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/platform_device.h> 13 #include <linux/property.h> 14 #include <linux/err.h> 15 #include <linux/fixp-arith.h> 16 #include <linux/iio/consumer.h> 17 #include <linux/hwmon.h> 18 19 enum ntc_thermistor_type { 20 TYPE_B57330V2103, 21 TYPE_B57891S0103, 22 TYPE_NCPXXWB473, 23 TYPE_NCPXXWF104, 24 TYPE_NCPXXWL333, 25 TYPE_NCPXXXH103, 26 TYPE_NCPXXWM474, 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_NCP18WM474, 50 NTC_LAST, 51 }; 52 53 static const struct platform_device_id ntc_thermistor_id[] = { 54 [NTC_B57330V2103] = { .name = "b57330v2103", .driver_data = TYPE_B57330V2103 }, 55 [NTC_B57891S0103] = { .name = "b57891s0103", .driver_data = TYPE_B57891S0103 }, 56 [NTC_NCP03WB473] = { .name = "ncp03wb473", .driver_data = TYPE_NCPXXWB473 }, 57 [NTC_NCP03WF104] = { .name = "ncp03wf104", .driver_data = TYPE_NCPXXWF104 }, 58 [NTC_NCP15WB473] = { .name = "ncp15wb473", .driver_data = TYPE_NCPXXWB473 }, 59 [NTC_NCP15WL333] = { .name = "ncp15wl333", .driver_data = TYPE_NCPXXWL333 }, 60 [NTC_NCP15XH103] = { .name = "ncp15xh103", .driver_data = TYPE_NCPXXXH103 }, 61 [NTC_NCP18WB473] = { .name = "ncp18wb473", .driver_data = TYPE_NCPXXWB473 }, 62 [NTC_NCP21WB473] = { .name = "ncp21wb473", .driver_data = TYPE_NCPXXWB473 }, 63 [NTC_SSG1404001221] = { .name = "ssg1404_001221", .driver_data = TYPE_NCPXXWB473 }, 64 [NTC_NCP18WM474] = { .name = "ncp18wm474", .driver_data = TYPE_NCPXXWM474 }, 65 [NTC_LAST] = { } 66 }; 67 MODULE_DEVICE_TABLE(platform, ntc_thermistor_id); 68 69 /* 70 * A compensation table should be sorted by the values of .ohm 71 * in descending order. 72 * The following compensation tables are from the specification of Murata NTC 73 * Thermistors Datasheet 74 */ 75 static const struct ntc_compensation ncpXXwb473[] = { 76 { .temp_c = -40, .ohm = 1747920 }, 77 { .temp_c = -35, .ohm = 1245428 }, 78 { .temp_c = -30, .ohm = 898485 }, 79 { .temp_c = -25, .ohm = 655802 }, 80 { .temp_c = -20, .ohm = 483954 }, 81 { .temp_c = -15, .ohm = 360850 }, 82 { .temp_c = -10, .ohm = 271697 }, 83 { .temp_c = -5, .ohm = 206463 }, 84 { .temp_c = 0, .ohm = 158214 }, 85 { .temp_c = 5, .ohm = 122259 }, 86 { .temp_c = 10, .ohm = 95227 }, 87 { .temp_c = 15, .ohm = 74730 }, 88 { .temp_c = 20, .ohm = 59065 }, 89 { .temp_c = 25, .ohm = 47000 }, 90 { .temp_c = 30, .ohm = 37643 }, 91 { .temp_c = 35, .ohm = 30334 }, 92 { .temp_c = 40, .ohm = 24591 }, 93 { .temp_c = 45, .ohm = 20048 }, 94 { .temp_c = 50, .ohm = 16433 }, 95 { .temp_c = 55, .ohm = 13539 }, 96 { .temp_c = 60, .ohm = 11209 }, 97 { .temp_c = 65, .ohm = 9328 }, 98 { .temp_c = 70, .ohm = 7798 }, 99 { .temp_c = 75, .ohm = 6544 }, 100 { .temp_c = 80, .ohm = 5518 }, 101 { .temp_c = 85, .ohm = 4674 }, 102 { .temp_c = 90, .ohm = 3972 }, 103 { .temp_c = 95, .ohm = 3388 }, 104 { .temp_c = 100, .ohm = 2902 }, 105 { .temp_c = 105, .ohm = 2494 }, 106 { .temp_c = 110, .ohm = 2150 }, 107 { .temp_c = 115, .ohm = 1860 }, 108 { .temp_c = 120, .ohm = 1615 }, 109 { .temp_c = 125, .ohm = 1406 }, 110 }; 111 static const struct ntc_compensation ncpXXwl333[] = { 112 { .temp_c = -40, .ohm = 1610154 }, 113 { .temp_c = -35, .ohm = 1130850 }, 114 { .temp_c = -30, .ohm = 802609 }, 115 { .temp_c = -25, .ohm = 575385 }, 116 { .temp_c = -20, .ohm = 416464 }, 117 { .temp_c = -15, .ohm = 304219 }, 118 { .temp_c = -10, .ohm = 224193 }, 119 { .temp_c = -5, .ohm = 166623 }, 120 { .temp_c = 0, .ohm = 124850 }, 121 { .temp_c = 5, .ohm = 94287 }, 122 { .temp_c = 10, .ohm = 71747 }, 123 { .temp_c = 15, .ohm = 54996 }, 124 { .temp_c = 20, .ohm = 42455 }, 125 { .temp_c = 25, .ohm = 33000 }, 126 { .temp_c = 30, .ohm = 25822 }, 127 { .temp_c = 35, .ohm = 20335 }, 128 { .temp_c = 40, .ohm = 16115 }, 129 { .temp_c = 45, .ohm = 12849 }, 130 { .temp_c = 50, .ohm = 10306 }, 131 { .temp_c = 55, .ohm = 8314 }, 132 { .temp_c = 60, .ohm = 6746 }, 133 { .temp_c = 65, .ohm = 5503 }, 134 { .temp_c = 70, .ohm = 4513 }, 135 { .temp_c = 75, .ohm = 3721 }, 136 { .temp_c = 80, .ohm = 3084 }, 137 { .temp_c = 85, .ohm = 2569 }, 138 { .temp_c = 90, .ohm = 2151 }, 139 { .temp_c = 95, .ohm = 1809 }, 140 { .temp_c = 100, .ohm = 1529 }, 141 { .temp_c = 105, .ohm = 1299 }, 142 { .temp_c = 110, .ohm = 1108 }, 143 { .temp_c = 115, .ohm = 949 }, 144 { .temp_c = 120, .ohm = 817 }, 145 { .temp_c = 125, .ohm = 707 }, 146 }; 147 148 static const struct ntc_compensation ncpXXwf104[] = { 149 { .temp_c = -40, .ohm = 4397119 }, 150 { .temp_c = -35, .ohm = 3088599 }, 151 { .temp_c = -30, .ohm = 2197225 }, 152 { .temp_c = -25, .ohm = 1581881 }, 153 { .temp_c = -20, .ohm = 1151037 }, 154 { .temp_c = -15, .ohm = 846579 }, 155 { .temp_c = -10, .ohm = 628988 }, 156 { .temp_c = -5, .ohm = 471632 }, 157 { .temp_c = 0, .ohm = 357012 }, 158 { .temp_c = 5, .ohm = 272500 }, 159 { .temp_c = 10, .ohm = 209710 }, 160 { .temp_c = 15, .ohm = 162651 }, 161 { .temp_c = 20, .ohm = 127080 }, 162 { .temp_c = 25, .ohm = 100000 }, 163 { .temp_c = 30, .ohm = 79222 }, 164 { .temp_c = 35, .ohm = 63167 }, 165 { .temp_c = 40, .ohm = 50677 }, 166 { .temp_c = 45, .ohm = 40904 }, 167 { .temp_c = 50, .ohm = 33195 }, 168 { .temp_c = 55, .ohm = 27091 }, 169 { .temp_c = 60, .ohm = 22224 }, 170 { .temp_c = 65, .ohm = 18323 }, 171 { .temp_c = 70, .ohm = 15184 }, 172 { .temp_c = 75, .ohm = 12635 }, 173 { .temp_c = 80, .ohm = 10566 }, 174 { .temp_c = 85, .ohm = 8873 }, 175 { .temp_c = 90, .ohm = 7481 }, 176 { .temp_c = 95, .ohm = 6337 }, 177 { .temp_c = 100, .ohm = 5384 }, 178 { .temp_c = 105, .ohm = 4594 }, 179 { .temp_c = 110, .ohm = 3934 }, 180 { .temp_c = 115, .ohm = 3380 }, 181 { .temp_c = 120, .ohm = 2916 }, 182 { .temp_c = 125, .ohm = 2522 }, 183 }; 184 185 static const struct ntc_compensation ncpXXxh103[] = { 186 { .temp_c = -40, .ohm = 195652 }, 187 { .temp_c = -35, .ohm = 