summaryrefslogtreecommitdiffstats
path: root/drivers/opp/of.c
blob: 1f0923cc1cd934d7d50b87ecee3a97275ae99ef9 (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
850
851
852
853
854
855
856
857
858
859
860
861
862
863
864
865
866
867
868
869
870
871
872
873
874
875
876
877
878
879
880
881
882
883
884
885
886
887
888
889
890
891
892
893
894
895
896
897
898
899
900
901
902
903
904
905
906
907
908
909
910
911
912
913
914
915
916
917
918
919
920
921
922
923
924
925
926
927
928
929
930
931
932
933
934
935
936
937
938
939
940
941
942
943
944
945
946
947
948
949
950
951
952
953
954
955
956
957
958
959
960
961
962
963
964
965
966
967
968
969
970
971
972
973
974
975
976
977
978
979
980
981
982
983
984
985
986
987
988
989
990
991
992
993
994
995
996
997
998
999
1000
1001
1002
1003
1004
1005
1006
1007
1008
1009
1010
1011
1012
1013
1014
1015
1016
1017
1018
1019
1020
1021
1022
1023
1024
1025
1026
1027
1028
1029
1030
1031
1032
1033
1034
1035
1036
1037
1038
1039
1040
1041
1042
1043
1044
1045
1046
1047
1048
1049
1050
1051
1052
1053
1054
1055
1056
1057
1058
1059
1060
1061
1062
1063
1064
1065
1066
1067
1068
1069
1070
1071
1072
1073
1074
1075
1076
1077
1078
1079
1080
1081
1082
1083
1084
1085
1086
1087
1088
1089
1090
1091
1092
1093
1094
1095
1096
1097
1098
1099
1100
1101
1102
1103
1104
1105
1106
1107
1108
1109
1110
1111
1112
1113
1114
1115
1116
1117
1118
1119
1120
1121
1122
1123
1124
1125
1126
1127
1128
1129
1130
1131
1132
1133
1134
1135
1136
1137
1138
1139
1140
1141
1142
1143
1144
1145
1146
1147
1148
1149
1150
1151
1152
1153
1154
1155
1156
1157
1158
1159
1160
1161
1162
1163
1164
1165
1166
1167
1168
1169
1170
1171
1172
1173
1174
1175
1176
1177
1178
1179
1180
1181
1182
1183
1184
1185
1186
1187
1188
1189
1190
1191
1192
1193
1194
1195
1196
1197
1198
1199
1200
1201
1202
1203
1204
1205
1206
1207
1208
1209
1210
1211
1212
1213
1214
1215
1216
1217
1218
1219
1220
1221
1222
1223
1224
1225
1226
1227
1228
1229
1230
1231
1232
1233
1234
1235
1236
1237
1238
1239
1240
1241
1242
1243
1244
1245
1246
1247
1248
1249
1250
1251
1252
1253
1254
1255
1256
1257
1258
1259
1260
1261
1262
1263
1264
1265
1266
1267
1268
1269
1270
1271
1272
1273
1274
1275
1276
1277
1278
1279
1280
1281
1282
1283
1284
1285
1286
1287
1288
1289
1290
1291
1292
1293
1294
1295
1296
1297
1298
1299
1300
1301
1302
1303
1304
1305
1306
1307
1308
1309
1310
1311
1312
1313
1314
1315
1316
1317
1318
1319
1320
1321
1322
1323
1324
1325
1326
1327
1328
1329
1330
1331
1332
1333
1334
1335
1336
1337
1338
1339
1340
1341
1342
1343
1344
1345
1346
1347
1348
1349
1350
1351
1352
1353
1354
1355
1356
1357
1358
1359
1360
1361
1362
1363
1364
1365
1366
1367
1368
1369
1370
1371
1372
1373
1374
1375
1376
1377
1378
1379
1380
1381
1382
1383
1384
1385
1386
1387
1388
1389
1390
1391
1392
1393
1394
1395
1396
1397
1398
1399
1400
1401
1402
1403
1404
1405
1406
1407
1408
1409
1410
1411
1412
1413
1414
1415
1416
1417
1418
1419
1420
1421
1422
1423
1424
1425
1426
1427
1428
1429
1430
1431
1432
1433
1434
1435
1436
1437
1438
1439
1440
1441
1442
1443
1444
1445
1446
1447
1448
1449
1450
1451
1452
1453
1454
1455
1456
1457
1458
1459
1460
1461
1462
1463
1464
1465
1466
1467
1468
1469
1470
1471
1472
1473
1474
1475
1476
1477
1478
1479
1480
1481
1482
1483
1484
1485
1486
1487
1488
1489
1490
1491
1492
1493
1494
1495
1496
1497
1498
1499
1500
1501
1502
1503
1504
1505
1506
1507
1508
1509
1510
1511
1512
1513
1514
1515
1516
1517
1518
1519
1520
1521
1522
1523
1524
1525
1526
1527
1528
1529
1530
1531
1532
1533
1534
1535
1536
1537
1538
1539
1540
1541
1542
1543
1544
1545
1546
1547
1548
1549
1550
1551
1552
1553
1554
1555
1556
1557
1558
1559
1560
1561
1562
1563
1564
1565
1566
1567
1568
1569
1570
1571
1572
1573
1574
1575
1576
1577
1578
1579
1580
1581
1582
1583
1584
1585
1586
1587
1588
1589
1590
1591
1592
1593
1594
1595
1596
1597
1598
// SPDX-License-Identifier: GPL-2.0-only
/*
 * Generic OPP OF helpers
 *
 * Copyright (C) 2009-2010 Texas Instruments Incorporated.
 *	Nishanth Menon
 *	Romit Dasgupta
 *	Kevin Hilman
 */

#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt

#include <linux/cpu.h>
#include <linux/errno.h>
#include <linux/device.h>
#include <linux/of.h>
#include <linux/pm_domain.h>
#include <linux/slab.h>
#include <linux/export.h>
#include <linux/energy_model.h>

#include "opp.h"

/* OPP tables with uninitialized required OPPs, protected by opp_table_lock */
static LIST_HEAD(lazy_opp_tables);

/*
 * Returns opp descriptor node for a device node, caller must
 * do of_node_put().
 */
static struct device_node *_opp_of_get_opp_desc_node(struct device_node *np,
						     int index)
{
	/* "operating-points-v2" can be an array for power domain providers */
	return of_parse_phandle(np, "operating-points-v2", index);
}

