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         { "ncp03wf104", TYPE_NCPXXWF104 },
  57         { },
  58 };
  59
  60 /*
  61  * A compensation table should be sorted by the values of .ohm
  62  * in descending order.
  63  * The following compensation tables are from the specification of Murata NTC
  64  * Thermistors Datasheet
  65  */
  66 static const struct ntc_compensation ncpXXwb473[] = {
  67         { .temp_c       = -40, .ohm     = 1747920 },
  68         { .temp_c       = -35, .ohm     = 1245428 },
  69         { .temp_c       = -30, .ohm     = 898485 },
  70         { .temp_c       = -25, .ohm     = 655802 },
  71         { .temp_c       = -20, .ohm     = 483954 },
  72         { .temp_c       = -15, .ohm     = 360850 },
  73         { .temp_c       = -10, .ohm     = 271697 },
  74         { .temp_c       = -5, .ohm      = 206463 },
  75         { .temp_c       = 0, .ohm       = 158214 },
  76         { .temp_c       = 5, .ohm       = 122259 },
  77         { .temp_c       = 10, .ohm      = 95227 },
  78         { .temp_c       = 15, .ohm      = 74730 },
  79         { .temp_c       = 20, .ohm      = 59065 },
  80         { .temp_c       = 25, .ohm      = 47000 },
  81         { .temp_c       = 30, .ohm      = 37643 },
  82         { .temp_c       = 35, .ohm      = 30334 },
  83         { .temp_c       = 40, .ohm      = 24591 },
  84         { .temp_c       = 45, .ohm      = 20048 },
  85         { .temp_c       = 50, .ohm      = 16433 },
  86         { .temp_c       = 55, .ohm      = 13539 },
  87         { .temp_c       = 60, .ohm      = 11209 },
  88         { .temp_c       = 65, .ohm      = 9328 },
  89         { .temp_c       = 70, .ohm      = 7798 },
  90         { .temp_c       = 75, .ohm      = 6544 },
  91         { .temp_c       = 80, .ohm      = 5518 },
  92         { .temp_c       = 85, .ohm      = 4674 },
  93         { .temp_c       = 90, .ohm      = 3972 },
  94         { .temp_c       = 95, .ohm      = 3388 },
  95         { .temp_c       = 100, .ohm     = 2902 },
  96         { .temp_c       = 105, .ohm     = 2494 },
  97         { .temp_c       = 110, .ohm     = 2150 },
  98         { .temp_c       = 115, .ohm     = 1860 },
  99         { .temp_c       = 120, .ohm     = 1615 },
 100         { .temp_c       = 125, .ohm     = 1406 },
 101 };
 102 static const struct ntc_compensation ncpXXwl333[] = {
 103         { .temp_c       = -40, .ohm     = 1610154 },
 104         { .temp_c       = -35, .ohm     = 1130850 },
 105         { .temp_c       = -30, .ohm     = 802609 },
 106         { .temp_c       = -25, .ohm     = 575385 },
 107         { .temp_c       = -20, .ohm     = 416464 },
 108         { .temp_c       = -15, .ohm     = 304219 },
 109         { .temp_c       = -10, .ohm     = 224193 },
 110         { .temp_c       = -5, .ohm      = 166623 },
 111         { .temp_c       = 0, .ohm       = 124850 },
 112         { .temp_c       = 5, .ohm       = 94287 },
 113         { .temp_c       = 10, .ohm      = 71747 },
 114         { .temp_c       = 15, .ohm      = 54996 },
 115         { .temp_c       = 20, .ohm      = 42455 },
 116         { .temp_c       = 25, .ohm      = 33000 },
 117         { .temp_c       = 30, .ohm      = 25822 },
 118         { .temp_c       = 35, .ohm      = 20335 },
 119         { .temp_c       = 40, .ohm      = 16115 },
 120         { .temp_c       = 45, .ohm      = 12849 },
 121         { .temp_c       = 50, .ohm      = 10306 },
