sys/dev/onewire/onewire_bitbang.c

   1 /* $NetBSD$ */
   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@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, "$NetBSD$");
  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 }