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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
27struct 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 */
36enum {
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
49static 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 */
68static 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};
104static 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
141static 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
178static 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 */
219static 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
256static 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
302struct 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
310static 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
319struct 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)
326static 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
346static 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};
379MODULE_DEVICE_TABLE(of, ntc_match);
380
381static struct ntc_thermistor_platform_data *
382ntc_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
426static struct ntc_thermistor_platform_data *
427ntc_thermistor_parse_dt(struct device *dev)
428{
429 return NULL;
430}
431
432#define ntc_match NULL
433
434#endif
435
436static 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
445static 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
475static 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
541static 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
559static 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
575static 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
603static 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
618static 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
624static const struct hwmon_ops ntc_hwmon_ops = {
625 .is_visible = ntc_is_visible,
626 .read = ntc_read,
627};
628
629static const struct hwmon_chip_info ntc_chip_info = {
630 .ops = &ntc_hwmon_ops,
631 .info = ntc_info,
632};
633
634static 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
710static 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
719module_platform_driver(ntc_thermistor_driver);
720
721MODULE_DESCRIPTION("NTC Thermistor Driver");
722MODULE_AUTHOR("MyungJoo Ham <myungjoo.ham@samsung.com>");
723MODULE_LICENSE("GPL");
724MODULE_ALIAS("platform:ntc-thermistor");
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/err.h>
14#include <linux/of.h>
15#include <linux/of_device.h>
16
17#include <linux/platform_data/ntc_thermistor.h>
18
19#include <linux/iio/consumer.h>
20
21#include <linux/hwmon.h>
22
23struct ntc_compensation {
24 int temp_c;
25 unsigned int ohm;
26};
27
28/*
29 * Used as index in a zero-terminated array, holes not allowed so
30 * that NTC_LAST is the first empty array entry.
31 */
32enum {
33 NTC_B57330V2103,
34 NTC_B57891S0103,
35 NTC_NCP03WB473,
36 NTC_NCP03WF104,
37 NTC_NCP15WB473,
38 NTC_NCP15WL333,
39 NTC_NCP15XH103,
40 NTC_NCP18WB473,
41 NTC_NCP21WB473,
42 NTC_LAST,
43};
44
45static const struct platform_device_id ntc_thermistor_id[] = {
46 [NTC_B57330V2103] = { "b57330v2103", TYPE_B57330V2103 },
47 [NTC_B57891S0103] = { "b57891s0103", TYPE_B57891S0103 },
48 [NTC_NCP03WB473] = { "ncp03wb473", TYPE_NCPXXWB473 },
49 [NTC_NCP03WF104] = { "ncp03wf104", TYPE_NCPXXWF104 },
50 [NTC_NCP15WB473] = { "ncp15wb473", TYPE_NCPXXWB473 },
51 [NTC_NCP15WL333] = { "ncp15wl333", TYPE_NCPXXWL333 },
52 [NTC_NCP15XH103] = { "ncp15xh103", TYPE_NCPXXXH103 },
53 [NTC_NCP18WB473] = { "ncp18wb473", TYPE_NCPXXWB473 },
54 [NTC_NCP21WB473] = { "ncp21wb473", TYPE_NCPXXWB473 },
55 [NTC_LAST] = { },
56};
57
58/*
59 * A compensation table should be sorted by the values of .ohm
60 * in descending order.
