drivers/hwmon/ntc_thermistor.c

   1 // SPDX-License-Identifier: GPL-2.0-or-later
   2 /*
   3  * ntc_thermistor.c - NTC Thermistors
   4  *
   5  *  Copyright (C) 2010 Samsung Electronics
   6  *  MyungJoo Ham <myungjoo.ham@samsung.com>
   7  */
   8
   9 #include <linux/slab.h>
  10 #include <linux/module.h>
  11 #include <linux/math64.h>
  12 #include <linux/mod_devicetable.h>
  13 #include <linux/platform_device.h>
  14 #include <linux/property.h>
  15 #include <linux/err.h>
  16 #include <linux/fixp-arith.h>
  17 #include <linux/iio/consumer.h>
  18 #include <linux/hwmon.h>
  19
  20 enum ntc_thermistor_type {
  21         TYPE_B57330V2103,
  22         TYPE_B57891S0103,
  23         TYPE_NCPXXWB473,
  24         TYPE_NCPXXWF104,
  25         TYPE_NCPXXWL333,
  26         TYPE_NCPXXXH103,
  27 };
  28
  29 struct ntc_compensation {
  30         int             temp_c;
  31         unsigned int    ohm;
  32 };
  33
  34 /*
  35  * Used as index in a zero-terminated array, holes not allowed so
  36  * that NTC_LAST is the first empty array entry.
  37  */
  38 enum {
  39         NTC_B57330V2103,
  40         NTC_B57891S0103,
  41         NTC_NCP03WB473,
  42         NTC_NCP03WF104,
  43         NTC_NCP15WB473,
  44         NTC_NCP15WL333,
  45         NTC_NCP15XH103,
  46         NTC_NCP18WB473,
  47         NTC_NCP21WB473,
  48         NTC_SSG1404001221,
  49         NTC_LAST,
  50 };
  51
  52 static const struct platform_device_id ntc_thermistor_id[] = {
  53         [NTC_B57330V2103]     = { "b57330v2103",     TYPE_B57330V2103 },
  54         [NTC_B57891S0103]     = { "b57891s0103",     TYPE_B57891S0103 },
  55         [NTC_NCP03WB473]      = { "ncp03wb473",      TYPE_NCPXXWB473 },
  56         [NTC_NCP03WF104]      = { "ncp03wf104",      TYPE_NCPXXWF104 },
  57         [NTC_NCP15WB473]      = { "ncp15wb473",      TYPE_NCPXXWB473 },
  58         [NTC_NCP15WL333]      = { "ncp15wl333",      TYPE_NCPXXWL333 },
  59         [NTC_NCP15XH103]      = { "ncp15xh103",      TYPE_NCPXXXH103 },
  60         [NTC_NCP18WB473]      = { "ncp18wb473",      TYPE_NCPXXWB473 },
  61         [NTC_NCP21WB473]      = { "ncp21wb473",      TYPE_NCPXXWB473 },
  62         [NTC_SSG1404001221]   = { "ssg1404_001221",  TYPE_NCPXXWB473 },
  63         [NTC_LAST]            = { },
  64 };
  65 MODULE_DEVICE_TABLE(platform, ntc_thermistor_id);
  66
  67 /*
  68  * A compensation table should be sorted by the values of .ohm
  69  * in descending order.
