summaryrefslogtreecommitdiff
path: root/drivers/misc/therm_est.c
blob: b0c09f4fd5b684a167596a9dbafb51fff17059d7 (plain)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
262
263
264
265
266
267
268
269
270
271
272
273
274
275
276
277
278
279
280
281
282
283
284
285
286
287
288
289
290
291
292
293
294
295
296
297
298
299
300
301
302
303
304
305
306
307
308
309
310
311
312
313
314
315
316
317
318
319
320
321
322
323
324
325
326
327
328
329
330
331
332
333
334
335
336
337
338
339
340
341
342
343
344
345
346
347
348
349
350
351
352
353
354
355
356
357
358
359
360
361
362
363
364
365
366
367
368
369
370
371
372
373
374
375
376
377
378
379
380
381
382
383
384
385
386
387
388
389
390
391
392
393
394
395
396
397
398
399
400
401
402
403
404
405
406
407
408
409
410
411
412
413
414
415
416
417
418
419
420
421
422
423
424
425
426
427
428
429
430
431
432
433
434
435
436
437
438
439
440
441
442
443
444
445
446
447
448
449
450
451
452
453
454
455
456
457
458
459
460
461
462
463
464
465
466
467
468
469
470
471
472
473
474
475
476
477
478
479
480
481
482
483
484
485
486
487
488
489
490
491
492
493
494
495
496
497
498
499
500
501
502
503
504
505
506
507
508
509
510
511
512
513
514
515
516
517
518
519
520
521
522
523
524
525
526
527
528
529
530
531
532
533
534
535
536
537
538
539
540
541
542
543
544
545
546
547
548
549
550
551
552
553
554
555
556
557
558
559
560
561
562
563
564
565
566
567
568
569
570
571
572
573
574
575
576
577
578
579
580
581
582
583
584
585
586
587
588
589
590
591
592
593
594
595
596
597
598
599
600
601
602
603
604
605
606
607
608
609
610
611
612
613
614
615
616
617
618
619
620
621
622
623
624
625
626
627
628
629
630
631
632
633
634
635
636
637
638
639
640
641
642
643
644
645
646
647
648
649
650
651
652
653
654
655
656
657
658
659
660
661
662
663
664
665
666
667
668
669
670
671
672
673
674
675
676
677
678
679
680
681
682
683
684
685
686
687
688
689
690
691
692
693
694
695
696
697
698
699
700
701
702
703
704
705
706
707
708
709
710
711
712
713
714
715
716
717
718
719
720
721
722
723
724
725
726
727
728
729
730
731
732
733
734
735
736
737
738
739
740
741
742
743
744
745
746
747
748
749
750
751
752
753
754
755
756
757
758
759
760
761
762
763
764
765
766
767
768
769
770
771
772
773
774
775
776
777
778
779
780
781
782
783
784
785
786
787
788
789
790
791
792
793
794
795
796
797
798
799
800
801
802
803
804
805
/*
 * drivers/misc/therm_est.c
 *
 * Copyright (c) 2010-2013, NVIDIA CORPORATION.  All rights reserved.
 *
 * This software is licensed under the terms of the GNU General Public
 * License version 2, as published by the Free Software Foundation, and
 * may be copied, distributed, and modified under those terms.
 *
 * This program is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 * GNU General Public License for more details.
 *
 */

#include <linux/platform_device.h>
#include <linux/kernel.h>
#include <linux/cpufreq.h>
#include <linux/delay.h>
#include <linux/mutex.h>
#include <linux/init.h>
#include <linux/err.h>
#include <linux/clk.h>
#include <linux/debugfs.h>
#include <linux/seq_file.h>
#include <linux/uaccess.h>
#include <linux/slab.h>
#include <linux/syscalls.h>
#include <linux/therm_est.h>
#include <linux/thermal.h>
#include <linux/module.h>
#include <linux/hwmon-sysfs.h>
#include <linux/suspend.h>

struct therm_estimator {
	struct thermal_zone_device *thz;
	int num_trips;
	struct thermal_trip_info *trips;
	struct thermal_zone_params *tzp;

	int num_timer_trips;
	struct therm_est_timer_trip_info *timer_trips;
	struct delayed_work timer_trip_work;
	struct mutex timer_trip_lock;

	struct workqueue_struct *workqueue;
	struct delayed_work therm_est_work;
	long cur_temp;
	long low_limit;
	long high_limit;
	int ntemp;
	long toffset;
	long polling_period;
	int tc1;
	int tc2;
	int ndevs;
	struct therm_est_subdevice *devs;

