drivers/w1/w1_io.c

   1 /*
   2  *      w1_io.c
   3  *
   4  * Copyright (c) 2004 Evgeniy Polyakov <johnpol@2ka.mipt.ru>
   5  *
   6  *
   7  * This program is free software; you can redistribute it and/or modify
   8  * it under the terms of the GNU General Public License as published by
   9  * the Free Software Foundation; either version 2 of the License, or
  10  * (at your option) any later version.
  11  *
  12  * This program is distributed in the hope that it will be useful,
  13  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  14  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  15  * GNU General Public License for more details.
  16  *
  17  * You should have received a copy of the GNU General Public License
  18  * along with this program; if not, write to the Free Software
  19  * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
  20  */
  21
  22 #include <asm/io.h>
  23
  24 #include <linux/delay.h>
  25 #include <linux/moduleparam.h>
  26
  27 #include "w1.h"
  28 #include "w1_log.h"
  29 #include "w1_io.h"
  30
  31 int w1_delay_parm = 1;
  32 module_param_named(delay_coef, w1_delay_parm, int, 0);
  33
  34 static u8 w1_crc8_table[] = {
  35         0, 94, 188, 226, 97, 63, 221, 131, 194, 156, 126, 32, 163, 253, 31, 65,
  36         157, 195, 33, 127, 252, 162, 64, 30, 95, 1, 227, 189, 62, 96, 130, 220,
  37         35, 125, 159, 193, 66, 28, 254, 160, 225, 191, 93, 3, 128, 222, 60, 98,
  38         190, 224, 2, 92, 223, 129, 99, 61, 124, 34, 192, 158, 29, 67, 161, 255,
  39         70, 24, 250, 164, 39, 121, 155, 197, 132, 218, 56, 102, 229, 187, 89, 7,
  40         219, 133, 103, 57, 186, 228, 6, 88, 25, 71, 165, 251, 120, 38, 196, 154,
  41         101, 59, 217, 135, 4, 90, 184, 230, 167, 249, 27, 69, 198, 152, 122, 36,
  42         248, 166, 68, 26, 153, 199, 37, 123, 58, 100, 134, 216, 91, 5, 231, 185,
  43         140, 210, 48, 110, 237, 179, 81, 15, 78, 16, 242, 172, 47, 113, 147, 205,
  44         17, 79, 173, 243, 112, 46, 204, 146, 211, 141, 111, 49, 178, 236, 14, 80,
  45         175, 241, 19, 77, 206, 144, 114, 44, 109, 51, 209, 143, 12, 82, 176, 238,
  46         50, 108, 142, 208, 83, 13, 239, 177, 240, 174, 76, 18, 145, 207, 45, 115,
  47         202, 148, 118, 40, 171, 245, 23, 73, 8, 86, 180, 234, 105, 55, 213, 139,
  48         87, 9, 235, 181, 54, 104, 138, 212, 149, 203, 41, 119, 244, 170, 72, 22,
  49         233, 183, 85, 11, 136, 214, 52, 106, 43, 117, 151, 201, 74, 20, 246, 168,
  50         116, 42, 200, 150, 21, 75, 169, 247, 182, 232, 10, 84, 215, 137, 107, 53
  51 };
  52
  53 void w1_delay(unsigned long tm)
  54 {
  55         udelay(tm * w1_delay_parm);
  56 }
  57
  58 u8 w1_touch_bit(struct w1_master *dev, int bit)
  59 {
  60         if (dev->bus_master->touch_bit)
  61                 return dev->bus_master->touch_bit(dev->bus_master->data, bit);
  62         else
  63                 return w1_read_bit(dev);
  64 }
  65
  66 void w1_write_bit(struct w1_master *dev, int bit)
  67 {
  68         if (bit) {
  69                 dev->bus_master->write_bit(dev->bus_master->data, 0);
  70                 w1_delay(6);
  71                 dev->bus_master->write_bit(dev->bus_master->data, 1);
  72                 w1_delay(64);
  73         } else {
  74                 dev->bus_master->write_bit(dev->bus_master->data, 0);
  75                 w1_delay(60);
  76                 dev->bus_master->write_bit(dev->bus_master->data, 1);
  77                 w1_delay(10);
