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/pm_runtime.h> 12 #include <linux/math64.h> 13 #include <linux/platform_device.h> 14 #include <linux/err.h> 15 #include <linux/of.h> 16 #include <linux/of_device.h> 17 18 #include <linux/platform_data/ntc_thermistor.h> 19 20 #include <linux/iio/iio.h> 21 #include <linux/iio/machine.h> 22 #include <linux/iio/driver.h> 23 #include <linux/iio/consumer.h> 24 25 #include <linux/hwmon.h> 26 27 struct ntc_compensation { 28 int temp_c; 29 unsigned int ohm; 30 }; 31 32 /* 33 * Used as index in a zero-terminated array, holes not allowed so 34 * that NTC_LAST is the first empty array entry. 35 */ 36 enum { 37 NTC_B57330V2103, 38 NTC_B57891S0103, 39 NTC_NCP03WB473, 40 NTC_NCP03WF104, 41 NTC_NCP15WB473, 42 NTC_NCP15WL333, 43 NTC_NCP15XH103, 44 NTC_NCP18WB473, 45 NTC_NCP21WB473, 46 NTC_LAST, 47 }; 48 49 static const struct platform_device_id ntc_thermistor_id[] = { 50 [NTC_B57330V2103] = { "b57330v2103", TYPE_B57330V2103 }, 51 [NTC_B57891S0103] = { "b57891s0103", TYPE_B57891S0103 }, 52 [NTC_NCP03WB473] = { "ncp03wb473", TYPE_NCPXXWB473 }, 53 [NTC_NCP03WF104] = { "ncp03wf104", TYPE_NCPXXWF104 }, 54 [NTC_NCP15WB473] = { "ncp15wb473", TYPE_NCPXXWB473 }, 55 [NTC_NCP15WL333] = { "ncp15wl333", TYPE_NCPXXWL333 }, 56 [NTC_NCP15XH103] = { "ncp15xh103", TYPE_NCPXXXH103 }, 57 [NTC_NCP18WB473] = { "ncp18wb473", TYPE_NCPXXWB473 }, 58 [NTC_NCP21WB473] = { "ncp21wb473", TYPE_NCPXXWB473 }, 59 [NTC_LAST] = { }, 60 }; 61 62 /* 63 * A compensation table should be sorted by the values of .ohm 64 * in descending order. 65 * The following compensation tables are from the specification of Murata NTC 66 * Thermistors Datasheet 67 */ 68 static const struct ntc_compensation ncpXXwb473[] = { 69 { .temp_c = -40, .ohm = 1747920 }, 70 { .temp_c = -35, .ohm = 1245428 }, 71 { .temp_c = -30, .ohm = 898485 }, 72 { .temp_c = -25, .ohm = 655802 }, 73 { .temp_c = -20, .ohm = 483954 }, 74 { .temp_c = -15, .ohm = 360850 }, 75 { .temp_c = -10, .ohm = 271697 }, 76 { .temp_c = -5, .ohm = 206463 }, 77 { .temp_c = 0, .ohm = 158214 }, 78 { .temp_c = 5, .ohm = 122259 }, 79 { .temp_c = 10, .ohm = 95227 }, 80 { .temp_c = 15, .ohm = 74730 }, 81 { .temp_c = 20, .ohm = 59065 }, 82 { .temp_c = 25, .ohm = 47000 }, 83 { .temp_c = 30, .ohm = 37643 }, 84 { .temp_c = 35, .ohm = 30334 }, 85 { .temp_c = 40, .ohm = 24591 }, 86 { .temp_c = 45, .ohm = 20048 }, 87 { .temp_c = 50, .ohm = 16433 }, 88 { .temp_c = 55, .ohm = 13539 }, 89 { .temp_c = 60, .ohm = 11209 }, 90 { .temp_c = 65, .ohm = 9328 }, 91 { .temp_c = 70, .ohm = 7798 }, 92 { .temp_c = 75, .ohm = 6544 }, 93 { .temp_c = 80, .ohm = 5518 }, 94 { .temp_c = 85, .ohm = 4674 }, 95 { .temp_c = 90, .ohm = 3972 }, 96 { .temp_c = 95, .ohm = 3388 }, 97 { .temp_c = 