summaryrefslogtreecommitdiff
path: root/drivers/devfreq/devfreq.c
blob: 861c100f9fac34b28725a19693d588762b7efa66 (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
1599
1600
1601
1602
1603
1604
1605
1606
1607
1608
1609
1610
1611
1612
1613
1614
1615
1616
1617
1618
1619
1620
1621
1622
1623
1624
1625
1626
1627
1628
1629
1630
1631
1632
1633
1634
1635
1636
1637
1638
1639
1640
1641
1642
1643
1644
1645
1646
1647
1648
1649
1650
1651
1652
1653
1654
1655
1656
1657
1658
1659
1660
1661
1662
1663
1664
1665
1666
1667
1668
1669
1670
1671
1672
1673
1674
1675
1676
1677
1678
1679
1680
1681
1682
1683
1684
1685
1686
1687
1688
1689
1690
1691
1692
1693
1694
1695
1696
1697
1698
1699
1700
1701
1702
1703
1704
1705
1706
1707
1708
1709
1710
1711
1712
1713
1714
1715
1716
1717
1718
1719
1720
1721
1722
1723
1724
1725
1726
1727
1728
1729
1730
1731
1732
1733
1734
1735
1736
1737
1738
1739
1740
1741
1742
1743
1744
1745
1746
1747
1748
1749
1750
1751
1752
1753
1754
1755
1756
1757
1758
1759
1760
1761
1762
1763
1764
1765
1766
1767
1768
1769
1770
1771
1772
1773
1774
1775
1776
1777
1778
1779
1780
1781
1782
1783
1784
1785
1786
1787
1788
1789
1790
1791
1792
1793
1794
1795
1796
1797
1798
1799
1800
1801
1802
1803
1804
1805
1806
1807
1808
1809
1810
1811
1812
1813
1814
1815
1816
1817
1818
1819
1820
1821
1822
1823
1824
1825
1826
1827
1828
1829
1830
1831
1832
1833
1834
1835
1836
1837
1838
1839
1840
1841
1842
1843
1844
1845
1846
1847
1848
1849
1850
1851
1852
1853
1854
1855
1856
1857
1858
1859
1860
1861
1862
1863
1864
1865
1866
1867
1868
1869
1870
1871
1872
1873
1874
1875
1876
1877
1878
1879
1880
1881
1882
1883
1884
1885
1886
1887
1888
1889
1890
1891
1892
1893
1894
1895
1896
1897
1898
1899
1900
1901
1902
1903
1904
1905
1906
1907
1908
1909
1910
1911
1912
1913
1914
1915
1916
1917
1918
1919
1920
1921
1922
1923
1924
1925
1926
1927
1928
1929
1930
1931
1932
1933
1934
1935
1936
1937
1938
1939
1940
1941
1942
1943
1944
1945
1946
1947
1948
1949
1950
1951
1952
1953
1954
1955
1956
1957
1958
1959
1960
1961
1962
1963
1964
1965
1966
1967
1968
1969
1970
1971
1972
1973
1974
1975
1976
1977
1978
1979
1980
1981
1982
1983
1984
1985
1986
1987
1988
1989
1990
1991
1992
1993
1994
1995
1996
1997
1998
1999
2000
2001
2002
2003
2004
2005
2006
2007
2008
2009
2010
2011
2012
2013
2014
2015
2016
2017
2018
2019
2020
2021
2022
2023
2024
2025
2026
2027
2028
2029
2030
2031
2032
2033
2034
2035
2036
2037
2038
2039
2040
2041
2042
2043
2044
2045
2046
2047
2048
2049
2050
2051
2052
2053
2054
2055
2056
2057
2058
2059
2060
2061
2062
2063
2064
2065
2066
2067
2068
2069
2070
2071
2072
2073
2074
2075
2076
2077
2078
2079
2080
2081
2082
2083
2084
2085
2086
2087
2088
2089
2090
2091
2092
2093
2094
2095
2096
2097
2098
2099
2100
2101
2102
2103
2104
2105
2106
2107
2108
2109
2110
2111
2112
2113
2114
2115
2116
2117
2118
2119
2120
2121
// SPDX-License-Identifier: GPL-2.0-only
/*
 * devfreq: Generic Dynamic Voltage and Frequency Scaling (DVFS) Framework
 *	    for Non-CPU Devices.
 *
 * Copyright (C) 2011 Samsung Electronics
 *	MyungJoo Ham <myungjoo.ham@samsung.com>
 */

#include <linux/kernel.h>
#include <linux/kmod.h>
#include <linux/sched.h>
#include <linux/debugfs.h>
#include <linux/errno.h>
#include <linux/err.h>
#include <linux/init.h>
#include <linux/export.h>
#include <linux/slab.h>
#include <linux/stat.h>
#include <linux/pm_opp.h>
#include <linux/devfreq.h>
#include <linux/workqueue.h>
#include <linux/platform_device.h>
#include <linux/list.h>
#include <linux/printk.h>
#include <linux/hrtimer.h>
#include <linux/of.h>
#include <linux/pm_qos.h>
#include "governor.h"

#define CREATE_TRACE_POINTS
#include <trace/events/devfreq.h>

#define HZ_PER_KHZ	1000

static struct class *devfreq_class;
static struct dentry *devfreq_debugfs;

/*
 * devfreq core provides delayed work based load monitoring helper
 * functions. Governors can use these or can implement their own
 * monitoring mechanism.
 */
static struct workqueue_struct *devfreq_wq;

/* The list of all device-devfreq governors */
static LIST_HEAD(devfreq_governor_list);
/* The list of all device-devfreq */
static LIST_HEAD(devfreq_list);
static DEFINE_MUTEX(devfreq_list_lock);

static const char timer_name[][DEVFREQ_NAME_LEN] = {
	[DEVFREQ_TIMER_DEFERRABLE] = { "deferrable" },
	[DEVFREQ_TIMER_DELAYED] = { "delayed" },
};

/**
 * find_device_devfreq() - find devfreq struct using device pointer
 * @dev:	device pointer used to lookup device devfreq.
 *
 * Search the list of device devfreqs and return the matched device's
 * devfreq info. devfreq_list_lock should be held by the caller.
 */
static struct devfreq *find_device_devfreq(struct device *dev)
{
	struct devfreq *tmp_devfreq;

	lockdep_assert_held(&devfreq_list_lock);

	if (IS_ERR_OR_NULL(dev)) {
		pr_err("DEVFREQ: %s: Invalid parameters\n", __func__);
		return ERR_PTR(-EINVAL);
	}

	list_for_each_entry(tmp_devfreq, &devfreq_list, node) {
		if (tmp_devfreq->dev.parent == dev)
			return tmp_devfreq;
	}

	return ERR_PTR(-ENODEV);
}

static unsigned long find_available_min_freq(struct devfreq *devfreq)
{
	struct dev_pm_opp *opp;
	unsigned long min_freq = 0;

	opp = dev_pm_opp_find_freq_ceil(devfreq->dev.parent, &min_freq);
	if (IS_ERR(opp))
		min_freq = 0;
	else
		dev_pm_opp_put(opp);

	return min_freq;
}

static unsigned long find_available_max_freq(struct devfreq *devfreq)
{
	struct dev_pm_opp *opp;
	unsigned long max_freq = ULONG_MAX;

	opp = dev_pm_opp_find_freq_floor(devfreq->dev.parent, &max_freq);
	if (IS_ERR(opp))
		max_freq = 0;
	else
		dev_pm_opp_put(opp);

	return max_freq;
}

/**
 * get_freq_range() - Get the current freq range
 * @devfreq:	the devfreq instance
 * @min_freq:	the min frequency
 * @max_freq:	the max frequency
 *
 * This takes into consideration all constraints.
 */
static void get_freq_range(struct devfreq *devfreq,
			   unsigned long *min_freq,
			   unsigned long *max_freq)
{
	unsigned long *freq_table = devfreq->profile->freq_table;
	s32 qos_min_freq, qos_max_freq;

	lockdep_assert_held(&devfreq->lock);

	/*
	 * Initialize minimum/maximum frequency from freq table.
	 * The devfreq drivers can initialize this in either ascending or
	 * descending order and devfreq core supports both.
	 */
	if (freq_table[0] < freq_table[devfreq->profile->max_state - 1]) {
		*min_freq = freq_table[0];
		*max_freq = freq_table[devfreq->profile->max_state - 1];
	} else {
		*min_freq = freq_table[devfreq->profile->max_state - 1];
		*max_freq = freq_table[0];
	}

	/* Apply constraints from PM QoS */
	qos_min_freq = dev_pm_qos_read_value(devfreq->dev.parent,
					     DEV_PM_QOS_MIN_FREQUENCY);
	qos_max_freq = dev_pm_qos_read_value(devfreq->dev.parent,
					     DEV_PM_QOS_MAX_FREQUENCY);
	*min_freq = max(*min_freq, (unsigned long)HZ_PER_KHZ * qos_min_freq);
	if (qos_max_freq != PM_QOS_MAX_FREQUENCY_DEFAULT_VALUE)
		*max_freq = min(*max_freq,
				(unsigned long)HZ_PER_KHZ * qos_max_freq);

