1 /* ir-rc5-decoder.c - decoder for RC5(x) and StreamZap protocols
3 * Copyright (C) 2010 by Mauro Carvalho Chehab
4 * Copyright (C) 2010 by Jarod Wilson <jarod@redhat.com>
6 * This program is free software; you can redistribute it and/or modify
7 * it under the terms of the GNU General Public License as published by
8 * the Free Software Foundation version 2 of the License.
10 * This program is distributed in the hope that it will be useful,
11 * but WITHOUT ANY WARRANTY; without even the implied warranty of
12 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
13 * GNU General Public License for more details.
17 * This decoder handles the 14 bit RC5 protocol, 15 bit "StreamZap" protocol
18 * and 20 bit RC5x protocol.
21 #include "rc-core-priv.h"
22 #include <linux/module.h>
25 #define RC5_SZ_NBITS 15
27 #define CHECK_RC5X_NBITS 8
28 #define RC5_UNIT 888888 /* ns */
29 #define RC5_BIT_START (1 * RC5_UNIT)
30 #define RC5_BIT_END (1 * RC5_UNIT)
31 #define RC5X_SPACE (4 * RC5_UNIT)
32 #define RC5_TRAILER (6 * RC5_UNIT) /* In reality, approx 100 */
43 * ir_rc5_decode() - Decode one RC-5 pulse or space
44 * @dev: the struct rc_dev descriptor of the device
45 * @ev: the struct ir_raw_event descriptor of the pulse/space
47 * This function returns -EINVAL if the pulse violates the state machine
49 static int ir_rc5_decode(struct rc_dev *dev, struct ir_raw_event ev)
51 struct rc5_dec *data = &dev->raw->rc5;
54 enum rc_type protocol;
56 if (!is_timing_event(ev)) {
58 data->state = STATE_INACTIVE;
62 if (!geq_margin(ev.duration, RC5_UNIT, RC5_UNIT / 2))
66 IR_dprintk(2, "RC5(x/sz) decode started at state %i (%uus %s)\n",
67 data->state, TO_US(ev.duration), TO_STR(ev.pulse));
69 if (!geq_margin(ev.duration, RC5_UNIT, RC5_UNIT / 2))
72 switch (data->state) {
78 data->state = STATE_BIT_START;
80 decrease_duration(&ev, RC5_BIT_START);
84 if (!ev.pulse && geq_margin(ev.duration, RC5_TRAILER, RC5_UNIT / 2)) {
85 data->state = STATE_FINISHED;
89 if (!eq_margin(ev.duration, RC5_BIT_START, RC5_UNIT / 2))
96 data->state = STATE_BIT_END;
100 if (!is_transition(&ev, &dev->raw->prev_ev))
103 if (data->count == CHECK_RC5X_NBITS)
104 data->state = STATE_CHECK_RC5X;
106 data->state = STATE_BIT_START;
108 decrease_duration(&ev, RC5_BIT_END);
111 case STATE_CHECK_RC5X:
112 if (!ev.pulse && geq_margin(ev.duration, RC5X_SPACE, RC5_UNIT / 2)) {
113 data->is_rc5x = true;
114 decrease_duration(&ev, RC5X_SPACE);
116 data->is_rc5x = false;
117 data->state = STATE_BIT_START;
124 if (data->is_rc5x && data->count == RC5X_NBITS) {
126 u8 xdata, command, system;
127 if (!(dev->enabled_protocols & RC_BIT_RC5X)) {
128 data->state = STATE_INACTIVE;
131 xdata = (data->bits & 0x0003F) >> 0;
132 command = (data->bits & 0x00FC0) >> 6;
133 system = (data->bits & 0x1F000) >> 12;
134 toggle = (data->bits & 0x20000) ? 1 : 0;
135 command += (data->bits & 0x01000) ? 0 : 0x40;
136 scancode = system << 16 | command << 8 | xdata;
137 protocol = RC_TYPE_RC5X;
139 } else if (!data->is_rc5x && data->count == RC5_NBITS) {
142 if (!(dev->enabled_protocols & RC_BIT_RC5)) {
143 data->state = STATE_INACTIVE;
146 command = (data->bits & 0x0003F) >> 0;
147 system = (data->bits & 0x007C0) >> 6;
148 toggle = (data->bits & 0x00800) ? 1 : 0;
149 command += (data->bits & 0x01000) ? 0 : 0x40;
150 scancode = system << 8 | command;
151 protocol = RC_TYPE_RC5;
153 } else if (!data->is_rc5x && data->count == RC5_SZ_NBITS) {
156 if (!(dev->enabled_protocols & RC_BIT_RC5_SZ)) {
157 data->state = STATE_INACTIVE;
160 command = (data->bits & 0x0003F) >> 0;
161 system = (data->bits & 0x02FC0) >> 6;
162 toggle = (data->bits & 0x01000) ? 1 : 0;
163 scancode = system << 6 | command;
164 protocol = RC_TYPE_RC5_SZ;
169 IR_dprintk(1, "RC5(x/sz) scancode 0x%06x (p: %u, t: %u)\n",
170 scancode, protocol, toggle);
172 rc_keydown(dev, protocol, scancode, toggle);
173 data->state = STATE_INACTIVE;
178 IR_dprintk(1, "RC5(x/sz) decode failed at state %i count %d (%uus %s)\n",
179 data->state, data->count, TO_US(ev.duration), TO_STR(ev.pulse));
180 data->state = STATE_INACTIVE;
184 static struct ir_raw_handler rc5_handler = {
185 .protocols = RC_BIT_RC5 | RC_BIT_RC5X | RC_BIT_RC5_SZ,
186 .decode = ir_rc5_decode,
189 static int __init ir_rc5_decode_init(void)
191 ir_raw_handler_register(&rc5_handler);
193 printk(KERN_INFO "IR RC5(x/sz) protocol handler initialized\n");
197 static void __exit ir_rc5_decode_exit(void)
199 ir_raw_handler_unregister(&rc5_handler);
202 module_init(ir_rc5_decode_init);
203 module_exit(ir_rc5_decode_exit);
205 MODULE_LICENSE("GPL");
206 MODULE_AUTHOR("Mauro Carvalho Chehab and Jarod Wilson");
207 MODULE_AUTHOR("Red Hat Inc. (http://www.redhat.com)");
208 MODULE_DESCRIPTION("RC5(x/sz) IR protocol decoder");