61 * The following compensation tables are from the specification of Murata NTC
62 * Thermistors Datasheet
63 */
64static const struct ntc_compensation ncpXXwb473[] = {
65 { .temp_c = -40, .ohm = 1747920 },
66 { .temp_c = -35, .ohm = 1245428 },
67 { .temp_c = -30, .ohm = 898485 },
68 { .temp_c = -25, .ohm = 655802 },
69 { .temp_c = -20, .ohm = 483954 },
70 { .temp_c = -15, .ohm = 360850 },
71 { .temp_c = -10, .ohm = 271697 },
72 { .temp_c = -5, .ohm = 206463 },
73 { .temp_c = 0, .ohm = 158214 },
74 { .temp_c = 5, .ohm = 122259 },
75 { .temp_c = 10, .ohm = 95227 },
76 { .temp_c = 15, .ohm = 74730 },
77 { .temp_c = 20, .ohm = 59065 },
78 { .temp_c = 25, .ohm = 47000 },
79 { .temp_c = 30, .ohm = 37643 },
80 { .temp_c = 35, .ohm = 30334 },
81 { .temp_c = 40, .ohm = 24591 },
82 { .temp_c = 45, .ohm = 20048 },
83 { .temp_c = 50, .ohm = 16433 },
84 { .temp_c = 55, .ohm = 13539 },
85 { .temp_c = 60, .ohm = 11209 },
86 { .temp_c = 65, .ohm = 9328 },
87 { .temp_c = 70, .ohm = 7798 },
88 { .temp_c = 75, .ohm = 6544 },
89 { .temp_c = 80, .ohm = 5518 },
90 { .temp_c = 85, .ohm = 4674 },
91 { .temp_c = 90, .ohm = 3972 },
92 { .temp_c = 95, .ohm = 3388 },
93 { .temp_c = 100, .ohm = 2902 },
94 { .temp_c = 105, .ohm = 2494 },
95 { .temp_c = 110, .ohm = 2150 },
96 { .temp_c = 115, .ohm = 1860 },
97 { .temp_c = 120, .ohm = 1615 },
98 { .temp_c = 125, .ohm = 1406 },
99};
100static const struct ntc_compensation ncpXXwl333[] = {
101 { .temp_c = -40, .ohm = 1610154 },
102 { .temp_c = -35, .ohm = 1130850 },
103 { .temp_c = -30, .ohm = 802609 },
104 { .temp_c = -25, .ohm = 575385 },
105 { .temp_c = -20, .ohm = 416464 },
106 { .temp_c = -15, .ohm = 304219 },
107 { .temp_c = -10, .ohm = 224193 },
108 { .temp_c = -5, .ohm = 166623 },
109 { .temp_c = 0, .ohm = 124850 },
110 { .temp_c = 5, .ohm = 94287 },
111 { .temp_c = 10, .ohm = 71747 },
112 { .temp_c = 15, .ohm = 54996 },
113 { .temp_c = 20, .ohm = 42455 },
114 { .temp_c = 25, .ohm = 33000 },
115 { .temp_c = 30, .ohm = 25822 },
116 { .temp_c = 35, .ohm = 20335 },
117 { .temp_c = 40, .ohm = 16115 },
118 { .temp_c = 45, .ohm = 12849 },
119 { .temp_c = 50, .ohm = 10306 },
120 { .temp_c = 55, .ohm = 8314 },
121 { .temp_c = 60, .ohm = 6746 },
122 { .temp_c = 65, .ohm = 5503 },
123 { .temp_c = 70, .ohm = 4513 },
124 { .temp_c = 75, .ohm = 3721 },
125 { .temp_c = 80, .ohm = 3084 },
126 { .temp_c = 85, .ohm = 2569 },
127 { .temp_c = 90, .ohm = 2151 },
128 { .temp_c = 95, .ohm = 1809 },
129 { .temp_c = 100, .ohm = 1529 },
130 { .temp_c = 105, .ohm = 1299 },
131 { .temp_c = 110, .ohm = 1108 },
132 { .temp_c = 115, .ohm = 949 },
133 { .temp_c = 120, .ohm = 817 },
134 { .temp_c = 125, .ohm = 707 },
135};
136
137static const struct ntc_compensation ncpXXwf104[] = {
138 { .temp_c = -40, .ohm = 4397119 },
139 { .temp_c = -35, .ohm = 3088599 },
140 { .temp_c = -30, .ohm = 2197225 },