148171 }, 188 { .temp_c = -30, .ohm = 113347 }, 189 { .temp_c = -25, .ohm = 87559 }, 190 { .temp_c = -20, .ohm = 68237 }, 191 { .temp_c = -15, .ohm = 53650 }, 192 { .temp_c = -10, .ohm = 42506 }, 193 { .temp_c = -5, .ohm = 33892 }, 194 { .temp_c = 0, .ohm = 27219 }, 195 { .temp_c = 5, .ohm = 22021 }, 196 { .temp_c = 10, .ohm = 17926 }, 197 { .temp_c = 15, .ohm = 14674 }, 198 { .temp_c = 20, .ohm = 12081 }, 199 { .temp_c = 25, .ohm = 10000 }, 200 { .temp_c = 30, .ohm = 8315 }, 201 { .temp_c = 35, .ohm = 6948 }, 202 { .temp_c = 40, .ohm = 5834 }, 203 { .temp_c = 45, .ohm = 4917 }, 204 { .temp_c = 50, .ohm = 4161 }, 205 { .temp_c = 55, .ohm = 3535 }, 206 { .temp_c = 60, .ohm = 3014 }, 207 { .temp_c = 65, .ohm = 2586 }, 208 { .temp_c = 70, .ohm = 2228 }, 209 { .temp_c = 75, .ohm = 1925 }, 210 { .temp_c = 80, .ohm = 1669 }, 211 { .temp_c = 85, .ohm = 1452 }, 212 { .temp_c = 90, .ohm = 1268 }, 213 { .temp_c = 95, .ohm = 1110 }, 214 { .temp_c = 100, .ohm = 974 }, 215 { .temp_c = 105, .ohm = 858 }, 216 { .temp_c = 110, .ohm = 758 }, 217 { .temp_c = 115, .ohm = 672 }, 218 { .temp_c = 120, .ohm = 596 }, 219 { .temp_c = 125, .ohm = 531 }, 220 }; 221 222 static const struct ntc_compensation ncpXXwm474[] = { 223 { .temp_c = -40, .ohm = 10900000 }, 224 { .temp_c = -35, .ohm = 9600000 }, 225 { .temp_c = -30, .ohm = 8300000 }, 226 { .temp_c = -25, .ohm = 7000000 }, 227 { .temp_c = -20, .ohm = 5980000 }, 228 { .temp_c = -15, .ohm = 4960000 }, 229 { .temp_c = -10, .ohm = 3940000 }, 230 { .temp_c = -5, .ohm = 2920000 }, 231 { .temp_c = 0, .ohm = 1900000 }, 232 { .temp_c = 5, .ohm = 1614000 }, 233 { .temp_c = 10, .ohm = 1328000 }, 234 { .temp_c = 15, .ohm = 1042000 }, 235 { .temp_c = 20, .ohm = 756000 }, 236 { .temp_c = 25, .ohm = 470000 }, 237 { .temp_c = 30, .ohm = 404000 }, 238 { .temp_c = 35, .ohm = 338000 }, 239 { .temp_c = 40, .ohm = 272000 }, 240 { .temp_c = 45, .ohm = 206000 }, 241 { .temp_c = 50, .ohm = 140000 }, 242 { .temp_c = 55, .ohm = 122000 }, 243 { .temp_c = 60, .ohm = 104000 }, 244 { .temp_c = 65, .ohm = 86000 }, 245 { .temp_c = 70, .ohm = 68000 }, 246 { .temp_c = 75, .ohm = 50000 }, 247 { .temp_c = 80, .ohm = 44200 }, 248 { .temp_c = 85, .ohm = 38400 }, 249 { .temp_c = 90, .ohm = 32600 }, 250 { .temp_c = 95, .ohm = 26800 }, 251 { .temp_c = 100, .ohm = 21000 }, 252 { .temp_c = 105, .ohm = 18600 }, 253 { .temp_c = 110, .ohm = 16200 }, 254 { .temp_c = 115, .ohm = 13800 }, 255 { .temp_c = 120, .ohm = 11400 }, 256 { .temp_c = 125, .ohm = 9000 }, 257 }; 258 259 /* 260 * The following compensation tables are from the specifications in EPCOS NTC 261 * Thermistors Datasheets 262 */ 263 static const struct ntc_compensation b57330v2103[] = { 264 { .temp_c = -40, .ohm = 190030 }, 265 { .temp_c = -35, .ohm = 145360 }, 266 { .temp_c = -30, .ohm = 112060 }, 267 { .temp_c = -25, .ohm = 87041 }, 268 { .temp_c = -20, .ohm = 68104 }, 269 { .temp_c = -15, .ohm = 53665 }, 270 { .temp_c = -10, .ohm = 42576 }, 271 { .temp_c = -5, .ohm = 34001 }, 272 { .temp_c = 0, .ohm = 27326 }, 273 { .temp_c = 5, .ohm = 22096 }, 274 { .temp_c = 10, .ohm = 17973 }, 275 { .temp_c = 15, .ohm = 14703 }, 276 { .temp_c = 20, .ohm = 12090 }, 277 { .temp_c = 25, .ohm = 10000 }, 278 { .temp_c = 30, .ohm = 8311 }, 279 { .temp_c = 35, .ohm = 6941 }, 280 { .temp_c = 40, .ohm = 5825 }, 281 { .temp_c = 45, .ohm = 4911 }, 282 { .temp_c = 50, .ohm = 4158 }, 283 { .temp_c = 55, .ohm = 3536 }, 284 { .temp_c = 60, .ohm = 3019 }, 285 { .temp_c = 65, .ohm = 2588 }, 286 { .temp_c = 70, .ohm = 2227 }, 287 { .temp_c = 75, .ohm = 1924 }, 288 { .temp_c = 80, .ohm = 1668 }, 289 { .temp_c = 85, .ohm = 1451 }, 290 { .temp_c = 90, .ohm = 1266 }, 291 { .temp_c = 95, .ohm = 1108 }, 292 { .temp_c = 100, .ohm = 973 }, 293 { .temp_c = 105, .ohm = 857 }, 294 { .temp_c = 110, .ohm = 757 }, 295 { .temp_c = 115, .ohm = 671 }, 296 { .temp_c = 120, .ohm = 596 }, 297 { .temp_c = 125, .ohm = 531 }, 298 }; 299 300 static const struct ntc_compensation b57891s0103[] = { 301 { .temp_c = -55.0, .ohm = 878900 }, 302 { .temp_c = -50.0, .ohm = 617590 }, 303 { .temp_c = -45.0, .ohm = 439340 }, 304 { .temp_c = -40.0, .ohm = 316180 }, 305 { .temp_c = -35.0, .ohm = 230060 }, 306 { .temp_c = -30.0, .ohm = 169150 }, 307 { .temp_c = -25.0, .ohm = 125550 }, 308 { .temp_c = -20.0, .ohm = 94143 }, 309 { .temp_c = -15.0, .ohm = 71172 }, 310 { .temp_c = -10.0, .ohm = 54308 }, 311 { .temp_c = -5.0, .ohm = 41505 }, 312 { .temp_c = 0.0, .ohm = 32014 }, 313 { .temp_c = 5.0, .ohm = 25011 }, 314 { .temp_c = 10.0, .ohm = 19691 }, 315 { .temp_c = 15.0, .ohm = 15618 }, 316 { .temp_c = 20.0, .ohm = 12474 }, 317 { .temp_c = 25.0, .ohm = 10000 }, 318 { .temp_c = 30.0, .ohm = 8080 }, 319 { .temp_c = 35.0, .ohm = 6569 }, 320 { .temp_c = 40.0, .ohm = 5372 }, 321 { .temp_c = 45.0, .ohm = 4424 }, 322 { .temp_c = 50.0, .ohm = 3661 }, 323 { .temp_c = 55.0, .ohm = 3039 }, 324 { .temp_c = 60.0, .ohm = 2536 }, 325 { .temp_c = 65.0, .ohm = 2128 }, 326 { .temp_c = 70.0, .ohm = 1794 }, 327 { .temp_c = 75.0, .ohm = 1518 }, 328 { .temp_c = 80.0, .ohm = 1290 }, 329 { .temp_c = 85.0, .ohm = 1100 }, 330 { .temp_c = 90.0, .ohm = 942 }, 331 { .temp_c = 95.0, .ohm = 809 }, 332 { .temp_c = 100.0, .ohm = 697 }, 333 { .temp_c = 105.0, .ohm = 604 }, 334 { .temp_c = 110.0, .ohm = 525 }, 335 { .temp_c = 115.0, .ohm = 457 }, 336 { .temp_c = 120.0, .ohm = 400 }, 337 { .temp_c = 125.0, .ohm = 351 }, 338 { .temp_c = 130.0, .ohm = 308 }, 339 { .temp_c = 135.0, .ohm = 272 }, 340 { .temp_c = 140.0, .ohm = 240 }, 341 { .temp_c = 145.0, .ohm = 213 }, 342 { .temp_c = 150.0, .ohm = 189 }, 343 { .temp_c = 155.0, .ohm = 168 }, 344 }; 345 346 struct ntc_type { 347 const struct ntc_compensation *comp; 348 int n_comp; 349 }; 350 351 #define NTC_TYPE(ntc, compensation) \ 352 [(ntc)] = { .comp = (compensation), .n_comp = ARRAY_SIZE(compensation) } 353 354 static const struct ntc_type ntc_type[] = { 355 NTC_TYPE(TYPE_B57330V2103, b57330v2103), 356 NTC_TYPE(TYPE_B57891S0103, b57891s0103), 357 NTC_TYPE(TYPE_NCPXXWB473, ncpXXwb473), 358 NTC_TYPE(TYPE_NCPXXWF104, ncpXXwf104), 359 NTC_TYPE(TYPE_NCPXXWL333, ncpXXwl333), 360 NTC_TYPE(TYPE_NCPXXXH103, ncpXXxh103), 361 NTC_TYPE(TYPE_NCPXXWM474, ncpXXwm474), 362 }; 363 364 /* 365 * pullup_uV, pullup_ohm, pulldown_ohm, and connect are required. 366 * 367 * How to setup pullup_ohm, pulldown_ohm, and connect is 368 * described at Documentation/hwmon/ntc_thermistor.rst 369 * 370 * pullup/down_ohm: 0 for infinite / not-connected 371 * 372 * chan: iio_channel pointer to communicate with the ADC which the 373 * thermistor is using for conversion of the analog values. 374 */ 375 struct ntc_data { 376 const struct ntc_compensation *comp; 377 int n_comp; 378 unsigned int pullup_uv; 379 unsigned int pullup_ohm; 380 unsigned int pulldown_ohm; 381 enum { NTC_CONNECTED_POSITIVE, NTC_CONNECTED_GROUND } connect; 382 struct iio_channel *chan; 383 }; 384 385 static int ntc_adc_iio_read(struct ntc_data *data) 386 { 387 struct iio_channel *channel = data->chan; 388 int uv, ret; 389 390 ret = iio_read_channel_processed_scale(channel, &uv, 1000); 391 if (ret < 0) { 392 int raw; 393 394 /* 395 * This fallback uses a raw read and then 396 * assumes the ADC is 12 bits, scaling with 397 * a factor 1000 to get to microvolts. 398 */ 399 ret = iio_read_channel_raw(channel, &raw); 400 if (ret < 0) { 401 pr_err("read channel() error: %d\n", ret); 402 return ret; 403 } 404 ret = iio_convert_raw_to_processed(channel, raw, &uv, 1000); 405 if (ret < 0) { 406 /* Assume 12 bit ADC with vref at pullup_uv */ 407 uv = (data->pullup_uv * (s64)raw) >> 12; 408 } 409 } 410 411 return uv; 412 } 413 414 static inline u64 div64_u64_safe(u64 dividend, u64 divisor) 415 { 416 if (divisor == 0 && dividend == 0) 417 return 0; 418 if (divisor == 0) 419 return UINT_MAX; 420 return div64_u64(dividend, divisor); 421 } 422 423 static int get_ohm_of_thermistor(struct ntc_data *data, unsigned int uv) 424 { 425 u32 puv = data->pullup_uv; 426 u64 n, puo, pdo; 427 puo = data->pullup_ohm; 428 pdo = data->pulldown_ohm; 429 430 /* faulty adc value */ 431 if (uv == 0 || uv >= puv) 432 return -ENODATA; 433 434 if (data->connect == NTC_CONNECTED_POSITIVE && puo == 0) 435 n = div_u64(pdo * (puv - uv), uv); 436 else if (data->connect == NTC_CONNECTED_GROUND && pdo == 0) 437 n = div_u64(puo * uv, puv - uv); 438 else if (data->connect == NTC_CONNECTED_POSITIVE) 439 n = div64_u64_safe(pdo * puo * (puv - uv), 440 puo * uv - pdo * (puv - uv)); 441 else 442 n = div64_u64_safe(pdo * puo * uv, pdo * (puv - uv) - puo * uv); 443 444 /* sensor out of bounds */ 445 if (n > data->comp[0].ohm || n < data->comp[data->n_comp - 1].ohm) 446 return -ENODATA; 447 448 return n; 449 } 450 451 static void lookup_comp(struct ntc_data *data, unsigned int ohm, 452 int *i_low, int *i_high) 453 { 454 int start, end, mid; 455 456 /* 457 * Handle special cases: Resistance is higher than or equal to 458 * resistance in first table entry, or resistance is lower or equal 459 * to resistance in last table entry. 