1 /* 2 * ntc_thermistor.c - NTC Thermistors 3 * 4 * Copyright (C) 2010 Samsung Electronics 5 * MyungJoo Ham <myungjoo.ham@samsung.com> 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 23 #include <linux/slab.h> 24 #include <linux/module.h> 25 #include <linux/pm_runtime.h> 26 #include <linux/math64.h> 27 #include <linux/platform_device.h> 28 #include <linux/err.h> 29 #include <linux/of.h> 30 #include <linux/of_device.h> 31 32 #include <linux/platform_data/ntc_thermistor.h> 33 34 #include <linux/iio/iio.h> 35 #include <linux/iio/machine.h> 36 #include <linux/iio/driver.h> 37 #include <linux/iio/consumer.h> 38 39 #include <linux/hwmon.h> 40 #include <linux/hwmon-sysfs.h> 41 42 struct ntc_compensation { 43 int temp_c; 44 unsigned int ohm; 45 }; 46 47 /* Order matters, ntc_match references the entries by index */ 48 static const struct platform_device_id ntc_thermistor_id[] = { 49 { "ncp15wb473", TYPE_NCPXXWB473 }, 50 { "ncp18wb473", TYPE_NCPXXWB473 }, 51 { "ncp21wb473", TYPE_NCPXXWB473 }, 52 { "ncp03wb473", TYPE_NCPXXWB473 }, 53 { "ncp15wl333", TYPE_NCPXXWL333 }, 54 { "b57330v2103", TYPE_B57330V2103}, 55 { }, 56 }; 57 58 /* 59 * A compensation table should be sorted by the values of .ohm 60 * in descending order. 61 * The following compensation tables are from the specification of Murata NTC 62 * Thermistors Datasheet 63 */ 64 static const struct ntc_compensation ncpXXwb473[] = { 65 { .temp_c = -40, .ohm = 1747920 }, 66 { .temp_c = -35, .ohm = 1245428 }, 67 { .temp_c = -30, .ohm = 898485 }, 68 { .temp_c = -25, .ohm = 655802 }, 69 { .temp_c = -20, .ohm = 483954 }, 70 { .temp_c = -15, .ohm = 360850 }, 71 { .temp_c = -10, .ohm = 271697 }, 72 { .temp_c = -5, .ohm = 206463 }, 73 { .temp_c = 0, .ohm = 158214 }, 74 { .temp_c = 5, .ohm = 122259 }, 75 { .temp_c = 10, .ohm = 95227 }, 76 { .temp_c = 15, .ohm = 74730 }, 77 { .temp_c = 20, .ohm = 59065 }, 78 { .temp_c = 25, .ohm = 47000 }, 79 { .temp_c = 30, .ohm = 37643 }, 80 { .temp_c = 35, .ohm = 30334 }, 81 { .temp_c = 40, .ohm = 24591 }, 82 { .temp_c = 45, .ohm = 20048 }, 83 { .temp_c = 50, .ohm = 16433 }, 84 { .temp_c = 55, .ohm = 13539 }, 85 { .temp_c = 60, .ohm = 11209 }, 86 { .temp_c = 65, .ohm = 9328 }, 87 { .temp_c = 70, .ohm = 7798 }, 88 { .temp_c = 75, .ohm = 6544 }, 89 { .temp_c = 80, .ohm = 5518 }, 90 { .temp_c = 85, .ohm = 4674 }, 91 { .temp_c = 90, .ohm = 3972 }, 92 { .temp_c = 95, .ohm = 3388 }, 93 { .temp_c = 100, .ohm = 2902 }, 94 { .temp_c = 105, .ohm = 2494 }, 95 { .temp_c = 110, .ohm = 2150 }, 96 { .temp_c = 115, .ohm = 1860 }, 97 { .temp_c = 120, .ohm = 1615 }, 98 { .temp_c = 125, .ohm = 1406 }, 99 }; 100 static const struct ntc_compensation ncpXXwl333[] = { 101 { .temp_c = -40, .ohm = 1610154 }, 102 { .temp_c = -35, .ohm = 1130850 }, 103 { .temp_c = -30, .ohm = 802609 }, 104 { .temp_c = -25, .ohm = 575385 }, 105 { .temp_c = -20, .ohm = 416464 }, 106 { .temp_c = -15, .ohm = 304219 }, 107 { .temp_c = -10, .ohm = 224193 }, 108 { .temp_c = -5, .ohm = 166623 }, 109 { .temp_c = 0, .ohm = 124850 }, 110 { .temp_c = 5, .ohm = 94287 }, 111 { .temp_c = 10, .ohm = 71747 }, 112 { .temp_c = 15, .ohm = 54996 }, 113 { .temp_c = 20, .ohm = 42455 }, 114 { .temp_c = 25, .ohm = 33000 }, 115 { .temp_c = 30, .ohm = 25822 }, 116 { .temp_c = 35, .ohm = 20335 }, 117 { .temp_c = 40, .ohm = 16115 }, 118 { .temp_c = 45, .ohm = 12849 }, 119 { .temp_c = 50, .ohm = 10306 }, 120 { .temp_c = 55, .ohm = 8314 }, 121 { .temp_c = 60, .ohm = 6746 }, 122 { .temp_c = 65, .ohm = 5503 }, 123 { .temp_c = 70, .ohm = 4513 }, 124 { .temp_c = 75, .ohm = 3721 }, 125 { .temp_c = 80, .ohm = 3084 }, 126 { .temp_c = 85, .ohm = 2569 }, 127 { .temp_c = 90, .ohm = 2151 }, 128 { .temp_c = 95, .ohm = 1809 }, 129 { .temp_c = 100, .ohm = 1529 }, 130 { .temp_c = 105, .ohm = 1299 }, 131 { .temp_c = 110, .ohm = 1108 }, 132 { .temp_c = 115, .ohm = 949 }, 133 { .temp_c = 120, .ohm = 817 }, 134 { .temp_c = 125, .ohm = 707 }, 135 }; 136 137 /* 138 * The following compensation table is from the specification of EPCOS NTC 139 * Thermistors Datasheet 140 */ 141 static const struct ntc_compensation b57330v2103[] = { 142 { .temp_c = -40, .ohm = 190030 }, 143 { .temp_c = -35, .ohm = 145360 }, 144 { .temp_c = -30, .ohm = 112060 }, 145 { .temp_c = -25, .ohm = 87041 }, 146 { .temp_c = -20, .ohm = 68104 }, 147 { .temp_c = -15, .ohm = 53665 }, 148 { .temp_c = -10, .ohm = 42576 }, 149 { .temp_c = -5, .ohm = 34001 }, 150 { .temp_c = 0, .ohm = 27326 }, 151 { .temp_c = 5, .ohm = 22096 }, 152 { .temp_c = 10, .ohm = 17973 }, 153 { .temp_c = 15, .ohm = 14703 }, 154 { .temp_c = 20, .ohm = 12090 }, 155 { .temp_c = 25, .ohm = 10000 }, 156 { .temp_c = 30, .ohm = 8311 }, 157 { .temp_c = 35, .ohm = 6941 }, 158 { .temp_c = 40, .ohm = 5825 }, 159 { .temp_c = 45, .ohm = 4911 }, 160 { .temp_c = 50, .ohm = 4158 }, 161 { .temp_c = 55, .ohm = 3536 }, 162 { .temp_c = 60, .ohm = 3019 }, 163 { .temp_c = 65, .ohm = 2588 }, 164 { .temp_c = 70, .ohm = 2227 }, 165 { .temp_c = 75, .ohm = 1924 }, 166 { .temp_c = 80, .ohm = 1668 }, 167 { .temp_c = 85, .ohm = 1451 }, 168 { .temp_c = 90, .ohm = 1266 }, 169 { .temp_c = 95, .ohm = 1108 }, 170 { .temp_c = 100, .ohm = 973 }, 171 { .temp_c = 105, .ohm = 857 }, 172 { .temp_c = 110, .ohm = 757 }, 173 { .temp_c = 115, .ohm = 671 }, 174 { .temp_c = 120, .ohm = 596 }, 175 { .temp_c = 125, .ohm = 531 }, 176 }; 177 178 struct ntc_data { 179 struct device *hwmon_dev; 180 struct ntc_thermistor_platform_data *pdata; 181 const struct ntc_compensation *comp; 182 struct device *dev; 183 int n_comp; 184 char name[PLATFORM_NAME_SIZE]; 185 }; 186 187 #if defined(CONFIG_OF) && IS_ENABLED(CONFIG_IIO) 188 static int ntc_adc_iio_read(struct ntc_thermistor_platform_data *pdata) 189 { 190 struct iio_channel *channel = pdata->chan; 191 s64 result; 192 int val, ret; 193 194 ret = iio_read_channel_raw(channel, &val); 195 if (ret < 0) { 196 