141 { .temp_c = -25, .ohm = 1581881 },
142 { .temp_c = -20, .ohm = 1151037 },
143 { .temp_c = -15, .ohm = 846579 },
144 { .temp_c = -10, .ohm = 628988 },
145 { .temp_c = -5, .ohm = 471632 },
146 { .temp_c = 0, .ohm = 357012 },
147 { .temp_c = 5, .ohm = 272500 },
148 { .temp_c = 10, .ohm = 209710 },
149 { .temp_c = 15, .ohm = 162651 },
150 { .temp_c = 20, .ohm = 127080 },
151 { .temp_c = 25, .ohm = 100000 },
152 { .temp_c = 30, .ohm = 79222 },
153 { .temp_c = 35, .ohm = 63167 },
154 { .temp_c = 40, .ohm = 50677 },
155 { .temp_c = 45, .ohm = 40904 },
156 { .temp_c = 50, .ohm = 33195 },
157 { .temp_c = 55, .ohm = 27091 },
158 { .temp_c = 60, .ohm = 22224 },
159 { .temp_c = 65, .ohm = 18323 },
160 { .temp_c = 70, .ohm = 15184 },
161 { .temp_c = 75, .ohm = 12635 },
162 { .temp_c = 80, .ohm = 10566 },
163 { .temp_c = 85, .ohm = 8873 },
164 { .temp_c = 90, .ohm = 7481 },
165 { .temp_c = 95, .ohm = 6337 },
166 { .temp_c = 100, .ohm = 5384 },
167 { .temp_c = 105, .ohm = 4594 },
168 { .temp_c = 110, .ohm = 3934 },
169 { .temp_c = 115, .ohm = 3380 },
170 { .temp_c = 120, .ohm = 2916 },
171 { .temp_c = 125, .ohm = 2522 },
172};
173
174static const struct ntc_compensation ncpXXxh103[] = {
175 { .temp_c = -40, .ohm = 247565 },
176 { .temp_c = -35, .ohm = 181742 },
177 { .temp_c = -30, .ohm = 135128 },
178 { .temp_c = -25, .ohm = 101678 },
179 { .temp_c = -20, .ohm = 77373 },
180 { .temp_c = -15, .ohm = 59504 },
181 { .temp_c = -10, .ohm = 46222 },
182 { .temp_c = -5, .ohm = 36244 },
183 { .temp_c = 0, .ohm = 28674 },
184 { .temp_c = 5, .ohm = 22878 },
185 { .temp_c = 10, .ohm = 18399 },
186 { .temp_c = 15, .ohm = 14910 },
187 { .temp_c = 20, .ohm = 12169 },
188 { .temp_c = 25, .ohm = 10000 },
189 { .temp_c = 30, .ohm = 8271 },
190 { .temp_c = 35, .ohm = 6883 },
191 { .temp_c = 40, .ohm = 5762 },
192 { .temp_c = 45, .ohm = 4851 },
193 { .temp_c = 50, .ohm = 4105 },
194 { .temp_c = 55, .ohm = 3492 },
195 { .temp_c = 60, .ohm = 2985 },
196 { .temp_c = 65, .ohm = 2563 },
197 { .temp_c = 70, .ohm = 2211 },
198 { .temp_c = 75, .ohm = 1915 },
199 { .temp_c = 80, .ohm = 1666 },
200 { .temp_c = 85, .ohm = 1454 },
201 { .temp_c = 90, .ohm = 1275 },
202 { .temp_c = 95, .ohm = 1121 },
203 { .temp_c = 100, .ohm = 990 },
204 { .temp_c = 105, .ohm = 876 },
205 { .temp_c = 110, .ohm = 779 },
206 { .temp_c = 115, .ohm = 694 },
207 { .temp_c = 120, .ohm = 620 },
208 { .temp_c = 125, .ohm = 556 },
209};
210
211/*
212 * The following compensation tables are from the specifications in EPCOS NTC
213 * Thermistors Datasheets
214 */
215static const struct ntc_compensation b57330v2103[] = {
216 { .temp_c = -40, .ohm = 190030 },
217 { .temp_c = -35, .ohm = 145360 },
218 { .temp_c = -30, .ohm = 112060 },
219 { .temp_c = -25, .ohm = 87041 },
220 { .temp_c = -20, .ohm = 68104 },
221 { .temp_c = -15, .ohm = 53665 },
