xref: /linux/drivers/hwmon/ntc_thermistor.c (revision a3a4a816b4b194c45d0217e8b9e08b2639802cda)
1 /*
2  * ntc_thermistor.c - NTC Thermistors
3  *
4  *  Copyright (C) 2010 Samsung Electronics
5  *  MyungJoo Ham <myungjoo.ham@samsung.com>
6  *
7  * This program is free software; you can redistribute it and/or modify
8  * it under the terms of the GNU General Public License as published by
9  * the Free Software Foundation; either version 2 of the License, or
10  * (at your option) any later version.
11  *
12  * This program is distributed in the hope that it will be useful,
13  * but WITHOUT ANY WARRANTY; without even the implied warranty of
14  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
15  * GNU General Public License for more details.
16  *
17  * You should have received a copy of the GNU General Public License
18  * along with this program; if not, write to the Free Software
19  * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA
20  *
21  */
22 
23 #include <linux/slab.h>
24 #include <linux/module.h>
25 #include <linux/pm_runtime.h>
26 #include <linux/math64.h>
27 #include <linux/platform_device.h>
28 #include <linux/err.h>
29 #include <linux/of.h>
30 #include <linux/of_device.h>
31 
32 #include <linux/platform_data/ntc_thermistor.h>
33 
34 #include <linux/iio/iio.h>
35 #include <linux/iio/machine.h>
36 #include <linux/iio/driver.h>
37 #include <linux/iio/consumer.h>
38 
39 #include <linux/hwmon.h>
40 #include <linux/hwmon-sysfs.h>
41 #include <linux/thermal.h>
42 
43 struct ntc_compensation {
44 	int		temp_c;
45 	unsigned int	ohm;
46 };
47 
48 /* Order matters, ntc_match references the entries by index */
49 static const struct platform_device_id ntc_thermistor_id[] = {
50 	{ "ncp15wb473", TYPE_NCPXXWB473 },
51 	{ "ncp18wb473", TYPE_NCPXXWB473 },
52 	{ "ncp21wb473", TYPE_NCPXXWB473 },
53 	{ "ncp03wb473", TYPE_NCPXXWB473 },
54 	{ "ncp15wl333", TYPE_NCPXXWL333 },
55 	{ "b57330v2103", TYPE_B57330V2103},
56 	{ "ncp03wf104", TYPE_NCPXXWF104 },
57 	{ "ncp15xh103", TYPE_NCPXXXH103 },
58 	{ },
59 };
60 
61 /*
62  * A compensation table should be sorted by the values of .ohm
63  * in descending order.
64  * The following compensation tables are from the specification of Murata NTC
65  * Thermistors Datasheet
66  */
67 static const struct ntc_compensation ncpXXwb473[] = {
68 	{ .temp_c	= -40, .ohm	= 1747920 },
69 	{ .temp_c	= -35, .ohm	= 1245428 },
70 	{ .temp_c	= -30, .ohm	= 898485 },
71 	{ .temp_c	= -25, .ohm	= 655802 },
72 	{ .temp_c	= -20, .ohm	= 483954 },
73 	{ .temp_c	= -15, .ohm	= 360850 },
74 	{ .temp_c	= -10, .ohm	= 271697 },
