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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
42struct ntc_compensation {
43 int temp_c;
44 unsigned int ohm;
45};
46
47
48static const struct platform_device_id ntc_thermistor_id[] = {
49 { "ncp15wb473", TYPE_NCPXXWB473 },
50 { "ncp18wb473", TYPE_NCPXXWB473 },
51 { "ncp21wb473", TYPE_NCPXXWB473 },
52 { "ncp03wb473", TYPE_NCPXXWB473 },
53 { "ncp15wl333", TYPE_NCPXXWL333 },
54 { },
55};
56
57
58
59
60
61
62
63static const struct ntc_compensation ncpXXwb473[] = {
64 { .temp_c = -40, .ohm = 1747920 },
65 { .temp_c = -35, .ohm = 1245428 },
66 { .temp_c = -30, .ohm = 898485 },
67 { .temp_c = -25, .ohm = 655802 },
68 { .temp_c = -20, .ohm = 483954 },
69 { .temp_c = -15, .ohm = 360850 },
70 { .temp_c = -10, .ohm = 271697 },
71 { .temp_c = -5, .ohm = 206463 },
72 { .temp_c = 0, .ohm = 158214 },
73 { .temp_c = 5, .ohm = 122259 },
74 { .temp_c = 10, .ohm = 95227 },
75 { .temp_c = 15, .ohm = 74730 },
76 { .temp_c = 20, .ohm = 59065 },
77 { .temp_c = 25, .ohm = 47000 },
78 { .temp_c = 30, .ohm = 37643 },
79 { .temp_c = 35, .ohm = 30334 },
80 { .temp_c = 40, .ohm = 24591 },
81 { .temp_c = 45, .ohm = 20048 },
82 { .temp_c = 50, .ohm = 16433 },
83 { .temp_c = 55, .ohm = 13539 },
84 { .temp_c = 60, .ohm = 11209 },
85 { .temp_c = 65, .ohm = 9328 },
86 { .temp_c = 70, .ohm = 7798 },
87 { .temp_c = 75, .ohm = 6544 },
88 { .temp_c = 80, .ohm = 5518 },
89 { .temp_c = 85, .ohm = 4674 },
90 { .temp_c = 90, .ohm = 3972 },
91 { .temp_c = 95, .ohm = 3388 },
92 { .temp_c = 100, .ohm = 2902 },
93 { .temp_c = 105, .ohm = 2494 },
94 { .temp_c = 110, .ohm = 2150 },
95 { .temp_c = 115, .ohm = 1860 },
96 { .temp_c = 120, .ohm = 1615 },
97 { .temp_c = 125, .ohm = 1406 },
98};
99static const struct ntc_compensation ncpXXwl333[] = {
100 { .temp_c = -40, .ohm = 1610154 },
101 { .temp_c = -35, .ohm = 1130850 },
102 { .temp_c = -30, .ohm = 802609 },
103 { .temp_c = -25, .ohm = 575385 },
104 { .temp_c = -20, .ohm = 416464 },
105 { .temp_c = -15, .ohm = 304219 },
106 { .temp_c = -10, .ohm = 224193 },
107 { .temp_c = -5, .ohm = 166623 },
108 { .temp_c = 0, .ohm = 124850 },
109 { .temp_c = 5, .ohm = 94287 },
110 { .temp_c = 10, .ohm = 71747 },
111 { .temp_c = 15, .ohm = 54996 },
112 { .temp_c = 20, .ohm = 42455 },
113 { .temp_c = 25, .ohm = 33000 },
114 { .temp_c = 30, .ohm = 25822 },
115 { .temp_c = 35, .ohm = 20335 },
116 { .temp_c = 40, .ohm = 16115 },
117 { .temp_c = 45, .ohm = 12849 },
118 { .temp_c = 50, .ohm = 10306 },
119 { .temp_c = 55, .ohm = 8314 },
120 { .temp_c = 60, .ohm = 6746 },
121 { .temp_c = 65, .ohm = 5503 },
122 { .temp_c = 70, .ohm = 4513 },
123 { .temp_c = 75, .ohm = 3721 },
124 { .temp_c = 80, .ohm = 3084 },
125 { .temp_c = 85, .ohm = 2569 },
126 { .temp_c = 90, .ohm = 2151 },
127 { .temp_c = 95, .ohm = 1809 },
128 { .temp_c = 100, .ohm = 1529 },
129 { .temp_c = 105, .ohm = 1299 },
130 { .temp_c = 110, .ohm = 1108 },
131 { .temp_c = 115, .ohm = 949 },
132 { .temp_c = 120, .ohm = 817 },
133 { .temp_c = 125, .ohm = 707 },
134};
135
136struct ntc_data {
137 struct device *hwmon_dev;
138 struct ntc_thermistor_platform_data *pdata;
139 const struct ntc_compensation *comp;
140 struct device *dev;
141 int n_comp;
142 char name[PLATFORM_NAME_SIZE];
143};
144
