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995187be | 1 | /* ir-nec-decoder.c - handle NEC IR Pulse/Space protocol |
a3572c34 | 2 | * |
37e59f87 | 3 | * Copyright (C) 2010 by Mauro Carvalho Chehab |
a3572c34 MCC |
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 | ||
724e2495 | 15 | #include <linux/bitrev.h> |
7a707b89 | 16 | #include <linux/module.h> |
f62de675 | 17 | #include "rc-core-priv.h" |
a3572c34 | 18 | |
67780d6a | 19 | #define NEC_NBITS 32 |
724e2495 | 20 | #define NEC_UNIT 562500 /* ns */ |
e40b1127 DH |
21 | #define NEC_HEADER_PULSE (16 * NEC_UNIT) |
22 | #define NECX_HEADER_PULSE (8 * NEC_UNIT) /* Less common NEC variant */ | |
23 | #define NEC_HEADER_SPACE (8 * NEC_UNIT) | |
e31f4127 | 24 | #define NEC_REPEAT_SPACE (4 * NEC_UNIT) |
e40b1127 DH |
25 | #define NEC_BIT_PULSE (1 * NEC_UNIT) |
26 | #define NEC_BIT_0_SPACE (1 * NEC_UNIT) | |
27 | #define NEC_BIT_1_SPACE (3 * NEC_UNIT) | |
28 | #define NEC_TRAILER_PULSE (1 * NEC_UNIT) | |
29 | #define NEC_TRAILER_SPACE (10 * NEC_UNIT) /* even longer in reality */ | |
86ff071c | 30 | #define NECX_REPEAT_BITS 1 |
9f154782 | 31 | |
2f16f631 MCC |
32 | enum nec_state { |
33 | STATE_INACTIVE, | |
2f16f631 | 34 | STATE_HEADER_SPACE, |
724e2495 DH |
35 | STATE_BIT_PULSE, |
36 | STATE_BIT_SPACE, | |
37 | STATE_TRAILER_PULSE, | |
2f16f631 MCC |
38 | STATE_TRAILER_SPACE, |
39 | }; | |
40 | ||
2f16f631 | 41 | /** |
587835a4 | 42 | * ir_nec_decode() - Decode one NEC pulse or space |
d8b4b582 | 43 | * @dev: the struct rc_dev descriptor of the device |
64dc6829 | 44 | * @ev: the struct ir_raw_event descriptor of the pulse/space |
2f16f631 MCC |
45 | * |
46 | * This function returns -EINVAL if the pulse violates the state machine | |
9f154782 | 47 | */ |
d8b4b582 | 48 | static int ir_nec_decode(struct rc_dev *dev, struct ir_raw_event ev) |
9f154782 | 49 | { |
d8b4b582 | 50 | struct nec_dec *data = &dev->raw->nec; |
724e2495 | 51 | u32 scancode; |
6d741bfe | 52 | enum rc_proto rc_proto; |
724e2495 | 53 | u8 address, not_address, command, not_command; |
9f154782 | 54 | |
4651918a ML |
55 | if (!is_timing_event(ev)) { |
56 | if (ev.reset) | |
57 | data->state = STATE_INACTIVE; | |
724e2495 DH |
58 | return 0; |
59 | } | |
a3572c34 | 60 | |
e40b1127 DH |
61 | IR_dprintk(2, "NEC decode started at state %d (%uus %s)\n", |
62 | data->state, TO_US(ev.duration), TO_STR(ev.pulse)); | |
9f154782 | 63 | |
2f16f631 | 64 | switch (data->state) { |
a3572c34 | 65 | |
724e2495 | 66 | case STATE_INACTIVE: |
e40b1127 DH |
67 | if (!ev.pulse) |
68 | break; | |
69 | ||
743135e7 | 70 | if (eq_margin(ev.duration, NEC_HEADER_PULSE, NEC_UNIT * 2)) { |
86ff071c ML |
71 | data->is_nec_x = false; |
72 | data->necx_repeat = false; | |
73 | } else if (eq_margin(ev.duration, NECX_HEADER_PULSE, NEC_UNIT / 2)) | |
74 | data->is_nec_x = true; | |
75 | else | |
e40b1127 DH |
76 | break; |
77 | ||
78 | data->count = 0; | |
79 | data->state = STATE_HEADER_SPACE; | |
2f16f631 | 80 | return 0; |
724e2495 | 81 | |
2f16f631 | 82 | case STATE_HEADER_SPACE: |
e40b1127 DH |
83 | if (ev.pulse) |
84 | break; | |
85 | ||
743135e7 | 86 | if (eq_margin(ev.duration, NEC_HEADER_SPACE, NEC_UNIT)) { |
724e2495 | 87 | data->state = STATE_BIT_PULSE; |
9f154782 | 88 | return 0; |
e40b1127 | 89 | } else if (eq_margin(ev.duration, NEC_REPEAT_SPACE, NEC_UNIT / 2)) { |
265a2988 | 90 | data->state = STATE_TRAILER_PULSE; |
2f16f631 MCC |
91 | return 0; |