	/* Apply constraints from OPP interface */
	*min_freq = max(*min_freq, devfreq->scaling_min_freq);
	*max_freq = min(*max_freq, devfreq->scaling_max_freq);

	if (*min_freq > *max_freq)
		*min_freq = *max_freq;
}

/**
 * devfreq_get_freq_level() - Lookup freq_table for the frequency
 * @devfreq:	the devfreq instance
 * @freq:	the target frequency
 */
static int devfreq_get_freq_level(struct devfreq *devfreq, unsigned long freq)
{
	int lev;

	for (lev = 0; lev < devfreq->profile->max_state; lev++)
		if (freq == devfreq->profile->freq_table[lev])
			return lev;

	return -EINVAL;
}

static int set_freq_table(struct devfreq *devfreq)
{
	struct devfreq_dev_profile *profile = devfreq->profile;
	struct dev_pm_opp *opp;
	unsigned long freq;
	int i, count;

	/* Initialize the freq_table from OPP table */
	count = dev_pm_opp_get_opp_count(devfreq->dev.parent);
	if (count <= 0)
		return -EINVAL;

	profile->max_state = count;
	profile->freq_table = devm_kcalloc(devfreq->dev.parent,
					profile->max_state,
					sizeof(*profile->freq_table),
					GFP_KERNEL);
	if (!profile->freq_table) {
		profile->max_state = 0;
		return -ENOMEM;
	}

	for (i = 0, freq = 0; i < profile->max_state; i++, freq++) {
		opp = dev_pm_opp_find_freq_ceil(devfreq->dev.parent, &freq);
		if (IS_ERR(opp)) {
			devm_kfree(devfreq->dev.parent, profile->freq_table);
			profile->max_state = 0;
			return PTR_ERR(opp);
		}
		dev_pm_opp_put(opp);
		profile->freq_table[i] = freq;
	}

	return 0;
}

/**
 * devfreq_update_status() - Update statistics of devfreq behavior
 * @devfreq:	the devfreq instance
 * @freq:	the update target frequency
 */
int devfreq_update_status(struct devfreq *devfreq, unsigned long freq)
{
	int lev, prev_lev, ret = 0;
	u64 cur_time;

	lockdep_assert_held(&devfreq->lock);
	cur_time = get_jiffies_64();

	/* Immediately exit if previous_freq is not initialized yet. */
	if (!devfreq->previous_freq)
		goto out;

	prev_lev = devfreq_get_freq_level(devfreq, devfreq->previous_freq);
	if (prev_lev < 0) {
		ret = prev_lev;
		goto out;
	}

	devfreq->stats.time_in_state[prev_lev] +=
			cur_time - devfreq->stats.last_update;

	lev = devfreq_get_freq_level(devfreq, freq);
	if (lev < 0) {
		ret = lev;
		goto out;
	}

	if (lev != prev_lev) {
		devfreq->stats.trans_table[
			(prev_lev * devfreq->profile->max_state) + lev]++;
		devfreq->stats.total_trans++;
	}

out:
	devfreq->stats.last_update = cur_time;
	return ret;
}
EXPORT_SYMBOL(devfreq_update_status);

/**
 * find_devfreq_governor() - find devfreq governor from name
 * @name:	name of the governor
 *
 * Search the list of devfreq governors and return the matched
 * governor's pointer. devfreq_list_lock should be held by the caller.
 */
static struct devfreq_governor *find_devfreq_governor(const char *name)
{
	struct devfreq_governor *tmp_governor;

	lockdep_assert_held(&devfreq_list_lock);

	if (IS_ERR_OR_NULL(name)) {
		pr_err("DEVFREQ: %s: Invalid parameters\n", __func__);
		return ERR_PTR(-EINVAL);
	}

	list_for_each_entry(tmp_governor, &devfreq_governor_list, node) {
		if (!strncmp(tmp_governor->name, name, DEVFREQ_NAME_LEN))
			return tmp_governor;
	}

	return ERR_PTR(-ENODEV);
}

/**
 * try_then_request_governor() - Try to find the governor and request the
 *                               module if is not found.
 * @name:	name of the governor
 *
 * Search the list of devfreq governors and request the module and try again
 * if is not found. This can happen when both drivers (the governor driver
 * and the driver that call devfreq_add_device) are built as modules.
 * devfreq_list_lock should be held by the caller. Returns the matched
 * governor's pointer or an error pointer.
 */
static struct devfreq_governor *try_then_request_governor(const char *name)
{
	struct devfreq_governor *governor;
	int err = 0;

	lockdep_assert_held(&devfreq_list_lock);

	if (IS_ERR_OR_NULL(name)) {
		pr_err("DEVFREQ: %s: Invalid parameters\n", __func__);
		return ERR_PTR(-EINVAL);
	}

	governor = find_devfreq_governor(name);
	if (IS_ERR(governor)) {
		mutex_unlock(&devfreq_list_lock);

		if (!strncmp(name, DEVFREQ_GOV_SIMPLE_ONDEMAND,
			     DEVFREQ_NAME_LEN))
			err = request_module("governor_%s", "simpleondemand");
		else
			err = request_module("governor_%s", name);
		/* Restore previous state before return */
		mutex_lock(&devfreq_list_lock);
		if (err)
			return (err < 0) ? ERR_PTR(err) : ERR_PTR(-EINVAL);

		governor = find_devfreq_governor(name);
	}

	return governor;
}

static int devfreq_notify_transition(struct devfreq *devfreq,
		struct devfreq_freqs *freqs, unsigned int state)
{
	if (!devfreq)
		return -EINVAL;

	switch (state) {
	case DEVFREQ_PRECHANGE:
		srcu_notifier_call_chain(&devfreq->transition_notifier_list,
				DEVFREQ_PRECHANGE, freqs);
		break;

	case DEVFREQ_POSTCHANGE:
		srcu_notifier_call_chain(&devfreq->transition_notifier_list,
				DEVFREQ_POSTCHANGE, freqs);
		break;
	default:
		return -EINVAL;
	}

	return 0;
}

static int devfreq_set_target(struct devfreq *devfreq, unsigned long new_freq,
			      u32 flags)
{
	struct devfreq_freqs freqs;
	unsigned long cur_freq;
	int err = 0;

	if (devfreq->profile->get_cur_freq)
		devfreq->profile->get_cur_freq(devfreq->dev.parent, &cur_freq);
	else
		cur_freq = devfreq->previous_freq;

	freqs.old = cur_freq;
	freqs.new = new_freq;
	devfreq_notify_transition(devfreq, &freqs, DEVFREQ_PRECHANGE);

	err = devfreq->profile->target(devfreq->dev.parent, &new_freq, flags);
	if (err) {
		freqs.new = cur_freq;
		devfreq_notify_transition(devfreq, &freqs, DEVFREQ_POSTCHANGE);
		return err;
	}

	freqs.new = new_freq;
	devfreq_notify_transition(devfreq, &freqs, DEVFREQ_POSTCHANGE);

	if (devfreq_update_status(devfreq, new_freq))
		dev_err(&devfreq->dev,
			"Couldn't update frequency transition information.\n");

	devfreq->previous_freq = new_freq;

	if (devfreq->suspend_freq)
		devfreq->resume_freq = cur_freq;

	return err;
}

/* Load monitoring helper functions for governors use */

/**
 * update_devfreq() - Reevaluate the device and configure frequency.
 * @devfreq:	the devfreq instance.
 *
 * Note: Lock devfreq->lock before calling update_devfreq
 *	 This function is exported for governors.
 */
int update_devfreq(struct devfreq *devfreq)
{
	unsigned long freq, min_freq, max_freq;
	int err = 0;
	u32 flags = 0;

	lockdep_assert_held(&devfreq->lock);

	if (!devfreq->governor)
		return -EINVAL;

	/* Reevaluate the proper frequency */
	err = devfreq->governor->get_target_freq(devfreq, &freq);
	if (err)
		return err;
	get_freq_range(devfreq, &min_freq, &max_freq);

	if (freq < min_freq) {
		freq = min_freq;
		flags &= ~DEVFREQ_FLAG_LEAST_UPPER_BOUND; /* Use GLB */
	}
	if (freq > max_freq) {
		freq = max_freq;
		flags |= DEVFREQ_FLAG_LEAST_UPPER_BOUND; /* Use LUB */
	}

	return devfreq_set_target(devfreq, freq, flags);

}
EXPORT_SYMBOL(update_devfreq);