460 * In these cases, return i_low == i_high, either pointing to the 461 * beginning or to the end of the table depending on the condition. 462 */ 463 if (ohm >= data->comp[0].ohm) { 464 *i_low = 0; 465 *i_high = 0; 466 return; 467 } 468 if (ohm <= data->comp[data->n_comp - 1].ohm) { 469 *i_low = data->n_comp - 1; 470 *i_high = data->n_comp - 1; 471 return; 472 } 473 474 /* Do a binary search on compensation table */ 475 start = 0; 476 end = data->n_comp; 477 while (start < end) { 478 mid = start + (end - start) / 2; 479 /* 480 * start <= mid < end 481 * data->comp[start].ohm > ohm >= data->comp[end].ohm 482 * 483 * We could check for "ohm == data->comp[mid].ohm" here, but 484 * that is a quite unlikely condition, and we would have to 485 * check again after updating start. Check it at the end instead 486 * for simplicity. 487 */ 488 if (ohm >= data->comp[mid].ohm) { 489 end = mid; 490 } else { 491 start = mid + 1; 492 /* 493 * ohm >= data->comp[start].ohm might be true here, 494 * since we set start to mid + 1. In that case, we are 495 * done. We could keep going, but the condition is quite 496 * likely to occur, so it is worth checking for it. 497 */ 498 if (ohm >= data->comp[start].ohm) 499 end = start; 500 } 501 /* 502 * start <= end 503 * data->comp[start].ohm >= ohm >= data->comp[end].ohm 504 */ 505 } 506 /* 507 * start == end 508 * ohm >= data->comp[end].ohm 509 */ 510 *i_low = end; 511 if (ohm == data->comp[end].ohm) 512 *i_high = end; 513 else 514 *i_high = end - 1; 515 } 516 517 static int get_temp_mc(struct ntc_data *data, unsigned int ohm) 518 { 519 int low, high; 520 int temp; 521 522 lookup_comp(data, ohm, &low, &high); 523 /* 524 * First multiplying the table temperatures with 1000 to get to 525 * millicentigrades (which is what we want) and then interpolating 526 * will give the best precision. 527 */ 528 temp = fixp_linear_interpolate(data->comp[low].ohm, 529 data->comp[low].temp_c * 1000, 530 data->comp[high].ohm, 531 data->comp[high].temp_c * 1000, 532 ohm); 533 return temp; 534 } 535 536 static int ntc_thermistor_get_ohm(struct ntc_data *data) 537 { 538 int read_uv; 539 540 read_uv = ntc_adc_iio_read(data); 541 if (read_uv < 0) 542 return read_uv; 543 return get_ohm_of_thermistor(data, read_uv); 544 } 545 546 static int ntc_read(struct device *dev, enum hwmon_sensor_types type, 547 u32 attr, int channel, long *val) 548 { 549 struct ntc_data *data = dev_get_drvdata(dev); 550 int ohm; 551 552 switch (type) { 553 case hwmon_temp: 554 switch (attr) { 555 case hwmon_temp_input: 