 122         { .temp_c       = 55, .ohm      = 8314 },
 123         { .temp_c       = 60, .ohm      = 6746 },
 124         { .temp_c       = 65, .ohm      = 5503 },
 125         { .temp_c       = 70, .ohm      = 4513 },
 126         { .temp_c       = 75, .ohm      = 3721 },
 127         { .temp_c       = 80, .ohm      = 3084 },
 128         { .temp_c       = 85, .ohm      = 2569 },
 129         { .temp_c       = 90, .ohm      = 2151 },
 130         { .temp_c       = 95, .ohm      = 1809 },
 131         { .temp_c       = 100, .ohm     = 1529 },
 132         { .temp_c       = 105, .ohm     = 1299 },
 133         { .temp_c       = 110, .ohm     = 1108 },
 134         { .temp_c       = 115, .ohm     = 949 },
 135         { .temp_c       = 120, .ohm     = 817 },
 136         { .temp_c       = 125, .ohm     = 707 },
 137 };
 138
 139 static const struct ntc_compensation ncpXXwf104[] = {
 140         { .temp_c       = -40, .ohm     = 4397119 },
 141         { .temp_c       = -35, .ohm     = 3088599 },
 142         { .temp_c       = -30, .ohm     = 2197225 },
 143         { .temp_c       = -25, .ohm     = 1581881 },
 144         { .temp_c       = -20, .ohm     = 1151037 },
 145         { .temp_c       = -15, .ohm     = 846579 },
 146         { .temp_c       = -10, .ohm     = 628988 },
 147         { .temp_c       = -5, .ohm      = 471632 },
 148         { .temp_c       = 0, .ohm       = 357012 },
 149         { .temp_c       = 5, .ohm       = 272500 },
 150         { .temp_c       = 10, .ohm      = 209710 },
 151         { .temp_c       = 15, .ohm      = 162651 },
 152         { .temp_c       = 20, .ohm      = 127080 },
 153         { .temp_c       = 25, .ohm      = 100000 },
 154         { .temp_c       = 30, .ohm      = 79222 },
 155         { .temp_c       = 35, .ohm      = 63167 },
 156         { .temp_c       = 40, .ohm      = 50677 },
 157         { .temp_c       = 45, .ohm      = 40904 },
 158         { .temp_c       = 50, .ohm      = 33195 },
 159         { .temp_c       = 55, .ohm      = 27091 },
 160         { .temp_c       = 60, .ohm      = 22224 },
 161         { .temp_c       = 65, .ohm      = 18323 },
 162         { .temp_c       = 70, .ohm      = 15184 },
 163         { .temp_c       = 75, .ohm      = 12635 },
 164         { .temp_c       = 80, .ohm      = 10566 },
 165         { .temp_c       = 85, .ohm      = 8873 },
 166         { .temp_c       = 90, .ohm      = 7481 },
 167         { .temp_c       = 95, .ohm      = 6337 },
 168         { .temp_c       = 100, .ohm     = 5384 },
 169         { .temp_c       = 105, .ohm     = 4594 },
 170         { .temp_c       = 110, .ohm     = 3934 },
 171         { .temp_c       = 115, .ohm     = 3380 },
 172         { .temp_c       = 120, .ohm     = 2916 },
 173         { .temp_c       = 125, .ohm     = 2522 },
 174 };
 175
 176 /*
 177  * The following compensation table is from the specification of EPCOS NTC
 178  * Thermistors Datasheet
 179  */
 180 static const struct ntc_compensation b57330v2103[] = {
 181         { .temp_c       = -40, .ohm     = 190030 },
 182         { .temp_c       = -35, .ohm     = 145360 },
 183         { .temp_c       = -30, .ohm     = 112060 },
 184         { .temp_c       = -25, .ohm     = 87041 },
 185         { .temp_c       = -20, .ohm     = 68104 },
 186         { .temp_c       = -15, .ohm     = 53665 },
 187         { .temp_c       = -10, .ohm     = 42576 },
 188         { .temp_c       = -5, .ohm      = 34001 },