100, .ohm = 2902 }, 98 { .temp_c = 105, .ohm = 2494 }, 99 { .temp_c = 110, .ohm = 2150 }, 100 { .temp_c = 115, .ohm = 1860 }, 101 { .temp_c = 120, .ohm = 1615 }, 102 { .temp_c = 125, .ohm = 1406 }, 103 }; 104 static const struct ntc_compensation ncpXXwl333[] = { 105 { .temp_c = -40, .ohm = 1610154 }, 106 { .temp_c = -35, .ohm = 1130850 }, 107 { .temp_c = -30, .ohm = 802609 }, 108 { .temp_c = -25, .ohm = 575385 }, 109 { .temp_c = -20, .ohm = 416464 }, 110 { .temp_c = -15, .ohm = 304219 }, 111 { .temp_c = -10, .ohm = 224193 }, 112 { .temp_c = -5, .ohm = 166623 }, 113 { .temp_c = 0, .ohm = 124850 }, 114 { .temp_c = 5, .ohm = 94287 }, 115 { .temp_c = 10, .ohm = 71747 }, 116 { .temp_c = 15, .ohm = 54996 }, 117 { .temp_c = 20, .ohm = 42455 }, 118 { .temp_c = 25, .ohm = 33000 }, 119 { .temp_c = 30, .ohm = 25822 }, 120 { .temp_c = 35, .ohm = 20335 }, 121 { .temp_c = 40, .ohm = 16115 }, 122 { .temp_c = 45, .ohm = 12849 }, 123 { .temp_c = 50, .ohm = 10306 }, 124 { .temp_c = 55, .ohm = 8314 }, 125 { .temp_c = 60, .ohm = 6746 }, 126 { .temp_c = 65, .ohm = 5503 }, 127 { .temp_c = 70, .ohm = 4513 }, 128 { .temp_c = 75, .ohm = 3721 }, 129 { .temp_c = 80, .ohm = 3084 }, 130 { .temp_c = 85, .ohm = 2569 }, 131 { .temp_c = 90, .ohm = 2151 }, 132 { .temp_c = 95, .ohm = 1809 }, 133 { .temp_c = 100, .ohm = 1529 }, 134 { .temp_c = 105, .ohm = 1299 }, 135 { .temp_c = 110, .ohm = 1108 }, 136 { .temp_c = 115, .ohm = 949 }, 137 { .temp_c = 120, .ohm = 817 }, 138 { .temp_c = 125, .ohm = 707 }, 139 }; 140 141 static const struct ntc_compensation ncpXXwf104[] = { 142 { .temp_c = -40, .ohm = 4397119 }, 143 { .temp_c = -35, .ohm = 3088599 }, 144 { .temp_c = -30, .ohm = 2197225 }, 145 { .temp_c = -25, .ohm = 1581881 }, 146 { .temp_c = -20, .ohm = 1151037 }, 147 { .temp_c = -15, .ohm = 846579 }, 148 { .temp_c = -10, .ohm = 628988 }, 149 { .temp_c = -5, .ohm = 471632 }, 150 { .temp_c = 0, .ohm = 357012 }, 151 { .temp_c = 5, .ohm = 272500 }, 152 { .temp_c = 10, .ohm = 209710 }, 153 { .temp_c = 15, .ohm = 162651 }, 154 { .temp_c = 20, .ohm = 127080 }, 155 { .temp_c = 25, .ohm = 100000 }, 156 { .temp_c = 30, .ohm = 79222 }, 157 { .temp_c = 35, .ohm = 63167 }, 158 { .temp_c = 40, .ohm = 50677 }, 159 { .temp_c = 45, .ohm = 40904 }, 160 { .temp_c = 50, .ohm = 33195 }, 161 { .temp_c = 55, .ohm = 27091 }, 162 { .temp_c = 60, .ohm = 22224 }, 163 { .temp_c = 65, .ohm = 18323 }, 164 { .temp_c = 70, .ohm = 15184 }, 165 { .temp_c = 75, .ohm = 12635 }, 166 { .temp_c = 80, .ohm = 10566 }, 167 { .temp_c = 85, .ohm = 8873 }, 168 { .temp_c = 90, .ohm = 7481 }, 169 { .temp_c = 95, .ohm = 6337 }, 170 { .temp_c = 100, .ohm = 5384 }, 171 { .temp_c = 105, .ohm = 4594 }, 172 { .temp_c = 110, .ohm = 3934 }, 173 { .temp_c = 115, .ohm = 3380 }, 174 { .temp_c = 120, .ohm = 2916 }, 175 { .temp_c = 125, .ohm = 2522 }, 176 }; 177 178 static const struct ntc_compensation ncpXXxh103[] = { 179 { .temp_c = -40, .ohm = 247565 }, 180 { .temp_c = -35, .ohm = 181742 }, 181 { .temp_c = -30, .ohm = 135128 }, 182 { .temp_c = -25, .ohm = 101678 }, 183 { .temp_c = -20, .ohm = 77373 }, 184 { .temp_c = -15, .ohm = 59504 }, 185 { .temp_c = -10, .ohm = 46222 }, 186 { .temp_c = -5, .ohm = 36244 }, 187 { .temp_c = 0, .ohm = 28674 }, 188 { .temp_c = 5, .ohm = 22878 }, 189 { .temp_c = 10, .ohm = 18399 }, 190 { .temp_c = 15, .ohm = 14910 }, 191 { .temp_c = 20, .ohm = 12169 }, 192 { .temp_c = 25, .ohm = 10000 }, 193 { .temp_c = 30, .ohm = 8271 }, 194 { .temp_c = 35, .ohm = 6883 }, 195 { .temp_c = 40, .ohm = 5762 }, 196 { .temp_c = 45, .ohm = 4851 }, 197 { .temp_c = 50, .ohm = 4105 }, 198 { .temp_c = 55, .ohm = 3492 }, 199 { .temp_c = 60, .ohm = 2985 }, 200 { .temp_c = 65, .ohm = 2563 }, 201 { .temp_c = 70, .ohm = 2211 }, 202 { .temp_c = 75, .ohm = 1915 }, 203 { .temp_c = 80, .ohm = 1666 }, 204 { .temp_c = 85, .ohm = 1454 }, 205 { .temp_c = 90, .ohm = 1275 }, 206 { .temp_c = 95, .ohm = 1121 }, 207 { .temp_c = 100, .ohm = 990 }, 208 { .temp_c = 105, .ohm = 876 }, 209 { .temp_c = 110, .ohm = 779 }, 210 { .temp_c = 115, .ohm = 694 }, 211 { .temp_c = 120, .ohm = 620 }, 212 { .temp_c = 125, .ohm = 556 }, 213 }; 214 215 /* 216 * The following compensation tables are from the specifications in EPCOS NTC 217 * Thermistors Datasheets 218 */ 219 static const struct ntc_compensation b57330v2103[] = { 220 { .temp_c = -40, .ohm = 190030 }, 221 { .temp_c = -35, .ohm = 145360 }, 222 { .temp_c = -30, .ohm = 112060 }, 223 { .temp_c = -25, .ohm = 87041 }, 224 { .temp_c = -20, .ohm = 68104 }, 225 { .temp_c = -15, .ohm = 53665 }, 226 { .temp_c = -10, .ohm = 42576 }, 227 { .temp_c = -5, .ohm = 34001 }, 228 { .temp_c = 0, .ohm = 27326 }, 229 { .temp_c = 5, .ohm = 22096 }, 230 { .temp_c = 10, .ohm = 17973 }, 231 { .temp_c = 15, .ohm = 14703 }, 232 { .temp_c = 20, .ohm = 12090 }, 233 { .temp_c = 25, .ohm = 10000 }, 234 { .temp_c = 30, .ohm = 8311 }, 235 { .temp_c = 35, .ohm = 6941 }, 236 { .temp_c = 40, .ohm = 5825 }, 237 { .temp_c = 45, .ohm = 4911 }, 238 { .temp_c = 50, .ohm = 4158 }, 239 { .temp_c = 55, .ohm = 3536 }, 240 { .temp_c = 60, .ohm = 3019 }, 241 { .temp_c = 65, .ohm = 2588 }, 242 { .temp_c = 70, .ohm = 2227 }, 243 { .temp_c = 75, .ohm = 1924 }, 244 { .temp_c = 80, .ohm = 1668 }, 245 { .temp_c = 85, .ohm = 1451 }, 246 { .temp_c = 90, .ohm = 1266 }, 247 { .temp_c = 95, .ohm = 1108 }, 248 { .temp_c = 100, .ohm = 973 }, 249 { .temp_c = 105, .ohm = 857 }, 250 { .temp_c = 110, .ohm = 757 }, 251 { .temp_c = 115, .ohm = 671 }, 252 { .temp_c = 120, .ohm = 596 }, 253 { .temp_c = 125, .ohm = 531 }, 254 }; 255 256 static const struct ntc_compensation b57891s0103[] = { 257 { .temp_c = -55.0, .ohm = 878900 }, 258 { .temp_c = -50.0, .ohm = 617590 }, 259 { .temp_c = -45.0, .ohm = 439340 }, 260 { .temp_c = -40.0, .ohm = 316180 }, 261 { .temp_c = -35.0, .ohm = 230060 }, 262 { .temp_c = -30.0, .ohm = 169150 }, 263 { .temp_c = -25.0, .ohm = 125550 }, 264 { .temp_c = -20.0, .ohm = 94143 }, 265 { .temp_c = -15.0, .ohm = 71172 }, 266 { .temp_c = -10.0, .ohm = 54308 }, 267 { .temp_c = -5.0, .ohm = 41505 }, 268 { .temp_c = 0.0, .ohm = 32014 }, 269 { .temp_c = 5.0, .ohm = 25011 }, 270 { .temp_c = 10.0, .ohm = 19691 }, 271 { .temp_c = 15.0, .ohm = 15618 }, 272 { .temp_c = 20.0, .ohm = 12474 }, 273 { .temp_c = 25.0, .ohm = 10000 }, 274 { .temp_c = 30.0, .ohm = 8080 }, 275 { .temp_c = 35.0, .ohm = 6569 }, 276 { .temp_c = 40.0, .ohm = 5372 }, 277 { .temp_c = 45.0, .ohm = 4424 }, 278 { .temp_c = 50.0, .ohm = 3661 }, 279 { .temp_c = 55.0, .ohm = 3039 }, 280 { .temp_c = 60.0, .ohm = 2536 }, 281 { .temp_c = 65.0, .ohm = 2128 }, 282 { .temp_c = 70.0, .ohm = 1794 }, 283 { .temp_c = 75.0, .ohm = 1518 }, 284 { .temp_c = 80.0, .ohm = 1290 }, 285 { .temp_c = 85.0, .ohm = 1100 }, 286 { .temp_c = 90.0, .ohm = 942 }, 287 { .temp_c = 95.0, .ohm = 809 }, 288 { .temp_c = 100.0, .ohm = 697 }, 289 { .temp_c = 105.0, .ohm = 604 }, 290 { .temp_c = 110.0, .ohm = 525 }, 291 { .temp_c = 115.0, .ohm = 457 }, 292 { .temp_c = 120.0, .ohm = 400 }, 293 { .temp_c = 125.0, .ohm = 351 }, 294 { .temp_c = 130.0, .ohm = 308 }, 295 { .temp_c = 135.0, .ohm = 272 }, 296 { .temp_c = 140.0, .ohm = 240 }, 297 { .temp_c = 145.0, .ohm = 213 }, 298 { .temp_c = 150.0, .ohm = 189 }, 299 { .temp_c = 155.0, .ohm = 168 }, 300 }; 301 302 struct ntc_type { 303 const struct ntc_compensation *comp; 304 int n_comp; 305 }; 306 307 #define NTC_TYPE(ntc, compensation) \ 308 [(ntc)] = { .comp = (compensation), .n_comp = ARRAY_SIZE(compensation) } 309 310 static const struct ntc_type ntc_type[] = { 311 NTC_TYPE(TYPE_B57330V2103, b57330v2103), 312 NTC_TYPE(TYPE_B57891S0103, b57891s0103), 313 NTC_TYPE(TYPE_NCPXXWB473, ncpXXwb473), 314 NTC_TYPE(TYPE_NCPXXWF104, ncpXXwf104), 315 NTC_TYPE(TYPE_NCPXXWL333, ncpXXwl333), 316 NTC_TYPE(TYPE_NCPXXXH103, ncpXXxh103), 317 }; 318 319 struct ntc_data { 320 struct ntc_thermistor_platform_data *pdata; 321 const struct ntc_compensation *comp; 322 int n_comp; 323 }; 324 325 #if defined(CONFIG_OF) && IS_ENABLED(CONFIG_IIO) 326 static int ntc_adc_iio_read(struct ntc_thermistor_platform_data *pdata) 327 { 328 struct iio_channel *channel = pdata->chan; 329 int raw, uv, ret; 330 331 ret = iio_read_channel_raw(channel, &raw); 332 if (ret < 0) { 333 pr_err("read channel() error: %d\n", ret); 334 return ret; 335 } 336 337 ret = iio_convert_raw_to_processed(channel, raw, &uv, 1000); 338 if (ret < 0) { 339 /* Assume 12 bit ADC with vref at pullup_uv */ 340 uv = (pdata->pullup_uv * (s64)raw) >> 12; 341 } 342 343 return uv; 344 } 345 346 static const struct of_device_id ntc_match[] = { 347 { .compatible = "epcos,b57330v2103", 348 .data = &ntc_thermistor_id[NTC_B57330V2103]}, 349 { .compatible = "epcos,b57891s0103", 350 .data = &ntc_thermistor_id[NTC_B57891S0103] }, 351 { .compatible = "murata,ncp03wb473", 352 .data = &ntc_thermistor_id[NTC_NCP03WB473] }, 353 { .compatible = "murata,ncp03wf104", 354 .data = &ntc_thermistor_id[NTC_NCP03WF104] }, 355 { .compatible = "murata,ncp15wb473", 356 .data = &ntc_thermistor_id[NTC_NCP15WB473] }, 357 { .compatible = "murata,ncp15wl333", 358 .data = &ntc_thermistor_id[NTC_NCP15WL333] }, 359 { .compatible = "murata,ncp15xh103", 360 .data = &ntc_thermistor_id[NTC_NCP15XH103] }, 361 { .compatible = "murata,ncp18wb473", 362 .data = &ntc_thermistor_id[NTC_NCP18WB473] }, 363 { .compatible = "murata,ncp21wb473", 364 .data = &ntc_thermistor_id[NTC_NCP21WB473] }, 365 366 /* Usage of vendor name "ntc" is deprecated */ 367 { .compatible = "ntc,ncp03wb473", 368 .data = &ntc_thermistor_id[NTC_NCP03WB473] }, 369 { .compatible = "ntc,ncp15wb473", 370 .data = &ntc_thermistor_id[NTC_NCP15WB473] }, 371 { .compatible = "ntc,ncp15wl333", 372 .data = &ntc_thermistor_id[NTC_NCP15WL333] }, 373 { .compatible = "ntc,ncp18wb473", 374 .data = &ntc_thermistor_id[NTC_NCP18WB473] }, 375 { .compatible = "ntc,ncp21wb473", 376 .data = &ntc_thermistor_id[NTC_NCP21WB473] }, 377 { }, 378 }; 379 MODULE_DEVICE_TABLE(of, ntc_match); 380 381 static struct ntc_thermistor_platform_data * 382 ntc_thermistor_parse_dt(struct device *dev) 383 { 384 struct iio_channel *chan; 385 enum iio_chan_type type; 386 struct device_node *np = dev->of_node; 387 struct ntc_thermistor_platform_data *pdata; 388 int ret; 389 390 if (!np) 391 return NULL; 392 393 pdata = devm_kzalloc(dev, sizeof(*pdata), GFP_KERNEL); 394 if (!pdata) 395 return ERR_PTR(-ENOMEM); 396 397 chan = devm_iio_channel_get(dev, NULL); 398 if (IS_ERR(chan)) 399 return ERR_CAST(chan); 400 401 ret = iio_get_channel_type(chan, &type); 402 if (ret < 0) 403 return ERR_PTR(ret); 404 405 if (type != IIO_VOLTAGE) 406 return ERR_PTR(-EINVAL); 407 408 if (of_property_read_u32(np, "pullup-uv", &pdata->pullup_uv)) 409 return ERR_PTR(-ENODEV); 410 if (of_property_read_u32(np, "pullup-ohm", &pdata->pullup_ohm)) 411 return ERR_PTR(-ENODEV); 412 if (of_property_read_u32(np, "pulldown-ohm", &pdata->pulldown_ohm)) 413 return ERR_PTR(-ENODEV); 414 415 if (of_find_property(np, "connected-positive", NULL)) 416 pdata->connect = NTC_CONNECTED_POSITIVE; 417 else /* status change should be possible