Commit | Line | Data |
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995187be | 1 | /* ir-nec-decoder.c - handle NEC IR Pulse/Space protocol |
a3572c34 MCC |
2 | * |
3 | * Copyright (C) 2010 by Mauro Carvalho Chehab <mchehab@redhat.com> | |
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 <media/ir-core.h> | |
16 | ||
67780d6a | 17 | #define NEC_NBITS 32 |
2f16f631 MCC |
18 | #define NEC_UNIT 559979 /* ns */ |
19 | #define NEC_HEADER_MARK (16 * NEC_UNIT) | |
20 | #define NEC_HEADER_SPACE (8 * NEC_UNIT) | |
21 | #define NEC_REPEAT_SPACE (4 * NEC_UNIT) | |
22 | #define NEC_MARK (NEC_UNIT) | |
67780d6a MCC |
23 | #define NEC_0_SPACE (NEC_UNIT) |
24 | #define NEC_1_SPACE (3 * NEC_UNIT) | |
9f154782 | 25 | |
20d5f116 MCC |
26 | /* Used to register nec_decoder clients */ |
27 | static LIST_HEAD(decoder_list); | |
28 | static spinlock_t decoder_lock; | |
29 | ||
2f16f631 MCC |
30 | enum nec_state { |
31 | STATE_INACTIVE, | |
32 | STATE_HEADER_MARK, | |
33 | STATE_HEADER_SPACE, | |
34 | STATE_MARK, | |
35 | STATE_SPACE, | |
36 | STATE_TRAILER_MARK, | |
37 | STATE_TRAILER_SPACE, | |
38 | }; | |
39 | ||
40 | struct nec_code { | |
41 | u8 address; | |
42 | u8 not_address; | |
43 | u8 command; | |
44 | u8 not_command; | |
45 | }; | |
46 | ||
20d5f116 MCC |
47 | struct decoder_data { |
48 | struct list_head list; | |
49 | struct ir_input_dev *ir_dev; | |
50 | int enabled:1; | |
2f16f631 MCC |
51 | |
52 | /* State machine control */ | |
53 | enum nec_state state; | |
54 | struct nec_code nec_code; | |
55 | unsigned count; | |
20d5f116 MCC |
56 | }; |
57 | ||
58 | ||
59 | /** | |
60 | * get_decoder_data() - gets decoder data | |
61 | * @input_dev: input device | |
62 | * | |
63 | * Returns the struct decoder_data that corresponds to a device | |
64 | */ | |
65 | ||
66 | static struct decoder_data *get_decoder_data(struct ir_input_dev *ir_dev) | |
67 | { | |
68 | struct decoder_data *data = NULL; | |
69 | ||
70 | spin_lock(&decoder_lock); | |
71 | list_for_each_entry(data, &decoder_list, list) { | |
72 | if (data->ir_dev == ir_dev) | |
73 | break; | |
74 | } | |
75 | spin_unlock(&decoder_lock); | |
76 | return data; | |
77 | } | |
78 | ||
79 | static ssize_t store_enabled(struct device *d, | |
80 | struct device_attribute *mattr, | |
81 | const char *buf, | |
82 | size_t len) | |
83 | { | |
84 | unsigned long value; | |
85 | struct ir_input_dev *ir_dev = dev_get_drvdata(d); | |
86 | struct decoder_data *data = get_decoder_data(ir_dev); | |
87 | ||
88 | if (!data) | |
89 | return -EINVAL; | |
90 | ||
91 | if (strict_strtoul(buf, 10, &value) || value > 1) | |
92 | return -EINVAL; | |
93 | ||
94 | data->enabled = value; | |
95 | ||
96 | return len; | |
97 | } | |
98 | ||
99 | static ssize_t show_enabled(struct device *d, | |
100 | struct device_attribute *mattr, char *buf) | |
101 | { | |
102 | struct ir_input_dev *ir_dev = dev_get_drvdata(d); | |
103 | struct decoder_data *data = get_decoder_data(ir_dev); | |
104 | ||
105 | if (!data) | |
106 | return -EINVAL; | |
