summaryrefslogtreecommitdiff
path: root/drivers/nvmem/core.c
blob: 2c6b99402df8a76011c2165fb8841ae2ff7fcc1f (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
2122
2123
2124
2125
2126
2127
2128
2129
2130
2131
2132
2133
2134
2135
2136
2137
2138
2139
2140
2141
2142
2143
2144
2145
2146
2147
2148
2149
2150
2151
2152
2153
2154
2155
2156
2157
2158
2159
2160
2161
2162
2163
2164
2165
2166
2167
2168
2169
2170
2171
2172
2173
2174
2175
2176
2177
2178
2179
2180
2181
2182
2183
2184
2185
2186
2187
2188
2189
2190
2191
2192
2193
2194
2195
2196
2197
2198
2199
2200
2201
2202
2203
2204
2205
2206
2207
2208
2209
2210
2211
// SPDX-License-Identifier: GPL-2.0
/*
 * nvmem framework core.
 *
 * Copyright (C) 2015 Srinivas Kandagatla <srinivas.kandagatla@linaro.org>
 * Copyright (C) 2013 Maxime Ripard <maxime.ripard@free-electrons.com>
 */

#include <linux/device.h>
#include <linux/export.h>
#include <linux/fs.h>
#include <linux/idr.h>
#include <linux/init.h>
#include <linux/kref.h>
#include <linux/module.h>
#include <linux/nvmem-consumer.h>
#include <linux/nvmem-provider.h>
#include <linux/gpio/consumer.h>
#include <linux/of.h>
#include <linux/slab.h>

#include "internals.h"

#define to_nvmem_device(d) container_of(d, struct nvmem_device, dev)

#define FLAG_COMPAT		BIT(0)
struct nvmem_cell_entry {
	const char		*name;
	int			offset;
	size_t			raw_len;
	int			bytes;
	int			bit_offset;
	int			nbits;
	nvmem_cell_post_process_t read_post_process;
	void			*priv;
	struct device_node	*np;
	struct nvmem_device	*nvmem;
	struct list_head	node;
};

struct nvmem_cell {
	struct nvmem_cell_entry *entry;
	const char		*id;
	int			index;
};

static DEFINE_MUTEX(nvmem_mutex);
static DEFINE_IDA(nvmem_ida);

static DEFINE_MUTEX(nvmem_cell_mutex);
static LIST_HEAD(nvmem_cell_tables);

static DEFINE_MUTEX(nvmem_lookup_mutex);
static LIST_HEAD(nvmem_lookup_list);

static BLOCKING_NOTIFIER_HEAD(nvmem_notifier);

static int __nvmem_reg_read(struct nvmem_device *nvmem, unsigned int offset,
			    void *val, size_t bytes)
{
	if (nvmem->reg_read)
		return nvmem->reg_read(nvmem->priv, offset, val, bytes);

	return -EINVAL;
}

static int __nvmem_reg_write(struct nvmem_device *nvmem, unsigned int offset,
			     void *val, size_t bytes)
{
	int ret;

	if (nvmem->reg_write) {
		gpiod_set_value_cansleep(nvmem->wp_gpio, 0);
		ret = nvmem->reg_write(nvmem->priv, offset, val, bytes);
		gpiod_set_value_cansleep(nvmem->wp_gpio, 1);
		return ret;
	}

	return -EINVAL;
}

static int nvmem_access_with_keepouts(struct nvmem_device *nvmem,
				      unsigned int offset, void *val,
				      size_t bytes, int write)
{

	unsigned int end = offset + bytes;
	unsigned int kend, ksize;
	const struct nvmem_keepout *keepout = nvmem->keepout;
	const struct nvmem_keepout *keepoutend = keepout + nvmem->nkeepout;
	int rc;

	/*
	 * Skip all keepouts before the range being accessed.
	 * Keepouts are sorted.
	 */
	while ((keepout < keepoutend) && (keepout->end <= offset))
		keepout++;

	while ((offset < end) && (keepout < keepoutend)) {
		/* Access the valid portion before the keepout. */
		if (offset < keepout->start) {
			kend = min(end, keepout->start);
			ksize = kend - offset;
			if (write)
				rc = __nvmem_reg_write(nvmem, offset, val, ksize);
			else
				rc = __nvmem_reg_read(nvmem, offset, val, ksize);

			if (rc)
				return rc;

			offset += ksize;
			val += ksize;
		}

		/*
		 * Now we're aligned to the start of this keepout zone. Go
		 * through it.
		 */
		kend = min(end, keepout->end);
		ksize = kend - offset;
		if (!write)
			memset(val, keepout->value, ksize);

		val += ksize;
		offset += ksize;
		keepout++;
	}

	/*
	 * If we ran out of keepouts but there's still stuff to do, send it
	 * down directly
	 */
	if (offset < end) {
		ksize = end - offset;
		if (write)
			return __nvmem_reg_write(nvmem, offset, val, ksize);
		else
			return __nvmem_reg_read(nvmem, offset, val, ksize);
	}

