aboutsummaryrefslogtreecommitdiff
path: root/drivers/thermal/of-thermal.c
blob: 97d312f3b6709966fb84e153640a360d3b00ae31 (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
806
807
808
809
810
811
812
813
814
815
816
817
818
819
820
821
822
823
824
825
826
827
828
829
830
831
832
833
834
835
836
837
838
839
840
841
842
843
844
845
846
847
848
849
/*
 *  of-thermal.c - Generic Thermal Management device tree support.
 *
 *  Copyright (C) 2013 Texas Instruments
 *  Copyright (C) 2013 Eduardo Valentin <eduardo.valentin@ti.com>
 *
 *
 *  ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
 *
 *  This program is free software; you can redistribute it and/or modify
 *  it under the terms of the GNU General Public License as published by
 *  the Free Software Foundation; version 2 of the License.
 *
 *  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.
 *
 *  You should have received a copy of the GNU General Public License along
 *  with this program; if not, write to the Free Software Foundation, Inc.,
 *  59 Temple Place, Suite 330, Boston, MA 02111-1307 USA.
 *
 * ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
 */
#include <linux/thermal.h>
#include <linux/slab.h>
#include <linux/types.h>
#include <linux/of_device.h>
#include <linux/of_platform.h>
#include <linux/err.h>
#include <linux/export.h>
#include <linux/string.h>

#include "thermal_core.h"

/***   Private data structures to represent thermal device tree data ***/

/**
 * struct __thermal_trip - representation of a point in temperature domain
 * @np: pointer to struct device_node that this trip point was created from
 * @temperature: temperature value in miliCelsius
 * @hysteresis: relative hysteresis in miliCelsius
 * @type: trip point type
 */

struct __thermal_trip {
	struct device_node *np;
	unsigned long int temperature;
	unsigned long int hysteresis;
	enum thermal_trip_type type;
};

/**
 * struct __thermal_bind_param - a match between trip and cooling device
 * @cooling_device: a pointer to identify the referred cooling device
 * @trip_id: the trip point index
 * @usage: the percentage (from 0 to 100) of cooling contribution
 * @min: minimum cooling state used at this trip point
 * @max: maximum cooling state used at this trip point
 */

struct __thermal_bind_params {
	struct device_node *cooling_device;
	unsigned int trip_id;
	unsigned int usage;
	unsigned long min;
	unsigned long max;
};

/**
 * struct __thermal_zone - internal representation of a thermal zone
 * @mode: current thermal zone device mode (enabled/disabled)
 * @passive_delay: polling interval while passive cooling is activated
 * @polling_delay: zone polling interval
 * @ntrips: number of trip points
 * @trips: an array of trip points (0..ntrips - 1)
 * @num_tbps: number of thermal bind params
 * @tbps: an array of thermal bind params (0..num_tbps - 1)
 * @sensor_data: sensor private data used while reading temperature and trend
 * @get_temp: sensor callback to read temperature
 * @get_trend: sensor callback to read temperature trend
 */

struct __thermal_zone {
	enum thermal_device_mode mode;
	int passive_delay;
	int polling_delay;

	/* trip data */
	int ntrips;
	struct __thermal_trip *trips;

	/* cooling binding data */
	int num_tbps;
	struct __thermal_bind_params *tbps;

	/* sensor interface */
	void *sensor_data;
	int (*get_temp)(void *, long *);
	int (*get_trend)(void *, long *);
};

/***   DT thermal zone device callbacks   ***/

static int of_thermal_get_temp(struct thermal_zone_device *tz,
			       unsigned long *temp)
{
	struct __thermal_zone *data = tz->devdata;

	if (!data->get_temp)
		return -EINVAL;

	return data->get_temp(data->sensor_data, temp);
}

static int of_thermal_get_trend(struct thermal_zone_device *tz, int trip,
				enum thermal_trend *trend)
{
	struct __thermal_zone *data = tz->devdata;
	long dev_trend;
	int r;

	if (!data->get_trend)
		return -EINVAL;

	r = data->get_trend(data->sensor_data, &dev_trend);
	if (r)
		return r;