107 | ||
108 | if (data->enabled) | |
109 | return sprintf(buf, "1\n"); | |
110 | else | |
111 | return sprintf(buf, "0\n"); | |
112 | } | |
113 | ||
114 | static DEVICE_ATTR(enabled, S_IRUGO | S_IWUSR, show_enabled, store_enabled); | |
115 | ||
116 | static struct attribute *decoder_attributes[] = { | |
117 | &dev_attr_enabled.attr, | |
118 | NULL | |
119 | }; | |
120 | ||
121 | static struct attribute_group decoder_attribute_group = { | |
122 | .name = "nec_decoder", | |
123 | .attrs = decoder_attributes, | |
124 | }; | |
125 | ||
126 | ||
2f16f631 | 127 | /** |
587835a4 | 128 | * ir_nec_decode() - Decode one NEC pulse or space |
9f154782 | 129 | * @input_dev: the struct input_dev descriptor of the device |
2f16f631 MCC |
130 | * @ev: event array with type/duration of pulse/space |
131 | * | |
132 | * This function returns -EINVAL if the pulse violates the state machine | |
9f154782 | 133 | */ |
587835a4 MCC |
134 | static int ir_nec_decode(struct input_dev *input_dev, |
135 | struct ir_raw_event *ev) | |
9f154782 | 136 | { |
2f16f631 MCC |
137 | struct decoder_data *data; |
138 | struct ir_input_dev *ir_dev = input_get_drvdata(input_dev); | |
139 | int bit, last_bit; | |
9f154782 | 140 | |
2f16f631 MCC |
141 | data = get_decoder_data(ir_dev); |
142 | if (!data) | |
143 | return -EINVAL; | |
9f154782 | 144 | |
2f16f631 MCC |
145 | /* Except for the initial event, what matters is the previous bit */ |
146 | bit = (ev->type & IR_PULSE) ? 1 : 0; | |
9f154782 | 147 | |
2f16f631 | 148 | last_bit = !bit; |
a3572c34 | 149 | |
2f16f631 | 150 | /* Discards spurious space last_bits when inactive */ |
a3572c34 | 151 | |
2f16f631 MCC |
152 | /* Very long delays are considered as start events */ |
153 | if (ev->delta.tv_nsec > NEC_HEADER_MARK + NEC_HEADER_SPACE - NEC_UNIT / 2) | |
154 | data->state = STATE_INACTIVE; | |
a3572c34 | 155 | |
2f16f631 MCC |
156 | if (ev->type & IR_START_EVENT) |
157 | data->state = STATE_INACTIVE; | |
9f154782 | 158 | |
2f16f631 MCC |
159 | switch (data->state) { |
160 | case STATE_INACTIVE: | |
161 | if (!bit) /* PULSE marks the start event */ | |
162 | return 0; | |
a3572c34 | 163 | |
2f16f631 MCC |
164 | data->count = 0; |
165 | data->state = STATE_HEADER_MARK; | |
166 | memset (&data->nec_code, 0, sizeof(data->nec_code)); | |
167 | return 0; | |
168 | case STATE_HEADER_MARK: | |
169 | if (!last_bit) | |
170 | goto err; | |
171 | if (ev->delta.tv_nsec < NEC_HEADER_MARK - 6 * NEC_UNIT) | |
172 | goto err; | |
173 | data->state = STATE_HEADER_SPACE; | |
174 | return 0; | |
175 | case STATE_HEADER_SPACE: | |
176 | if (last_bit) | |
177 | goto err; | |
178 | if (ev->delta.tv_nsec >= NEC_HEADER_SPACE - NEC_UNIT / 2) { | |
179 | data->state = STATE_MARK; | |
9f154782 MCC |
180 | return 0; |
181 | } | |
9f154782 | 182 | |
2f16f631 MCC |
183 | if (ev->delta.tv_nsec >= NEC_REPEAT_SPACE - NEC_UNIT / 2) { |
184 | ir_repeat(input_dev); | |
185 | IR_dprintk(1, "Repeat last key\n"); | |
186 | data->state = STATE_TRAILER_MARK; | |