/* Returns opp descriptor node for a device, caller must do of_node_put() */
struct device_node *dev_pm_opp_of_get_opp_desc_node(struct device *dev)
{
	return _opp_of_get_opp_desc_node(dev->of_node, 0);
}
EXPORT_SYMBOL_GPL(dev_pm_opp_of_get_opp_desc_node);

struct opp_table *_managed_opp(struct device *dev, int index)
{
	struct opp_table *opp_table, *managed_table = NULL;
	struct device_node *np;

	np = _opp_of_get_opp_desc_node(dev->of_node, index);
	if (!np)
		return NULL;

	list_for_each_entry(opp_table, &opp_tables, node) {
		if (opp_table->np == np) {
			/*
			 * Multiple devices can point to the same OPP table and
			 * so will have same node-pointer, np.
			 *
			 * But the OPPs will be considered as shared only if the
			 * OPP table contains a "opp-shared" property.
			 */
			if (opp_table->shared_opp == OPP_TABLE_ACCESS_SHARED) {
				_get_opp_table_kref(opp_table);
				managed_table = opp_table;
			}

			break;
		}
	}

	of_node_put(np);

	return managed_table;
}

/* The caller must call dev_pm_opp_put() after the OPP is used */
static struct dev_pm_opp *_find_opp_of_np(struct opp_table *opp_table,
					  struct device_node *opp_np)
{
	struct dev_pm_opp *opp;

	mutex_lock(&opp_table->lock);

	list_for_each_entry(opp, &opp_table->opp_list, node) {
		if (opp->np == opp_np) {
			dev_pm_opp_get(opp);
			mutex_unlock(&opp_table->lock);
			return opp;
		}
	}

	mutex_unlock(&opp_table->lock);

	return NULL;
}

static struct device_node *of_parse_required_opp(struct device_node *np,
						 int index)
{
	return of_parse_phandle(np, "required-opps", index);
}

/* The caller must call dev_pm_opp_put_opp_table() after the table is used */
static struct opp_table *_find_table_of_opp_np(struct device_node *opp_np)
{
	struct opp_table *opp_table;
	struct device_node *opp_table_np;

	opp_table_np = of_get_parent(opp_np);
	if (!opp_table_np)
		goto err;

	/* It is safe to put the node now as all we need now is its address */
	of_node_put(opp_table_np);

	mutex_lock(&opp_table_lock);
	list_for_each_entry(opp_table, &opp_tables, node) {
		if (opp_table_np == opp_table->np) {
			_get_opp_table_kref(opp_table);
			mutex_unlock(&opp_table_lock);
			return opp_table;
		}
	}
	mutex_unlock(&opp_table_lock);

err:
	return ERR_PTR(-ENODEV);
}

/* Free resources previously acquired by _opp_table_alloc_required_tables() */
static void _opp_table_free_required_tables(struct opp_table *opp_table)
{
	struct opp_table **required_opp_tables = opp_table->required_opp_tables;
	int i;

	if (!required_opp_tables)
		return;

	for (i = 0; i < opp_table->required_opp_count; i++) {
		if (IS_ERR_OR_NULL(required_opp_tables[i]))
			continue;

		dev_pm_opp_put_opp_table(required_opp_tables[i]);
	}

	kfree(required_opp_tables);

	opp_table->required_opp_count = 0;
	opp_table->required_opp_tables = NULL;

	mutex_lock(&opp_table_lock);
	list_del(&opp_table->lazy);
	mutex_unlock(&opp_table_lock);
}

/*
 * Populate all devices and opp tables which are part of "required-opps" list.
 * Checking only the first OPP node should be enough.
 */
static void _opp_table_alloc_required_tables(struct opp_table *opp_table,
					     struct device *dev,
					     struct device_node *opp_np)
{
	struct opp_table **required_opp_tables;
	struct device_node *required_np, *np;
	bool lazy = false;
	int count, i;

	/* Traversing the first OPP node is all we need */
	np = of_get_next_available_child(opp_np, NULL);
	if (!np) {
		dev_warn(dev, "Empty OPP table\n");

		return;
	}

	count = of_count_phandle_with_args(np, "required-opps", NULL);
	if (count <= 0)
		goto put_np;

	required_opp_tables = kcalloc(count, sizeof(*required_opp_tables),
				      GFP_KERNEL);
	if (!required_opp_tables)
		goto put_np;

	opp_table->required_opp_tables = required_opp_tables;
	opp_table->required_opp_count = count;

	for (i = 0; i < count; i++) {
		required_np = of_parse_required_opp(np, i);
		if (!required_np)
			goto free_required_tables;

		required_opp_tables[i] = _find_table_of_opp_np(required_np);
		of_node_put(required_np);

		if (IS_ERR(required_opp_tables[i]))
			lazy = true;
	}

	/* Let's do the linking later on */
	if (lazy) {
		/*
		 * The OPP table is not held while allocating the table, take it
		 * now to avoid corruption to the lazy_opp_tables list.
		 */
		mutex_lock(&opp_table_lock);
		list_add(&opp_table->lazy, &lazy_opp_tables);
		mutex_unlock(&opp_table_lock);
	}
	else
		_update_set_required_opps(opp_table);

	goto put_np;

free_required_tables:
	_opp_table_free_required_tables(opp_table);
put_np:
	of_node_put(np);
}

void _of_init_opp_table(struct opp_table *opp_table, struct device *dev,
			int index)
{
	struct device_node *np, *opp_np;
	u32 val;

	/*
	 * Only required for backward compatibility with v1 bindings, but isn't
	 * harmful for other cases. And so we do it unconditionally.
	 */
	np = of_node_get(dev->of_node);
	if (!np)
		return;

	if (!of_property_read_u32(np, "clock-latency", &val))
		opp_table->clock_latency_ns_max = val;
	of_property_read_u32(np, "voltage-tolerance",
			     &opp_table->voltage_tolerance_v1);

	if (of_property_present(np, "#power-domain-cells"))
		opp_table->is_genpd = true;

	/* Get OPP table node */
	opp_np = _opp_of_get_opp_desc_node(np, index);
	of_node_put(np);

	if (!opp_np)
		return;

	if (of_property_read_bool(opp_np, "opp-shared"))
		opp_table->shared_opp = OPP_TABLE_ACCESS_SHARED;
	else
		opp_table->shared_opp = OPP_TABLE_ACCESS_EXCLUSIVE;

	opp_table->np = opp_np;

	_opp_table_alloc_required_tables(opp_table, dev, opp_np);
}

void _of_clear_opp_table(struct opp_table *opp_table)
{
	_opp_table_free_required_tables(opp_table);
	of_node_put(opp_table->np);
}

/*
 * Release all resources previously acquired with a call to
 * _of_opp_alloc_required_opps().
 */
static void _of_opp_free_required_opps(struct opp_table *opp_table,
				       struct dev_pm_opp *opp)
{
	struct dev_pm_opp **required_opps = opp->required_opps;
	int i;

	if (!required_opps)
		return;

	for (i = 0; i < opp_table->required_opp_count; i++) {
		if (!required_opps[i])
			continue;