pr_err("read channel() error: %d\n", ret); 197 return ret; 198 } 199 200 /* unit: mV */ 201 result = pdata->pullup_uv * (s64) val; 202 result >>= 12; 203 204 return (int)result; 205 } 206 207 static const struct of_device_id ntc_match[] = { 208 { .compatible = "murata,ncp15wb473", 209 .data = &ntc_thermistor_id[0] }, 210 { .compatible = "murata,ncp18wb473", 211 .data = &ntc_thermistor_id[1] }, 212 { .compatible = "murata,ncp21wb473", 213 .data = &ntc_thermistor_id[2] }, 214 { .compatible = "murata,ncp03wb473", 215 .data = &ntc_thermistor_id[3] }, 216 { .compatible = "murata,ncp15wl333", 217 .data = &ntc_thermistor_id[4] }, 218 { .compatible = "epcos,b57330v2103", 219 .data = &ntc_thermistor_id[5]}, 220 221 /* Usage of vendor name "ntc" is deprecated */ 222 { .compatible = "ntc,ncp15wb473", 223 .data = &ntc_thermistor_id[0] }, 224 { .compatible = "ntc,ncp18wb473", 225 .data = &ntc_thermistor_id[1] }, 226 { .compatible = "ntc,ncp21wb473", 227 .data = &ntc_thermistor_id[2] }, 228 { .compatible = "ntc,ncp03wb473", 229 .data = &ntc_thermistor_id[3] }, 230 { .compatible = "ntc,ncp15wl333", 231 .data = &ntc_thermistor_id[4] }, 232 { }, 233 }; 234 MODULE_DEVICE_TABLE(of, ntc_match); 235 236 static struct ntc_thermistor_platform_data * 237 ntc_thermistor_parse_dt(struct platform_device *pdev) 238 { 239 struct iio_channel *chan; 240 struct device_node *np = pdev->dev.of_node; 241 struct ntc_thermistor_platform_data *pdata; 242 243 if (!np) 244 return NULL; 245 246 pdata = devm_kzalloc(&pdev->dev, sizeof(*pdata), GFP_KERNEL); 247 if (!pdata) 248 return ERR_PTR(-ENOMEM); 249 250 chan = iio_channel_get(&pdev->dev, NULL); 251 if (IS_ERR(chan)) 252 return ERR_CAST(chan); 253 254 if (of_property_read_u32(np, "pullup-uv", &pdata->pullup_uv)) 255 return ERR_PTR(-ENODEV); 256 if (of_property_read_u32(np, "pullup-ohm", &pdata->pullup_ohm)) 257 return ERR_PTR(-ENODEV); 258 if (of_property_read_u32(np, "pulldown-ohm", &pdata->pulldown_ohm)) 259 return ERR_PTR(-ENODEV); 260 261 if (of_find_property(np, "connected-positive", NULL)) 262 pdata->connect = NTC_CONNECTED_POSITIVE; 263 else /* status change should be possible if not always on. */ 264 pdata->connect = NTC_CONNECTED_GROUND; 265 266 pdata->chan = chan; 267 pdata->read_uv = ntc_adc_iio_read; 268 269 return pdata; 270 } 271 static void ntc_iio_channel_release(struct ntc_thermistor_platform_data *pdata) 272 { 273 if (pdata->chan) 274 iio_channel_release(pdata->chan); 275 } 276 #else 277 static struct ntc_thermistor_platform_data * 278 ntc_thermistor_parse_dt(struct platform_device *pdev) 279 { 280 return NULL; 281 } 282 283 #define ntc_match NULL 284 285 static void ntc_iio_channel_release(struct ntc_thermistor_platform_data *pdata) 286 { } 287 #endif 288 289 static inline u64 div64_u64_safe(u64 dividend, u64 divisor) 290 { 291 if (divisor == 0 && dividend == 0) 292 return 0; 293 if (divisor == 0) 294 return UINT_MAX; 295 return