75 	{ .temp_c	= -5, .ohm	= 206463 },
76 	{ .temp_c	= 0, .ohm	= 158214 },
77 	{ .temp_c	= 5, .ohm	= 122259 },
78 	{ .temp_c	= 10, .ohm	= 95227 },
79 	{ .temp_c	= 15, .ohm	= 74730 },
80 	{ .temp_c	= 20, .ohm	= 59065 },
81 	{ .temp_c	= 25, .ohm	= 47000 },
82 	{ .temp_c	= 30, .ohm	= 37643 },
83 	{ .temp_c	= 35, .ohm	= 30334 },
84 	{ .temp_c	= 40, .ohm	= 24591 },
85 	{ .temp_c	= 45, .ohm	= 20048 },
86 	{ .temp_c	= 50, .ohm	= 16433 },
87 	{ .temp_c	= 55, .ohm	= 13539 },
88 	{ .temp_c	= 60, .ohm	= 11209 },
89 	{ .temp_c	= 65, .ohm	= 9328 },
90 	{ .temp_c	= 70, .ohm	= 7798 },
91 	{ .temp_c	= 75, .ohm	= 6544 },
92 	{ .temp_c	= 80, .ohm	= 5518 },
93 	{ .temp_c	= 85, .ohm	= 4674 },
94 	{ .temp_c	= 90, .ohm	= 3972 },
95 	{ .temp_c	= 95, .ohm	= 3388 },
96 	{ .temp_c	= 100, .ohm	= 2902 },
97 	{ .temp_c	= 105, .ohm	= 2494 },
98 	{ .temp_c	= 110, .ohm	= 2150 },
99 	{ .temp_c	= 115, .ohm	= 1860 },
100 	{ .temp_c	= 120, .ohm	= 1615 },
101 	{ .temp_c	= 125, .ohm	= 1406 },
102 };
103 static const struct ntc_compensation ncpXXwl333[] = {
104 	{ .temp_c	= -40, .ohm	= 1610154 },
105 	{ .temp_c	= -35, .ohm	= 1130850 },
106 	{ .temp_c	= -30, .ohm	= 802609 },
107 	{ .temp_c	= -25, .ohm	= 575385 },
108 	{ .temp_c	= -20, .ohm	= 416464 },
109 	{ .temp_c	= -15, .ohm	= 304219 },
110 	{ .temp_c	= -10, .ohm	= 224193 },
111 	{ .temp_c	= -5, .ohm	= 166623 },
112 	{ .temp_c	= 0, .ohm	= 124850 },
113 	{ .temp_c	= 5, .ohm	= 94287 },
114 	{ .temp_c	= 10, .ohm	= 71747 },
115 	{ .temp_c	= 15, .ohm	= 54996 },
116 	{ .temp_c	= 20, .ohm	= 42455 },
117 	{ .temp_c	= 25, .ohm	= 33000 },
118 	{ .temp_c	= 30, .ohm	= 25822 },
119 	{ .temp_c	= 35, .ohm	= 20335 },
120 	{ .temp_c	= 40, .ohm	= 16115 },
121 	{ .temp_c	= 45, .ohm	= 12849 },
122 	{ .temp_c	= 50, .ohm	= 10306 },
123 	{ .temp_c	= 55, .ohm	= 8314 },
124 	{ .temp_c	= 60, .ohm	= 6746 },
125 	{ .temp_c	= 65, .ohm	= 5503 },
126 	{ .temp_c	= 70, .ohm	= 4513 },
127 	{ .temp_c	= 75, .ohm	= 3721 },
128 	{ .temp_c	= 80, .ohm	= 3084 },
129 	{ .temp_c	= 85, .ohm	= 2569 },
130 	{ .temp_c	= 90, .ohm	= 2151 },
131 	{ .temp_c	= 95, .ohm	= 1809 },
132 	{ .temp_c	= 100, .ohm	= 1529 },
133 	{ .temp_c	= 105, .ohm	= 1299 },
134 	{ .temp_c	= 110, .ohm	= 1108 },
135 	{ .temp_c	= 115, .ohm	= 949 },
136 	{ .temp_c	= 120, .ohm	= 817 },
137 	{ .temp_c	= 125, .ohm	= 707 },
138 };
139 
140 static const struct ntc_compensation ncpXXwf104[] = {
141 	{ .temp_c	= -40, .ohm	= 4397119 },
142 	{ .temp_c	= -35, .ohm	= 3088599 },
143 	{ .temp_c	= -30, .ohm	= 2197225 },
144 	{ .temp_c	= -25, .ohm	= 1581881 },
145 	{ .temp_c	= -20, .ohm	= 1151037 },
146 	{ .temp_c	= -15, .ohm	= 846579 },
