xref: /linux/drivers/hwmon/ntc_thermistor.c (revision 110e6f26af80dfd90b6e5c645b1aed7228aa580d)
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 device *hwmon_dev;
257 	struct ntc_thermistor_platform_data *pdata;
258 	const struct ntc_compensation *comp;
259 	struct device *dev;
260 	int n_comp;
261 	char name[PLATFORM_NAME_SIZE];
262 	struct thermal_zone_device *tz;
263 };
264 
265 #if defined(CONFIG_OF) && IS_ENABLED(CONFIG_IIO)
266 static int ntc_adc_iio_read(struct ntc_thermistor_platform_data *pdata)
267 {
268 	struct iio_channel *channel = pdata->chan;
269 	int raw, uv, ret;
270 
271 	ret = iio_read_channel_raw(channel, &raw);
272 	if (ret < 0) {
273 		pr_err("read channel() error: %d\n", ret);
274 		return ret;
275 	}
276 
277 	ret = iio_convert_raw_to_processed(channel, raw, &uv, 1000);
278 	if (ret < 0) {
279 		/* Assume 12 bit ADC with vref at pullup_uv */
280 		uv = (pdata->pullup_uv * (s64)raw) >> 12;
281 	}
282 
283 	return uv;
284 }
285 
286 static const struct of_device_id ntc_match[] = {
287 	{ .compatible = "murata,ncp15wb473",
288 		.data = &ntc_thermistor_id[0] },
289 	{ .compatible = "murata,ncp18wb473",
290 		.data = &ntc_thermistor_id[1] },
291 	{ .compatible = "murata,ncp21wb473",
292 		.data = &ntc_thermistor_id[2] },
293 	{ .compatible = "murata,ncp03wb473",
294 		.data = &ntc_thermistor_id[3] },
295 	{ .compatible = "murata,ncp15wl333",
296 		.data = &ntc_thermistor_id[4] },
297 	{ .compatible = "epcos,b57330v2103",
298 		.data = &ntc_thermistor_id[5]},
299 	{ .compatible = "murata,ncp03wf104",
300 		.data = &ntc_thermistor_id[6] },
301 	{ .compatible = "murata,ncp15xh103",
302 		.data = &ntc_thermistor_id[7] },
303 
304 	/* Usage of vendor name "ntc" is deprecated */
305 	{ .compatible = "ntc,ncp15wb473",
306 		.data = &ntc_thermistor_id[0] },
307 	{ .compatible = "ntc,ncp18wb473",
308 		.data = &ntc_thermistor_id[1] },
309 	{ .compatible = "ntc,ncp21wb473",
310 		.data = &ntc_thermistor_id[2] },
311 	{ .compatible = "ntc,ncp03wb473",
312 		.data = &ntc_thermistor_id[3] },
313 	{ .compatible = "ntc,ncp15wl333",
314 		.data = &ntc_thermistor_id[4] },
315 	{ },
316 };
317 MODULE_DEVICE_TABLE(of, ntc_match);
318 
319 static struct ntc_thermistor_platform_data *
320 ntc_thermistor_parse_dt(struct platform_device *pdev)
321 {
322 	struct iio_channel *chan;
323 	enum iio_chan_type type;
324 	struct device_node *np = pdev->dev.of_node;
325 	struct ntc_thermistor_platform_data *pdata;
326 	int ret;
327 
328 	if (!np)
329 		return NULL;
330 
331 	pdata = devm_kzalloc(&pdev->dev, sizeof(*pdata), GFP_KERNEL);
332 	if (!pdata)
333 		return ERR_PTR(-ENOMEM);
334 
335 	chan = iio_channel_get(&pdev->dev, NULL);
336 	if (IS_ERR(chan))
337 		return ERR_CAST(chan);
338 
339 	ret = iio_get_channel_type(chan, &type);
340 	if (ret < 0)
341 		return ERR_PTR(ret);
342 
343 	if (type != IIO_VOLTAGE)
344 		return ERR_PTR(-EINVAL);
345 
346 	if (of_property_read_u32(np, "pullup-uv", &pdata->pullup_uv))
347 		return ERR_PTR(-ENODEV);
348 	if (of_property_read_u32(np, "pullup-ohm", &pdata->pullup_ohm))
349 		return ERR_PTR(-ENODEV);
350 	if (of_property_read_u32(np, "pulldown-ohm", &pdata->pulldown_ohm))
351 		return ERR_PTR(-ENODEV);
352 
353 	if (of_find_property(np, "connected-positive", NULL))
354 		pdata->connect = NTC_CONNECTED_POSITIVE;
355 	else /* status change should be possible if not always on. */