#ifdef CONFIG_PM
	struct notifier_block pm_nb;
#endif
};

#define TIMER_TRIP_INACTIVE		-2

#define TIMER_TRIP_STATE_NONE		0
#define TIMER_TRIP_STATE_START		BIT(0)
#define TIMER_TRIP_STATE_STOP		BIT(1)
#define TIMER_TRIP_STATE_UP		BIT(2)
#define TIMER_TRIP_STATE_DOWN		BIT(3)

static int __get_trip_temp(struct thermal_zone_device *thz, int trip,
			   long *temp);

static struct therm_est_timer_trip_info *
__find_timer_trip(struct therm_estimator *est, int trip)
{
	int i;

	/* Find matched timer trip info with trip. */
	for (i = 0; i < est->num_timer_trips; i++) {
		if (est->timer_trips[i].trip == trip)
			return &est->timer_trips[i];
	}
	return NULL;
}

static int __get_timer_trip_delay(struct therm_est_timer_trip_info *timer_info,
				 s64 now, s64 *delay)
{
	int cur = timer_info->cur;
	int next = (cur + 1 < timer_info->num_timers) ? cur + 1 : cur;

	if (cur == next) /* No more timer on this trip. */
		return -ENOENT;

	*delay = timer_info->timers[next].time_after -
		 (now - timer_info->last_tripped);
	return 0;
}

static int therm_est_subdev_match(struct thermal_zone_device *thz, void *data)
{
	return strcmp((char *)data, thz->type) == 0;
}

static int therm_est_subdev_get_temp(void *data, long *temp)
{
	struct thermal_zone_device *thz;

	thz = thermal_zone_device_find(data, therm_est_subdev_match);

	if (!thz || thz->ops->get_temp(thz, temp))
		*temp = 25000;

	return 0;
}

static void therm_est_update_limits(struct therm_estimator *est)
{
	const int MAX_HIGH_TEMP = 128000;
	long low_temp = 0, high_temp = MAX_HIGH_TEMP;
	long trip_temp, passive_low_temp = MAX_HIGH_TEMP;
	enum thermal_trip_type trip_type;
	struct thermal_trip_info *trip_state;
	int i;

	for (i = 0; i < est->num_trips; i++) {
		trip_state = &est->trips[i];
		__get_trip_temp(est->thz, i, &trip_temp);
		est->thz->ops->get_trip_type(est->thz, i, &trip_type);

		if (!trip_state->tripped) { /* not tripped? update high */
			if (trip_temp < high_temp)
				high_temp = trip_temp;
		} else { /* tripped? update low */
			if (trip_type != THERMAL_TRIP_PASSIVE) {
				/* get highest ACTIVE */
				if (trip_temp > low_temp)
					low_temp = trip_temp;
			} else {
				/* get lowest PASSIVE */
				if (trip_temp < passive_low_temp)
					passive_low_temp = trip_temp;
			}
		}
	}

	if (passive_low_temp != MAX_HIGH_TEMP)
		low_temp = max(low_temp, passive_low_temp);

	est->low_limit = low_temp;
	est->high_limit = high_temp;
}

static void therm_est_update_timer_trips(struct therm_estimator *est)
{
	struct thermal_trip_info *trip_state;
	struct therm_est_timer_trip_info *timer_info;
	s64 now, delay, min_delay;
	int i;

	mutex_lock(&est->timer_trip_lock);
	min_delay = LLONG_MAX;
	now = ktime_to_ms(ktime_get());

	for (i = 0; i < est->num_timer_trips; i++) {
		timer_info = &est->timer_trips[i];
		trip_state = &est->trips[timer_info->trip];