  70  * The following compensation tables are from the specification of Murata NTC
  71  * Thermistors Datasheet
  72  */
  73 static const struct ntc_compensation ncpXXwb473[] = {
  74         { .temp_c       = -40, .ohm     = 1747920 },
  75         { .temp_c       = -35, .ohm     = 1245428 },
  76         { .temp_c       = -30, .ohm     = 898485 },
  77         { .temp_c       = -25, .ohm     = 655802 },
  78         { .temp_c       = -20, .ohm     = 483954 },
  79         { .temp_c       = -15, .ohm     = 360850 },
  80         { .temp_c       = -10, .ohm     = 271697 },
  81         { .temp_c       = -5, .ohm      = 206463 },
  82         { .temp_c       = 0, .ohm       = 158214 },
  83         { .temp_c       = 5, .ohm       = 122259 },
  84         { .temp_c       = 10, .ohm      = 95227 },
  85         { .temp_c       = 15, .ohm      = 74730 },
  86         { .temp_c       = 20, .ohm      = 59065 },
  87         { .temp_c       = 25, .ohm      = 47000 },
  88         { .temp_c       = 30, .ohm      = 37643 },
  89         { .temp_c       = 35, .ohm      = 30334 },
  90         { .temp_c       = 40, .ohm      = 24591 },
  91         { .temp_c       = 45, .ohm      = 20048 },
  92         { .temp_c       = 50, .ohm      = 16433 },
  93         { .temp_c       = 55, .ohm      = 13539 },
  94         { .temp_c       = 60, .ohm      = 11209 },
  95         { .temp_c       = 65, .ohm      = 9328 },
  96         { .temp_c       = 70, .ohm      = 7798 },
  97         { .temp_c       = 75, .ohm      = 6544 },
  98         { .temp_c       = 80, .ohm      = 5518 },
  99         { .temp_c       = 85, .ohm      = 4674 },
 100         { .temp_c       = 90, .ohm      = 3972 },
 101         { .temp_c       = 95, .ohm      = 3388 },
 102         { .temp_c       = 100, .ohm     = 2902 },
 103         { .temp_c       = 105, .ohm     = 2494 },
 104         { .temp_c       = 110, .ohm     = 2150 },
 105         { .temp_c       = 115, .ohm     = 1860 },
 106         { .temp_c       = 120, .ohm     = 1615 },
 107         { .temp_c       = 125, .ohm     = 1406 },
 108 };
 109 static const struct ntc_compensation ncpXXwl333[] = {
 110         { .temp_c       = -40, .ohm     = 1610154 },
 111         { .temp_c       = -35, .ohm     = 1130850 },
 112         { .temp_c       = -30, .ohm     = 802609 },
 113         { .temp_c       = -25, .ohm     = 575385 },
 114         { .temp_c       = -20, .ohm     = 416464 },
 115         { .temp_c       = -15, .ohm     = 304219 },
 116         { .temp_c       = -10, .ohm     = 224193 },
 117         { .temp_c       = -5, .ohm      = 166623 },
 118         { .temp_c       = 0, .ohm       = 124850 },
 119         { .temp_c       = 5, .ohm       = 94287 },
 120         { .temp_c       = 10, .ohm      = 71747 },
 121         { .temp_c       = 15, .ohm      = 54996 },
 122         { .temp_c       = 20, .ohm      = 42455 },
 123         { .temp_c       = 25, .ohm      = 33000 },
 124         { .temp_c       = 30, .ohm      = 25822 },
 125         { .temp_c       = 35, .ohm      = 20335 },
 126         { .temp_c       = 40, .ohm      = 16115 },
 127         { .temp_c       = 45, .ohm      = 12849 },
 128         { .temp_c       = 50, .ohm      = 10306 },
 129         { .temp_c       = 55, .ohm      = 8314 },
 130         { .temp_c       = 60, .ohm      = 6746 },
 131         { .temp_c       = 65, .ohm      = 5503 },
 132         { .temp_c       = 70, .ohm      = 4513 },
 133         { .temp_c       = 75, .ohm      = 3721 },
 134         { .temp_c       = 80, .ohm      = 3084 },
 135         { .temp_c       = 85, .ohm      = 2569 },
 136         { .temp_c       = 90, .ohm      = 2151 },
 137         { .temp_c       = 95, .ohm      = 1809 },
 138         { .temp_c       = 100, .ohm     = 1529 },
 139         { .temp_c       = 105, .ohm     = 1299 },
 140         { .temp_c       = 110, .ohm     = 1108 },
