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 while(refcnt) { 85 msleep(1000); 86 refcnt = atomic_read(THERM_REFCNT(sl->family_data)); 87 } 88 kfree(sl->family_data); 89 sl->family_data = NULL; 90 } 91 92 static ssize_t w1_slave_show(struct device *device, 93 struct device_attribute *attr, char *buf); 94 95 static ssize_t w1_slave_store(struct device *device, 96 struct device_attribute *attr, const char *buf, size_t size); 97 98 static ssize_t w1_seq_show(struct device *device, 99 struct device_attribute *attr, char *buf); 100 101 static DEVICE_ATTR_RW(w1_slave); 102 static DEVICE_ATTR_RO(w1_seq); 103 104 static struct attribute *w1_therm_attrs[] = { 105 &dev_attr_w1_slave.attr, 106 NULL, 107 }; 108 109 static struct attribute *w1_ds28ea00_attrs[] = { 110 &dev_attr_w1_slave.attr, 111 &dev_attr_w1_seq.attr, 112 NULL, 113 }; 114 ATTRIBUTE_GROUPS(w1_therm); 115 ATTRIBUTE_GROUPS(w1_ds28ea00); 116 117 static struct w1_family_ops w1_therm_fops = { 118 .add_slave = w1_therm_add_slave, 119 .remove_slave = w1_therm_remove_slave, 120 .groups = w1_therm_groups, 121 }; 122 123 static struct w1_family_ops w1_ds28ea00_fops = { 124 .add_slave = w1_therm_add_slave, 125 .remove_slave = w1_therm_remove_slave, 126 .groups = w1_ds28ea00_groups, 127 }; 128 129 static struct w1_family w1_therm_family_DS18S20 = { 130 .fid = W1_THERM_DS18S20, 131 .fops = &w1_therm_fops, 132 }; 133 134 static struct w1_family w1_therm_family_DS18B20 = { 135 .fid = W1_THERM_DS18B20, 136 .fops = &w1_therm_fops, 137 }; 138 139 static struct w1_family w1_therm_family_DS1822 = { 140 .fid = W1_THERM_DS1822, 141 .fops = &w1_therm_fops, 142 }; 143 144 static struct w1_family w1_therm_family_DS28EA00 = { 145 .fid = W1_THERM_DS28EA00, 146 .fops = &w1_ds28ea00_fops, 147 }; 148 149 static struct w1_family w1_therm_family_DS1825 = { 150 .fid = W1_THERM_DS1825, 151 .fops = &w1_therm_fops, 152 }; 153 154 struct w1_therm_family_converter 155 { 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 if ((count = w1_read_block(dev, rom, 9)) != 9) 340 dev_warn(device, "w1_read_block() returned %u instead of 9.\n", count); 341 342 crc = w1_calc_crc8(rom, 8); 343 if (rom[8] == crc) { 344 rom[4] = (rom[4] & ~mask) | (precision_bits & mask); 345 346 if (!w1_reset_select_slave(sl)) { 347 w1_write_8(dev, W1_WRITE_SCRATCHPAD); 348 w1_write_8(dev, rom[2]); 349 w1_write_8(dev, rom[3]); 350 w1_write_8(dev, rom[4]); 351 352 break; 353 } 354 } 355 } 356 } 357 358 pre_unlock: 359 mutex_unlock(&dev->bus_mutex); 360 361 post_unlock: 362 atomic_dec(THERM_REFCNT(family_data)); 363 return ret; 364 } 365 366 static inline int w1_DS18B20_convert_temp(u8 rom[9]) 367 { 368 s16 t = le16_to_cpup((__le16 *)rom); 369 return t*1000/16; 370 } 371 372 static inline int w1_DS18S20_convert_temp(u8 rom[9]) 373 { 374 int t, h; 375 376 if (!rom[7]) 377 return 0; 378 379 if (rom[1] == 0) 380 t = ((s32)rom[0] >> 1)*1000; 381 else 382 t = 1000*(-1*(s32)(0x100-rom[0]) >> 1); 383 384 t -= 250; 385 h = 1000*((s32)rom[7] - (s32)rom[6]); 386 h /= (s32)rom[7]; 387 t += h; 388 389 return t; 390 } 391 392 static inline int w1_convert_temp(u8 rom[9], u8 fid) 393 { 394 int i; 395 396 for (i = 0; i < ARRAY_SIZE(w1_therm_families); ++i) 397 if (w1_therm_families[i].f->fid == fid) 398 return w1_therm_families[i].convert(rom); 399 400 return 0; 401 } 402 403 static ssize_t w1_slave_store(struct device *device, 404 struct device_attribute *attr, const char *buf, 405 size_t size) 406 { 407 int val, ret; 408 struct w1_slave *sl = dev_to_w1_slave(device); 409 int i; 410 411 ret = kstrtoint(buf, 0, &val); 412 if (ret) 413 return ret; 414 415 for (i = 0; i < ARRAY_SIZE(w1_therm_families); ++i) { 416 if (w1_therm_families[i].f->fid == sl->family->fid) { 417 /* zero value indicates to write current configuration to eeprom */ 418 if (0 == val) 419 ret = w1_therm_families[i].eeprom(device); 420 else 421 ret = w1_therm_families[i].precision(device, val); 422 break; 423 } 424 } 425 return ret ? : size; 426 } 427 428 static ssize_t w1_slave_show(struct device *device, 429 struct device_attribute *attr, char *buf) 430 { 431 struct w1_slave *sl = dev_to_w1_slave(device); 432 struct w1_master *dev = sl->master; 433 u8 rom[9], crc, verdict, external_power; 434 int i, ret, max_trying = 10; 435 ssize_t c = PAGE_SIZE; 436 u8 *family_data = sl->family_data; 437 438 ret = mutex_lock_interruptible(&dev->bus_mutex); 439 if (ret != 0) 440 goto post_unlock; 441 442 if(!sl->family_data) 443 { 444 ret = -ENODEV; 445 goto pre_unlock; 446 } 447 448 /* prevent the slave from going away in sleep */ 449 atomic_inc(THERM_REFCNT(family_data)); 450 memset(rom, 0, sizeof(rom)); 451 452 while (max_trying--) { 453 454 verdict = 0; 455 crc = 0; 456 457 if (!w1_reset_select_slave(sl)) { 458 int count = 0; 459 unsigned int tm = 750; 460 unsigned long sleep_rem; 461 462 w1_write_8(dev, W1_READ_PSUPPLY); 463 external_power = w1_read_8(dev); 464 465 if (w1_reset_select_slave(sl)) 466 continue; 467 468 /* 750ms strong pullup (or delay) after the convert */ 469 if (w1_strong_pullup == 2 || 470 (!external_power && w1_strong_pullup)) 471 w1_next_pullup(dev, tm); 472 473 w1_write_8(dev, W1_CONVERT_TEMP); 474 475 if (external_power) { 476 mutex_unlock(&dev->bus_mutex); 477 478 sleep_rem = msleep_interruptible(tm); 479 if (sleep_rem != 0) { 480 ret = -EINTR; 481 goto post_unlock; 482 } 483 484 ret = mutex_lock_interruptible(&dev->bus_mutex); 485 if (ret != 0) 486 goto post_unlock; 487 } else if (!w1_strong_pullup) { 488 sleep_rem = msleep_interruptible(tm); 489 if (sleep_rem != 0) { 490 ret = -EINTR; 491 goto pre_unlock; 492 } 493 } 494 495 if (!w1_reset_select_slave(sl)) { 496 497 w1_write_8(dev, W1_READ_SCRATCHPAD); 498 if ((count = w1_read_block(dev, rom, 9)) != 9) { 499 dev_warn(device, "w1_read_block() " 500 "returned %u instead of 9.\n", 501 count); 502 } 503 504 crc = w1_calc_crc8(rom, 8); 505 506 if (rom[8] == crc) 507 verdict = 1; 508 } 509 } 510 511 if (verdict) 512 break; 513 } 514 515 for (i = 0; i < 9; ++i) 516 c -= snprintf(buf + PAGE_SIZE - c, c, "%02x ", rom[i]); 517 c -= snprintf(buf + PAGE_SIZE - c, c, ": crc=%02x %s\n", 518 crc, (verdict) ? "YES" : "NO"); 519 if (verdict) 520 memcpy(family_data, rom, sizeof(rom)); 521 else 522 dev_warn(device, "Read failed CRC check\n"); 523 524 for (i = 0; i < 9; ++i) 525 c -= snprintf(buf + PAGE_SIZE - c, c, "%02x ", 526 ((u8 *)family_data)[i]); 527 528 c -= snprintf(buf + PAGE_SIZE - c, c, "t=%d\n", 