1 /* ir-rc5-sz-decoder.c - handle RC5 Streamzap IR Pulse/Space protocol
3 * Copyright (C) 2010 by Mauro Carvalho Chehab <mchehab@redhat.com>
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 code handles the 15 bit RC5-ish protocol used by the Streamzap
19 * It considers a carrier of 36 kHz, with a total of 15 bits, where
20 * the first two bits are start bits, and a third one is a filing bit
23 #include "rc-core-priv.h"
24 #include <linux/module.h>
26 #define RC5_SZ_NBITS 15
27 #define RC5_UNIT 888888 /* ns */
28 #define RC5_BIT_START (1 * RC5_UNIT)
29 #define RC5_BIT_END (1 * RC5_UNIT)
39 * ir_rc5_sz_decode() - Decode one RC-5 Streamzap pulse or space
40 * @dev: the struct rc_dev descriptor of the device
41 * @ev: the struct ir_raw_event descriptor of the pulse/space
43 * This function returns -EINVAL if the pulse violates the state machine
45 static int ir_rc5_sz_decode(struct rc_dev *dev, struct ir_raw_event ev)
47 struct rc5_sz_dec *data = &dev->raw->rc5_sz;
48 u8 toggle, command, system;
51 if (!(dev->raw->enabled_protocols & RC_TYPE_RC5_SZ))
54 if (!is_timing_event(ev)) {
56 data->state = STATE_INACTIVE;
60 if (!geq_margin(ev.duration, RC5_UNIT, RC5_UNIT / 2))
64 IR_dprintk(2, "RC5-sz decode started at state %i (%uus %s)\n",
65 data->state, TO_US(ev.duration), TO_STR(ev.pulse));
67 if (!geq_margin(ev.duration, RC5_UNIT, RC5_UNIT / 2))
70 switch (data->state) {
76 data->state = STATE_BIT_START;
78 data->wanted_bits = RC5_SZ_NBITS;
79 decrease_duration(&ev, RC5_BIT_START);
83 if (!eq_margin(ev.duration, RC5_BIT_START, RC5_UNIT / 2))
90 data->state = STATE_BIT_END;
94 if (!is_transition(&ev, &dev->raw->prev_ev))
97 if (data->count == data->wanted_bits)
98 data->state = STATE_FINISHED;
100 data->state = STATE_BIT_START;
102 decrease_duration(&ev, RC5_BIT_END);
110 command = (data->bits & 0x0003F) >> 0;
111 system = (data->bits & 0x02FC0) >> 6;
112 toggle = (data->bits & 0x01000) ? 1 : 0;
113 scancode = system << 6 | command;
115 IR_dprintk(1, "RC5-sz scancode 0x%04x (toggle: %u)\n",
118 rc_keydown(dev, scancode, toggle);
119 data->state = STATE_INACTIVE;
124 IR_dprintk(1, "RC5-sz decode failed at state %i (%uus %s)\n",
125 data->state, TO_US(ev.duration), TO_STR(ev.pulse));
126 data->state = STATE_INACTIVE;
130 static struct ir_raw_handler rc5_sz_handler = {
131 .protocols = RC_TYPE_RC5_SZ,
132 .decode = ir_rc5_sz_decode,
135 static int __init ir_rc5_sz_decode_init(void)
137 ir_raw_handler_register(&rc5_sz_handler);
139 printk(KERN_INFO "IR RC5 (streamzap) protocol handler initialized\n");
143 static void __exit ir_rc5_sz_decode_exit(void)
145 ir_raw_handler_unregister(&rc5_sz_handler);
148 module_init(ir_rc5_sz_decode_init);
149 module_exit(ir_rc5_sz_decode_exit);
151 MODULE_LICENSE("GPL");
152 MODULE_AUTHOR("Jarod Wilson <jarod@redhat.com>");
153 MODULE_AUTHOR("Red Hat Inc. (http://www.redhat.com)");
154 MODULE_DESCRIPTION("RC5 (streamzap) IR protocol decoder");