mirror of https://gitee.com/openkylin/linux.git
199 lines
5.0 KiB
C
199 lines
5.0 KiB
C
/* ir-rc5-decoder.c - handle RC5(x) IR Pulse/Space protocol
|
|
*
|
|
* Copyright (C) 2010 by Mauro Carvalho Chehab <mchehab@redhat.com>
|
|
*
|
|
* This program is free software; you can redistribute it and/or modify
|
|
* it under the terms of the GNU General Public License as published by
|
|
* the Free Software Foundation version 2 of the License.
|
|
*
|
|
* This program is distributed in the hope that it will be useful,
|
|
* but WITHOUT ANY WARRANTY; without even the implied warranty of
|
|
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
|
|
* GNU General Public License for more details.
|
|
*/
|
|
|
|
/*
|
|
* This code handles 14 bits RC5 protocols and 20 bits RC5x protocols.
|
|
* There are other variants that use a different number of bits.
|
|
* This is currently unsupported.
|
|
* It considers a carrier of 36 kHz, with a total of 14/20 bits, where
|
|
* the first two bits are start bits, and a third one is a filing bit
|
|
*/
|
|
|
|
#include "rc-core-priv.h"
|
|
#include <linux/module.h>
|
|
|
|
#define RC5_NBITS 14
|
|
#define RC5X_NBITS 20
|
|
#define CHECK_RC5X_NBITS 8
|
|
#define RC5_UNIT 888888 /* ns */
|
|
#define RC5_BIT_START (1 * RC5_UNIT)
|
|
#define RC5_BIT_END (1 * RC5_UNIT)
|
|
#define RC5X_SPACE (4 * RC5_UNIT)
|
|
|
|
enum rc5_state {
|
|
STATE_INACTIVE,
|
|
STATE_BIT_START,
|
|
STATE_BIT_END,
|
|
STATE_CHECK_RC5X,
|
|
STATE_FINISHED,
|
|
};
|
|
|
|
/**
|
|
* ir_rc5_decode() - Decode one RC-5 pulse or space
|
|
* @dev: the struct rc_dev descriptor of the device
|
|
* @ev: the struct ir_raw_event descriptor of the pulse/space
|
|
*
|
|
* This function returns -EINVAL if the pulse violates the state machine
|
|
*/
|
|
static int ir_rc5_decode(struct rc_dev *dev, struct ir_raw_event ev)
|
|
{
|
|
struct rc5_dec *data = &dev->raw->rc5;
|
|
u8 toggle;
|
|
u32 scancode;
|
|
|
|
if (!(dev->enabled_protocols & (RC_BIT_RC5 | RC_BIT_RC5X)))
|
|
return 0;
|
|
|
|
if (!is_timing_event(ev)) {
|
|
if (ev.reset)
|
|
data->state = STATE_INACTIVE;
|
|
return 0;
|
|
}
|
|
|
|
if (!geq_margin(ev.duration, RC5_UNIT, RC5_UNIT / 2))
|
|
goto out;
|
|
|
|
again:
|
|
IR_dprintk(2, "RC5(x) decode started at state %i (%uus %s)\n",
|
|
data->state, TO_US(ev.duration), TO_STR(ev.pulse));
|
|
|
|
if (!geq_margin(ev.duration, RC5_UNIT, RC5_UNIT / 2))
|
|
return 0;
|
|
|
|
switch (data->state) {
|
|
|
|
case STATE_INACTIVE:
|
|
if (!ev.pulse)
|
|
break;
|
|
|
|
data->state = STATE_BIT_START;
|
|
data->count = 1;
|
|
/* We just need enough bits to get to STATE_CHECK_RC5X */
|
|
data->wanted_bits = RC5X_NBITS;
|
|
decrease_duration(&ev, RC5_BIT_START);
|
|
goto again;
|
|
|
|
case STATE_BIT_START:
|
|
if (!eq_margin(ev.duration, RC5_BIT_START, RC5_UNIT / 2))
|
|
break;
|
|
|
|
data->bits <<= 1;
|
|
if (!ev.pulse)
