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This patch to the IR RC6 decoder adds support for variable length mode-6A frames which can range in size from 8 to 128 bits. Please refer to the following link for a detailed explanation or RC6 frames: http://slydiman.narod.ru/scr/kb/rc6.htm This change removes the assumption that frames are fixed length (currently either 24 or 32 data bits) and actually counts the number of bits until an end of frame marker is seen. [mchehab@redhat.com: Tested with a RC-6(0) IR - 16 bits] Tested-by: Mauro Carvalho Chehab <mchehab@redhat.com> Signed-off-by: Mauro Carvalho Chehab <mchehab@redhat.com>
297 lines
7.1 KiB
C
297 lines
7.1 KiB
C
/* ir-rc6-decoder.c - A decoder for the RC6 IR protocol
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*
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* Copyright (C) 2010 by David Härdeman <david@hardeman.nu>
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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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#include "rc-core-priv.h"
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#include <linux/module.h>
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/*
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* This decoder currently supports:
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* RC6-0-16 (standard toggle bit in header)
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* RC6-6A-20 (no toggle bit)
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* RC6-6A-24 (no toggle bit)
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* RC6-6A-32 (MCE version with toggle bit in body)
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*/
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#define RC6_UNIT 444444 /* nanosecs */
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#define RC6_HEADER_NBITS 4 /* not including toggle bit */
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#define RC6_0_NBITS 16
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#define RC6_6A_32_NBITS 32
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#define RC6_6A_NBITS 128 /* Variable 8..128 */
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#define RC6_PREFIX_PULSE (6 * RC6_UNIT)
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#define RC6_PREFIX_SPACE (2 * RC6_UNIT)
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#define RC6_BIT_START (1 * RC6_UNIT)
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#define RC6_BIT_END (1 * RC6_UNIT)
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#define RC6_TOGGLE_START (2 * RC6_UNIT)
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#define RC6_TOGGLE_END (2 * RC6_UNIT)
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#define RC6_SUFFIX_SPACE (6 * RC6_UNIT)
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#define RC6_MODE_MASK 0x07 /* for the header bits */
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#define RC6_STARTBIT_MASK 0x08 /* for the header bits */
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#define RC6_6A_MCE_TOGGLE_MASK 0x8000 /* for the body bits */
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#define RC6_6A_LCC_MASK 0xffff0000 /* RC6-6A-32 long customer code mask */
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#define RC6_6A_MCE_CC 0x800f0000 /* MCE customer code */
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#ifndef CHAR_BIT
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#define CHAR_BIT 8 /* Normally in <limits.h> */
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#endif
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enum rc6_mode {
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RC6_MODE_0,
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RC6_MODE_6A,
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RC6_MODE_UNKNOWN,
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};
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enum rc6_state {
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STATE_INACTIVE,
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STATE_PREFIX_SPACE,
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STATE_HEADER_BIT_START,
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STATE_HEADER_BIT_END,
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STATE_TOGGLE_START,
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STATE_TOGGLE_END,
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STATE_BODY_BIT_START,
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STATE_BODY_BIT_END,
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STATE_FINISHED,
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};
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static enum rc6_mode rc6_mode(struct rc6_dec *data)
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{
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switch (data->header & RC6_MODE_MASK) {
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case 0:
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return RC6_MODE_0;
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case 6:
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if (!data->toggle)
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return RC6_MODE_6A;
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/* fall through */
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default:
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return RC6_MODE_UNKNOWN;
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}
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}
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/**
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* ir_rc6_decode() - Decode one RC6 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_rc6_decode(struct rc_dev *dev, struct ir_raw_event ev)
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{
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struct rc6_dec *data = &dev->raw->rc6;
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u32 scancode;
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u8 toggle;
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if (!(dev->raw->enabled_protocols & RC_TYPE_RC6))
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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, RC6_UNIT, RC6_UNIT / 2))
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goto out;
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again:
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IR_dprintk(2, "RC6 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, RC6_UNIT, RC6_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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/* Note: larger margin on first pulse since each RC6_UNIT
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is quite short and some hardware takes some time to
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adjust to the signal */
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if (!eq_margin(ev.duration, RC6_PREFIX_PULSE, RC6_UNIT))
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break;
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data->state = STATE_PREFIX_SPACE;
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data->count = 0;
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return 0;
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case STATE_PREFIX_SPACE:
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if (ev.pulse)
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break;
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if (!eq_margin(ev.duration, RC6_PREFIX_SPACE, RC6_UNIT / 2))
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break;
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data->state = STATE_HEADER_BIT_START;
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data->header = 0;
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return 0;
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case STATE_HEADER_BIT_START:
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if (!eq_margin(ev.duration, RC6_BIT_START, RC6_UNIT / 2))
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break;
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data->header <<= 1;
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if (ev.pulse)
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data->header |= 1;
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data->count++;
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data->state = STATE_HEADER_BIT_END;
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return 0;