	return 0;
}

static int nvmem_reg_read(struct nvmem_device *nvmem, unsigned int offset,
			  void *val, size_t bytes)
{
	if (!nvmem->nkeepout)
		return __nvmem_reg_read(nvmem, offset, val, bytes);

	return nvmem_access_with_keepouts(nvmem, offset, val, bytes, false);
}

static int nvmem_reg_write(struct nvmem_device *nvmem, unsigned int offset,
			   void *val, size_t bytes)
{
	if (!nvmem->nkeepout)
		return __nvmem_reg_write(nvmem, offset, val, bytes);

	return nvmem_access_with_keepouts(nvmem, offset, val, bytes, true);
}

#ifdef CONFIG_NVMEM_SYSFS
static const char * const nvmem_type_str[] = {
	[NVMEM_TYPE_UNKNOWN] = "Unknown",
	[NVMEM_TYPE_EEPROM] = "EEPROM",
	[NVMEM_TYPE_OTP] = "OTP",
	[NVMEM_TYPE_BATTERY_BACKED] = "Battery backed",
	[NVMEM_TYPE_FRAM] = "FRAM",
};

#ifdef CONFIG_DEBUG_LOCK_ALLOC
static struct lock_class_key eeprom_lock_key;
#endif

static ssize_t type_show(struct device *dev,
			 struct device_attribute *attr, char *buf)
{
	struct nvmem_device *nvmem = to_nvmem_device(dev);

	return sprintf(buf, "%s\n", nvmem_type_str[nvmem->type]);
}

static DEVICE_ATTR_RO(type);

static struct attribute *nvmem_attrs[] = {
	&dev_attr_type.attr,
	NULL,
};

static ssize_t bin_attr_nvmem_read(struct file *filp, struct kobject *kobj,
				   struct bin_attribute *attr, char *buf,
				   loff_t pos, size_t count)
{
	struct device *dev;
	struct nvmem_device *nvmem;
	int rc;

	if (attr->private)
		dev = attr->private;
	else
		dev = kobj_to_dev(kobj);
	nvmem = to_nvmem_device(dev);

	/* Stop the user from reading */
	if (pos >= nvmem->size)
		return 0;

	if (!IS_ALIGNED(pos, nvmem->stride))
		return -EINVAL;

	if (count < nvmem->word_size)
		return -EINVAL;

	if (pos + count > nvmem->size)
		count = nvmem->size - pos;

	count = round_down(count, nvmem->word_size);

	if (!nvmem->reg_read)
		return -EPERM;

	rc = nvmem_reg_read(nvmem, pos, buf, count);

	if (rc)
		return rc;

	return count;
}

static ssize_t bin_attr_nvmem_write(struct file *filp, struct kobject *kobj,
				    struct bin_attribute *attr, char *buf,
				    loff_t pos, size_t count)
{
	struct device *dev;
	struct nvmem_device *nvmem;
	int rc;

	if (attr->private)
		dev = attr->private;
	else
		dev = kobj_to_dev(kobj);
	nvmem = to_nvmem_device(dev);

	/* Stop the user from writing */
	if (pos >= nvmem->size)
		return -EFBIG;

	if (!IS_ALIGNED(pos, nvmem->stride))
		return -EINVAL;

	if (count < nvmem->word_size)
		return -EINVAL;

	if (pos + count > nvmem->size)
		count = nvmem->size - pos;

	count = round_down(count, nvmem->word_size);

	if (!nvmem->reg_write)
		return -EPERM;

	rc = nvmem_reg_write(nvmem, pos, buf, count);

	if (rc)
		return rc;

	return count;
}

static umode_t nvmem_bin_attr_get_umode(struct nvmem_device *nvmem)
{
	umode_t mode = 0400;

	if (!nvmem->root_only)
		mode |= 0044;

	if (!nvmem->read_only)
		mode |= 0200;

	if (!nvmem->reg_write)
		mode &= ~0200;

	if (!nvmem->reg_read)
		mode &= ~0444;

	return mode;
}

static umode_t nvmem_bin_attr_is_visible(struct kobject *kobj,
					 struct bin_attribute *attr, int i)
{
	struct device *dev = kobj_to_dev(kobj);
	struct nvmem_device *nvmem = to_nvmem_device(dev);

	attr->size = nvmem->size;

	return nvmem_bin_attr_get_umode(nvmem);
}

static struct nvmem_cell *nvmem_create_cell(struct nvmem_cell_entry *entry,
					    const char *id, int index);

static ssize_t nvmem_cell_attr_read(struct file *filp, struct kobject *kobj,
				    struct bin_attribute *attr, char *buf,
				    loff_t pos, size_t count)
{
	struct nvmem_cell_entry *entry;
	struct nvmem_cell *cell = NULL;
	size_t cell_sz, read_len;
	void *content;

	entry = attr->private;
	cell = nvmem_create_cell(entry, entry->name, 0);
	if (IS_ERR(cell))
		return PTR_ERR(cell);