	/* TODO: These intervals might have some thresholds, but in core code */
	if (dev_trend > 0)
		*trend = THERMAL_TREND_RAISING;
	else if (dev_trend < 0)
		*trend = THERMAL_TREND_DROPPING;
	else
		*trend = THERMAL_TREND_STABLE;

	return 0;
}

static int of_thermal_bind(struct thermal_zone_device *thermal,
			   struct thermal_cooling_device *cdev)
{
	struct __thermal_zone *data = thermal->devdata;
	int i;

	if (!data || IS_ERR(data))
		return -ENODEV;

	/* find where to bind */
	for (i = 0; i < data->num_tbps; i++) {
		struct __thermal_bind_params *tbp = data->tbps + i;

		if (tbp->cooling_device == cdev->np) {
			int ret;

			ret = thermal_zone_bind_cooling_device(thermal,
						tbp->trip_id, cdev,
						tbp->max,
						tbp->min);
			if (ret)
				return ret;
		}
	}

	return 0;
}

static int of_thermal_unbind(struct thermal_zone_device *thermal,
			     struct thermal_cooling_device *cdev)
{
	struct __thermal_zone *data = thermal->devdata;
	int i;

	if (!data || IS_ERR(data))
		return -ENODEV;

	/* find where to unbind */
	for (i = 0; i < data->num_tbps; i++) {
		struct __thermal_bind_params *tbp = data->tbps + i;

		if (tbp->cooling_device == cdev->np) {
			int ret;

			ret = thermal_zone_unbind_cooling_device(thermal,
						tbp->trip_id, cdev);
			if (ret)
				return ret;
		}
	}

	return 0;
}

static int of_thermal_get_mode(struct thermal_zone_device *tz,
			       enum thermal_device_mode *mode)
{
	struct __thermal_zone *data = tz->devdata;

	*mode = data->mode;

	return 0;
}

static int of_thermal_set_mode(struct thermal_zone_device *tz,
			       enum thermal_device_mode mode)
{
	struct __thermal_zone *data = tz->devdata;

	mutex_lock(&tz->lock);

	if (mode == THERMAL_DEVICE_ENABLED)
		tz->polling_delay = data->polling_delay;
	else
		tz->polling_delay = 0;

	mutex_unlock(&tz->lock);

	data->mode = mode;
	thermal_zone_device_update(tz);

	return 0;
}

static int of_thermal_get_trip_type(struct thermal_zone_device *tz, int trip,
				    enum thermal_trip_type *type)
{
	struct __thermal_zone *data = tz->devdata;

	if (trip >= data->ntrips || trip < 0)
		return -EDOM;

	*type = data->trips[trip].type;

	return 0;
}

static int of_thermal_get_trip_temp(struct thermal_zone_device *tz, int trip,
				    unsigned long *temp)
{
	struct __thermal_zone *data = tz->devdata;

	if (trip >= data->ntrips || trip < 0)
		return -EDOM;

	*temp = data->trips[trip].temperature;

	return 0;
}

static int of_thermal_set_trip_temp(struct thermal_zone_device *tz, int trip,
				    unsigned long temp)
{
	struct __thermal_zone *data = tz->devdata;

	if (trip >= data->ntrips || trip < 0)
		return -EDOM;

	/* thermal framework should take care of data->mask & (1 << trip) */
	data->trips[trip].temperature = temp;

	return 0;
}

static int of_thermal_get_trip_hyst(struct thermal_zone_device *tz, int trip,
				    unsigned long *hyst)
{
	struct __thermal_zone *data = tz->devdata;

	if (trip >= data->ntrips || trip < 0)
		return -EDOM;

	*hyst = data->trips[trip].hysteresis;

	return 0;
}

static int of_thermal_set_trip_hyst(struct thermal_zone_device *tz, int trip,
				    unsigned long hyst)
{
	struct __thermal_zone *data = tz->devdata;

	if (trip >= data->ntrips || trip < 0)
		return -EDOM;