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case STATE_HEADER_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 == RC6_HEADER_NBITS)
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data->state = STATE_TOGGLE_START;
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else
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data->state = STATE_HEADER_BIT_START;
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decrease_duration(&ev, RC6_BIT_END);
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goto again;
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case STATE_TOGGLE_START:
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if (!eq_margin(ev.duration, RC6_TOGGLE_START, RC6_UNIT / 2))
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break;
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data->toggle = ev.pulse;
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data->state = STATE_TOGGLE_END;
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return 0;
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case STATE_TOGGLE_END:
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if (!is_transition(&ev, &dev->raw->prev_ev) ||
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!geq_margin(ev.duration, RC6_TOGGLE_END, RC6_UNIT / 2))
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break;
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if (!(data->header & RC6_STARTBIT_MASK)) {
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IR_dprintk(1, "RC6 invalid start bit\n");
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break;
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}
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data->state = STATE_BODY_BIT_START;
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decrease_duration(&ev, RC6_TOGGLE_END);
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data->count = 0;
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data->body = 0;
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switch (rc6_mode(data)) {
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case RC6_MODE_0:
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data->wanted_bits = RC6_0_NBITS;
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break;
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case RC6_MODE_6A:
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data->wanted_bits = RC6_6A_NBITS;
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break;
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default:
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IR_dprintk(1, "RC6 unknown mode\n");
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goto out;
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}
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goto again;
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case STATE_BODY_BIT_START:
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if (eq_margin(ev.duration, RC6_BIT_START, RC6_UNIT / 2)) {
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/* Discard LSB's that won't fit in data->body */
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if (data->count++ < CHAR_BIT * sizeof data->body) {
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data->body <<= 1;
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if (ev.pulse)
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data->body |= 1;
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}
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data->state = STATE_BODY_BIT_END;
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return 0;
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} else if (RC6_MODE_6A == rc6_mode(data) && !ev.pulse &&
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geq_margin(ev.duration, RC6_SUFFIX_SPACE, RC6_UNIT / 2)) {
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data->state = STATE_FINISHED;
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goto again;
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}
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break;
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case STATE_BODY_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 == data->wanted_bits)
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data->state = STATE_FINISHED;
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else
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data->state = STATE_BODY_BIT_START;
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decrease_duration(&ev, RC6_BIT_END);
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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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switch (rc6_mode(data)) {
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case RC6_MODE_0:
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scancode = data->body;
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toggle = data->toggle;
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IR_dprintk(1, "RC6(0) scancode 0x%04x (toggle: %u)\n",
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scancode, toggle);
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break;
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case RC6_MODE_6A:
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if (data->count > CHAR_BIT * sizeof data->body) {
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IR_dprintk(1, "RC6 too many (%u) data bits\n",
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data->count);
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goto out;
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}
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scancode = data->body;
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if (data->count == RC6_6A_32_NBITS &&
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(scancode & RC6_6A_LCC_MASK) == RC6_6A_MCE_CC) {
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/* MCE RC */
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toggle = (scancode & RC6_6A_MCE_TOGGLE_MASK) ? 1 : 0;
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scancode &= ~RC6_6A_MCE_TOGGLE_MASK;
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} else {
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toggle = 0;
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}
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IR_dprintk(1, "RC6(6A) scancode 0x%08x (toggle: %u)\n",
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scancode, toggle);
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break;
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default:
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IR_dprintk(1, "RC6 unknown mode\n");
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goto out;
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}
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rc_keydown(dev, 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, "RC6 decode failed at state %i (%uus %s)\n",
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data->state, 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 rc6_handler = {
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.protocols = RC_TYPE_RC6,
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.decode = ir_rc6_decode,
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};
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static int __init ir_rc6_decode_init(void)
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{
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ir_raw_handler_register(&rc6_handler);
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printk(KERN_INFO "IR RC6 protocol handler initialized\n");
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return 0;
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}
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static void __exit ir_rc6_decode_exit(void)
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{
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ir_raw_handler_unregister(&rc6_handler);
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}
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module_init(ir_rc6_decode_init);
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module_exit(ir_rc6_decode_exit);
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MODULE_LICENSE("GPL");
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MODULE_AUTHOR("David Härdeman <david@hardeman.nu>");
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MODULE_DESCRIPTION("RC6 IR protocol decoder");
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