147 	{ .temp_c	= -10, .ohm	= 628988 },
148 	{ .temp_c	= -5, .ohm	= 471632 },
149 	{ .temp_c	= 0, .ohm	= 357012 },
150 	{ .temp_c	= 5, .ohm	= 272500 },
151 	{ .temp_c	= 10, .ohm	= 209710 },
152 	{ .temp_c	= 15, .ohm	= 162651 },
153 	{ .temp_c	= 20, .ohm	= 127080 },
154 	{ .temp_c	= 25, .ohm	= 100000 },
155 	{ .temp_c	= 30, .ohm	= 79222 },
156 	{ .temp_c	= 35, .ohm	= 63167 },
157 	{ .temp_c	= 40, .ohm	= 50677 },
158 	{ .temp_c	= 45, .ohm	= 40904 },
159 	{ .temp_c	= 50, .ohm	= 33195 },
160 	{ .temp_c	= 55, .ohm	= 27091 },
161 	{ .temp_c	= 60, .ohm	= 22224 },
162 	{ .temp_c	= 65, .ohm	= 18323 },
163 	{ .temp_c	= 70, .ohm	= 15184 },
164 	{ .temp_c	= 75, .ohm	= 12635 },
165 	{ .temp_c	= 80, .ohm	= 10566 },
166 	{ .temp_c	= 85, .ohm	= 8873 },
167 	{ .temp_c	= 90, .ohm	= 7481 },
168 	{ .temp_c	= 95, .ohm	= 6337 },
169 	{ .temp_c	= 100, .ohm	= 5384 },
170 	{ .temp_c	= 105, .ohm	= 4594 },
171 	{ .temp_c	= 110, .ohm	= 3934 },
172 	{ .temp_c	= 115, .ohm	= 3380 },
173 	{ .temp_c	= 120, .ohm	= 2916 },
174 	{ .temp_c	= 125, .ohm	= 2522 },
175 };
176 
177 static const struct ntc_compensation ncpXXxh103[] = {
178 	{ .temp_c	= -40, .ohm	= 247565 },
179 	{ .temp_c	= -35, .ohm	= 181742 },
180 	{ .temp_c	= -30, .ohm	= 135128 },
181 	{ .temp_c	= -25, .ohm	= 101678 },
182 	{ .temp_c	= -20, .ohm	= 77373 },
183 	{ .temp_c	= -15, .ohm	= 59504 },
184 	{ .temp_c	= -10, .ohm	= 46222 },
185 	{ .temp_c	= -5, .ohm	= 36244 },
186 	{ .temp_c	= 0, .ohm	= 28674 },
187 	{ .temp_c	= 5, .ohm	= 22878 },
188 	{ .temp_c	= 10, .ohm	= 18399 },
189 	{ .temp_c	= 15, .ohm	= 14910 },
190 	{ .temp_c	= 20, .ohm	= 12169 },
191 	{ .temp_c	= 25, .ohm	= 10000 },
192 	{ .temp_c	= 30, .ohm	= 8271 },
193 	{ .temp_c	= 35, .ohm	= 6883 },
194 	{ .temp_c	= 40, .ohm	= 5762 },
195 	{ .temp_c	= 45, .ohm	= 4851 },
196 	{ .temp_c	= 50, .ohm	= 4105 },
197 	{ .temp_c	= 55, .ohm	= 3492 },
198 	{ .temp_c	= 60, .ohm	= 2985 },
199 	{ .temp_c	= 65, .ohm	= 2563 },
200 	{ .temp_c	= 70, .ohm	= 2211 },
201 	{ .temp_c	= 75, .ohm	= 1915 },
202 	{ .temp_c	= 80, .ohm	= 1666 },
203 	{ .temp_c	= 85, .ohm	= 1454 },
204 	{ .temp_c	= 90, .ohm	= 1275 },
205 	{ .temp_c	= 95, .ohm	= 1121 },
206 	{ .temp_c	= 100, .ohm	= 990 },
207 	{ .temp_c	= 105, .ohm	= 876 },
208 	{ .temp_c	= 110, .ohm	= 779 },
209 	{ .temp_c	= 115, .ohm	= 694 },
210 	{ .temp_c	= 120, .ohm	= 620 },
211 	{ .temp_c	= 125, .ohm	= 556 },
212 };
213 
214 /*
215  * The following compensation table is from the specification of EPCOS NTC
216  * Thermistors Datasheet
217  */
218 static const struct ntc_compensation b57330v2103[] = {
219 	{ .temp_c	= -40, .ohm	= 190030 },
220 	{ .temp_c	= -35, .ohm	= 145360 },