		pr_debug("%s: i %d, trip %d, tripped %d, cur %d\n",
			__func__, i, timer_info->trip, trip_state->tripped,
			timer_info->cur);
		if ((timer_info->cur == TIMER_TRIP_INACTIVE) ||
			(__get_timer_trip_delay(timer_info, now, &delay) < 0))
			continue;

		if (delay > 0)
			min_delay = min(min_delay, delay);
		pr_debug("%s: delay %lld, min_delay %lld\n",
			__func__, delay, min_delay);
	}
	mutex_unlock(&est->timer_trip_lock);

	cancel_delayed_work(&est->timer_trip_work);
	if (min_delay != LLONG_MAX)
		queue_delayed_work(est->workqueue, &est->timer_trip_work,
				   msecs_to_jiffies(min_delay));
}

static void therm_est_timer_trip_work_func(struct work_struct *work)
{
	struct therm_estimator *est = container_of(work, struct therm_estimator,
						   timer_trip_work.work);
	struct thermal_trip_info *trip_state;
	struct therm_est_timer_trip_info *timer_info;
	s64 now, delay;
	int timer_trip_state, i;

	mutex_lock(&est->timer_trip_lock);
	timer_trip_state = TIMER_TRIP_STATE_NONE;
	now = ktime_to_ms(ktime_get());

	for (i = 0; i < est->num_timer_trips; i++) {
		timer_info = &est->timer_trips[i];
		trip_state = &est->trips[timer_info->trip];

		pr_debug("%s: i %d, trip %d, tripped %d, cur %d\n",
			__func__, i, timer_info->trip, trip_state->tripped,
			timer_info->cur);
		if ((timer_info->cur == TIMER_TRIP_INACTIVE) ||
			(__get_timer_trip_delay(timer_info, now, &delay) < 0))
			continue;

		if (delay <= 0) { /* Timer on this trip has expired. */
			if (timer_info->cur + 1 < timer_info->num_timers) {
				timer_info->last_tripped = now;
				timer_info->cur++;
				timer_trip_state |= TIMER_TRIP_STATE_UP;
			}
		}

		/* If delay > 0, timer on this trip has not yet expired.
		 * So need to restart timer with remaining delay. */
		timer_trip_state |= TIMER_TRIP_STATE_START;
		pr_debug("%s: new_cur %d, delay %lld, timer_trip_state 0x%x\n",
			__func__, timer_info->cur, delay, timer_trip_state);
	}
	mutex_unlock(&est->timer_trip_lock);

	if (timer_trip_state & (TIMER_TRIP_STATE_START | TIMER_TRIP_STATE_UP)) {
		therm_est_update_timer_trips(est);
		therm_est_update_limits(est);
	}
}

static void therm_est_work_func(struct work_struct *work)
{
	int i, j, index, sum = 0;
	long temp;
	struct delayed_work *dwork = container_of(work,
					struct delayed_work, work);
	struct therm_estimator *est = container_of(dwork,
					struct therm_estimator,
					therm_est_work);

	for (i = 0; i < est->ndevs; i++) {
		if (therm_est_subdev_get_temp(est->devs[i].dev_data, &temp))
			continue;
		est->devs[i].hist[(est->ntemp % HIST_LEN)] = temp;
	}

	for (i = 0; i < est->ndevs; i++) {
		for (j = 0; j < HIST_LEN; j++) {
			index = (est->ntemp - j + HIST_LEN) % HIST_LEN;
			sum += est->devs[i].hist[index] *
				est->devs[i].coeffs[j];
		}
	}

	est->cur_temp = sum / 100 + est->toffset;
	est->ntemp++;

	if (est->thz && ((est->cur_temp < est->low_limit) ||
			(est->cur_temp >= est->high_limit))) {
		thermal_zone_device_update(est->thz);
		therm_est_update_timer_trips(est);
		therm_est_update_limits(est);
	}

	queue_delayed_work(est->workqueue, &est->therm_est_work,
				msecs_to_jiffies(est->polling_period));
}

static int therm_est_bind(struct thermal_zone_device *thz,
				struct thermal_cooling_device *cdev)
{
	struct therm_estimator *est = thz->devdata;
	struct thermal_trip_info *trip_state;
	int i;