		/* Put the reference back */
		dev_pm_opp_put(required_opps[i]);
	}

	opp->required_opps = NULL;
	kfree(required_opps);
}

void _of_clear_opp(struct opp_table *opp_table, struct dev_pm_opp *opp)
{
	_of_opp_free_required_opps(opp_table, opp);
	of_node_put(opp->np);
}

/* Populate all required OPPs which are part of "required-opps" list */
static int _of_opp_alloc_required_opps(struct opp_table *opp_table,
				       struct dev_pm_opp *opp)
{
	struct dev_pm_opp **required_opps;
	struct opp_table *required_table;
	struct device_node *np;
	int i, ret, count = opp_table->required_opp_count;

	if (!count)
		return 0;

	required_opps = kcalloc(count, sizeof(*required_opps), GFP_KERNEL);
	if (!required_opps)
		return -ENOMEM;

	opp->required_opps = required_opps;

	for (i = 0; i < count; i++) {
		required_table = opp_table->required_opp_tables[i];

		/* Required table not added yet, we will link later */
		if (IS_ERR_OR_NULL(required_table))
			continue;

		np = of_parse_required_opp(opp->np, i);
		if (unlikely(!np)) {
			ret = -ENODEV;
			goto free_required_opps;
		}

		required_opps[i] = _find_opp_of_np(required_table, np);
		of_node_put(np);

		if (!required_opps[i]) {
			pr_err("%s: Unable to find required OPP node: %pOF (%d)\n",
			       __func__, opp->np, i);
			ret = -ENODEV;
			goto free_required_opps;
		}
	}

	return 0;

free_required_opps:
	_of_opp_free_required_opps(opp_table, opp);

	return ret;
}

/* Link required OPPs for an individual OPP */
static int lazy_link_required_opps(struct opp_table *opp_table,
				   struct opp_table *new_table, int index)
{
	struct device_node *required_np;
	struct dev_pm_opp *opp;

	list_for_each_entry(opp, &opp_table->opp_list, node) {
		required_np = of_parse_required_opp(opp->np, index);
		if (unlikely(!required_np))
			return -ENODEV;

		opp->required_opps[index] = _find_opp_of_np(new_table, required_np);
		of_node_put(required_np);

		if (!opp->required_opps[index]) {
			pr_err("%s: Unable to find required OPP node: %pOF (%d)\n",
			       __func__, opp->np, index);
			return -ENODEV;
		}
	}

	return 0;
}

/* Link required OPPs for all OPPs of the newly added OPP table */
static void lazy_link_required_opp_table(struct opp_table *new_table)
{
	struct opp_table *opp_table, *temp, **required_opp_tables;
	struct device_node *required_np, *opp_np, *required_table_np;
	struct dev_pm_opp *opp;
	int i, ret;

	mutex_lock(&opp_table_lock);

	list_for_each_entry_safe(opp_table, temp, &lazy_opp_tables, lazy) {
		bool lazy = false;

		/* opp_np can't be invalid here */
		opp_np = of_get_next_available_child(opp_table->np, NULL);

		for (i = 0; i < opp_table->required_opp_count; i++) {
			required_opp_tables = opp_table->required_opp_tables;

			/* Required opp-table is already parsed */
			if (!IS_ERR(required_opp_tables[i]))
				continue;

			/* required_np can't be invalid here */
			required_np = of_parse_required_opp(opp_np, i);
			required_table_np = of_get_parent(required_np);

			of_node_put(required_table_np);
			of_node_put(required_np);

			/*
			 * Newly added table isn't the required opp-table for
			 * opp_table.
			 */
			if (required_table_np != new_table->np) {
				lazy = true;
				continue;
			}

			required_opp_tables[i] = new_table;
			_get_opp_table_kref(new_table);

			/* Link OPPs now */
			ret = lazy_link_required_opps(opp_table, new_table, i);
			if (ret) {
				/* The OPPs will be marked unusable */
				lazy = false;
				break;
			}
		}

		of_node_put(opp_np);

		/* All required opp-tables found, remove from lazy list */
		if (!lazy) {
			_update_set_required_opps(opp_table);
			list_del_init(&opp_table->lazy);

			list_for_each_entry(opp, &opp_table->opp_list, node)
				_required_opps_available(opp, opp_table->required_opp_count);
		}
	}

	mutex_unlock(&opp_table_lock);
}

static int _bandwidth_supported(struct device *dev, struct opp_table *opp_table)
{
	struct device_node *np, *opp_np;
	struct property *prop;

	if (!opp_table) {
		np = of_node_get(dev->of_node);
		if (!np)
			return -ENODEV;

		opp_np = _opp_of_get_opp_desc_node(np, 0);
		of_node_put(np);
	} else {
		opp_np = of_node_get(opp_table->np);
	}

	/* Lets not fail in case we are parsing opp-v1 bindings */
	if (!opp_np)
		return 0;

	/* Checking only first OPP is sufficient */
	np = of_get_next_available_child(opp_np, NULL);
	of_node_put(opp_np);
	if (!np) {
		dev_err(dev, "OPP table empty\n");
		return -EINVAL;
	}

	prop = of_find_property(np, "opp-peak-kBps", NULL);
	of_node_put(np);

	if (!prop || !prop->length)
		return 0;

	return 1;
}

int dev_pm_opp_of_find_icc_paths(struct device *dev,
				 struct opp_table *opp_table)
{
	struct device_node *np;
	int ret, i, count, num_paths;
	struct icc_path **paths;

	ret = _bandwidth_supported(dev, opp_table);
	if (ret == -EINVAL)
		return 0; /* Empty OPP table is a valid corner-case, let's not fail */
	else if (ret <= 0)
		return ret;

	ret = 0;

	np = of_node_get(dev->of_node);
	if (!np)
		return 0;

	count = of_count_phandle_with_args(np, "interconnects",
					   "#interconnect-cells");
	of_node_put(np);
	if (count < 0)
		return 0;