	if (!cell)
		return -EINVAL;

	content = nvmem_cell_read(cell, &cell_sz);
	if (IS_ERR(content)) {
		read_len = PTR_ERR(content);
		goto destroy_cell;
	}

	read_len = min_t(unsigned int, cell_sz - pos, count);
	memcpy(buf, content + pos, read_len);
	kfree(content);

destroy_cell:
	kfree_const(cell->id);
	kfree(cell);

	return read_len;
}

/* default read/write permissions */
static struct bin_attribute bin_attr_rw_nvmem = {
	.attr	= {
		.name	= "nvmem",
		.mode	= 0644,
	},
	.read	= bin_attr_nvmem_read,
	.write	= bin_attr_nvmem_write,
};

static struct bin_attribute *nvmem_bin_attributes[] = {
	&bin_attr_rw_nvmem,
	NULL,
};

static const struct attribute_group nvmem_bin_group = {
	.bin_attrs	= nvmem_bin_attributes,
	.attrs		= nvmem_attrs,
	.is_bin_visible = nvmem_bin_attr_is_visible,
};

/* Cell attributes will be dynamically allocated */
static struct attribute_group nvmem_cells_group = {
	.name		= "cells",
};

static const struct attribute_group *nvmem_dev_groups[] = {
	&nvmem_bin_group,
	NULL,
};

static const struct attribute_group *nvmem_cells_groups[] = {
	&nvmem_cells_group,
	NULL,
};

static struct bin_attribute bin_attr_nvmem_eeprom_compat = {
	.attr	= {
		.name	= "eeprom",
	},
	.read	= bin_attr_nvmem_read,
	.write	= bin_attr_nvmem_write,
};

/*
 * nvmem_setup_compat() - Create an additional binary entry in
 * drivers sys directory, to be backwards compatible with the older
 * drivers/misc/eeprom drivers.
 */
static int nvmem_sysfs_setup_compat(struct nvmem_device *nvmem,
				    const struct nvmem_config *config)
{
	int rval;

	if (!config->compat)
		return 0;

	if (!config->base_dev)
		return -EINVAL;

	if (config->type == NVMEM_TYPE_FRAM)
		bin_attr_nvmem_eeprom_compat.attr.name = "fram";

	nvmem->eeprom = bin_attr_nvmem_eeprom_compat;
	nvmem->eeprom.attr.mode = nvmem_bin_attr_get_umode(nvmem);
	nvmem->eeprom.size = nvmem->size;
#ifdef CONFIG_DEBUG_LOCK_ALLOC
	nvmem->eeprom.attr.key = &eeprom_lock_key;
#endif
	nvmem->eeprom.private = &nvmem->dev;
	nvmem->base_dev = config->base_dev;

	rval = device_create_bin_file(nvmem->base_dev, &nvmem->eeprom);
	if (rval) {
		dev_err(&nvmem->dev,
			"Failed to create eeprom binary file %d\n", rval);
		return rval;
	}

	nvmem->flags |= FLAG_COMPAT;

	return 0;
}

static void nvmem_sysfs_remove_compat(struct nvmem_device *nvmem,
			      const struct nvmem_config *config)
{
	if (config->compat)
		device_remove_bin_file(nvmem->base_dev, &nvmem->eeprom);
}

static int nvmem_populate_sysfs_cells(struct nvmem_device *nvmem)
{
	struct bin_attribute **cells_attrs, *attrs;
	struct nvmem_cell_entry *entry;
	unsigned int ncells = 0, i = 0;
	int ret = 0;

	mutex_lock(&nvmem_mutex);

	if (list_empty(&nvmem->cells) || nvmem->sysfs_cells_populated) {
		nvmem_cells_group.bin_attrs = NULL;
		goto unlock_mutex;
	}

	/* Allocate an array of attributes with a sentinel */
	ncells = list_count_nodes(&nvmem->cells);
	cells_attrs = devm_kcalloc(&nvmem->dev, ncells + 1,
				   sizeof(struct bin_attribute *), GFP_KERNEL);
	if (!cells_attrs) {
		ret = -ENOMEM;
		goto unlock_mutex;
	}

	attrs = devm_kcalloc(&nvmem->dev, ncells, sizeof(struct bin_attribute), GFP_KERNEL);
	if (!attrs) {
		ret = -ENOMEM;
		goto unlock_mutex;
	}