222 { .temp_c = -10, .ohm = 42576 },
223 { .temp_c = -5, .ohm = 34001 },
224 { .temp_c = 0, .ohm = 27326 },
225 { .temp_c = 5, .ohm = 22096 },
226 { .temp_c = 10, .ohm = 17973 },
227 { .temp_c = 15, .ohm = 14703 },
228 { .temp_c = 20, .ohm = 12090 },
229 { .temp_c = 25, .ohm = 10000 },
230 { .temp_c = 30, .ohm = 8311 },
231 { .temp_c = 35, .ohm = 6941 },
232 { .temp_c = 40, .ohm = 5825 },
233 { .temp_c = 45, .ohm = 4911 },
234 { .temp_c = 50, .ohm = 4158 },
235 { .temp_c = 55, .ohm = 3536 },
236 { .temp_c = 60, .ohm = 3019 },
237 { .temp_c = 65, .ohm = 2588 },
238 { .temp_c = 70, .ohm = 2227 },
239 { .temp_c = 75, .ohm = 1924 },
240 { .temp_c = 80, .ohm = 1668 },
241 { .temp_c = 85, .ohm = 1451 },
242 { .temp_c = 90, .ohm = 1266 },
243 { .temp_c = 95, .ohm = 1108 },
244 { .temp_c = 100, .ohm = 973 },
245 { .temp_c = 105, .ohm = 857 },
246 { .temp_c = 110, .ohm = 757 },
247 { .temp_c = 115, .ohm = 671 },
248 { .temp_c = 120, .ohm = 596 },
249 { .temp_c = 125, .ohm = 531 },
250};
251
252static const struct ntc_compensation b57891s0103[] = {
253 { .temp_c = -55.0, .ohm = 878900 },
254 { .temp_c = -50.0, .ohm = 617590 },
255 { .temp_c = -45.0, .ohm = 439340 },
256 { .temp_c = -40.0, .ohm = 316180 },
257 { .temp_c = -35.0, .ohm = 230060 },
258 { .temp_c = -30.0, .ohm = 169150 },
259 { .temp_c = -25.0, .ohm = 125550 },
260 { .temp_c = -20.0, .ohm = 94143 },
261 { .temp_c = -15.0, .ohm = 71172 },
262 { .temp_c = -10.0, .ohm = 54308 },
263 { .temp_c = -5.0, .ohm = 41505 },
264 { .temp_c = 0.0, .ohm = 32014 },
265 { .temp_c = 5.0, .ohm = 25011 },
266 { .temp_c = 10.0, .ohm = 19691 },
267 { .temp_c = 15.0, .ohm = 15618 },
268 { .temp_c = 20.0, .ohm = 12474 },
269 { .temp_c = 25.0, .ohm = 10000 },
270 { .temp_c = 30.0, .ohm = 8080 },
271 { .temp_c = 35.0, .ohm = 6569 },
272 { .temp_c = 40.0, .ohm = 5372 },
273 { .temp_c = 45.0, .ohm = 4424 },
274 { .temp_c = 50.0, .ohm = 3661 },
275 { .temp_c = 55.0, .ohm = 3039 },
276 { .temp_c = 60.0, .ohm = 2536 },
277 { .temp_c = 65.0, .ohm = 2128 },
278 { .temp_c = 70.0, .ohm = 1794 },
279 { .temp_c = 75.0, .ohm = 1518 },
280 { .temp_c = 80.0, .ohm = 1290 },
281 { .temp_c = 85.0, .ohm = 1100 },
282 { .temp_c = 90.0, .ohm = 942 },
283 { .temp_c = 95.0, .ohm = 809 },
284 { .temp_c = 100.0, .ohm = 697 },
285 { .temp_c = 105.0, .ohm = 604 },
286 { .temp_c = 110.0, .ohm = 525 },
287 { .temp_c = 115.0, .ohm = 457 },
288 { .temp_c = 120.0, .ohm = 400 },
289 { .temp_c = 125.0, .ohm = 351 },
290 { .temp_c = 130.0, .ohm = 308 },
291 { .temp_c = 135.0, .ohm = 272 },
292 { .temp_c = 140.0, .ohm = 240 },
293 { .temp_c = 145.0, .ohm = 213 },
294 { .temp_c = 150.0, .ohm = 189 },
295 { .temp_c = 155.0, .ohm = 168 },
296};
297
298struct ntc_type {
299 const struct ntc_compensation *comp;
300 int n_comp;
301};
302
303#define NTC_TYPE(ntc, compensation) \
