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David Härdeman733419b2010-04-08 20:04:30 -03001/* ir-rc5-decoder.c - handle RC5(x) IR Pulse/Space protocol
Mauro Carvalho Chehabdb1423a2010-04-04 10:27:20 -03002 *
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/*
David Härdeman733419b2010-04-08 20:04:30 -030016 * This code handles 14 bits RC5 protocols and 20 bits RC5x protocols.
17 * There are other variants that use a different number of bits.
18 * This is currently unsupported.
19 * It considers a carrier of 36 kHz, with a total of 14/20 bits, where
Mauro Carvalho Chehab9b09df52010-04-06 02:29:42 -030020 * the first two bits are start bits, and a third one is a filing bit
Mauro Carvalho Chehabdb1423a2010-04-04 10:27:20 -030021 */
22
Mauro Carvalho Chehab3f113e32010-04-08 15:10:27 -030023#include "ir-core-priv.h"
Mauro Carvalho Chehabdb1423a2010-04-04 10:27:20 -030024
25#define RC5_NBITS 14
David Härdeman733419b2010-04-08 20:04:30 -030026#define RC5X_NBITS 20
27#define CHECK_RC5X_NBITS 8
David Härdeman724e2492010-04-08 13:10:00 -030028#define RC5_UNIT 888888 /* ns */
David Härdemane40b1122010-04-15 18:46:00 -030029#define RC5_BIT_START (1 * RC5_UNIT)
30#define RC5_BIT_END (1 * RC5_UNIT)
31#define RC5X_SPACE (4 * RC5_UNIT)
Mauro Carvalho Chehabdb1423a2010-04-04 10:27:20 -030032
33/* Used to register rc5_decoder clients */
34static LIST_HEAD(decoder_list);
Mauro Carvalho Chehab6eb94352010-04-07 16:19:36 -030035static DEFINE_SPINLOCK(decoder_lock);
Mauro Carvalho Chehabdb1423a2010-04-04 10:27:20 -030036
37enum rc5_state {
38 STATE_INACTIVE,
David Härdeman724e2492010-04-08 13:10:00 -030039 STATE_BIT_START,
40 STATE_BIT_END,
David Härdeman733419b2010-04-08 20:04:30 -030041 STATE_CHECK_RC5X,
David Härdeman724e2492010-04-08 13:10:00 -030042 STATE_FINISHED,
Mauro Carvalho Chehabdb1423a2010-04-04 10:27:20 -030043};
44
45struct decoder_data {
46 struct list_head list;
47 struct ir_input_dev *ir_dev;
Mauro Carvalho Chehabdb1423a2010-04-04 10:27:20 -030048
49 /* State machine control */
50 enum rc5_state state;
David Härdeman724e2492010-04-08 13:10:00 -030051 u32 rc5_bits;
David Härdemane40b1122010-04-15 18:46:00 -030052 struct ir_raw_event prev_ev;
David Härdeman724e2492010-04-08 13:10:00 -030053 unsigned count;
David Härdeman733419b2010-04-08 20:04:30 -030054 unsigned wanted_bits;
Mauro Carvalho Chehabdb1423a2010-04-04 10:27:20 -030055};
56
57
58/**
59 * get_decoder_data() - gets decoder data
60 * @input_dev: input device
61 *
62 * Returns the struct decoder_data that corresponds to a device
63 */
64
65static struct decoder_data *get_decoder_data(struct ir_input_dev *ir_dev)
66{
67 struct decoder_data *data = NULL;
68
69 spin_lock(&decoder_lock);
70 list_for_each_entry(data, &decoder_list, list) {
71 if (data->ir_dev == ir_dev)
72 break;
73 }
74 spin_unlock(&decoder_lock);
75 return data;
76}
77
Mauro Carvalho Chehabdb1423a2010-04-04 10:27:20 -030078/**
David Härdeman724e2492010-04-08 13:10:00 -030079 * ir_rc5_decode() - Decode one RC-5 pulse or space
Mauro Carvalho Chehabdb1423a2010-04-04 10:27:20 -030080 * @input_dev: the struct input_dev descriptor of the device
David Härdemane40b1122010-04-15 18:46:00 -030081 * @ev: the struct ir_raw_event descriptor of the pulse/space
Mauro Carvalho Chehabdb1423a2010-04-04 10:27:20 -030082 *
83 * This function returns -EINVAL if the pulse violates the state machine
84 */
David Härdemane40b1122010-04-15 18:46:00 -030085static int ir_rc5_decode(struct input_dev *input_dev, struct ir_raw_event ev)