92 | } | |
e40b1127 | 93 | |
724e2495 DH |
94 | break; |
95 | ||
96 | case STATE_BIT_PULSE: | |
e40b1127 DH |
97 | if (!ev.pulse) |
98 | break; | |
99 | ||
100 | if (!eq_margin(ev.duration, NEC_BIT_PULSE, NEC_UNIT / 2)) | |
101 | break; | |
102 | ||
103 | data->state = STATE_BIT_SPACE; | |
104 | return 0; | |
724e2495 DH |
105 | |
106 | case STATE_BIT_SPACE: | |
e40b1127 | 107 | if (ev.pulse) |
724e2495 DH |
108 | break; |
109 | ||
86ff071c ML |
110 | if (data->necx_repeat && data->count == NECX_REPEAT_BITS && |
111 | geq_margin(ev.duration, | |
112 | NEC_TRAILER_SPACE, NEC_UNIT / 2)) { | |
113 | IR_dprintk(1, "Repeat last key\n"); | |
ca86674b | 114 | rc_repeat(dev); |
86ff071c ML |
115 | data->state = STATE_INACTIVE; |
116 | return 0; | |
117 | ||
118 | } else if (data->count > NECX_REPEAT_BITS) | |
119 | data->necx_repeat = false; | |
120 | ||
c216369e | 121 | data->bits <<= 1; |
e40b1127 | 122 | if (eq_margin(ev.duration, NEC_BIT_1_SPACE, NEC_UNIT / 2)) |
c216369e | 123 | data->bits |= 1; |
e40b1127 DH |
124 | else if (!eq_margin(ev.duration, NEC_BIT_0_SPACE, NEC_UNIT / 2)) |
125 | break; | |
724e2495 DH |
126 | data->count++; |
127 | ||
e40b1127 DH |
128 | if (data->count == NEC_NBITS) |
129 | data->state = STATE_TRAILER_PULSE; | |
130 | else | |
724e2495 | 131 | data->state = STATE_BIT_PULSE; |
e40b1127 DH |
132 | |
133 | return 0; | |
134 | ||
135 | case STATE_TRAILER_PULSE: | |
136 | if (!ev.pulse) | |
137 | break; | |
138 | ||
139 | if (!eq_margin(ev.duration, NEC_TRAILER_PULSE, NEC_UNIT / 2)) | |
140 | break; | |
141 | ||
142 | data->state = STATE_TRAILER_SPACE; | |
143 | return 0; | |
144 | ||
145 | case STATE_TRAILER_SPACE: | |
146 | if (ev.pulse) | |
147 | break; | |
148 | ||
149 | if (!geq_margin(ev.duration, NEC_TRAILER_SPACE, NEC_UNIT / 2)) | |
150 | break; | |
724e2495 | 151 | |
829bbf26 SY |
152 | if (data->count == NEC_NBITS) { |
153 | address = bitrev8((data->bits >> 24) & 0xff); | |
154 | not_address = bitrev8((data->bits >> 16) & 0xff); | |
155 | command = bitrev8((data->bits >> 8) & 0xff); | |
156 | not_command = bitrev8((data->bits >> 0) & 0xff); | |
157 | ||
158 | scancode = ir_nec_bytes_to_scancode(address, | |
159 | not_address, | |
160 | command, | |
161 | not_command, | |
162 | &rc_proto); | |
724e2495 | 163 | |
829bbf26 SY |
164 | if (data->is_nec_x) |
165 | data->necx_repeat = true; | |
724e2495 | 166 | |
829bbf26 SY |
167 | rc_keydown(dev, rc_proto, scancode, 0); |
168 | } else { | |
169 | rc_repeat(dev); | |
170 | } | |
86ff071c | 171 | |
e40b1127 | 172 | data->state = STATE_INACTIVE; |
2f16f631 | 173 | return 0; |
724e2495 | 174 | } |
a3572c34 | 175 | |
39cac375 MCC |
176 | IR_dprintk(1, "NEC decode failed at count %d state %d (%uus %s)\n", |
177 | data->count, data->state, TO_US(ev.duration), TO_STR(ev.pulse)); | |
2f16f631 | 178 | data->state = STATE_INACTIVE; |
a3572c34 MCC |
179 | return -EINVAL; |
180 | } | |
ada39630 | 181 | |
141cfb14 JH |
182 | /** |
183 | * ir_nec_scancode_to_raw() - encode an NEC scancode ready for modulation. | |
184 | * @protocol: specific protocol to use | |
185 | * @scancode: a single NEC scancode. | |
141cfb14 | 186 | */ |
6d741bfe | 187 | static u32 ir_nec_scancode_to_raw(enum rc_proto protocol, u32 scancode) |
141cfb14 JH |
188 | { |
189 | unsigned int addr, addr_inv, data, data_inv; | |
190 | ||
191 | data = scancode & 0xff; | |
192 | ||
6d741bfe | 193 | if (protocol == RC_PROTO_NEC32) { |