 141         { .temp_c       = 115, .ohm     = 949 },
 142         { .temp_c       = 120, .ohm     = 817 },
 143         { .temp_c       = 125, .ohm     = 707 },
 144 };
 145
 146 static const struct ntc_compensation ncpXXwf104[] = {
 147         { .temp_c       = -40, .ohm     = 4397119 },
 148         { .temp_c       = -35, .ohm     = 3088599 },
 149         { .temp_c       = -30, .ohm     = 2197225 },
 150         { .temp_c       = -25, .ohm     = 1581881 },
 151         { .temp_c       = -20, .ohm     = 1151037 },
 152         { .temp_c       = -15, .ohm     = 846579 },
 153         { .temp_c       = -10, .ohm     = 628988 },
 154         { .temp_c       = -5, .ohm      = 471632 },
 155         { .temp_c       = 0, .ohm       = 357012 },
 156         { .temp_c       = 5, .ohm       = 272500 },
 157         { .temp_c       = 10, .ohm      = 209710 },
 158         { .temp_c       = 15, .ohm      = 162651 },
 159         { .temp_c       = 20, .ohm      = 127080 },
 160         { .temp_c       = 25, .ohm      = 100000 },
 161         { .temp_c       = 30, .ohm      = 79222 },
 162         { .temp_c       = 35, .ohm      = 63167 },
 163         { .temp_c       = 40, .ohm      = 50677 },
 164         { .temp_c       = 45, .ohm      = 40904 },
 165         { .temp_c       = 50, .ohm      = 33195 },
 166         { .temp_c       = 55, .ohm      = 27091 },
 167         { .temp_c       = 60, .ohm      = 22224 },
 168         { .temp_c       = 65, .ohm      = 18323 },
 169         { .temp_c       = 70, .ohm      = 15184 },
 170         { .temp_c       = 75, .ohm      = 12635 },
 171         { .temp_c       = 80, .ohm      = 10566 },
 172         { .temp_c       = 85, .ohm      = 8873 },
 173         { .temp_c       = 90, .ohm      = 7481 },
 174         { .temp_c       = 95, .ohm      = 6337 },
 175         { .temp_c       = 100, .ohm     = 5384 },
 176         { .temp_c       = 105, .ohm     = 4594 },
 177         { .temp_c       = 110, .ohm     = 3934 },
 178         { .temp_c       = 115, .ohm     = 3380 },
 179         { .temp_c       = 120, .ohm     = 2916 },
 180         { .temp_c       = 125, .ohm     = 2522 },
 181 };
 182
 183 static const struct ntc_compensation ncpXXxh103[] = {
 184         { .temp_c       = -40, .ohm     = 247565 },
 185         { .temp_c       = -35, .ohm     = 181742 },
 186         { .temp_c       = -30, .ohm     = 135128 },
 187         { .temp_c       = -25, .ohm     = 101678 },
 188         { .temp_c       = -20, .ohm     = 77373 },
 189         { .temp_c       = -15, .ohm     = 59504 },
 190         { .temp_c       = -10, .ohm     = 46222 },
 191         { .temp_c       = -5, .ohm      = 36244 },
 192         { .temp_c       = 0, .ohm       = 28674 },
 193         { .temp_c       = 5, .ohm       = 22878 },
 194         { .temp_c       = 10, .ohm      = 18399 },
 195         { .temp_c       = 15, .ohm      = 14910 },
 196         { .temp_c       = 20, .ohm      = 12169 },
 197         { .temp_c       = 25, .ohm      = 10000 },
 198         { .temp_c       = 30, .ohm      = 8271 },
 199         { .temp_c       = 35, .ohm      = 6883 },
 200         { .temp_c       = 40, .ohm      = 5762 },
 201         { .temp_c       = 45, .ohm      = 4851 },
 202         { .temp_c       = 50, .ohm      = 4105 },
 203         { .temp_c       = 55, .ohm      = 3492 },
 204         { .temp_c       = 60, .ohm      = 2985 },
 205         { .temp_c       = 65, .ohm      = 2563 },
 206         { .temp_c       = 70, .ohm      = 2211 },
 207         { .temp_c       = 75, .ohm      = 1915 },
 208         { .temp_c       = 80, .ohm      = 1666 },
 209         { .temp_c       = 85, .ohm      = 1454 },
 210         { .temp_c       = 90, .ohm      = 1275 },
 211         { .temp_c       = 95, .ohm      = 1121 },
 212         { .temp_c       = 100, .ohm     = 990 },
 213         { .temp_c       = 105, .ohm     = 876 },
 214         { .temp_c       = 110, .ohm     = 779 },
