hwmon: (nct6775) Drop read/write lock
[linux-2.6-block.git] / drivers / hwmon / ntc_thermistor.c
CommitLineData
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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>
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29#include <linux/of.h>
30#include <linux/of_device.h>
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31
32#include <linux/platform_data/ntc_thermistor.h>
33
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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
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39#include <linux/hwmon.h>
40#include <linux/hwmon-sysfs.h>
41
42struct ntc_compensation {
43 int temp_C;
44 unsigned int ohm;
45};
46
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47static const struct platform_device_id ntc_thermistor_id[] = {
48 { "ncp15wb473", TYPE_NCPXXWB473 },
49 { "ncp18wb473", TYPE_NCPXXWB473 },
50 { "ncp21wb473", TYPE_NCPXXWB473 },
51 { "ncp03wb473", TYPE_NCPXXWB473 },
52 { "ncp15wl333", TYPE_NCPXXWL333 },
53 { },
54};
55
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56/*
57 * A compensation table should be sorted by the values of .ohm
58 * in descending order.
59 * The following compensation tables are from the specification of Murata NTC
60 * Thermistors Datasheet
61 */
4626dcff 62static const struct ntc_compensation ncpXXwb473[] = {
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63 { .temp_C = -40, .ohm = 1747920 },
64 { .temp_C = -35, .ohm = 1245428 },
65 { .temp_C = -30, .ohm = 898485 },
66 { .temp_C = -25, .ohm = 655802 },
67 { .temp_C = -20, .ohm = 483954 },
68 { .temp_C = -15, .ohm = 360850 },
69 { .temp_C = -10, .ohm = 271697 },
70 { .temp_C = -5, .ohm = 206463 },
71 { .temp_C = 0, .ohm = 158214 },
72 { .temp_C = 5, .ohm = 122259 },
73 { .temp_C = 10, .ohm = 95227 },
74 { .temp_C = 15, .ohm = 74730 },
75 { .temp_C = 20, .ohm = 59065 },
76 { .temp_C = 25, .ohm = 47000 },
77 { .temp_C = 30, .ohm = 37643 },
78 { .temp_C = 35, .ohm = 30334 },
79 { .temp_C = 40, .ohm = 24591 },
80 { .temp_C = 45, .ohm = 20048 },
81 { .temp_C = 50, .ohm = 16433 },
82 { .temp_C = 55, .ohm = 13539 },
83 { .temp_C = 60, .ohm = 11209 },
84 { .temp_C = 65, .ohm = 9328 },
85 { .temp_C = 70, .ohm = 7798 },
86 { .temp_C = 75, .ohm = 6544 },
87 { .temp_C = 80, .ohm = 5518 },
88 { .temp_C = 85, .ohm = 4674 },
89 { .temp_C = 90, .ohm = 3972 },
90 { .temp_C = 95, .ohm = 3388 },
91 { .temp_C = 100, .ohm = 2902 },
92 { .temp_C = 105, .ohm = 2494 },
93 { .temp_C = 110, .ohm = 2150 },
94 { .temp_C = 115, .ohm = 1860 },
95 { .temp_C = 120, .ohm = 1615 },
96 { .temp_C = 125, .ohm = 1406 },
97};
4626dcff 98static const struct ntc_compensation ncpXXwl333[] = {
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99 { .temp_C = -40, .ohm = 1610154 },
100 { .temp_C = -35, .ohm = 1130850 },
101 { .temp_C = -30, .ohm = 802609 },
102 { .temp_C = -25, .ohm = 575385 },
103 { .temp_C = -20, .ohm = 416464 },
104 { .temp_C = -15, .ohm = 304219 },
105 { .temp_C = -10, .ohm = 224193 },
106 { .temp_C = -5, .ohm = 166623 },
107 { .temp_C = 0, .ohm = 124850 },
108 { .temp_C = 5, .ohm = 94287 },
109 { .temp_C = 10, .ohm = 71747 },
110 { .temp_C = 15, .ohm = 54996 },
111 { .temp_C = 20, .ohm = 42455 },
112 { .temp_C = 25, .ohm = 33000 },
113 { .temp_C = 30, .ohm = 25822 },
114 { .temp_C = 35, .ohm = 20335 },