	/* Initialize each attribute to take the name and size of the cell */
	list_for_each_entry(entry, &nvmem->cells, node) {
		sysfs_bin_attr_init(&attrs[i]);
		attrs[i].attr.name = devm_kasprintf(&nvmem->dev, GFP_KERNEL,
						    "%s@%x,%x", entry->name,
						    entry->offset,
						    entry->bit_offset);
		attrs[i].attr.mode = 0444;
		attrs[i].size = entry->bytes;
		attrs[i].read = &nvmem_cell_attr_read;
		attrs[i].private = entry;
		if (!attrs[i].attr.name) {
			ret = -ENOMEM;
			goto unlock_mutex;
		}

		cells_attrs[i] = &attrs[i];
		i++;
	}

	nvmem_cells_group.bin_attrs = cells_attrs;

	ret = devm_device_add_groups(&nvmem->dev, nvmem_cells_groups);
	if (ret)
		goto unlock_mutex;

	nvmem->sysfs_cells_populated = true;

unlock_mutex:
	mutex_unlock(&nvmem_mutex);

	return ret;
}

#else /* CONFIG_NVMEM_SYSFS */

static int nvmem_sysfs_setup_compat(struct nvmem_device *nvmem,
				    const struct nvmem_config *config)
{
	return -ENOSYS;
}
static void nvmem_sysfs_remove_compat(struct nvmem_device *nvmem,
				      const struct nvmem_config *config)
{
}

#endif /* CONFIG_NVMEM_SYSFS */

static void nvmem_release(struct device *dev)
{
	struct nvmem_device *nvmem = to_nvmem_device(dev);

	ida_free(&nvmem_ida, nvmem->id);
	gpiod_put(nvmem->wp_gpio);
	kfree(nvmem);
}

static const struct device_type nvmem_provider_type = {
	.release	= nvmem_release,
};

static struct bus_type nvmem_bus_type = {
	.name		= "nvmem",
};

static void nvmem_cell_entry_drop(struct nvmem_cell_entry *cell)
{
	blocking_notifier_call_chain(&nvmem_notifier, NVMEM_CELL_REMOVE, cell);
	mutex_lock(&nvmem_mutex);
	list_del(&cell->node);
	mutex_unlock(&nvmem_mutex);
	of_node_put(cell->np);
	kfree_const(cell->name);
	kfree(cell);
}

static void nvmem_device_remove_all_cells(const struct nvmem_device *nvmem)
{
	struct nvmem_cell_entry *cell, *p;

	list_for_each_entry_safe(cell, p, &nvmem->cells, node)
		nvmem_cell_entry_drop(cell);
}

static void nvmem_cell_entry_add(struct nvmem_cell_entry *cell)
{
	mutex_lock(&nvmem_mutex);
	list_add_tail(&cell->node, &cell->nvmem->cells);
	mutex_unlock(&nvmem_mutex);
	blocking_notifier_call_chain(&nvmem_notifier, NVMEM_CELL_ADD, cell);
}

static int nvmem_cell_info_to_nvmem_cell_entry_nodup(struct nvmem_device *nvmem,
						     const struct nvmem_cell_info *info,
						     struct nvmem_cell_entry *cell)
{
	cell->nvmem = nvmem;
	cell->offset = info->offset;
	cell->raw_len = info->raw_len ?: info->bytes;
	cell->bytes = info->bytes;
	cell->name = info->name;
	cell->read_post_process = info->read_post_process;
	cell->priv = info->priv;

	cell->bit_offset = info->bit_offset;
	cell->nbits = info->nbits;
	cell->np = info->np;

	if (cell->nbits)
		cell->bytes = DIV_ROUND_UP(cell->nbits + cell->bit_offset,
					   BITS_PER_BYTE);

	if (!IS_ALIGNED(cell->offset, nvmem->stride)) {
		dev_err(&nvmem->dev,
			"cell %s unaligned to nvmem stride %d\n",
			cell->name ?: "<unknown>", nvmem->stride);
		return -EINVAL;
	}

	return 0;
}

static int nvmem_cell_info_to_nvmem_cell_entry(struct nvmem_device *nvmem,
					       const struct nvmem_cell_info *info,
					       struct nvmem_cell_entry *cell)
{
	int err;

	err = nvmem_cell_info_to_nvmem_cell_entry_nodup(nvmem, info, cell);
	if (err)
		return err;

	cell->name = kstrdup_const(info->name, GFP_KERNEL);
	if (!cell->name)
		return -ENOMEM;

	return 0;
}

/**
 * nvmem_add_one_cell() - Add one cell information to an nvmem device
 *
 * @nvmem: nvmem device to add cells to.
 * @info: nvmem cell info to add to the device
 *
 * Return: 0 or negative error code on failure.
 */
int nvmem_add_one_cell(struct nvmem_device *nvmem,
		       const struct nvmem_cell_info *info)
{
	struct nvmem_cell_entry *cell;
	int rval;

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

	rval = nvmem_cell_info_to_nvmem_cell_entry(nvmem, info, cell);
	if (rval) {
		kfree(cell);
		return rval;
	}

	nvmem_cell_entry_add(cell);

	return 0;
}
EXPORT_SYMBOL_GPL(nvmem_add_one_cell);