 215         { .temp_c       = 115, .ohm     = 694 },
 216         { .temp_c       = 120, .ohm     = 620 },
 217         { .temp_c       = 125, .ohm     = 556 },
 218 };
 219
 220 /*
 221  * The following compensation tables are from the specifications in EPCOS NTC
 222  * Thermistors Datasheets
 223  */
 224 static const struct ntc_compensation b57330v2103[] = {
 225         { .temp_c       = -40, .ohm     = 190030 },
 226         { .temp_c       = -35, .ohm     = 145360 },
 227         { .temp_c       = -30, .ohm     = 112060 },
 228         { .temp_c       = -25, .ohm     = 87041 },
 229         { .temp_c       = -20, .ohm     = 68104 },
 230         { .temp_c       = -15, .ohm     = 53665 },
 231         { .temp_c       = -10, .ohm     = 42576 },
 232         { .temp_c       = -5, .ohm      = 34001 },
 233         { .temp_c       = 0, .ohm       = 27326 },
 234         { .temp_c       = 5, .ohm       = 22096 },
 235         { .temp_c       = 10, .ohm      = 17973 },
 236         { .temp_c       = 15, .ohm      = 14703 },
 237         { .temp_c       = 20, .ohm      = 12090 },
 238         { .temp_c       = 25, .ohm      = 10000 },
 239         { .temp_c       = 30, .ohm      = 8311 },
 240         { .temp_c       = 35, .ohm      = 6941 },
 241         { .temp_c       = 40, .ohm      = 5825 },
 242         { .temp_c       = 45, .ohm      = 4911 },
 243         { .temp_c       = 50, .ohm      = 4158 },
 244         { .temp_c       = 55, .ohm      = 3536 },
 245         { .temp_c       = 60, .ohm      = 3019 },
 246         { .temp_c       = 65, .ohm      = 2588 },
 247         { .temp_c       = 70, .ohm      = 2227 },
 248         { .temp_c       = 75, .ohm      = 1924 },
 249         { .temp_c       = 80, .ohm      = 1668 },
 250         { .temp_c       = 85, .ohm      = 1451 },
 251         { .temp_c       = 90, .ohm      = 1266 },
 252         { .temp_c       = 95, .ohm      = 1108 },
 253         { .temp_c       = 100, .ohm     = 973 },
 254         { .temp_c       = 105, .ohm     = 857 },
 255         { .temp_c       = 110, .ohm     = 757 },
 256         { .temp_c       = 115, .ohm     = 671 },
 257         { .temp_c       = 120, .ohm     = 596 },
 258         { .temp_c       = 125, .ohm     = 531 },
 259 };
 260
 261 static const struct ntc_compensation b57891s0103[] = {
 262         { .temp_c       = -55.0, .ohm   = 878900 },
 263         { .temp_c       = -50.0, .ohm   = 617590 },
 264         { .temp_c       = -45.0, .ohm   = 439340 },
 265         { .temp_c       = -40.0, .ohm   = 316180 },
 266         { .temp_c       = -35.0, .ohm   = 230060 },
 267         { .temp_c       = -30.0, .ohm   = 169150 },
 268         { .temp_c       = -25.0, .ohm   = 125550 },
 269         { .temp_c       = -20.0, .ohm   = 94143 },
 270         { .temp_c       = -15.0, .ohm   = 71172 },
 271         { .temp_c       = -10.0, .ohm   = 54308 },
 272         { .temp_c       = -5.0, .ohm    = 41505 },
 273         { .temp_c       = 0.0, .ohm     = 32014 },
 274         { .temp_c       = 5.0, .ohm     = 25011 },
 275         { .temp_c       = 10.0, .ohm    = 19691 },
 276         { .temp_c       = 15.0, .ohm    = 15618 },
 277         { .temp_c       = 20.0, .ohm    = 12474 },
 278         { .temp_c       = 25.0, .ohm    = 10000 },
 279         { .temp_c       = 30.0, .ohm    = 8080 },
 280         { .temp_c       = 35.0, .ohm    = 6569 },
 281         { .temp_c       = 40.0, .ohm    = 5372 },
 282         { .temp_c       = 45.0, .ohm    = 4424 },
 283         { .temp_c       = 50.0, .ohm    = 3661 },
 284         { .temp_c       = 55.0, .ohm    = 3039 },
 285         { .temp_c       = 60.0, .ohm    = 2536 },
 286         { .temp_c       = 65.0, .ohm    = 2128 },
 287         { .temp_c       = 70.0, .ohm    = 1794 },
 288         { .temp_c       = 75.0, .ohm    = 1518 },
 289         { .temp_c       = 80.0, .ohm    = 1290 },