	for (i = 0; i < est->num_trips; i++) {
		trip_state = &est->trips[i];
		if (trip_state->cdev_type &&
		    !strncmp(trip_state->cdev_type, cdev->type,
			     THERMAL_NAME_LENGTH))
			thermal_zone_bind_cooling_device(thz, i, cdev,
							 trip_state->upper,
							 trip_state->lower);
	}

	return 0;
}

static int therm_est_unbind(struct thermal_zone_device *thz,
				struct thermal_cooling_device *cdev)
{
	struct therm_estimator *est = thz->devdata;
	struct thermal_trip_info *trip_state;
	int i;

	for (i = 0; i < est->num_trips; i++) {
		trip_state = &est->trips[i];
		if (trip_state->cdev_type &&
		    !strncmp(trip_state->cdev_type, cdev->type,
			     THERMAL_NAME_LENGTH))
			thermal_zone_unbind_cooling_device(thz, i, cdev);
	}

	return 0;
}

static int therm_est_get_trip_type(struct thermal_zone_device *thz,
				   int trip, enum thermal_trip_type *type)
{
	struct therm_estimator *est = thz->devdata;

	*type = est->trips[trip].trip_type;
	return 0;
}

static int __get_trip_temp(struct thermal_zone_device *thz, int trip,
			   long *temp)
{
	struct therm_estimator *est = thz->devdata;
	struct thermal_trip_info *trip_state = &est->trips[trip];
	struct therm_est_timer_trip_info *timer_info;
	long zone_temp, trip_temp, hysteresis;
	int cur = TIMER_TRIP_INACTIVE;
	int ret = TIMER_TRIP_STATE_NONE;

	zone_temp = thz->temperature;
	trip_temp = trip_state->trip_temp;
	hysteresis = trip_state->hysteresis;

	timer_info = __find_timer_trip(est, trip);
	if (timer_info) {
		cur = timer_info->cur;
		/* If timer trip is available, use trip_temp and hysteresis in
		 * the timer trip to trip_temp for this trip. */
		if (timer_info->cur >= 0) {
			trip_temp = timer_info->timers[cur].trip_temp;
			hysteresis = timer_info->timers[cur].hysteresis;
		}
	}

	if (zone_temp >= trip_temp) {
		trip_temp -= hysteresis;
		if (timer_info && !trip_state->tripped)
			ret = TIMER_TRIP_STATE_START;
		trip_state->tripped = true;
	} else if (trip_state->tripped) {
		trip_temp -= hysteresis;
		if (zone_temp < trip_temp) {
			if (!timer_info) {
				trip_state->tripped = false;
			} else {
				if (cur == TIMER_TRIP_INACTIVE)
					trip_state->tripped = false;
				else
					ret = TIMER_TRIP_STATE_DOWN;
			}
		}
	}

	*temp = trip_temp;
	return ret;
}

static int therm_est_get_trip_temp(struct thermal_zone_device *thz,
				   int trip, unsigned long *temp)
{
	struct therm_estimator *est = thz->devdata;
	struct therm_est_timer_trip_info *timer_info;
	int ret;

	ret = __get_trip_temp(thz, trip, temp);
	if (ret & (TIMER_TRIP_STATE_START | TIMER_TRIP_STATE_DOWN)) {
		timer_info = __find_timer_trip(est, trip);

		mutex_lock(&est->timer_trip_lock);
		timer_info->last_tripped = ktime_to_ms(ktime_get());

		if (ret & TIMER_TRIP_STATE_START) {
			timer_info->cur = TIMER_TRIP_INACTIVE + 1;
		} else if (ret & TIMER_TRIP_STATE_DOWN) {
			if (--timer_info->cur < TIMER_TRIP_INACTIVE)
				timer_info->cur = TIMER_TRIP_INACTIVE;
		}
		mutex_unlock(&est->timer_trip_lock);