356 		pdata->connect = NTC_CONNECTED_GROUND;
357 
358 	pdata->chan = chan;
359 	pdata->read_uv = ntc_adc_iio_read;
360 
361 	return pdata;
362 }
363 static void ntc_iio_channel_release(struct ntc_thermistor_platform_data *pdata)
364 {
365 	if (pdata->chan)
366 		iio_channel_release(pdata->chan);
367 }
368 #else
369 static struct ntc_thermistor_platform_data *
370 ntc_thermistor_parse_dt(struct platform_device *pdev)
371 {
372 	return NULL;
373 }
374 
375 #define ntc_match	NULL
376 
377 static void ntc_iio_channel_release(struct ntc_thermistor_platform_data *pdata)
378 { }
379 #endif
380 
381 static inline u64 div64_u64_safe(u64 dividend, u64 divisor)
382 {
383 	if (divisor == 0 && dividend == 0)
384 		return 0;
385 	if (divisor == 0)
386 		return UINT_MAX;
387 	return div64_u64(dividend, divisor);
388 }
389 
390 static int get_ohm_of_thermistor(struct ntc_data *data, unsigned int uv)
391 {
392 	struct ntc_thermistor_platform_data *pdata = data->pdata;
393 	u32 puv = pdata->pullup_uv;
394 	u64 n, puo, pdo;
395 	puo = pdata->pullup_ohm;
396 	pdo = pdata->pulldown_ohm;
397 
398 	if (uv == 0)
399 		return (pdata->connect == NTC_CONNECTED_POSITIVE) ?
400 			INT_MAX : 0;
401 	if (uv >= puv)
402 		return (pdata->connect == NTC_CONNECTED_POSITIVE) ?
403 			0 : INT_MAX;
404 
405 	if (pdata->connect == NTC_CONNECTED_POSITIVE && puo == 0)
406 		n = div_u64(pdo * (puv - uv), uv);
407 	else if (pdata->connect == NTC_CONNECTED_GROUND && pdo == 0)
408 		n = div_u64(puo * uv, puv - uv);
409 	else if (pdata->connect == NTC_CONNECTED_POSITIVE)
410 		n = div64_u64_safe(pdo * puo * (puv - uv),
411 				puo * uv - pdo * (puv - uv));
412 	else
413 		n = div64_u64_safe(pdo * puo * uv, pdo * (puv - uv) - puo * uv);
414 
415 	if (n > INT_MAX)
416 		n = INT_MAX;
417 	return n;
418 }
419 
420 static void lookup_comp(struct ntc_data *data, unsigned int ohm,
421 			int *i_low, int *i_high)
422 {
423 	int start, end, mid;
424 
425 	/*
426 	 * Handle special cases: Resistance is higher than or equal to
427 	 * resistance in first table entry, or resistance is lower or equal
428 	 * to resistance in last table entry.
429 	 * In these cases, return i_low == i_high, either pointing to the
430 	 * beginning or to the end of the table depending on the condition.
431 	 */
432 	if (ohm >= data->comp[0].ohm) {
433 		*i_low = 0;
434 		*i_high = 0;
435 		return;
436 	}
437 	if (ohm <= data->comp[data->n_comp - 1].ohm) {
438 		*i_low = data->n_comp - 1;
439 		*i_high = data->n_comp - 1;
440 		return;
441 	}
442 
443 	/* Do a binary search on compensation table */
444 	start = 0;
445 	end = data->n_comp;
446 	while (start < end) {
447 		mid = start + (end - start) / 2;
448 		/*
449 		 * start <= mid < end
450 		 * data->comp[start].ohm > ohm >= data->comp[end].ohm
451 		 *
452 		 * We could check for "ohm == data->comp[mid].ohm" here, but
453 		 * that is a quite unlikely condition, and we would have to
454 		 * check again after updating start. Check it at the end instead
455 		 * for simplicity.
456 		 */
457 		if (ohm >= data->comp[mid].ohm) {
458 			end = mid;
459 		} else {
460 			start = mid + 1;
461 			/*
462 			 * ohm >= data->comp[start].ohm might be true here,
463 			 * since we set start to mid + 1. In that case, we are
464 			 * done. We could keep going, but the condition is quite
465 			 * likely to occur, so it is worth checking for it.