	/* thermal framework should take care of data->mask & (1 << trip) */
	data->trips[trip].hysteresis = hyst;

	return 0;
}

static int of_thermal_get_crit_temp(struct thermal_zone_device *tz,
				    unsigned long *temp)
{
	struct __thermal_zone *data = tz->devdata;
	int i;

	for (i = 0; i < data->ntrips; i++)
		if (data->trips[i].type == THERMAL_TRIP_CRITICAL) {
			*temp = data->trips[i].temperature;
			return 0;
		}

	return -EINVAL;
}

static struct thermal_zone_device_ops of_thermal_ops = {
	.get_mode = of_thermal_get_mode,
	.set_mode = of_thermal_set_mode,

	.get_trip_type = of_thermal_get_trip_type,
	.get_trip_temp = of_thermal_get_trip_temp,
	.set_trip_temp = of_thermal_set_trip_temp,
	.get_trip_hyst = of_thermal_get_trip_hyst,
	.set_trip_hyst = of_thermal_set_trip_hyst,
	.get_crit_temp = of_thermal_get_crit_temp,

	.bind = of_thermal_bind,
	.unbind = of_thermal_unbind,
};

/***   sensor API   ***/

static struct thermal_zone_device *
thermal_zone_of_add_sensor(struct device_node *zone,
			   struct device_node *sensor, void *data,
			   int (*get_temp)(void *, long *),
			   int (*get_trend)(void *, long *))
{
	struct thermal_zone_device *tzd;
	struct __thermal_zone *tz;

	tzd = thermal_zone_get_zone_by_name(zone->name);
	if (IS_ERR(tzd))
		return ERR_PTR(-EPROBE_DEFER);

	tz = tzd->devdata;

	mutex_lock(&tzd->lock);
	tz->get_temp = get_temp;
	tz->get_trend = get_trend;
	tz->sensor_data = data;

	tzd->ops->get_temp = of_thermal_get_temp;
	tzd->ops->get_trend = of_thermal_get_trend;
	mutex_unlock(&tzd->lock);

	return tzd;
}

/**
 * thermal_zone_of_sensor_register - registers a sensor to a DT thermal zone
 * @dev: a valid struct device pointer of a sensor device. Must contain
 *       a valid .of_node, for the sensor node.
 * @sensor_id: a sensor identifier, in case the sensor IP has more
 *             than one sensors
 * @data: a private pointer (owned by the caller) that will be passed
 *        back, when a temperature reading is needed.
 * @get_temp: a pointer to a function that reads the sensor temperature.
 * @get_trend: a pointer to a function that reads the sensor temperature trend.
 *
 * This function will search the list of thermal zones described in device
 * tree and look for the zone that refer to the sensor device pointed by
 * @dev->of_node as temperature providers. For the zone pointing to the
 * sensor node, the sensor will be added to the DT thermal zone device.
 *
 * The thermal zone temperature is provided by the @get_temp function
 * pointer. When called, it will have the private pointer @data back.
 *
 * The thermal zone temperature trend is provided by the @get_trend function
 * pointer. When called, it will have the private pointer @data back.
 *
 * TODO:
 * 01 - This function must enqueue the new sensor instead of using
 * it as the only source of temperature values.
 *
 * 02 - There must be a way to match the sensor with all thermal zones
 * that refer to it.
 *
 * Return: On success returns a valid struct thermal_zone_device,
 * otherwise, it returns a corresponding ERR_PTR(). Caller must
 * check the return value with help of IS_ERR() helper.
 */
struct thermal_zone_device *
thermal_zone_of_sensor_register(struct device *dev, int sensor_id,
				void *data, int (*get_temp)(void *, long *),
				int (*get_trend)(void *, long *))
{
	struct device_node *np, *child, *sensor_np;

	np = of_find_node_by_name(NULL, "thermal-zones");
	if (!np)
		return ERR_PTR(-ENODEV);

	if (!dev || !dev->of_node)
		return ERR_PTR(-EINVAL);

	sensor_np = dev->of_node;

	for_each_child_of_node(np, child) {
		struct of_phandle_args sensor_specs;
		int ret, id;

