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 };
263 
264 #if defined(CONFIG_OF) && IS_ENABLED(CONFIG_IIO)
265 static int ntc_adc_iio_read(struct ntc_thermistor_platform_data *pdata)
266 {
267 	struct iio_channel *channel = pdata->chan;
268 	int raw, uv, ret;
269 
270 	ret = iio_read_channel_raw(channel, &raw);
271 	if (ret < 0) {
272 		pr_err("read channel() error: %d\n", ret);
273 		return ret;
274 	}
275 
276 	ret = iio_convert_raw_to_processed(channel, raw, &uv, 1000);
277 	if (ret < 0) {
278 		/* Assume 12 bit ADC with vref at pullup_uv */
279 		uv = (pdata->pullup_uv * (s64)raw) >> 12;
280 	}
281 
282 	return uv;
283 }
284 
285 static const struct of_device_id ntc_match[] = {
286 	{ .compatible = "murata,ncp15wb473",
287 		.data = &ntc_thermistor_id[0] },
288 	{ .compatible = "murata,ncp18wb473",
289 		.data = &ntc_thermistor_id[1] },
290 	{ .compatible = "murata,ncp21wb473",
291 		.data = &ntc_thermistor_id[2] },
292 	{ .compatible = "murata,ncp03wb473",
293 		.data = &ntc_thermistor_id[3] },
294 	{ .compatible = "murata,ncp15wl333",
295 		.data = &ntc_thermistor_id[4] },
296 	{ .compatible = "epcos,b57330v2103",
297 		.data = &ntc_thermistor_id[5]},
298 	{ .compatible = "murata,ncp03wf104",
299 		.data = &ntc_thermistor_id[6] },
300 	{ .compatible = "murata,ncp15xh103",
301 		.data = &ntc_thermistor_id[7] },
302 
303 	/* Usage of vendor name "ntc" is deprecated */
304 	{ .compatible = "ntc,ncp15wb473",
305 		.data = &ntc_thermistor_id[0] },
306 	{ .compatible = "ntc,ncp18wb473",
307 		.data = &ntc_thermistor_id[1] },
308 	{ .compatible = "ntc,ncp21wb473",
309 		.data = &ntc_thermistor_id[2] },
310 	{ .compatible = "ntc,ncp03wb473",
311 		.data = &ntc_thermistor_id[3] },
312 	{ .compatible = "ntc,ncp15wl333",
313 		.data = &ntc_thermistor_id[4] },
314 	{ },
315 };
316 MODULE_DEVICE_TABLE(of, ntc_match);
317 
318 static struct ntc_thermistor_platform_data *
319 ntc_thermistor_parse_dt(struct platform_device *pdev)
320 {
321 	struct iio_channel *chan;
322 	enum iio_chan_type type;
323 	struct device_node *np = pdev->dev.of_node;
324 	struct ntc_thermistor_platform_data *pdata;
325 	int ret;
326 
327 	if (!np)
328 		return NULL;
329 
330 	pdata = devm_kzalloc(&pdev->dev, sizeof(*pdata), GFP_KERNEL);
331 	if (!pdata)
332 		return ERR_PTR(-ENOMEM);
333 
334 	chan = iio_channel_get(&pdev->dev, NULL);
335 	if (IS_ERR(chan))
336 		return ERR_CAST(chan);
337 
338 	ret = iio_get_channel_type(chan, &type);
339 	if (ret < 0)
340 		return ERR_PTR(ret);
341 
342 	if (type != IIO_VOLTAGE)
343 		return ERR_PTR(-EINVAL);
344 
345 	if (of_property_read_u32(np, "pullup-uv", &pdata->pullup_uv))
346 		return ERR_PTR(-ENODEV);
347 	if (of_property_read_u32(np, "pullup-ohm", &pdata->pullup_ohm))
348 		return ERR_PTR(-ENODEV);
349 	if (of_property_read_u32(np, "pulldown-ohm", &pdata->pulldown_ohm))
350 		return ERR_PTR(-ENODEV);
351 
352 	if (of_find_property(np, "connected-positive", NULL))
353 		pdata->connect = NTC_CONNECTED_POSITIVE;
354 	else /* status change should be possible if not always on. */
355 		pdata->connect = NTC_CONNECTED_GROUND;
356 
357 	pdata->chan = chan;
358 	pdata->read_uv = ntc_adc_iio_read;
359 
360 	return pdata;
361 }
362 static void ntc_iio_channel_release(struct ntc_thermistor_platform_data *pdata)
363 {
364 	if (pdata->chan)
365 		iio_channel_release(pdata->chan);
366 }
367 #else
368 static struct ntc_thermistor_platform_data *
369 ntc_thermistor_parse_dt(struct platform_device *pdev)
370 {
371 	return NULL;
372 }
373 
374 #define ntc_match	NULL
375 
376 static void ntc_iio_channel_release(struct ntc_thermistor_platform_data *pdata)
377 { }
378 #endif
379 
380 static inline u64 div64_u64_safe(u64 dividend, u64 divisor)
381 {
382 	if (divisor == 0 && dividend == 0)
383 		return 0;
384 	if (divisor == 0)
385 		return UINT_MAX;
386 	return div64_u64(dividend, divisor);
387 }
388 
389 static int get_ohm_of_thermistor(struct ntc_data *data, unsigned int uv)
390 {
391 	struct ntc_thermistor_platform_data *pdata = data->pdata;
392 	u32 puv = pdata->pullup_uv;
393 	u64 n, puo, pdo;
394 	puo = pdata->pullup_ohm;
395 	pdo = pdata->pulldown_ohm;
396 
397 	if (uv == 0)
398 		return (pdata->connect == NTC_CONNECTED_POSITIVE) ?
