drivers/hwmon/ntc_thermistor.c

   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 #include <linux/thermal.h>
  42
  43 struct ntc_compensation {
  44         int             temp_c;
  45         unsigned int    ohm;
  46 };
  47
  48 /* Order matters, ntc_match references the entries by index */
  49 static const struct platform_device_id ntc_thermistor_id[] = {
  50         { "ncp15wb473", TYPE_NCPXXWB473 },
  51         { "ncp18wb473", TYPE_NCPXXWB473 },
  52         { "ncp21wb473", TYPE_NCPXXWB473 },
  53         { "ncp03wb473", TYPE_NCPXXWB473 },
  54         { "ncp15wl333", TYPE_NCPXXWL333 },
  55         { "b57330v2103", TYPE_B57330V2103},
  56         { },
  57 };
  58
  59 /*
  60  * A compensation table should be sorted by the values of .ohm
  61  * in descending order.
  62  * The following compensation tables are from the specification of Murata NTC
  63  * Thermistors Datasheet
  64  */
  65 static const struct ntc_compensation ncpXXwb473[] = {
  66         { .temp_c       = -40, .ohm     = 1747920 },
  67         { .temp_c       = -35, .ohm     = 1245428 },
  68         { .temp_c       = -30, .ohm     = 898485 },
  69         { .temp_c       = -25, .ohm     = 655802 },
  70         { .temp_c       = -20, .ohm     = 483954 },
  71         { .temp_c       = -15, .ohm     = 360850 },
  72         { .temp_c       = -10, .ohm     = 271697 },
  73         { .temp_c       = -5, .ohm      = 206463 },
  74         { .temp_c       = 0, .ohm       = 158214 },
  75         { .temp_c       = 5, .ohm       = 122259 },
  76         { .temp_c       = 10, .ohm      = 95227 },
  77         { .temp_c       = 15, .ohm      = 74730 },
  78         { .temp_c       = 20, .ohm      = 59065 },
  79         { .temp_c       = 25, .ohm      = 47000 },
  80         { .temp_c       = 30, .ohm      = 37643 },
  81         { .temp_c       = 35, .ohm      = 30334 },
  82         { .temp_c       = 40, .ohm      = 24591 },
  83         { .temp_c       = 45, .ohm      = 20048 },
  84         { .temp_c       = 50, .ohm      = 16433 },
  85         { .temp_c       = 55, .ohm      = 13539 },
  86         { .temp_c       = 60, .ohm      = 11209 },
  87         { .temp_c       = 65, .ohm      = 9328 },
  88         { .temp_c       = 70, .ohm      = 7798 },
  89         { .temp_c       = 75, .ohm      = 6544 },
  90         { .temp_c       = 80, .ohm      = 5518 },
  91         { .temp_c       = 85, .ohm      = 4674 },
  92         { .temp_c       = 90, .ohm      = 3972 },
  93         { .temp_c       = 95, .ohm      = 3388 },
  94         { .temp_c       = 100, .ohm     = 2902 },
  95         { .temp_c       = 105, .ohm     = 2494 },
  96         { .temp_c       = 110, .ohm     = 2150 },
  97         { .temp_c       = 115, .ohm     = 1860 },
  98         { .temp_c       = 120, .ohm     = 1615 },
  99         { .temp_c       = 125, .ohm     = 1406 },
 100 };
 101 static const struct ntc_compensation ncpXXwl333[] = {
 102         { .temp_c       = -40, .ohm     = 1610154 },
 103         { .temp_c       = -35, .ohm     = 1130850 },
 104         { .temp_c       = -30, .ohm     = 802609 },
 105         { .temp_c       = -25, .ohm     = 575385 },
 106         { .temp_c       = -20, .ohm     = 416464 },
 107         { .temp_c       = -15, .ohm     = 304219 },
 108         { .temp_c       = -10, .ohm     = 224193 },
 109         { .temp_c       = -5, .ohm      = 166623 },
 110         { .temp_c       = 0, .ohm       = 124850 },
 111         { .temp_c       = 5, .ohm       = 94287 },
 112         { .temp_c       = 10, .ohm      = 71747 },
 113         { .temp_c       = 15, .ohm      = 54996 },
 114         { .temp_c       = 20, .ohm      = 42455 },
 115         { .temp_c       = 25, .ohm      = 33000 },
 116         { .temp_c       = 30, .ohm      = 25822 },
 117         { .temp_c       = 35, .ohm      = 20335 },
 118         { .temp_c       = 40, .ohm      = 16115 },
 119         { .temp_c       = 45, .ohm      = 12849 },
 120         { .temp_c       = 50, .ohm      = 10306 },
 121         { .temp_c       = 55, .ohm      = 8314 },
