![Mauro Carvalho Chehab](/assets/img/avatar_default.png)
The IR dprintk message that prints a RC5 decoding failure is not much helpful, as it doesn't tell on what bit the error occurred. Add such information, in order to make the debug message more useful. Signed-off-by: Mauro Carvalho Chehab <m.chehab@samsung.com>
212 lines
5.4 KiB
C
212 lines
5.4 KiB
C
/* ir-rc5-decoder.c - decoder for RC5(x) and StreamZap protocols
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*
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* Copyright (C) 2010 by Mauro Carvalho Chehab
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* Copyright (C) 2010 by Jarod Wilson <jarod@redhat.com>
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*
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* This program is free software; you can redistribute it and/or modify
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* it under the terms of the GNU General Public License as published by
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* the Free Software Foundation version 2 of the License.
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*
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* This program is distributed in the hope that it will be useful,
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* but WITHOUT ANY WARRANTY; without even the implied warranty of
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* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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* GNU General Public License for more details.
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*/
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/*
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* This decoder handles the 14 bit RC5 protocol, 15 bit "StreamZap" protocol
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* and 20 bit RC5x protocol.
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*/
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#include "rc-core-priv.h"
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#include <linux/module.h>
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#define RC5_NBITS 14
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#define RC5_SZ_NBITS 15
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#define RC5X_NBITS 20
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#define CHECK_RC5X_NBITS 8
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#define RC5_UNIT 888888 /* ns */
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#define RC5_BIT_START (1 * RC5_UNIT)
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#define RC5_BIT_END (1 * RC5_UNIT)
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#define RC5X_SPACE (4 * RC5_UNIT)
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#define RC5_TRAILER (10 * RC5_UNIT) /* In reality, approx 100 */
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enum rc5_state {
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STATE_INACTIVE,
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STATE_BIT_START,
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STATE_BIT_END,
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STATE_CHECK_RC5X,
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STATE_FINISHED,
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};
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/**
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* ir_rc5_decode() - Decode one RC-5 pulse or space
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* @dev: the struct rc_dev descriptor of the device
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* @ev: the struct ir_raw_event descriptor of the pulse/space
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*
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* This function returns -EINVAL if the pulse violates the state machine
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*/
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static int ir_rc5_decode(struct rc_dev *dev, struct ir_raw_event ev)
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{
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struct rc5_dec *data = &dev->raw->rc5;
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u8 toggle;
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u32 scancode;
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enum rc_type protocol;
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if (!(dev->enabled_protocols & (RC_BIT_RC5 | RC_BIT_RC5X)))
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return 0;
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if (!is_timing_event(ev)) {
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if (ev.reset)
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data->state = STATE_INACTIVE;
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return 0;
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}
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if (!geq_margin(ev.duration, RC5_UNIT, RC5_UNIT / 2))
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goto out;
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again:
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IR_dprintk(2, "RC5(x/sz) decode started at state %i (%uus %s)\n",
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data->state, TO_US(ev.duration), TO_STR(ev.pulse));
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if (!geq_margin(ev.duration, RC5_UNIT, RC5_UNIT / 2))
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return 0;
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switch (data->state) {
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case STATE_INACTIVE:
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if (!ev.pulse)
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break;
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data->state = STATE_BIT_START;
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data->count = 1;
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decrease_duration(&ev, RC5_BIT_START);
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goto again;
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case STATE_BIT_START:
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if (!ev.pulse && geq_margin(ev.duration, RC5_TRAILER, RC5_UNIT / 2)) {
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data->state = STATE_FINISHED;
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goto again;
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}
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if (!eq_margin(ev.duration, RC5_BIT_START, RC5_UNIT / 2))
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break;
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data->bits <<= 1;
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if (!ev.pulse)
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data->bits |= 1;
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data->count++;
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data->state = STATE_BIT_END;
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return 0;
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case STATE_BIT_END:
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if (!is_transition(&ev, &dev->raw->prev_ev))
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break;