115 { .temp_C = 40, .ohm = 16115 },
116 { .temp_C = 45, .ohm = 12849 },
117 { .temp_C = 50, .ohm = 10306 },
118 { .temp_C = 55, .ohm = 8314 },
119 { .temp_C = 60, .ohm = 6746 },
120 { .temp_C = 65, .ohm = 5503 },
121 { .temp_C = 70, .ohm = 4513 },
122 { .temp_C = 75, .ohm = 3721 },
123 { .temp_C = 80, .ohm = 3084 },
124 { .temp_C = 85, .ohm = 2569 },
125 { .temp_C = 90, .ohm = 2151 },
126 { .temp_C = 95, .ohm = 1809 },
127 { .temp_C = 100, .ohm = 1529 },
128 { .temp_C = 105, .ohm = 1299 },
129 { .temp_C = 110, .ohm = 1108 },
130 { .temp_C = 115, .ohm = 949 },
131 { .temp_C = 120, .ohm = 817 },
132 { .temp_C = 125, .ohm = 707 },
133};
134
135struct ntc_data {
136 struct device *hwmon_dev;
137 struct ntc_thermistor_platform_data *pdata;
138 const struct ntc_compensation *comp;
139 struct device *dev;
140 int n_comp;
141 char name[PLATFORM_NAME_SIZE];
142};
143
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144#ifdef CONFIG_OF
145static int ntc_adc_iio_read(struct ntc_thermistor_platform_data *pdata)
146{
147 struct iio_channel *channel = pdata->chan;
148 unsigned int result;
149 int val, ret;
150
151 ret = iio_read_channel_raw(channel, &val);
152 if (ret < 0) {
153 pr_err("read channel() error: %d\n", ret);
154 return ret;
155 }
156
157 /* unit: mV */
158 result = pdata->pullup_uV * val;
159 result >>= 12;
160
161 return result;
162}
163
164static const struct of_device_id ntc_match[] = {
165 { .compatible = "ntc,ncp15wb473",
166 .data = &ntc_thermistor_id[TYPE_NCPXXWB473] },
167 { .compatible = "ntc,ncp18wb473",
168 .data = &ntc_thermistor_id[TYPE_NCPXXWB473] },
169 { .compatible = "ntc,ncp21wb473",
170 .data = &ntc_thermistor_id[TYPE_NCPXXWB473] },
171 { .compatible = "ntc,ncp03wb473",
172 .data = &ntc_thermistor_id[TYPE_NCPXXWB473] },
173 { .compatible = "ntc,ncp15wl333",
174 .data = &ntc_thermistor_id[TYPE_NCPXXWL333] },
175 { },
176};
177MODULE_DEVICE_TABLE(of, ntc_match);
178
179static struct ntc_thermistor_platform_data *
180ntc_thermistor_parse_dt(struct platform_device *pdev)
181{
182 struct iio_channel *chan;
183 struct device_node *np = pdev->dev.of_node;
184 struct ntc_thermistor_platform_data *pdata;
185
186 if (!np)
187 return NULL;
188
189 pdata = devm_kzalloc(&pdev->dev, sizeof(*pdata), GFP_KERNEL);
190 if (!pdata)
191 return ERR_PTR(-ENOMEM);
192
193 chan = iio_channel_get(&pdev->dev, NULL);
194 if (IS_ERR(chan))
195 return ERR_CAST(chan);
196
197 if (of_property_read_u32(np, "pullup-uv", &pdata->pullup_uV))
198 return ERR_PTR(-ENODEV);
199 if (of_property_read_u32(np, "pullup-ohm", &pdata->pullup_ohm))
200 return ERR_PTR(-ENODEV);
201 if (of_property_read_u32(np, "pulldown-ohm", &pdata->pulldown_ohm))
202 return ERR_PTR(-ENODEV);
203
204 if (of_find_property(np, "connected-positive", NULL))
205 pdata->connect = NTC_CONNECTED_POSITIVE;
206 else /* status change should be possible if not always on. */
207 pdata->connect = NTC_CONNECTED_GROUND;
208
209 pdata->chan = chan;
210 pdata->read_uV = ntc_adc_iio_read;
211
212 return pdata;
213}
214static void ntc_iio_channel_release(struct ntc_thermistor_platform_data *pdata)
215{
216 if (pdata->chan)
217 iio_channel_release(pdata->chan);
218}
219#else
220static struct ntc_thermistor_platform_data *
221ntc_thermistor_parse_dt(struct platform_device *pdev)
222{
223 return NULL;
224}
225
226static void ntc_iio_channel_release(struct ntc_thermistor_platform_data *pdata)