529 w1_convert_temp(rom, sl->family->fid)); 530 ret = PAGE_SIZE - c; 531 532 pre_unlock: 533 mutex_unlock(&dev->bus_mutex); 534 535 post_unlock: 536 atomic_dec(THERM_REFCNT(family_data)); 537 return ret; 538 } 539 540 #define W1_42_CHAIN 0x99 541 #define W1_42_CHAIN_OFF 0x3C 542 #define W1_42_CHAIN_OFF_INV 0xC3 543 #define W1_42_CHAIN_ON 0x5A 544 #define W1_42_CHAIN_ON_INV 0xA5 545 #define W1_42_CHAIN_DONE 0x96 546 #define W1_42_CHAIN_DONE_INV 0x69 547 #define W1_42_COND_READ 0x0F 548 #define W1_42_SUCCESS_CONFIRM_BYTE 0xAA 549 #define W1_42_FINISHED_BYTE 0xFF 550 static ssize_t w1_seq_show(struct device *device, 551 struct device_attribute *attr, char *buf) 552 { 553 struct w1_slave *sl = dev_to_w1_slave(device); 554 ssize_t c = PAGE_SIZE; 555 int rv; 556 int i; 557 u8 ack; 558 u64 rn; 559 struct w1_reg_num *reg_num; 560 int seq = 0; 561 562 mutex_lock(&sl->master->bus_mutex); 563 /* Place all devices in CHAIN state */ 564 if (w1_reset_bus(sl->master)) 565 goto error; 566 w1_write_8(sl->master, W1_SKIP_ROM); 567 w1_write_8(sl->master, W1_42_CHAIN); 568 w1_write_8(sl->master, W1_42_CHAIN_ON); 569 w1_write_8(sl->master, W1_42_CHAIN_ON_INV); 570 msleep(sl->master->pullup_duration); 571 572 /* check for acknowledgment */ 573 ack = w1_read_8(sl->master); 574 if (ack != W1_42_SUCCESS_CONFIRM_BYTE) 575 goto error; 576 577 /* In case the bus fails to send 0xFF, limit*/ 578 for (i = 0; i <= 64; i++) { 579 if (w1_reset_bus(sl->master)) 580 goto error; 581 582 w1_write_8(sl->master, W1_42_COND_READ); 583 rv = w1_read_block(sl->master, (u8 *)&rn, 8); 584 reg_num = (struct w1_reg_num *) &rn; 585 if (reg_num->family == W1_42_FINISHED_BYTE) 586 break; 587 if (sl->reg_num.id == reg_num->id) 588 seq = i; 589 590 w1_write_8(sl->master, W1_42_CHAIN); 591 w1_write_8(sl->master, W1_42_CHAIN_DONE); 592 w1_write_8(sl->master, W1_42_CHAIN_DONE_INV); 593 w1_read_block(sl->master, &ack, sizeof(ack)); 594 595 /* check for acknowledgment */ 596 ack = w1_read_8(sl->master); 597 if (ack != W1_42_SUCCESS_CONFIRM_BYTE) 598 goto error; 599 600 } 601 602 /* Exit from CHAIN state */ 603 if (w1_reset_bus(sl->master)) 604 goto error; 605 w1_write_8(sl->master, W1_SKIP_ROM); 606 w1_write_8(sl->master, W1_42_CHAIN); 607 w1_write_8(sl->master, W1_42_CHAIN_OFF); 608 w1_write_8(sl->master, W1_42_CHAIN_OFF_INV); 609 610 /* check for acknowledgment */ 611 ack = w1_read_8(sl->master); 612 if (ack != W1_42_SUCCESS_CONFIRM_BYTE) 613 goto error; 614 mutex_unlock(&sl->master->bus_mutex); 615 616 c -= snprintf(buf + PAGE_SIZE - c, c, "%d\n", seq); 617 return PAGE_SIZE - c; 618 error: 619 mutex_unlock(&sl->master->bus_mutex); 620 return -EIO; 621 } 622 623 static int __init w1_therm_init(void) 624 { 625 int err, i; 626 627 for (i = 0; i < ARRAY_SIZE(w1_therm_families); ++i) { 628 err = w1_register_family(w1_therm_families[i].f); 629 if (err) 630 w1_therm_families[i].broken = 1; 631 } 632 633 return 0; 634 } 635 636 static void __exit w1_therm_fini(void) 637 { 638 int i; 639 640 for (i = 0; i < ARRAY_SIZE(w1_therm_families); ++i) 641 if (!w1_therm_families[i].broken) 642 w1_unregister_family(w1_therm_families[i].f); 643 } 644 645 module_init(w1_therm_init); 646 module_exit(w1_therm_fini); 647