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if (data->count == CHECK_RC5X_NBITS)
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data->state = STATE_CHECK_RC5X;
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else
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data->state = STATE_BIT_START;
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decrease_duration(&ev, RC5_BIT_END);
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goto again;
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case STATE_CHECK_RC5X:
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if (!ev.pulse && geq_margin(ev.duration, RC5X_SPACE, RC5_UNIT / 2)) {
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data->is_rc5x = true;
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decrease_duration(&ev, RC5X_SPACE);
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} else
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data->is_rc5x = false;
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data->state = STATE_BIT_START;
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goto again;
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case STATE_FINISHED:
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if (ev.pulse)
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break;
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if (data->is_rc5x && data->count == RC5X_NBITS) {
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/* RC5X */
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u8 xdata, command, system;
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if (!(dev->enabled_protocols & RC_BIT_RC5X)) {
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data->state = STATE_INACTIVE;
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return 0;
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}
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xdata = (data->bits & 0x0003F) >> 0;
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command = (data->bits & 0x00FC0) >> 6;
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system = (data->bits & 0x1F000) >> 12;
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toggle = (data->bits & 0x20000) ? 1 : 0;
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command += (data->bits & 0x01000) ? 0 : 0x40;
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scancode = system << 16 | command << 8 | xdata;
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protocol = RC_TYPE_RC5X;
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} else if (!data->is_rc5x && data->count == RC5_NBITS) {
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/* RC5 */
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u8 command, system;
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if (!(dev->enabled_protocols & RC_BIT_RC5)) {
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data->state = STATE_INACTIVE;
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return 0;
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}
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command = (data->bits & 0x0003F) >> 0;
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system = (data->bits & 0x007C0) >> 6;
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toggle = (data->bits & 0x00800) ? 1 : 0;
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command += (data->bits & 0x01000) ? 0 : 0x40;
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scancode = system << 8 | command;
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protocol = RC_TYPE_RC5;
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} else if (!data->is_rc5x && data->count == RC5_SZ_NBITS) {
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/* RC5 StreamZap */
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u8 command, system;
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if (!(dev->enabled_protocols & RC_BIT_RC5_SZ)) {
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data->state = STATE_INACTIVE;
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return 0;
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}
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command = (data->bits & 0x0003F) >> 0;
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system = (data->bits & 0x02FC0) >> 6;
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toggle = (data->bits & 0x01000) ? 1 : 0;
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scancode = system << 6 | command;
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protocol = RC_TYPE_RC5_SZ;
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} else
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break;
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IR_dprintk(1, "RC5(x/sz) scancode 0x%06x (p: %u, t: %u)\n",
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scancode, protocol, toggle);
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rc_keydown(dev, protocol, scancode, toggle);
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data->state = STATE_INACTIVE;
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return 0;
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}
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out:
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IR_dprintk(1, "RC5(x/sz) decode failed at state %i count %d (%uus %s)\n",
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data->state, data->count, TO_US(ev.duration), TO_STR(ev.pulse));
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data->state = STATE_INACTIVE;
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return -EINVAL;
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}
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static struct ir_raw_handler rc5_handler = {
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.protocols = RC_BIT_RC5 | RC_BIT_RC5X | RC_BIT_RC5_SZ,
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.decode = ir_rc5_decode,
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};
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static int __init ir_rc5_decode_init(void)
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{
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ir_raw_handler_register(&rc5_handler);
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printk(KERN_INFO "IR RC5(x/sz) protocol handler initialized\n");
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return 0;
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}
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static void __exit ir_rc5_decode_exit(void)
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{
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ir_raw_handler_unregister(&rc5_handler);
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}
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module_init(ir_rc5_decode_init);
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module_exit(ir_rc5_decode_exit);
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MODULE_LICENSE("GPL");
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MODULE_AUTHOR("Mauro Carvalho Chehab and Jarod Wilson");
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MODULE_AUTHOR("Red Hat Inc. (http://www.redhat.com)");
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MODULE_DESCRIPTION("RC5(x/sz) IR protocol decoder");
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