227{ }
228#endif
229
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230static inline u64 div64_u64_safe(u64 dividend, u64 divisor)
231{
232 if (divisor == 0 && dividend == 0)
233 return 0;
234 if (divisor == 0)
235 return UINT_MAX;
236 return div64_u64(dividend, divisor);
237}
238
dbe43a62 239static int get_ohm_of_thermistor(struct ntc_data *data, unsigned int uV)
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240{
241 struct ntc_thermistor_platform_data *pdata = data->pdata;
242 u64 mV = uV / 1000;
243 u64 pmV = pdata->pullup_uV / 1000;
244 u64 N, puO, pdO;
245 puO = pdata->pullup_ohm;
246 pdO = pdata->pulldown_ohm;
247
248 if (mV == 0) {
249 if (pdata->connect == NTC_CONNECTED_POSITIVE)
dbe43a62 250 return INT_MAX;
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251 return 0;
252 }
253 if (mV >= pmV)
254 return (pdata->connect == NTC_CONNECTED_POSITIVE) ?
dbe43a62 255 0 : INT_MAX;
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256
257 if (pdata->connect == NTC_CONNECTED_POSITIVE && puO == 0)
258 N = div64_u64_safe(pdO * (pmV - mV), mV);
259 else if (pdata->connect == NTC_CONNECTED_GROUND && pdO == 0)
260 N = div64_u64_safe(puO * mV, pmV - mV);
261 else if (pdata->connect == NTC_CONNECTED_POSITIVE)
262 N = div64_u64_safe(pdO * puO * (pmV - mV),
263 puO * mV - pdO * (pmV - mV));
264 else
265 N = div64_u64_safe(pdO * puO * mV, pdO * (pmV - mV) - puO * mV);
266
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267 if (N > INT_MAX)
268 N = INT_MAX;
269 return N;
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270}
271
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272static void lookup_comp(struct ntc_data *data, unsigned int ohm,
273 int *i_low, int *i_high)
f22aaaa7 274{
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275 int start, end, mid;
276
277 /*
278 * Handle special cases: Resistance is higher than or equal to
279 * resistance in first table entry, or resistance is lower or equal
280 * to resistance in last table entry.
281 * In these cases, return i_low == i_high, either pointing to the
282 * beginning or to the end of the table depending on the condition.
283 */
284 if (ohm >= data->comp[0].ohm) {
285 *i_low = 0;
286 *i_high = 0;
287 return;
288 }
289 if (ohm <= data->comp[data->n_comp - 1].ohm) {
290 *i_low = data->n_comp - 1;
291 *i_high = data->n_comp - 1;
292 return;
293 }
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294
295 /* Do a binary search on compensation table */
296 start = 0;
297 end = data->n_comp;
dbe43a62 298 while (start < end) {
f22aaaa7 299 mid = start + (end - start) / 2;
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300 /*
301 * start <= mid < end
302 * data->comp[start].ohm > ohm >= data->comp[end].ohm
303 *
304 * We could check for "ohm == data->comp[mid].ohm" here, but
305 * that is a quite unlikely condition, and we would have to
306 * check again after updating start. Check it at the end instead
307 * for simplicity.
308 */
309 if (ohm >= data->comp[mid].ohm) {
f22aaaa7 310 end = mid;
f22aaaa7 311 } else {
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312 start = mid + 1;
313 /*
314 * ohm >= data->comp[start].ohm might be true here,
315 * since we set start to mid + 1. In that case, we are
316 * done. We could keep going, but the condition is quite
317 * likely to occur, so it is worth checking for it.
