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/* $OpenBSD: onewire_bitbang.c,v 1.2 2010/07/02 03:13:42 tedu Exp $ */
/*
* Copyright (c) 2006 Alexander Yurchenko <grange@openbsd.org>
*
* Permission to use, copy, modify, and distribute this software for any
* purpose with or without fee is hereby granted, provided that the above
* copyright notice and this permission notice appear in all copies.
*
* THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES
* WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF
* MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR
* ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
* WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN
* ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF
* OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
*/
/*
* 1-Wire bus bit-banging routines.
*/
#include <sys/param.h>
#include <sys/systm.h>
#include <sys/device.h>
#include <dev/onewire/onewirevar.h>
int
onewire_bb_reset(const struct onewire_bbops *ops, void *arg)
{
int s, rv, i;
s = splhigh();
ops->bb_tx(arg);
ops->bb_set(arg, 0);
DELAY(480);
ops->bb_set(arg, 1);
ops->bb_rx(arg);
DELAY(30);
for (i = 0; i < 6; i++) {
if ((rv = ops->bb_get(arg)) == 0)
break;
DELAY(20);
}
DELAY(450);
splx(s);
return (rv);
}
int
onewire_bb_bit(const struct onewire_bbops *ops, void *arg, int value)
{
int s, rv, i;
s = splhigh();
ops->bb_tx(arg);
ops->bb_set(arg, 0);
DELAY(2);
rv = 0;
if (value) {
ops->bb_set(arg, 1);
ops->bb_rx(arg);
for (i = 0; i < 15; i++) {
if ((rv = ops->bb_get(arg)) == 0)
break;
DELAY(2);
}
ops->bb_tx(arg);
}
DELAY(60);
ops->bb_set(arg, 1);
DELAY(5);
splx(s);
return (rv);
}
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