1 /* 2 * w1_therm.c 3 * 4 * Copyright (c) 2004 Evgeniy Polyakov <zbr@ioremap.net> 5 * 6 * 7 * This program is free software; you can redistribute it and/or modify 8 * it under the therms 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/types.h> 23 24 #include <linux/kernel.h> 25 #include <linux/module.h> 26 #include <linux/moduleparam.h> 27 #include <linux/sched.h> 28 #include <linux/device.h> 29 #include <linux/types.h> 30 #include <linux/slab.h> 31 #include <linux/delay.h> 32 33 #include "../w1.h" 34 #include "../w1_int.h" 35 #include "../w1_family.h" 36 37 MODULE_LICENSE("GPL"); 38 MODULE_AUTHOR("Evgeniy Polyakov <zbr@ioremap.net>"); 39 MODULE_DESCRIPTION("Driver for 1-wire Dallas network protocol, temperature family."); 40 MODULE_ALIAS("w1-family-" __stringify(W1_THERM_DS18S20)); 41 MODULE_ALIAS("w1-family-" __stringify(W1_THERM_DS1822)); 42 MODULE_ALIAS("w1-family-" __stringify(W1_THERM_DS18B20)); 43 MODULE_ALIAS("w1-family-" __stringify(W1_THERM_DS1825)); 44 MODULE_ALIAS("w1-family-" __stringify(W1_THERM_DS28EA00)); 45 46 /* Allow the strong pullup to be disabled, but default to enabled. 47 * If it was disabled a parasite powered device might not get the require 48 * current to do a temperature conversion. If it is enabled parasite powered 49 * devices have a better chance of getting the current required. 50 * In case the parasite power-detection is not working (seems to be the case 51 * for some DS18S20) the strong pullup can also be forced, regardless of the 52 * power state of the devices. 53 * 54 * Summary of options: 55 * - strong_pullup = 0 Disable strong pullup completely 56 * - strong_pullup = 1 Enable automatic strong pullup detection 57 * - strong_pullup = 2 Force strong pullup 58 */ 59 static int w1_strong_pullup = 1; 60 module_param_named(strong_pullup, w1_strong_pullup, int, 0); 61 62 struct w1_therm_family_data { 63 uint8_t rom[9]; 64 atomic_t refcnt; 65 }; 66 67 /* return the address of the refcnt in the family data */ 68 #define THERM_REFCNT(family_data) \ 69 (&((struct w1_therm_family_data *)family_data)->refcnt) 70 71 static int w1_therm_add_slave(struct w1_slave *sl) 72 { 73 sl->family_data = kzalloc(sizeof(struct w1_therm_family_data), 74 GFP_KERNEL); 75 if (!sl->family_data) 76 return -ENOMEM; 77 atomic_set(THERM_REFCNT(sl->family_data), 1); 78 return 0; 79 } 80 81 static void w1_therm_remove_slave(struct w1_slave *sl) 82 { 83 int refcnt = atomic_sub_return(1, THERM_REFCNT(sl->family_data)); 84 85 while (refcnt) { 86 msleep(1000); 87 refcnt = atomic_read(THERM_REFCNT(sl->family_data)); 88 } 89 kfree(sl->family_data); 90 sl->family_data = NULL; 91 } 92 93 static ssize_t w1_slave_show(struct device *device, 94 struct device_attribute *attr, char *buf); 95 96 static ssize_t w1_slave_store(struct device *device, 97 struct device_attribute *attr, const char *buf, size_t size); 98 99 static ssize_t w1_seq_show(struct device *device, 100 struct device_attribute *attr, char *buf); 101 102 static DEVICE_ATTR_RW(w1_slave); 103 static DEVICE_ATTR_RO(w1_seq); 104 105 static struct attribute *w1_therm_attrs[] = { 106 &dev_attr_w1_slave.attr, 107 NULL, 108 }; 109 110 static struct attribute *w1_ds28ea00_attrs[] = { 111 &dev_attr_w1_slave.attr, 112 &dev_attr_w1_seq.attr, 113 NULL, 114 }; 115 ATTRIBUTE_GROUPS(w1_therm); 116 ATTRIBUTE_GROUPS(w1_ds28ea00); 