Mauro Carvalho Chehabdb1423a2010-04-04 10:27:20 -030086{
87 struct decoder_data *data;
88 struct ir_input_dev *ir_dev = input_get_drvdata(input_dev);
David Härdeman733419b2010-04-08 20:04:30 -030089 u8 toggle;
David Härdeman724e2492010-04-08 13:10:00 -030090 u32 scancode;
Mauro Carvalho Chehabdb1423a2010-04-04 10:27:20 -030091
92 data = get_decoder_data(ir_dev);
93 if (!data)
94 return -EINVAL;
95
David Härdeman667c9eb2010-06-13 17:29:31 -030096 if (!(ir_dev->raw->enabled_protocols & IR_TYPE_RC5))
97 return 0;
Mauro Carvalho Chehab7f20d322010-04-04 14:45:04 -030098
David Härdemane40b1122010-04-15 18:46:00 -030099 if (IS_RESET(ev)) {
Mauro Carvalho Chehabdb1423a2010-04-04 10:27:20 -0300100 data->state = STATE_INACTIVE;
101 return 0;
102 }
103
David Härdemane40b1122010-04-15 18:46:00 -0300104 if (!geq_margin(ev.duration, RC5_UNIT, RC5_UNIT / 2))
David Härdeman724e2492010-04-08 13:10:00 -0300105 goto out;
106
107again:
David Härdemane40b1122010-04-15 18:46:00 -0300108 IR_dprintk(2, "RC5(x) decode started at state %i (%uus %s)\n",
109 data->state, TO_US(ev.duration), TO_STR(ev.pulse));
David Härdeman724e2492010-04-08 13:10:00 -0300110
David Härdemane40b1122010-04-15 18:46:00 -0300111 if (!geq_margin(ev.duration, RC5_UNIT, RC5_UNIT / 2))
David Härdeman724e2492010-04-08 13:10:00 -0300112 return 0;
113
114 switch (data->state) {
115
116 case STATE_INACTIVE:
David Härdemane40b1122010-04-15 18:46:00 -0300117 if (!ev.pulse)
118 break;
119
120 data->state = STATE_BIT_START;
121 data->count = 1;
122 /* We just need enough bits to get to STATE_CHECK_RC5X */
123 data->wanted_bits = RC5X_NBITS;
124 decrease_duration(&ev, RC5_BIT_START);
125 goto again;
David Härdeman724e2492010-04-08 13:10:00 -0300126
127 case STATE_BIT_START:
David Härdemane40b1122010-04-15 18:46:00 -0300128 if (!eq_margin(ev.duration, RC5_BIT_START, RC5_UNIT / 2))
129 break;
David Härdeman724e2492010-04-08 13:10:00 -0300130
David Härdemane40b1122010-04-15 18:46:00 -0300131 data->rc5_bits <<= 1;
132 if (!ev.pulse)
133 data->rc5_bits |= 1;
134 data->count++;
135 data->prev_ev = ev;
136 data->state = STATE_BIT_END;
137 return 0;
David Härdeman724e2492010-04-08 13:10:00 -0300138
139 case STATE_BIT_END:
David Härdemane40b1122010-04-15 18:46:00 -0300140 if (!is_transition(&ev, &data->prev_ev))
141 break;
David Härdeman724e2492010-04-08 13:10:00 -0300142
David Härdemane40b1122010-04-15 18:46:00 -0300143 if (data->count == data->wanted_bits)
144 data->state = STATE_FINISHED;
145 else if (data->count == CHECK_RC5X_NBITS)
146 data->state = STATE_CHECK_RC5X;
147 else
148 data->state = STATE_BIT_START;
149
150 decrease_duration(&ev, RC5_BIT_END);
151 goto again;
David Härdeman724e2492010-04-08 13:10:00 -0300152
David Härdeman733419b2010-04-08 20:04:30 -0300153 case STATE_CHECK_RC5X:
David Härdemane40b1122010-04-15 18:46:00 -0300154 if (!ev.pulse && geq_margin(ev.duration, RC5X_SPACE, RC5_UNIT / 2)) {
David Härdeman733419b2010-04-08 20:04:30 -0300155 /* RC5X */
156 data->wanted_bits = RC5X_NBITS;
David Härdemane40b1122010-04-15 18:46:00 -0300157 decrease_duration(&ev, RC5X_SPACE);
David Härdeman733419b2010-04-08 20:04:30 -0300158 } else {
159 /* RC5 */
160 data->wanted_bits = RC5_NBITS;
161 }
162 data->state = STATE_BIT_START;
163 goto again;
David Härdeman724e2492010-04-08 13:10:00 -0300164
David Härdeman733419b2010-04-08 20:04:30 -0300165 case STATE_FINISHED:
David Härdemane40b1122010-04-15 18:46:00 -0300166 if (ev.pulse)
167 break;
168