 122         { .temp_c       = 60, .ohm      = 6746 },
 123         { .temp_c       = 65, .ohm      = 5503 },
 124         { .temp_c       = 70, .ohm      = 4513 },
 125         { .temp_c       = 75, .ohm      = 3721 },
 126         { .temp_c       = 80, .ohm      = 3084 },
 127         { .temp_c       = 85, .ohm      = 2569 },
 128         { .temp_c       = 90, .ohm      = 2151 },
 129         { .temp_c       = 95, .ohm      = 1809 },
 130         { .temp_c       = 100, .ohm     = 1529 },
 131         { .temp_c       = 105, .ohm     = 1299 },
 132         { .temp_c       = 110, .ohm     = 1108 },
 133         { .temp_c       = 115, .ohm     = 949 },
 134         { .temp_c       = 120, .ohm     = 817 },
 135         { .temp_c       = 125, .ohm     = 707 },
 136 };
 137
 138 /*
 139  * The following compensation table is from the specification of EPCOS NTC
 140  * Thermistors Datasheet
 141  */
 142 static const struct ntc_compensation b57330v2103[] = {
 143         { .temp_c       = -40, .ohm     = 190030 },
 144         { .temp_c       = -35, .ohm     = 145360 },
 145         { .temp_c       = -30, .ohm     = 112060 },
 146         { .temp_c       = -25, .ohm     = 87041 },
 147         { .temp_c       = -20, .ohm     = 68104 },
 148         { .temp_c       = -15, .ohm     = 53665 },
 149         { .temp_c       = -10, .ohm     = 42576 },
 150         { .temp_c       = -5, .ohm      = 34001 },
 151         { .temp_c       = 0, .ohm       = 27326 },
 152         { .temp_c       = 5, .ohm       = 22096 },
 153         { .temp_c       = 10, .ohm      = 17973 },
 154         { .temp_c       = 15, .ohm      = 14703 },
 155         { .temp_c       = 20, .ohm      = 12090 },
 156         { .temp_c       = 25, .ohm      = 10000 },
 157         { .temp_c       = 30, .ohm      = 8311 },
 158         { .temp_c       = 35, .ohm      = 6941 },
 159         { .temp_c       = 40, .ohm      = 5825 },
 160         { .temp_c       = 45, .ohm      = 4911 },
 161         { .temp_c       = 50, .ohm      = 4158 },
 162         { .temp_c       = 55, .ohm      = 3536 },
 163         { .temp_c       = 60, .ohm      = 3019 },
 164         { .temp_c       = 65, .ohm      = 2588 },
 165         { .temp_c       = 70, .ohm      = 2227 },
 166         { .temp_c       = 75, .ohm      = 1924 },
 167         { .temp_c       = 80, .ohm      = 1668 },
 168         { .temp_c       = 85, .ohm      = 1451 },
 169         { .temp_c       = 90, .ohm      = 1266 },
 170         { .temp_c       = 95, .ohm      = 1108 },
 171         { .temp_c       = 100, .ohm     = 973 },
 172         { .temp_c       = 105, .ohm     = 857 },
 173         { .temp_c       = 110, .ohm     = 757 },
 174         { .temp_c       = 115, .ohm     = 671 },
 175         { .temp_c       = 120, .ohm     = 596 },
 176         { .temp_c       = 125, .ohm     = 531 },
 177 };
 178
 179 struct ntc_data {
 180         struct device *hwmon_dev;
 181         struct ntc_thermistor_platform_data *pdata;
 182         const struct ntc_compensation *comp;
 183         struct device *dev;
 184         int n_comp;
 185         char name[PLATFORM_NAME_SIZE];
 186         struct thermal_zone_device *tz;
 187 };
 188
 189 #if defined(CONFIG_OF) && IS_ENABLED(CONFIG_IIO)
 190 static int ntc_adc_iio_read(struct ntc_thermistor_platform_data *pdata)
 191 {
 192         struct iio_channel *channel = pdata->chan;
 193         s64 result;
 194         int val, ret;
 195
 196         ret = iio_read_channel_raw(channel, &val);
 197         if (ret < 0) {
 198                 pr_err("read channel() error: %d\n", ret);
 199                 return ret;
 200         }
 201
 202         /* unit: mV */
 203         result = pdata->pullup_uv * (s64) val;
 204         result >>= 12;
 205
 206         return (int)result;
 207 }
 208
 209 static const struct of_device_id ntc_match[] = {
 210         { .compatible = "murata,ncp15wb473",
 211                 .data = &ntc_thermistor_id[0] },
 212         { .compatible = "murata,ncp18wb473",
 213                 .data = &ntc_thermistor_id[1] },
 214         { .compatible = "murata,ncp21wb473",