/**
 * devfreq_monitor() - Periodically poll devfreq objects.
 * @work:	the work struct used to run devfreq_monitor periodically.
 *
 */
static void devfreq_monitor(struct work_struct *work)
{
	int err;
	struct devfreq *devfreq = container_of(work,
					struct devfreq, work.work);

	mutex_lock(&devfreq->lock);
	err = update_devfreq(devfreq);
	if (err)
		dev_err(&devfreq->dev, "dvfs failed with (%d) error\n", err);

	queue_delayed_work(devfreq_wq, &devfreq->work,
				msecs_to_jiffies(devfreq->profile->polling_ms));
	mutex_unlock(&devfreq->lock);

	trace_devfreq_monitor(devfreq);
}

/**
 * devfreq_monitor_start() - Start load monitoring of devfreq instance
 * @devfreq:	the devfreq instance.
 *
 * Helper function for starting devfreq device load monitoring. By
 * default delayed work based monitoring is supported. Function
 * to be called from governor in response to DEVFREQ_GOV_START
 * event when device is added to devfreq framework.
 */
void devfreq_monitor_start(struct devfreq *devfreq)
{
	if (devfreq->governor->interrupt_driven)
		return;

	switch (devfreq->profile->timer) {
	case DEVFREQ_TIMER_DEFERRABLE:
		INIT_DEFERRABLE_WORK(&devfreq->work, devfreq_monitor);
		break;
	case DEVFREQ_TIMER_DELAYED:
		INIT_DELAYED_WORK(&devfreq->work, devfreq_monitor);
		break;
	default:
		return;
	}

	if (devfreq->profile->polling_ms)
		queue_delayed_work(devfreq_wq, &devfreq->work,
			msecs_to_jiffies(devfreq->profile->polling_ms));
}
EXPORT_SYMBOL(devfreq_monitor_start);

/**
 * devfreq_monitor_stop() - Stop load monitoring of a devfreq instance
 * @devfreq:	the devfreq instance.
 *
 * Helper function to stop devfreq device load monitoring. Function
 * to be called from governor in response to DEVFREQ_GOV_STOP
 * event when device is removed from devfreq framework.
 */
void devfreq_monitor_stop(struct devfreq *devfreq)
{
	if (devfreq->governor->interrupt_driven)
		return;

	cancel_delayed_work_sync(&devfreq->work);
}
EXPORT_SYMBOL(devfreq_monitor_stop);

/**
 * devfreq_monitor_suspend() - Suspend load monitoring of a devfreq instance
 * @devfreq:	the devfreq instance.
 *
 * Helper function to suspend devfreq device load monitoring. Function
 * to be called from governor in response to DEVFREQ_GOV_SUSPEND
 * event or when polling interval is set to zero.
 *
 * Note: Though this function is same as devfreq_monitor_stop(),
 * intentionally kept separate to provide hooks for collecting
 * transition statistics.
 */
void devfreq_monitor_suspend(struct devfreq *devfreq)
{
	mutex_lock(&devfreq->lock);
	if (devfreq->stop_polling) {
		mutex_unlock(&devfreq->lock);
		return;
	}

	devfreq_update_status(devfreq, devfreq->previous_freq);
	devfreq->stop_polling = true;
	mutex_unlock(&devfreq->lock);

	if (devfreq->governor->interrupt_driven)
		return;

	cancel_delayed_work_sync(&devfreq->work);
}
EXPORT_SYMBOL(devfreq_monitor_suspend);

/**
 * devfreq_monitor_resume() - Resume load monitoring of a devfreq instance
 * @devfreq:    the devfreq instance.
 *
 * Helper function to resume devfreq device load monitoring. Function
 * to be called from governor in response to DEVFREQ_GOV_RESUME
 * event or when polling interval is set to non-zero.
 */
void devfreq_monitor_resume(struct devfreq *devfreq)
{
	unsigned long freq;

	mutex_lock(&devfreq->lock);
	if (!devfreq->stop_polling)
		goto out;

	if (devfreq->governor->interrupt_driven)
		goto out_update;

	if (!delayed_work_pending(&devfreq->work) &&
			devfreq->profile->polling_ms)
		queue_delayed_work(devfreq_wq, &devfreq->work,
			msecs_to_jiffies(devfreq->profile->polling_ms));

out_update:
	devfreq->stats.last_update = get_jiffies_64();
	devfreq->stop_polling = false;

	if (devfreq->profile->get_cur_freq &&
		!devfreq->profile->get_cur_freq(devfreq->dev.parent, &freq))
		devfreq->previous_freq = freq;

out:
	mutex_unlock(&devfreq->lock);
}
EXPORT_SYMBOL(devfreq_monitor_resume);

/**
 * devfreq_update_interval() - Update device devfreq monitoring interval
 * @devfreq:    the devfreq instance.
 * @delay:      new polling interval to be set.
 *
 * Helper function to set new load monitoring polling interval. Function
 * to be called from governor in response to DEVFREQ_GOV_UPDATE_INTERVAL event.
 */
void devfreq_update_interval(struct devfreq *devfreq, unsigned int *delay)
{
	unsigned int cur_delay = devfreq->profile->polling_ms;
	unsigned int new_delay = *delay;

	mutex_lock(&devfreq->lock);
	devfreq->profile->polling_ms = new_delay;

	if (devfreq->stop_polling)
		goto out;

	if (devfreq->governor->interrupt_driven)
		goto out;

	/* if new delay is zero, stop polling */
	if (!new_delay) {
		mutex_unlock(&devfreq->lock);
		cancel_delayed_work_sync(&devfreq->work);
		return;
	}

	/* if current delay is zero, start polling with new delay */
	if (!cur_delay) {
		queue_delayed_work(devfreq_wq, &devfreq->work,
			msecs_to_jiffies(devfreq->profile->polling_ms));
		goto out;
	}

	/* if current delay is greater than new delay, restart polling */
	if (cur_delay > new_delay) {
		mutex_unlock(&devfreq->lock);
		cancel_delayed_work_sync(&devfreq->work);
		mutex_lock(&devfreq->lock);
		if (!devfreq->stop_polling)
			queue_delayed_work(devfreq_wq, &devfreq->work,
				msecs_to_jiffies(devfreq->profile->polling_ms));
	}
out:
	mutex_unlock(&devfreq->lock);
}
EXPORT_SYMBOL(devfreq_update_interval);

/**
 * devfreq_notifier_call() - Notify that the device frequency requirements
 *			     has been changed out of devfreq framework.
 * @nb:		the notifier_block (supposed to be devfreq->nb)
 * @type:	not used
 * @devp:	not used
 *
 * Called by a notifier that uses devfreq->nb.
 */
static int devfreq_notifier_call(struct notifier_block *nb, unsigned long type,
				 void *devp)
{
	struct devfreq *devfreq = container_of(nb, struct devfreq, nb);
	int err = -EINVAL;

	mutex_lock(&devfreq->lock);

	devfreq->scaling_min_freq = find_available_min_freq(devfreq);
	if (!devfreq->scaling_min_freq)
		goto out;

	devfreq->scaling_max_freq = find_available_max_freq(devfreq);
	if (!devfreq->scaling_max_freq) {
		devfreq->scaling_max_freq = ULONG_MAX;
		goto out;
	}

	err = update_devfreq(devfreq);

out:
	mutex_unlock(&devfreq->lock);
	if (err)
		dev_err(devfreq->dev.parent,
			"failed to update frequency from OPP notifier (%d)\n",
			err);

	return NOTIFY_OK;
}

/**
 * qos_notifier_call() - Common handler for QoS constraints.
 * @devfreq:    the devfreq instance.
 */
static int qos_notifier_call(struct devfreq *devfreq)
{
	int err;

	mutex_lock(&devfreq->lock);
	err = update_devfreq(devfreq);
	mutex_unlock(&devfreq->lock);
	if (err)
		dev_err(devfreq->dev.parent,
			"failed to update frequency from PM QoS (%d)\n",
			err);

	return NOTIFY_OK;
}

/**
 * qos_min_notifier_call() - Callback for QoS min_freq changes.
 * @nb:		Should be devfreq->nb_min
 */
static int qos_min_notifier_call(struct notifier_block *nb,
					 unsigned long val, void *ptr)
{
	return qos_notifier_call(container_of(nb, struct devfreq, nb_min));
}

/**
 * qos_max_notifier_call() - Callback for QoS max_freq changes.
 * @nb:		Should be devfreq->nb_max
 */
static int qos_max_notifier_call(struct notifier_block *nb,
					 unsigned long val, void *ptr)
{
	return qos_notifier_call(container_of(nb, struct devfreq, nb_max));
}