if not always on. */ 418 pdata->connect = NTC_CONNECTED_GROUND; 419 420 pdata->chan = chan; 421 pdata->read_uv = ntc_adc_iio_read; 422 423 return pdata; 424 } 425 #else 426 static struct ntc_thermistor_platform_data * 427 ntc_thermistor_parse_dt(struct device *dev) 428 { 429 return NULL; 430 } 431 432 #define ntc_match NULL 433 434 #endif 435 436 static inline u64 div64_u64_safe(u64 dividend, u64 divisor) 437 { 438 if (divisor == 0 && dividend == 0) 439 return 0; 440 if (divisor == 0) 441 return UINT_MAX; 442 return div64_u64(dividend, divisor); 443 } 444 445 static int get_ohm_of_thermistor(struct ntc_data *data, unsigned int uv) 446 { 447 struct ntc_thermistor_platform_data *pdata = data->pdata; 448 u32 puv = pdata->pullup_uv; 449 u64 n, puo, pdo; 450 puo = pdata->pullup_ohm; 451 pdo = pdata->pulldown_ohm; 452 453 if (uv == 0) 454 return (pdata->connect == NTC_CONNECTED_POSITIVE) ? 455 INT_MAX : 0; 456 if (uv >= puv) 457 return (pdata->connect == NTC_CONNECTED_POSITIVE) ? 458 0 : INT_MAX; 459 460 if (pdata->connect == NTC_CONNECTED_POSITIVE && puo == 0) 461 n = div_u64(pdo * (puv - uv), uv); 462 else if (pdata->connect == NTC_CONNECTED_GROUND && pdo == 0) 463 n = div_u64(puo * uv, puv - uv); 464 else if (pdata->connect == NTC_CONNECTED_POSITIVE) 465 n = div64_u64_safe(pdo * puo * (puv - uv), 466 puo * uv - pdo * (puv - uv)); 467 else 468 n = div64_u64_safe(pdo * puo * uv, pdo * (puv - uv) - puo * uv); 469 470 if (n > INT_MAX) 471 n = INT_MAX; 472 return n; 473 } 474 475 static void lookup_comp(struct ntc_data *data, unsigned int ohm, 476 int *i_low, int *i_high) 477 { 478 int start, end, mid; 479 480 /* 481 * Handle special cases: Resistance is higher than or equal to 482 * resistance in first table entry, or resistance is lower or equal 483 * to resistance in last table entry. 484 * In these cases, return i_low == i_high, either pointing to the 485 * beginning or to the end of the table depending on the condition. 486 */ 487 if (ohm >= data->comp[0].ohm) { 488 *i_low = 0; 489 *i_high = 0; 490 return; 491 } 492 if (ohm <= data->comp[data->n_comp - 1].ohm) { 493 *i_low = data->n_comp - 1; 494 *i_high = data->n_comp - 1; 495 return; 496 } 497 498 /* Do a binary search on compensation table */ 499 start = 0; 500 end = data->n_comp; 501 while (start < end) { 502 mid = start + (end - start) / 2; 503 /* 504 * start <= mid < end 505 * data->comp[start].ohm > ohm >= data->comp[end].ohm 506 * 507 * We could check for "ohm == data->comp[mid].ohm" here, but 508 * that is a quite unlikely condition, and we would have to 509 * check again after updating start. Check it at the end instead 510 * for simplicity. 