556 ohm = ntc_thermistor_get_ohm(data); 557 if (ohm < 0) 558 return ohm; 559 *val = get_temp_mc(data, ohm); 560 return 0; 561 case hwmon_temp_type: 562 *val = 4; 563 return 0; 564 default: 565 break; 566 } 567 break; 568 default: 569 break; 570 } 571 return -EINVAL; 572 } 573 574 static umode_t ntc_is_visible(const void *data, enum hwmon_sensor_types type, 575 u32 attr, int channel) 576 { 577 if (type == hwmon_temp) { 578 switch (attr) { 579 case hwmon_temp_input: 580 case hwmon_temp_type: 581 return 0444; 582 default: 583 break; 584 } 585 } 586 return 0; 587 } 588 589 static const struct hwmon_channel_info * const ntc_info[] = { 590 HWMON_CHANNEL_INFO(chip, HWMON_C_REGISTER_TZ), 591 HWMON_CHANNEL_INFO(temp, HWMON_T_INPUT | HWMON_T_TYPE), 592 NULL 593 }; 594 595 static const struct hwmon_ops ntc_hwmon_ops = { 596 .is_visible = ntc_is_visible, 597 .read = ntc_read, 598 }; 599 600 static const struct hwmon_chip_info ntc_chip_info = { 601 .ops = &ntc_hwmon_ops, 602 .info = ntc_info, 603 }; 604 605 static int ntc_thermistor_parse_props(struct device *dev, 606 struct ntc_data *data) 607 { 608 struct iio_channel *chan; 609 enum iio_chan_type type; 610 int ret; 611 612 chan = devm_iio_channel_get(dev, NULL); 613 if (IS_ERR(chan)) 614 return PTR_ERR(chan); 615 616 ret = iio_get_channel_type(chan, &type); 617 if (ret < 0) 618 return ret; 619 620 if (type != IIO_VOLTAGE) 621 return -EINVAL; 622 623 ret = device_property_read_u32(dev, "pullup-uv", &data->pullup_uv); 624 if (ret) 625 return dev_err_probe(dev, ret, "pullup-uv not specified\n"); 626 627 ret = device_property_read_u32(dev, "pullup-ohm", &data->pullup_ohm); 628 if (ret) 629 return dev_err_probe(dev, ret, "pullup-ohm not specified\n"); 630 631 ret = device_property_read_u32(dev, "pulldown-ohm", &data->pulldown_ohm); 632 if (ret) 633 return dev_err_probe(dev, ret, "pulldown-ohm not specified\n"); 634 635 if (device_property_read_bool(dev, "connected-positive")) 636 data->connect = NTC_CONNECTED_POSITIVE; 637 else /* status change should be possible if not always on. */ 638 data->connect = NTC_CONNECTED_GROUND; 639 640 data->chan = chan; 641 642 return 0; 643 } 644 645 static int ntc_thermistor_probe(struct platform_device *pdev) 646 { 647 struct device *dev = &pdev->dev; 648 const struct platform_device_id *pdev_id; 649 struct device *hwmon_dev; 650 struct ntc_data *data; 651 int ret; 652 653 data = devm_kzalloc(dev, sizeof(*data), GFP_KERNEL); 654 if (!data) 655 return -ENOMEM; 656 657 ret = ntc_thermistor_parse_props(dev, data); 658 if (ret) 659 return ret; 660 661 if (data->pullup_uv == 0 || 662 (data->pullup_ohm == 0 && data->connect == 663 NTC_CONNECTED_GROUND) || 664 (data->pulldown_ohm == 0 && data->connect == 665 NTC_CONNECTED_POSITIVE) || 666 (data->connect != NTC_CONNECTED_POSITIVE && 667 data->connect != NTC_CONNECTED_GROUND)) { 668 dev_err(dev, "Required data to use NTC driver not supplied.