221 	{ .temp_c	= -30, .ohm	= 112060 },
222 	{ .temp_c	= -25, .ohm	= 87041 },
223 	{ .temp_c	= -20, .ohm	= 68104 },
224 	{ .temp_c	= -15, .ohm	= 53665 },
225 	{ .temp_c	= -10, .ohm	= 42576 },
226 	{ .temp_c	= -5, .ohm	= 34001 },
227 	{ .temp_c	= 0, .ohm	= 27326 },
228 	{ .temp_c	= 5, .ohm	= 22096 },
229 	{ .temp_c	= 10, .ohm	= 17973 },
230 	{ .temp_c	= 15, .ohm	= 14703 },
231 	{ .temp_c	= 20, .ohm	= 12090 },
232 	{ .temp_c	= 25, .ohm	= 10000 },
233 	{ .temp_c	= 30, .ohm	= 8311 },
234 	{ .temp_c	= 35, .ohm	= 6941 },
235 	{ .temp_c	= 40, .ohm	= 5825 },
236 	{ .temp_c	= 45, .ohm	= 4911 },
237 	{ .temp_c	= 50, .ohm	= 4158 },
238 	{ .temp_c	= 55, .ohm	= 3536 },
239 	{ .temp_c	= 60, .ohm	= 3019 },
240 	{ .temp_c	= 65, .ohm	= 2588 },
241 	{ .temp_c	= 70, .ohm	= 2227 },
242 	{ .temp_c	= 75, .ohm	= 1924 },
243 	{ .temp_c	= 80, .ohm	= 1668 },
244 	{ .temp_c	= 85, .ohm	= 1451 },
245 	{ .temp_c	= 90, .ohm	= 1266 },
246 	{ .temp_c	= 95, .ohm	= 1108 },
247 	{ .temp_c	= 100, .ohm	= 973 },
248 	{ .temp_c	= 105, .ohm	= 857 },
249 	{ .temp_c	= 110, .ohm	= 757 },
250 	{ .temp_c	= 115, .ohm	= 671 },
251 	{ .temp_c	= 120, .ohm	= 596 },
252 	{ .temp_c	= 125, .ohm	= 531 },
253 };
254 
255 struct ntc_data {
256 	struct ntc_thermistor_platform_data *pdata;
257 	const struct ntc_compensation *comp;
258 	int n_comp;
259 };
260 
261 #if defined(CONFIG_OF) && IS_ENABLED(CONFIG_IIO)
262 static int ntc_adc_iio_read(struct ntc_thermistor_platform_data *pdata)
263 {
264 	struct iio_channel *channel = pdata->chan;
265 	int raw, uv, ret;
266 
267 	ret = iio_read_channel_raw(channel, &raw);
268 	if (ret < 0) {
269 		pr_err("read channel() error: %d\n", ret);
270 		return ret;
271 	}
272 
273 	ret = iio_convert_raw_to_processed(channel, raw, &uv, 1000);
274 	if (ret < 0) {
275 		/* Assume 12 bit ADC with vref at pullup_uv */
276 		uv = (pdata->pullup_uv * (s64)raw) >> 12;
277 	}
278 
279 	return uv;
280 }
281 
282 static const struct of_device_id ntc_match[] = {
283 	{ .compatible = "murata,ncp15wb473",
284 		.data = &ntc_thermistor_id[0] },
285 	{ .compatible = "murata,ncp18wb473",
286 		.data = &ntc_thermistor_id[1] },
287 	{ .compatible = "murata,ncp21wb473",
288 		.data = &ntc_thermistor_id[2] },
289 	{ .compatible = "murata,ncp03wb473",
290 		.data = &ntc_thermistor_id[3] },
291 	{ .compatible = "murata,ncp15wl333",
292 		.data = &ntc_thermistor_id[4] },
293 	{ .compatible = "epcos,b57330v2103",
294 		.data = &ntc_thermistor_id[5]},
295 	{ .compatible = "murata,ncp03wf104",
296 		.data = &ntc_thermistor_id[6] },
297 	{ .compatible = "murata,ncp15xh103",
298 		.data = &ntc_thermistor_id[7] },