		/* For now, thermal framework supports only 1 sensor per zone */
		ret = of_parse_phandle_with_args(child, "thermal-sensors",
						 "#thermal-sensor-cells",
						 0, &sensor_specs);
		if (ret)
			continue;

		if (sensor_specs.args_count >= 1) {
			id = sensor_specs.args[0];
			WARN(sensor_specs.args_count > 1,
			     "%s: too many cells in sensor specifier %d\n",
			     sensor_specs.np->name, sensor_specs.args_count);
		} else {
			id = 0;
		}

		if (sensor_specs.np == sensor_np && id == sensor_id) {
			of_node_put(np);
			return thermal_zone_of_add_sensor(child, sensor_np,
							  data,
							  get_temp,
							  get_trend);
		}
	}
	of_node_put(np);

	return ERR_PTR(-ENODEV);
}
EXPORT_SYMBOL_GPL(thermal_zone_of_sensor_register);

/**
 * thermal_zone_of_sensor_unregister - unregisters a sensor from a DT thermal zone
 * @dev: a valid struct device pointer of a sensor device. Must contain
 *       a valid .of_node, for the sensor node.
 * @tzd: a pointer to struct thermal_zone_device where the sensor is registered.
 *
 * This function removes the sensor callbacks and private data from the
 * thermal zone device registered with thermal_zone_of_sensor_register()
 * API. It will also silent the zone by remove the .get_temp() and .get_trend()
 * thermal zone device callbacks.
 *
 * TODO: When the support to several sensors per zone is added, this
 * function must search the sensor list based on @dev parameter.
 *
 */
void thermal_zone_of_sensor_unregister(struct device *dev,
				       struct thermal_zone_device *tzd)
{
	struct __thermal_zone *tz;

	if (!dev || !tzd || !tzd->devdata)
		return;

	tz = tzd->devdata;

	/* no __thermal_zone, nothing to be done */
	if (!tz)
		return;

	mutex_lock(&tzd->lock);
	tzd->ops->get_temp = NULL;
	tzd->ops->get_trend = NULL;

	tz->get_temp = NULL;
	tz->get_trend = NULL;
	tz->sensor_data = NULL;
	mutex_unlock(&tzd->lock);
}
EXPORT_SYMBOL_GPL(thermal_zone_of_sensor_unregister);

/***   functions parsing device tree nodes   ***/

/**
 * thermal_of_populate_bind_params - parse and fill cooling map data
 * @np: DT node containing a cooling-map node
 * @__tbp: data structure to be filled with cooling map info
 * @trips: array of thermal zone trip points
 * @ntrips: number of trip points inside trips.
 *
 * This function parses a cooling-map type of node represented by
 * @np parameter and fills the read data into @__tbp data structure.
 * It needs the already parsed array of trip points of the thermal zone
 * in consideration.
 *
 * Return: 0 on success, proper error code otherwise
 */
static int thermal_of_populate_bind_params(struct device_node *np,
					   struct __thermal_bind_params *__tbp,
					   struct __thermal_trip *trips,
					   int ntrips)
{
	struct of_phandle_args cooling_spec;
	struct device_node *trip;
	int ret, i;
	u32 prop;

	/* Default weight. Usage is optional */
	__tbp->usage = 0;
	ret = of_property_read_u32(np, "contribution", &prop);
	if (ret == 0)
		__tbp->usage = prop;

	trip = of_parse_phandle(np, "trip", 0);
	if (!trip) {
		pr_err("missing trip property\n");
		return -ENODEV;
	}

	/* match using device_node */
	for (i = 0; i < ntrips; i++)
		if (trip == trips[i].np) {
			__tbp->trip_id = i;
			break;
		}

	if (i == ntrips) {
		ret = -ENODEV;
		goto end;
	}

	ret = of_parse_phandle_with_args(np, "cooling-device", "#cooling-cells",
					 0, &cooling_spec);
	if (ret < 0) {
		pr_err("missing cooling_device property\n");
		goto end;
	}
	__tbp->cooling_device = cooling_spec.np;
	if (cooling_spec.args_count >= 2) { /* at least min and max */
		__tbp->min = cooling_spec.args[0];
		__tbp->max = cooling_spec.args[1];
	} else {
		pr_err("wrong reference to cooling device, missing limits\n");
	}

end:
	of_node_put(trip);

	return ret;
}

/**
 * It maps 'enum thermal_trip_type' found in include/linux/thermal.h
 * into the device tree binding of 'trip', property type.
 */
static const char * const trip_types[] = {
	[THERMAL_TRIP_ACTIVE]	= "active",
	[THERMAL_TRIP_PASSIVE]	= "passive",
	[THERMAL_TRIP_HOT]	= "hot",
	[THERMAL_TRIP_CRITICAL]	= "critical",
};

