Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1 | /* |
Evgeniy Polyakov | 7785925 | 2005-05-20 22:33:25 +0400 | [diff] [blame] | 2 | * w1_io.c |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 3 | * |
| 4 | * Copyright (c) 2004 Evgeniy Polyakov <johnpol@2ka.mipt.ru> |
Evgeniy Polyakov | 7785925 | 2005-05-20 22:33:25 +0400 | [diff] [blame] | 5 | * |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 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 | |
Adrian Bunk | a9fb1c7 | 2005-12-13 14:04:33 -0800 | [diff] [blame] | 31 | static int w1_delay_parm = 1; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 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 | |
Evgeniy Polyakov | be57ce2 | 2005-06-04 01:21:46 +0400 | [diff] [blame] | 58 | static void w1_write_bit(struct w1_master *dev, int bit); |
| 59 | static u8 w1_read_bit(struct w1_master *dev); |
| 60 | |
| 61 | /** |
| 62 | * Generates a write-0 or write-1 cycle and samples the level. |
| 63 | */ |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 64 | u8 w1_touch_bit(struct w1_master *dev, int bit) |
| 65 | { |
| 66 | if (dev->bus_master->touch_bit) |
| 67 | return dev->bus_master->touch_bit(dev->bus_master->data, bit); |
Evgeniy Polyakov | be57ce2 | 2005-06-04 01:21:46 +0400 | [diff] [blame] | 68 | else if (bit) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 69 | return w1_read_bit(dev); |
Evgeniy Polyakov | be57ce2 | 2005-06-04 01:21:46 +0400 | [diff] [blame] | 70 | else { |
| 71 | w1_write_bit(dev, 0); |
| 72 | return(0); |
| 73 | } |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 74 | } |
| 75 | |
Evgeniy Polyakov | be57ce2 | 2005-06-04 01:21:46 +0400 | [diff] [blame] | 76 | /** |
| 77 | * Generates a write-0 or write-1 cycle. |
| 78 | * Only call if dev->bus_master->touch_bit is NULL |
| 79 | */ |
| 80 | static void w1_write_bit(struct w1_master *dev, int bit) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 81 | { |
| 82 | if (bit) { |
| 83 | dev->bus_master->write_bit(dev->bus_master->data, 0); |
| 84 | w1_delay(6); |
| 85 | dev->bus_master->write_bit(dev->bus_master->data, 1); |
| 86 | w1_delay(64); |
| 87 | } else { |
| 88 | dev->bus_master->write_bit(dev->bus_master->data, 0); |
| 89 | w1_delay(60); |
| 90 | dev->bus_master->write_bit(dev->bus_master->data, 1); |
| 91 | w1_delay(10); |
| 92 | } |
| 93 | } |
| 94 | |
Evgeniy Polyakov | be57ce2 | 2005-06-04 01:21:46 +0400 | [diff] [blame] | 95 | /** |
| 96 | * Writes 8 bits. |
| 97 | * |
| 98 | * @param dev the master device |
| 99 | * @param byte the byte to write |
| 100 | */ |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 101 | void w1_write_8(struct w1_master *dev, u8 byte) |
| 102 | { |
| 103 | int i; |
| 104 | |
| 105 | if (dev->bus_master->write_byte) |
| 106 | dev->bus_master->write_byte(dev->bus_master->data, byte); |
| 107 | else |
| 108 | for (i = 0; i < 8; ++i) |
Evgeniy Polyakov | be57ce2 | 2005-06-04 01:21:46 +0400 | [diff] [blame] | 109 | w1_touch_bit(dev, (byte >> i) & 0x1); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 110 | } |
| 111 | |
Evgeniy Polyakov | be57ce2 | 2005-06-04 01:21:46 +0400 | [diff] [blame] | 112 | |
| 113 | /** |
| 114 | * Generates a write-1 cycle and samples the level. |
| 115 | * Only call if dev->bus_master->touch_bit is NULL |
| 116 | */ |
| 117 | static u8 w1_read_bit(struct w1_master *dev) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 118 | { |
| 119 | int result; |
| 120 | |
| 121 | dev->bus_master->write_bit(dev->bus_master->data, 0); |
| 122 | w1_delay(6); |
