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         int raw, uv, ret;
 232
 233         ret = iio_read_channel_raw(channel, &raw);
 234         if (ret < 0) {
 235                 pr_err("read channel() error: %d\n", ret);
 236                 return ret;
 237         }
 238
 239         ret = iio_convert_raw_to_processed(channel, raw, &uv, 1000);
 240         if (ret < 0) {
 241                 /* Assume 12 bit ADC with vref at pullup_uv */
 242                 uv = (pdata->pullup_uv * (s64)raw) >> 12;
 243         }
 244
 245         return uv;
 246 }
 247
 248 static const struct of_device_id ntc_match[] = {
 249         { .compatible = "murata,ncp15wb473",
 250                 .data = &ntc_thermistor_id[0] },
 251         { .compatible = "murata,ncp18wb473",
 252                 .data = &ntc_thermistor_id[1] },
 253         { .compatible = "murata,ncp21wb473",
 254                 .data = &ntc_thermistor_id[2] },
 255         { .compatible = "murata,ncp03wb473",
 256                 .data = &ntc_thermistor_id[3] },
 257         { .compatible = "murata,ncp15wl333",
 258                 .data = &ntc_thermistor_id[4] },
 259         { .compatible = "epcos,b57330v2103",
 260                 .data = &ntc_thermistor_id[5]},
 261         { .compatible = "murata,ncp03wf104",
 262                 .data = &ntc_thermistor_id[6] },
 263
 264         /* Usage of vendor name "ntc" is deprecated */
 265         { .compatible = "ntc,ncp15wb473",
 266                 .data = &ntc_thermistor_id[0] },
 267         { .compatible = "ntc,ncp18wb473",
 268                 .data = &ntc_thermistor_id[1] },
 269         { .compatible = "ntc,ncp21wb473",
 270                 .data = &ntc_thermistor_id[2] },
 271         { .compatible = "ntc,ncp03wb473",
 272                 .data = &ntc_thermistor_id[3] },
 273         { .compatible = "ntc,ncp15wl333",
 274                 .data = &ntc_thermistor_id[4] },
 275         { },
 276 };
 277 MODULE_DEVICE_TABLE(of, ntc_match);
 278
 279 static struct ntc_thermistor_platform_data *
 280 ntc_thermistor_parse_dt(struct platform_device *pdev)
 281 {
 282         struct iio_channel *chan;
 283         enum iio_chan_type type;
 284         struct device_node *np = pdev->dev.of_node;
 285         struct ntc_thermistor_platform_data *pdata;
 286         int ret;
 287
 288         if (!np)
 289                 return NULL;
 290
 291         pdata = devm_kzalloc(&pdev->dev, sizeof(*pdata), GFP_KERNEL);
 292         if (!pdata)
 293                 return ERR_PTR(-ENOMEM);
 294
 295         chan = iio_channel_get(&pdev->dev, NULL);
 296         if (IS_ERR(chan))
 297                 return ERR_CAST(chan);
 298
 299         ret = iio_get_channel_type(chan, &type);
 300         if (ret < 0)
 301                 return ERR_PTR(ret);
 302
 303         if (type != IIO_VOLTAGE)
 304                 return ERR_PTR(-EINVAL);
 305
 306         if (of_property_read_u32(np, "pullup-uv", &pdata->pullup_uv))
 307                 return ERR_PTR(-ENODEV);
 308         if (of_property_read_u32(np, "pullup-ohm", &pdata->pullup_ohm))
 309                 return ERR_PTR(-ENODEV);
 310         if (of_property_read_u32(np, "pulldown-ohm", &pdata->pulldown_ohm))
 311                 return ERR_PTR(-ENODEV);
 312
 313         if (of_find_property(np, "connected-positive", NULL))
 314                 pdata->connect = NTC_CONNECTED_POSITIVE;
 315         else /* status change should be possible if not always on. */
 316                 pdata->connect = NTC_CONNECTED_GROUND;
 317
 318         pdata->chan = chan;
 319         pdata->read_uv = ntc_adc_iio_read;
 320
 321         return pdata;
 322 }
 323 static void ntc_iio_channel_release(struct ntc_thermistor_platform_data *pdata)
 324 {
 325         if (pdata->chan)
 326                 iio_channel_release(pdata->chan);
 327 }
 328 #else
 329 static struct ntc_thermistor_platform_data *
 330 ntc_thermistor_parse_dt(struct platform_device *pdev)
 331 {
 332         return NULL;
 333 }
 334
 335 #define ntc_match       NULL
 336
 337 static void ntc_iio_channel_release(struct ntc_thermistor_platform_data *pdata)
 338 { }
 339 #endif
 340
 341 static inline u64 div64_u64_safe(u64 dividend, u64 divisor)
 342 {
 343         if (divisor == 0 && dividend == 0)
 344                 return 0;
 345         if (divisor == 0)
 346                 return UINT_MAX;
 347         return div64_u64(dividend, divisor);
 348 }
 349
 350 static int get_ohm_of_thermistor(struct ntc_data *data, unsigned int uv)
 351 {
 352         struct ntc_thermistor_platform_data *pdata = data->pdata;
 353         u32 puv = pdata->pullup_uv;
 354         u64 n, puo, pdo;
 355         puo = pdata->pullup_ohm;
 356         pdo = pdata->pulldown_ohm;
 357
 358         if (uv == 0)
 359                 return (pdata->connect == NTC_CONNECTED_POSITIVE) ?