	/* two phandles when #interconnect-cells = <1> */
	if (count % 2) {
		dev_err(dev, "%s: Invalid interconnects values\n", __func__);
		return -EINVAL;
	}

	num_paths = count / 2;
	paths = kcalloc(num_paths, sizeof(*paths), GFP_KERNEL);
	if (!paths)
		return -ENOMEM;

	for (i = 0; i < num_paths; i++) {
		paths[i] = of_icc_get_by_index(dev, i);
		if (IS_ERR(paths[i])) {
			ret = dev_err_probe(dev, ret, "%s: Unable to get path%d\n", __func__, i);
			goto err;
		}
	}

	if (opp_table) {
		opp_table->paths = paths;
		opp_table->path_count = num_paths;
		return 0;
	}

err:
	while (i--)
		icc_put(paths[i]);

	kfree(paths);

	return ret;
}
EXPORT_SYMBOL_GPL(dev_pm_opp_of_find_icc_paths);

static bool _opp_is_supported(struct device *dev, struct opp_table *opp_table,
			      struct device_node *np)
{
	unsigned int levels = opp_table->supported_hw_count;
	int count, versions, ret, i, j;
	u32 val;

	if (!opp_table->supported_hw) {
		/*
		 * In the case that no supported_hw has been set by the
		 * platform but there is an opp-supported-hw value set for
		 * an OPP then the OPP should not be enabled as there is
		 * no way to see if the hardware supports it.
		 */
		if (of_property_present(np, "opp-supported-hw"))
			return false;
		else
			return true;
	}

	count = of_property_count_u32_elems(np, "opp-supported-hw");
	if (count <= 0 || count % levels) {
		dev_err(dev, "%s: Invalid opp-supported-hw property (%d)\n",
			__func__, count);
		return false;
	}

	versions = count / levels;

	/* All levels in at least one of the versions should match */
	for (i = 0; i < versions; i++) {
		bool supported = true;

		for (j = 0; j < levels; j++) {
			ret = of_property_read_u32_index(np, "opp-supported-hw",
							 i * levels + j, &val);
			if (ret) {
				dev_warn(dev, "%s: failed to read opp-supported-hw property at index %d: %d\n",
					 __func__, i * levels + j, ret);
				return false;
			}

			/* Check if the level is supported */
			if (!(val & opp_table->supported_hw[j])) {
				supported = false;
				break;
			}
		}

		if (supported)
			return true;
	}

	return false;
}

static u32 *_parse_named_prop(struct dev_pm_opp *opp, struct device *dev,
			      struct opp_table *opp_table,
			      const char *prop_type, bool *triplet)
{
	struct property *prop = NULL;
	char name[NAME_MAX];
	int count, ret;
	u32 *out;

	/* Search for "opp-<prop_type>-<name>" */
	if (opp_table->prop_name) {
		snprintf(name, sizeof(name), "opp-%s-%s", prop_type,
			 opp_table->prop_name);
		prop = of_find_property(opp->np, name, NULL);
	}

	if (!prop) {
		/* Search for "opp-<prop_type>" */
		snprintf(name, sizeof(name), "opp-%s", prop_type);
		prop = of_find_property(opp->np, name, NULL);
		if (!prop)
			return NULL;
	}

	count = of_property_count_u32_elems(opp->np, name);
	if (count < 0) {
		dev_err(dev, "%s: Invalid %s property (%d)\n", __func__, name,
			count);
		return ERR_PTR(count);
	}

	/*
	 * Initialize regulator_count, if regulator information isn't provided
	 * by the platform. Now that one of the properties is available, fix the
	 * regulator_count to 1.
	 */
	if (unlikely(opp_table->regulator_count == -1))
		opp_table->regulator_count = 1;

	if (count != opp_table->regulator_count &&
	    (!triplet || count != opp_table->regulator_count * 3)) {
		dev_err(dev, "%s: Invalid number of elements in %s property (%u) with supplies (%d)\n",
			__func__, prop_type, count, opp_table->regulator_count);
		return ERR_PTR(-EINVAL);
	}

	out = kmalloc_array(count, sizeof(*out), GFP_KERNEL);
	if (!out)
		return ERR_PTR(-EINVAL);

	ret = of_property_read_u32_array(opp->np, name, out, count);
	if (ret) {
		dev_err(dev, "%s: error parsing %s: %d\n", __func__, name, ret);
		kfree(out);
		return ERR_PTR(-EINVAL);
	}

	if (triplet)
		*triplet = count != opp_table->regulator_count;

	return out;
}

static u32 *opp_parse_microvolt(struct dev_pm_opp *opp, struct device *dev,
				struct opp_table *opp_table, bool *triplet)
{
	u32 *microvolt;

	microvolt = _parse_named_prop(opp, dev, opp_table, "microvolt", triplet);
	if (IS_ERR(microvolt))
		return microvolt;

	if (!microvolt) {
		/*
		 * Missing property isn't a problem, but an invalid
		 * entry is. This property isn't optional if regulator
		 * information is provided. Check only for the first OPP, as
		 * regulator_count may get initialized after that to a valid
		 * value.
		 */
		if (list_empty(&opp_table->opp_list) &&
		    opp_table->regulator_count > 0) {
			dev_err(dev, "%s: opp-microvolt missing although OPP managing regulators\n",
				__func__);
			return ERR_PTR(-EINVAL);
		}
	}

	return microvolt;
}

static int opp_parse_supplies(struct dev_pm_opp *opp, struct device *dev,
			      struct opp_table *opp_table)
{
	u32 *microvolt, *microamp, *microwatt;
	int ret = 0, i, j;
	bool triplet;

	microvolt = opp_parse_microvolt(opp, dev, opp_table, &triplet);
	if (IS_ERR(microvolt))
		return PTR_ERR(microvolt);

	microamp = _parse_named_prop(opp, dev, opp_table, "microamp", NULL);
	if (IS_ERR(microamp)) {
		ret = PTR_ERR(microamp);
		goto free_microvolt;
	}

	microwatt = _parse_named_prop(opp, dev, opp_table, "microwatt", NULL);
	if (IS_ERR(microwatt)) {
		ret = PTR_ERR(microwatt);
		goto free_microamp;
	}

	/*
	 * Initialize regulator_count if it is uninitialized and no properties
	 * are found.
	 */
	if (unlikely(opp_table->regulator_count == -1)) {
		opp_table->regulator_count = 0;
		return 0;
	}

	for (i = 0, j = 0; i < opp_table->regulator_count; i++) {
		if (microvolt) {
			opp->supplies[i].u_volt = microvolt[j++];

			if (triplet) {
				opp->supplies[i].u_volt_min = microvolt[j++];
				opp->supplies[i].u_volt_max = microvolt[j++];
			} else {
				opp->supplies[i].u_volt_min = opp->supplies[i].u_volt;
				opp->supplies[i].u_volt_max = opp->supplies[i].u_volt;
			}
		}

		if (microamp)
			opp->supplies[i].u_amp = microamp[i];

		if (microwatt)
			opp->supplies[i].u_watt = microwatt[i];
	}

	kfree(microwatt);
free_microamp:
	kfree(microamp);
free_microvolt:
	kfree(microvolt);

	return ret;
}

/**
 * dev_pm_opp_of_remove_table() - Free OPP table entries created from static DT
 *				  entries
 * @dev:	device pointer used to lookup OPP table.
 *
 * Free OPPs created using static entries present in DT.
 */
void dev_pm_opp_of_remove_table(struct device *dev)
{
	dev_pm_opp_remove_table(dev);
}
EXPORT_SYMBOL_GPL(dev_pm_opp_of_remove_table);