304[(ntc)] = { .comp = (compensation), .n_comp = ARRAY_SIZE(compensation) }
305
306static const struct ntc_type ntc_type[] = {
307 NTC_TYPE(TYPE_B57330V2103, b57330v2103),
308 NTC_TYPE(TYPE_B57891S0103, b57891s0103),
309 NTC_TYPE(TYPE_NCPXXWB473, ncpXXwb473),
310 NTC_TYPE(TYPE_NCPXXWF104, ncpXXwf104),
311 NTC_TYPE(TYPE_NCPXXWL333, ncpXXwl333),
312 NTC_TYPE(TYPE_NCPXXXH103, ncpXXxh103),
313};
314
315struct ntc_data {
316 struct ntc_thermistor_platform_data *pdata;
317 const struct ntc_compensation *comp;
318 int n_comp;
319};
320
321#if defined(CONFIG_OF) && IS_ENABLED(CONFIG_IIO)
322static int ntc_adc_iio_read(struct ntc_thermistor_platform_data *pdata)
323{
324 struct iio_channel *channel = pdata->chan;
325 int uv, ret;
326
327 ret = iio_read_channel_processed_scale(channel, &uv, 1000);
328 if (ret < 0) {
329 int raw;
330
331 /*
332 * This fallback uses a raw read and then
333 * assumes the ADC is 12 bits, scaling with
334 * a factor 1000 to get to microvolts.
335 */
336 ret = iio_read_channel_raw(channel, &raw);
337 if (ret < 0) {
338 pr_err("read channel() error: %d\n", ret);
339 return ret;
340 }
341 ret = iio_convert_raw_to_processed(channel, raw, &uv, 1000);
342 if (ret < 0) {
343 /* Assume 12 bit ADC with vref at pullup_uv */
344 uv = (pdata->pullup_uv * (s64)raw) >> 12;
345 }
346 }
347
348 return uv;
349}
350
351static const struct of_device_id ntc_match[] = {
352 { .compatible = "epcos,b57330v2103",
353 .data = &ntc_thermistor_id[NTC_B57330V2103]},
354 { .compatible = "epcos,b57891s0103",
355 .data = &ntc_thermistor_id[NTC_B57891S0103] },
356 { .compatible = "murata,ncp03wb473",
357 .data = &ntc_thermistor_id[NTC_NCP03WB473] },
358 { .compatible = "murata,ncp03wf104",
359 .data = &ntc_thermistor_id[NTC_NCP03WF104] },
360 { .compatible = "murata,ncp15wb473",
361 .data = &ntc_thermistor_id[NTC_NCP15WB473] },
362 { .compatible = "murata,ncp15wl333",
363 .data = &ntc_thermistor_id[NTC_NCP15WL333] },
364 { .compatible = "murata,ncp15xh103",
365 .data = &ntc_thermistor_id[NTC_NCP15XH103] },
366 { .compatible = "murata,ncp18wb473",
367 .data = &ntc_thermistor_id[NTC_NCP18WB473] },
368 { .compatible = "murata,ncp21wb473",
369 .data = &ntc_thermistor_id[NTC_NCP21WB473] },
370
371 /* Usage of vendor name "ntc" is deprecated */
372 { .compatible = "ntc,ncp03wb473",
373 .data = &ntc_thermistor_id[NTC_NCP03WB473] },
374 { .compatible = "ntc,ncp15wb473",
375 .data = &ntc_thermistor_id[NTC_NCP15WB473] },
376 { .compatible = "ntc,ncp15wl333",
377 .data = &ntc_thermistor_id[NTC_NCP15WL333] },
378 { .compatible = "ntc,ncp18wb473",
379 .data = &ntc_thermistor_id[NTC_NCP18WB473] },
380 { .compatible = "ntc,ncp21wb473",
381 .data = &ntc_thermistor_id[NTC_NCP21WB473] },
382 { },
383};
384MODULE_DEVICE_TABLE(of, ntc_match);
385
386static struct ntc_thermistor_platform_data *