/**
 * devfreq_dev_release() - Callback for struct device to release the device.
 * @dev:	the devfreq device
 *
 * Remove devfreq from the list and release its resources.
 */
static void devfreq_dev_release(struct device *dev)
{
	struct devfreq *devfreq = to_devfreq(dev);
	int err;

	mutex_lock(&devfreq_list_lock);
	list_del(&devfreq->node);
	mutex_unlock(&devfreq_list_lock);

	err = dev_pm_qos_remove_notifier(devfreq->dev.parent, &devfreq->nb_max,
					 DEV_PM_QOS_MAX_FREQUENCY);
	if (err && err != -ENOENT)
		dev_warn(dev->parent,
			"Failed to remove max_freq notifier: %d\n", err);
	err = dev_pm_qos_remove_notifier(devfreq->dev.parent, &devfreq->nb_min,
					 DEV_PM_QOS_MIN_FREQUENCY);
	if (err && err != -ENOENT)
		dev_warn(dev->parent,
			"Failed to remove min_freq notifier: %d\n", err);

	if (dev_pm_qos_request_active(&devfreq->user_max_freq_req)) {
		err = dev_pm_qos_remove_request(&devfreq->user_max_freq_req);
		if (err < 0)
			dev_warn(dev->parent,
				"Failed to remove max_freq request: %d\n", err);
	}
	if (dev_pm_qos_request_active(&devfreq->user_min_freq_req)) {
		err = dev_pm_qos_remove_request(&devfreq->user_min_freq_req);
		if (err < 0)
			dev_warn(dev->parent,
				"Failed to remove min_freq request: %d\n", err);
	}

	if (devfreq->profile->exit)
		devfreq->profile->exit(devfreq->dev.parent);

	mutex_destroy(&devfreq->lock);
	kfree(devfreq);
}

/**
 * devfreq_add_device() - Add devfreq feature to the device
 * @dev:	the device to add devfreq feature.
 * @profile:	device-specific profile to run devfreq.
 * @governor_name:	name of the policy to choose frequency.
 * @data:	private data for the governor. The devfreq framework does not
 *		touch this value.
 */
struct devfreq *devfreq_add_device(struct device *dev,
				   struct devfreq_dev_profile *profile,
				   const char *governor_name,
				   void *data)
{
	struct devfreq *devfreq;
	struct devfreq_governor *governor;
	int err = 0;

	if (!dev || !profile || !governor_name) {
		dev_err(dev, "%s: Invalid parameters.\n", __func__);
		return ERR_PTR(-EINVAL);
	}

	mutex_lock(&devfreq_list_lock);
	devfreq = find_device_devfreq(dev);
	mutex_unlock(&devfreq_list_lock);
	if (!IS_ERR(devfreq)) {
		dev_err(dev, "%s: devfreq device already exists!\n",
			__func__);
		err = -EINVAL;
		goto err_out;
	}

	devfreq = kzalloc(sizeof(struct devfreq), GFP_KERNEL);
	if (!devfreq) {
		err = -ENOMEM;
		goto err_out;
	}

	mutex_init(&devfreq->lock);
	mutex_lock(&devfreq->lock);
	devfreq->dev.parent = dev;
	devfreq->dev.class = devfreq_class;
	devfreq->dev.release = devfreq_dev_release;
	INIT_LIST_HEAD(&devfreq->node);
	devfreq->profile = profile;
	strscpy(devfreq->governor_name, governor_name, DEVFREQ_NAME_LEN);
	devfreq->previous_freq = profile->initial_freq;
	devfreq->last_status.current_frequency = profile->initial_freq;
	devfreq->data = data;
	devfreq->nb.notifier_call = devfreq_notifier_call;

	if (devfreq->profile->timer < 0
		|| devfreq->profile->timer >= DEVFREQ_TIMER_NUM) {
		goto err_out;
	}

	if (!devfreq->profile->max_state && !devfreq->profile->freq_table) {
		mutex_unlock(&devfreq->lock);
		err = set_freq_table(devfreq);
		if (err < 0)
			goto err_dev;
		mutex_lock(&devfreq->lock);
	}

	devfreq->scaling_min_freq = find_available_min_freq(devfreq);
	if (!devfreq->scaling_min_freq) {
		mutex_unlock(&devfreq->lock);
		err = -EINVAL;
		goto err_dev;
	}

	devfreq->scaling_max_freq = find_available_max_freq(devfreq);
	if (!devfreq->scaling_max_freq) {
		mutex_unlock(&devfreq->lock);
		err = -EINVAL;
		goto err_dev;
	}

	devfreq->suspend_freq = dev_pm_opp_get_suspend_opp_freq(dev);
	atomic_set(&devfreq->suspend_count, 0);

	dev_set_name(&devfreq->dev, "%s", dev_name(dev));
	err = device_register(&devfreq->dev);
	if (err) {
		mutex_unlock(&devfreq->lock);
		put_device(&devfreq->dev);
		goto err_out;
	}

	devfreq->stats.trans_table = devm_kzalloc(&devfreq->dev,
			array3_size(sizeof(unsigned int),
				    devfreq->profile->max_state,
				    devfreq->profile->max_state),
			GFP_KERNEL);
	if (!devfreq->stats.trans_table) {
		mutex_unlock(&devfreq->lock);
		err = -ENOMEM;
		goto err_devfreq;
	}

	devfreq->stats.time_in_state = devm_kcalloc(&devfreq->dev,
			devfreq->profile->max_state,
			sizeof(*devfreq->stats.time_in_state),
			GFP_KERNEL);
	if (!devfreq->stats.time_in_state) {
		mutex_unlock(&devfreq->lock);
		err = -ENOMEM;
		goto err_devfreq;
	}

	devfreq->stats.total_trans = 0;
	devfreq->stats.last_update = get_jiffies_64();

	srcu_init_notifier_head(&devfreq->transition_notifier_list);

	mutex_unlock(&devfreq->lock);

	err = dev_pm_qos_add_request(dev, &devfreq->user_min_freq_req,
				     DEV_PM_QOS_MIN_FREQUENCY, 0);
	if (err < 0)
		goto err_devfreq;
	err = dev_pm_qos_add_request(dev, &devfreq->user_max_freq_req,
				     DEV_PM_QOS_MAX_FREQUENCY,
				     PM_QOS_MAX_FREQUENCY_DEFAULT_VALUE);
	if (err < 0)
		goto err_devfreq;

	devfreq->nb_min.notifier_call = qos_min_notifier_call;
	err = dev_pm_qos_add_notifier(devfreq->dev.parent, &devfreq->nb_min,
				      DEV_PM_QOS_MIN_FREQUENCY);
	if (err)
		goto err_devfreq;

	devfreq->nb_max.notifier_call = qos_max_notifier_call;
	err = dev_pm_qos_add_notifier(devfreq->dev.parent, &devfreq->nb_max,
				      DEV_PM_QOS_MAX_FREQUENCY);
	if (err)
		goto err_devfreq;

	mutex_lock(&devfreq_list_lock);

	governor = try_then_request_governor(devfreq->governor_name);
	if (IS_ERR(governor)) {
		dev_err(dev, "%s: Unable to find governor for the device\n",
			__func__);
		err = PTR_ERR(governor);
		goto err_init;
	}

	devfreq->governor = governor;
	err = devfreq->governor->event_handler(devfreq, DEVFREQ_GOV_START,
						NULL);
	if (err) {
		dev_err(dev, "%s: Unable to start governor for the device\n",
			__func__);
		goto err_init;
	}

	list_add(&devfreq->node, &devfreq_list);

	mutex_unlock(&devfreq_list_lock);

	return devfreq;

err_init:
	mutex_unlock(&devfreq_list_lock);
err_devfreq:
	devfreq_remove_device(devfreq);
	devfreq = NULL;
err_dev:
	kfree(devfreq);
err_out:
	return ERR_PTR(err);
}
EXPORT_SYMBOL(devfreq_add_device);

/**
 * devfreq_remove_device() - Remove devfreq feature from a device.
 * @devfreq:	the devfreq instance to be removed
 *
 * The opposite of devfreq_add_device().
 */
int devfreq_remove_device(struct devfreq *devfreq)
{
	if (!devfreq)
		return -EINVAL;

	if (devfreq->governor)
		devfreq->governor->event_handler(devfreq,
						 DEVFREQ_GOV_STOP, NULL);
	device_unregister(&devfreq->dev);

	return 0;
}
EXPORT_SYMBOL(devfreq_remove_device);

static int devm_devfreq_dev_match(struct device *dev, void *res, void *data)
{
	struct devfreq **r = res;

	if (WARN_ON(!r || !*r))
		return 0;

	return *r == data;
}

static void devm_devfreq_dev_release(struct device *dev, void *res)
{
	devfreq_remove_device(*(struct devfreq **)res);
}

