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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 */
    124