 215                 .data = &ntc_thermistor_id[2] },
 216         { .compatible = "murata,ncp03wb473",
 217                 .data = &ntc_thermistor_id[3] },
 218         { .compatible = "murata,ncp15wl333",
 219                 .data = &ntc_thermistor_id[4] },
 220         { .compatible = "epcos,b57330v2103",
 221                 .data = &ntc_thermistor_id[5]},
 222
 223         /* Usage of vendor name "ntc" is deprecated */
 224         { .compatible = "ntc,ncp15wb473",
 225                 .data = &ntc_thermistor_id[0] },
 226         { .compatible = "ntc,ncp18wb473",
 227                 .data = &ntc_thermistor_id[1] },
 228         { .compatible = "ntc,ncp21wb473",
 229                 .data = &ntc_thermistor_id[2] },
 230         { .compatible = "ntc,ncp03wb473",
 231                 .data = &ntc_thermistor_id[3] },
 232         { .compatible = "ntc,ncp15wl333",
 233                 .data = &ntc_thermistor_id[4] },
 234         { },
 235 };
 236 MODULE_DEVICE_TABLE(of, ntc_match);
 237
 238 static struct ntc_thermistor_platform_data *
 239 ntc_thermistor_parse_dt(struct platform_device *pdev)
 240 {
 241         struct iio_channel *chan;
 242         enum iio_chan_type type;
 243         struct device_node *np = pdev->dev.of_node;
 244         struct ntc_thermistor_platform_data *pdata;
 245         int ret;
 246
 247         if (!np)
 248                 return NULL;
 249
 250         pdata = devm_kzalloc(&pdev->dev, sizeof(*pdata), GFP_KERNEL);
 251         if (!pdata)
 252                 return ERR_PTR(-ENOMEM);
 253
 254         chan = iio_channel_get(&pdev->dev, NULL);
 255         if (IS_ERR(chan))
 256                 return ERR_CAST(chan);
 257
 258         ret = iio_get_channel_type(chan, &type);
 259         if (ret < 0)
 260                 return ERR_PTR(ret);
 261
 262         if (type != IIO_VOLTAGE)
 263                 return ERR_PTR(-EINVAL);
 264
 265         if (of_property_read_u32(np, "pullup-uv", &pdata->pullup_uv))
 266                 return ERR_PTR(-ENODEV);
 267         if (of_property_read_u32(np, "pullup-ohm", &pdata->pullup_ohm))
 268                 return ERR_PTR(-ENODEV);
 269         if (of_property_read_u32(np, "pulldown-ohm", &pdata->pulldown_ohm))
 270                 return ERR_PTR(-ENODEV);
 271
 272         if (of_find_property(np, "connected-positive", NULL))
 273                 pdata->connect = NTC_CONNECTED_POSITIVE;
 274         else /* status change should be possible if not always on. */
 275                 pdata->connect = NTC_CONNECTED_GROUND;
 276
 277         pdata->chan = chan;
 278         pdata->read_uv = ntc_adc_iio_read;
 279
 280         return pdata;
 281 }
 282 static void ntc_iio_channel_release(struct ntc_thermistor_platform_data *pdata)
 283 {
 284         if (pdata->chan)
 285                 iio_channel_release(pdata->chan);
 286 }
 287 #else
 288 static struct ntc_thermistor_platform_data *
 289 ntc_thermistor_parse_dt(struct platform_device *pdev)
 290 {
 291         return NULL;
 292 }
 293
 294 #define ntc_match       NULL
 295
 296 static void ntc_iio_channel_release(struct ntc_thermistor_platform_data *pdata)
 297 { }
 298 #endif
 299
 300 static inline u64 div64_u64_safe(u64 dividend, u64 divisor)
 301 {
 302         if (divisor == 0 && dividend == 0)
 303                 return 0;
 304         if (divisor == 0)
 305                 return UINT_MAX;
 306         return div64_u64(dividend, divisor);
 307 }
 308
 309 static int get_ohm_of_thermistor(struct ntc_data *data, unsigned int uv)
 310 {
 311         struct ntc_thermistor_platform_data *pdata = data->pdata;
 312         u64 mv = uv / 1000;
 313         u64 pmv = pdata->pullup_uv / 1000;
 314         u64 n, puo, pdo;
 315         puo = pdata->pullup_ohm;
 316         pdo = pdata->pulldown_ohm;
 317
 318         if (mv == 0) {
 319                 if (pdata->connect == NTC_CONNECTED_POSITIVE)
 320                         return INT_MAX;
 321                 return 0;
 322         }
 323         if (mv >= pmv)
 324                 return (pdata->connect == NTC_CONNECTED_POSITIVE) ?
