1 /* ir-nec-decoder.c - handle NEC IR Pulse/Space protocol
3 * Copyright (C) 2010 by Mauro Carvalho Chehab <mchehab@redhat.com>
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.
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.
15 #include <media/ir-core.h>
17 /* Start time: 4.5 ms + 560 us of the next pulse */
18 #define MIN_START_TIME (3900000 + 560000)
19 #define MAX_START_TIME (5100000 + 560000)
21 /* Bit 1 time: 2.25ms us */
22 #define MIN_BIT1_TIME 2050000
23 #define MAX_BIT1_TIME 2450000
25 /* Bit 0 time: 1.12ms us */
26 #define MIN_BIT0_TIME 920000
27 #define MAX_BIT0_TIME 1320000
29 /* Total IR code is 110 ms, including the 9 ms for the start pulse */
30 #define MAX_NEC_TIME 4000000
32 /* Total IR code is 110 ms, including the 9 ms for the start pulse */
33 #define MIN_REPEAT_TIME 99000000
34 #define MAX_REPEAT_TIME 112000000
36 /* Repeat time: 2.25ms us */
37 #define MIN_REPEAT_START_TIME 2050000
38 #define MAX_REPEAT_START_TIME 3000000
40 #define REPEAT_TIME 240 /* ms */
42 /* Used to register nec_decoder clients */
43 static LIST_HEAD(decoder_list);
44 static spinlock_t decoder_lock;
47 struct list_head list;
48 struct ir_input_dev *ir_dev;
54 * get_decoder_data() - gets decoder data
55 * @input_dev: input device
57 * Returns the struct decoder_data that corresponds to a device
60 static struct decoder_data *get_decoder_data(struct ir_input_dev *ir_dev)
62 struct decoder_data *data = NULL;
64 spin_lock(&decoder_lock);
65 list_for_each_entry(data, &decoder_list, list) {
66 if (data->ir_dev == ir_dev)
69 spin_unlock(&decoder_lock);
73 static ssize_t store_enabled(struct device *d,
74 struct device_attribute *mattr,
79 struct ir_input_dev *ir_dev = dev_get_drvdata(d);
80 struct decoder_data *data = get_decoder_data(ir_dev);
85 if (strict_strtoul(buf, 10, &value) || value > 1)
88 data->enabled = value;
93 static ssize_t show_enabled(struct device *d,
94 struct device_attribute *mattr, char *buf)
96 struct ir_input_dev *ir_dev = dev_get_drvdata(d);
97 struct decoder_data *data = get_decoder_data(ir_dev);
103 return sprintf(buf, "1\n");
105 return sprintf(buf, "0\n");
108 static DEVICE_ATTR(enabled, S_IRUGO | S_IWUSR, show_enabled, store_enabled);
110 static struct attribute *decoder_attributes[] = {
111 &dev_attr_enabled.attr,
115 static struct attribute_group decoder_attribute_group = {
116 .name = "nec_decoder",
117 .attrs = decoder_attributes,
121 /** is_repeat - Check if it is a NEC repeat event
122 * @input_dev: the struct input_dev descriptor of the device
123 * @pos: the position of the first event
124 * @len: the length of the buffer
126 static int is_repeat(struct ir_raw_event *evs, int len, int pos)
128 if ((evs[pos].delta.tv_nsec < MIN_REPEAT_START_TIME) ||
129 (evs[pos].delta.tv_nsec > MAX_REPEAT_START_TIME))
135 if ((evs[pos].delta.tv_nsec < MIN_REPEAT_TIME) ||
136 (evs[pos].delta.tv_nsec > MAX_REPEAT_TIME))
143 * __ir_nec_decode() - Decode one NEC pulsecode
144 * @input_dev: the struct input_dev descriptor of the device
145 * @evs: event array with type/duration of pulse/space
146 * @len: length of the array
147 * @pos: position to start seeking for a code
148 * This function returns -EINVAL if no pulse got decoded,
149 * 0 if buffer is empty and 1 if one keycode were handled.