511 */ 512 if (ohm >= data->comp[mid].ohm) { 513 end = mid; 514 } else { 515 start = mid + 1; 516 /* 517 * ohm >= data->comp[start].ohm might be true here, 518 * since we set start to mid + 1. In that case, we are 519 * done. We could keep going, but the condition is quite 520 * likely to occur, so it is worth checking for it. 521 */ 522 if (ohm >= data->comp[start].ohm) 523 end = start; 524 } 525 /* 526 * start <= end 527 * data->comp[start].ohm >= ohm >= data->comp[end].ohm 528 */ 529 } 530 /* 531 * start == end 532 * ohm >= data->comp[end].ohm 533 */ 534 *i_low = end; 535 if (ohm == data->comp[end].ohm) 536 *i_high = end; 537 else 538 *i_high = end - 1; 539 } 540 541 static int get_temp_mc(struct ntc_data *data, unsigned int ohm) 542 { 543 int low, high; 544 int temp; 545 546 lookup_comp(data, ohm, &low, &high); 547 if (low == high) { 548 /* Unable to use linear approximation */ 549 temp = data->comp[low].temp_c * 1000; 550 } else { 551 temp = data->comp[low].temp_c * 1000 + 552 ((data->comp[high].temp_c - data->comp[low].temp_c) * 553 1000 * ((int)ohm - (int)data->comp[low].ohm)) / 554 ((int)data->comp[high].ohm - (int)data->comp[low].ohm); 555 } 556 return temp; 557 } 558 559 static int ntc_thermistor_get_ohm(struct ntc_data *data) 560 { 561 int read_uv; 562 563 if (data->pdata->read_ohm) 564 return data->pdata->read_ohm(); 565 566 if (data->pdata->read_uv) { 567 read_uv = data->pdata->read_uv(data->pdata); 568 if (read_uv < 0) 569 return read_uv; 570 return get_ohm_of_thermistor(data, read_uv); 571 } 572 return -EINVAL; 573 } 574 575 static int ntc_read(struct device *dev, enum hwmon_sensor_types type, 576 u32 attr, int channel, long *val) 577 { 578 struct ntc_data *data = dev_get_drvdata(dev); 579 int ohm; 580 581 switch (type) { 582 case hwmon_temp: 583 switch (attr) { 584 case hwmon_temp_input: 585 ohm = ntc_thermistor_get_ohm(data); 586 if (ohm < 0) 587 return ohm; 588 *val = get_temp_mc(data, ohm); 589 return 0; 590 case hwmon_temp_type: 591 *val = 4; 592 return 0; 593 default: 594 break; 595 } 596 break; 597 default: 598 break; 599 } 600 return -EINVAL; 601 } 602 603 static umode_t ntc_is_visible(const void *data, enum hwmon_sensor_types type, 604 u32 attr, int channel) 605 { 606 if (type == hwmon_temp) { 607 switch (attr) { 608 case hwmon_temp_input: 609 case hwmon_temp_type: 610 return 0444; 611 default: 612 break; 613 } 614 } 615 return 0; 616 } 617 618 static const struct hwmon_channel_info *ntc_info[] = { 619 HWMON_CHANNEL_INFO(chip, HWMON_C_REGISTER_TZ), 620 HWMON_CHANNEL_INFO(temp, HWMON_T_INPUT | HWMON_T_TYPE), 621 NULL 622 }; 623 624 static const struct hwmon_ops ntc_hwmon_ops = { 625 .is_visible = ntc_is_visible, 626 .read = ntc_read, 627 }; 628 629 static const struct hwmon_chip_info ntc_chip_info = { 630 .ops = &ntc_hwmon_ops, 631 .info = ntc_info, 632 }; 