/**
 * devm_devfreq_add_device() - Resource-managed devfreq_add_device()
 * @dev:	the device to add devfreq feature.
 * @profile:	device-specific profile to run devfreq.
 * @governor_name:	name of the policy to choose frequency.
 * @data:	private data for the governor. The devfreq framework does not
 *		touch this value.
 *
 * This function manages automatically the memory of devfreq device using device
 * resource management and simplify the free operation for memory of devfreq
 * device.
 */
struct devfreq *devm_devfreq_add_device(struct device *dev,
					struct devfreq_dev_profile *profile,
					const char *governor_name,
					void *data)
{
	struct devfreq **ptr, *devfreq;

	ptr = devres_alloc(devm_devfreq_dev_release, sizeof(*ptr), GFP_KERNEL);
	if (!ptr)
		return ERR_PTR(-ENOMEM);

	devfreq = devfreq_add_device(dev, profile, governor_name, data);
	if (IS_ERR(devfreq)) {
		devres_free(ptr);
		return devfreq;
	}

	*ptr = devfreq;
	devres_add(dev, ptr);

	return devfreq;
}
EXPORT_SYMBOL(devm_devfreq_add_device);

#ifdef CONFIG_OF
/*
 * devfreq_get_devfreq_by_node - Get the devfreq device from devicetree
 * @node - pointer to device_node
 *
 * return the instance of devfreq device
 */
struct devfreq *devfreq_get_devfreq_by_node(struct device_node *node)
{
	struct devfreq *devfreq;

	if (!node)
		return ERR_PTR(-EINVAL);

	mutex_lock(&devfreq_list_lock);
	list_for_each_entry(devfreq, &devfreq_list, node) {
		if (devfreq->dev.parent
			&& devfreq->dev.parent->of_node == node) {
			mutex_unlock(&devfreq_list_lock);
			return devfreq;
		}
	}
	mutex_unlock(&devfreq_list_lock);

	return ERR_PTR(-ENODEV);
}

/*
 * devfreq_get_devfreq_by_phandle - Get the devfreq device from devicetree
 * @dev - instance to the given device
 * @phandle_name - name of property holding a phandle value
 * @index - index into list of devfreq
 *
 * return the instance of devfreq device
 */
struct devfreq *devfreq_get_devfreq_by_phandle(struct device *dev,
					const char *phandle_name, int index)
{
	struct device_node *node;
	struct devfreq *devfreq;

	if (!dev || !phandle_name)
		return ERR_PTR(-EINVAL);

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

	node = of_parse_phandle(dev->of_node, phandle_name, index);
	if (!node)
		return ERR_PTR(-ENODEV);

	devfreq = devfreq_get_devfreq_by_node(node);
	of_node_put(node);

	return devfreq;
}

#else
struct devfreq *devfreq_get_devfreq_by_node(struct device_node *node)
{
	return ERR_PTR(-ENODEV);
}

struct devfreq *devfreq_get_devfreq_by_phandle(struct device *dev,
					const char *phandle_name, int index)
{
	return ERR_PTR(-ENODEV);
}
#endif /* CONFIG_OF */
EXPORT_SYMBOL_GPL(devfreq_get_devfreq_by_node);
EXPORT_SYMBOL_GPL(devfreq_get_devfreq_by_phandle);

/**
 * devm_devfreq_remove_device() - Resource-managed devfreq_remove_device()
 * @dev:	the device from which to remove devfreq feature.
 * @devfreq:	the devfreq instance to be removed
 */
void devm_devfreq_remove_device(struct device *dev, struct devfreq *devfreq)
{
	WARN_ON(devres_release(dev, devm_devfreq_dev_release,
			       devm_devfreq_dev_match, devfreq));
}
EXPORT_SYMBOL(devm_devfreq_remove_device);

/**
 * devfreq_suspend_device() - Suspend devfreq of a device.
 * @devfreq: the devfreq instance to be suspended
 *
 * This function is intended to be called by the pm callbacks
 * (e.g., runtime_suspend, suspend) of the device driver that
 * holds the devfreq.
 */
int devfreq_suspend_device(struct devfreq *devfreq)
{
	int ret;

	if (!devfreq)
		return -EINVAL;

	if (atomic_inc_return(&devfreq->suspend_count) > 1)
		return 0;

	if (devfreq->governor) {
		ret = devfreq->governor->event_handler(devfreq,
					DEVFREQ_GOV_SUSPEND, NULL);
		if (ret)
			return ret;
	}

	if (devfreq->suspend_freq) {
		mutex_lock(&devfreq->lock);
		ret = devfreq_set_target(devfreq, devfreq->suspend_freq, 0);
		mutex_unlock(&devfreq->lock);
		if (ret)
			return ret;
	}

	return 0;
}
EXPORT_SYMBOL(devfreq_suspend_device);

/**
 * devfreq_resume_device() - Resume devfreq of a device.
 * @devfreq: the devfreq instance to be resumed
 *
 * This function is intended to be called by the pm callbacks
 * (e.g., runtime_resume, resume) of the device driver that
 * holds the devfreq.
 */
int devfreq_resume_device(struct devfreq *devfreq)
{
	int ret;

	if (!devfreq)
		return -EINVAL;

	if (atomic_dec_return(&devfreq->suspend_count) >= 1)
		return 0;

	if (devfreq->resume_freq) {
		mutex_lock(&devfreq->lock);
		ret = devfreq_set_target(devfreq, devfreq->resume_freq, 0);
		mutex_unlock(&devfreq->lock);
		if (ret)
			return ret;
	}

	if (devfreq->governor) {
		ret = devfreq->governor->event_handler(devfreq,
					DEVFREQ_GOV_RESUME, NULL);
		if (ret)
			return ret;
	}

	return 0;
}
EXPORT_SYMBOL(devfreq_resume_device);

/**
 * devfreq_suspend() - Suspend devfreq governors and devices
 *
 * Called during system wide Suspend/Hibernate cycles for suspending governors
 * and devices preserving the state for resume. On some platforms the devfreq
 * device must have precise state (frequency) after resume in order to provide
 * fully operating setup.
 */
void devfreq_suspend(void)
{
	struct devfreq *devfreq;
	int ret;

	mutex_lock(&devfreq_list_lock);
	list_for_each_entry(devfreq, &devfreq_list, node) {
		ret = devfreq_suspend_device(devfreq);
		if (ret)
			dev_err(&devfreq->dev,
				"failed to suspend devfreq device\n");
	}
	mutex_unlock(&devfreq_list_lock);
}

/**
 * devfreq_resume() - Resume devfreq governors and devices
 *
 * Called during system wide Suspend/Hibernate cycle for resuming governors and
 * devices that are suspended with devfreq_suspend().
 */
void devfreq_resume(void)
{
	struct devfreq *devfreq;
	int ret;

	mutex_lock(&devfreq_list_lock);
	list_for_each_entry(devfreq, &devfreq_list, node) {
		ret = devfreq_resume_device(devfreq);
		if (ret)
			dev_warn(&devfreq->dev,
				 "failed to resume devfreq device\n");
	}
	mutex_unlock(&devfreq_list_lock);
}

/**
 * devfreq_add_governor() - Add devfreq governor
 * @governor:	the devfreq governor to be added
 */
int devfreq_add_governor(struct devfreq_governor *governor)
{
	struct devfreq_governor *g;
	struct devfreq *devfreq;
	int err = 0;

	if (!governor) {
		pr_err("%s: Invalid parameters.\n", __func__);
		return -EINVAL;
	}

	mutex_lock(&devfreq_list_lock);
	g = find_devfreq_governor(governor->name);
	if (!IS_ERR(g)) {
		pr_err("%s: governor %s already registered\n", __func__,
		       g->name);
		err = -EINVAL;
		goto err_out;
	}

	list_add(&governor->node, &devfreq_governor_list);

	list_for_each_entry(devfreq, &devfreq_list, node) {
		int ret = 0;
		struct device *dev = devfreq->dev.parent;

		if (!strncmp(devfreq->governor_name, governor->name,
			     DEVFREQ_NAME_LEN)) {
			/* The following should never occur */
			if (devfreq->governor) {
				dev_warn(dev,
					 "%s: Governor %s already present\n",
					 __func__, devfreq->governor->name);
				ret = devfreq->governor->event_handler(devfreq,
							DEVFREQ_GOV_STOP, NULL);
				if (ret) {
					dev_warn(dev,
						 "%s: Governor %s stop = %d\n",
						 __func__,
						 devfreq->governor->name, ret);
				}
				/* Fall through */
			}
			devfreq->governor = governor;
			ret = devfreq->governor->event_handler(devfreq,
						DEVFREQ_GOV_START, NULL);
			if (ret) {
				dev_warn(dev, "%s: Governor %s start=%d\n",
					 __func__, devfreq->governor->name,
					 ret);
			}
		}
	}

err_out:
	mutex_unlock(&devfreq_list_lock);

	return err;
}
EXPORT_SYMBOL(devfreq_add_governor);