		/* Update limits, because trip temp was changed by timer trip
		 * changing. */
		therm_est_update_limits(est);
	}

	return 0;
}

static int therm_est_set_trip_temp(struct thermal_zone_device *thz,
				   int trip, unsigned long temp)
{
	struct therm_estimator *est = thz->devdata;

	est->trips[trip].trip_temp = temp;

	/* Update limits, because trip temp was changed. */
	therm_est_update_limits(est);
	return 0;
}

static int therm_est_get_temp(struct thermal_zone_device *thz,
				unsigned long *temp)
{
	struct therm_estimator *est = thz->devdata;

	*temp = est->cur_temp;
	return 0;
}

static int therm_est_get_trend(struct thermal_zone_device *thz,
			       int trip, enum thermal_trend *trend)
{
	struct therm_estimator *est = thz->devdata;
	struct thermal_trip_info *trip_state = &est->trips[trip];
	long trip_temp;
	int new_trend;
	int cur_temp;

	__get_trip_temp(thz, trip, &trip_temp);

	cur_temp = thz->temperature;
	new_trend = (est->tc1 * (cur_temp - thz->last_temperature)) +
		    (est->tc2 * (cur_temp - trip_temp));

	switch (trip_state->trip_type) {
	case THERMAL_TRIP_ACTIVE:
		/* aggressive active cooling */
		*trend = THERMAL_TREND_RAISING;
		break;
	case THERMAL_TRIP_PASSIVE:
		if (new_trend > 0)
			*trend = THERMAL_TREND_RAISING;
		else if (new_trend < 0)
			*trend = THERMAL_TREND_DROPPING;
		else
			*trend = THERMAL_TREND_STABLE;
		break;
	default:
		return -EINVAL;
	}
	return 0;
}

static struct thermal_zone_device_ops therm_est_ops = {
	.bind = therm_est_bind,
	.unbind = therm_est_unbind,
	.get_trip_type = therm_est_get_trip_type,
	.get_trip_temp = therm_est_get_trip_temp,
	.set_trip_temp = therm_est_set_trip_temp,
	.get_temp = therm_est_get_temp,
	.get_trend = therm_est_get_trend,
};

static ssize_t show_coeff(struct device *dev,
				struct device_attribute *da,
				char *buf)
{
	struct therm_estimator *est = dev_get_drvdata(dev);
	ssize_t len, total_len = 0;
	int i, j;
	for (i = 0; i < est->ndevs; i++) {
		len = snprintf(buf + total_len,
				PAGE_SIZE - total_len, "[%d]", i);
		total_len += len;
		for (j = 0; j < HIST_LEN; j++) {
			len = snprintf(buf + total_len,
					PAGE_SIZE - total_len, " %ld",
					est->devs[i].coeffs[j]);
			total_len += len;
		}
		len = snprintf(buf + total_len, PAGE_SIZE - total_len, "\n");
		total_len += len;
	}
	return strlen(buf);
}

static ssize_t set_coeff(struct device *dev,
				struct device_attribute *da,
				const char *buf, size_t count)
{
	struct therm_estimator *est = dev_get_drvdata(dev);
	int devid, scount;
	long coeff[20];

	if (HIST_LEN > 20)
		return -EINVAL;

	scount = sscanf(buf, "[%d] %ld %ld %ld %ld %ld %ld %ld %ld %ld %ld " \
			"%ld %ld %ld %ld %ld %ld %ld %ld %ld %ld",
			&devid,
			&coeff[0],
			&coeff[1],
			&coeff[2],
			&coeff[3],
			&coeff[4],
			&coeff[5],
			&coeff[6],
			&coeff[7],
			&coeff[8],
			&coeff[9],
			&coeff[10],
			&coeff[11],
			&coeff[12],
			&coeff[13],
			&coeff[14],
			&coeff[15],
			&coeff[16],
			&coeff[17],
			&coeff[18],
			&coeff[19]);

	if (scount != HIST_LEN + 1)
		return -1;

	if (devid < 0 || devid >= est->ndevs)
		return -EINVAL;

