSE("GPL");
239 MODULE_AUTHOR("David Härdeman <david@hardeman.nu>");
240 MODULE_DESCRIPTION("Sony IR protocol decoder");
241