/**
 * devfreq_remove_governor() - Remove devfreq feature from a device.
 * @governor:	the devfreq governor to be removed
 */
int devfreq_remove_governor(struct devfreq_governor *governor)
{
	struct devfreq_governor *g;
	struct devfreq *devfreq;
	int err = 0;

	if (!governor) {
		pr_err("%s: Invalid parameters.\n", __func__);
		return -EINVAL;
	}

	mutex_lock(&devfreq_list_lock);
	g = find_devfreq_governor(governor->name);
	if (IS_ERR(g)) {
		pr_err("%s: governor %s not registered\n", __func__,
		       governor->name);
		err = PTR_ERR(g);
		goto err_out;
	}
	list_for_each_entry(devfreq, &devfreq_list, node) {
		int ret;
		struct device *dev = devfreq->dev.parent;

		if (!strncmp(devfreq->governor_name, governor->name,
			     DEVFREQ_NAME_LEN)) {
			/* we should have a devfreq governor! */
			if (!devfreq->governor) {
				dev_warn(dev, "%s: Governor %s NOT present\n",
					 __func__, governor->name);
				continue;
				/* Fall through */
			}
			ret = devfreq->governor->event_handler(devfreq,
						DEVFREQ_GOV_STOP, NULL);
			if (ret) {
				dev_warn(dev, "%s: Governor %s stop=%d\n",
					 __func__, devfreq->governor->name,
					 ret);
			}
			devfreq->governor = NULL;
		}
	}

	list_del(&governor->node);
err_out:
	mutex_unlock(&devfreq_list_lock);

	return err;
}
EXPORT_SYMBOL(devfreq_remove_governor);

static ssize_t name_show(struct device *dev,
			struct device_attribute *attr, char *buf)
{
	struct devfreq *df = to_devfreq(dev);
	return sprintf(buf, "%s\n", dev_name(df->dev.parent));
}
static DEVICE_ATTR_RO(name);

static ssize_t governor_show(struct device *dev,
			     struct device_attribute *attr, char *buf)
{
	struct devfreq *df = to_devfreq(dev);

	if (!df->governor)
		return -EINVAL;

	return sprintf(buf, "%s\n", df->governor->name);
}

static ssize_t governor_store(struct device *dev, struct device_attribute *attr,
			      const char *buf, size_t count)
{
	struct devfreq *df = to_devfreq(dev);
	int ret;
	char str_governor[DEVFREQ_NAME_LEN + 1];
	const struct devfreq_governor *governor, *prev_governor;

	if (!df->governor)
		return -EINVAL;

	ret = sscanf(buf, "%" __stringify(DEVFREQ_NAME_LEN) "s", str_governor);
	if (ret != 1)
		return -EINVAL;

	mutex_lock(&devfreq_list_lock);
	governor = try_then_request_governor(str_governor);
	if (IS_ERR(governor)) {
		ret = PTR_ERR(governor);
		goto out;
	}
	if (df->governor == governor) {
		ret = 0;
		goto out;
	} else if (df->governor->immutable || governor->immutable) {
		ret = -EINVAL;
		goto out;
	}

	ret = df->governor->event_handler(df, DEVFREQ_GOV_STOP, NULL);
	if (ret) {
		dev_warn(dev, "%s: Governor %s not stopped(%d)\n",
			 __func__, df->governor->name, ret);
		goto out;
	}

	prev_governor = df->governor;
	df->governor = governor;
	strncpy(df->governor_name, governor->name, DEVFREQ_NAME_LEN);
	ret = df->governor->event_handler(df, DEVFREQ_GOV_START, NULL);
	if (ret) {
		dev_warn(dev, "%s: Governor %s not started(%d)\n",
			 __func__, df->governor->name, ret);
		df->governor = prev_governor;
		strncpy(df->governor_name, prev_governor->name,
			DEVFREQ_NAME_LEN);
		ret = df->governor->event_handler(df, DEVFREQ_GOV_START, NULL);
		if (ret) {
			dev_err(dev,
				"%s: reverting to Governor %s failed (%d)\n",
				__func__, df->governor_name, ret);
			df->governor = NULL;
		}
	}
out:
	mutex_unlock(&devfreq_list_lock);

	if (!ret)
		ret = count;
	return ret;
}
static DEVICE_ATTR_RW(governor);

static ssize_t available_governors_show(struct device *d,
					struct device_attribute *attr,
					char *buf)
{
	struct devfreq *df = to_devfreq(d);
	ssize_t count = 0;

	if (!df->governor)
		return -EINVAL;

	mutex_lock(&devfreq_list_lock);

	/*
	 * The devfreq with immutable governor (e.g., passive) shows
	 * only own governor.
	 */
	if (df->governor->immutable) {
		count = scnprintf(&buf[count], DEVFREQ_NAME_LEN,
				  "%s ", df->governor_name);
	/*
	 * The devfreq device shows the registered governor except for
	 * immutable governors such as passive governor .
	 */
	} else {
		struct devfreq_governor *governor;

		list_for_each_entry(governor, &devfreq_governor_list, node) {
			if (governor->immutable)
				continue;
			count += scnprintf(&buf[count], (PAGE_SIZE - count - 2),
					   "%s ", governor->name);
		}
	}

	mutex_unlock(&devfreq_list_lock);

	/* Truncate the trailing space */
	if (count)
		count--;

	count += sprintf(&buf[count], "\n");

	return count;
}
static DEVICE_ATTR_RO(available_governors);

static ssize_t cur_freq_show(struct device *dev, struct device_attribute *attr,
			     char *buf)
{
	unsigned long freq;
	struct devfreq *df = to_devfreq(dev);

	if (!df->profile)
		return -EINVAL;

	if (df->profile->get_cur_freq &&
		!df->profile->get_cur_freq(df->dev.parent, &freq))
		return sprintf(buf, "%lu\n", freq);

	return sprintf(buf, "%lu\n", df->previous_freq);
}
static DEVICE_ATTR_RO(cur_freq);

static ssize_t target_freq_show(struct device *dev,
				struct device_attribute *attr, char *buf)
{
	struct devfreq *df = to_devfreq(dev);

	return sprintf(buf, "%lu\n", df->previous_freq);
}
static DEVICE_ATTR_RO(target_freq);

static ssize_t polling_interval_show(struct device *dev,
				     struct device_attribute *attr, char *buf)
{
	struct devfreq *df = to_devfreq(dev);

	if (!df->profile)
		return -EINVAL;

	return sprintf(buf, "%d\n", df->profile->polling_ms);
}

static ssize_t polling_interval_store(struct device *dev,
				      struct device_attribute *attr,
				      const char *buf, size_t count)
{
	struct devfreq *df = to_devfreq(dev);
	unsigned int value;
	int ret;

	if (!df->governor)
		return -EINVAL;

	ret = sscanf(buf, "%u", &value);
	if (ret != 1)
		return -EINVAL;

	df->governor->event_handler(df, DEVFREQ_GOV_UPDATE_INTERVAL, &value);
	ret = count;

	return ret;
}
static DEVICE_ATTR_RW(polling_interval);

static ssize_t min_freq_store(struct device *dev, struct device_attribute *attr,
			      const char *buf, size_t count)
{
	struct devfreq *df = to_devfreq(dev);
	unsigned long value;
	int ret;

	/*
	 * Protect against theoretical sysfs writes between
	 * device_add and dev_pm_qos_add_request
	 */
	if (!dev_pm_qos_request_active(&df->user_min_freq_req))
		return -EAGAIN;

	ret = sscanf(buf, "%lu", &value);
	if (ret != 1)
		return -EINVAL;

	/* Round down to kHz for PM QoS */
	ret = dev_pm_qos_update_request(&df->user_min_freq_req,
					value / HZ_PER_KHZ);
	if (ret < 0)
		return ret;

	return count;
}

static ssize_t min_freq_show(struct device *dev, struct device_attribute *attr,
			     char *buf)
{
	struct devfreq *df = to_devfreq(dev);
	unsigned long min_freq, max_freq;

	mutex_lock(&df->lock);
	get_freq_range(df, &min_freq, &max_freq);
	mutex_unlock(&df->lock);

	return sprintf(buf, "%lu\n", min_freq);
}
static DEVICE_ATTR_RW(min_freq);

static ssize_t max_freq_store(struct device *dev, struct device_attribute *attr,
			      const char *buf, size_t count)
{
	struct devfreq *df = to_devfreq(dev);
	unsigned long value;
	int ret;

	/*
	 * Protect against theoretical sysfs writes between
	 * device_add and dev_pm_qos_add_request
	 */
	if (!dev_pm_qos_request_active(&df->user_max_freq_req))
		return -EINVAL;

	ret = sscanf(buf, "%lu", &value);
	if (ret != 1)
		return -EINVAL;