| 123 | dev->bus_master->write_bit(dev->bus_master->data, 1); |
| 124 | w1_delay(9); |
| 125 | |
| 126 | result = dev->bus_master->read_bit(dev->bus_master->data); |
| 127 | w1_delay(55); |
| 128 | |
| 129 | return result & 0x1; |
| 130 | } |
| 131 | |
Evgeniy Polyakov | be57ce2 | 2005-06-04 01:21:46 +0400 | [diff] [blame] | 132 | /** |
Evgeniy Polyakov | 6b72986 | 2005-06-04 01:30:43 +0400 | [diff] [blame] | 133 | * Does a triplet - used for searching ROM addresses. |
| 134 | * Return bits: |
| 135 | * bit 0 = id_bit |
| 136 | * bit 1 = comp_bit |
| 137 | * bit 2 = dir_taken |
| 138 | * If both bits 0 & 1 are set, the search should be restarted. |
| 139 | * |
| 140 | * @param dev the master device |
| 141 | * @param bdir the bit to write if both id_bit and comp_bit are 0 |
| 142 | * @return bit fields - see above |
| 143 | */ |
| 144 | u8 w1_triplet(struct w1_master *dev, int bdir) |
| 145 | { |
| 146 | if ( dev->bus_master->triplet ) |
| 147 | return(dev->bus_master->triplet(dev->bus_master->data, bdir)); |
| 148 | else { |
| 149 | u8 id_bit = w1_touch_bit(dev, 1); |
| 150 | u8 comp_bit = w1_touch_bit(dev, 1); |
| 151 | u8 retval; |
| 152 | |
| 153 | if ( id_bit && comp_bit ) |
| 154 | return(0x03); /* error */ |
| 155 | |
| 156 | if ( !id_bit && !comp_bit ) { |
| 157 | /* Both bits are valid, take the direction given */ |
| 158 | retval = bdir ? 0x04 : 0; |
| 159 | } else { |
| 160 | /* Only one bit is valid, take that direction */ |
| 161 | bdir = id_bit; |
| 162 | retval = id_bit ? 0x05 : 0x02; |
| 163 | } |
| 164 | |
| 165 | if ( dev->bus_master->touch_bit ) |
| 166 | w1_touch_bit(dev, bdir); |
| 167 | else |
| 168 | w1_write_bit(dev, bdir); |
| 169 | return(retval); |
| 170 | } |
| 171 | } |
| 172 | |
| 173 | /** |
Evgeniy Polyakov | be57ce2 | 2005-06-04 01:21:46 +0400 | [diff] [blame] | 174 | * Reads 8 bits. |
| 175 | * |
| 176 | * @param dev the master device |
| 177 | * @return the byte read |
| 178 | */ |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 179 | u8 w1_read_8(struct w1_master * dev) |
| 180 | { |
| 181 | int i; |
| 182 | u8 res = 0; |
| 183 | |
| 184 | if (dev->bus_master->read_byte) |
| 185 | res = dev->bus_master->read_byte(dev->bus_master->data); |
| 186 | else |
| 187 | for (i = 0; i < 8; ++i) |
Evgeniy Polyakov | be57ce2 | 2005-06-04 01:21:46 +0400 | [diff] [blame] | 188 | res |= (w1_touch_bit(dev,1) << i); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 189 | |
| 190 | return res; |
| 191 | } |
| 192 | |
Evgeniy Polyakov | be57ce2 | 2005-06-04 01:21:46 +0400 | [diff] [blame] | 193 | /** |
| 194 | * Writes a series of bytes. |
| 195 | * |
| 196 | * @param dev the master device |
| 197 | * @param buf pointer to the data to write |
| 198 | * @param len the number of bytes to write |
| 199 | * @return the byte read |
| 200 | */ |
| 201 | void w1_write_block(struct w1_master *dev, const u8 *buf, int len) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 202 | { |
| 203 | int i; |
| 204 | |
| 205 | if (dev->bus_master->write_block) |
| 206 | dev->bus_master->write_block(dev->bus_master->data, buf, len); |
| 207 | else |
| 208 | for (i = 0; i < len; ++i) |
| 209 | w1_write_8(dev, buf[i]); |
| 210 | } |
| 211 | |
Evgeniy Polyakov | be57ce2 | 2005-06-04 01:21:46 +0400 | [diff] [blame] | 212 | /** |
| 213 | * Reads a series of bytes. |
| 214 | * |
| 215 | * @param dev the master device |
| 216 | * @param buf pointer to the buffer to fill |
| 217 | * @param len the number of bytes to read |
| 218 | * @return the number of bytes read |