 290         { .temp_c       = 85.0, .ohm    = 1100 },
 291         { .temp_c       = 90.0, .ohm    = 942 },
 292         { .temp_c       = 95.0, .ohm    = 809 },
 293         { .temp_c       = 100.0, .ohm   = 697 },
 294         { .temp_c       = 105.0, .ohm   = 604 },
 295         { .temp_c       = 110.0, .ohm   = 525 },
 296         { .temp_c       = 115.0, .ohm   = 457 },
 297         { .temp_c       = 120.0, .ohm   = 400 },
 298         { .temp_c       = 125.0, .ohm   = 351 },
 299         { .temp_c       = 130.0, .ohm   = 308 },
 300         { .temp_c       = 135.0, .ohm   = 272 },
 301         { .temp_c       = 140.0, .ohm   = 240 },
 302         { .temp_c       = 145.0, .ohm   = 213 },
 303         { .temp_c       = 150.0, .ohm   = 189 },
 304         { .temp_c       = 155.0, .ohm   = 168 },
 305 };
 306
 307 struct ntc_type {
 308         const struct ntc_compensation *comp;
 309         int n_comp;
 310 };
 311
 312 #define NTC_TYPE(ntc, compensation) \
 313 [(ntc)] = { .comp = (compensation), .n_comp = ARRAY_SIZE(compensation) }
 314
 315 static const struct ntc_type ntc_type[] = {
 316         NTC_TYPE(TYPE_B57330V2103, b57330v2103),
 317         NTC_TYPE(TYPE_B57891S0103, b57891s0103),
 318         NTC_TYPE(TYPE_NCPXXWB473,  ncpXXwb473),
 319         NTC_TYPE(TYPE_NCPXXWF104,  ncpXXwf104),
 320         NTC_TYPE(TYPE_NCPXXWL333,  ncpXXwl333),
 321         NTC_TYPE(TYPE_NCPXXXH103,  ncpXXxh103),
 322 };
 323
 324 /*
 325  * pullup_uV, pullup_ohm, pulldown_ohm, and connect are required.
 326  *
 327  * How to setup pullup_ohm, pulldown_ohm, and connect is
 328  * described at Documentation/hwmon/ntc_thermistor.rst
 329  *
 330  * pullup/down_ohm: 0 for infinite / not-connected
 331  *
 332  * chan: iio_channel pointer to communicate with the ADC which the
 333  * thermistor is using for conversion of the analog values.
 334  */
 335 struct ntc_data {
 336         const struct ntc_compensation *comp;
 337         int n_comp;
 338         unsigned int pullup_uv;
 339         unsigned int pullup_ohm;
 340         unsigned int pulldown_ohm;
 341         enum { NTC_CONNECTED_POSITIVE, NTC_CONNECTED_GROUND } connect;
 342         struct iio_channel *chan;
 343 };
 344
 345 static int ntc_adc_iio_read(struct ntc_data *data)
 346 {
 347         struct iio_channel *channel = data->chan;
 348         int uv, ret;
 349
 350         ret = iio_read_channel_processed_scale(channel, &uv, 1000);
 351         if (ret < 0) {
 352                 int raw;
 353
 354                 /*
 355                  * This fallback uses a raw read and then
 356                  * assumes the ADC is 12 bits, scaling with
 357                  * a factor 1000 to get to microvolts.
 358                  */
 359                 ret = iio_read_channel_raw(channel, &raw);
 360                 if (ret < 0) {
 361                         pr_err("read channel() error: %d\n", ret);
 362                         return ret;
 363                 }
 364                 ret = iio_convert_raw_to_processed(channel, raw, &uv, 1000);
 365                 if (ret < 0) {
 366                         /* Assume 12 bit ADC with vref at pullup_uv */
 367                         uv = (data->pullup_uv * (s64)raw) >> 12;
 368                 }
 369         }
 370
 371         return uv;
 372 }
 373
 374 static inline u64 div64_u64_safe(u64 dividend, u64 divisor)
 375 {
 376         if (divisor == 0 && dividend == 0)
 377                 return 0;
 378         if (divisor == 0)
 379                 return UINT_MAX;
 380         return div64_u64(dividend, divisor);
 381 }
 382
 383 static int get_ohm_of_thermistor(struct ntc_data *data, unsigned int uv)
 384 {
 385         u32 puv = data->pullup_uv;
 386         u64 n, puo, pdo;
 387         puo = data->pullup_ohm;
 388         pdo = data->pulldown_ohm;
 389
 390         if (uv == 0)
 391                 return (data->connect == NTC_CONNECTED_POSITIVE) ?
