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onewire_bitbang.c revision 1.1 
      1 /* $NetBSD: onewire_bitbang.c,v 1.1 2006/04/07 18:55:22 riz Exp $ */
      2 /*	$OpenBSD: onewire_bitbang.c,v 1.1 2006/03/04 16:27:03 grange Exp $	*/
      3 
      4 /*
      5  * Copyright (c) 2006 Alexander Yurchenko <grange (at) openbsd.org>
      6  *
      7  * Permission to use, copy, modify, and distribute this software for any
      8  * purpose with or without fee is hereby granted, provided that the above
      9  * copyright notice and this permission notice appear in all copies.
     10  *
     11  * THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES
     12  * WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF
     13  * MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR
     14  * ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
     15  * WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN
     16  * ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF
     17  * OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
     18  */
     19 
     20 #include <sys/cdefs.h>
     21 __KERNEL_RCSID(0, "$NetBSD: onewire_bitbang.c,v 1.1 2006/04/07 18:55:22 riz Exp $");
     22 
     23 /*
     24  * 1-Wire bus bit-banging routines.
     25  */
     26 
     27 #include <sys/param.h>
     28 #include <sys/systm.h>
     29 #include <sys/device.h>
     30 
     31 #include <dev/onewire/onewirevar.h>
     32 
     33 int
     34 onewire_bb_reset(const struct onewire_bbops *ops, void *arg)
     35 {
     36 	int s, rv = 0, i;
     37 
     38 	s = splhigh();
     39 	ops->bb_tx(arg);
     40 	ops->bb_set(arg, 0);
     41 	DELAY(480);
     42 	ops->bb_set(arg, 1);
     43 	ops->bb_rx(arg);
     44 	DELAY(30);
     45 	for (i = 0; i < 6; i++) {
     46 		if ((rv = ops->bb_get(arg)) == 0)
     47 			break;
     48 		DELAY(20);
     49 	}
     50 	DELAY(450);
     51 	splx(s);
     52 
     53 	return (rv);
     54 }
     55 
     56 int
     57 onewire_bb_bit(const struct onewire_bbops *ops, void *arg, int value)
     58 {
     59 	int s, rv = 0, i;
     60 
     61 	s = splhigh();
     62 	ops->bb_tx(arg);
     63 	ops->bb_set(arg, 0);
     64 	DELAY(2);
     65 	if (value) {
     66 		ops->bb_set(arg, 1);
     67 		ops->bb_rx(arg);
     68 		for (i = 0; i < 15; i++) {
     69 			if ((rv = ops->bb_get(arg)) == 0)
     70 				break;
     71 			DELAY(2);
     72 		}
     73 		ops->bb_tx(arg);
     74 	}
     75 	DELAY(60);
     76 	ops->bb_set(arg, 1);
     77 	DELAY(5);
     78 	splx(s);
     79 
     80 	return (rv);
     81 }
     82