/**
 * nvmem_add_cells() - Add cell information to an nvmem device
 *
 * @nvmem: nvmem device to add cells to.
 * @info: nvmem cell info to add to the device
 * @ncells: number of cells in info
 *
 * Return: 0 or negative error code on failure.
 */
static int nvmem_add_cells(struct nvmem_device *nvmem,
		    const struct nvmem_cell_info *info,
		    int ncells)
{
	int i, rval;

	for (i = 0; i < ncells; i++) {
		rval = nvmem_add_one_cell(nvmem, &info[i]);
		if (rval)
			return rval;
	}

	return 0;
}

/**
 * nvmem_register_notifier() - Register a notifier block for nvmem events.
 *
 * @nb: notifier block to be called on nvmem events.
 *
 * Return: 0 on success, negative error number on failure.
 */
int nvmem_register_notifier(struct notifier_block *nb)
{
	return blocking_notifier_chain_register(&nvmem_notifier, nb);
}
EXPORT_SYMBOL_GPL(nvmem_register_notifier);

/**
 * nvmem_unregister_notifier() - Unregister a notifier block for nvmem events.
 *
 * @nb: notifier block to be unregistered.
 *
 * Return: 0 on success, negative error number on failure.
 */
int nvmem_unregister_notifier(struct notifier_block *nb)
{
	return blocking_notifier_chain_unregister(&nvmem_notifier, nb);
}
EXPORT_SYMBOL_GPL(nvmem_unregister_notifier);

static int nvmem_add_cells_from_table(struct nvmem_device *nvmem)
{
	const struct nvmem_cell_info *info;
	struct nvmem_cell_table *table;
	struct nvmem_cell_entry *cell;
	int rval = 0, i;

	mutex_lock(&nvmem_cell_mutex);
	list_for_each_entry(table, &nvmem_cell_tables, node) {
		if (strcmp(nvmem_dev_name(nvmem), table->nvmem_name) == 0) {
			for (i = 0; i < table->ncells; i++) {
				info = &table->cells[i];

				cell = kzalloc(sizeof(*cell), GFP_KERNEL);
				if (!cell) {
					rval = -ENOMEM;
					goto out;
				}

				rval = nvmem_cell_info_to_nvmem_cell_entry(nvmem, info, cell);
				if (rval) {
					kfree(cell);
					goto out;
				}

				nvmem_cell_entry_add(cell);
			}
		}
	}

out:
	mutex_unlock(&nvmem_cell_mutex);
	return rval;
}

static struct nvmem_cell_entry *
nvmem_find_cell_entry_by_name(struct nvmem_device *nvmem, const char *cell_id)
{
	struct nvmem_cell_entry *iter, *cell = NULL;

	mutex_lock(&nvmem_mutex);
	list_for_each_entry(iter, &nvmem->cells, node) {
		if (strcmp(cell_id, iter->name) == 0) {
			cell = iter;
			break;
		}
	}
	mutex_unlock(&nvmem_mutex);

	return cell;
}

static int nvmem_validate_keepouts(struct nvmem_device *nvmem)
{
	unsigned int cur = 0;
	const struct nvmem_keepout *keepout = nvmem->keepout;
	const struct nvmem_keepout *keepoutend = keepout + nvmem->nkeepout;

	while (keepout < keepoutend) {
		/* Ensure keepouts are sorted and don't overlap. */
		if (keepout->start < cur) {
			dev_err(&nvmem->dev,
				"Keepout regions aren't sorted or overlap.\n");

			return -ERANGE;
		}

		if (keepout->end < keepout->start) {
			dev_err(&nvmem->dev,
				"Invalid keepout region.\n");

			return -EINVAL;
		}

		/*
		 * Validate keepouts (and holes between) don't violate
		 * word_size constraints.
		 */
		if ((keepout->end - keepout->start < nvmem->word_size) ||
		    ((keepout->start != cur) &&
		     (keepout->start - cur < nvmem->word_size))) {

			dev_err(&nvmem->dev,
				"Keepout regions violate word_size constraints.\n");

			return -ERANGE;
		}

		/* Validate keepouts don't violate stride (alignment). */
		if (!IS_ALIGNED(keepout->start, nvmem->stride) ||
		    !IS_ALIGNED(keepout->end, nvmem->stride)) {

			dev_err(&nvmem->dev,
				"Keepout regions violate stride.\n");

			return -EINVAL;
		}

		cur = keepout->end;
		keepout++;
	}

	return 0;
}

static int nvmem_add_cells_from_dt(struct nvmem_device *nvmem, struct device_node *np)
{
	struct device *dev = &nvmem->dev;
	struct device_node *child;
	const __be32 *addr;
	int len, ret;

	for_each_child_of_node(np, child) {
		struct nvmem_cell_info info = {0};

		addr = of_get_property(child, "reg", &len);
		if (!addr)
			continue;
		if (len < 2 * sizeof(u32)) {
			dev_err(dev, "nvmem: invalid reg on %pOF\n", child);
			of_node_put(child);
			return -EINVAL;
		}

		info.offset = be32_to_cpup(addr++);
		info.bytes = be32_to_cpup(addr);
		info.name = kasprintf(GFP_KERNEL, "%pOFn", child);