187 | return 0; | |
188 | } | |
9f154782 | 189 | goto err; |
2f16f631 MCC |
190 | case STATE_MARK: |
191 | if (!last_bit) | |
192 | goto err; | |
193 | if ((ev->delta.tv_nsec > NEC_MARK + NEC_UNIT / 2) || | |
194 | (ev->delta.tv_nsec < NEC_MARK - NEC_UNIT / 2)) | |
195 | goto err; | |
196 | data->state = STATE_SPACE; | |
197 | return 0; | |
198 | case STATE_SPACE: | |
199 | if (last_bit) | |
200 | goto err; | |
a3572c34 | 201 | |
67780d6a MCC |
202 | if ((ev->delta.tv_nsec >= NEC_0_SPACE - NEC_UNIT / 2) && |
203 | (ev->delta.tv_nsec < NEC_0_SPACE + NEC_UNIT / 2)) | |
a3572c34 | 204 | bit = 0; |
67780d6a MCC |
205 | else if ((ev->delta.tv_nsec >= NEC_1_SPACE - NEC_UNIT / 2) && |
206 | (ev->delta.tv_nsec < NEC_1_SPACE + NEC_UNIT / 2)) | |
2f16f631 MCC |
207 | bit = 1; |
208 | else { | |
209 | IR_dprintk(1, "Decode failed at %d-th bit (%s) @%luus\n", | |
210 | data->count, | |
211 | last_bit ? "pulse" : "space", | |
212 | (ev->delta.tv_nsec + 500) / 1000); | |
213 | ||
214 | goto err2; | |
215 | } | |
a3572c34 | 216 | |
2f16f631 | 217 | /* Ok, we've got a valid bit. proccess it */ |
a3572c34 | 218 | if (bit) { |
2f16f631 MCC |
219 | int shift = data->count; |
220 | ||
221 | /* | |
222 | * NEC transmit bytes on this temporal order: | |
223 | * address | not address | command | not command | |
224 | */ | |
a3572c34 | 225 | if (shift < 8) { |
2f16f631 | 226 | data->nec_code.address |= 1 << shift; |
a3572c34 | 227 | } else if (shift < 16) { |
2f16f631 | 228 | data->nec_code.not_address |= 1 << (shift - 8); |
a3572c34 | 229 | } else if (shift < 24) { |
2f16f631 | 230 | data->nec_code.command |= 1 << (shift - 16); |
a3572c34 | 231 | } else { |
2f16f631 | 232 | data->nec_code.not_command |= 1 << (shift - 24); |
a3572c34 MCC |
233 | } |
234 | } | |
67780d6a | 235 | if (++data->count == NEC_NBITS) { |
2f16f631 MCC |
236 | u32 scancode; |
237 | /* | |
238 | * Fixme: may need to accept Extended NEC protocol? | |
239 | */ | |
240 | if ((data->nec_code.command ^ data->nec_code.not_command) != 0xff) | |
241 | goto checksum_err; | |
242 | ||
243 | if ((data->nec_code.address ^ data->nec_code.not_address) != 0xff) { | |
244 | /* Extended NEC */ | |
245 | scancode = data->nec_code.address << 16 | | |
246 | data->nec_code.not_address << 8 | | |
247 | data->nec_code.command; | |
248 | IR_dprintk(1, "NEC scancode 0x%06x\n", scancode); | |
249 | } else { | |
250 | /* normal NEC */ | |
251 | scancode = data->nec_code.address << 8 | | |
252 | data->nec_code.command; | |
253 | IR_dprintk(1, "NEC scancode 0x%04x\n", scancode); | |
254 | } | |
255 | ir_keydown(input_dev, scancode, 0); | |
a3572c34 | 256 | |
2f16f631 MCC |
257 | data->state = STATE_TRAILER_MARK; |
258 | } else | |
259 | data->state = STATE_MARK; | |
260 | return 0; | |
261 | case STATE_TRAILER_MARK: | |
262 | if (!last_bit) | |
263 | goto err; | |
264 | data->state = STATE_TRAILER_SPACE; | |
265 | return 0; | |
266 | case STATE_TRAILER_SPACE: | |
267 | if (last_bit) | |
268 | goto err; | |
269 | data->state = STATE_INACTIVE; | |