387ntc_thermistor_parse_dt(struct device *dev)
388{
389 struct iio_channel *chan;
390 enum iio_chan_type type;
391 struct device_node *np = dev->of_node;
392 struct ntc_thermistor_platform_data *pdata;
393 int ret;
394
395 if (!np)
396 return NULL;
397
398 pdata = devm_kzalloc(dev, sizeof(*pdata), GFP_KERNEL);
399 if (!pdata)
400 return ERR_PTR(-ENOMEM);
401
402 chan = devm_iio_channel_get(dev, NULL);
403 if (IS_ERR(chan))
404 return ERR_CAST(chan);
405
406 ret = iio_get_channel_type(chan, &type);
407 if (ret < 0)
408 return ERR_PTR(ret);
409
410 if (type != IIO_VOLTAGE)
411 return ERR_PTR(-EINVAL);
412
413 if (of_property_read_u32(np, "pullup-uv", &pdata->pullup_uv))
414 return ERR_PTR(-ENODEV);
415 if (of_property_read_u32(np, "pullup-ohm", &pdata->pullup_ohm))
416 return ERR_PTR(-ENODEV);
417 if (of_property_read_u32(np, "pulldown-ohm", &pdata->pulldown_ohm))
418 return ERR_PTR(-ENODEV);
419
420 if (of_find_property(np, "connected-positive", NULL))
421 pdata->connect = NTC_CONNECTED_POSITIVE;
422 else /* status change should be possible if not always on. */
423 pdata->connect = NTC_CONNECTED_GROUND;
424
425 pdata->chan = chan;
426 pdata->read_uv = ntc_adc_iio_read;
427
428 return pdata;
429}
430#else
431static struct ntc_thermistor_platform_data *
432ntc_thermistor_parse_dt(struct device *dev)
433{
434 return NULL;
435}
436
437#define ntc_match NULL
438
439#endif
440
441static inline u64 div64_u64_safe(u64 dividend, u64 divisor)
442{
443 if (divisor == 0 && dividend == 0)
444 return 0;
445 if (divisor == 0)
446 return UINT_MAX;
447 return div64_u64(dividend, divisor);
448}
449
450static int get_ohm_of_thermistor(struct ntc_data *data, unsigned int uv)
451{
452 struct ntc_thermistor_platform_data *pdata = data->pdata;
453 u32 puv = pdata->pullup_uv;
454 u64 n, puo, pdo;
455 puo = pdata->pullup_ohm;
456 pdo = pdata->pulldown_ohm;
457
458 if (uv == 0)
459 return (pdata->connect == NTC_CONNECTED_POSITIVE) ?
460 INT_MAX : 0;
461 if (uv >= puv)
462 return (pdata->connect == NTC_CONNECTED_POSITIVE) ?
463 0 : INT_MAX;
464
465 if (pdata->connect == NTC_CONNECTED_POSITIVE && puo == 0)
466 n = div_u64(pdo * (puv - uv), uv);
467 else if (pdata->connect == NTC_CONNECTED_GROUND && pdo == 0)
468 n = div_u64(puo * uv, puv - uv);
469 else if (pdata->connect == NTC_CONNECTED_POSITIVE)
470 n = div64_u64_safe(pdo * puo * (puv - uv),
471 puo * uv - pdo * (puv - uv));
472 else
473 n = div64_u64_safe(pdo * puo * uv, pdo * (puv - uv) - puo * uv);
474
475 if (n > INT_MAX)
476 n = INT_MAX;
477 return n;
478}
479
480static void lookup_comp(struct ntc_data *data, unsigned int ohm,
481 int *i_low, int *i_high)
482{
483 int start, end, mid;
484
485 /*
486 * Handle special cases: Resistance is higher than or equal to
487 * resistance in first table entry, or resistance is lower or equal
488 * to resistance in last table entry.