div64_u64(dividend, divisor); 296 } 297 298 static int get_ohm_of_thermistor(struct ntc_data *data, unsigned int uv) 299 { 300 struct ntc_thermistor_platform_data *pdata = data->pdata; 301 u64 mv = uv / 1000; 302 u64 pmv = pdata->pullup_uv / 1000; 303 u64 n, puo, pdo; 304 puo = pdata->pullup_ohm; 305 pdo = pdata->pulldown_ohm; 306 307 if (mv == 0) { 308 if (pdata->connect == NTC_CONNECTED_POSITIVE) 309 return INT_MAX; 310 return 0; 311 } 312 if (mv >= pmv) 313 return (pdata->connect == NTC_CONNECTED_POSITIVE) ? 314 0 : INT_MAX; 315 316 if (pdata->connect == NTC_CONNECTED_POSITIVE && puo == 0) 317 n = div64_u64_safe(pdo * (pmv - mv), mv); 318 else if (pdata->connect == NTC_CONNECTED_GROUND && pdo == 0) 319 n = div64_u64_safe(puo * mv, pmv - mv); 320 else if (pdata->connect == NTC_CONNECTED_POSITIVE) 321 n = div64_u64_safe(pdo * puo * (pmv - mv), 322 puo * mv - pdo * (pmv - mv)); 323 else 324 n = div64_u64_safe(pdo * puo * mv, pdo * (pmv - mv) - puo * mv); 325 326 if (n > INT_MAX) 327 n = INT_MAX; 328 return n; 329 } 330 331 static void lookup_comp(struct ntc_data *data, unsigned int ohm, 332 int *i_low, int *i_high) 333 { 334 int start, end, mid; 335 336 /* 337 * Handle special cases: Resistance is higher than or equal to 338 * resistance in first table entry, or resistance is lower or equal 339 * to resistance in last table entry. 340 * In these cases, return i_low == i_high, either pointing to the 341 * beginning or to the end of the table depending on the condition. 342 */ 343 if (ohm >= data->comp[0].ohm) { 344 *i_low = 0; 345 *i_high = 0; 346 return; 347 } 348 if (ohm <= data->comp[data->n_comp - 1].ohm) { 349 *i_low = data->n_comp - 1; 350 *i_high = data->n_comp - 1; 351 return; 352 } 353 354 /* Do a binary search on compensation table */ 355 start = 0; 356 end = data->n_comp; 357 while (start < end) { 358 mid = start + (end - start) / 2; 359 /* 360 * start <= mid < end 361 * data->comp[start].ohm > ohm >= data->comp[end].ohm 362 * 363 * We could check for "ohm == data->comp[mid].ohm" here, but 364 * that is a quite unlikely condition, and we would have to 365 * check again after updating start. Check it at the end instead 366 * for simplicity. 367 */ 368 if (ohm >= data->comp[mid].ohm) { 369 end = mid; 370 } else { 371 start = mid + 1; 372 /* 373 * ohm >= data->comp[start].ohm might be true here, 374 * since we set start to mid + 1. In that case, we are 375 * done. We could keep going, but the condition is quite 376 * likely to occur, so it is worth checking for it. 377 */ 378 if (ohm >= data->comp[start].ohm) 379 end = start; 380 } 381 /* 382 * start <= end 383 * data->comp[start].ohm >= ohm >= data->comp[end].ohm 384 */ 385 } 386 /* 387 * start == end 388 * ohm >= data->comp[end].ohm 389 */ 390 *i_low = end; 391 if (ohm == data->comp[end].ohm) 392 *i_high = end; 393 else 394 *i_high = end - 1; 395 } 396 397 static int get_temp_mc(struct ntc_data *data, unsigned int ohm) 398 { 399 int low, high; 400 int temp; 401 402 lookup_comp(data, ohm, &low, &high); 403 if (low == high) { 404 /* Unable to use linear approximation */ 405 temp = data->comp[low].temp_c * 1000; 406 } else { 407 temp = data->comp[low].temp_c * 1000 + 408 ((data->comp[high].temp_c - data->comp[low].temp_c) * 409 1000 * ((int)ohm - (int)data->comp[low].ohm)) / 410 ((int)data->comp[high].ohm - (int)data->comp[low].ohm); 411 } 412 return temp; 413 } 414 415 static int ntc_thermistor_get_ohm(struct ntc_data *data) 416 { 417 int read_uv; 418 419 if (data->pdata->read_ohm) 420 return data->pdata->read_ohm(); 421 422 if (data->pdata->read_uv) { 423 read_uv = data->pdata->read_uv(data->pdata); 424 if (read_uv < 0) 425 return read_uv; 426 return get_ohm_of_thermistor(data, read_uv); 427 } 428 return -EINVAL; 429 } 430 431 static ssize_t ntc_show_name(struct device *dev, 432 struct device_attribute *attr, char *buf) 433 { 434 struct ntc_data *data = dev_get_drvdata(dev); 435 436 return sprintf(buf, "%s\n", data->name); 437 } 438 439 static ssize_t ntc_show_type(struct device *dev, 440 struct device_attribute *attr, char *buf) 441 { 442 return sprintf(buf, "4\n"); 443 } 444 445 static ssize_t ntc_show_temp(struct device *dev, 446 struct device_attribute *attr, char *buf) 447 { 448 struct ntc_data *data = dev_get_drvdata(dev); 449 int ohm; 450 451 ohm = ntc_thermistor_get_ohm(data); 452 if (ohm < 0) 453 return ohm; 454 455 return sprintf(buf, "%d\n", get_temp_mc(data, ohm)); 456 } 457 458 static SENSOR_DEVICE_ATTR(temp1_type, S_IRUGO, ntc_show_type, NULL, 0); 459 static SENSOR_DEVICE_ATTR(temp1_input, S_IRUGO, ntc_show_temp, NULL, 0); 460 static DEVICE_ATTR(name, S_IRUGO, ntc_show_name, NULL); 461 462 static struct attribute *ntc_attributes[] = { 463 &dev_attr_name.attr, 464 &sensor_dev_attr_temp1_type.dev_attr.attr, 465 &sensor_dev_attr_temp1_input.dev_attr.attr, 466 NULL, 467 }; 468 469 static const struct attribute_group ntc_attr_group = { 470 .attrs = ntc_attributes, 471 }; 472 473 static int ntc_thermistor_probe(struct platform_device *pdev) 474 { 475 const struct of_device_id *of_id = 476 of_match_device(of_match_ptr(ntc_match), &pdev->dev); 477 const struct platform_device_id *pdev_id; 478 struct ntc_thermistor_platform_data *pdata; 479 struct ntc_data *data; 480 int ret; 481 482 pdata = ntc_thermistor_parse_dt(pdev); 483 if (IS_ERR(pdata)) 484 return PTR_ERR(pdata); 485 else if (pdata == NULL) 486 pdata = dev_get_platdata(&pdev->dev); 487 488 if (!pdata) { 489 dev_err(&pdev->dev, "No platform init data supplied.\n"); 490 return -ENODEV; 491 } 492 493 /* Either one of the two is required. */ 494 if (!pdata->read_uv && !pdata->read_ohm) { 495 dev_err(&pdev->dev, 496 "Both read_uv and read_ohm missing. Need either one of the two.\n"); 497 return -EINVAL; 498 } 499 500 if (pdata->read_uv && pdata->read_ohm) { 501 dev_warn(&pdev->dev, 502 "Only one of read_uv and read_ohm is needed; ignoring read_uv.