466 			 */
467 			if (ohm >= data->comp[start].ohm)
468 				end = start;
469 		}
470 		/*
471 		 * start <= end
472 		 * data->comp[start].ohm >= ohm >= data->comp[end].ohm
473 		 */
474 	}
475 	/*
476 	 * start == end
477 	 * ohm >= data->comp[end].ohm
478 	 */
479 	*i_low = end;
480 	if (ohm == data->comp[end].ohm)
481 		*i_high = end;
482 	else
483 		*i_high = end - 1;
484 }
485 
486 static int get_temp_mc(struct ntc_data *data, unsigned int ohm)
487 {
488 	int low, high;
489 	int temp;
490 
491 	lookup_comp(data, ohm, &low, &high);
492 	if (low == high) {
493 		/* Unable to use linear approximation */
494 		temp = data->comp[low].temp_c * 1000;
495 	} else {
496 		temp = data->comp[low].temp_c * 1000 +
497 			((data->comp[high].temp_c - data->comp[low].temp_c) *
498 			 1000 * ((int)ohm - (int)data->comp[low].ohm)) /
499 			((int)data->comp[high].ohm - (int)data->comp[low].ohm);
500 	}
501 	return temp;
502 }
503 
504 static int ntc_thermistor_get_ohm(struct ntc_data *data)
505 {
506 	int read_uv;
507 
508 	if (data->pdata->read_ohm)
509 		return data->pdata->read_ohm();
510 
511 	if (data->pdata->read_uv) {
512 		read_uv = data->pdata->read_uv(data->pdata);
513 		if (read_uv < 0)
514 			return read_uv;
515 		return get_ohm_of_thermistor(data, read_uv);
516 	}
517 	return -EINVAL;
518 }
519 
520 static int ntc_read_temp(void *dev, int *temp)
521 {
522 	struct ntc_data *data = dev_get_drvdata(dev);
523 	int ohm;
524 
525 	ohm = ntc_thermistor_get_ohm(data);
526 	if (ohm < 0)
527 		return ohm;
528 
529 	*temp = get_temp_mc(data, ohm);
530 
531 	return 0;
532 }
533 
534 static ssize_t ntc_show_name(struct device *dev,
535 		struct device_attribute *attr, char *buf)
536 {
537 	struct ntc_data *data = dev_get_drvdata(dev);
538 
539 	return sprintf(buf, "%s\n", data->name);
540 }
541 
542 static ssize_t ntc_show_type(struct device *dev,
543 		struct device_attribute *attr, char *buf)
544 {
545 	return sprintf(buf, "4\n");
546 }
547 
548 static ssize_t ntc_show_temp(struct device *dev,
549 		struct device_attribute *attr, char *buf)
550 {
551 	struct ntc_data *data = dev_get_drvdata(dev);
552 	int ohm;
553 
554 	ohm = ntc_thermistor_get_ohm(data);
555 	if (ohm < 0)
556 		return ohm;
557 
558 	return sprintf(buf, "%d\n", get_temp_mc(data, ohm));
559 }
560 
561 static SENSOR_DEVICE_ATTR(temp1_type, S_IRUGO, ntc_show_type, NULL, 0);
562 static SENSOR_DEVICE_ATTR(temp1_input, S_IRUGO, ntc_show_temp, NULL, 0);
563 static DEVICE_ATTR(name, S_IRUGO, ntc_show_name, NULL);
564 
565 static struct attribute *ntc_attributes[] = {
566 	&dev_attr_name.attr,
567 	&sensor_dev_attr_temp1_type.dev_attr.attr,
568 	&sensor_dev_attr_temp1_input.dev_attr.attr,
569 	NULL,
570 };
571 
572 static const struct attribute_group ntc_attr_group = {
573 	.attrs = ntc_attributes,
574 };
575 
576 static const struct thermal_zone_of_device_ops ntc_of_thermal_ops = {
577 	.get_temp = ntc_read_temp,
578 };
579 
580 static int ntc_thermistor_probe(struct platform_device *pdev)
581 {
582 	const struct of_device_id *of_id =
583 			of_match_device(of_match_ptr(ntc_match), &pdev->dev);
584 	const struct platform_device_id *pdev_id;
585 	struct ntc_thermistor_platform_data *pdata;
586 	struct ntc_data *data;
587 	int ret;
588 
589 	pdata = ntc_thermistor_parse_dt(pdev);
590 	if (IS_ERR(pdata))
591 		return PTR_ERR(pdata);
592 	else if (pdata == NULL)
593 		pdata = dev_get_platdata(&pdev->dev);
594 
595 	if (!pdata) {
596 		dev_err(&pdev->dev, "No platform init data supplied.\n");
597 		return -ENODEV;
598 	}
599 
600 	/* Either one of the two is required. */
601 	if (!pdata->read_uv && !pdata->read_ohm) {
602 		dev_err(&pdev->dev,
603 			"Both read_uv and read_ohm missing. Need either one of the two.\n");