141cfb14 JH |
194 | /* 32-bit NEC (used by Apple and TiVo remotes) */ |
195 | /* scan encoding: aaAAddDD */ | |
196 | addr_inv = (scancode >> 24) & 0xff; | |
197 | addr = (scancode >> 16) & 0xff; | |
198 | data_inv = (scancode >> 8) & 0xff; | |
6d741bfe | 199 | } else if (protocol == RC_PROTO_NECX) { |
141cfb14 JH |
200 | /* Extended NEC */ |
201 | /* scan encoding AAaaDD */ | |
202 | addr = (scancode >> 16) & 0xff; | |
203 | addr_inv = (scancode >> 8) & 0xff; | |
204 | data_inv = data ^ 0xff; | |
205 | } else { | |
206 | /* Normal NEC */ | |
207 | /* scan encoding: AADD */ | |
208 | addr = (scancode >> 8) & 0xff; | |
209 | addr_inv = addr ^ 0xff; | |
210 | data_inv = data ^ 0xff; | |
211 | } | |
212 | ||
213 | /* raw encoding: ddDDaaAA */ | |
214 | return data_inv << 24 | | |
215 | data << 16 | | |
216 | addr_inv << 8 | | |
217 | addr; | |
218 | } | |
219 | ||
220 | static const struct ir_raw_timings_pd ir_nec_timings = { | |
221 | .header_pulse = NEC_HEADER_PULSE, | |
222 | .header_space = NEC_HEADER_SPACE, | |
223 | .bit_pulse = NEC_BIT_PULSE, | |
224 | .bit_space[0] = NEC_BIT_0_SPACE, | |
225 | .bit_space[1] = NEC_BIT_1_SPACE, | |
226 | .trailer_pulse = NEC_TRAILER_PULSE, | |
227 | .trailer_space = NEC_TRAILER_SPACE, | |
228 | .msb_first = 0, | |
229 | }; | |
230 | ||
231 | /** | |
232 | * ir_nec_encode() - Encode a scancode as a stream of raw events | |
233 | * | |
234 | * @protocol: protocol to encode | |
235 | * @scancode: scancode to encode | |
236 | * @events: array of raw ir events to write into | |
237 | * @max: maximum size of @events | |
238 | * | |
239 | * Returns: The number of events written. | |
240 | * -ENOBUFS if there isn't enough space in the array to fit the | |
241 | * encoding. In this case all @max events will have been written. | |
242 | */ | |
6d741bfe | 243 | static int ir_nec_encode(enum rc_proto protocol, u32 scancode, |
141cfb14 JH |
244 | struct ir_raw_event *events, unsigned int max) |
245 | { | |
246 | struct ir_raw_event *e = events; | |
247 | int ret; | |
248 | u32 raw; | |
249 | ||
250 | /* Convert a NEC scancode to raw NEC data */ | |
251 | raw = ir_nec_scancode_to_raw(protocol, scancode); | |
252 | ||
253 | /* Modulate the raw data using a pulse distance modulation */ | |
254 | ret = ir_raw_gen_pd(&e, max, &ir_nec_timings, NEC_NBITS, raw); | |
255 | if (ret < 0) | |
256 | return ret; | |
257 | ||
258 | return e - events; | |
259 | } | |
260 | ||
995187be | 261 | static struct ir_raw_handler nec_handler = { |
6d741bfe SY |
262 | .protocols = RC_PROTO_BIT_NEC | RC_PROTO_BIT_NECX | |
263 | RC_PROTO_BIT_NEC32, | |
20d5f116 | 264 | .decode = ir_nec_decode, |
141cfb14 | 265 | .encode = ir_nec_encode, |
995187be MCC |
266 | }; |
267 | ||
268 | static int __init ir_nec_decode_init(void) | |
269 | { | |
270 | ir_raw_handler_register(&nec_handler); | |
271 | ||
272 | printk(KERN_INFO "IR NEC protocol handler initialized\n"); | |
273 | return 0; | |
274 | } | |
275 | ||
276 | static void __exit ir_nec_decode_exit(void) | |
277 | { | |
278 | ir_raw_handler_unregister(&nec_handler); | |
279 | } | |
280 | ||
281 | module_init(ir_nec_decode_init); | |
282 | module_exit(ir_nec_decode_exit); | |
283 | ||
284 | MODULE_LICENSE("GPL"); | |
37e59f87 | 285 | MODULE_AUTHOR("Mauro Carvalho Chehab"); |
995187be MCC |
286 | MODULE_AUTHOR("Red Hat Inc. (http://www.redhat.com)"); |
287 | MODULE_DESCRIPTION("NEC IR protocol decoder"); |