299 
300 	/* Usage of vendor name "ntc" is deprecated */
301 	{ .compatible = "ntc,ncp15wb473",
302 		.data = &ntc_thermistor_id[0] },
303 	{ .compatible = "ntc,ncp18wb473",
304 		.data = &ntc_thermistor_id[1] },
305 	{ .compatible = "ntc,ncp21wb473",
306 		.data = &ntc_thermistor_id[2] },
307 	{ .compatible = "ntc,ncp03wb473",
308 		.data = &ntc_thermistor_id[3] },
309 	{ .compatible = "ntc,ncp15wl333",
310 		.data = &ntc_thermistor_id[4] },
311 	{ },
312 };
313 MODULE_DEVICE_TABLE(of, ntc_match);
314 
315 static struct ntc_thermistor_platform_data *
316 ntc_thermistor_parse_dt(struct device *dev)
317 {
318 	struct iio_channel *chan;
319 	enum iio_chan_type type;
320 	struct device_node *np = dev->of_node;
321 	struct ntc_thermistor_platform_data *pdata;
322 	int ret;
323 
324 	if (!np)
325 		return NULL;
326 
327 	pdata = devm_kzalloc(dev, sizeof(*pdata), GFP_KERNEL);
328 	if (!pdata)
329 		return ERR_PTR(-ENOMEM);
330 
331 	chan = devm_iio_channel_get(dev, NULL);
332 	if (IS_ERR(chan))
333 		return ERR_CAST(chan);
334 
335 	ret = iio_get_channel_type(chan, &type);
336 	if (ret < 0)
337 		return ERR_PTR(ret);
338 
339 	if (type != IIO_VOLTAGE)
340 		return ERR_PTR(-EINVAL);
341 
342 	if (of_property_read_u32(np, "pullup-uv", &pdata->pullup_uv))
343 		return ERR_PTR(-ENODEV);
344 	if (of_property_read_u32(np, "pullup-ohm", &pdata->pullup_ohm))
345 		return ERR_PTR(-ENODEV);
346 	if (of_property_read_u32(np, "pulldown-ohm", &pdata->pulldown_ohm))
347 		return ERR_PTR(-ENODEV);
348 
349 	if (of_find_property(np, "connected-positive", NULL))
350 		pdata->connect = NTC_CONNECTED_POSITIVE;
351 	else /* status change should be possible if not always on. */
352 		pdata->connect = NTC_CONNECTED_GROUND;
353 
354 	pdata->chan = chan;
355 	pdata->read_uv = ntc_adc_iio_read;
356 
357 	return pdata;
358 }
359 #else
360 static struct ntc_thermistor_platform_data *
361 ntc_thermistor_parse_dt(struct device *dev)
362 {
363 	return NULL;
364 }
365 
366 #define ntc_match	NULL
367 
368 #endif
369 
370 static inline u64 div64_u64_safe(u64 dividend, u64 divisor)
371 {
372 	if (divisor == 0 && dividend == 0)
373 		return 0;
374 	if (divisor == 0)
375 		return UINT_MAX;
376 	return div64_u64(dividend, divisor);
377 }
378 
379 static int get_ohm_of_thermistor(struct ntc_data *data, unsigned int uv)
380 {
381 	struct ntc_thermistor_platform_data *pdata = data->pdata;
382 	u32 puv = pdata->pullup_uv;
383 	u64 n, puo, pdo;
384 	puo = pdata->pullup_ohm;
385 	pdo = pdata->pulldown_ohm;
386 
387 	if (uv == 0)
388 		return (pdata->connect == NTC_CONNECTED_POSITIVE) ?