145#if defined(CONFIG_OF) && IS_ENABLED(CONFIG_IIO)
146static int ntc_adc_iio_read(struct ntc_thermistor_platform_data *pdata)
147{
148 struct iio_channel *channel = pdata->chan;
149 s64 result;
150 int val, ret;
151
152 ret = iio_read_channel_raw(channel, &val);
153 if (ret < 0) {
154 pr_err("read channel() error: %d\n", ret);
155 return ret;
156 }
157
158
159 result = pdata->pullup_uv * (s64) val;
160 result >>= 12;
161
162 return (int)result;
163}
164
165static const struct of_device_id ntc_match[] = {
166 { .compatible = "ntc,ncp15wb473",
167 .data = &ntc_thermistor_id[0] },
168 { .compatible = "ntc,ncp18wb473",
169 .data = &ntc_thermistor_id[1] },
170 { .compatible = "ntc,ncp21wb473",
171 .data = &ntc_thermistor_id[2] },
172 { .compatible = "ntc,ncp03wb473",
173 .data = &ntc_thermistor_id[3] },
174 { .compatible = "ntc,ncp15wl333",
175 .data = &ntc_thermistor_id[4] },
176 { },
177};
178MODULE_DEVICE_TABLE(of, ntc_match);
179
180static struct ntc_thermistor_platform_data *
181ntc_thermistor_parse_dt(struct platform_device *pdev)
182{
183 struct iio_channel *chan;
184 enum iio_chan_type type;
185 struct device_node *np = pdev->dev.of_node;
186 struct ntc_thermistor_platform_data *pdata;
187 int ret;
188
189 if (!np)
190 return NULL;
191
192 pdata = devm_kzalloc(&pdev->dev, sizeof(*pdata), GFP_KERNEL);
193 if (!pdata)
194 return ERR_PTR(-ENOMEM);
195
196 chan = iio_channel_get(&pdev->dev, NULL);
197 if (IS_ERR(chan))
198 return ERR_CAST(chan);
199
200 ret = iio_get_channel_type(chan, &type);
201 if (ret < 0)
202 return ERR_PTR(ret);
203
204 if (type != IIO_VOLTAGE)
205 return ERR_PTR(-EINVAL);
206
207 if (of_property_read_u32(np, "pullup-uv", &pdata->pullup_uv))
208 return ERR_PTR(-ENODEV);
209 if (of_property_read_u32(np, "pullup-ohm", &pdata->pullup_ohm))
210 return ERR_PTR(-ENODEV);
211 if (of_property_read_u32(np, "pulldown-ohm", &pdata->pulldown_ohm))
212 return ERR_PTR(-ENODEV);
213
214 if (of_find_property(np, "connected-positive", NULL))
215 pdata->connect = NTC_CONNECTED_POSITIVE;
216 else
217 pdata->connect = NTC_CONNECTED_GROUND;
218
219 pdata->chan = chan;
220 pdata->read_uv = ntc_adc_iio_read;
221
222 return pdata;
223}
224static void ntc_iio_channel_release(struct ntc_thermistor_platform_data *pdata)
225{
226 if (pdata->chan)
227 iio_channel_release(pdata->chan);
228}
229#else
230static struct ntc_thermistor_platform_data *
231ntc_thermistor_parse_dt(struct platform_device *pdev)
232{
233 return NULL;
234}
235
236#define ntc_match NULL
237
238static void ntc_iio_channel_release(struct ntc_thermistor_platform_data *pdata)
239{ }
240#endif
241
242static inline u64 div64_u64_safe(u64 dividend, u64 divisor)
243{
244 if (divisor == 0 && dividend == 0)
245 return 0;
246 if (divisor == 0)
247 return UINT_MAX;
248 return div64_u64(dividend, divisor);
249}
250
251static int get_ohm_of_thermistor(struct ntc_data *data, unsigned int uv)
252{
253 struct ntc_thermistor_platform_data *pdata = data->pdata;
254 u64 mv = uv / 1000;
255 u64 pmv = pdata->pullup_uv / 1000;
256 u64 n, puo, pdo;
257 puo = pdata->pullup_ohm;
258 pdo = pdata->pulldown_ohm;
259
260 if (mv == 0) {
261 if (pdata->connect == NTC_CONNECTED_POSITIVE)
262 return INT_MAX;
263 return 0;
264 }
265 if (mv >= pmv)
266 return (pdata->connect == NTC_CONNECTED_POSITIVE) ?