 360                         INT_MAX : 0;
 361         if (uv >= puv)
 362                 return (pdata->connect == NTC_CONNECTED_POSITIVE) ?
 363                         0 : INT_MAX;
 364
 365         if (pdata->connect == NTC_CONNECTED_POSITIVE && puo == 0)
 366                 n = div_u64(pdo * (puv - uv), uv);
 367         else if (pdata->connect == NTC_CONNECTED_GROUND && pdo == 0)
 368                 n = div_u64(puo * uv, puv - uv);
 369         else if (pdata->connect == NTC_CONNECTED_POSITIVE)
 370                 n = div64_u64_safe(pdo * puo * (puv - uv),
 371                                 puo * uv - pdo * (puv - uv));
 372         else
 373                 n = div64_u64_safe(pdo * puo * uv, pdo * (puv - uv) - puo * uv);
 374
 375         if (n > INT_MAX)
 376                 n = INT_MAX;
 377         return n;
 378 }
 379
 380 static void lookup_comp(struct ntc_data *data, unsigned int ohm,
 381                         int *i_low, int *i_high)
 382 {
 383         int start, end, mid;
 384
 385         /*
 386          * Handle special cases: Resistance is higher than or equal to
 387          * resistance in first table entry, or resistance is lower or equal
 388          * to resistance in last table entry.
 389          * In these cases, return i_low == i_high, either pointing to the
 390          * beginning or to the end of the table depending on the condition.
 391          */
 392         if (ohm >= data->comp[0].ohm) {
 393                 *i_low = 0;
 394                 *i_high = 0;
 395                 return;
 396         }
 397         if (ohm <= data->comp[data->n_comp - 1].ohm) {
 398                 *i_low = data->n_comp - 1;
 399                 *i_high = data->n_comp - 1;
 400                 return;
 401         }
 402
 403         /* Do a binary search on compensation table */
 404         start = 0;
 405         end = data->n_comp;
 406         while (start < end) {
 407                 mid = start + (end - start) / 2;
 408                 /*
 409                  * start <= mid < end
 410                  * data->comp[start].ohm > ohm >= data->comp[end].ohm
 411                  *
 412                  * We could check for "ohm == data->comp[mid].ohm" here, but
 413                  * that is a quite unlikely condition, and we would have to
 414                  * check again after updating start. Check it at the end instead
 415                  * for simplicity.
 416                  */
 417                 if (ohm >= data->comp[mid].ohm) {
 418                         end = mid;
 419                 } else {
 420                         start = mid + 1;
 421                         /*
 422                          * ohm >= data->comp[start].ohm might be true here,
 423                          * since we set start to mid + 1. In that case, we are
 424                          * done. We could keep going, but the condition is quite
 425                          * likely to occur, so it is worth checking for it.