389 			INT_MAX : 0;
390 	if (uv >= puv)
391 		return (pdata->connect == NTC_CONNECTED_POSITIVE) ?
392 			0 : INT_MAX;
393 
394 	if (pdata->connect == NTC_CONNECTED_POSITIVE && puo == 0)
395 		n = div_u64(pdo * (puv - uv), uv);
396 	else if (pdata->connect == NTC_CONNECTED_GROUND && pdo == 0)
397 		n = div_u64(puo * uv, puv - uv);
398 	else if (pdata->connect == NTC_CONNECTED_POSITIVE)
399 		n = div64_u64_safe(pdo * puo * (puv - uv),
400 				puo * uv - pdo * (puv - uv));
401 	else
402 		n = div64_u64_safe(pdo * puo * uv, pdo * (puv - uv) - puo * uv);
403 
404 	if (n > INT_MAX)
405 		n = INT_MAX;
406 	return n;
407 }
408 
409 static void lookup_comp(struct ntc_data *data, unsigned int ohm,
410 			int *i_low, int *i_high)
411 {
412 	int start, end, mid;
413 
414 	/*
415 	 * Handle special cases: Resistance is higher than or equal to
416 	 * resistance in first table entry, or resistance is lower or equal
417 	 * to resistance in last table entry.
418 	 * In these cases, return i_low == i_high, either pointing to the
419 	 * beginning or to the end of the table depending on the condition.
420 	 */
421 	if (ohm >= data->comp[0].ohm) {
422 		*i_low = 0;
423 		*i_high = 0;
424 		return;
425 	}
426 	if (ohm <= data->comp[data->n_comp - 1].ohm) {
427 		*i_low = data->n_comp - 1;
428 		*i_high = data->n_comp - 1;
429 		return;
430 	}
431 
432 	/* Do a binary search on compensation table */
433 	start = 0;
434 	end = data->n_comp;
435 	while (start < end) {
436 		mid = start + (end - start) / 2;
437 		/*
438 		 * start <= mid < end
439 		 * data->comp[start].ohm > ohm >= data->comp[end].ohm
440 		 *
441 		 * We could check for "ohm == data->comp[mid].ohm" here, but
442 		 * that is a quite unlikely condition, and we would have to
443 		 * check again after updating start. Check it at the end instead
444 		 * for simplicity.
445 		 */
446 		if (ohm >= data->comp[mid].ohm) {
447 			end = mid;
448 		} else {
449 			start = mid + 1;
450 			/*
451 			 * ohm >= data->comp[start].ohm might be true here,
452 			 * since we set start to mid + 1. In that case, we are
453 			 * done. We could keep going, but the condition is quite
454 			 * likely to occur, so it is worth checking for it.