604 		return -EINVAL;
605 	}
606 
607 	if (pdata->read_uv && pdata->read_ohm) {
608 		dev_warn(&pdev->dev,
609 			 "Only one of read_uv and read_ohm is needed; ignoring read_uv.\n");
610 		pdata->read_uv = NULL;
611 	}
612 
613 	if (pdata->read_uv && (pdata->pullup_uv == 0 ||
614 				(pdata->pullup_ohm == 0 && pdata->connect ==
615 				 NTC_CONNECTED_GROUND) ||
616 				(pdata->pulldown_ohm == 0 && pdata->connect ==
617 				 NTC_CONNECTED_POSITIVE) ||
618 				(pdata->connect != NTC_CONNECTED_POSITIVE &&
619 				 pdata->connect != NTC_CONNECTED_GROUND))) {
620 		dev_err(&pdev->dev,
621 			"Required data to use read_uv not supplied.\n");
622 		return -EINVAL;
623 	}
624 
625 	data = devm_kzalloc(&pdev->dev, sizeof(struct ntc_data), GFP_KERNEL);
626 	if (!data)
627 		return -ENOMEM;
628 
629 	pdev_id = of_id ? of_id->data : platform_get_device_id(pdev);
630 
631 	data->dev = &pdev->dev;
632 	data->pdata = pdata;
633 	strlcpy(data->name, pdev_id->name, sizeof(data->name));
634 
635 	switch (pdev_id->driver_data) {
636 	case TYPE_NCPXXWB473:
637 		data->comp = ncpXXwb473;
638 		data->n_comp = ARRAY_SIZE(ncpXXwb473);
639 		break;
640 	case TYPE_NCPXXWL333:
641 		data->comp = ncpXXwl333;
642 		data->n_comp = ARRAY_SIZE(ncpXXwl333);
643 		break;
644 	case TYPE_B57330V2103:
645 		data->comp = b57330v2103;
646 		data->n_comp = ARRAY_SIZE(b57330v2103);
647 		break;
648 	case TYPE_NCPXXWF104:
649 		data->comp = ncpXXwf104;
650 		data->n_comp = ARRAY_SIZE(ncpXXwf104);
651 		break;
652 	case TYPE_NCPXXXH103:
653 		data->comp = ncpXXxh103;
654 		data->n_comp = ARRAY_SIZE(ncpXXxh103);
655 		break;
656 	default:
657 		dev_err(&pdev->dev, "Unknown device type: %lu(%s)\n",
658 				pdev_id->driver_data, pdev_id->name);
659 		return -EINVAL;
660 	}
661 
662 	platform_set_drvdata(pdev, data);
663 
664 	ret = sysfs_create_group(&data->dev->kobj, &ntc_attr_group);
665 	if (ret) {
666 		dev_err(data->dev, "unable to create sysfs files\n");
667 		return ret;
668 	}
669 
670 	data->hwmon_dev = hwmon_device_register(data->dev);
671 	if (IS_ERR(data->hwmon_dev)) {
672 		dev_err(data->dev, "unable to register as hwmon device.\n");
673 		ret = PTR_ERR(data->hwmon_dev);
674 		goto err_after_sysfs;
675 	}
676 
677 	dev_info(&pdev->dev, "Thermistor type: %s successfully probed.\n",
678 								pdev_id->name);
679 
680 	data->tz = thermal_zone_of_sensor_register(data->dev, 0, data->dev,
681 						   &ntc_of_thermal_ops);
682 	if (IS_ERR(data->tz)) {
683 		dev_dbg(&pdev->dev, "Failed to register to thermal fw.\n");
684 		data->tz = NULL;
685 	}
686 
687 	return 0;
688 err_after_sysfs:
689 	sysfs_remove_group(&data->dev->kobj, &ntc_attr_group);
690 	ntc_iio_channel_release(pdata);
691 	return ret;
692 }
693 
694 static int ntc_thermistor_remove(struct platform_device *pdev)
695 {
696 	struct ntc_data *data = platform_get_drvdata(pdev);
697 	struct ntc_thermistor_platform_data *pdata = data->pdata;
698 
699 	hwmon_device_unregister(data->hwmon_dev);
700 	sysfs_remove_group(&data->dev->kobj, &ntc_attr_group);
701 	ntc_iio_channel_release(pdata);
702 
703 	thermal_zone_of_sensor_unregister(data->dev, data->tz);
704 
705 	return 0;
706 }
707 
708 static struct platform_driver ntc_thermistor_driver = {
709 	.driver = {
710 		.name = "ntc-thermistor",
711 		.of_match_table = of_match_ptr(ntc_match),
712 	},
713 	.probe = ntc_thermistor_probe,
714 	.remove = ntc_thermistor_remove,
715 	.id_table = ntc_thermistor_id,
716 };
717 
718 module_platform_driver(ntc_thermistor_driver);
719 
720 MODULE_DESCRIPTION("NTC Thermistor Driver");
721 MODULE_AUTHOR("MyungJoo Ham <myungjoo.ham@samsung.com>");
722 MODULE_LICENSE("GPL");
723 MODULE_ALIAS("platform:ntc-thermistor");
724