\n"); 503 pdata->read_uv = NULL; 504 } 505 506 if (pdata->read_uv && (pdata->pullup_uv == 0 || 507 (pdata->pullup_ohm == 0 && pdata->connect == 508 NTC_CONNECTED_GROUND) || 509 (pdata->pulldown_ohm == 0 && pdata->connect == 510 NTC_CONNECTED_POSITIVE) || 511 (pdata->connect != NTC_CONNECTED_POSITIVE && 512 pdata->connect != NTC_CONNECTED_GROUND))) { 513 dev_err(&pdev->dev, 514 "Required data to use read_uv not supplied.\n"); 515 return -EINVAL; 516 } 517 518 data = devm_kzalloc(&pdev->dev, sizeof(struct ntc_data), GFP_KERNEL); 519 if (!data) 520 return -ENOMEM; 521 522 pdev_id = of_id ? of_id->data : platform_get_device_id(pdev); 523 524 data->dev = &pdev->dev; 525 data->pdata = pdata; 526 strlcpy(data->name, pdev_id->name, sizeof(data->name)); 527 528 switch (pdev_id->driver_data) { 529 case TYPE_NCPXXWB473: 530 data->comp = ncpXXwb473; 531 data->n_comp = ARRAY_SIZE(ncpXXwb473); 532 break; 533 case TYPE_NCPXXWL333: 534 data->comp = ncpXXwl333; 535 data->n_comp = ARRAY_SIZE(ncpXXwl333); 536 break; 537 case TYPE_B57330V2103: 538 data->comp = b57330v2103; 539 data->n_comp = ARRAY_SIZE(b57330v2103); 540 break; 541 default: 542 dev_err(&pdev->dev, "Unknown device type: %lu(%s)\n", 543 pdev_id->driver_data, pdev_id->name); 544 return -EINVAL; 545 } 546 547 platform_set_drvdata(pdev, data); 548 549 ret = sysfs_create_group(&data->dev->kobj, &ntc_attr_group); 550 if (ret) { 551 dev_err(data->dev, "unable to create sysfs files\n"); 552 return ret; 553 } 554 555 data->hwmon_dev = hwmon_device_register(data->dev); 556 if (IS_ERR(data->hwmon_dev)) { 557 dev_err(data->dev, "unable to register as hwmon device.\n"); 558 ret = PTR_ERR(data->hwmon_dev); 559 goto err_after_sysfs; 560 } 561 562 dev_info(&pdev->dev, "Thermistor type: %s successfully probed.\n", 563 pdev_id->name); 564 565 return 0; 566 err_after_sysfs: 567 sysfs_remove_group(&data->dev->kobj, &ntc_attr_group); 568 ntc_iio_channel_release(pdata); 569 return ret; 570 } 571 572 static int ntc_thermistor_remove(struct platform_device *pdev) 573 { 574 struct ntc_data *data = platform_get_drvdata(pdev); 575 struct ntc_thermistor_platform_data *pdata = data->pdata; 576 577 hwmon_device_unregister(data->hwmon_dev); 578 sysfs_remove_group(&data->dev->kobj, &ntc_attr_group); 579 ntc_iio_channel_release(pdata); 580 581 return 0; 582 } 583 584 static struct platform_driver ntc_thermistor_driver = { 585 .driver = { 586 .name = "ntc-thermistor", 587 .owner = THIS_MODULE, 588 .of_match_table = of_match_ptr(ntc_match), 589 }, 590 .probe = ntc_thermistor_probe, 591 .remove = ntc_thermistor_remove, 592 .id_table = ntc_thermistor_id, 593 }; 594 595 module_platform_driver(ntc_thermistor_driver); 596 597 MODULE_DESCRIPTION("NTC Thermistor Driver"); 598 MODULE_AUTHOR("MyungJoo Ham <myungjoo.ham@samsung.com>"); 599 MODULE_LICENSE("GPL"); 600 MODULE_ALIAS("platform:ntc-thermistor"); 601