 189         { .temp_c       = 0, .ohm       = 27326 },
 190         { .temp_c       = 5, .ohm       = 22096 },
 191         { .temp_c       = 10, .ohm      = 17973 },
 192         { .temp_c       = 15, .ohm      = 14703 },
 193         { .temp_c       = 20, .ohm      = 12090 },
 194         { .temp_c       = 25, .ohm      = 10000 },
 195         { .temp_c       = 30, .ohm      = 8311 },
 196         { .temp_c       = 35, .ohm      = 6941 },
 197         { .temp_c       = 40, .ohm      = 5825 },
 198         { .temp_c       = 45, .ohm      = 4911 },
 199         { .temp_c       = 50, .ohm      = 4158 },
 200         { .temp_c       = 55, .ohm      = 3536 },
 201         { .temp_c       = 60, .ohm      = 3019 },
 202         { .temp_c       = 65, .ohm      = 2588 },
 203         { .temp_c       = 70, .ohm      = 2227 },
 204         { .temp_c       = 75, .ohm      = 1924 },
 205         { .temp_c       = 80, .ohm      = 1668 },
 206         { .temp_c       = 85, .ohm      = 1451 },
 207         { .temp_c       = 90, .ohm      = 1266 },
 208         { .temp_c       = 95, .ohm      = 1108 },
 209         { .temp_c       = 100, .ohm     = 973 },
 210         { .temp_c       = 105, .ohm     = 857 },
 211         { .temp_c       = 110, .ohm     = 757 },
 212         { .temp_c       = 115, .ohm     = 671 },
 213         { .temp_c       = 120, .ohm     = 596 },
 214         { .temp_c       = 125, .ohm     = 531 },
 215 };
 216
 217 struct ntc_data {
 218         struct device *hwmon_dev;
 219         struct ntc_thermistor_platform_data *pdata;
 220         const struct ntc_compensation *comp;
 221         struct device *dev;
 222         int n_comp;
 223         char name[PLATFORM_NAME_SIZE];
 224         struct thermal_zone_device *tz;
 225 };
 226
 227 #if defined(CONFIG_OF) && IS_ENABLED(CONFIG_IIO)
 228 static int ntc_adc_iio_read(struct ntc_thermistor_platform_data *pdata)
 229 {
 230         struct iio_channel *channel = pdata->chan;
 231         s64 result;
 232         int val, ret;
 233
 234         ret = iio_read_channel_raw(channel, &val);
 235         if (ret < 0) {
 236                 pr_err("read channel() error: %d\n", ret);
 237                 return ret;
 238         }
 239
 240         /* unit: mV */
 241         result = pdata->pullup_uv * (s64) val;
 242         result >>= 12;
 243
 244         return (int)result;
 245 }
 246
 247 static const struct of_device_id ntc_match[] = {
 248         { .compatible = "murata,ncp15wb473",
 249                 .data = &ntc_thermistor_id[0] },
 250         { .compatible = "murata,ncp18wb473",
 251                 .data = &ntc_thermistor_id[1] },
 252         { .compatible = "murata,ncp21wb473",
 253                 .data = &ntc_thermistor_id[2] },
 254         { .compatible = "murata,ncp03wb473",
 255                 .data = &ntc_thermistor_id[3] },
 256         { .compatible = "murata,ncp15wl333",
 257                 .data = &ntc_thermistor_id[4] },
 258         { .compatible = "epcos,b57330v2103",
 259                 .data = &ntc_thermistor_id[5]},
 260         { .compatible = "murata,ncp03wf104",
 261                 .data = &ntc_thermistor_id[6] },
 262
 263         /* Usage of vendor name "ntc" is deprecated */
 264         { .compatible = "ntc,ncp15wb473",
 265                 .data = &ntc_thermistor_id[0] },
 266         { .compatible = "ntc,ncp18wb473",
 267                 .data = &ntc_thermistor_id[1] },
