1 /* $NetBSD: ds.h,v 1.9 2008/04/28 20:23:49 martin 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 */ 127