633 634 static int ntc_thermistor_probe(struct platform_device *pdev) 635 { 636 struct device *dev = &pdev->dev; 637 const struct of_device_id *of_id = 638 of_match_device(of_match_ptr(ntc_match), dev); 639 const struct platform_device_id *pdev_id; 640 struct ntc_thermistor_platform_data *pdata; 641 struct device *hwmon_dev; 642 struct ntc_data *data; 643 644 pdata = ntc_thermistor_parse_dt(dev); 645 if (IS_ERR(pdata)) 646 return PTR_ERR(pdata); 647 else if (pdata == NULL) 648 pdata = dev_get_platdata(dev); 649 650 if (!pdata) { 651 dev_err(dev, "No platform init data supplied.\n"); 652 return -ENODEV; 653 } 654 655 /* Either one of the two is required. */ 656 if (!pdata->read_uv && !pdata->read_ohm) { 657 dev_err(dev, 658 "Both read_uv and read_ohm missing. Need either one of the two.\n"); 659 return -EINVAL; 660 } 661 662 if (pdata->read_uv && pdata->read_ohm) { 663 dev_warn(dev, 664 "Only one of read_uv and read_ohm is needed; ignoring read_uv.\n"); 665 pdata->read_uv = NULL; 666 } 667 668 if (pdata->read_uv && (pdata->pullup_uv == 0 || 669 (pdata->pullup_ohm == 0 && pdata->connect == 670 NTC_CONNECTED_GROUND) || 671 (pdata->pulldown_ohm == 0 && pdata->connect == 672 NTC_CONNECTED_POSITIVE) || 673 (pdata->connect != NTC_CONNECTED_POSITIVE && 674 pdata->connect != NTC_CONNECTED_GROUND))) { 675 dev_err(dev, "Required data to use read_uv not supplied.\n"); 676 return -EINVAL; 677 } 678 679 data = devm_kzalloc(dev, sizeof(struct ntc_data), GFP_KERNEL); 680 if (!data) 681 return -ENOMEM; 682 683 pdev_id = of_id ? of_id->data : platform_get_device_id(pdev); 684 685 data->pdata = pdata; 686 687 if (pdev_id->driver_data >= ARRAY_SIZE(ntc_type)) { 688 dev_err(dev, "Unknown device type: %lu(%s)\n", 689 pdev_id->driver_data, pdev_id->name); 690 return -EINVAL; 691 } 692 693 data->comp = ntc_type[pdev_id->driver_data].comp; 694 data->n_comp = ntc_type[pdev_id->driver_data].n_comp; 695 696 hwmon_dev = devm_hwmon_device_register_with_info(dev, pdev_id->name, 697 data, &ntc_chip_info, 698 NULL); 699 if (IS_ERR(hwmon_dev)) { 700 dev_err(dev, "unable to register as hwmon device.\n"); 701 return PTR_ERR(hwmon_dev); 702 } 703 704 dev_info(dev, "Thermistor type: %s successfully probed.\n", 705 pdev_id->name); 706 707 return 0; 708 } 709 710 static struct platform_driver ntc_thermistor_driver = { 711 .driver = { 712 .name = "ntc-thermistor", 713 .of_match_table = of_match_ptr(ntc_match), 714 }, 715 .probe = ntc_thermistor_probe, 716 .id_table = ntc_thermistor_id, 717 }; 718 719 module_platform_driver(ntc_thermistor_driver); 720 721 MODULE_DESCRIPTION("NTC Thermistor Driver"); 722 MODULE_AUTHOR("MyungJoo Ham <myungjoo.ham@samsung.com>"); 723 MODULE_LICENSE("GPL"); 724 MODULE_ALIAS("platform:ntc-thermistor"); 725