| 219 | */ |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 220 | u8 w1_read_block(struct w1_master *dev, u8 *buf, int len) |
| 221 | { |
| 222 | int i; |
| 223 | u8 ret; |
| 224 | |
| 225 | if (dev->bus_master->read_block) |
| 226 | ret = dev->bus_master->read_block(dev->bus_master->data, buf, len); |
| 227 | else { |
| 228 | for (i = 0; i < len; ++i) |
| 229 | buf[i] = w1_read_8(dev); |
| 230 | ret = len; |
| 231 | } |
| 232 | |
| 233 | return ret; |
| 234 | } |
| 235 | |
Evgeniy Polyakov | be57ce2 | 2005-06-04 01:21:46 +0400 | [diff] [blame] | 236 | /** |
| 237 | * Issues a reset bus sequence. |
| 238 | * |
| 239 | * @param dev The bus master pointer |
| 240 | * @return 0=Device present, 1=No device present or error |
| 241 | */ |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 242 | int w1_reset_bus(struct w1_master *dev) |
| 243 | { |
Evgeniy Polyakov | be57ce2 | 2005-06-04 01:21:46 +0400 | [diff] [blame] | 244 | int result; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 245 | |
| 246 | if (dev->bus_master->reset_bus) |
| 247 | result = dev->bus_master->reset_bus(dev->bus_master->data) & 0x1; |
| 248 | else { |
| 249 | dev->bus_master->write_bit(dev->bus_master->data, 0); |
| 250 | w1_delay(480); |
| 251 | dev->bus_master->write_bit(dev->bus_master->data, 1); |
| 252 | w1_delay(70); |
| 253 | |
| 254 | result = dev->bus_master->read_bit(dev->bus_master->data) & 0x1; |
| 255 | w1_delay(410); |
| 256 | } |
| 257 | |
| 258 | return result; |
| 259 | } |
| 260 | |
| 261 | u8 w1_calc_crc8(u8 * data, int len) |
| 262 | { |
| 263 | u8 crc = 0; |
| 264 | |
| 265 | while (len--) |
| 266 | crc = w1_crc8_table[crc ^ *data++]; |
| 267 | |
| 268 | return crc; |
| 269 | } |
| 270 | |
| 271 | void w1_search_devices(struct w1_master *dev, w1_slave_found_callback cb) |
| 272 | { |
| 273 | dev->attempts++; |
| 274 | if (dev->bus_master->search) |
| 275 | dev->bus_master->search(dev->bus_master->data, cb); |
| 276 | else |
Evgeniy Polyakov | 6b72986 | 2005-06-04 01:30:43 +0400 | [diff] [blame] | 277 | w1_search(dev, cb); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 278 | } |
| 279 | |
Evgeniy Polyakov | ea7d8f6 | 2005-08-11 17:27:49 +0400 | [diff] [blame] | 280 | /** |
| 281 | * Resets the bus and then selects the slave by sending either a skip rom |
| 282 | * or a rom match. |
| 283 | * The w1 master lock must be held. |
| 284 | * |
| 285 | * @param sl the slave to select |
| 286 | * @return 0=success, anything else=error |
| 287 | */ |
| 288 | int w1_reset_select_slave(struct w1_slave *sl) |
| 289 | { |
| 290 | if (w1_reset_bus(sl->master)) |
| 291 | return -1; |
| 292 | |
| 293 | if (sl->master->slave_count == 1) |
| 294 | w1_write_8(sl->master, W1_SKIP_ROM); |
| 295 | else { |
| 296 | u8 match[9] = {W1_MATCH_ROM, }; |
| 297 | memcpy(&match[1], (u8 *)&sl->reg_num, 8); |
| 298 | w1_write_block(sl->master, match, 9); |
| 299 | } |
| 300 | return 0; |
| 301 | } |
| 302 | |
Evgeniy Polyakov | be57ce2 | 2005-06-04 01:21:46 +0400 | [diff] [blame] | 303 | EXPORT_SYMBOL(w1_touch_bit); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 304 | EXPORT_SYMBOL(w1_write_8); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 305 | EXPORT_SYMBOL(w1_read_8); |
| 306 | EXPORT_SYMBOL(w1_reset_bus); |
| 307 | EXPORT_SYMBOL(w1_calc_crc8); |
| 308 | EXPORT_SYMBOL(w1_delay); |
| 309 | EXPORT_SYMBOL(w1_read_block); |
| 310 | EXPORT_SYMBOL(w1_write_block); |
| 311 | EXPORT_SYMBOL(w1_search_devices); |
Evgeniy Polyakov | ea7d8f6 | 2005-08-11 17:27:49 +0400 | [diff] [blame] | 312 | EXPORT_SYMBOL(w1_reset_select_slave); |