399 			INT_MAX : 0;
400 	if (uv >= puv)
401 		return (pdata->connect == NTC_CONNECTED_POSITIVE) ?
402 			0 : INT_MAX;
403 
404 	if (pdata->connect == NTC_CONNECTED_POSITIVE && puo == 0)
405 		n = div_u64(pdo * (puv - uv), uv);
406 	else if (pdata->connect == NTC_CONNECTED_GROUND && pdo == 0)
407 		n = div_u64(puo * uv, puv - uv);
408 	else if (pdata->connect == NTC_CONNECTED_POSITIVE)
409 		n = div64_u64_safe(pdo * puo * (puv - uv),
410 				puo * uv - pdo * (puv - uv));
411 	else
412 		n = div64_u64_safe(pdo * puo * uv, pdo * (puv - uv) - puo * uv);
413 
414 	if (n > INT_MAX)
415 		n = INT_MAX;
416 	return n;
417 }
418 
419 static void lookup_comp(struct ntc_data *data, unsigned int ohm,
420 			int *i_low, int *i_high)
421 {
422 	int start, end, mid;
423 
424 	/*
425 	 * Handle special cases: Resistance is higher than or equal to
426 	 * resistance in first table entry, or resistance is lower or equal
427 	 * to resistance in last table entry.
428 	 * In these cases, return i_low == i_high, either pointing to the
429 	 * beginning or to the end of the table depending on the condition.
430 	 */
431 	if (ohm >= data->comp[0].ohm) {
432 		*i_low = 0;
433 		*i_high = 0;
434 		return;
435 	}
436 	if (ohm <= data->comp[data->n_comp - 1].ohm) {
437 		*i_low = data->n_comp - 1;
438 		*i_high = data->n_comp - 1;
439 		return;
440 	}
441 
442 	/* Do a binary search on compensation table */
443 	start = 0;
444 	end = data->n_comp;
445 	while (start < end) {
446 		mid = start + (end - start) / 2;
447 		/*
448 		 * start <= mid < end
449 		 * data->comp[start].ohm > ohm >= data->comp[end].ohm
450 		 *
451 		 * We could check for "ohm == data->comp[mid].ohm" here, but
452 		 * that is a quite unlikely condition, and we would have to
453 		 * check again after updating start. Check it at the end instead
454 		 * for simplicity.
455 		 */
456 		if (ohm >= data->comp[mid].ohm) {
457 			end = mid;
458 		} else {
459 			start = mid + 1;
460 			/*
461 			 * ohm >= data->comp[start].ohm might be true here,
462 			 * since we set start to mid + 1. In that case, we are
463 			 * done. We could keep going, but the condition is quite
464 			 * likely to occur, so it is worth checking for it.