267 0 : INT_MAX;
268
269 if (pdata->connect == NTC_CONNECTED_POSITIVE && puo == 0)
270 n = div64_u64_safe(pdo * (pmv - mv), mv);
271 else if (pdata->connect == NTC_CONNECTED_GROUND && pdo == 0)
272 n = div64_u64_safe(puo * mv, pmv - mv);
273 else if (pdata->connect == NTC_CONNECTED_POSITIVE)
274 n = div64_u64_safe(pdo * puo * (pmv - mv),
275 puo * mv - pdo * (pmv - mv));
276 else
277 n = div64_u64_safe(pdo * puo * mv, pdo * (pmv - mv) - puo * mv);
278
279 if (n > INT_MAX)
280 n = INT_MAX;
281 return n;
282}
283
284static void lookup_comp(struct ntc_data *data, unsigned int ohm,
285 int *i_low, int *i_high)
286{
287 int start, end, mid;
288
289
290
291
292
293
294
295
296 if (ohm >= data->comp[0].ohm) {
297 *i_low = 0;
298 *i_high = 0;
299 return;
300 }
301 if (ohm <= data->comp[data->n_comp - 1].ohm) {
302 *i_low = data->n_comp - 1;
303 *i_high = data->n_comp - 1;
304 return;
305 }
306
307
308 start = 0;
309 end = data->n_comp;
310 while (start < end) {
311 mid = start + (end - start) / 2;
312
313
314
315
316
317
318
319
320
321 if (ohm >= data->comp[mid].ohm) {
322 end = mid;
323 } else {
324 start = mid + 1;
325
326
327
328
329
330
331 if (ohm >= data->comp[start].ohm)
332 end = start;
333 }
334
335
336
337
338 }
339
340
341
342
343 *i_low = end;
344 if (ohm == data->comp[end].ohm)
345 *i_high = end;
346 else
347 *i_high = end - 1;
348}
349
350static int get_temp_mc(struct ntc_data *data, unsigned int ohm)
351{
352 int low, high;
353 int temp;
354
355 lookup_comp(data, ohm, &low, &high);
356 if (low == high) {
357
358 temp = data->comp[low].temp_c * 1000;
359 } else {
360 temp = data->comp[low].temp_c * 1000 +
361 ((data->comp[high].temp_c - data->comp[low].temp_c) *
362 1000 * ((int)ohm - (int)data->comp[low].ohm)) /
363 ((int)data->comp[high].ohm - (int)data->comp[low].ohm);
364 }
365 return temp;
366}
367
368static int ntc_thermistor_get_ohm(struct ntc_data *data)
369{
370 int read_uv;
371
372 if (data->pdata->read_ohm)
373 return data->pdata->read_ohm();
374
375 if (data->pdata->read_uv) {
376 read_uv = data->pdata->read_uv(data->pdata);
377 if (read_uv < 0)
378 return read_uv;
379 return get_ohm_of_thermistor(data, read_uv);
380 }
381 return -EINVAL;
382}
383
384static ssize_t ntc_show_name(struct device *dev,
385 struct device_attribute *attr, char *buf)
386{
387 struct ntc_data *data = dev_get_drvdata(dev);
388
389 return sprintf(buf, "%s\n", data->name);
390}
391
392static ssize_t ntc_show_type(struct device *dev,
393 struct device_attribute *attr, char *buf)
394{
395 return sprintf(buf, "4\n");
396}
397
398static ssize_t ntc_show_temp(struct device *dev,
399 struct device_attribute *attr, char *buf)
400{
401 struct ntc_data *data = dev_get_drvdata(dev);
402 int ohm;
403
404 ohm = ntc_thermistor_get_ohm(data);
405 if (ohm < 0)
406 return ohm;
407
408 return sprintf(buf, "%d\n", get_temp_mc(data, ohm));
409}
410
411static SENSOR_DEVICE_ATTR(temp1_type, S_IRUGO, ntc_show_type, NULL, 0);
412static SENSOR_DEVICE_ATTR(temp1_input, S_IRUGO, ntc_show_temp, NULL, 0);
413static DEVICE_ATTR(name, S_IRUGO, ntc_show_name, NULL);
414
415static struct attribute *ntc_attributes[] = {
416 &dev_attr_name.attr,
417 &sensor_dev_attr_temp1_type.dev_attr.attr,
418 &sensor_dev_attr_temp1_input.dev_attr.attr,
419 NULL,
420};
421
422static const struct attribute_group ntc_attr_group = {
423 .attrs = ntc_attributes,
424};
425
426static int ntc_thermistor_probe(struct platform_device *pdev)
427{
428 const struct of_device_id *of_id =
429 of_match_device(of_match_ptr(ntc_match), &pdev->dev);