	/*
	 * PM QoS frequencies are in kHz so we need to convert. Convert by
	 * rounding upwards so that the acceptable interval never shrinks.
	 *
	 * For example if the user writes "666666666" to sysfs this value will
	 * be converted to 666667 kHz and back to 666667000 Hz before an OPP
	 * lookup, this ensures that an OPP of 666666666Hz is still accepted.
	 *
	 * A value of zero means "no limit".
	 */
	if (value)
		value = DIV_ROUND_UP(value, HZ_PER_KHZ);
	else
		value = PM_QOS_MAX_FREQUENCY_DEFAULT_VALUE;

	ret = dev_pm_qos_update_request(&df->user_max_freq_req, value);
	if (ret < 0)
		return ret;

	return count;
}

static ssize_t max_freq_show(struct device *dev, struct device_attribute *attr,
			     char *buf)
{
	struct devfreq *df = to_devfreq(dev);
	unsigned long min_freq, max_freq;

	mutex_lock(&df->lock);
	get_freq_range(df, &min_freq, &max_freq);
	mutex_unlock(&df->lock);

	return sprintf(buf, "%lu\n", max_freq);
}
static DEVICE_ATTR_RW(max_freq);

static ssize_t available_frequencies_show(struct device *d,
					  struct device_attribute *attr,
					  char *buf)
{
	struct devfreq *df = to_devfreq(d);
	ssize_t count = 0;
	int i;

	if (!df->profile)
		return -EINVAL;

	mutex_lock(&df->lock);

	for (i = 0; i < df->profile->max_state; i++)
		count += scnprintf(&buf[count], (PAGE_SIZE - count - 2),
				"%lu ", df->profile->freq_table[i]);

	mutex_unlock(&df->lock);
	/* Truncate the trailing space */
	if (count)
		count--;

	count += sprintf(&buf[count], "\n");

	return count;
}
static DEVICE_ATTR_RO(available_frequencies);

static ssize_t trans_stat_show(struct device *dev,
			       struct device_attribute *attr, char *buf)
{
	struct devfreq *df = to_devfreq(dev);
	ssize_t len;
	int i, j;
	unsigned int max_state;

	if (!df->profile)
		return -EINVAL;
	max_state = df->profile->max_state;

	if (max_state == 0)
		return sprintf(buf, "Not Supported.\n");

	mutex_lock(&df->lock);
	if (!df->stop_polling &&
			devfreq_update_status(df, df->previous_freq)) {
		mutex_unlock(&df->lock);
		return 0;
	}
	mutex_unlock(&df->lock);

	len = sprintf(buf, "     From  :   To\n");
	len += sprintf(buf + len, "           :");
	for (i = 0; i < max_state; i++)
		len += sprintf(buf + len, "%10lu",
				df->profile->freq_table[i]);

	len += sprintf(buf + len, "   time(ms)\n");

	for (i = 0; i < max_state; i++) {
		if (df->profile->freq_table[i]
					== df->previous_freq) {
			len += sprintf(buf + len, "*");
		} else {
			len += sprintf(buf + len, " ");
		}
		len += sprintf(buf + len, "%10lu:",
				df->profile->freq_table[i]);
		for (j = 0; j < max_state; j++)
			len += sprintf(buf + len, "%10u",
				df->stats.trans_table[(i * max_state) + j]);

		len += sprintf(buf + len, "%10llu\n", (u64)
			jiffies64_to_msecs(df->stats.time_in_state[i]));
	}

	len += sprintf(buf + len, "Total transition : %u\n",
					df->stats.total_trans);
	return len;
}

static ssize_t trans_stat_store(struct device *dev,
				struct device_attribute *attr,
				const char *buf, size_t count)
{
	struct devfreq *df = to_devfreq(dev);
	int err, value;

	if (!df->profile)
		return -EINVAL;

	if (df->profile->max_state == 0)
		return count;

	err = kstrtoint(buf, 10, &value);
	if (err || value != 0)
		return -EINVAL;

	mutex_lock(&df->lock);
	memset(df->stats.time_in_state, 0, (df->profile->max_state *
					sizeof(*df->stats.time_in_state)));
	memset(df->stats.trans_table, 0, array3_size(sizeof(unsigned int),
					df->profile->max_state,
					df->profile->max_state));
	df->stats.total_trans = 0;
	df->stats.last_update = get_jiffies_64();
	mutex_unlock(&df->lock);

	return count;
}
static DEVICE_ATTR_RW(trans_stat);

static ssize_t timer_show(struct device *dev,
			     struct device_attribute *attr, char *buf)
{
	struct devfreq *df = to_devfreq(dev);

	if (!df->profile)
		return -EINVAL;

	return sprintf(buf, "%s\n", timer_name[df->profile->timer]);
}

static ssize_t timer_store(struct device *dev, struct device_attribute *attr,
			      const char *buf, size_t count)
{
	struct devfreq *df = to_devfreq(dev);
	char str_timer[DEVFREQ_NAME_LEN + 1];
	int timer = -1;
	int ret = 0, i;

	if (!df->governor || !df->profile)
		return -EINVAL;

	ret = sscanf(buf, "%16s", str_timer);
	if (ret != 1)
		return -EINVAL;

	for (i = 0; i < DEVFREQ_TIMER_NUM; i++) {
		if (!strncmp(timer_name[i], str_timer, DEVFREQ_NAME_LEN)) {
			timer = i;
			break;
		}
	}

	if (timer < 0) {
		ret = -EINVAL;
		goto out;
	}

	if (df->profile->timer == timer) {
		ret = 0;
		goto out;
	}

	mutex_lock(&df->lock);
	df->profile->timer = timer;
	mutex_unlock(&df->lock);

	ret = df->governor->event_handler(df, DEVFREQ_GOV_STOP, NULL);
	if (ret) {
		dev_warn(dev, "%s: Governor %s not stopped(%d)\n",
			 __func__, df->governor->name, ret);
		goto out;
	}

	ret = df->governor->event_handler(df, DEVFREQ_GOV_START, NULL);
	if (ret)
		dev_warn(dev, "%s: Governor %s not started(%d)\n",
			 __func__, df->governor->name, ret);
out:
	return ret ? ret : count;
}
static DEVICE_ATTR_RW(timer);

static struct attribute *devfreq_attrs[] = {
	&dev_attr_name.attr,
	&dev_attr_governor.attr,
	&dev_attr_available_governors.attr,
	&dev_attr_cur_freq.attr,
	&dev_attr_available_frequencies.attr,
	&dev_attr_target_freq.attr,
	&dev_attr_polling_interval.attr,
	&dev_attr_min_freq.attr,
	&dev_attr_max_freq.attr,
	&dev_attr_trans_stat.attr,
	&dev_attr_timer.attr,
	NULL,
};
ATTRIBUTE_GROUPS(devfreq);

/**
 * devfreq_summary_show() - Show the summary of the devfreq devices
 * @s:		seq_file instance to show the summary of devfreq devices
 * @data:	not used
 *
 * Show the summary of the devfreq devices via 'devfreq_summary' debugfs file.
 * It helps that user can know the detailed information of the devfreq devices.
 *
 * Return 0 always because it shows the information without any data change.
 */
static int devfreq_summary_show(struct seq_file *s, void *data)
{
	struct devfreq *devfreq;
	struct devfreq *p_devfreq = NULL;
	unsigned long cur_freq, min_freq, max_freq;
	unsigned int polling_ms;
	unsigned int timer;

	seq_printf(s, "%-30s %-30s %-15s %-10s %10s %12s %12s %12s\n",
			"dev",
			"parent_dev",
			"governor",
			"timer",
			"polling_ms",
			"cur_freq_Hz",
			"min_freq_Hz",
			"max_freq_Hz");
	seq_printf(s, "%30s %30s %15s %10s %10s %12s %12s %12s\n",
			"------------------------------",
			"------------------------------",
			"---------------",
			"----------",
			"----------",
			"------------",
			"------------",
			"------------");

	mutex_lock(&devfreq_list_lock);

	list_for_each_entry_reverse(devfreq, &devfreq_list, node) {
#if IS_ENABLED(CONFIG_DEVFREQ_GOV_PASSIVE)
		if (!strncmp(devfreq->governor_name, DEVFREQ_GOV_PASSIVE,
							DEVFREQ_NAME_LEN)) {
			struct devfreq_passive_data *data = devfreq->data;

			if (data)
				p_devfreq = data->parent;
		} else {
			p_devfreq = NULL;
		}
#endif

		mutex_lock(&devfreq->lock);
		cur_freq = devfreq->previous_freq;
		get_freq_range(devfreq, &min_freq, &max_freq);
		polling_ms = devfreq->profile->polling_ms;
		timer = devfreq->profile->timer;
		mutex_unlock(&devfreq->lock);

		seq_printf(s,
			"%-30s %-30s %-15s %-10s %10d %12ld %12ld %12ld\n",
			dev_name(&devfreq->dev),
			p_devfreq ? dev_name(&p_devfreq->dev) : "null",
			devfreq->governor_name,
			polling_ms ? timer_name[timer] : "null",
			polling_ms,
			cur_freq,
			min_freq,
			max_freq);
	}

	mutex_unlock(&devfreq_list_lock);

	return 0;
}
DEFINE_SHOW_ATTRIBUTE(devfreq_summary);

static int __init devfreq_init(void)
{
	devfreq_class = class_create(THIS_MODULE, "devfreq");
	if (IS_ERR(devfreq_class)) {
		pr_err("%s: couldn't create class\n", __FILE__);
		return PTR_ERR(devfreq_class);
	}

	devfreq_wq = create_freezable_workqueue("devfreq_wq");
	if (!devfreq_wq) {
		class_destroy(devfreq_class);
		pr_err("%s: couldn't create workqueue\n", __FILE__);
		return -ENOMEM;
	}
	devfreq_class->dev_groups = devfreq_groups;

	devfreq_debugfs = debugfs_create_dir("devfreq", NULL);
	debugfs_create_file("devfreq_summary", 0444,
				devfreq_debugfs, NULL,
				&devfreq_summary_fops);

	return 0;
}
subsys_initcall(devfreq_init);

