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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
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
56
57
58
59
60
61
62static const struct ntc_compensation ncpXXwb473[] = {
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};
98static const struct ntc_compensation ncpXXwl333[] = {
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
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
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
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
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
239static int get_ohm_of_thermistor(struct ntc_data *data, unsigned int uv)
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)
250 return INT_MAX;
251 return 0;
252 }
253 if (mv >= pmv)
254 return (pdata->connect == NTC_CONNECTED_POSITIVE) ?
255 0 : INT_MAX;
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
267 if (n > INT_MAX)
268 n = INT_MAX;
269 return n;
270}
271
272static void lookup_comp(struct ntc_data *data, unsigned int ohm,
273 int *i_low, int *i_high)
274{
275 int start, end, mid;
276
277
278
279
280
281
282
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 }
294
295
296 start = 0;
297 end = data->n_comp;
298 while (start < end) {
299 mid = start + (end - start) / 2;
300
301
302
303
304
305
306
307
308
309 if (ohm >= data->comp[mid].ohm) {
310 end = mid;
311 } else {
312 start = mid + 1;
313
314
315
316
317
318
319 if (ohm >= data->comp[start].ohm)
320 end = start;
321 }
322
323
324
325
326 }
327
328
329
330
331 *i_low = end;
332 if (ohm == data->comp[end].ohm)
333 *i_high = end;
334 else
335 *i_high = end - 1;
336}
337
338static int get_temp_mc(struct ntc_data *data, unsigned int ohm)
339{
340 int low, high;
341 int temp;
342
343 lookup_comp(data, ohm, &low, &high);
344 if (low == high) {
345
346 temp = data->comp[low].temp_c * 1000;
347 } else {
348 temp = data->comp[low].temp_c * 1000 +
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 }
353 return temp;
354}
355
356static int ntc_thermistor_get_ohm(struct ntc_data *data)
357{
358 int read_uv;
359
360 if (data->pdata->read_ohm)
361 return data->pdata->read_ohm();
362
363 if (data->pdata->read_uv) {
364 read_uv = data->pdata->read_uv(data->pdata);
365 if (read_uv < 0)
366 return read_uv;
367 return get_ohm_of_thermistor(data, read_uv);
368 }
369 return -EINVAL;
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);
390 int ohm;
391
392 ohm = ntc_thermistor_get_ohm(data);
393 if (ohm < 0)
394 return ohm;
395
396 return sprintf(buf, "%d\n", get_temp_mc(data, ohm));
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
414static int ntc_thermistor_probe(struct platform_device *pdev)
415{
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;
420 struct ntc_data *data;
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;
428
429 if (!pdata) {
430 dev_err(&pdev->dev, "No platform init data supplied.\n");
431 return -ENODEV;
432 }
433
434
435 if (!pdata->read_uv && !pdata->read_ohm) {
436 dev_err(&pdev->dev,
437 "Both read_uv and read_ohm missing. Need either one of the two.\n");
438 return -EINVAL;
439 }
440
441 if (pdata->read_uv && pdata->read_ohm) {
442 dev_warn(&pdev->dev,
443 "Only one of read_uv and read_ohm is needed; ignoring read_uv.\n");
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))) {
454 dev_err(&pdev->dev,
455 "Required data to use read_uv not supplied.\n");
456 return -EINVAL;
457 }
458
459 data = devm_kzalloc(&pdev->dev, sizeof(struct ntc_data), GFP_KERNEL);
460 if (!data)
461 return -ENOMEM;
462
463 pdev_id = of_id ? of_id->data : platform_get_device_id(pdev);
464
465 data->dev = &pdev->dev;
466 data->pdata = pdata;
467 strlcpy(data->name, pdev_id->name, sizeof(data->name));
468
469 switch (pdev_id->driver_data) {
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",
480 pdev_id->driver_data, pdev_id->name);
481 return -EINVAL;
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");
489 return ret;
490 }
491
492 data->hwmon_dev = hwmon_device_register(data->dev);
493 if (IS_ERR(data->hwmon_dev)) {
494 dev_err(data->dev, "unable to register as hwmon device.\n");
495 ret = PTR_ERR(data->hwmon_dev);
496 goto err_after_sysfs;
497 }
498
499 dev_info(&pdev->dev, "Thermistor type: %s successfully probed.\n",
500 pdev->name);
501
502 return 0;
503err_after_sysfs:
504 sysfs_remove_group(&data->dev->kobj, &ntc_attr_group);
505 ntc_iio_channel_release(pdata);
506 return ret;
507}
508
509static int ntc_thermistor_remove(struct platform_device *pdev)
510{
511 struct ntc_data *data = platform_get_drvdata(pdev);
512 struct ntc_thermistor_platform_data *pdata = data->pdata;
513
514 hwmon_device_unregister(data->hwmon_dev);
515 sysfs_remove_group(&data->dev->kobj, &ntc_attr_group);
516 ntc_iio_channel_release(pdata);
517 platform_set_drvdata(pdev, NULL);
518
519 return 0;
520}
521
522static struct platform_driver ntc_thermistor_driver = {
523 .driver = {
524 .name = "ntc-thermistor",
525 .owner = THIS_MODULE,
526 .of_match_table = of_match_ptr(ntc_match),
527 },
528 .probe = ntc_thermistor_probe,
529 .remove = ntc_thermistor_remove,
530 .id_table = ntc_thermistor_id,
531};
532
533module_platform_driver(ntc_thermistor_driver);
534
535MODULE_DESCRIPTION("NTC Thermistor Driver");
536MODULE_AUTHOR("MyungJoo Ham <myungjoo.ham@samsung.com>");
537MODULE_LICENSE("GPL");
538MODULE_ALIAS("platform:ntc-thermistor");
539