270 | return 0; | |
271 | } | |
a3572c34 | 272 | |
a3572c34 | 273 | err: |
2f16f631 MCC |
274 | IR_dprintk(1, "NEC decoded failed at state %d (%s) @ %luus\n", |
275 | data->state, | |
276 | bit ? "pulse" : "space", | |
277 | (ev->delta.tv_nsec + 500) / 1000); | |
278 | err2: | |
279 | data->state = STATE_INACTIVE; | |
280 | return -EINVAL; | |
a3572c34 | 281 | |
2f16f631 MCC |
282 | checksum_err: |
283 | data->state = STATE_INACTIVE; | |
284 | IR_dprintk(1, "NEC checksum error: received 0x%02x%02x%02x%02x\n", | |
285 | data->nec_code.address, | |
286 | data->nec_code.not_address, | |
287 | data->nec_code.command, | |
288 | data->nec_code.not_command); | |
a3572c34 MCC |
289 | return -EINVAL; |
290 | } | |
ada39630 | 291 | |
20d5f116 MCC |
292 | static int ir_nec_register(struct input_dev *input_dev) |
293 | { | |
294 | struct ir_input_dev *ir_dev = input_get_drvdata(input_dev); | |
295 | struct decoder_data *data; | |
296 | int rc; | |
297 | ||
298 | rc = sysfs_create_group(&ir_dev->dev.kobj, &decoder_attribute_group); | |
299 | if (rc < 0) | |
300 | return rc; | |
301 | ||
302 | data = kzalloc(sizeof(*data), GFP_KERNEL); | |
303 | if (!data) { | |
304 | sysfs_remove_group(&ir_dev->dev.kobj, &decoder_attribute_group); | |
305 | return -ENOMEM; | |
306 | } | |
307 | ||
308 | data->ir_dev = ir_dev; | |
309 | data->enabled = 1; | |
310 | ||
311 | spin_lock(&decoder_lock); | |
312 | list_add_tail(&data->list, &decoder_list); | |
313 | spin_unlock(&decoder_lock); | |
314 | ||
315 | return 0; | |
316 | } | |
317 | ||
318 | static int ir_nec_unregister(struct input_dev *input_dev) | |
319 | { | |
320 | struct ir_input_dev *ir_dev = input_get_drvdata(input_dev); | |
321 | static struct decoder_data *data; | |
322 | ||
323 | data = get_decoder_data(ir_dev); | |
324 | if (!data) | |
325 | return 0; | |
326 | ||
327 | sysfs_remove_group(&ir_dev->dev.kobj, &decoder_attribute_group); | |
328 | ||
329 | spin_lock(&decoder_lock); | |
330 | list_del(&data->list); | |
331 | spin_unlock(&decoder_lock); | |
332 | ||
333 | return 0; | |
334 | } | |
335 | ||
995187be | 336 | static struct ir_raw_handler nec_handler = { |
20d5f116 MCC |
337 | .decode = ir_nec_decode, |
338 | .raw_register = ir_nec_register, | |
339 | .raw_unregister = ir_nec_unregister, | |
995187be MCC |
340 | }; |
341 | ||
342 | static int __init ir_nec_decode_init(void) | |
343 | { | |
344 | ir_raw_handler_register(&nec_handler); | |
345 | ||
346 | printk(KERN_INFO "IR NEC protocol handler initialized\n"); | |
347 | return 0; | |
348 | } | |
349 | ||
350 | static void __exit ir_nec_decode_exit(void) | |
351 | { | |
352 | ir_raw_handler_unregister(&nec_handler); | |
353 | } | |
354 | ||
355 | module_init(ir_nec_decode_init); | |
356 | module_exit(ir_nec_decode_exit); | |
357 | ||
358 | MODULE_LICENSE("GPL"); | |
359 | MODULE_AUTHOR("Mauro Carvalho Chehab <mchehab@redhat.com>"); | |
360 | MODULE_AUTHOR("Red Hat Inc. (http://www.redhat.com)"); | |
361 | MODULE_DESCRIPTION("NEC IR protocol decoder"); |