 268         { .compatible = "ntc,ncp21wb473",
 269                 .data = &ntc_thermistor_id[2] },
 270         { .compatible = "ntc,ncp03wb473",
 271                 .data = &ntc_thermistor_id[3] },
 272         { .compatible = "ntc,ncp15wl333",
 273                 .data = &ntc_thermistor_id[4] },
 274         { },
 275 };
 276 MODULE_DEVICE_TABLE(of, ntc_match);
 277
 278 static struct ntc_thermistor_platform_data *
 279 ntc_thermistor_parse_dt(struct platform_device *pdev)
 280 {
 281         struct iio_channel *chan;
 282         enum iio_chan_type type;
 283         struct device_node *np = pdev->dev.of_node;
 284         struct ntc_thermistor_platform_data *pdata;
 285         int ret;
 286
 287         if (!np)
 288                 return NULL;
 289
 290         pdata = devm_kzalloc(&pdev->dev, sizeof(*pdata), GFP_KERNEL);
 291         if (!pdata)
 292                 return ERR_PTR(-ENOMEM);
 293
 294         chan = iio_channel_get(&pdev->dev, NULL);
 295         if (IS_ERR(chan))
 296                 return ERR_CAST(chan);
 297
 298         ret = iio_get_channel_type(chan, &type);
 299         if (ret < 0)
 300                 return ERR_PTR(ret);
 301
 302         if (type != IIO_VOLTAGE)
 303                 return ERR_PTR(-EINVAL);
 304
 305         if (of_property_read_u32(np, "pullup-uv", &pdata->pullup_uv))
 306                 return ERR_PTR(-ENODEV);
 307         if (of_property_read_u32(np, "pullup-ohm", &pdata->pullup_ohm))
 308                 return ERR_PTR(-ENODEV);
 309         if (of_property_read_u32(np, "pulldown-ohm", &pdata->pulldown_ohm))
 310                 return ERR_PTR(-ENODEV);
 311
 312         if (of_find_property(np, "connected-positive", NULL))
 313                 pdata->connect = NTC_CONNECTED_POSITIVE;
 314         else /* status change should be possible if not always on. */
 315                 pdata->connect = NTC_CONNECTED_GROUND;
 316
 317         pdata->chan = chan;
 318         pdata->read_uv = ntc_adc_iio_read;
 319
 320         return pdata;
 321 }
 322 static void ntc_iio_channel_release(struct ntc_thermistor_platform_data *pdata)
 323 {
 324         if (pdata->chan)
 325                 iio_channel_release(pdata->chan);
 326 }
 327 #else
 328 static struct ntc_thermistor_platform_data *
 329 ntc_thermistor_parse_dt(struct platform_device *pdev)
 330 {
 331         return NULL;
 332 }
 333
 334 #define ntc_match       NULL
 335
 336 static void ntc_iio_channel_release(struct ntc_thermistor_platform_data *pdata)
 337 { }
 338 #endif
 339
 340 static inline u64 div64_u64_safe(u64 dividend, u64 divisor)
 341 {
 342         if (divisor == 0 && dividend == 0)
 343                 return 0;
 344         if (divisor == 0)
 345                 return UINT_MAX;
 346         return div64_u64(dividend, divisor);
 347 }
 348
 349 static int get_ohm_of_thermistor(struct ntc_data *data, unsigned int uv)
 350 {
 351         struct ntc_thermistor_platform_data *pdata = data->pdata;
 352         u64 mv = uv / 1000;
 353         u64 pmv = pdata->pullup_uv / 1000;
 354         u64 n, puo, pdo;
 355         puo = pdata->pullup_ohm;
 356         pdo = pdata->pulldown_ohm;
 357
 358         if (mv == 0) {
 359                 if (pdata->connect == NTC_CONNECTED_POSITIVE)
 360                         return INT_MAX;
 361                 return 0;
 362         }
 363         if (mv >= pmv)
 364                 return (pdata->connect == NTC_CONNECTED_POSITIVE) ?