465 			 */
466 			if (ohm >= data->comp[start].ohm)
467 				end = start;
468 		}
469 		/*
470 		 * start <= end
471 		 * data->comp[start].ohm >= ohm >= data->comp[end].ohm
472 		 */
473 	}
474 	/*
475 	 * start == end
476 	 * ohm >= data->comp[end].ohm
477 	 */
478 	*i_low = end;
479 	if (ohm == data->comp[end].ohm)
480 		*i_high = end;
481 	else
482 		*i_high = end - 1;
483 }
484 
485 static int get_temp_mc(struct ntc_data *data, unsigned int ohm)
486 {
487 	int low, high;
488 	int temp;
489 
490 	lookup_comp(data, ohm, &low, &high);
491 	if (low == high) {
492 		/* Unable to use linear approximation */
493 		temp = data->comp[low].temp_c * 1000;
494 	} else {
495 		temp = data->comp[low].temp_c * 1000 +
496 			((data->comp[high].temp_c - data->comp[low].temp_c) *
497 			 1000 * ((int)ohm - (int)data->comp[low].ohm)) /
498 			((int)data->comp[high].ohm - (int)data->comp[low].ohm);
499 	}
500 	return temp;
501 }
502 
503 static int ntc_thermistor_get_ohm(struct ntc_data *data)
504 {
505 	int read_uv;
506 
507 	if (data->pdata->read_ohm)
508 		return data->pdata->read_ohm();
509 
510 	if (data->pdata->read_uv) {
511 		read_uv = data->pdata->read_uv(data->pdata);
512 		if (read_uv < 0)
513 			return read_uv;
514 		return get_ohm_of_thermistor(data, read_uv);
515 	}
516 	return -EINVAL;
517 }
518 
519 static int ntc_read_temp(void *dev, int *temp)
520 {
521 	struct ntc_data *data = dev_get_drvdata(dev);
522 	int ohm;
523 
524 	ohm = ntc_thermistor_get_ohm(data);
525 	if (ohm < 0)
526 		return ohm;
527 
528 	*temp = get_temp_mc(data, ohm);
529 
530 	return 0;
531 }
532 
533 static ssize_t ntc_show_name(struct device *dev,
534 		struct device_attribute *attr, char *buf)
535 {
536 	struct ntc_data *data = dev_get_drvdata(dev);
537 
538 	return sprintf(buf, "%s\n", data->name);
539 }
540 
541 static ssize_t ntc_show_type(struct device *dev,
542 		struct device_attribute *attr, char *buf)
543 {
544 	return sprintf(buf, "4\n");
545 }
546 
547 static ssize_t ntc_show_temp(struct device *dev,
548 		struct device_attribute *attr, char *buf)
549 {
550 	struct ntc_data *data = dev_get_drvdata(dev);
551 	int ohm;
552 
553 	ohm = ntc_thermistor_get_ohm(data);
554 	if (ohm < 0)
555 		return ohm;
556 
557 	return sprintf(buf, "%d\n", get_temp_mc(data, ohm));
558 }
559 
560 static SENSOR_DEVICE_ATTR(temp1_type, S_IRUGO, ntc_show_type, NULL, 0);
561 static SENSOR_DEVICE_ATTR(temp1_input, S_IRUGO, ntc_show_temp, NULL, 0);
562 static DEVICE_ATTR(name, S_IRUGO, ntc_show_name, NULL);
563 
564 static struct attribute *ntc_attributes[] = {
565 	&dev_attr_name.attr,
566 	&sensor_dev_attr_temp1_type.dev_attr.attr,
567 	&sensor_dev_attr_temp1_input.dev_attr.attr,
568 	NULL,
569 };
570 
571 static const struct attribute_group ntc_attr_group = {
572 	.attrs = ntc_attributes,
573 };
574 
575 static const struct thermal_zone_of_device_ops ntc_of_thermal_ops = {
576 	.get_temp = ntc_read_temp,
577 };
578 
579 static int ntc_thermistor_probe(struct platform_device *pdev)
580 {
581 	struct thermal_zone_device *tz;
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 	tz = devm_thermal_zone_of_sensor_register(data->dev, 0, data->dev,
681 						  &ntc_of_thermal_ops);
682 	if (IS_ERR(tz))
683 		dev_dbg(&pdev->dev, "Failed to register to thermal fw.\n");
684 
685 	return 0;
686 err_after_sysfs:
687 	sysfs_remove_group(&data->dev->kobj, &ntc_attr_group);
688 	ntc_iio_channel_release(pdata);
689 	return ret;
690 }
691 
692 static int ntc_thermistor_remove(struct platform_device *pdev)
693 {
694 	struct ntc_data *data = platform_get_drvdata(pdev);
695 	struct ntc_thermistor_platform_data *pdata = data->pdata;
696 
697 	hwmon_device_unregister(data->hwmon_dev);
698 	sysfs_remove_group(&data->dev->kobj, &ntc_attr_group);
699 	ntc_iio_channel_release(pdata);
700 
701 	return 0;
702 }
703 
704 static struct platform_driver ntc_thermistor_driver = {
705 	.driver = {
706 		.name = "ntc-thermistor",
707 		.of_match_table = of_match_ptr(ntc_match),
708 	},
709 	.probe = ntc_thermistor_probe,
710 	.remove = ntc_thermistor_remove,
711 	.id_table = ntc_thermistor_id,
712 };
713 
714 module_platform_driver(ntc_thermistor_driver);
715 
716 MODULE_DESCRIPTION("NTC Thermistor Driver");
717 MODULE_AUTHOR("MyungJoo Ham <myungjoo.ham@samsung.com>");
718 MODULE_LICENSE("GPL");
719 MODULE_ALIAS("platform:ntc-thermistor");
720