static int _read_rate(struct dev_pm_opp *new_opp, struct opp_table *opp_table,
		      struct device_node *np)
{
	struct property *prop;
	int i, count, ret;
	u64 *rates;

	prop = of_find_property(np, "opp-hz", NULL);
	if (!prop)
		return -ENODEV;

	count = prop->length / sizeof(u64);
	if (opp_table->clk_count != count) {
		pr_err("%s: Count mismatch between opp-hz and clk_count (%d %d)\n",
		       __func__, count, opp_table->clk_count);
		return -EINVAL;
	}

	rates = kmalloc_array(count, sizeof(*rates), GFP_KERNEL);
	if (!rates)
		return -ENOMEM;

	ret = of_property_read_u64_array(np, "opp-hz", rates, count);
	if (ret) {
		pr_err("%s: Error parsing opp-hz: %d\n", __func__, ret);
	} else {
		/*
		 * Rate is defined as an unsigned long in clk API, and so
		 * casting explicitly to its type. Must be fixed once rate is 64
		 * bit guaranteed in clk API.
		 */
		for (i = 0; i < count; i++) {
			new_opp->rates[i] = (unsigned long)rates[i];

			/* This will happen for frequencies > 4.29 GHz */
			WARN_ON(new_opp->rates[i] != rates[i]);
		}
	}

	kfree(rates);

	return ret;
}

static int _read_bw(struct dev_pm_opp *new_opp, struct opp_table *opp_table,
		    struct device_node *np, bool peak)
{
	const char *name = peak ? "opp-peak-kBps" : "opp-avg-kBps";
	struct property *prop;
	int i, count, ret;
	u32 *bw;

	prop = of_find_property(np, name, NULL);
	if (!prop)
		return -ENODEV;

	count = prop->length / sizeof(u32);
	if (opp_table->path_count != count) {
		pr_err("%s: Mismatch between %s and paths (%d %d)\n",
				__func__, name, count, opp_table->path_count);
		return -EINVAL;
	}

	bw = kmalloc_array(count, sizeof(*bw), GFP_KERNEL);
	if (!bw)
		return -ENOMEM;

	ret = of_property_read_u32_array(np, name, bw, count);
	if (ret) {
		pr_err("%s: Error parsing %s: %d\n", __func__, name, ret);
		goto out;
	}

	for (i = 0; i < count; i++) {
		if (peak)
			new_opp->bandwidth[i].peak = kBps_to_icc(bw[i]);
		else
			new_opp->bandwidth[i].avg = kBps_to_icc(bw[i]);
	}

out:
	kfree(bw);
	return ret;
}

static int _read_opp_key(struct dev_pm_opp *new_opp,
			 struct opp_table *opp_table, struct device_node *np)
{
	bool found = false;
	int ret;

	ret = _read_rate(new_opp, opp_table, np);
	if (!ret)
		found = true;
	else if (ret != -ENODEV)
		return ret;

	/*
	 * Bandwidth consists of peak and average (optional) values:
	 * opp-peak-kBps = <path1_value path2_value>;
	 * opp-avg-kBps = <path1_value path2_value>;
	 */
	ret = _read_bw(new_opp, opp_table, np, true);
	if (!ret) {
		found = true;
		ret = _read_bw(new_opp, opp_table, np, false);
	}

	/* The properties were found but we failed to parse them */
	if (ret && ret != -ENODEV)
		return ret;

	if (!of_property_read_u32(np, "opp-level", &new_opp->level))
		found = true;

	if (found)
		return 0;

	return ret;
}

/**
 * _opp_add_static_v2() - Allocate static OPPs (As per 'v2' DT bindings)
 * @opp_table:	OPP table
 * @dev:	device for which we do this operation
 * @np:		device node
 *
 * This function adds an opp definition to the opp table and returns status. The
 * opp can be controlled using dev_pm_opp_enable/disable functions and may be
 * removed by dev_pm_opp_remove.
 *
 * Return:
 * Valid OPP pointer:
 *		On success
 * NULL:
 *		Duplicate OPPs (both freq and volt are same) and opp->available
 *		OR if the OPP is not supported by hardware.
 * ERR_PTR(-EEXIST):
 *		Freq are same and volt are different OR
 *		Duplicate OPPs (both freq and volt are same) and !opp->available
 * ERR_PTR(-ENOMEM):
 *		Memory allocation failure
 * ERR_PTR(-EINVAL):
 *		Failed parsing the OPP node
 */
static struct dev_pm_opp *_opp_add_static_v2(struct opp_table *opp_table,
		struct device *dev, struct device_node *np)
{
	struct dev_pm_opp *new_opp;
	u32 val;
	int ret;

	new_opp = _opp_allocate(opp_table);
	if (!new_opp)
		return ERR_PTR(-ENOMEM);

	ret = _read_opp_key(new_opp, opp_table, np);
	if (ret < 0) {
		dev_err(dev, "%s: opp key field not found\n", __func__);
		goto free_opp;
	}

	/* Check if the OPP supports hardware's hierarchy of versions or not */
	if (!_opp_is_supported(dev, opp_table, np)) {
		dev_dbg(dev, "OPP not supported by hardware: %s\n",
			of_node_full_name(np));
		goto free_opp;
	}

	new_opp->turbo = of_property_read_bool(np, "turbo-mode");

	new_opp->np = of_node_get(np);
	new_opp->dynamic = false;
	new_opp->available = true;

	ret = _of_opp_alloc_required_opps(opp_table, new_opp);
	if (ret)
		goto free_opp;

	if (!of_property_read_u32(np, "clock-latency-ns", &val))
		new_opp->clock_latency_ns = val;

	ret = opp_parse_supplies(new_opp, dev, opp_table);
	if (ret)
		goto free_required_opps;

	ret = _opp_add(dev, new_opp, opp_table);
	if (ret) {
		/* Don't return error for duplicate OPPs */
		if (ret == -EBUSY)
			ret = 0;
		goto free_required_opps;
	}

	/* OPP to select on device suspend */
	if (of_property_read_bool(np, "opp-suspend")) {
		if (opp_table->suspend_opp) {
			/* Pick the OPP with higher rate/bw/level as suspend OPP */
			if (_opp_compare_key(opp_table, new_opp, opp_table->suspend_opp) == 1) {
				opp_table->suspend_opp->suspend = false;
				new_opp->suspend = true;
				opp_table->suspend_opp = new_opp;
			}
		} else {
			new_opp->suspend = true;
			opp_table->suspend_opp = new_opp;
		}
	}

	if (new_opp->clock_latency_ns > opp_table->clock_latency_ns_max)
		opp_table->clock_latency_ns_max = new_opp->clock_latency_ns;

	pr_debug("%s: turbo:%d rate:%lu uv:%lu uvmin:%lu uvmax:%lu latency:%lu level:%u\n",
		 __func__, new_opp->turbo, new_opp->rates[0],
		 new_opp->supplies[0].u_volt, new_opp->supplies[0].u_volt_min,
		 new_opp->supplies[0].u_volt_max, new_opp->clock_latency_ns,
		 new_opp->level);