		addr = of_get_property(child, "bits", &len);
		if (addr && len == (2 * sizeof(u32))) {
			info.bit_offset = be32_to_cpup(addr++);
			info.nbits = be32_to_cpup(addr);
			if (info.bit_offset >= BITS_PER_BYTE || info.nbits < 1) {
				dev_err(dev, "nvmem: invalid bits on %pOF\n", child);
				of_node_put(child);
				return -EINVAL;
			}
		}

		info.np = of_node_get(child);

		if (nvmem->fixup_dt_cell_info)
			nvmem->fixup_dt_cell_info(nvmem, &info);

		ret = nvmem_add_one_cell(nvmem, &info);
		kfree(info.name);
		if (ret) {
			of_node_put(child);
			return ret;
		}
	}

	return 0;
}

static int nvmem_add_cells_from_legacy_of(struct nvmem_device *nvmem)
{
	return nvmem_add_cells_from_dt(nvmem, nvmem->dev.of_node);
}

static int nvmem_add_cells_from_fixed_layout(struct nvmem_device *nvmem)
{
	struct device_node *layout_np;
	int err = 0;

	layout_np = of_nvmem_layout_get_container(nvmem);
	if (!layout_np)
		return 0;

	if (of_device_is_compatible(layout_np, "fixed-layout"))
		err = nvmem_add_cells_from_dt(nvmem, layout_np);

	of_node_put(layout_np);

	return err;
}

int nvmem_layout_register(struct nvmem_layout *layout)
{
	int ret;

	if (!layout->add_cells)
		return -EINVAL;

	/* Populate the cells */
	ret = layout->add_cells(layout);
	if (ret)
		return ret;

#ifdef CONFIG_NVMEM_SYSFS
	ret = nvmem_populate_sysfs_cells(layout->nvmem);
	if (ret) {
		nvmem_device_remove_all_cells(layout->nvmem);
		return ret;
	}
#endif

	return 0;
}
EXPORT_SYMBOL_GPL(nvmem_layout_register);

void nvmem_layout_unregister(struct nvmem_layout *layout)
{
	/* Keep the API even with an empty stub in case we need it later */
}
EXPORT_SYMBOL_GPL(nvmem_layout_unregister);

/**
 * nvmem_register() - Register a nvmem device for given nvmem_config.
 * Also creates a binary entry in /sys/bus/nvmem/devices/dev-name/nvmem
 *
 * @config: nvmem device configuration with which nvmem device is created.
 *
 * Return: Will be an ERR_PTR() on error or a valid pointer to nvmem_device
 * on success.
 */

struct nvmem_device *nvmem_register(const struct nvmem_config *config)
{
	struct nvmem_device *nvmem;
	int rval;

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

	if (!config->reg_read && !config->reg_write)
		return ERR_PTR(-EINVAL);

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

	rval = ida_alloc(&nvmem_ida, GFP_KERNEL);
	if (rval < 0) {
		kfree(nvmem);
		return ERR_PTR(rval);
	}

	nvmem->id = rval;

	nvmem->dev.type = &nvmem_provider_type;
	nvmem->dev.bus = &nvmem_bus_type;
	nvmem->dev.parent = config->dev;

	device_initialize(&nvmem->dev);

	if (!config->ignore_wp)
		nvmem->wp_gpio = gpiod_get_optional(config->dev, "wp",
						    GPIOD_OUT_HIGH);
	if (IS_ERR(nvmem->wp_gpio)) {
		rval = PTR_ERR(nvmem->wp_gpio);
		nvmem->wp_gpio = NULL;
		goto err_put_device;
	}

	kref_init(&nvmem->refcnt);
	INIT_LIST_HEAD(&nvmem->cells);
	nvmem->fixup_dt_cell_info = config->fixup_dt_cell_info;

	nvmem->owner = config->owner;
	if (!nvmem->owner && config->dev->driver)
		nvmem->owner = config->dev->driver->owner;
	nvmem->stride = config->stride ?: 1;
	nvmem->word_size = config->word_size ?: 1;
	nvmem->size = config->size;
	nvmem->root_only = config->root_only;
	nvmem->priv = config->priv;
	nvmem->type = config->type;
	nvmem->reg_read = config->reg_read;
	nvmem->reg_write = config->reg_write;
	nvmem->keepout = config->keepout;
	nvmem->nkeepout = config->nkeepout;
	if (config->of_node)
		nvmem->dev.of_node = config->of_node;
	else
		nvmem->dev.of_node = config->dev->of_node;

	switch (config->id) {
	case NVMEM_DEVID_NONE:
		rval = dev_set_name(&nvmem->dev, "%s", config->name);
		break;
	case NVMEM_DEVID_AUTO:
		rval = dev_set_name(&nvmem->dev, "%s%d", config->name, nvmem->id);
		break;
	default:
		rval = dev_set_name(&nvmem->dev, "%s%d",
			     config->name ? : "nvmem",
			     config->name ? config->id : nvmem->id);
		break;
	}

	if (rval)
		goto err_put_device;

	nvmem->read_only = device_property_present(config->dev, "read-only") ||
			   config->read_only || !nvmem->reg_write;