 325                         0 : INT_MAX;
 326
 327         if (pdata->connect == NTC_CONNECTED_POSITIVE && puo == 0)
 328                 n = div64_u64_safe(pdo * (pmv - mv), mv);
 329         else if (pdata->connect == NTC_CONNECTED_GROUND && pdo == 0)
 330                 n = div64_u64_safe(puo * mv, pmv - mv);
 331         else if (pdata->connect == NTC_CONNECTED_POSITIVE)
 332                 n = div64_u64_safe(pdo * puo * (pmv - mv),
 333                                 puo * mv - pdo * (pmv - mv));
 334         else
 335                 n = div64_u64_safe(pdo * puo * mv, pdo * (pmv - mv) - puo * mv);
 336
 337         if (n > INT_MAX)
 338                 n = INT_MAX;
 339         return n;
 340 }
 341
 342 static void lookup_comp(struct ntc_data *data, unsigned int ohm,
 343                         int *i_low, int *i_high)
 344 {
 345         int start, end, mid;
 346
 347         /*
 348          * Handle special cases: Resistance is higher than or equal to
 349          * resistance in first table entry, or resistance is lower or equal
 350          * to resistance in last table entry.
 351          * In these cases, return i_low == i_high, either pointing to the
 352          * beginning or to the end of the table depending on the condition.
 353          */
 354         if (ohm >= data->comp[0].ohm) {
 355                 *i_low = 0;
 356                 *i_high = 0;
 357                 return;
 358         }
 359         if (ohm <= data->comp[data->n_comp - 1].ohm) {
 360                 *i_low = data->n_comp - 1;
 361                 *i_high = data->n_comp - 1;
 362                 return;
 363         }
 364
 365         /* Do a binary search on compensation table */
 366         start = 0;
 367         end = data->n_comp;
 368         while (start < end) {
 369                 mid = start + (end - start) / 2;
 370                 /*
 371                  * start <= mid < end
 372                  * data->comp[start].ohm > ohm >= data->comp[end].ohm
 373                  *
 374                  * We could check for "ohm == data->comp[mid].ohm" here, but
 375                  * that is a quite unlikely condition, and we would have to
 376                  * check again after updating start. Check it at the end instead
 377                  * for simplicity.
 378                  */
 379                 if (ohm >= data->comp[mid].ohm) {
 380                         end = mid;
 381                 } else {
 382                         start = mid + 1;
 383                         /*
 384                          * ohm >= data->comp[start].ohm might be true here,
 385                          * since we set start to mid + 1. In that case, we are
 386                          * done. We could keep going, but the condition is quite
 387                          * likely to occur, so it is worth checking for it.