	/*
	 * Notify the changes in the availability of the operable
	 * frequency/voltage list.
	 */
	blocking_notifier_call_chain(&opp_table->head, OPP_EVENT_ADD, new_opp);
	return new_opp;

free_required_opps:
	_of_opp_free_required_opps(opp_table, new_opp);
free_opp:
	_opp_free(new_opp);

	return ret ? ERR_PTR(ret) : NULL;
}

/* Initializes OPP tables based on new bindings */
static int _of_add_opp_table_v2(struct device *dev, struct opp_table *opp_table)
{
	struct device_node *np;
	int ret, count = 0;
	struct dev_pm_opp *opp;

	/* OPP table is already initialized for the device */
	mutex_lock(&opp_table->lock);
	if (opp_table->parsed_static_opps) {
		opp_table->parsed_static_opps++;
		mutex_unlock(&opp_table->lock);
		return 0;
	}

	opp_table->parsed_static_opps = 1;
	mutex_unlock(&opp_table->lock);

	/* We have opp-table node now, iterate over it and add OPPs */
	for_each_available_child_of_node(opp_table->np, np) {
		opp = _opp_add_static_v2(opp_table, dev, np);
		if (IS_ERR(opp)) {
			ret = PTR_ERR(opp);
			dev_err(dev, "%s: Failed to add OPP, %d\n", __func__,
				ret);
			of_node_put(np);
			goto remove_static_opp;
		} else if (opp) {
			count++;
		}
	}

	/* There should be one or more OPPs defined */
	if (!count) {
		dev_err(dev, "%s: no supported OPPs", __func__);
		ret = -ENOENT;
		goto remove_static_opp;
	}

	lazy_link_required_opp_table(opp_table);

	return 0;

remove_static_opp:
	_opp_remove_all_static(opp_table);

	return ret;
}

/* Initializes OPP tables based on old-deprecated bindings */
static int _of_add_opp_table_v1(struct device *dev, struct opp_table *opp_table)
{
	const struct property *prop;
	const __be32 *val;
	int nr, ret = 0;

	mutex_lock(&opp_table->lock);
	if (opp_table->parsed_static_opps) {
		opp_table->parsed_static_opps++;
		mutex_unlock(&opp_table->lock);
		return 0;
	}

	opp_table->parsed_static_opps = 1;
	mutex_unlock(&opp_table->lock);

	prop = of_find_property(dev->of_node, "operating-points", NULL);
	if (!prop) {
		ret = -ENODEV;
		goto remove_static_opp;
	}
	if (!prop->value) {
		ret = -ENODATA;
		goto remove_static_opp;
	}

	/*
	 * Each OPP is a set of tuples consisting of frequency and
	 * voltage like <freq-kHz vol-uV>.
	 */
	nr = prop->length / sizeof(u32);
	if (nr % 2) {
		dev_err(dev, "%s: Invalid OPP table\n", __func__);
		ret = -EINVAL;
		goto remove_static_opp;
	}

	val = prop->value;
	while (nr) {
		unsigned long freq = be32_to_cpup(val++) * 1000;
		unsigned long volt = be32_to_cpup(val++);

		ret = _opp_add_v1(opp_table, dev, freq, volt, false);
		if (ret) {
			dev_err(dev, "%s: Failed to add OPP %ld (%d)\n",
				__func__, freq, ret);
			goto remove_static_opp;
		}
		nr -= 2;
	}

	return 0;

remove_static_opp:
	_opp_remove_all_static(opp_table);

	return ret;
}

static int _of_add_table_indexed(struct device *dev, int index)
{
	struct opp_table *opp_table;
	int ret, count;

	if (index) {
		/*
		 * If only one phandle is present, then the same OPP table
		 * applies for all index requests.
		 */
		count = of_count_phandle_with_args(dev->of_node,
						   "operating-points-v2", NULL);
		if (count == 1)
			index = 0;
	}

	opp_table = _add_opp_table_indexed(dev, index, true);
	if (IS_ERR(opp_table))
		return PTR_ERR(opp_table);

	/*
	 * OPPs have two version of bindings now. Also try the old (v1)
	 * bindings for backward compatibility with older dtbs.
	 */
	if (opp_table->np)
		ret = _of_add_opp_table_v2(dev, opp_table);
	else
		ret = _of_add_opp_table_v1(dev, opp_table);

	if (ret)
		dev_pm_opp_put_opp_table(opp_table);

	return ret;
}

static void devm_pm_opp_of_table_release(void *data)
{
	dev_pm_opp_of_remove_table(data);
}

static int _devm_of_add_table_indexed(struct device *dev, int index)
{
	int ret;

	ret = _of_add_table_indexed(dev, index);
	if (ret)
		return ret;

	return devm_add_action_or_reset(dev, devm_pm_opp_of_table_release, dev);
}

/**
 * devm_pm_opp_of_add_table() - Initialize opp table from device tree
 * @dev:	device pointer used to lookup OPP table.
 *
 * Register the initial OPP table with the OPP library for given device.
 *
 * The opp_table structure will be freed after the device is destroyed.
 *
 * Return:
 * 0		On success OR
 *		Duplicate OPPs (both freq and volt are same) and opp->available
 * -EEXIST	Freq are same and volt are different OR
 *		Duplicate OPPs (both freq and volt are same) and !opp->available
 * -ENOMEM	Memory allocation failure
 * -ENODEV	when 'operating-points' property is not found or is invalid data
 *		in device node.
 * -ENODATA	when empty 'operating-points' property is found
 * -EINVAL	when invalid entries are found in opp-v2 table
 */
int devm_pm_opp_of_add_table(struct device *dev)
{
	return _devm_of_add_table_indexed(dev, 0);
}
EXPORT_SYMBOL_GPL(devm_pm_opp_of_add_table);

/**
 * dev_pm_opp_of_add_table() - Initialize opp table from device tree
 * @dev:	device pointer used to lookup OPP table.
 *
 * Register the initial OPP table with the OPP library for given device.
 *
 * Return:
 * 0		On success OR
 *		Duplicate OPPs (both freq and volt are same) and opp->available
 * -EEXIST	Freq are same and volt are different OR
 *		Duplicate OPPs (both freq and volt are same) and !opp->available
 * -ENOMEM	Memory allocation failure
 * -ENODEV	when 'operating-points' property is not found or is invalid data
 *		in device node.
 * -ENODATA	when empty 'operating-points' property is found
 * -EINVAL	when invalid entries are found in opp-v2 table
 */
int dev_pm_opp_of_add_table(struct device *dev)
{
	return _of_add_table_indexed(dev, 0);
}
EXPORT_SYMBOL_GPL(dev_pm_opp_of_add_table);