151 static int __ir_nec_decode(struct input_dev *input_dev,
152 struct ir_raw_event *evs,
155 struct ir_input_dev *ir = input_get_drvdata(input_dev);
157 int ircode = 0, not_code = 0;
159 /* Be sure that the first event is an start one and is a pulse */
160 for (; *pos < len; (*pos)++) {
161 /* Very long delays are considered as start events */
162 if (evs[*pos].delta.tv_nsec > MAX_NEC_TIME)
164 if (evs[*pos].type & IR_START_EVENT)
166 IR_dprintk(1, "%luus: Spurious NEC %s\n",
167 (evs[*pos].delta.tv_nsec + 500) / 1000,
168 (evs[*pos].type & IR_SPACE) ? "space" : "pulse");
174 (*pos)++; /* First event doesn't contain data */
176 if (evs[*pos].type != IR_PULSE)
179 /* Check if it is a NEC repeat event */
180 if (is_repeat(evs, len, *pos)) {
182 if (ir->keypressed) {
183 ir_repeat(input_dev);
184 IR_dprintk(1, "NEC repeat event\n");
187 IR_dprintk(1, "missing NEC repeat event\n");
192 /* First space should have 4.5 ms otherwise is not NEC protocol */
193 if ((evs[*pos].delta.tv_nsec < MIN_START_TIME) ||
194 (evs[*pos].delta.tv_nsec > MAX_START_TIME))
198 for ((*pos)++; *pos < len; (*pos)++) {
200 if ((evs[*pos].delta.tv_nsec > MIN_BIT1_TIME) &&
201 (evs[*pos].delta.tv_nsec < MAX_BIT1_TIME))
203 else if ((evs[*pos].delta.tv_nsec > MIN_BIT0_TIME) &&
204 (evs[*pos].delta.tv_nsec < MAX_BIT0_TIME))
211 /* Address first, then command */
214 ircode |= 1 << shift;
215 } else if (shift < 16) {
216 not_code |= 1 << shift;
217 } else if (shift < 24) {
219 ircode |= 1 << shift;
222 not_code |= 1 << shift;
231 * Fixme: may need to accept Extended NEC protocol?
233 if ((ircode & ~not_code) != ircode) {
234 IR_dprintk(1, "NEC checksum error: code 0x%04x, not-code 0x%04x\n",
239 IR_dprintk(1, "NEC scancode 0x%04x\n", ircode);
240 ir_keydown(input_dev, ircode, 0);
244 IR_dprintk(1, "NEC decoded failed at bit %d (%s) while decoding %luus time\n",
246 (evs[*pos].type & IR_SPACE) ? "space" : "pulse",
247 (evs[*pos].delta.tv_nsec + 500) / 1000);
253 * __ir_nec_decode() - Decodes all NEC pulsecodes on a given array
254 * @input_dev: the struct input_dev descriptor of the device
255 * @evs: event array with type/duration of pulse/space
256 * @len: length of the array
257 * This function returns the number of decoded pulses
259 static int ir_nec_decode(struct input_dev *input_dev,
260 struct ir_raw_event *evs,
263 struct ir_input_dev *ir_dev = input_get_drvdata(input_dev);
264 struct decoder_data *data;
268 data = get_decoder_data(ir_dev);
269 if (!data || !data->enabled)
273 if (__ir_nec_decode(input_dev, evs, len, &pos) > 0)
279 static int ir_nec_register(struct input_dev *input_dev)
281 struct ir_input_dev *ir_dev = input_get_drvdata(input_dev);
282 struct decoder_data *data;
285 rc = sysfs_create_group(&ir_dev->dev.kobj, &decoder_attribute_group);
289 data = kzalloc(sizeof(*data), GFP_KERNEL);
291 sysfs_remove_group(&ir_dev->dev.kobj, &decoder_attribute_group);
295 data->ir_dev = ir_dev;
298 spin_lock(&decoder_lock);
299 list_add_tail(&data->list, &decoder_list);
300 spin_unlock(&decoder_lock);
305 static int ir_nec_unregister(struct input_dev *input_dev)
307 struct ir_input_dev *ir_dev = input_get_drvdata(input_dev);
308 static struct decoder_data *data;
310 data = get_decoder_data(ir_dev);
314 sysfs_remove_group(&ir_dev->dev.kobj, &decoder_attribute_group);
316 spin_lock(&decoder_lock);
317 list_del(&data->list);
318 spin_unlock(&decoder_lock);
323 static struct ir_raw_handler nec_handler = {
324 .decode = ir_nec_decode,
325 .raw_register = ir_nec_register,
326 .raw_unregister = ir_nec_unregister,
329 static int __init ir_nec_decode_init(void)
331 ir_raw_handler_register(&nec_handler);
333 printk(KERN_INFO "IR NEC protocol handler initialized\n");
337 static void __exit ir_nec_decode_exit(void)
339 ir_raw_handler_unregister(&nec_handler);
342 module_init(ir_nec_decode_init);
343 module_exit(ir_nec_decode_exit);
345 MODULE_LICENSE("GPL");
346 MODULE_AUTHOR("Mauro Carvalho Chehab <mchehab@redhat.com>");
347 MODULE_AUTHOR("Red Hat Inc. (http://www.redhat.com)");
348 MODULE_DESCRIPTION("NEC IR protocol decoder");