455 			 */
456 			if (ohm >= data->comp[start].ohm)
457 				end = start;
458 		}
459 		/*
460 		 * start <= end
461 		 * data->comp[start].ohm >= ohm >= data->comp[end].ohm
462 		 */
463 	}
464 	/*
465 	 * start == end
466 	 * ohm >= data->comp[end].ohm
467 	 */
468 	*i_low = end;
469 	if (ohm == data->comp[end].ohm)
470 		*i_high = end;
471 	else
472 		*i_high = end - 1;
473 }
474 
475 static int get_temp_mc(struct ntc_data *data, unsigned int ohm)
476 {
477 	int low, high;
478 	int temp;
479 
480 	lookup_comp(data, ohm, &low, &high);
481 	if (low == high) {
482 		/* Unable to use linear approximation */
483 		temp = data->comp[low].temp_c * 1000;
484 	} else {
485 		temp = data->comp[low].temp_c * 1000 +
486 			((data->comp[high].temp_c - data->comp[low].temp_c) *
487 			 1000 * ((int)ohm - (int)data->comp[low].ohm)) /
488 			((int)data->comp[high].ohm - (int)data->comp[low].ohm);
489 	}
490 	return temp;
491 }
492 
493 static int ntc_thermistor_get_ohm(struct ntc_data *data)
494 {
495 	int read_uv;
496 
497 	if (data->pdata->read_ohm)
498 		return data->pdata->read_ohm();
499 
500 	if (data->pdata->read_uv) {
501 		read_uv = data->pdata->read_uv(data->pdata);
502 		if (read_uv < 0)
503 			return read_uv;
504 		return get_ohm_of_thermistor(data, read_uv);
505 	}
506 	return -EINVAL;
507 }
508 
509 static int ntc_read_temp(void *data, int *temp)
510 {
511 	int ohm;
512 
513 	ohm = ntc_thermistor_get_ohm(data);
514 	if (ohm < 0)
515 		return ohm;
516 
517 	*temp = get_temp_mc(data, ohm);
518 
519 	return 0;
520 }
521 
522 static ssize_t ntc_show_type(struct device *dev,
523 		struct device_attribute *attr, char *buf)
524 {
525 	return sprintf(buf, "4\n");
526 }
527 
528 static ssize_t ntc_show_temp(struct device *dev,
529 		struct device_attribute *attr, char *buf)
530 {
531 	struct ntc_data *data = dev_get_drvdata(dev);
532 	int ohm;
533 
534 	ohm = ntc_thermistor_get_ohm(data);
535 	if (ohm < 0)
536 		return ohm;
537 
538 	return sprintf(buf, "%d\n", get_temp_mc(data, ohm));
539 }
540 
541 static SENSOR_DEVICE_ATTR(temp1_type, S_IRUGO, ntc_show_type, NULL, 0);
542 static SENSOR_DEVICE_ATTR(temp1_input, S_IRUGO, ntc_show_temp, NULL, 0);
543 
544 static struct attribute *ntc_attrs[] = {
545 	&sensor_dev_attr_temp1_type.dev_attr.attr,
546 	&sensor_dev_attr_temp1_input.dev_attr.attr,
547 	NULL,
548 };
549 ATTRIBUTE_GROUPS(ntc);
550 
551 static const struct thermal_zone_of_device_ops ntc_of_thermal_ops = {
552 	.get_temp = ntc_read_temp,
553 };
554 
555 static int ntc_thermistor_probe(struct platform_device *pdev)
556 {
557 	struct thermal_zone_device *tz;
558 	struct device *dev = &pdev->dev;
559 	const struct of_device_id *of_id =
560 			of_match_device(of_match_ptr(ntc_match), dev);
561 	const struct platform_device_id *pdev_id;
562 	struct ntc_thermistor_platform_data *pdata;
563 	struct device *hwmon_dev;
564 	struct ntc_data *data;
565 
566 	pdata = ntc_thermistor_parse_dt(dev);
567 	if (IS_ERR(pdata))
568 		return PTR_ERR(pdata);
569 	else if (pdata == NULL)
