forked from Minki/linux
158 lines
3.9 KiB
C
158 lines
3.9 KiB
C
/* ir-raw-event.c - handle IR Pulse/Space event
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*
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* Copyright (C) 2010 by Mauro Carvalho Chehab <mchehab@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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#include <media/ir-core.h>
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/* Start time: 4.5 ms */
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#define MIN_START_TIME 3900000
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#define MAX_START_TIME 5100000
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/* Pulse time: 560 us */
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#define MIN_PULSE_TIME 460000
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#define MAX_PULSE_TIME 660000
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/* Bit 1 space time: 2.25ms-560 us */
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#define MIN_BIT1_TIME 1490000
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#define MAX_BIT1_TIME 1890000
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/* Bit 0 space time: 1.12ms-560 us */
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#define MIN_BIT0_TIME 360000
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#define MAX_BIT0_TIME 760000
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/**
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* __ir_nec_decode() - Decode one NEC pulsecode
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* @input_dev: the struct input_dev descriptor of the device
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* @evs: event array with type/duration of pulse/space
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* @len: length of the array
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* @pos: position to start seeking for a code
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* This function returns the decoded ircode or -EINVAL if no pulse got decoded
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*/
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static int __ir_nec_decode(struct input_dev *input_dev,
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struct ir_raw_event *evs,
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int len, int *pos)
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{
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int count = -1;
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int ircode = 0, not_code = 0;
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/* Be sure that the first event is an start one and is a pulse */
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for (; *pos < len; (*pos)++) {
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if (evs[*pos].type & (IR_START_EVENT | IR_PULSE))
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break;
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}
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(*pos)++; /* First event doesn't contain data */
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if (*pos >= len)
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return 0;
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/* First space should have 4.5 ms otherwise is not NEC protocol */
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if ((evs[*pos].delta.tv_nsec < MIN_START_TIME) |
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(evs[*pos].delta.tv_nsec > MAX_START_TIME) |
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(evs[*pos].type != IR_SPACE))
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goto err;
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/*
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* FIXME: need to implement the repeat sequence
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*/
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count = 0;
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for ((*pos)++; *pos < len; (*pos)++) {
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int bit;
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if ((evs[*pos].delta.tv_nsec < MIN_PULSE_TIME) |
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(evs[*pos].delta.tv_nsec > MAX_PULSE_TIME) |
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(evs[*pos].type != IR_PULSE))
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goto err;
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if (++*pos >= len)
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goto err;
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if (evs[*pos].type != IR_SPACE)
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goto err;
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if ((evs[*pos].delta.tv_nsec > MIN_BIT1_TIME) &&
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(evs[*pos].delta.tv_nsec < MAX_BIT1_TIME))
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bit = 1;
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else if ((evs[*pos].delta.tv_nsec > MIN_BIT0_TIME) &&
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(evs[*pos].delta.tv_nsec < MAX_BIT0_TIME))
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bit = 0;
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else
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goto err;
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if (bit) {
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int shift = count;
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/* Address first, then command */
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if (shift < 8) {
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shift += 8;
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ircode |= 1 << shift;
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} else if (shift < 16) {
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not_code |= 1 << shift;
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} else if (shift < 24) {
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shift -= 16;
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ircode |= 1 << shift;
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} else {
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shift -= 24;
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not_code |= 1 << shift;
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}
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}
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if (++count == 32)
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break;
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}
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/*
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* Fixme: may need to accept Extended NEC protocol?
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*/
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if ((ircode & ~not_code) != ircode) {
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IR_dprintk(1, "NEC checksum error: code 0x%04x, not-code 0x%04x\n",
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ircode, not_code);
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return -EINVAL;
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}
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IR_dprintk(1, "NEC scancode 0x%04x\n", ircode);
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ir_keydown(input_dev, ircode);
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ir_keyup(input_dev);
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return ircode;
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err:
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IR_dprintk(1, "NEC decoded failed at bit %d while decoding %luus time\n",
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count, (evs[*pos].delta.tv_nsec + 500) / 1000);
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return -EINVAL;
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}
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/**
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* __ir_nec_decode() - Decodes all NEC pulsecodes on a given array
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* @input_dev: the struct input_dev descriptor of the device
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* @evs: event array with type/duration of pulse/space
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* @len: length of the array
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* This function returns the number of decoded pulses or -EINVAL if no
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* pulse got decoded
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*/
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int ir_nec_decode(struct input_dev *input_dev,
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struct ir_raw_event *evs,
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int len)
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{
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int pos = 0;
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int rc = 0;
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while (pos < len) {
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if (__ir_nec_decode(input_dev, evs, len, &pos) >= 0)
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rc++;
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}
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if (!rc)
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return -EINVAL;
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return rc;
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}
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EXPORT_SYMBOL_GPL(ir_nec_decode);
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