  78         }
  79 }
  80
  81 void w1_write_8(struct w1_master *dev, u8 byte)
  82 {
  83         int i;
  84
  85         if (dev->bus_master->write_byte)
  86                 dev->bus_master->write_byte(dev->bus_master->data, byte);
  87         else
  88                 for (i = 0; i < 8; ++i)
  89                         w1_write_bit(dev, (byte >> i) & 0x1);
  90 }
  91
  92 u8 w1_read_bit(struct w1_master *dev)
  93 {
  94         int result;
  95
  96         dev->bus_master->write_bit(dev->bus_master->data, 0);
  97         w1_delay(6);
  98         dev->bus_master->write_bit(dev->bus_master->data, 1);
  99         w1_delay(9);
 100
 101         result = dev->bus_master->read_bit(dev->bus_master->data);
 102         w1_delay(55);
 103
 104         return result & 0x1;
 105 }
 106
 107 u8 w1_read_8(struct w1_master * dev)
 108 {
 109         int i;
 110         u8 res = 0;
 111
 112         if (dev->bus_master->read_byte)
 113                 res = dev->bus_master->read_byte(dev->bus_master->data);
 114         else
 115                 for (i = 0; i < 8; ++i)
 116                         res |= (w1_read_bit(dev) << i);
 117
 118         return res;
 119 }
 120
 121 void w1_write_block(struct w1_master *dev, u8 *buf, int len)
 122 {
 123         int i;
 124
 125         if (dev->bus_master->write_block)
 126                 dev->bus_master->write_block(dev->bus_master->data, buf, len);
 127         else
 128                 for (i = 0; i < len; ++i)
 129                         w1_write_8(dev, buf[i]);
 130 }
 131
 132 u8 w1_read_block(struct w1_master *dev, u8 *buf, int len)
 133 {
 134         int i;
 135         u8 ret;
 136
 137         if (dev->bus_master->read_block)
 138                 ret = dev->bus_master->read_block(dev->bus_master->data, buf, len);
 139         else {
 140                 for (i = 0; i < len; ++i)
 141                         buf[i] = w1_read_8(dev);
 142                 ret = len;
 143         }
 144
 145         return ret;
 146 }
 147
 148 int w1_reset_bus(struct w1_master *dev)
 149 {
 150         int result = 0;
 151
 152         if (dev->bus_master->reset_bus)
 153                 result = dev->bus_master->reset_bus(dev->bus_master->data) & 0x1;
 154         else {
 155                 dev->bus_master->write_bit(dev->bus_master->data, 0);
 156                 w1_delay(480);
 157                 dev->bus_master->write_bit(dev->bus_master->data, 1);
 158                 w1_delay(70);
 159
 160                 result = dev->bus_master->read_bit(dev->bus_master->data) & 0x1;
 161                 w1_delay(410);
 162         }
 163
 164         return result;
 165 }
 166
 167 u8 w1_calc_crc8(u8 * data, int len)
 168 {
 169         u8 crc = 0;
 170
 171         while (len--)
 172                 crc = w1_crc8_table[crc ^ *data++];
 173
 174         return crc;
 175 }
 176
 177 void w1_search_devices(struct w1_master *dev, w1_slave_found_callback cb)
 178 {
 179         dev->attempts++;
 180         if (dev->bus_master->search)
 181                 dev->bus_master->search(dev->bus_master->data, cb);
 182         else
 183                 w1_search(dev);
 184 }
 185
 186 EXPORT_SYMBOL(w1_write_bit);
 187 EXPORT_SYMBOL(w1_write_8);
 188 EXPORT_SYMBOL(w1_read_bit);
 189 EXPORT_SYMBOL(w1_read_8);
 190 EXPORT_SYMBOL(w1_reset_bus);
 191 EXPORT_SYMBOL(w1_calc_crc8);
 192 EXPORT_SYMBOL(w1_delay);
 193 EXPORT_SYMBOL(w1_read_block);
 194 EXPORT_SYMBOL(w1_write_block);
 195 EXPORT_SYMBOL(w1_search_devices);