The Design and Implementation of the FreeBSD Operating System, Second Edition
Now available: The Design and Implementation of the FreeBSD Operating System (Second Edition)


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FreeBSD/Linux Kernel Cross Reference
sys/dev/ic/ds.h

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    1 /*      $NetBSD: ds.h,v 1.10 2012/02/12 16:34:11 matt 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(struct ds_handle *dsh)
  102 {
  103         u_int8_t buf;
  104         int i;
  105 
  106         for (i=buf=0; i<8; ++i)
  107                 buf |= (dsh->ds_read_bit)(dsh->ds_hw_handle) << i;
  108 
  109         return buf;
  110 }
  111 
  112 static __inline void
  113 ds_write_byte(struct ds_handle *dsh, unsigned int b)
  114 {
  115         int i;
  116 
  117         for (i=0; i<8; ++i) {
  118                 (dsh->ds_write_bit)(dsh->ds_hw_handle, b & 1);
  119                 b >>= 1;
  120         }
  121 }
  122 
  123 #endif /* DALLAS_SEMI_CHIPS_H */

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