117 118 static struct w1_family_ops w1_therm_fops = { 119 .add_slave = w1_therm_add_slave, 120 .remove_slave = w1_therm_remove_slave, 121 .groups = w1_therm_groups, 122 }; 123 124 static struct w1_family_ops w1_ds28ea00_fops = { 125 .add_slave = w1_therm_add_slave, 126 .remove_slave = w1_therm_remove_slave, 127 .groups = w1_ds28ea00_groups, 128 }; 129 130 static struct w1_family w1_therm_family_DS18S20 = { 131 .fid = W1_THERM_DS18S20, 132 .fops = &w1_therm_fops, 133 }; 134 135 static struct w1_family w1_therm_family_DS18B20 = { 136 .fid = W1_THERM_DS18B20, 137 .fops = &w1_therm_fops, 138 }; 139 140 static struct w1_family w1_therm_family_DS1822 = { 141 .fid = W1_THERM_DS1822, 142 .fops = &w1_therm_fops, 143 }; 144 145 static struct w1_family w1_therm_family_DS28EA00 = { 146 .fid = W1_THERM_DS28EA00, 147 .fops = &w1_ds28ea00_fops, 148 }; 149 150 static struct w1_family w1_therm_family_DS1825 = { 151 .fid = W1_THERM_DS1825, 152 .fops = &w1_therm_fops, 153 }; 154 155 struct w1_therm_family_converter { 156 u8 broken; 157 u16 reserved; 158 struct w1_family *f; 159 int (*convert)(u8 rom[9]); 160 int (*precision)(struct device *device, int val); 161 int (*eeprom)(struct device *device); 162 }; 163 164 /* write configuration to eeprom */ 165 static inline int w1_therm_eeprom(struct device *device); 166 167 /* Set precision for conversion */ 168 static inline int w1_DS18B20_precision(struct device *device, int val); 169 static inline int w1_DS18S20_precision(struct device *device, int val); 170 171 /* The return value is millidegrees Centigrade. */ 172 static inline int w1_DS18B20_convert_temp(u8 rom[9]); 173 static inline int w1_DS18S20_convert_temp(u8 rom[9]); 174 175 static struct w1_therm_family_converter w1_therm_families[] = { 176 { 177 .f = &w1_therm_family_DS18S20, 178 .convert = w1_DS18S20_convert_temp, 179 .precision = w1_DS18S20_precision, 180 .eeprom = w1_therm_eeprom 181 }, 182 { 183 .f = &w1_therm_family_DS1822, 184 .convert = w1_DS18B20_convert_temp, 185 .precision = w1_DS18S20_precision, 186 .eeprom = w1_therm_eeprom 187 }, 188 { 189 .f = &w1_therm_family_DS18B20, 190 .convert = w1_DS18B20_convert_temp, 191 .precision = w1_DS18B20_precision, 192 .eeprom = w1_therm_eeprom 193 }, 194 { 195 .f = &w1_therm_family_DS28EA00, 196 .convert = w1_DS18B20_convert_temp, 197 .precision = w1_DS18S20_precision, 198 .eeprom = w1_therm_eeprom 199 }, 200 { 201 .f = &w1_therm_family_DS1825, 202 .convert = w1_DS18B20_convert_temp, 203 .precision = w1_DS18S20_precision, 204 .eeprom = w1_therm_eeprom 205 } 206 }; 207 208 static inline int w1_therm_eeprom(struct device *device) 209 { 210 struct w1_slave *sl = dev_to_w1_slave(device); 211 struct w1_master *dev = sl->master; 212 u8 rom[9], external_power; 213 int ret, max_trying = 10; 214 u8 *family_data = sl->family_data; 215 216 ret = mutex_lock_interruptible(&dev->bus_mutex); 217 if (ret != 0) 218 goto post_unlock; 219 220 if (!sl->family_data) { 221 ret = -ENODEV; 222 goto pre_unlock; 223 } 224 225 /* prevent the slave from going away in sleep */ 226 atomic_inc(THERM_REFCNT(family_data)); 227 memset(rom, 0, sizeof(rom)); 228 229 while (max_trying--) { 230 if (!w1_reset_select_slave(sl)) { 231 unsigned int tm = 10; 232 unsigned long sleep_rem; 233 234 /* check if in parasite mode */ 235 w1_write_8(dev, W1_READ_PSUPPLY); 