|
|
data->bits |= 1;
|
|
data->count++;
|
|
data->state = STATE_BIT_END;
|
|
return 0;
|
|
|
|
case STATE_BIT_END:
|
|
if (!is_transition(&ev, &dev->raw->prev_ev))
|
|
break;
|
|
|
|
if (data->count == data->wanted_bits)
|
|
data->state = STATE_FINISHED;
|
|
else if (data->count == CHECK_RC5X_NBITS)
|
|
data->state = STATE_CHECK_RC5X;
|
|
else
|
|
data->state = STATE_BIT_START;
|
|
|
|
decrease_duration(&ev, RC5_BIT_END);
|
|
goto again;
|
|
|
|
case STATE_CHECK_RC5X:
|
|
if (!ev.pulse && geq_margin(ev.duration, RC5X_SPACE, RC5_UNIT / 2)) {
|
|
/* RC5X */
|
|
data->wanted_bits = RC5X_NBITS;
|
|
decrease_duration(&ev, RC5X_SPACE);
|
|
} else {
|
|
/* RC5 */
|
|
data->wanted_bits = RC5_NBITS;
|
|
}
|
|
data->state = STATE_BIT_START;
|
|
goto again;
|
|
|
|
case STATE_FINISHED:
|
|
if (ev.pulse)
|
|
break;
|
|
|
|
if (data->wanted_bits == RC5X_NBITS) {
|
|
/* RC5X */
|
|
u8 xdata, command, system;
|
|
if (!(dev->enabled_protocols & RC_BIT_RC5X)) {
|
|
data->state = STATE_INACTIVE;
|
|
return 0;
|
|
}
|
|
xdata = (data->bits & 0x0003F) >> 0;
|
|
command = (data->bits & 0x00FC0) >> 6;
|
|
system = (data->bits & 0x1F000) >> 12;
|
|
toggle = (data->bits & 0x20000) ? 1 : 0;
|
|
command += (data->bits & 0x01000) ? 0 : 0x40;
|
|
scancode = system << 16 | command << 8 | xdata;
|
|
|
|
IR_dprintk(1, "RC5X scancode 0x%06x (toggle: %u)\n",
|
|
scancode, toggle);
|
|
|
|
} else {
|
|
/* RC5 */
|
|
u8 command, system;
|
|
if (!(dev->enabled_protocols & RC_BIT_RC5)) {
|
|
data->state = STATE_INACTIVE;
|
|
return 0;
|
|
}
|
|
command = (data->bits & 0x0003F) >> 0;
|
|
system = (data->bits & 0x007C0) >> 6;
|
|
toggle = (data->bits & 0x00800) ? 1 : 0;
|
|
command += (data->bits & 0x01000) ? 0 : 0x40;
|
|
scancode = system << 8 | command;
|
|
|
|
IR_dprintk(1, "RC5 scancode 0x%04x (toggle: %u)\n",
|
|
scancode, toggle);
|
|
}
|
|
|
|
rc_keydown(dev, scancode, toggle);
|
|
data->state = STATE_INACTIVE;
|
|
return 0;
|
|
}
|
|
|
|
out:
|
|
IR_dprintk(1, "RC5(x) decode failed at state %i (%uus %s)\n",
|
|
data->state, TO_US(ev.duration), TO_STR(ev.pulse));
|
|
data->state = STATE_INACTIVE;
|
|
return -EINVAL;
|
|
}
|
|
|
|
static struct ir_raw_handler rc5_handler = {
|
|
.protocols = RC_BIT_RC5 | RC_BIT_RC5X,
|
|
.decode = ir_rc5_decode,
|
|
};
|
|
|
|
static int __init ir_rc5_decode_init(void)
|
|
{
|
|
ir_raw_handler_register(&rc5_handler);
|
|
|
|
printk(KERN_INFO "IR RC5(x) protocol handler initialized\n");
|
|
return 0;
|
|
}
|
|
|
|
static void __exit ir_rc5_decode_exit(void)
|
|
{
|
|
ir_raw_handler_unregister(&rc5_handler);
|
|
}
|
|
|
|
module_init(ir_rc5_decode_init);
|
|
module_exit(ir_rc5_decode_exit);
|
|
|
|
MODULE_LICENSE("GPL");
|
|
MODULE_AUTHOR("Mauro Carvalho Chehab <mchehab@redhat.com>");
|
|
MODULE_AUTHOR("Red Hat Inc. (http://www.redhat.com)");
|
|
MODULE_DESCRIPTION("RC5(x) IR protocol decoder");
|