 426                          */
 427                         if (ohm >= data->comp[start].ohm)
 428                                 end = start;
 429                 }
 430                 /*
 431                  * start <= end
 432                  * data->comp[start].ohm >= ohm >= data->comp[end].ohm
 433                  */
 434         }
 435         /*
 436          * start == end
 437          * ohm >= data->comp[end].ohm
 438          */
 439         *i_low = end;
 440         if (ohm == data->comp[end].ohm)
 441                 *i_high = end;
 442         else
 443                 *i_high = end - 1;
 444 }
 445
 446 static int get_temp_mc(struct ntc_data *data, unsigned int ohm)
 447 {
 448         int low, high;
 449         int temp;
 450
 451         lookup_comp(data, ohm, &low, &high);
 452         if (low == high) {
 453                 /* Unable to use linear approximation */
 454                 temp = data->comp[low].temp_c * 1000;
 455         } else {
 456                 temp = data->comp[low].temp_c * 1000 +
 457                         ((data->comp[high].temp_c - data->comp[low].temp_c) *
 458                          1000 * ((int)ohm - (int)data->comp[low].ohm)) /
 459                         ((int)data->comp[high].ohm - (int)data->comp[low].ohm);
 460         }
 461         return temp;
 462 }
 463
 464 static int ntc_thermistor_get_ohm(struct ntc_data *data)
 465 {
 466         int read_uv;
 467
 468         if (data->pdata->read_ohm)
 469                 return data->pdata->read_ohm();
 470
 471         if (data->pdata->read_uv) {
 472                 read_uv = data->pdata->read_uv(data->pdata);
 473                 if (read_uv < 0)
 474                         return read_uv;
 475                 return get_ohm_of_thermistor(data, read_uv);
 476         }
 477         return -EINVAL;
 478 }
 479
 480 static int ntc_read_temp(void *dev, long *temp)
 481 {
 482         struct ntc_data *data = dev_get_drvdata(dev);
 483         int ohm;
 484
 485         ohm = ntc_thermistor_get_ohm(data);
 486         if (ohm < 0)
 487                 return ohm;
 488
 489         *temp = get_temp_mc(data, ohm);
 490
 491         return 0;
 492 }
 493
 494 static ssize_t ntc_show_name(struct device *dev,
 495                 struct device_attribute *attr, char *buf)
 496 {
 497         struct ntc_data *data = dev_get_drvdata(dev);
 498
 499         return sprintf(buf, "%s\n", data->name);
 500 }
 501
 502 static ssize_t ntc_show_type(struct device *dev,
 503                 struct device_attribute *attr, char *buf)
 504 {
 505         return sprintf(buf, "4\n");
 506 }
 507
 508 static ssize_t ntc_show_temp(struct device *dev,
 509                 struct device_attribute *attr, char *buf)
 510 {
 511         struct ntc_data *data = dev_get_drvdata(dev);
 512         int ohm;
 513
 514         ohm = ntc_thermistor_get_ohm(data);
 515         if (ohm < 0)
 516                 return ohm;
 517
 518         return sprintf(buf, "%d\n", get_temp_mc(data, ohm));
 519 }
 520
 521 static SENSOR_DEVICE_ATTR(temp1_type, S_IRUGO, ntc_show_type, NULL, 0);
 522 static SENSOR_DEVICE_ATTR(temp1_input, S_IRUGO, ntc_show_temp, NULL, 0);
 523 static DEVICE_ATTR(name, S_IRUGO, ntc_show_name, NULL);
 524
 525 static struct attribute *ntc_attributes[] = {
 526         &dev_attr_name.attr,
 527         &sensor_dev_attr_temp1_type.dev_attr.attr,
 528         &sensor_dev_attr_temp1_input.dev_attr.attr,
 529         NULL,
 530 };
 531
 532 static const struct attribute_group ntc_attr_group = {
 533         .attrs = ntc_attributes,
 534 };
 535
 536 static const struct thermal_zone_of_device_ops ntc_of_thermal_ops = {
 537         .get_temp = ntc_read_temp,
 538 };
 539
 540 static int ntc_thermistor_probe(struct platform_device *pdev)
 541 {
 542         const struct of_device_id *of_id =
 543                         of_match_device(of_match_ptr(ntc_match), &pdev->dev);
 544         const struct platform_device_id *pdev_id;
 545         struct ntc_thermistor_platform_data *pdata;
 546         struct ntc_data *data;
 547         int ret;
 548
 549         pdata = ntc_thermistor_parse_dt(pdev);
 550         if (IS_ERR(pdata))
 551                 return PTR_ERR(pdata);
 552         else if (pdata == NULL)
 553                 pdata = dev_get_platdata(&pdev->dev);
 554
 555         if (!pdata) {
 556                 dev_err(&pdev->dev, "No platform init data supplied.\n");
 557                 return -ENODEV;
 558         }
 559
 560         /* Either one of the two is required. */
 561         if (!pdata->read_uv && !pdata->read_ohm) {
 562                 dev_err(&pdev->dev,
 563                         "Both read_uv and read_ohm missing. Need either one of the two.\n");