	/* This has obvious locking issues but don't worry about it */
	memcpy(est->devs[devid].coeffs, coeff, sizeof(coeff[0]) * HIST_LEN);

	return count;
}

static ssize_t show_offset(struct device *dev,
				struct device_attribute *da,
				char *buf)
{
	struct therm_estimator *est = dev_get_drvdata(dev);
	snprintf(buf, PAGE_SIZE, "%ld\n", est->toffset);
	return strlen(buf);
}

static ssize_t set_offset(struct device *dev,
				struct device_attribute *da,
				const char *buf, size_t count)
{
	struct therm_estimator *est = dev_get_drvdata(dev);
	int offset;

	if (kstrtoint(buf, 0, &offset))
		return -EINVAL;

	est->toffset = offset;

	return count;
}

static ssize_t show_temps(struct device *dev,
				struct device_attribute *da,
				char *buf)
{
	struct therm_estimator *est = dev_get_drvdata(dev);
	ssize_t total_len = 0;
	int i, j;
	int index;

	/* This has obvious locking issues but don't worry about it */
	for (i = 0; i < est->ndevs; i++) {
		total_len += snprintf(buf + total_len,
					PAGE_SIZE - total_len, "[%d]", i);
		for (j = 0; j < HIST_LEN; j++) {
			index = (est->ntemp - j + HIST_LEN) % HIST_LEN;
			total_len += snprintf(buf + total_len,
						PAGE_SIZE - total_len, " %ld",
						est->devs[i].hist[index]);
		}
		total_len += snprintf(buf + total_len,
					PAGE_SIZE - total_len, "\n");
	}
	return strlen(buf);
}

static ssize_t show_tc1(struct device *dev,
			struct device_attribute *da,
			char *buf)
{
	struct therm_estimator *est = dev_get_drvdata(dev);
	snprintf(buf, PAGE_SIZE, "%d\n", est->tc1);
	return strlen(buf);
}

static ssize_t set_tc1(struct device *dev,
			struct device_attribute *da,
			const char *buf, size_t count)
{
	struct therm_estimator *est = dev_get_drvdata(dev);
	int tc1;

	if (kstrtoint(buf, 0, &tc1))
		return -EINVAL;

	est->tc1 = tc1;

	return count;
}

static ssize_t show_tc2(struct device *dev,
			struct device_attribute *da,
			char *buf)
{
	struct therm_estimator *est = dev_get_drvdata(dev);
	snprintf(buf, PAGE_SIZE, "%d\n", est->tc2);
	return strlen(buf);
}

static ssize_t set_tc2(struct device *dev,
			struct device_attribute *da,
			const char *buf, size_t count)
{
	struct therm_estimator *est = dev_get_drvdata(dev);
	int tc2;

	if (kstrtoint(buf, 0, &tc2))
		return -EINVAL;

	est->tc2 = tc2;

	return count;
}

static struct sensor_device_attribute therm_est_nodes[] = {
	SENSOR_ATTR(coeff, S_IRUGO | S_IWUSR, show_coeff, set_coeff, 0),
	SENSOR_ATTR(offset, S_IRUGO | S_IWUSR, show_offset, set_offset, 0),
	SENSOR_ATTR(tc1, S_IRUGO | S_IWUSR, show_tc1, set_tc1, 0),
	SENSOR_ATTR(tc2, S_IRUGO | S_IWUSR, show_tc2, set_tc2, 0),
	SENSOR_ATTR(temps, S_IRUGO, show_temps, 0, 0),
};

static void therm_est_init_timer_trips(struct therm_estimator *est)
{
	int i;

	for (i = 0; i < est->num_timer_trips; i++)
		est->timer_trips[i].cur = TIMER_TRIP_INACTIVE;
}

static int therm_est_init_history(struct therm_estimator *est)
{
	int i, j;
	struct therm_est_subdevice *dev;
	long temp;

	for (i = 0; i < est->ndevs; i++) {
		dev = &est->devs[i];

		if (therm_est_subdev_get_temp(dev->dev_data, &temp))
			return -EINVAL;

		for (j = 0; j < HIST_LEN; j++)
			dev->hist[j] = temp;
	}

	return 0;
}

#ifdef CONFIG_PM
static int therm_est_pm_notify(struct notifier_block *nb,
				unsigned long event, void *data)
{
	struct therm_estimator *est = container_of(
					nb,
					struct therm_estimator,
					pm_nb);