318 */
319 if (ohm >= data->comp[start].ohm)
320 end = start;
f22aaaa7 321 }
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322 /*
323 * start <= end
324 * data->comp[start].ohm >= ohm >= data->comp[end].ohm
325 */
f22aaaa7 326 }
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327 /*
328 * start == end
329 * ohm >= data->comp[end].ohm
330 */
331 *i_low = end;
332 if (ohm == data->comp[end].ohm)
333 *i_high = end;
334 else
335 *i_high = end - 1;
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336}
337
dbe43a62 338static int get_temp_mC(struct ntc_data *data, unsigned int ohm)
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339{
340 int low, high;
dbe43a62 341 int temp;
f22aaaa7 342
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343 lookup_comp(data, ohm, &low, &high);
344 if (low == high) {
f22aaaa7 345 /* Unable to use linear approximation */
dbe43a62 346 temp = data->comp[low].temp_C * 1000;
f22aaaa7 347 } else {
dbe43a62 348 temp = data->comp[low].temp_C * 1000 +
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349 ((data->comp[high].temp_C - data->comp[low].temp_C) *
350 1000 * ((int)ohm - (int)data->comp[low].ohm)) /
351 ((int)data->comp[high].ohm - (int)data->comp[low].ohm);
352 }
dbe43a62 353 return temp;
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354}
355
dbe43a62 356static int ntc_thermistor_get_ohm(struct ntc_data *data)
f22aaaa7 357{
dbe43a62 358 int read_uV;
f22aaaa7 359
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360 if (data->pdata->read_ohm)
361 return data->pdata->read_ohm();
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362
363 if (data->pdata->read_uV) {
9e8269de 364 read_uV = data->pdata->read_uV(data->pdata);
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365 if (read_uV < 0)
366 return read_uV;
dbe43a62 367 return get_ohm_of_thermistor(data, read_uV);
f22aaaa7 368 }
dbe43a62 369 return -EINVAL;
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370}
371
372static ssize_t ntc_show_name(struct device *dev,
373 struct device_attribute *attr, char *buf)
374{
375 struct ntc_data *data = dev_get_drvdata(dev);
376
377 return sprintf(buf, "%s\n", data->name);
378}
379
380static ssize_t ntc_show_type(struct device *dev,
381 struct device_attribute *attr, char *buf)
382{
383 return sprintf(buf, "4\n");
384}
385
386static ssize_t ntc_show_temp(struct device *dev,
387 struct device_attribute *attr, char *buf)
388{
389 struct ntc_data *data = dev_get_drvdata(dev);
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390 int ohm;
391
392 ohm = ntc_thermistor_get_ohm(data);
393 if (ohm < 0)
394 return ohm;
f22aaaa7 395
dbe43a62 396 return sprintf(buf, "%d\n", get_temp_mC(data, ohm));
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397}
398
399static SENSOR_DEVICE_ATTR(temp1_type, S_IRUGO, ntc_show_type, NULL, 0);
400static SENSOR_DEVICE_ATTR(temp1_input, S_IRUGO, ntc_show_temp, NULL, 0);
401static DEVICE_ATTR(name, S_IRUGO, ntc_show_name, NULL);
402
403static struct attribute *ntc_attributes[] = {
404 &dev_attr_name.attr,
405 &sensor_dev_attr_temp1_type.dev_attr.attr,
406 &sensor_dev_attr_temp1_input.dev_attr.attr,
407 NULL,
408};
409
410static const struct attribute_group ntc_attr_group = {
411 .attrs = ntc_attributes,
412};
413
6c931ae1 414static int ntc_thermistor_probe(struct platform_device *pdev)
f22aaaa7 415{
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416 const struct of_device_id *of_id =
417 of_match_device(of_match_ptr(ntc_match), &pdev->dev);
418 const struct platform_device_id *pdev_id;
419 struct ntc_thermistor_platform_data *pdata;
f22aaaa7 420 struct ntc_data *data;
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421 int ret;
422
423 pdata = ntc_thermistor_parse_dt(pdev);
424 if (IS_ERR(pdata))
425 return PTR_ERR(pdata);
426 else if (pdata == NULL)
427 pdata = pdev->dev.platform_data;
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428
429 if (!pdata) {
430 dev_err(&pdev->dev, "No platform init data supplied.\n");
431 return -ENODEV;
432 }
433
434 /* Either one of the two is required. */
435 if (!pdata->read_uV && !pdata->read_ohm) {
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436 dev_err(&pdev->dev,
437 "Both read_uV and read_ohm missing. Need either one of the two.\n");