#ifdef CONFIG_NVMEM_SYSFS
	nvmem->dev.groups = nvmem_dev_groups;
#endif

	if (nvmem->nkeepout) {
		rval = nvmem_validate_keepouts(nvmem);
		if (rval)
			goto err_put_device;
	}

	if (config->compat) {
		rval = nvmem_sysfs_setup_compat(nvmem, config);
		if (rval)
			goto err_put_device;
	}

	if (config->cells) {
		rval = nvmem_add_cells(nvmem, config->cells, config->ncells);
		if (rval)
			goto err_remove_cells;
	}

	rval = nvmem_add_cells_from_table(nvmem);
	if (rval)
		goto err_remove_cells;

	if (config->add_legacy_fixed_of_cells) {
		rval = nvmem_add_cells_from_legacy_of(nvmem);
		if (rval)
			goto err_remove_cells;
	}

	rval = nvmem_add_cells_from_fixed_layout(nvmem);
	if (rval)
		goto err_remove_cells;

	dev_dbg(&nvmem->dev, "Registering nvmem device %s\n", config->name);

	rval = device_add(&nvmem->dev);
	if (rval)
		goto err_remove_cells;

	rval = nvmem_populate_layout(nvmem);
	if (rval)
		goto err_remove_dev;

#ifdef CONFIG_NVMEM_SYSFS
	rval = nvmem_populate_sysfs_cells(nvmem);
	if (rval)
		goto err_destroy_layout;
#endif

	blocking_notifier_call_chain(&nvmem_notifier, NVMEM_ADD, nvmem);

	return nvmem;

#ifdef CONFIG_NVMEM_SYSFS
err_destroy_layout:
	nvmem_destroy_layout(nvmem);
#endif
err_remove_dev:
	device_del(&nvmem->dev);
err_remove_cells:
	nvmem_device_remove_all_cells(nvmem);
	if (config->compat)
		nvmem_sysfs_remove_compat(nvmem, config);
err_put_device:
	put_device(&nvmem->dev);

	return ERR_PTR(rval);
}
EXPORT_SYMBOL_GPL(nvmem_register);

static void nvmem_device_release(struct kref *kref)
{
	struct nvmem_device *nvmem;

	nvmem = container_of(kref, struct nvmem_device, refcnt);

	blocking_notifier_call_chain(&nvmem_notifier, NVMEM_REMOVE, nvmem);

	if (nvmem->flags & FLAG_COMPAT)
		device_remove_bin_file(nvmem->base_dev, &nvmem->eeprom);

	nvmem_device_remove_all_cells(nvmem);
	nvmem_destroy_layout(nvmem);
	device_unregister(&nvmem->dev);
}

/**
 * nvmem_unregister() - Unregister previously registered nvmem device
 *
 * @nvmem: Pointer to previously registered nvmem device.
 */
void nvmem_unregister(struct nvmem_device *nvmem)
{
	if (nvmem)
		kref_put(&nvmem->refcnt, nvmem_device_release);
}
EXPORT_SYMBOL_GPL(nvmem_unregister);

static void devm_nvmem_unregister(void *nvmem)
{
	nvmem_unregister(nvmem);
}

/**
 * devm_nvmem_register() - Register a managed nvmem device for given
 * nvmem_config.
 * Also creates a binary entry in /sys/bus/nvmem/devices/dev-name/nvmem
 *
 * @dev: Device that uses the nvmem device.
 * @config: nvmem device configuration with which nvmem device is created.
 *
 * Return: Will be an ERR_PTR() on error or a valid pointer to nvmem_device
 * on success.
 */
struct nvmem_device *devm_nvmem_register(struct device *dev,
					 const struct nvmem_config *config)
{
	struct nvmem_device *nvmem;
	int ret;

	nvmem = nvmem_register(config);
	if (IS_ERR(nvmem))
		return nvmem;

	ret = devm_add_action_or_reset(dev, devm_nvmem_unregister, nvmem);
	if (ret)
		return ERR_PTR(ret);

	return nvmem;
}
EXPORT_SYMBOL_GPL(devm_nvmem_register);

static struct nvmem_device *__nvmem_device_get(void *data,
			int (*match)(struct device *dev, const void *data))
{
	struct nvmem_device *nvmem = NULL;
	struct device *dev;

	mutex_lock(&nvmem_mutex);
	dev = bus_find_device(&nvmem_bus_type, NULL, data, match);
	if (dev)
		nvmem = to_nvmem_device(dev);
	mutex_unlock(&nvmem_mutex);
	if (!nvmem)
		return ERR_PTR(-EPROBE_DEFER);

	if (!try_module_get(nvmem->owner)) {
		dev_err(&nvmem->dev,
			"could not increase module refcount for cell %s\n",
			nvmem_dev_name(nvmem));

		put_device(&nvmem->dev);
		return ERR_PTR(-EINVAL);
	}

	kref_get(&nvmem->refcnt);

	return nvmem;
}

static void __nvmem_device_put(struct nvmem_device *nvmem)
{
	put_device(&nvmem->dev);
	module_put(nvmem->owner);
	kref_put(&nvmem->refcnt, nvmem_device_release);
}