	switch (event) {
	case PM_SUSPEND_PREPARE:
		cancel_delayed_work_sync(&est->therm_est_work);
		cancel_delayed_work_sync(&est->timer_trip_work);
		break;
	case PM_POST_SUSPEND:
		est->low_limit = 0;
		est->high_limit = 0;
		therm_est_init_history(est);
		therm_est_init_timer_trips(est);
		queue_delayed_work(est->workqueue,
				&est->therm_est_work,
				msecs_to_jiffies(est->polling_period));
		break;
	}

	return NOTIFY_OK;
}
#endif

static int therm_est_probe(struct platform_device *pdev)
{
	int i;
	struct therm_estimator *est;
	struct therm_est_data *data;

	est = kzalloc(sizeof(struct therm_estimator), GFP_KERNEL);
	if (IS_ERR_OR_NULL(est))
		return -ENOMEM;

	platform_set_drvdata(pdev, est);

	data = pdev->dev.platform_data;

	est->devs = data->devs;
	est->ndevs = data->ndevs;
	est->toffset = data->toffset;
	est->polling_period = data->polling_period;
	est->tc1 = data->tc1;
	est->tc2 = data->tc2;

	/* initialize history */
	therm_est_init_history(est);

	/* initialize timer trips */
	est->num_timer_trips = data->num_timer_trips;
	est->timer_trips = data->timer_trips;
	therm_est_init_timer_trips(est);
	mutex_init(&est->timer_trip_lock);
	INIT_DELAYED_WORK(&est->timer_trip_work,
			  therm_est_timer_trip_work_func);

	est->workqueue = alloc_workqueue(dev_name(&pdev->dev),
				    WQ_HIGHPRI | WQ_UNBOUND, 1);
	if (!est->workqueue)
		goto err;

	INIT_DELAYED_WORK(&est->therm_est_work, therm_est_work_func);

	queue_delayed_work(est->workqueue,
				&est->therm_est_work,
				msecs_to_jiffies(est->polling_period));

	est->num_trips = data->num_trips;
	est->trips = data->trips;
	est->tzp = data->tzp;

	est->thz = thermal_zone_device_register(dev_name(&pdev->dev),
						est->num_trips,
						(1 << est->num_trips) - 1,
						est,
						&therm_est_ops,
						est->tzp,
						data->passive_delay,
						0);
	if (IS_ERR_OR_NULL(est->thz))
		goto err;

	for (i = 0; i < ARRAY_SIZE(therm_est_nodes); i++)
		device_create_file(&pdev->dev, &therm_est_nodes[i].dev_attr);

#ifdef CONFIG_PM
	est->pm_nb.notifier_call = therm_est_pm_notify,
	register_pm_notifier(&est->pm_nb);
#endif

	return 0;
err:
	cancel_delayed_work_sync(&est->therm_est_work);
	if (est->workqueue)
		destroy_workqueue(est->workqueue);
	kfree(est);
	return -EINVAL;
}

static int therm_est_remove(struct platform_device *pdev)
{
	struct therm_estimator *est = platform_get_drvdata(pdev);
	int i;

	cancel_delayed_work_sync(&est->therm_est_work);
	cancel_delayed_work_sync(&est->timer_trip_work);

#ifdef CONFIG_PM
	unregister_pm_notifier(&est->pm_nb);
#endif
	for (i = 0; i < ARRAY_SIZE(therm_est_nodes); i++)
		device_remove_file(&pdev->dev, &therm_est_nodes[i].dev_attr);
	thermal_zone_device_unregister(est->thz);
	kfree(est->thz);
	destroy_workqueue(est->workqueue);
	kfree(est);
	return 0;
}

static struct platform_driver therm_est_driver = {
	.driver = {
		.owner = THIS_MODULE,
		.name  = "therm_est",
	},
	.probe  = therm_est_probe,
	.remove = therm_est_remove,
};

static int __init therm_est_driver_init(void)
{
	return platform_driver_register(&therm_est_driver);
}
module_init(therm_est_driver_init);