/**
 * dev_pm_opp_of_add_table_indexed() - Initialize indexed opp table from device tree
 * @dev:	device pointer used to lookup OPP table.
 * @index:	Index number.
 *
 * Register the initial OPP table with the OPP library for given device only
 * using the "operating-points-v2" property.
 *
 * Return: Refer to dev_pm_opp_of_add_table() for return values.
 */
int dev_pm_opp_of_add_table_indexed(struct device *dev, int index)
{
	return _of_add_table_indexed(dev, index);
}
EXPORT_SYMBOL_GPL(dev_pm_opp_of_add_table_indexed);

/**
 * devm_pm_opp_of_add_table_indexed() - Initialize indexed opp table from device tree
 * @dev:	device pointer used to lookup OPP table.
 * @index:	Index number.
 *
 * This is a resource-managed variant of dev_pm_opp_of_add_table_indexed().
 */
int devm_pm_opp_of_add_table_indexed(struct device *dev, int index)
{
	return _devm_of_add_table_indexed(dev, index);
}
EXPORT_SYMBOL_GPL(devm_pm_opp_of_add_table_indexed);

/* CPU device specific helpers */

/**
 * dev_pm_opp_of_cpumask_remove_table() - Removes OPP table for @cpumask
 * @cpumask:	cpumask for which OPP table needs to be removed
 *
 * This removes the OPP tables for CPUs present in the @cpumask.
 * This should be used only to remove static entries created from DT.
 */
void dev_pm_opp_of_cpumask_remove_table(const struct cpumask *cpumask)
{
	_dev_pm_opp_cpumask_remove_table(cpumask, -1);
}
EXPORT_SYMBOL_GPL(dev_pm_opp_of_cpumask_remove_table);

/**
 * dev_pm_opp_of_cpumask_add_table() - Adds OPP table for @cpumask
 * @cpumask:	cpumask for which OPP table needs to be added.
 *
 * This adds the OPP tables for CPUs present in the @cpumask.
 */
int dev_pm_opp_of_cpumask_add_table(const struct cpumask *cpumask)
{
	struct device *cpu_dev;
	int cpu, ret;

	if (WARN_ON(cpumask_empty(cpumask)))
		return -ENODEV;

	for_each_cpu(cpu, cpumask) {
		cpu_dev = get_cpu_device(cpu);
		if (!cpu_dev) {
			pr_err("%s: failed to get cpu%d device\n", __func__,
			       cpu);
			ret = -ENODEV;
			goto remove_table;
		}

		ret = dev_pm_opp_of_add_table(cpu_dev);
		if (ret) {
			/*
			 * OPP may get registered dynamically, don't print error
			 * message here.
			 */
			pr_debug("%s: couldn't find opp table for cpu:%d, %d\n",
				 __func__, cpu, ret);

			goto remove_table;
		}
	}

	return 0;

remove_table:
	/* Free all other OPPs */
	_dev_pm_opp_cpumask_remove_table(cpumask, cpu);

	return ret;
}
EXPORT_SYMBOL_GPL(dev_pm_opp_of_cpumask_add_table);

/*
 * Works only for OPP v2 bindings.
 *
 * Returns -ENOENT if operating-points-v2 bindings aren't supported.
 */
/**
 * dev_pm_opp_of_get_sharing_cpus() - Get cpumask of CPUs sharing OPPs with
 *				      @cpu_dev using operating-points-v2
 *				      bindings.
 *
 * @cpu_dev:	CPU device for which we do this operation
 * @cpumask:	cpumask to update with information of sharing CPUs
 *
 * This updates the @cpumask with CPUs that are sharing OPPs with @cpu_dev.
 *
 * Returns -ENOENT if operating-points-v2 isn't present for @cpu_dev.
 */
int dev_pm_opp_of_get_sharing_cpus(struct device *cpu_dev,
				   struct cpumask *cpumask)
{
	struct device_node *np, *tmp_np, *cpu_np;
	int cpu, ret = 0;

	/* Get OPP descriptor node */
	np = dev_pm_opp_of_get_opp_desc_node(cpu_dev);
	if (!np) {
		dev_dbg(cpu_dev, "%s: Couldn't find opp node.\n", __func__);
		return -ENOENT;
	}

	cpumask_set_cpu(cpu_dev->id, cpumask);

	/* OPPs are shared ? */
	if (!of_property_read_bool(np, "opp-shared"))
		goto put_cpu_node;

	for_each_possible_cpu(cpu) {
		if (cpu == cpu_dev->id)
			continue;

		cpu_np = of_cpu_device_node_get(cpu);
		if (!cpu_np) {
			dev_err(cpu_dev, "%s: failed to get cpu%d node\n",
				__func__, cpu);
			ret = -ENOENT;
			goto put_cpu_node;
		}

		/* Get OPP descriptor node */
		tmp_np = _opp_of_get_opp_desc_node(cpu_np, 0);
		of_node_put(cpu_np);
		if (!tmp_np) {
			pr_err("%pOF: Couldn't find opp node\n", cpu_np);
			ret = -ENOENT;
			goto put_cpu_node;
		}

		/* CPUs are sharing opp node */
		if (np == tmp_np)
			cpumask_set_cpu(cpu, cpumask);

		of_node_put(tmp_np);
	}

put_cpu_node:
	of_node_put(np);
	return ret;
}
EXPORT_SYMBOL_GPL(dev_pm_opp_of_get_sharing_cpus);

/**
 * of_get_required_opp_performance_state() - Search for required OPP and return its performance state.
 * @np: Node that contains the "required-opps" property.
 * @index: Index of the phandle to parse.
 *
 * Returns the performance state of the OPP pointed out by the "required-opps"
 * property at @index in @np.
 *
 * Return: Zero or positive performance state on success, otherwise negative
 * value on errors.
 */
int of_get_required_opp_performance_state(struct device_node *np, int index)
{
	struct dev_pm_opp *opp;
	struct device_node *required_np;
	struct opp_table *opp_table;
	int pstate = -EINVAL;

	required_np = of_parse_required_opp(np, index);
	if (!required_np)
		return -ENODEV;

	opp_table = _find_table_of_opp_np(required_np);
	if (IS_ERR(opp_table)) {
		pr_err("%s: Failed to find required OPP table %pOF: %ld\n",
		       __func__, np, PTR_ERR(opp_table));
		goto put_required_np;
	}