236 external_power = w1_read_8(dev); 237 238 if (w1_reset_select_slave(sl)) 239 continue; 240 241 /* 10ms strong pullup/delay after the copy command */ 242 if (w1_strong_pullup == 2 || 243 (!external_power && w1_strong_pullup)) 244 w1_next_pullup(dev, tm); 245 246 w1_write_8(dev, W1_COPY_SCRATCHPAD); 247 248 if (external_power) { 249 mutex_unlock(&dev->bus_mutex); 250 251 sleep_rem = msleep_interruptible(tm); 252 if (sleep_rem != 0) { 253 ret = -EINTR; 254 goto post_unlock; 255 } 256 257 ret = mutex_lock_interruptible(&dev->bus_mutex); 258 if (ret != 0) 259 goto post_unlock; 260 } else if (!w1_strong_pullup) { 261 sleep_rem = msleep_interruptible(tm); 262 if (sleep_rem != 0) { 263 ret = -EINTR; 264 goto pre_unlock; 265 } 266 } 267 268 break; 269 } 270 } 271 272 pre_unlock: 273 mutex_unlock(&dev->bus_mutex); 274 275 post_unlock: 276 atomic_dec(THERM_REFCNT(family_data)); 277 return ret; 278 } 279 280 /* DS18S20 does not feature configuration register */ 281 static inline int w1_DS18S20_precision(struct device *device, int val) 282 { 283 return 0; 284 } 285 286 static inline int w1_DS18B20_precision(struct device *device, int val) 287 { 288 struct w1_slave *sl = dev_to_w1_slave(device); 289 struct w1_master *dev = sl->master; 290 u8 rom[9], crc; 291 int ret, max_trying = 10; 292 u8 *family_data = sl->family_data; 293 uint8_t precision_bits; 294 uint8_t mask = 0x60; 295 296 if (val > 12 || val < 9) { 297 pr_warn("Unsupported precision\n"); 298 return -1; 299 } 300 301 ret = mutex_lock_interruptible(&dev->bus_mutex); 302 if (ret != 0) 303 goto post_unlock; 304 305 if (!sl->family_data) { 306 ret = -ENODEV; 307 goto pre_unlock; 308 } 309 310 /* prevent the slave from going away in sleep */ 311 atomic_inc(THERM_REFCNT(family_data)); 312 memset(rom, 0, sizeof(rom)); 313 314 /* translate precision to bitmask (see datasheet page 9) */ 315 switch (val) { 316 case 9: 317 precision_bits = 0x00; 318 break; 319 case 10: 320 precision_bits = 0x20; 321 break; 322 case 11: 323 precision_bits = 0x40; 324 break; 325 case 12: 326 default: 327 precision_bits = 0x60; 328 break; 329 } 330 331 while (max_trying--) { 332 crc = 0; 333 334 if (!w1_reset_select_slave(sl)) { 335 int count = 0; 336 337 /* read values to only alter precision bits */ 338 w1_write_8(dev, W1_READ_SCRATCHPAD); 339 count = w1_read_block(dev, rom, 9); 340 if (count != 9) 341 dev_warn(device, "w1_read_block() returned %u instead of 9.\n", count); 342 343 crc = w1_calc_crc8(rom, 8); 344 if (rom[8] == crc) { 345 rom[4] = (rom[4] & ~mask) | (precision_bits & mask); 346 347 if (!w1_reset_select_slave(sl)) { 348 w1_write_8(dev, W1_WRITE_SCRATCHPAD); 349 w1_write_8(dev, rom[2]); 350 w1_write_8(dev, rom[3]); 351 w1_write_8(dev, rom[4]); 352 353 break; 354 } 355 } 356 } 357 } 358 359 pre_unlock: 360 mutex_unlock(&dev->bus_mutex); 361 362 post_unlock: 363 atomic_dec(THERM_REFCNT(family_data)); 364 return ret; 365 } 366 367 static inline int w1_DS18B20_convert_temp(u8 rom[9]) 368 { 369 s16 t = le16_to_cpup((__le16 *)rom); 370 371 return t*1000/16; 372 } 373 374 static inline int w1_DS18S20_convert_temp(u8 rom[9]) 375 { 376 int t, h; 377 378 if (!rom[7]) 379 return 0; 380 381 if (rom[1] == 0) 382 t = ((s32)rom[0] >> 1)*1000; 383 else 384 t = 1000*(-1*(s32)(0x100-rom[0]) >> 1); 385 386 t -= 250; 387 h = 1000*((s32)rom[7] - (s32)rom[6]); 