489 * In these cases, return i_low == i_high, either pointing to the
490 * beginning or to the end of the table depending on the condition.
491 */
492 if (ohm >= data->comp[0].ohm) {
493 *i_low = 0;
494 *i_high = 0;
495 return;
496 }
497 if (ohm <= data->comp[data->n_comp - 1].ohm) {
498 *i_low = data->n_comp - 1;
499 *i_high = data->n_comp - 1;
500 return;
501 }
502
503 /* Do a binary search on compensation table */
504 start = 0;
505 end = data->n_comp;
506 while (start < end) {
507 mid = start + (end - start) / 2;
508 /*
509 * start <= mid < end
510 * data->comp[start].ohm > ohm >= data->comp[end].ohm
511 *
512 * We could check for "ohm == data->comp[mid].ohm" here, but
513 * that is a quite unlikely condition, and we would have to
514 * check again after updating start. Check it at the end instead
515 * for simplicity.
516 */
517 if (ohm >= data->comp[mid].ohm) {
518 end = mid;
519 } else {
520 start = mid + 1;
521 /*
522 * ohm >= data->comp[start].ohm might be true here,
523 * since we set start to mid + 1. In that case, we are
524 * done. We could keep going, but the condition is quite
525 * likely to occur, so it is worth checking for it.
526 */
527 if (ohm >= data->comp[start].ohm)
528 end = start;
529 }
530 /*
531 * start <= end
532 * data->comp[start].ohm >= ohm >= data->comp[end].ohm
533 */
534 }
535 /*
536 * start == end
537 * ohm >= data->comp[end].ohm
538 */
539 *i_low = end;
540 if (ohm == data->comp[end].ohm)
541 *i_high = end;
542 else
543 *i_high = end - 1;
544}
545
546static int get_temp_mc(struct ntc_data *data, unsigned int ohm)
547{
548 int low, high;
549 int temp;
550
551 lookup_comp(data, ohm, &low, &high);
552 if (low == high) {
553 /* Unable to use linear approximation */
554 temp = data->comp[low].temp_c * 1000;
555 } else {
556 temp = data->comp[low].temp_c * 1000 +
557 ((data->comp[high].temp_c - data->comp[low].temp_c) *
558 1000 * ((int)ohm - (int)data->comp[low].ohm)) /
559 ((int)data->comp[high].ohm - (int)data->comp[low].ohm);
560 }
561 return temp;
562}
563
564static int ntc_thermistor_get_ohm(struct ntc_data *data)
565{
566 int read_uv;
567
568 if (data->pdata->read_ohm)
569 return data->pdata->read_ohm();
570
571 if (data->pdata->read_uv) {
572 read_uv = data->pdata->read_uv(data->pdata);
573 if (read_uv < 0)
574 return read_uv;
575 return get_ohm_of_thermistor(data, read_uv);
576 }
577 return -EINVAL;
578}
579
580static int ntc_read(struct device *dev, enum hwmon_sensor_types type,
581 u32 attr, int channel, long *val)
582{
583 struct ntc_data *data = dev_get_drvdata(dev);
584 int ohm;
585
586 switch (type) {
587 case hwmon_temp:
588 switch (attr) {
589 case hwmon_temp_input:
590 ohm = ntc_thermistor_get_ohm(data);
591 if (ohm < 0)
592 return ohm;
593 *val = get_temp_mc(data, ohm);
594 return 0;
595 case hwmon_temp_type:
596 *val = 4;
597 return 0;
598 default:
599 break;
600 }
601 break;
602 default:
603 break;
604 }
605 return -EINVAL;
606}
607
608static umode_t ntc_is_visible(const void *data, enum hwmon_sensor_types type,
609 u32 attr, int channel)
610{
611 if (type == hwmon_temp) {
612 switch (attr) {
613 case hwmon_temp_input:
614 case hwmon_temp_type:
615 return 0444;
616 default:
617 break;
618 }
619 }
620 return 0;
621}
622
623static const struct hwmon_channel_info *ntc_info[] = {
624 HWMON_CHANNEL_INFO(chip, HWMON_C_REGISTER_TZ),
625 HWMON_CHANNEL_INFO(temp, HWMON_T_INPUT | HWMON_T_TYPE),
626 NULL
627};
628
629static const struct hwmon_ops ntc_hwmon_ops = {
630 .is_visible = ntc_is_visible,
631 .read = ntc_read,
632};
633
634static const struct hwmon_chip_info ntc_chip_info = {
635 .ops = &ntc_hwmon_ops,
636 .info = ntc_info,
637};
638
639static int ntc_thermistor_probe(struct platform_device *pdev)
640{
641 struct device *dev = &pdev->dev;
642 const struct of_device_id *of_id =
643 of_match_device(of_match_ptr(ntc_match), dev);
644 const struct platform_device_id *pdev_id;
645 struct ntc_thermistor_platform_data *pdata;
646 struct device *hwmon_dev;
647 struct ntc_data *data;
648
649 pdata = ntc_thermistor_parse_dt(dev);
650 if (IS_ERR(pdata))
651 return PTR_ERR(pdata);
652 else if (pdata == NULL)
653 pdata = dev_get_platdata(dev);
654
655 if (!pdata) {
656 dev_err(dev, "No platform init data supplied.\n");
657 return -ENODEV;
658 }
659
660 /* Either one of the two is required. */
661 if (!pdata->read_uv && !pdata->read_ohm) {
662 dev_err(dev,
663 "Both read_uv and read_ohm missing. Need either one of the two.\n");
664 return -EINVAL;
665 }
666
667 if (pdata->read_uv && pdata->read_ohm) {
668 dev_warn(dev,
669 "Only one of read_uv and read_ohm is needed; ignoring read_uv.\n");
670 pdata->read_uv = NULL;
671 }
672
673 if (pdata->read_uv && (pdata->pullup_uv == 0 ||
674 (pdata->pullup_ohm == 0 && pdata->connect ==
675 NTC_CONNECTED_GROUND) ||
676 (pdata->pulldown_ohm == 0 && pdata->connect ==
677 NTC_CONNECTED_POSITIVE) ||
678 (pdata->connect != NTC_CONNECTED_POSITIVE &&
679 pdata->connect != NTC_CONNECTED_GROUND))) {
680 dev_err(dev, "Required data to use read_uv not supplied.\n");
681 return -EINVAL;
682 }
683
684 data = devm_kzalloc(dev, sizeof(struct ntc_data), GFP_KERNEL);
685 if (!data)
686 return -ENOMEM;
687
688 pdev_id = of_id ? of_id->data : platform_get_device_id(pdev);
689
690 data->pdata = pdata;
691
692 if (pdev_id->driver_data >= ARRAY_SIZE(ntc_type)) {
693 dev_err(dev, "Unknown device type: %lu(%s)\n",
694 pdev_id->driver_data, pdev_id->name);
695 return -EINVAL;
696 }
697
698 data->comp = ntc_type[pdev_id->driver_data].comp;
699 data->n_comp = ntc_type[pdev_id->driver_data].n_comp;
700
701 hwmon_dev = devm_hwmon_device_register_with_info(dev, pdev_id->name,
702 data, &ntc_chip_info,
703 NULL);
704 if (IS_ERR(hwmon_dev)) {
705 dev_err(dev, "unable to register as hwmon device.\n");
706 return PTR_ERR(hwmon_dev);
707 }
708
709 dev_info(dev, "Thermistor type: %s successfully probed.\n",
710 pdev_id->name);
711
712 return 0;
713}
714
715static struct platform_driver ntc_thermistor_driver = {
716 .driver = {
717 .name = "ntc-thermistor",
718 .of_match_table = of_match_ptr(ntc_match),
719 },
720 .probe = ntc_thermistor_probe,
721 .id_table = ntc_thermistor_id,
722};
723
724module_platform_driver(ntc_thermistor_driver);
725
726MODULE_DESCRIPTION("NTC Thermistor Driver");
727MODULE_AUTHOR("MyungJoo Ham <myungjoo.ham@samsung.com>");
728MODULE_LICENSE("GPL");
729MODULE_ALIAS("platform:ntc-thermistor");