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438 return -EINVAL;
439 }
440
441 if (pdata->read_uV && pdata->read_ohm) {
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442 dev_warn(&pdev->dev,
443 "Only one of read_uV and read_ohm is needed; ignoring read_uV.\n");
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444 pdata->read_uV = NULL;
445 }
446
447 if (pdata->read_uV && (pdata->pullup_uV == 0 ||
448 (pdata->pullup_ohm == 0 && pdata->connect ==
449 NTC_CONNECTED_GROUND) ||
450 (pdata->pulldown_ohm == 0 && pdata->connect ==
451 NTC_CONNECTED_POSITIVE) ||
452 (pdata->connect != NTC_CONNECTED_POSITIVE &&
453 pdata->connect != NTC_CONNECTED_GROUND))) {
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454 dev_err(&pdev->dev,
455 "Required data to use read_uV not supplied.\n");
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456 return -EINVAL;
457 }
458
41141e64 459 data = devm_kzalloc(&pdev->dev, sizeof(struct ntc_data), GFP_KERNEL);
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460 if (!data)
461 return -ENOMEM;
462
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463 pdev_id = of_id ? of_id->data : platform_get_device_id(pdev);
464
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465 data->dev = &pdev->dev;
466 data->pdata = pdata;
9e8269de 467 strlcpy(data->name, pdev_id->name, sizeof(data->name));
f22aaaa7 468
9e8269de 469 switch (pdev_id->driver_data) {
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470 case TYPE_NCPXXWB473:
471 data->comp = ncpXXwb473;
472 data->n_comp = ARRAY_SIZE(ncpXXwb473);
473 break;
474 case TYPE_NCPXXWL333:
475 data->comp = ncpXXwl333;
476 data->n_comp = ARRAY_SIZE(ncpXXwl333);
477 break;
478 default:
479 dev_err(&pdev->dev, "Unknown device type: %lu(%s)\n",
9e8269de 480 pdev_id->driver_data, pdev_id->name);
41141e64 481 return -EINVAL;
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482 }
483
484 platform_set_drvdata(pdev, data);
485
486 ret = sysfs_create_group(&data->dev->kobj, &ntc_attr_group);
487 if (ret) {
488 dev_err(data->dev, "unable to create sysfs files\n");
41141e64 489 return ret;
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490 }
491
492 data->hwmon_dev = hwmon_device_register(data->dev);
425d2476 493 if (IS_ERR(data->hwmon_dev)) {
f22aaaa7 494 dev_err(data->dev, "unable to register as hwmon device.\n");
425d2476 495 ret = PTR_ERR(data->hwmon_dev);
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496 goto err_after_sysfs;
497 }
498
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499 dev_info(&pdev->dev, "Thermistor type: %s successfully probed.\n",
500 pdev->name);
501
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502 return 0;
503err_after_sysfs:
504 sysfs_remove_group(&data->dev->kobj, &ntc_attr_group);
9e8269de 505 ntc_iio_channel_release(pdata);
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506 return ret;
507}
508
281dfd0b 509static int ntc_thermistor_remove(struct platform_device *pdev)
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510{
511 struct ntc_data *data = platform_get_drvdata(pdev);
9e8269de 512 struct ntc_thermistor_platform_data *pdata = data->pdata;
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513
514 hwmon_device_unregister(data->hwmon_dev);
515 sysfs_remove_group(&data->dev->kobj, &ntc_attr_group);
9e8269de 516 ntc_iio_channel_release(pdata);
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517 platform_set_drvdata(pdev, NULL);
518
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519 return 0;
520}
521
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522static struct platform_driver ntc_thermistor_driver = {
523 .driver = {
524 .name = "ntc-thermistor",
525 .owner = THIS_MODULE,
9e8269de 526 .of_match_table = of_match_ptr(ntc_match),
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527 },
528 .probe = ntc_thermistor_probe,
9e5e9b7a 529 .remove = ntc_thermistor_remove,
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530 .id_table = ntc_thermistor_id,
531};
532
25a236a5 533module_platform_driver(ntc_thermistor_driver);
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534
535MODULE_DESCRIPTION("NTC Thermistor Driver");
536MODULE_AUTHOR("MyungJoo Ham <myungjoo.ham@samsung.com>");
537MODULE_LICENSE("GPL");
538MODULE_ALIAS("platform:ntc-thermistor");