/*
 * The following are helper functions for devfreq user device drivers with
 * OPP framework.
 */

/**
 * devfreq_recommended_opp() - Helper function to get proper OPP for the
 *			     freq value given to target callback.
 * @dev:	The devfreq user device. (parent of devfreq)
 * @freq:	The frequency given to target function
 * @flags:	Flags handed from devfreq framework.
 *
 * The callers are required to call dev_pm_opp_put() for the returned OPP after
 * use.
 */
struct dev_pm_opp *devfreq_recommended_opp(struct device *dev,
					   unsigned long *freq,
					   u32 flags)
{
	struct dev_pm_opp *opp;

	if (flags & DEVFREQ_FLAG_LEAST_UPPER_BOUND) {
		/* The freq is an upper bound. opp should be lower */
		opp = dev_pm_opp_find_freq_floor(dev, freq);

		/* If not available, use the closest opp */
		if (opp == ERR_PTR(-ERANGE))
			opp = dev_pm_opp_find_freq_ceil(dev, freq);
	} else {
		/* The freq is an lower bound. opp should be higher */
		opp = dev_pm_opp_find_freq_ceil(dev, freq);

		/* If not available, use the closest opp */
		if (opp == ERR_PTR(-ERANGE))
			opp = dev_pm_opp_find_freq_floor(dev, freq);
	}

	return opp;
}
EXPORT_SYMBOL(devfreq_recommended_opp);

/**
 * devfreq_register_opp_notifier() - Helper function to get devfreq notified
 *				     for any changes in the OPP availability
 *				     changes
 * @dev:	The devfreq user device. (parent of devfreq)
 * @devfreq:	The devfreq object.
 */
int devfreq_register_opp_notifier(struct device *dev, struct devfreq *devfreq)
{
	return dev_pm_opp_register_notifier(dev, &devfreq->nb);
}
EXPORT_SYMBOL(devfreq_register_opp_notifier);

/**
 * devfreq_unregister_opp_notifier() - Helper function to stop getting devfreq
 *				       notified for any changes in the OPP
 *				       availability changes anymore.
 * @dev:	The devfreq user device. (parent of devfreq)
 * @devfreq:	The devfreq object.
 *
 * At exit() callback of devfreq_dev_profile, this must be included if
 * devfreq_recommended_opp is used.
 */
int devfreq_unregister_opp_notifier(struct device *dev, struct devfreq *devfreq)
{
	return dev_pm_opp_unregister_notifier(dev, &devfreq->nb);
}
EXPORT_SYMBOL(devfreq_unregister_opp_notifier);

static void devm_devfreq_opp_release(struct device *dev, void *res)
{
	devfreq_unregister_opp_notifier(dev, *(struct devfreq **)res);
}

/**
 * devm_devfreq_register_opp_notifier() - Resource-managed
 *					  devfreq_register_opp_notifier()
 * @dev:	The devfreq user device. (parent of devfreq)
 * @devfreq:	The devfreq object.
 */
int devm_devfreq_register_opp_notifier(struct device *dev,
				       struct devfreq *devfreq)
{
	struct devfreq **ptr;
	int ret;

	ptr = devres_alloc(devm_devfreq_opp_release, sizeof(*ptr), GFP_KERNEL);
	if (!ptr)
		return -ENOMEM;

	ret = devfreq_register_opp_notifier(dev, devfreq);
	if (ret) {
		devres_free(ptr);
		return ret;
	}

	*ptr = devfreq;
	devres_add(dev, ptr);

	return 0;
}
EXPORT_SYMBOL(devm_devfreq_register_opp_notifier);

/**
 * devm_devfreq_unregister_opp_notifier() - Resource-managed
 *					    devfreq_unregister_opp_notifier()
 * @dev:	The devfreq user device. (parent of devfreq)
 * @devfreq:	The devfreq object.
 */
void devm_devfreq_unregister_opp_notifier(struct device *dev,
					 struct devfreq *devfreq)
{
	WARN_ON(devres_release(dev, devm_devfreq_opp_release,
			       devm_devfreq_dev_match, devfreq));
}
EXPORT_SYMBOL(devm_devfreq_unregister_opp_notifier);

/**
 * devfreq_register_notifier() - Register a driver with devfreq
 * @devfreq:	The devfreq object.
 * @nb:		The notifier block to register.
 * @list:	DEVFREQ_TRANSITION_NOTIFIER.
 */
int devfreq_register_notifier(struct devfreq *devfreq,
			      struct notifier_block *nb,
			      unsigned int list)
{
	int ret = 0;

	if (!devfreq)
		return -EINVAL;

	switch (list) {
	case DEVFREQ_TRANSITION_NOTIFIER:
		ret = srcu_notifier_chain_register(
				&devfreq->transition_notifier_list, nb);
		break;
	default:
		ret = -EINVAL;
	}

	return ret;
}
EXPORT_SYMBOL(devfreq_register_notifier);

/*
 * devfreq_unregister_notifier() - Unregister a driver with devfreq
 * @devfreq:	The devfreq object.
 * @nb:		The notifier block to be unregistered.
 * @list:	DEVFREQ_TRANSITION_NOTIFIER.
 */
int devfreq_unregister_notifier(struct devfreq *devfreq,
				struct notifier_block *nb,
				unsigned int list)
{
	int ret = 0;

	if (!devfreq)
		return -EINVAL;

	switch (list) {
	case DEVFREQ_TRANSITION_NOTIFIER:
		ret = srcu_notifier_chain_unregister(
				&devfreq->transition_notifier_list, nb);
		break;
	default:
		ret = -EINVAL;
	}

	return ret;
}
EXPORT_SYMBOL(devfreq_unregister_notifier);

struct devfreq_notifier_devres {
	struct devfreq *devfreq;
	struct notifier_block *nb;
	unsigned int list;
};

static void devm_devfreq_notifier_release(struct device *dev, void *res)
{
	struct devfreq_notifier_devres *this = res;

	devfreq_unregister_notifier(this->devfreq, this->nb, this->list);
}

/**
 * devm_devfreq_register_notifier()
 *	- Resource-managed devfreq_register_notifier()
 * @dev:	The devfreq user device. (parent of devfreq)
 * @devfreq:	The devfreq object.
 * @nb:		The notifier block to be unregistered.
 * @list:	DEVFREQ_TRANSITION_NOTIFIER.
 */
int devm_devfreq_register_notifier(struct device *dev,
				struct devfreq *devfreq,
				struct notifier_block *nb,
				unsigned int list)
{
	struct devfreq_notifier_devres *ptr;
	int ret;

	ptr = devres_alloc(devm_devfreq_notifier_release, sizeof(*ptr),
				GFP_KERNEL);
	if (!ptr)
		return -ENOMEM;

	ret = devfreq_register_notifier(devfreq, nb, list);
	if (ret) {
		devres_free(ptr);
		return ret;
	}

	ptr->devfreq = devfreq;
	ptr->nb = nb;
	ptr->list = list;
	devres_add(dev, ptr);

	return 0;
}
EXPORT_SYMBOL(devm_devfreq_register_notifier);

/**
 * devm_devfreq_unregister_notifier()
 *	- Resource-managed devfreq_unregister_notifier()
 * @dev:	The devfreq user device. (parent of devfreq)
 * @devfreq:	The devfreq object.
 * @nb:		The notifier block to be unregistered.
 * @list:	DEVFREQ_TRANSITION_NOTIFIER.
 */
void devm_devfreq_unregister_notifier(struct device *dev,
				      struct devfreq *devfreq,
				      struct notifier_block *nb,
				      unsigned int list)
{
	WARN_ON(devres_release(dev, devm_devfreq_notifier_release,
			       devm_devfreq_dev_match, devfreq));
}
EXPORT_SYMBOL(devm_devfreq_unregister_notifier);