 388                          */
 389                         if (ohm >= data->comp[start].ohm)
 390                                 end = start;
 391                 }
 392                 /*
 393                  * start <= end
 394                  * data->comp[start].ohm >= ohm >= data->comp[end].ohm
 395                  */
 396         }
 397         /*
 398          * start == end
 399          * ohm >= data->comp[end].ohm
 400          */
 401         *i_low = end;
 402         if (ohm == data->comp[end].ohm)
 403                 *i_high = end;
 404         else
 405                 *i_high = end - 1;
 406 }
 407
 408 static int get_temp_mc(struct ntc_data *data, unsigned int ohm)
 409 {
 410         int low, high;
 411         int temp;
 412
 413         lookup_comp(data, ohm, &low, &high);
 414         if (low == high) {
 415                 /* Unable to use linear approximation */
 416                 temp = data->comp[low].temp_c * 1000;
 417         } else {
 418                 temp = data->comp[low].temp_c * 1000 +
 419                         ((data->comp[high].temp_c - data->comp[low].temp_c) *
 420                          1000 * ((int)ohm - (int)data->comp[low].ohm)) /
 421                         ((int)data->comp[high].ohm - (int)data->comp[low].ohm);
 422         }
 423         return temp;
 424 }
 425
 426 static int ntc_thermistor_get_ohm(struct ntc_data *data)
 427 {
 428         int read_uv;
 429
 430         if (data->pdata->read_ohm)
 431                 return data->pdata->read_ohm();
 432
 433         if (data->pdata->read_uv) {
 434                 read_uv = data->pdata->read_uv(data->pdata);
 435                 if (read_uv < 0)
 436                         return read_uv;
 437                 return get_ohm_of_thermistor(data, read_uv);
 438         }
 439         return -EINVAL;
 440 }
 441
 442 static int ntc_read_temp(void *dev, long *temp)
 443 {
 444         struct ntc_data *data = dev_get_drvdata(dev);
 445         int ohm;
 446
 447         ohm = ntc_thermistor_get_ohm(data);
 448         if (ohm < 0)
 449                 return ohm;
 450
 451         *temp = get_temp_mc(data, ohm);
 452
 453         return 0;
 454 }
 455
 456 static ssize_t ntc_show_name(struct device *dev,
 457                 struct device_attribute *attr, char *buf)
 458 {
 459         struct ntc_data *data = dev_get_drvdata(dev);
 460
 461         return sprintf(buf, "%s\n", data->name);
 462 }
 463
 464 static ssize_t ntc_show_type(struct device *dev,
 465                 struct device_attribute *attr, char *buf)
 466 {
 467         return sprintf(buf, "4\n");
 468 }
 469
 470 static ssize_t ntc_show_temp(struct device *dev,
 471                 struct device_attribute *attr, char *buf)
 472 {
 473         struct ntc_data *data = dev_get_drvdata(dev);
 474         int ohm;
 475
 476         ohm = ntc_thermistor_get_ohm(data);
 477         if (ohm < 0)
 478                 return ohm;
 479
 480         return sprintf(buf, "%d\n", get_temp_mc(data, ohm));
 481 }
 482
 483 static SENSOR_DEVICE_ATTR(temp1_type, S_IRUGO, ntc_show_type, NULL, 0);
 484 static SENSOR_DEVICE_ATTR(temp1_input, S_IRUGO, ntc_show_temp, NULL, 0);
 485 static DEVICE_ATTR(name, S_IRUGO, ntc_show_name, NULL);
 486
 487 static struct attribute *ntc_attributes[] = {
 488         &dev_attr_name.attr,
 489         &sensor_dev_attr_temp1_type.dev_attr.attr,
 490         &sensor_dev_attr_temp1_input.dev_attr.attr,
 491         NULL,
 492 };
 493
 494 static const struct attribute_group ntc_attr_group = {
 495         .attrs = ntc_attributes,
 496 };
 497
 498 static const struct thermal_zone_of_device_ops ntc_of_thermal_ops = {
 499         .get_temp = ntc_read_temp,
 500 };
 501
 502 static int ntc_thermistor_probe(struct platform_device *pdev)
 503 {
 504         const struct of_device_id *of_id =
 505                         of_match_device(of_match_ptr(ntc_match), &pdev->dev);
 506         const struct platform_device_id *pdev_id;
 507         struct ntc_thermistor_platform_data *pdata;
 508         struct ntc_data *data;
 509         int ret;
 510
 511         pdata = ntc_thermistor_parse_dt(pdev);
 512         if (IS_ERR(pdata))
 513                 return PTR_ERR(pdata);
 514         else if (pdata == NULL)
 515                 pdata = dev_get_platdata(&pdev->dev);
 516
 517         if (!pdata) {
 518                 dev_err(&pdev->dev, "No platform init data supplied.\n");
 519                 return -ENODEV;
 520         }
 521
 522         /* Either one of the two is required. */
 523         if (!pdata->read_uv && !pdata->read_ohm) {
 524                 dev_err(&pdev->dev,