 392                         INT_MAX : 0;
 393         if (uv >= puv)
 394                 return (data->connect == NTC_CONNECTED_POSITIVE) ?
 395                         0 : INT_MAX;
 396
 397         if (data->connect == NTC_CONNECTED_POSITIVE && puo == 0)
 398                 n = div_u64(pdo * (puv - uv), uv);
 399         else if (data->connect == NTC_CONNECTED_GROUND && pdo == 0)
 400                 n = div_u64(puo * uv, puv - uv);
 401         else if (data->connect == NTC_CONNECTED_POSITIVE)
 402                 n = div64_u64_safe(pdo * puo * (puv - uv),
 403                                 puo * uv - pdo * (puv - uv));
 404         else
 405                 n = div64_u64_safe(pdo * puo * uv, pdo * (puv - uv) - puo * uv);
 406
 407         if (n > INT_MAX)
 408                 n = INT_MAX;
 409         return n;
 410 }
 411
 412 static void lookup_comp(struct ntc_data *data, unsigned int ohm,
 413                         int *i_low, int *i_high)
 414 {
 415         int start, end, mid;
 416
 417         /*
 418          * Handle special cases: Resistance is higher than or equal to
 419          * resistance in first table entry, or resistance is lower or equal
 420          * to resistance in last table entry.
 421          * In these cases, return i_low == i_high, either pointing to the
 422          * beginning or to the end of the table depending on the condition.
 423          */
 424         if (ohm >= data->comp[0].ohm) {
 425                 *i_low = 0;
 426                 *i_high = 0;
 427                 return;
 428         }
 429         if (ohm <= data->comp[data->n_comp - 1].ohm) {
 430                 *i_low = data->n_comp - 1;
 431                 *i_high = data->n_comp - 1;
 432                 return;
 433         }
 434
 435         /* Do a binary search on compensation table */
 436         start = 0;
 437         end = data->n_comp;
 438         while (start < end) {
 439                 mid = start + (end - start) / 2;
 440                 /*
 441                  * start <= mid < end
 442                  * data->comp[start].ohm > ohm >= data->comp[end].ohm
 443                  *
 444                  * We could check for "ohm == data->comp[mid].ohm" here, but
 445                  * that is a quite unlikely condition, and we would have to
 446                  * check again after updating start. Check it at the end instead
 447                  * for simplicity.
 448                  */
 449                 if (ohm >= data->comp[mid].ohm) {
 450                         end = mid;
 451                 } else {
 452                         start = mid + 1;
 453                         /*
 454                          * ohm >= data->comp[start].ohm might be true here,
 455                          * since we set start to mid + 1. In that case, we are
 456                          * done. We could keep going, but the condition is quite
 457                          * likely to occur, so it is worth checking for it.
 458                          */
 459                         if (ohm >= data->comp[start].ohm)
 460                                 end = start;
 461                 }
 462                 /*
 463                  * start <= end
 464                  * data->comp[start].ohm >= ohm >= data->comp[end].ohm
 465                  */
 466         }
 467         /*
 468          * start == end
 469          * ohm >= data->comp[end].ohm
 470          */
 471         *i_low = end;
 472         if (ohm == data->comp[end].ohm)
 473                 *i_high = end;
 474         else
 475                 *i_high = end - 1;
 476 }
 477
 478 static int get_temp_mc(struct ntc_data *data, unsigned int ohm)
 479 {
 480         int low, high;
 481         int temp;
 482
 483         lookup_comp(data, ohm, &low, &high);
 484         /*
 485          * First multiplying the table temperatures with 1000 to get to
 486          * millicentigrades (which is what we want) and then interpolating
 487          * will give the best precision.