\n"); 669 return -EINVAL; 670 } 671 672 pdev_id = device_get_match_data(dev); 673 674 if (pdev_id->driver_data >= ARRAY_SIZE(ntc_type)) { 675 dev_err(dev, "Unknown device type: %lu(%s)\n", 676 pdev_id->driver_data, pdev_id->name); 677 return -EINVAL; 678 } 679 680 data->comp = ntc_type[pdev_id->driver_data].comp; 681 data->n_comp = ntc_type[pdev_id->driver_data].n_comp; 682 683 hwmon_dev = devm_hwmon_device_register_with_info(dev, pdev_id->name, 684 data, &ntc_chip_info, 685 NULL); 686 if (IS_ERR(hwmon_dev)) { 687 dev_err(dev, "unable to register as hwmon device.\n"); 688 return PTR_ERR(hwmon_dev); 689 } 690 691 dev_info(dev, "Thermistor type: %s successfully probed.\n", 692 pdev_id->name); 693 694 return 0; 695 } 696 697 static const struct of_device_id ntc_match[] = { 698 { .compatible = "epcos,b57330v2103", 699 .data = &ntc_thermistor_id[NTC_B57330V2103]}, 700 { .compatible = "epcos,b57891s0103", 701 .data = &ntc_thermistor_id[NTC_B57891S0103] }, 702 { .compatible = "murata,ncp03wb473", 703 .data = &ntc_thermistor_id[NTC_NCP03WB473] }, 704 { .compatible = "murata,ncp03wf104", 705 .data = &ntc_thermistor_id[NTC_NCP03WF104] }, 706 { .compatible = "murata,ncp15wb473", 707 .data = &ntc_thermistor_id[NTC_NCP15WB473] }, 708 { .compatible = "murata,ncp15wl333", 709 .data = &ntc_thermistor_id[NTC_NCP15WL333] }, 710 { .compatible = "murata,ncp15xh103", 711 .data = &ntc_thermistor_id[NTC_NCP15XH103] }, 712 { .compatible = "murata,ncp18wb473", 713 .data = &ntc_thermistor_id[NTC_NCP18WB473] }, 714 { .compatible = "murata,ncp21wb473", 715 .data = &ntc_thermistor_id[NTC_NCP21WB473] }, 716 { .compatible = "samsung,1404-001221", 717 .data = &ntc_thermistor_id[NTC_SSG1404001221] }, 718 { .compatible = "murata,ncp18wm474", 719 .data = &ntc_thermistor_id[NTC_NCP18WM474] }, 720 721 /* Usage of vendor name "ntc" is deprecated */ 722 { .compatible = "ntc,ncp03wb473", 723 .data = &ntc_thermistor_id[NTC_NCP03WB473] }, 724 { .compatible = "ntc,ncp15wb473", 725 .data = &ntc_thermistor_id[NTC_NCP15WB473] }, 726 { .compatible = "ntc,ncp15wl333", 727 .data = &ntc_thermistor_id[NTC_NCP15WL333] }, 728 { .compatible = "ntc,ncp18wb473", 729 .data = &ntc_thermistor_id[NTC_NCP18WB473] }, 730 { .compatible = "ntc,ncp21wb473", 731 .data = &ntc_thermistor_id[NTC_NCP21WB473] }, 732 { }, 733 }; 734 MODULE_DEVICE_TABLE(of, ntc_match); 735 736 static struct platform_driver ntc_thermistor_driver = { 737 .driver = { 738 .name = "ntc-thermistor", 739 .of_match_table = ntc_match, 740 }, 741 .probe = ntc_thermistor_probe, 742 .id_table = ntc_thermistor_id, 743 }; 744 745 module_platform_driver(ntc_thermistor_driver); 746 747 MODULE_DESCRIPTION("NTC Thermistor Driver"); 748 MODULE_AUTHOR("MyungJoo Ham <myungjoo.ham@samsung.com>"); 749 MODULE_LICENSE("GPL"); 750 MODULE_ALIAS("platform:ntc-thermistor"); 751 MODULE_IMPORT_NS("IIO_CONSUMER"); 752