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); 196