388 h /= (s32)rom[7]; 389 t += h; 390 391 return t; 392 } 393 394 static inline int w1_convert_temp(u8 rom[9], u8 fid) 395 { 396 int i; 397 398 for (i = 0; i < ARRAY_SIZE(w1_therm_families); ++i) 399 if (w1_therm_families[i].f->fid == fid) 400 return w1_therm_families[i].convert(rom); 401 402 return 0; 403 } 404 405 static ssize_t w1_slave_store(struct device *device, 406 struct device_attribute *attr, const char *buf, 407 size_t size) 408 { 409 int val, ret; 410 struct w1_slave *sl = dev_to_w1_slave(device); 411 int i; 412 413 ret = kstrtoint(buf, 0, &val); 414 if (ret) 415 return ret; 416 417 for (i = 0; i < ARRAY_SIZE(w1_therm_families); ++i) { 418 if (w1_therm_families[i].f->fid == sl->family->fid) { 419 /* zero value indicates to write current configuration to eeprom */ 420 if (val == 0) 421 ret = w1_therm_families[i].eeprom(device); 422 else 423 ret = w1_therm_families[i].precision(device, val); 424 break; 425 } 426 } 427 return ret ? : size; 428 } 429 430 static ssize_t w1_slave_show(struct device *device, 431 struct device_attribute *attr, char *buf) 432 { 433 struct w1_slave *sl = dev_to_w1_slave(device); 434 struct w1_master *dev = sl->master; 435 u8 rom[9], crc, verdict, external_power; 436 int i, ret, max_trying = 10; 437 ssize_t c = PAGE_SIZE; 438 u8 *family_data = sl->family_data; 439 440 ret = mutex_lock_interruptible(&dev->bus_mutex); 441 if (ret != 0) 442 goto post_unlock; 443 444 if (!sl->family_data) { 445 ret = -ENODEV; 446 goto pre_unlock; 447 } 448 449 /* prevent the slave from going away in sleep */ 450 atomic_inc(THERM_REFCNT(family_data)); 451 memset(rom, 0, sizeof(rom)); 452 453 while (max_trying--) { 454 455 verdict = 0; 456 crc = 0; 457 458 if (!w1_reset_select_slave(sl)) { 459 int count = 0; 460 unsigned int tm = 750; 461 unsigned long sleep_rem; 462 463 w1_write_8(dev, W1_READ_PSUPPLY); 464 external_power = w1_read_8(dev); 465 466 if (w1_reset_select_slave(sl)) 467 continue; 468 469 /* 750ms strong pullup (or delay) after the convert */ 470 if (w1_strong_pullup == 2 || 471 (!external_power && w1_strong_pullup)) 472 w1_next_pullup(dev, tm); 473 474 w1_write_8(dev, W1_CONVERT_TEMP); 475 476 if (external_power) { 477 mutex_unlock(&dev->bus_mutex); 478 479 sleep_rem = msleep_interruptible(tm); 480 if (sleep_rem != 0) { 481 ret = -EINTR; 482 goto post_unlock; 483 } 484 485 ret = mutex_lock_interruptible(&dev->bus_mutex); 486 if (ret != 0) 487 goto post_unlock; 488 } else if (!w1_strong_pullup) { 489 sleep_rem = msleep_interruptible(tm); 490 if (sleep_rem != 0) { 491 ret = -EINTR; 492 goto pre_unlock; 493 } 494 } 495 496 if (!w1_reset_select_slave(sl)) { 497 498 w1_write_8(dev, W1_READ_SCRATCHPAD); 499 count = w1_read_block(dev, rom, 9); 500 if (count != 9) { 501 dev_warn(device, "w1_read_block() " 502 "returned %u instead of 9.\n", 503 count); 504 } 505 506 crc = w1_calc_crc8(rom, 8); 507 508 if (rom[8] == crc) 509 verdict = 1; 510 } 511 } 512 513 if (verdict) 514 break; 515 } 516 517 for (i = 0; i < 9; ++i) 518 c -= snprintf(buf + PAGE_SIZE - c, c, "%02x ", rom[i]); 519 c -= snprintf(buf + PAGE_SIZE - c, c, ": crc=%02x %s\n", 520 crc, (verdict) ? "YES" : "NO"); 521 if (verdict) 522 memcpy(family_data, rom, sizeof(rom)); 523 else 524 dev_warn(device, "Read failed CRC check\n"); 525 526 for (i = 0; i < 9; ++i) 527 c -= snprintf(buf + PAGE_SIZE - c, c, "%02x ", 528 ((u8 *)family_data)[i]); 529 530 c -= snprintf(buf + PAGE_SIZE - c, c, "t=%d\n", 531 w1_convert_temp(rom, sl->family->fid)); 532 ret = PAGE_SIZE - c; 533 534 pre_unlock: 535 mutex_unlock(&dev->bus_mutex); 536 537 post_unlock: 538 atomic_dec(THERM_REFCNT(family_data)); 539 return ret; 540 } 541 542 #define W1_42_CHAIN 0x99 543 #define W1_42_CHAIN_OFF 0x3C 544 #define W1_42_CHAIN_OFF_INV 0xC3 545 #define W1_42_CHAIN_ON 0x5A 546 #define W1_42_CHAIN_ON_INV 0xA5 547 #define W1_42_CHAIN_DONE 0x96 548 #define W1_42_CHAIN_DONE_INV 0x69 549 #define W1_42_COND_READ 0x0F 550 #define W1_42_SUCCESS_CONFIRM_BYTE 0xAA 551 #define W1_42_FINISHED_BYTE 0xFF 552 static ssize_t w1_seq_show(struct device *device, 553 struct device_attribute *attr, char *buf) 554 { 555 struct w1_slave *sl = dev_to_w1_slave(device); 556 ssize_t c = PAGE_SIZE; 557 int rv; 558 int i; 559 u8 ack; 560 u64 rn; 561 struct w1_reg_num *reg_num; 562 int seq = 0; 563 564 mutex_lock(&sl->master->bus_mutex); 565 /* Place all devices in CHAIN state */ 566 if (w1_reset_bus(sl->master)) 567 goto error; 568 w1_write_8(sl->master, W1_SKIP_ROM); 569 w1_write_8(sl->master, W1_42_CHAIN); 570 w1_write_8(sl->master, W1_42_CHAIN_ON); 571 w1_write_8(sl->master, W1_42_CHAIN_ON_INV); 572 msleep(sl->master->pullup_duration); 573 574 /* check for acknowledgment */ 575 ack = w1_read_8(sl->master); 576 if (ack != W1_42_SUCCESS_CONFIRM_BYTE) 577 goto error; 578 579 /* In case the bus fails to send 0xFF, limit*/ 580 for (i = 0; i <= 64; i++) { 581 if (w1_reset_bus(sl->master)) 582 goto error; 583 584 w1_write_8(sl->master, W1_42_COND_READ); 585 rv = w1_read_block(sl->master, (u8 *)&rn, 8); 586 reg_num = (struct w1_reg_num *) &rn; 587 if (reg_num->family == W1_42_FINISHED_BYTE) 588 break; 589 if (sl->reg_num.id == reg_num->id) 590 seq = i; 591 592 w1_write_8(sl->master, W1_42_CHAIN); 593 w1_write_8(sl->master, W1_42_CHAIN_DONE); 594 w1_write_8(sl->master, W1_42_CHAIN_DONE_INV); 595 w1_read_block(sl->master, &ack, sizeof(ack)); 596 597 /* check for acknowledgment */ 598 ack = w1_read_8(sl->master); 599 if (ack != W1_42_SUCCESS_CONFIRM_BYTE) 600 goto error; 601 602 } 603 604 /* Exit from CHAIN state */ 605 if (w1_reset_bus(sl->master)) 606 goto error; 607 w1_write_8(sl->master, W1_SKIP_ROM); 608 w1_write_8(sl->master, W1_42_CHAIN); 609 w1_write_8(sl->master, W1_42_CHAIN_OFF); 610 w1_write_8(sl->master, W1_42_CHAIN_OFF_INV); 611 612 /* check for acknowledgment */ 613 ack = w1_read_8(sl->master); 614 if (ack != W1_42_SUCCESS_CONFIRM_BYTE) 615 goto error; 616 mutex_unlock(&sl->master->bus_mutex); 617 618 c -= snprintf(buf + PAGE_SIZE - c, c, "%d\n", seq); 619 return PAGE_SIZE - c; 620 error: 621 mutex_unlock(&sl->master->bus_mutex); 622 return -EIO; 623 } 624 625 static int __init w1_therm_init(void) 626 { 627 int err, i; 628 629 for (i = 0; i < ARRAY_SIZE(w1_therm_families); ++i) { 630 err = w1_register_family(w1_therm_families[i].f); 631 if (err) 632 w1_therm_families[i].broken = 1; 633 } 634 635 return 0; 636 } 637 638 static void __exit w1_therm_fini(void) 639 { 640 int i; 641 642 for (i = 0; i < ARRAY_SIZE(w1_therm_families); ++i) 643 if (!w1_therm_families[i].broken) 644 w1_unregister_family(w1_therm_families[i].f); 645 } 646 647 module_init(w1_therm_init); 648 module_exit(w1_therm_fini); 649