 525                         "Both read_uv and read_ohm missing. Need either one of the two.\n");
 526                 return -EINVAL;
 527         }
 528
 529         if (pdata->read_uv && pdata->read_ohm) {
 530                 dev_warn(&pdev->dev,
 531                          "Only one of read_uv and read_ohm is needed; ignoring read_uv.\n");
 532                 pdata->read_uv = NULL;
 533         }
 534
 535         if (pdata->read_uv && (pdata->pullup_uv == 0 ||
 536                                 (pdata->pullup_ohm == 0 && pdata->connect ==
 537                                  NTC_CONNECTED_GROUND) ||
 538                                 (pdata->pulldown_ohm == 0 && pdata->connect ==
 539                                  NTC_CONNECTED_POSITIVE) ||
 540                                 (pdata->connect != NTC_CONNECTED_POSITIVE &&
 541                                  pdata->connect != NTC_CONNECTED_GROUND))) {
 542                 dev_err(&pdev->dev,
 543                         "Required data to use read_uv not supplied.\n");
 544                 return -EINVAL;
 545         }
 546
 547         data = devm_kzalloc(&pdev->dev, sizeof(struct ntc_data), GFP_KERNEL);
 548         if (!data)
 549                 return -ENOMEM;
 550
 551         pdev_id = of_id ? of_id->data : platform_get_device_id(pdev);
 552
 553         data->dev = &pdev->dev;
 554         data->pdata = pdata;
 555         strlcpy(data->name, pdev_id->name, sizeof(data->name));
 556
 557         switch (pdev_id->driver_data) {
 558         case TYPE_NCPXXWB473:
 559                 data->comp = ncpXXwb473;
 560                 data->n_comp = ARRAY_SIZE(ncpXXwb473);
 561                 break;
 562         case TYPE_NCPXXWL333:
 563                 data->comp = ncpXXwl333;
 564                 data->n_comp = ARRAY_SIZE(ncpXXwl333);
 565                 break;
 566         case TYPE_B57330V2103:
 567                 data->comp = b57330v2103;
 568                 data->n_comp = ARRAY_SIZE(b57330v2103);
 569                 break;
 570         default:
 571                 dev_err(&pdev->dev, "Unknown device type: %lu(%s)\n",
 572                                 pdev_id->driver_data, pdev_id->name);
 573                 return -EINVAL;
 574         }
 575
 576         platform_set_drvdata(pdev, data);
 577
 578         ret = sysfs_create_group(&data->dev->kobj, &ntc_attr_group);
 579         if (ret) {
 580                 dev_err(data->dev, "unable to create sysfs files\n");
 581                 return ret;
 582         }
 583
 584         data->hwmon_dev = hwmon_device_register(data->dev);
 585         if (IS_ERR(data->hwmon_dev)) {
 586                 dev_err(data->dev, "unable to register as hwmon device.\n");
 587                 ret = PTR_ERR(data->hwmon_dev);
 588                 goto err_after_sysfs;
 589         }
 590
 591         dev_info(&pdev->dev, "Thermistor type: %s successfully probed.\n",
 592                                                                 pdev_id->name);
 593
 594         data->tz = thermal_zone_of_sensor_register(data->dev, 0, data->dev,
 595                                                    &ntc_of_thermal_ops);
 596         if (IS_ERR(data->tz)) {
 597                 dev_dbg(&pdev->dev, "Failed to register to thermal fw.\n");
 598                 data->tz = NULL;
 599         }
 600
 601         return 0;
 602 err_after_sysfs:
 603         sysfs_remove_group(&data->dev->kobj, &ntc_attr_group);
 604         ntc_iio_channel_release(pdata);
 605         return ret;
 606 }
 607
 608 static int ntc_thermistor_remove(struct platform_device *pdev)
 609 {
 610         struct ntc_data *data = platform_get_drvdata(pdev);
 611         struct ntc_thermistor_platform_data *pdata = data->pdata;
 612
 613         hwmon_device_unregister(data->hwmon_dev);
 614         sysfs_remove_group(&data->dev->kobj, &ntc_attr_group);
 615         ntc_iio_channel_release(pdata);
 616
 617         thermal_zone_of_sensor_unregister(data->dev, data->tz);
 618
 619         return 0;
 620 }
 621
 622 static struct platform_driver ntc_thermistor_driver = {
 623         .driver = {
 624                 .name = "ntc-thermistor",
 625                 .of_match_table = of_match_ptr(ntc_match),
 626         },
 627         .probe = ntc_thermistor_probe,
 628         .remove = ntc_thermistor_remove,
 629         .id_table = ntc_thermistor_id,
 630 };
 631
 632 module_platform_driver(ntc_thermistor_driver);
 633
 634 MODULE_DESCRIPTION("NTC Thermistor Driver");
 635 MODULE_AUTHOR("MyungJoo Ham <myungjoo.ham@samsung.com>");
 636 MODULE_LICENSE("GPL");
 637 MODULE_ALIAS("platform:ntc-thermistor");