570 		pdata = dev_get_platdata(dev);
571 
572 	if (!pdata) {
573 		dev_err(dev, "No platform init data supplied.\n");
574 		return -ENODEV;
575 	}
576 
577 	/* Either one of the two is required. */
578 	if (!pdata->read_uv && !pdata->read_ohm) {
579 		dev_err(dev,
580 			"Both read_uv and read_ohm missing. Need either one of the two.\n");
581 		return -EINVAL;
582 	}
583 
584 	if (pdata->read_uv && pdata->read_ohm) {
585 		dev_warn(dev,
586 			 "Only one of read_uv and read_ohm is needed; ignoring read_uv.\n");
587 		pdata->read_uv = NULL;
588 	}
589 
590 	if (pdata->read_uv && (pdata->pullup_uv == 0 ||
591 				(pdata->pullup_ohm == 0 && pdata->connect ==
592 				 NTC_CONNECTED_GROUND) ||
593 				(pdata->pulldown_ohm == 0 && pdata->connect ==
594 				 NTC_CONNECTED_POSITIVE) ||
595 				(pdata->connect != NTC_CONNECTED_POSITIVE &&
596 				 pdata->connect != NTC_CONNECTED_GROUND))) {
597 		dev_err(dev, "Required data to use read_uv not supplied.\n");
598 		return -EINVAL;
599 	}
600 
601 	data = devm_kzalloc(dev, sizeof(struct ntc_data), GFP_KERNEL);
602 	if (!data)
603 		return -ENOMEM;
604 
605 	pdev_id = of_id ? of_id->data : platform_get_device_id(pdev);
606 
607 	data->pdata = pdata;
608 
609 	switch (pdev_id->driver_data) {
610 	case TYPE_NCPXXWB473:
611 		data->comp = ncpXXwb473;
612 		data->n_comp = ARRAY_SIZE(ncpXXwb473);
613 		break;
614 	case TYPE_NCPXXWL333:
615 		data->comp = ncpXXwl333;
616 		data->n_comp = ARRAY_SIZE(ncpXXwl333);
617 		break;
618 	case TYPE_B57330V2103:
619 		data->comp = b57330v2103;
620 		data->n_comp = ARRAY_SIZE(b57330v2103);
621 		break;
622 	case TYPE_NCPXXWF104:
623 		data->comp = ncpXXwf104;
624 		data->n_comp = ARRAY_SIZE(ncpXXwf104);
625 		break;
626 	case TYPE_NCPXXXH103:
627 		data->comp = ncpXXxh103;
628 		data->n_comp = ARRAY_SIZE(ncpXXxh103);
629 		break;
630 	default:
631 		dev_err(dev, "Unknown device type: %lu(%s)\n",
632 				pdev_id->driver_data, pdev_id->name);
633 		return -EINVAL;
634 	}
635 
636 	hwmon_dev = devm_hwmon_device_register_with_groups(dev, pdev_id->name,
637 							   data, ntc_groups);
638 	if (IS_ERR(hwmon_dev)) {
639 		dev_err(dev, "unable to register as hwmon device.\n");
640 		return PTR_ERR(hwmon_dev);
641 	}
642 
643 	dev_info(dev, "Thermistor type: %s successfully probed.\n",
644 		 pdev_id->name);
645 
646 	tz = devm_thermal_zone_of_sensor_register(dev, 0, data,
647 						  &ntc_of_thermal_ops);
648 	if (IS_ERR(tz))
649 		dev_dbg(dev, "Failed to register to thermal fw.\n");
650 
651 	return 0;
652 }
653 
654 static struct platform_driver ntc_thermistor_driver = {
655 	.driver = {
656 		.name = "ntc-thermistor",
657 		.of_match_table = of_match_ptr(ntc_match),
658 	},
659 	.probe = ntc_thermistor_probe,
660 	.id_table = ntc_thermistor_id,
661 };
662 
663 module_platform_driver(ntc_thermistor_driver);
664 
665 MODULE_DESCRIPTION("NTC Thermistor Driver");
666 MODULE_AUTHOR("MyungJoo Ham <myungjoo.ham@samsung.com>");
667 MODULE_LICENSE("GPL");
668 MODULE_ALIAS("platform:ntc-thermistor");
669