 564                 return -EINVAL;
 565         }
 566
 567         if (pdata->read_uv && pdata->read_ohm) {
 568                 dev_warn(&pdev->dev,
 569                          "Only one of read_uv and read_ohm is needed; ignoring read_uv.\n");
 570                 pdata->read_uv = NULL;
 571         }
 572
 573         if (pdata->read_uv && (pdata->pullup_uv == 0 ||
 574                                 (pdata->pullup_ohm == 0 && pdata->connect ==
 575                                  NTC_CONNECTED_GROUND) ||
 576                                 (pdata->pulldown_ohm == 0 && pdata->connect ==
 577                                  NTC_CONNECTED_POSITIVE) ||
 578                                 (pdata->connect != NTC_CONNECTED_POSITIVE &&
 579                                  pdata->connect != NTC_CONNECTED_GROUND))) {
 580                 dev_err(&pdev->dev,
 581                         "Required data to use read_uv not supplied.\n");
 582                 return -EINVAL;
 583         }
 584
 585         data = devm_kzalloc(&pdev->dev, sizeof(struct ntc_data), GFP_KERNEL);
 586         if (!data)
 587                 return -ENOMEM;
 588
 589         pdev_id = of_id ? of_id->data : platform_get_device_id(pdev);
 590
 591         data->dev = &pdev->dev;
 592         data->pdata = pdata;
 593         strlcpy(data->name, pdev_id->name, sizeof(data->name));
 594
 595         switch (pdev_id->driver_data) {
 596         case TYPE_NCPXXWB473:
 597                 data->comp = ncpXXwb473;
 598                 data->n_comp = ARRAY_SIZE(ncpXXwb473);
 599                 break;
 600         case TYPE_NCPXXWL333:
 601                 data->comp = ncpXXwl333;
 602                 data->n_comp = ARRAY_SIZE(ncpXXwl333);
 603                 break;
 604         case TYPE_B57330V2103:
 605                 data->comp = b57330v2103;
 606                 data->n_comp = ARRAY_SIZE(b57330v2103);
 607                 break;
 608         case TYPE_NCPXXWF104:
 609                 data->comp = ncpXXwf104;
 610                 data->n_comp = ARRAY_SIZE(ncpXXwf104);
 611                 break;
 612         default:
 613                 dev_err(&pdev->dev, "Unknown device type: %lu(%s)\n",
 614                                 pdev_id->driver_data, pdev_id->name);
 615                 return -EINVAL;
 616         }
 617
 618         platform_set_drvdata(pdev, data);
 619
 620         ret = sysfs_create_group(&data->dev->kobj, &ntc_attr_group);
 621         if (ret) {
 622                 dev_err(data->dev, "unable to create sysfs files\n");
 623                 return ret;
 624         }
 625
 626         data->hwmon_dev = hwmon_device_register(data->dev);
 627         if (IS_ERR(data->hwmon_dev)) {
 628                 dev_err(data->dev, "unable to register as hwmon device.\n");
 629                 ret = PTR_ERR(data->hwmon_dev);
 630                 goto err_after_sysfs;
 631         }
 632
 633         dev_info(&pdev->dev, "Thermistor type: %s successfully probed.\n",
 634                                                                 pdev_id->name);
 635
 636         data->tz = thermal_zone_of_sensor_register(data->dev, 0, data->dev,
 637                                                    &ntc_of_thermal_ops);
 638         if (IS_ERR(data->tz)) {
 639                 dev_dbg(&pdev->dev, "Failed to register to thermal fw.\n");
 640                 data->tz = NULL;
 641         }
 642
 643         return 0;
 644 err_after_sysfs:
 645         sysfs_remove_group(&data->dev->kobj, &ntc_attr_group);
 646         ntc_iio_channel_release(pdata);
 647         return ret;
 648 }
 649
 650 static int ntc_thermistor_remove(struct platform_device *pdev)
 651 {
 652         struct ntc_data *data = platform_get_drvdata(pdev);
 653         struct ntc_thermistor_platform_data *pdata = data->pdata;
 654
 655         hwmon_device_unregister(data->hwmon_dev);
 656         sysfs_remove_group(&data->dev->kobj, &ntc_attr_group);
 657         ntc_iio_channel_release(pdata);
 658
 659         thermal_zone_of_sensor_unregister(data->dev, data->tz);
 660
 661         return 0;
 662 }
 663
 664 static struct platform_driver ntc_thermistor_driver = {
 665         .driver = {
 666                 .name = "ntc-thermistor",
 667                 .of_match_table = of_match_ptr(ntc_match),
 668         },
 669         .probe = ntc_thermistor_probe,
 670         .remove = ntc_thermistor_remove,
 671         .id_table = ntc_thermistor_id,
 672 };
 673
 674 module_platform_driver(ntc_thermistor_driver);
 675
 676 MODULE_DESCRIPTION("NTC Thermistor Driver");
 677 MODULE_AUTHOR("MyungJoo Ham <myungjoo.ham@samsung.com>");
 678 MODULE_LICENSE("GPL");
 679 MODULE_ALIAS("platform:ntc-thermistor");