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226 lines
6.0 KiB
C
226 lines
6.0 KiB
C
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/* ir-xmp-decoder.c - handle XMP IR Pulse/Space protocol
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*
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* Copyright (C) 2014 by Marcel Mol
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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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* - Based on info from http://www.hifi-remote.com
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* - Ignore Toggle=9 frames
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* - Ignore XMP-1 XMP-2 difference, always store 16 bit OBC
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*/
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#include <linux/bitrev.h>
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#include <linux/module.h>
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#include "rc-core-priv.h"
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#define XMP_UNIT 136000 /* ns */
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#define XMP_LEADER 210000 /* ns */
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#define XMP_NIBBLE_PREFIX 760000 /* ns */
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#define XMP_HALFFRAME_SPACE 13800000 /* ns */
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#define XMP_TRAILER_SPACE 20000000 /* should be 80ms but not all dureation supliers can go that high */
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enum xmp_state {
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STATE_INACTIVE,
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STATE_LEADER_PULSE,
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STATE_NIBBLE_SPACE,
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};
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/**
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* ir_xmp_decode() - Decode one XMP pulse or space
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* @dev: the struct rc_dev descriptor of the device
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* @duration: 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_xmp_decode(struct rc_dev *dev, struct ir_raw_event ev)
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{
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struct xmp_dec *data = &dev->raw->xmp;
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if (!(dev->enabled_protocols & RC_BIT_XMP))
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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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IR_dprintk(2, "XMP decode started at state %d %d (%uus %s)\n",
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data->state, data->count, TO_US(ev.duration), TO_STR(ev.pulse));
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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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if (eq_margin(ev.duration, XMP_LEADER, XMP_UNIT / 2)) {
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data->count = 0;
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data->state = STATE_NIBBLE_SPACE;
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}
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return 0;
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case STATE_LEADER_PULSE:
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if (!ev.pulse)
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break;
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if (eq_margin(ev.duration, XMP_LEADER, XMP_UNIT / 2))
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data->state = STATE_NIBBLE_SPACE;
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return 0;
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case STATE_NIBBLE_SPACE:
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if (ev.pulse)
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break;
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if (geq_margin(ev.duration, XMP_TRAILER_SPACE, XMP_NIBBLE_PREFIX)) {
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int divider, i;
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u8 addr, subaddr, subaddr2, toggle, oem, obc1, obc2, sum1, sum2;
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u32 *n;
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u32 scancode;
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if (data->count != 16) {
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IR_dprintk(2, "received TRAILER period at index %d: %u\n",
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data->count, ev.duration);
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data->state = STATE_INACTIVE;
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return -EINVAL;
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}
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n = data->durations;
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/*
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* the 4th nibble should be 15 so base the divider on this
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* to transform durations into nibbles. Substract 2000 from
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* the divider to compensate for fluctuations in the signal
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*/
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divider = (n[3] - XMP_NIBBLE_PREFIX) / 15 - 2000;
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if (divider < 50) {
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IR_dprintk(2, "divider to small %d.\n", divider);
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data->state = STATE_INACTIVE;
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return -EINVAL;
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}
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/* convert to nibbles and do some sanity checks */
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for (i = 0; i < 16; i++)
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n[i] = (n[i] - XMP_NIBBLE_PREFIX) / divider;
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sum1 = (15 + n[0] + n[1] + n[2] + n[3] +
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n[4] + n[5] + n[6] + n[7]) % 16;
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sum2 = (15 + n[8] + n[9] + n[10] + n[11] +
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n[12] + n[13] + n[14] + n[15]) % 16;
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if (sum1 != 15 || sum2 != 15) {
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IR_dprintk(2, "checksum errors sum1=0x%X sum2=0x%X\n",
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sum1, sum2);
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data->state = STATE_INACTIVE;
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return -EINVAL;
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}
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subaddr = n[0] << 4 | n[2];
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subaddr2 = n[8] << 4 | n[11];
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oem = n[4] << 4 | n[5];
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addr = n[6] << 4 | n[7];
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toggle = n[10];
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obc1 = n[12] << 4 | n[13];
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obc2 = n[14] << 4 | n[15];
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if (subaddr != subaddr2) {
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IR_dprintk(2, "subaddress nibbles mismatch 0x%02X != 0x%02X\n",
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subaddr, subaddr2);
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data->state = STATE_INACTIVE;
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return -EINVAL;
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}
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if (oem != 0x44)
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IR_dprintk(1, "Warning: OEM nibbles 0x%02X. Expected 0x44\n",
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oem);
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scancode = addr << 24 | subaddr << 16 |
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obc1 << 8 | obc2;
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IR_dprintk(1, "XMP scancode 0x%06x\n", scancode);
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if (toggle == 0) {
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rc_keydown(dev, RC_TYPE_XMP, scancode, 0);
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} else {
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rc_repeat(dev);
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IR_dprintk(1, "Repeat last key\n");
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}
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data->state = STATE_INACTIVE;
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return 0;
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} else if (geq_margin(ev.duration, XMP_HALFFRAME_SPACE, XMP_NIBBLE_PREFIX)) {
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/* Expect 8 or 16 nibble pulses. 16 in case of 'final' frame */
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if (data->count == 16) {
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IR_dprintk(2, "received half frame pulse at index %d. Probably a final frame key-up event: %u\n",
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data->count, ev.duration);
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/*
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* TODO: for now go back to half frame position
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* so trailer can be found and key press
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* can be handled.
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*/
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data->count = 8;
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}
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else if (data->count != 8)
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IR_dprintk(2, "received half frame pulse at index %d: %u\n",
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data->count, ev.duration);
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data->state = STATE_LEADER_PULSE;
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return 0;
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} else if (geq_margin(ev.duration, XMP_NIBBLE_PREFIX, XMP_UNIT)) {
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/* store nibble raw data, decode after trailer */
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if (data->count == 16) {
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IR_dprintk(2, "to many pulses (%d) ignoring: %u\n",
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data->count, ev.duration);
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data->state = STATE_INACTIVE;
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return -EINVAL;
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}
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data->durations[data->count] = ev.duration;
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data->count++;
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data->state = STATE_LEADER_PULSE;
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return 0;
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}
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break;
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}
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IR_dprintk(1, "XMP decode failed at count %d state %d (%uus %s)\n",
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data->count, 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 xmp_handler = {
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.protocols = RC_BIT_XMP,
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.decode = ir_xmp_decode,
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};
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static int __init ir_xmp_decode_init(void)
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{
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ir_raw_handler_register(&xmp_handler);
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printk(KERN_INFO "IR XMP protocol handler initialized\n");
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return 0;
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}
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static void __exit ir_xmp_decode_exit(void)
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{
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ir_raw_handler_unregister(&xmp_handler);
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}
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module_init(ir_xmp_decode_init);
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module_exit(ir_xmp_decode_exit);
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MODULE_LICENSE("GPL");
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MODULE_AUTHOR("Marcel Mol <marcel@mesa.nl>");
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MODULE_AUTHOR("MESA Consulting (http://www.mesa.nl)");
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MODULE_DESCRIPTION("XMP IR protocol decoder");
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