David Härdeman733419b2010-04-08 20:04:30 -0300169 if (data->wanted_bits == RC5X_NBITS) {
170 /* RC5X */
171 u8 xdata, command, system;
172 xdata = (data->rc5_bits & 0x0003F) >> 0;
173 command = (data->rc5_bits & 0x00FC0) >> 6;
174 system = (data->rc5_bits & 0x1F000) >> 12;
175 toggle = (data->rc5_bits & 0x20000) ? 1 : 0;
176 command += (data->rc5_bits & 0x01000) ? 0 : 0x40;
177 scancode = system << 16 | command << 8 | xdata;
178
179 IR_dprintk(1, "RC5X scancode 0x%06x (toggle: %u)\n",
180 scancode, toggle);
181
182 } else {
183 /* RC5 */
184 u8 command, system;
185 command = (data->rc5_bits & 0x0003F) >> 0;
186 system = (data->rc5_bits & 0x007C0) >> 6;
187 toggle = (data->rc5_bits & 0x00800) ? 1 : 0;
188 command += (data->rc5_bits & 0x01000) ? 0 : 0x40;
189 scancode = system << 8 | command;
190
191 IR_dprintk(1, "RC5 scancode 0x%04x (toggle: %u)\n",
192 scancode, toggle);
193 }
194
David Härdeman724e2492010-04-08 13:10:00 -0300195 ir_keydown(input_dev, scancode, toggle);
196 data->state = STATE_INACTIVE;
197 return 0;
198 }
199
200out:
David Härdemane40b1122010-04-15 18:46:00 -0300201 IR_dprintk(1, "RC5(x) decode failed at state %i (%uus %s)\n",
202 data->state, TO_US(ev.duration), TO_STR(ev.pulse));
Mauro Carvalho Chehabdb1423a2010-04-04 10:27:20 -0300203 data->state = STATE_INACTIVE;
204 return -EINVAL;
205}
206
Mauro Carvalho Chehabdb1423a2010-04-04 10:27:20 -0300207static int ir_rc5_register(struct input_dev *input_dev)
208{
209 struct ir_input_dev *ir_dev = input_get_drvdata(input_dev);
210 struct decoder_data *data;
Mauro Carvalho Chehabdb1423a2010-04-04 10:27:20 -0300211
212 data = kzalloc(sizeof(*data), GFP_KERNEL);
David Härdeman667c9eb2010-06-13 17:29:31 -0300213 if (!data)
Mauro Carvalho Chehabdb1423a2010-04-04 10:27:20 -0300214 return -ENOMEM;
Mauro Carvalho Chehabdb1423a2010-04-04 10:27:20 -0300215
216 data->ir_dev = ir_dev;
Mauro Carvalho Chehabdb1423a2010-04-04 10:27:20 -0300217
218 spin_lock(&decoder_lock);
219 list_add_tail(&data->list, &decoder_list);
220 spin_unlock(&decoder_lock);
221
222 return 0;
223}
224
225static int ir_rc5_unregister(struct input_dev *input_dev)
226{
227 struct ir_input_dev *ir_dev = input_get_drvdata(input_dev);
228 static struct decoder_data *data;
229
230 data = get_decoder_data(ir_dev);
231 if (!data)
232 return 0;
233
Mauro Carvalho Chehabdb1423a2010-04-04 10:27:20 -0300234 spin_lock(&decoder_lock);
235 list_del(&data->list);
236 spin_unlock(&decoder_lock);
237
238 return 0;
239}
240
241static struct ir_raw_handler rc5_handler = {
David Härdeman667c9eb2010-06-13 17:29:31 -0300242 .protocols = IR_TYPE_RC5,
Mauro Carvalho Chehabdb1423a2010-04-04 10:27:20 -0300243 .decode = ir_rc5_decode,
244 .raw_register = ir_rc5_register,
245 .raw_unregister = ir_rc5_unregister,
246};
247
248static int __init ir_rc5_decode_init(void)
249{
250 ir_raw_handler_register(&rc5_handler);
251
David Härdeman733419b2010-04-08 20:04:30 -0300252 printk(KERN_INFO "IR RC5(x) protocol handler initialized\n");
Mauro Carvalho Chehabdb1423a2010-04-04 10:27:20 -0300253 return 0;
254}
255
256static void __exit ir_rc5_decode_exit(void)
257{
258 ir_raw_handler_unregister(&rc5_handler);
259}
260
261module_init(ir_rc5_decode_init);
262module_exit(ir_rc5_decode_exit);
263
264MODULE_LICENSE("GPL");
265MODULE_AUTHOR("Mauro Carvalho Chehab <mchehab@redhat.com>");
266MODULE_AUTHOR("Red Hat Inc. (http://www.redhat.com)");
David Härdeman733419b2010-04-08 20:04:30 -0300267MODULE_DESCRIPTION("RC5(x) IR protocol decoder");