/**
 * thermal_of_get_trip_type - Get phy mode for given device_node
 * @np:	Pointer to the given device_node
 * @type: Pointer to resulting trip type
 *
 * The function gets trip type string from property 'type',
 * and store its index in trip_types table in @type,
 *
 * Return: 0 on success, or errno in error case.
 */
static int thermal_of_get_trip_type(struct device_node *np,
				    enum thermal_trip_type *type)
{
	const char *t;
	int err, i;

	err = of_property_read_string(np, "type", &t);
	if (err < 0)
		return err;

	for (i = 0; i < ARRAY_SIZE(trip_types); i++)
		if (!strcasecmp(t, trip_types[i])) {
			*type = i;
			return 0;
		}

	return -ENODEV;
}

/**
 * thermal_of_populate_trip - parse and fill one trip point data
 * @np: DT node containing a trip point node
 * @trip: trip point data structure to be filled up
 *
 * This function parses a trip point type of node represented by
 * @np parameter and fills the read data into @trip data structure.
 *
 * Return: 0 on success, proper error code otherwise
 */
static int thermal_of_populate_trip(struct device_node *np,
				    struct __thermal_trip *trip)
{
	int prop;
	int ret;

	ret = of_property_read_u32(np, "temperature", &prop);
	if (ret < 0) {
		pr_err("missing temperature property\n");
		return ret;
	}
	trip->temperature = prop;

	ret = of_property_read_u32(np, "hysteresis", &prop);
	if (ret < 0) {
		pr_err("missing hysteresis property\n");
		return ret;
	}
	trip->hysteresis = prop;

	ret = thermal_of_get_trip_type(np, &trip->type);
	if (ret < 0) {
		pr_err("wrong trip type property\n");
		return ret;
	}

	/* Required for cooling map matching */
	trip->np = np;

	return 0;
}

/**
 * thermal_of_build_thermal_zone - parse and fill one thermal zone data
 * @np: DT node containing a thermal zone node
 *
 * This function parses a thermal zone type of node represented by
 * @np parameter and fills the read data into a __thermal_zone data structure
 * and return this pointer.
 *
 * TODO: Missing properties to parse: thermal-sensor-names and coefficients
 *
 * Return: On success returns a valid struct __thermal_zone,
 * otherwise, it returns a corresponding ERR_PTR(). Caller must
 * check the return value with help of IS_ERR() helper.
 */
static struct __thermal_zone *
thermal_of_build_thermal_zone(struct device_node *np)
{
	struct device_node *child = NULL, *gchild;
	struct __thermal_zone *tz;
	int ret, i;
	u32 prop;

	if (!np) {
		pr_err("no thermal zone np\n");
		return ERR_PTR(-EINVAL);
	}

	tz = kzalloc(sizeof(*tz), GFP_KERNEL);
	if (!tz)
		return ERR_PTR(-ENOMEM);

	ret = of_property_read_u32(np, "polling-delay-passive", &prop);
	if (ret < 0) {
		pr_err("missing polling-delay-passive property\n");
		goto free_tz;
	}
	tz->passive_delay = prop;

	ret = of_property_read_u32(np, "polling-delay", &prop);
	if (ret < 0) {
		pr_err("missing polling-delay property\n");
		goto free_tz;
	}
	tz->polling_delay = prop;

	/* trips */
	child = of_get_child_by_name(np, "trips");

	/* No trips provided */
	if (!child)
		goto finish;

	tz->ntrips = of_get_child_count(child);
	if (tz->ntrips == 0) /* must have at least one child */
		goto finish;

	tz->trips = kzalloc(tz->ntrips * sizeof(*tz->trips), GFP_KERNEL);
	if (!tz->trips) {
		ret = -ENOMEM;
		goto free_tz;
	}

	i = 0;
	for_each_child_of_node(child, gchild) {
		ret = thermal_of_populate_trip(gchild, &tz->trips[i++]);
		if (ret)
			goto free_trips;
	}

	of_node_put(child);