 365                         0 : INT_MAX;
 366
 367         if (pdata->connect == NTC_CONNECTED_POSITIVE && puo == 0)
 368                 n = div64_u64_safe(pdo * (pmv - mv), mv);
 369         else if (pdata->connect == NTC_CONNECTED_GROUND && pdo == 0)
 370                 n = div64_u64_safe(puo * mv, pmv - mv);
 371         else if (pdata->connect == NTC_CONNECTED_POSITIVE)
 372                 n = div64_u64_safe(pdo * puo * (pmv - mv),
 373                                 puo * mv - pdo * (pmv - mv));
 374         else
 375                 n = div64_u64_safe(pdo * puo * mv, pdo * (pmv - mv) - puo * mv);
 376
 377         if (n > INT_MAX)
 378                 n = INT_MAX;
 379         return n;
 380 }
 381
 382 static void lookup_comp(struct ntc_data *data, unsigned int ohm,
 383                         int *i_low, int *i_high)
 384 {
 385         int start, end, mid;
 386
 387         /*
 388          * Handle special cases: Resistance is higher than or equal to
 389          * resistance in first table entry, or resistance is lower or equal
 390          * to resistance in last table entry.
 391          * In these cases, return i_low == i_high, either pointing to the
 392          * beginning or to the end of the table depending on the condition.
 393          */
 394         if (ohm >= data->comp[0].ohm) {
 395                 *i_low = 0;
 396                 *i_high = 0;
 397                 return;
 398         }
 399         if (ohm <= data->comp[data->n_comp - 1].ohm) {
 400                 *i_low = data->n_comp - 1;
 401                 *i_high = data->n_comp - 1;
 402                 return;
 403         }
 404
 405         /* Do a binary search on compensation table */
 406         start = 0;
 407         end = data->n_comp;
 408         while (start < end) {
 409                 mid = start + (end - start) / 2;
 410                 /*
 411                  * start <= mid < end
 412                  * data->comp[start].ohm > ohm >= data->comp[end].ohm
 413                  *
 414                  * We could check for "ohm == data->comp[mid].ohm" here, but
 415                  * that is a quite unlikely condition, and we would have to
 416                  * check again after updating start. Check it at the end instead
 417                  * for simplicity.
 418                  */
 419                 if (ohm >= data->comp[mid].ohm) {
 420                         end = mid;
 421                 } else {
 422                         start = mid + 1;
 423                         /*
 424                          * ohm >= data->comp[start].ohm might be true here,
 425                          * since we set start to mid + 1. In that case, we are
 426                          * done. We could keep going, but the condition is quite
 427                          * likely to occur, so it is worth checking for it.
 428                          */
 429                         if (ohm >= data->comp[start].ohm)
 430                                 end = start;
 431                 }
 432                 /*
 433                  * start <= end
 434                  * data->comp[start].ohm >= ohm >= data->comp[end].ohm
 435                  */
 436         }
 437         /*
 438          * start == end
 439          * ohm >= data->comp[end].ohm
 440          */
 441         *i_low = end;
 442         if (ohm == data->comp[end].ohm)
 443                 *i_high = end;
 444         else
 445                 *i_high = end - 1;
 446 }
 447
 448 static int get_temp_mc(struct ntc_data *data, unsigned int ohm)
 449 {
 450         int low, high;
 451         int temp;
 452
 453         lookup_comp(data, ohm, &low, &high);
 454         if (low == high) {
 455                 /* Unable to use linear approximation */
 456                 temp = data->comp[low].temp_c * 1000;
 457         } else {
 458                 temp = data->comp[low].temp_c * 1000 +
 459                         ((data->comp[high].temp_c - data->comp[low].temp_c) *
 460                          1000 * ((int)ohm - (int)data->comp[low].ohm)) /
