sys/dev/ic/ds.h

   1 /*      $NetBSD: ds.h,v 1.8 2006/02/16 20:17:16 perry Exp $     */
   2
   3 /*-
   4  * Copyright (c) 1997 The NetBSD Foundation, Inc.
   5  * All rights reserved.
   6  *
   7  * This code is derived from software contributed to The NetBSD Foundation
   8  * by Ignatios Souvatzis.
   9  *
  10  * Redistribution and use in source and binary forms, with or without
  11  * modification, are permitted provided that the following conditions
  12  * are met:
  13  * 1. Redistributions of source code must retain the above copyright
  14  *    notice, this list of conditions and the following disclaimer.
  15  * 2. Redistributions in binary form must reproduce the above copyright
  16  *    notice, this list of conditions and the following disclaimer in the
  17  *    documentation and/or other materials provided with the distribution.
  18  *
  19  * THIS SOFTWARE IS PROVIDED BY THE NETBSD FOUNDATION, INC. AND CONTRIBUTORS
  20  * ``AS IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED
  21  * TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
  22  * PURPOSE ARE DISCLAIMED.  IN NO EVENT SHALL THE FOUNDATION OR CONTRIBUTORS
  23  * BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
  24  * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
  25  * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
  26  * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
  27  * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
  28  * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
  29  * POSSIBILITY OF SUCH DAMAGE.
  30  */
  31
  32 /*
  33  * Definitions for access to Dallas Semiconductor chips which attach to
  34  * the same 1-wire bus as the DS2404 RTC.
  35  */
  36
  37 #ifndef DALLAS_SEMI_CHIPS_H
  38 #define DALLAS_SEMI_CHIPS_H
  39
  40 /* Family codes (low byte of the ROM) */
  41
  42 #define DS_FAMILY_2401  0x01    /* DS2401 Silicon Serial Number */
  43 #define DS_FAMILY_2404  0x04    /* DS2404 Econoram Time Chip */
  44
  45 /*
  46  * ROM access codes. These are only available from the 1-wire bus, and one
  47  * of them MUST be used before a memory access code is called. If you want
  48  * to detect which devices are on the bus, you have to issue the ROM search
  49  * function (see data sheet).
  50  * If only one device is on the BUS, and you don't want any ROM function,
  51  * issue the SKIP function.
  52  * READ ROM works only if only one device is on the bus.
  53  */
  54
  55 #define DS_ROM_MATCH            0x55    /* 55 8-bytes-of-ROM-to-select */
  56 #define DS_ROM_SEARCH           0xf0    /* see data sheet */
  57 #define DS_ROM_SKIP             0xCC    /* don't do ROM function */
  58 #define DS_ROM_READ             0x33    /* 33 -> 8 bytes of ROM */
  59
  60 /*
  61  * Memory access codes. These are available from the 1- or 3-wire bus, and
  62  * but you must use one of the ROM access codes first, if using the 1-wire
  63  * bus.
  64  *
  65  * You can read from any starting address up to the end of the chip, or
  66  * abort the read with a reset pulse.
  67  * You first write 2-32 bytes beginning some address to the scratchpad.
  68  * Starting address and final byte stream length are remembered by the
  69  * chip. After reading data and address/length back from the scratchpad,
  70  * and verifying the information, you can issue the copy scratchpad command
  71  * to copy the written parts of the scratchpad to the corresponding parts
  72  * of the implied (in the address) memory page.
  73  */
  74
  75 #define DS_MEM_WRITE_SCRATCH    0x0f    /* 0F low-ads high-ads data ... */
  76 #define DS_MEM_READ_SCRATCH     0xaa    /* AA -> low-ads high-ads end-ofs
  77                                          * data ... */
  78 #define DS_MEM_COPY_SCRATCH     0x55    /* 55 low-ads high-ads end-ofs */
  79 #define DS_MEM_READ_MEMORY      0xf0    /* F0 low-ads high-ads -> data ...*/
  80
  81 /*
  82  * Hardware handle for access functions
  83  */
  84
  85 struct ds_handle {
  86         int (*ds_read_bit)(void *);
  87         void (*ds_write_bit)(void *, int);
  88         void (*ds_reset)(void *);
  89         void *ds_hw_handle;
  90 };
  91
  92 /*
  93  * Functions for access to Dallas Semiconductor chips which attach to
  94  * the same 1-wire bus as the DS2404 RTC.
  95  */
  96
  97 static u_int8_t ds_read_byte(struct ds_handle *);
  98 static void ds_write_byte(struct ds_handle *, unsigned int);
  99
 100 static __inline u_int8_t
 101 ds_read_byte(dsh)
 102         struct ds_handle *dsh;
 103 {
 104         u_int8_t buf;
 105         int i;
 106
 107         for (i=buf=0; i<8; ++i)
 108                 buf |= (dsh->ds_read_bit)(dsh->ds_hw_handle) << i;
 109
 110         return buf;
 111 }
 112
 113 static __inline void
 114 ds_write_byte(dsh, b)
 115         struct ds_handle *dsh;
 116         unsigned int b;
 117 {
 118         int i;
 119
 120         for (i=0; i<8; ++i) {
 121                 (dsh->ds_write_bit)(dsh->ds_hw_handle, b & 1);
 122                 b >>= 1;
 123         }
 124 }
 125
 126 #endif /* DALLAS_SEMI_CHIPS_H */