	/* The OPP tables must belong to a genpd */
	if (unlikely(!opp_table->is_genpd)) {
		pr_err("%s: Performance state is only valid for genpds.\n", __func__);
		goto put_required_np;
	}

	opp = _find_opp_of_np(opp_table, required_np);
	if (opp) {
		pstate = opp->level;
		dev_pm_opp_put(opp);
	}

	dev_pm_opp_put_opp_table(opp_table);

put_required_np:
	of_node_put(required_np);

	return pstate;
}
EXPORT_SYMBOL_GPL(of_get_required_opp_performance_state);

/**
 * dev_pm_opp_get_of_node() - Gets the DT node corresponding to an opp
 * @opp:	opp for which DT node has to be returned for
 *
 * Return: DT node corresponding to the opp, else 0 on success.
 *
 * The caller needs to put the node with of_node_put() after using it.
 */
struct device_node *dev_pm_opp_get_of_node(struct dev_pm_opp *opp)
{
	if (IS_ERR_OR_NULL(opp)) {
		pr_err("%s: Invalid parameters\n", __func__);
		return NULL;
	}

	return of_node_get(opp->np);
}
EXPORT_SYMBOL_GPL(dev_pm_opp_get_of_node);

/*
 * Callback function provided to the Energy Model framework upon registration.
 * It provides the power used by @dev at @kHz if it is the frequency of an
 * existing OPP, or at the frequency of the first OPP above @kHz otherwise
 * (see dev_pm_opp_find_freq_ceil()). This function updates @kHz to the ceiled
 * frequency and @uW to the associated power.
 *
 * Returns 0 on success or a proper -EINVAL value in case of error.
 */
static int __maybe_unused
_get_dt_power(struct device *dev, unsigned long *uW, unsigned long *kHz)
{
	struct dev_pm_opp *opp;
	unsigned long opp_freq, opp_power;

	/* Find the right frequency and related OPP */
	opp_freq = *kHz * 1000;
	opp = dev_pm_opp_find_freq_ceil(dev, &opp_freq);
	if (IS_ERR(opp))
		return -EINVAL;

	opp_power = dev_pm_opp_get_power(opp);
	dev_pm_opp_put(opp);
	if (!opp_power)
		return -EINVAL;

	*kHz = opp_freq / 1000;
	*uW = opp_power;

	return 0;
}

/*
 * Callback function provided to the Energy Model framework upon registration.
 * This computes the power estimated by @dev at @kHz if it is the frequency
 * of an existing OPP, or at the frequency of the first OPP above @kHz otherwise
 * (see dev_pm_opp_find_freq_ceil()). This function updates @kHz to the ceiled
 * frequency and @uW to the associated power. The power is estimated as
 * P = C * V^2 * f with C being the device's capacitance and V and f
 * respectively the voltage and frequency of the OPP.
 *
 * Returns -EINVAL if the power calculation failed because of missing
 * parameters, 0 otherwise.
 */
static int __maybe_unused _get_power(struct device *dev, unsigned long *uW,
				     unsigned long *kHz)
{
	struct dev_pm_opp *opp;
	struct device_node *np;
	unsigned long mV, Hz;
	u32 cap;
	u64 tmp;
	int ret;

	np = of_node_get(dev->of_node);
	if (!np)
		return -EINVAL;

	ret = of_property_read_u32(np, "dynamic-power-coefficient", &cap);
	of_node_put(np);
	if (ret)
		return -EINVAL;

	Hz = *kHz * 1000;
	opp = dev_pm_opp_find_freq_ceil(dev, &Hz);
	if (IS_ERR(opp))
		return -EINVAL;

	mV = dev_pm_opp_get_voltage(opp) / 1000;
	dev_pm_opp_put(opp);
	if (!mV)
		return -EINVAL;

	tmp = (u64)cap * mV * mV * (Hz / 1000000);
	/* Provide power in micro-Watts */
	do_div(tmp, 1000000);

	*uW = (unsigned long)tmp;
	*kHz = Hz / 1000;

	return 0;
}

static bool _of_has_opp_microwatt_property(struct device *dev)
{
	unsigned long power, freq = 0;
	struct dev_pm_opp *opp;

	/* Check if at least one OPP has needed property */
	opp = dev_pm_opp_find_freq_ceil(dev, &freq);
	if (IS_ERR(opp))
		return false;

	power = dev_pm_opp_get_power(opp);
	dev_pm_opp_put(opp);
	if (!power)
		return false;

	return true;
}

/**
 * dev_pm_opp_of_register_em() - Attempt to register an Energy Model
 * @dev		: Device for which an Energy Model has to be registered
 * @cpus	: CPUs for which an Energy Model has to be registered. For
 *		other type of devices it should be set to NULL.
 *
 * This checks whether the "dynamic-power-coefficient" devicetree property has
 * been specified, and tries to register an Energy Model with it if it has.
 * Having this property means the voltages are known for OPPs and the EM
 * might be calculated.
 */
int dev_pm_opp_of_register_em(struct device *dev, struct cpumask *cpus)
{
	struct em_data_callback em_cb;
	struct device_node *np;
	int ret, nr_opp;
	u32 cap;

	if (IS_ERR_OR_NULL(dev)) {
		ret = -EINVAL;
		goto failed;
	}

	nr_opp = dev_pm_opp_get_opp_count(dev);
	if (nr_opp <= 0) {
		ret = -EINVAL;
		goto failed;
	}

	/* First, try to find more precised Energy Model in DT */
	if (_of_has_opp_microwatt_property(dev)) {
		EM_SET_ACTIVE_POWER_CB(em_cb, _get_dt_power);
		goto register_em;
	}

	np = of_node_get(dev->of_node);
	if (!np) {
		ret = -EINVAL;
		goto failed;
	}

	/*
	 * Register an EM only if the 'dynamic-power-coefficient' property is
	 * set in devicetree. It is assumed the voltage values are known if that
	 * property is set since it is useless otherwise. If voltages are not
	 * known, just let the EM registration fail with an error to alert the
	 * user about the inconsistent configuration.
	 */
	ret = of_property_read_u32(np, "dynamic-power-coefficient", &cap);
	of_node_put(np);
	if (ret || !cap) {
		dev_dbg(dev, "Couldn't find proper 'dynamic-power-coefficient' in DT\n");
		ret = -EINVAL;
		goto failed;
	}

	EM_SET_ACTIVE_POWER_CB(em_cb, _get_power);

register_em:
	ret = em_dev_register_perf_domain(dev, nr_opp, &em_cb, cpus, true);
	if (ret)
		goto failed;

	return 0;

failed:
	dev_dbg(dev, "Couldn't register Energy Model %d\n", ret);
	return ret;
}
EXPORT_SYMBOL_GPL(dev_pm_opp_of_register_em);