 461                         ((int)data->comp[high].ohm - (int)data->comp[low].ohm);
 462         }
 463         return temp;
 464 }
 465
 466 static int ntc_thermistor_get_ohm(struct ntc_data *data)
 467 {
 468         int read_uv;
 469
 470         if (data->pdata->read_ohm)
 471                 return data->pdata->read_ohm();
 472
 473         if (data->pdata->read_uv) {
 474                 read_uv = data->pdata->read_uv(data->pdata);
 475                 if (read_uv < 0)
 476                         return read_uv;
 477                 return get_ohm_of_thermistor(data, read_uv);
 478         }
 479         return -EINVAL;
 480 }
 481
 482 static int ntc_read_temp(void *dev, long *temp)
 483 {
 484         struct ntc_data *data = dev_get_drvdata(dev);
 485         int ohm;
 486
 487         ohm = ntc_thermistor_get_ohm(data);
 488         if (ohm < 0)
 489                 return ohm;
 490
 491         *temp = get_temp_mc(data, ohm);
 492
 493         return 0;
 494 }
 495
 496 static ssize_t ntc_show_name(struct device *dev,
 497                 struct device_attribute *attr, char *buf)
 498 {
 499         struct ntc_data *data = dev_get_drvdata(dev);
 500
 501         return sprintf(buf, "%s\n", data->name);
 502 }
 503
 504 static ssize_t ntc_show_type(struct device *dev,
 505                 struct device_attribute *attr, char *buf)
 506 {
 507         return sprintf(buf, "4\n");
 508 }
 509
 510 static ssize_t ntc_show_temp(struct device *dev,
 511                 struct device_attribute *attr, char *buf)
 512 {
 513         struct ntc_data *data = dev_get_drvdata(dev);
 514         int ohm;
 515
 516         ohm = ntc_thermistor_get_ohm(data);
 517         if (ohm < 0)
 518                 return ohm;
 519
 520         return sprintf(buf, "%d\n", get_temp_mc(data, ohm));
 521 }
 522
 523 static SENSOR_DEVICE_ATTR(temp1_type, S_IRUGO, ntc_show_type, NULL, 0);
 524 static SENSOR_DEVICE_ATTR(temp1_input, S_IRUGO, ntc_show_temp, NULL, 0);
 525 static DEVICE_ATTR(name, S_IRUGO, ntc_show_name, NULL);
 526
 527 static struct attribute *ntc_attributes[] = {
 528         &dev_attr_name.attr,
 529         &sensor_dev_attr_temp1_type.dev_attr.attr,
 530         &sensor_dev_attr_temp1_input.dev_attr.attr,
 531         NULL,
 532 };
 533
 534 static const struct attribute_group ntc_attr_group = {
 535         .attrs = ntc_attributes,
 536 };
 537
 538 static const struct thermal_zone_of_device_ops ntc_of_thermal_ops = {
 539         .get_temp = ntc_read_temp,
 540 };
 541
 542 static int ntc_thermistor_probe(struct platform_device *pdev)
 543 {
 544         const struct of_device_id *of_id =
 545                         of_match_device(of_match_ptr(ntc_match), &pdev->dev);
 546         const struct platform_device_id *pdev_id;
 547         struct ntc_thermistor_platform_data *pdata;
 548         struct ntc_data *data;
 549         int ret;
 550
 551         pdata = ntc_thermistor_parse_dt(pdev);
 552         if (IS_ERR(pdata))
 553                 return PTR_ERR(pdata);
 554         else if (pdata == NULL)
 555                 pdata = dev_get_platdata(&pdev->dev);
 556
 557         if (!pdata) {
 558                 dev_err(&pdev->dev, "No platform init data supplied.\n");
 559                 return -ENODEV;
 560         }
 561
 562         /* Either one of the two is required. */
 563         if (!pdata->read_uv && !pdata->read_ohm) {
 564                 dev_err(&pdev->dev,
 565                         "Both read_uv and read_ohm missing. Need either one of the two.\n");
 566                 return -EINVAL;
 567         }
 568
 569         if (pdata->read_uv && pdata->read_ohm) {
 570                 dev_warn(&pdev->dev,
 571                          "Only one of read_uv and read_ohm is needed; ignoring read_uv.\n");
 572                 pdata->read_uv = NULL;
 573         }
 574
 575         if (pdata->read_uv && (pdata->pullup_uv == 0 ||
 576                                 (pdata->pullup_ohm == 0 && pdata->connect ==
 577                                  NTC_CONNECTED_GROUND) ||
 578                                 (pdata->pulldown_ohm == 0 && pdata->connect ==