430 const struct platform_device_id *pdev_id;
431 struct ntc_thermistor_platform_data *pdata;
432 struct ntc_data *data;
433 int ret;
434
435 pdata = ntc_thermistor_parse_dt(pdev);
436 if (IS_ERR(pdata))
437 return PTR_ERR(pdata);
438 else if (pdata == NULL)
439 pdata = pdev->dev.platform_data;
440
441 if (!pdata) {
442 dev_err(&pdev->dev, "No platform init data supplied.\n");
443 return -ENODEV;
444 }
445
446
447 if (!pdata->read_uv && !pdata->read_ohm) {
448 dev_err(&pdev->dev,
449 "Both read_uv and read_ohm missing. Need either one of the two.\n");
450 return -EINVAL;
451 }
452
453 if (pdata->read_uv && pdata->read_ohm) {
454 dev_warn(&pdev->dev,
455 "Only one of read_uv and read_ohm is needed; ignoring read_uv.\n");
456 pdata->read_uv = NULL;
457 }
458
459 if (pdata->read_uv && (pdata->pullup_uv == 0 ||
460 (pdata->pullup_ohm == 0 && pdata->connect ==
461 NTC_CONNECTED_GROUND) ||
462 (pdata->pulldown_ohm == 0 && pdata->connect ==
463 NTC_CONNECTED_POSITIVE) ||
464 (pdata->connect != NTC_CONNECTED_POSITIVE &&
465 pdata->connect != NTC_CONNECTED_GROUND))) {
466 dev_err(&pdev->dev,
467 "Required data to use read_uv not supplied.\n");
468 return -EINVAL;
469 }
470
471 data = devm_kzalloc(&pdev->dev, sizeof(struct ntc_data), GFP_KERNEL);
472 if (!data)
473 return -ENOMEM;
474
475 pdev_id = of_id ? of_id->data : platform_get_device_id(pdev);
476
477 data->dev = &pdev->dev;
478 data->pdata = pdata;
479 strlcpy(data->name, pdev_id->name, sizeof(data->name));
480
481 switch (pdev_id->driver_data) {
482 case TYPE_NCPXXWB473:
483 data->comp = ncpXXwb473;
484 data->n_comp = ARRAY_SIZE(ncpXXwb473);
485 break;
486 case TYPE_NCPXXWL333:
487 data->comp = ncpXXwl333;
488 data->n_comp = ARRAY_SIZE(ncpXXwl333);
489 break;
490 default:
491 dev_err(&pdev->dev, "Unknown device type: %lu(%s)\n",
492 pdev_id->driver_data, pdev_id->name);
493 return -EINVAL;
494 }
495
496 platform_set_drvdata(pdev, data);
497
498 ret = sysfs_create_group(&data->dev->kobj, &ntc_attr_group);
499 if (ret) {
500 dev_err(data->dev, "unable to create sysfs files\n");
501 return ret;
502 }
503
504 data->hwmon_dev = hwmon_device_register(data->dev);
505 if (IS_ERR(data->hwmon_dev)) {
506 dev_err(data->dev, "unable to register as hwmon device.\n");
507 ret = PTR_ERR(data->hwmon_dev);
508 goto err_after_sysfs;
509 }
510
511 dev_info(&pdev->dev, "Thermistor type: %s successfully probed.\n",
512 pdev->name);
513
514 return 0;
515err_after_sysfs:
516 sysfs_remove_group(&data->dev->kobj, &ntc_attr_group);
517 ntc_iio_channel_release(pdata);
518 return ret;
519}
520
521static int ntc_thermistor_remove(struct platform_device *pdev)
522{
523 struct ntc_data *data = platform_get_drvdata(pdev);
524 struct ntc_thermistor_platform_data *pdata = data->pdata;
525
526 hwmon_device_unregister(data->hwmon_dev);
527 sysfs_remove_group(&data->dev->kobj, &ntc_attr_group);
528 ntc_iio_channel_release(pdata);
529 platform_set_drvdata(pdev, NULL);
530
531 return 0;
532}
533
534static struct platform_driver ntc_thermistor_driver = {
535 .driver = {
536 .name = "ntc-thermistor",
537 .owner = THIS_MODULE,
538 .of_match_table = of_match_ptr(ntc_match),
539 },
540 .probe = ntc_thermistor_probe,
541 .remove = ntc_thermistor_remove,
542 .id_table = ntc_thermistor_id,
543};
544
545module_platform_driver(ntc_thermistor_driver);
546
547MODULE_DESCRIPTION("NTC Thermistor Driver");
548MODULE_AUTHOR("MyungJoo Ham <myungjoo.ham@samsung.com>");
549MODULE_LICENSE("GPL");
550MODULE_ALIAS("platform:ntc-thermistor");
551