 488          */
 489         temp = fixp_linear_interpolate(data->comp[low].ohm,
 490                                        data->comp[low].temp_c * 1000,
 491                                        data->comp[high].ohm,
 492                                        data->comp[high].temp_c * 1000,
 493                                        ohm);
 494         return temp;
 495 }
 496
 497 static int ntc_thermistor_get_ohm(struct ntc_data *data)
 498 {
 499         int read_uv;
 500
 501         read_uv = ntc_adc_iio_read(data);
 502         if (read_uv < 0)
 503                 return read_uv;
 504         return get_ohm_of_thermistor(data, read_uv);
 505 }
 506
 507 static int ntc_read(struct device *dev, enum hwmon_sensor_types type,
 508                     u32 attr, int channel, long *val)
 509 {
 510         struct ntc_data *data = dev_get_drvdata(dev);
 511         int ohm;
 512
 513         switch (type) {
 514         case hwmon_temp:
 515                 switch (attr) {
 516                 case hwmon_temp_input:
 517                         ohm = ntc_thermistor_get_ohm(data);
 518                         if (ohm < 0)
 519                                 return ohm;
 520                         *val = get_temp_mc(data, ohm);
 521                         return 0;
 522                 case hwmon_temp_type:
 523                         *val = 4;
 524                         return 0;
 525                 default:
 526                         break;
 527                 }
 528                 break;
 529         default:
 530                 break;
 531         }
 532         return -EINVAL;
 533 }
 534
 535 static umode_t ntc_is_visible(const void *data, enum hwmon_sensor_types type,
 536                               u32 attr, int channel)
 537 {
 538         if (type == hwmon_temp) {
 539                 switch (attr) {
 540                 case hwmon_temp_input:
 541                 case hwmon_temp_type:
 542                         return 0444;
 543                 default:
 544                         break;
 545                 }
 546         }
 547         return 0;
 548 }
 549
 550 static const struct hwmon_channel_info * const ntc_info[] = {
 551         HWMON_CHANNEL_INFO(chip, HWMON_C_REGISTER_TZ),
 552         HWMON_CHANNEL_INFO(temp, HWMON_T_INPUT | HWMON_T_TYPE),
 553         NULL
 554 };
 555
 556 static const struct hwmon_ops ntc_hwmon_ops = {
 557         .is_visible = ntc_is_visible,
 558         .read = ntc_read,
 559 };
 560
 561 static const struct hwmon_chip_info ntc_chip_info = {
 562         .ops = &ntc_hwmon_ops,
 563         .info = ntc_info,
 564 };
 565
 566 static int ntc_thermistor_parse_props(struct device *dev,
 567                                       struct ntc_data *data)
 568 {
 569         struct iio_channel *chan;
 570         enum iio_chan_type type;
 571         int ret;
 572
 573         chan = devm_iio_channel_get(dev, NULL);
 574         if (IS_ERR(chan))
 575                 return PTR_ERR(chan);
 576
 577         ret = iio_get_channel_type(chan, &type);
 578         if (ret < 0)
 579                 return ret;
 580
 581         if (type != IIO_VOLTAGE)
 582                 return -EINVAL;
 583
 584         ret = device_property_read_u32(dev, "pullup-uv", &data->pullup_uv);
 585         if (ret)
 586                 return dev_err_probe(dev,  ret, "pullup-uv not specified\n");
 587
 588         ret = device_property_read_u32(dev, "pullup-ohm", &data->pullup_ohm);
 589         if (ret)
 590                 return dev_err_probe(dev,  ret, "pullup-ohm not specified\n");
 591
 592         ret = device_property_read_u32(dev, "pulldown-ohm", &data->pulldown_ohm);
 593         if (ret)
 594                 return dev_err_probe(dev,  ret, "pulldown-ohm not specified\n");
 595
 596         if (device_property_read_bool(dev, "connected-positive"))
 597                 data->connect = NTC_CONNECTED_POSITIVE;
 598         else /* status change should be possible if not always on. */
 599                 data->connect = NTC_CONNECTED_GROUND;
 600
 601         data->chan = chan;
 602
 603         return 0;
 604 }
 605
 606 static int ntc_thermistor_probe(struct platform_device *pdev)
 607 {
 608         struct device *dev = &pdev->dev;
 609         const struct platform_device_id *pdev_id;
 610         struct device *hwmon_dev;