	/* cooling-maps */
	child = of_get_child_by_name(np, "cooling-maps");

	/* cooling-maps not provided */
	if (!child)
		goto finish;

	tz->num_tbps = of_get_child_count(child);
	if (tz->num_tbps == 0)
		goto finish;

	tz->tbps = kzalloc(tz->num_tbps * sizeof(*tz->tbps), GFP_KERNEL);
	if (!tz->tbps) {
		ret = -ENOMEM;
		goto free_trips;
	}

	i = 0;
	for_each_child_of_node(child, gchild)
		ret = thermal_of_populate_bind_params(gchild, &tz->tbps[i++],
						      tz->trips, tz->ntrips);
		if (ret)
			goto free_tbps;

finish:
	of_node_put(child);
	tz->mode = THERMAL_DEVICE_DISABLED;

	return tz;

free_tbps:
	kfree(tz->tbps);
free_trips:
	kfree(tz->trips);
free_tz:
	kfree(tz);
	of_node_put(child);

	return ERR_PTR(ret);
}

static inline void of_thermal_free_zone(struct __thermal_zone *tz)
{
	kfree(tz->tbps);
	kfree(tz->trips);
	kfree(tz);
}

/**
 * of_parse_thermal_zones - parse device tree thermal data
 *
 * Initialization function that can be called by machine initialization
 * code to parse thermal data and populate the thermal framework
 * with hardware thermal zones info. This function only parses thermal zones.
 * Cooling devices and sensor devices nodes are supposed to be parsed
 * by their respective drivers.
 *
 * Return: 0 on success, proper error code otherwise
 *
 */
int __init of_parse_thermal_zones(void)
{
	struct device_node *np, *child;
	struct __thermal_zone *tz;
	struct thermal_zone_device_ops *ops;

	np = of_find_node_by_name(NULL, "thermal-zones");
	if (!np) {
		pr_debug("unable to find thermal zones\n");
		return 0; /* Run successfully on systems without thermal DT */
	}

	for_each_child_of_node(np, child) {
		struct thermal_zone_device *zone;
		struct thermal_zone_params *tzp;

		tz = thermal_of_build_thermal_zone(child);
		if (IS_ERR(tz)) {
			pr_err("failed to build thermal zone %s: %ld\n",
			       child->name,
			       PTR_ERR(tz));
			continue;
		}

		ops = kmemdup(&of_thermal_ops, sizeof(*ops), GFP_KERNEL);
		if (!ops)
			goto exit_free;

		tzp = kzalloc(sizeof(*tzp), GFP_KERNEL);
		if (!tzp) {
			kfree(ops);
			goto exit_free;
		}

		/* No hwmon because there might be hwmon drivers registering */
		tzp->no_hwmon = true;

		zone = thermal_zone_device_register(child->name, tz->ntrips,
						    0, tz,
						    ops, tzp,
						    tz->passive_delay,
						    tz->polling_delay);
		if (IS_ERR(zone)) {
			pr_err("Failed to build %s zone %ld\n", child->name,
			       PTR_ERR(zone));
			kfree(tzp);
			kfree(ops);
			of_thermal_free_zone(tz);
			/* attempting to build remaining zones still */
		}
	}

	return 0;

exit_free:
	of_thermal_free_zone(tz);

	/* no memory available, so free what we have built */
	of_thermal_destroy_zones();

	return -ENOMEM;
}

/**
 * of_thermal_destroy_zones - remove all zones parsed and allocated resources
 *
 * Finds all zones parsed and added to the thermal framework and remove them
 * from the system, together with their resources.
 *
 */
void of_thermal_destroy_zones(void)
{
	struct device_node *np, *child;

	np = of_find_node_by_name(NULL, "thermal-zones");
	if (!np) {
		pr_err("unable to find thermal zones\n");
		return;
	}

	for_each_child_of_node(np, child) {
		struct thermal_zone_device *zone;

		zone = thermal_zone_get_zone_by_name(child->name);
		if (IS_ERR(zone))
			continue;

		thermal_zone_device_unregister(zone);
		kfree(zone->tzp);
		kfree(zone->ops);
		of_thermal_free_zone(zone->devdata);
	}
}