 579                                  NTC_CONNECTED_POSITIVE) ||
 580                                 (pdata->connect != NTC_CONNECTED_POSITIVE &&
 581                                  pdata->connect != NTC_CONNECTED_GROUND))) {
 582                 dev_err(&pdev->dev,
 583                         "Required data to use read_uv not supplied.\n");
 584                 return -EINVAL;
 585         }
 586
 587         data = devm_kzalloc(&pdev->dev, sizeof(struct ntc_data), GFP_KERNEL);
 588         if (!data)
 589                 return -ENOMEM;
 590
 591         pdev_id = of_id ? of_id->data : platform_get_device_id(pdev);
 592
 593         data->dev = &pdev->dev;
 594         data->pdata = pdata;
 595         strlcpy(data->name, pdev_id->name, sizeof(data->name));
 596
 597         switch (pdev_id->driver_data) {
 598         case TYPE_NCPXXWB473:
 599                 data->comp = ncpXXwb473;
 600                 data->n_comp = ARRAY_SIZE(ncpXXwb473);
 601                 break;
 602         case TYPE_NCPXXWL333:
 603                 data->comp = ncpXXwl333;
 604                 data->n_comp = ARRAY_SIZE(ncpXXwl333);
 605                 break;
 606         case TYPE_B57330V2103:
 607                 data->comp = b57330v2103;
 608                 data->n_comp = ARRAY_SIZE(b57330v2103);
 609                 break;
 610         case TYPE_NCPXXWF104:
 611                 data->comp = ncpXXwf104;
 612                 data->n_comp = ARRAY_SIZE(ncpXXwf104);
 613                 break;
 614         default:
 615                 dev_err(&pdev->dev, "Unknown device type: %lu(%s)\n",
 616                                 pdev_id->driver_data, pdev_id->name);
 617                 return -EINVAL;
 618         }
 619
 620         platform_set_drvdata(pdev, data);
 621
 622         ret = sysfs_create_group(&data->dev->kobj, &ntc_attr_group);
 623         if (ret) {
 624                 dev_err(data->dev, "unable to create sysfs files\n");
 625                 return ret;
 626         }
 627
 628         data->hwmon_dev = hwmon_device_register(data->dev);
 629         if (IS_ERR(data->hwmon_dev)) {
 630                 dev_err(data->dev, "unable to register as hwmon device.\n");
 631                 ret = PTR_ERR(data->hwmon_dev);
 632                 goto err_after_sysfs;
 633         }
 634
 635         dev_info(&pdev->dev, "Thermistor type: %s successfully probed.\n",
 636                                                                 pdev_id->name);
 637
 638         data->tz = thermal_zone_of_sensor_register(data->dev, 0, data->dev,
 639                                                    &ntc_of_thermal_ops);
 640         if (IS_ERR(data->tz)) {
 641                 dev_dbg(&pdev->dev, "Failed to register to thermal fw.\n");
 642                 data->tz = NULL;
 643         }
 644
 645         return 0;
 646 err_after_sysfs:
 647         sysfs_remove_group(&data->dev->kobj, &ntc_attr_group);
 648         ntc_iio_channel_release(pdata);
 649         return ret;
 650 }
 651
 652 static int ntc_thermistor_remove(struct platform_device *pdev)
 653 {
 654         struct ntc_data *data = platform_get_drvdata(pdev);
 655         struct ntc_thermistor_platform_data *pdata = data->pdata;
 656
 657         hwmon_device_unregister(data->hwmon_dev);
 658         sysfs_remove_group(&data->dev->kobj, &ntc_attr_group);
 659         ntc_iio_channel_release(pdata);
 660
 661         thermal_zone_of_sensor_unregister(data->dev, data->tz);
 662
 663         return 0;
 664 }
 665
 666 static struct platform_driver ntc_thermistor_driver = {
 667         .driver = {
 668                 .name = "ntc-thermistor",
 669                 .of_match_table = of_match_ptr(ntc_match),
 670         },
 671         .probe = ntc_thermistor_probe,
 672         .remove = ntc_thermistor_remove,
 673         .id_table = ntc_thermistor_id,
 674 };
 675
 676 module_platform_driver(ntc_thermistor_driver);
 677
 678 MODULE_DESCRIPTION("NTC Thermistor Driver");
 679 MODULE_AUTHOR("MyungJoo Ham <myungjoo.ham@samsung.com>");
 680 MODULE_LICENSE("GPL");
 681 MODULE_ALIAS("platform:ntc-thermistor");