 611         struct ntc_data *data;
 612         int ret;
 613
 614         data = devm_kzalloc(dev, sizeof(*data), GFP_KERNEL);
 615         if (!data)
 616                 return -ENOMEM;
 617
 618         ret = ntc_thermistor_parse_props(dev, data);
 619         if (ret)
 620                 return ret;
 621
 622         if (data->pullup_uv == 0 ||
 623             (data->pullup_ohm == 0 && data->connect ==
 624              NTC_CONNECTED_GROUND) ||
 625             (data->pulldown_ohm == 0 && data->connect ==
 626              NTC_CONNECTED_POSITIVE) ||
 627             (data->connect != NTC_CONNECTED_POSITIVE &&
 628              data->connect != NTC_CONNECTED_GROUND)) {
 629                 dev_err(dev, "Required data to use NTC driver not supplied.\n");
 630                 return -EINVAL;
 631         }
 632
 633         pdev_id = device_get_match_data(dev);
 634
 635         if (pdev_id->driver_data >= ARRAY_SIZE(ntc_type)) {
 636                 dev_err(dev, "Unknown device type: %lu(%s)\n",
 637                                 pdev_id->driver_data, pdev_id->name);
 638                 return -EINVAL;
 639         }
 640
 641         data->comp   = ntc_type[pdev_id->driver_data].comp;
 642         data->n_comp = ntc_type[pdev_id->driver_data].n_comp;
 643
 644         hwmon_dev = devm_hwmon_device_register_with_info(dev, pdev_id->name,
 645                                                          data, &ntc_chip_info,
 646                                                          NULL);
 647         if (IS_ERR(hwmon_dev)) {
 648                 dev_err(dev, "unable to register as hwmon device.\n");
 649                 return PTR_ERR(hwmon_dev);
 650         }
 651
 652         dev_info(dev, "Thermistor type: %s successfully probed.\n",
 653                  pdev_id->name);
 654
 655         return 0;
 656 }
 657
 658 static const struct of_device_id ntc_match[] = {
 659         { .compatible = "epcos,b57330v2103",
 660                 .data = &ntc_thermistor_id[NTC_B57330V2103]},
 661         { .compatible = "epcos,b57891s0103",
 662                 .data = &ntc_thermistor_id[NTC_B57891S0103] },
 663         { .compatible = "murata,ncp03wb473",
 664                 .data = &ntc_thermistor_id[NTC_NCP03WB473] },
 665         { .compatible = "murata,ncp03wf104",
 666                 .data = &ntc_thermistor_id[NTC_NCP03WF104] },
 667         { .compatible = "murata,ncp15wb473",
 668                 .data = &ntc_thermistor_id[NTC_NCP15WB473] },
 669         { .compatible = "murata,ncp15wl333",
 670                 .data = &ntc_thermistor_id[NTC_NCP15WL333] },
 671         { .compatible = "murata,ncp15xh103",
 672                 .data = &ntc_thermistor_id[NTC_NCP15XH103] },
 673         { .compatible = "murata,ncp18wb473",
 674                 .data = &ntc_thermistor_id[NTC_NCP18WB473] },
 675         { .compatible = "murata,ncp21wb473",
 676                 .data = &ntc_thermistor_id[NTC_NCP21WB473] },
 677         { .compatible = "samsung,1404-001221",
 678                 .data = &ntc_thermistor_id[NTC_SSG1404001221] },
 679
 680         /* Usage of vendor name "ntc" is deprecated */
 681         { .compatible = "ntc,ncp03wb473",
 682                 .data = &ntc_thermistor_id[NTC_NCP03WB473] },
 683         { .compatible = "ntc,ncp15wb473",
 684                 .data = &ntc_thermistor_id[NTC_NCP15WB473] },
 685         { .compatible = "ntc,ncp15wl333",
 686                 .data = &ntc_thermistor_id[NTC_NCP15WL333] },
 687         { .compatible = "ntc,ncp18wb473",
 688                 .data = &ntc_thermistor_id[NTC_NCP18WB473] },
 689         { .compatible = "ntc,ncp21wb473",
 690                 .data = &ntc_thermistor_id[NTC_NCP21WB473] },
 691         { },
 692 };
 693 MODULE_DEVICE_TABLE(of, ntc_match);
 694
 695 static struct platform_driver ntc_thermistor_driver = {
 696         .driver = {
 697                 .name = "ntc-thermistor",
 698                 .of_match_table = ntc_match,
 699         },
 700         .probe = ntc_thermistor_probe,
 701         .id_table = ntc_thermistor_id,
 702 };
 703
 704 module_platform_driver(ntc_thermistor_driver);
 705
 706 MODULE_DESCRIPTION("NTC Thermistor Driver");
 707 MODULE_AUTHOR("MyungJoo Ham <myungjoo.ham@samsung.com>");
 708 MODULE_LICENSE("GPL");
 709 MODULE_ALIAS("platform:ntc-thermistor");