#if IS_ENABLED(CONFIG_OF)
/**
 * of_nvmem_device_get() - Get nvmem device from a given id
 *
 * @np: Device tree node that uses the nvmem device.
 * @id: nvmem name from nvmem-names property.
 *
 * Return: ERR_PTR() on error or a valid pointer to a struct nvmem_device
 * on success.
 */
struct nvmem_device *of_nvmem_device_get(struct device_node *np, const char *id)
{

	struct device_node *nvmem_np;
	struct nvmem_device *nvmem;
	int index = 0;

	if (id)
		index = of_property_match_string(np, "nvmem-names", id);

	nvmem_np = of_parse_phandle(np, "nvmem", index);
	if (!nvmem_np)
		return ERR_PTR(-ENOENT);

	nvmem = __nvmem_device_get(nvmem_np, device_match_of_node);
	of_node_put(nvmem_np);
	return nvmem;
}
EXPORT_SYMBOL_GPL(of_nvmem_device_get);
#endif

/**
 * nvmem_device_get() - Get nvmem device from a given id
 *
 * @dev: Device that uses the nvmem device.
 * @dev_name: name of the requested nvmem device.
 *
 * Return: ERR_PTR() on error or a valid pointer to a struct nvmem_device
 * on success.
 */
struct nvmem_device *nvmem_device_get(struct device *dev, const char *dev_name)
{
	if (dev->of_node) { /* try dt first */
		struct nvmem_device *nvmem;

		nvmem = of_nvmem_device_get(dev->of_node, dev_name);

		if (!IS_ERR(nvmem) || PTR_ERR(nvmem) == -EPROBE_DEFER)
			return nvmem;

	}

	return __nvmem_device_get((void *)dev_name, device_match_name);
}
EXPORT_SYMBOL_GPL(nvmem_device_get);

/**
 * nvmem_device_find() - Find nvmem device with matching function
 *
 * @data: Data to pass to match function
 * @match: Callback function to check device
 *
 * Return: ERR_PTR() on error or a valid pointer to a struct nvmem_device
 * on success.
 */
struct nvmem_device *nvmem_device_find(void *data,
			int (*match)(struct device *dev, const void *data))
{
	return __nvmem_device_get(data, match);
}
EXPORT_SYMBOL_GPL(nvmem_device_find);

static int devm_nvmem_device_match(struct device *dev, void *res, void *data)
{
	struct nvmem_device **nvmem = res;

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

	return *nvmem == data;
}

static void devm_nvmem_device_release(struct device *dev, void *res)
{
	nvmem_device_put(*(struct nvmem_device **)res);
}

/**
 * devm_nvmem_device_put() - put alredy got nvmem device
 *
 * @dev: Device that uses the nvmem device.
 * @nvmem: pointer to nvmem device allocated by devm_nvmem_cell_get(),
 * that needs to be released.
 */
void devm_nvmem_device_put(struct device *dev, struct nvmem_device *nvmem)
{
	int ret;

	ret = devres_release(dev, devm_nvmem_device_release,
			     devm_nvmem_device_match, nvmem);

	WARN_ON(ret);
}
EXPORT_SYMBOL_GPL(devm_nvmem_device_put);

/**
 * nvmem_device_put() - put alredy got nvmem device
 *
 * @nvmem: pointer to nvmem device that needs to be released.
 */
void nvmem_device_put(struct nvmem_device *nvmem)
{
	__nvmem_device_put(nvmem);
}
EXPORT_SYMBOL_GPL(nvmem_device_put);

/**
 * devm_nvmem_device_get() - Get nvmem cell of device form a given id
 *
 * @dev: Device that requests the nvmem device.
 * @id: name id for the requested nvmem device.
 *
 * Return: ERR_PTR() on error or a valid pointer to a struct nvmem_cell
 * on success.  The nvmem_cell will be freed by the automatically once the
 * device is freed.
 */
struct nvmem_device *devm_nvmem_device_get(struct device *dev, const char *id)
{
	struct nvmem_device **ptr, *nvmem;

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

	nvmem = nvmem_device_get(dev, id);
	if (!IS_ERR(nvmem)) {
		*ptr = nvmem;
		devres_add(dev, ptr);
	} else {
		devres_free(ptr);
	}

	return nvmem;
}
EXPORT_SYMBOL_GPL(devm_nvmem_device_get);

static struct nvmem_cell *nvmem_create_cell(struct nvmem_cell_entry *entry,
					    const char *id, int index)
{
	struct nvmem_cell *cell;
	const char *name = NULL;

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

	if (id) {
		name = kstrdup_const(id, GFP_KERNEL);
		if (!name) {
			kfree(cell);
			return ERR_PTR(-ENOMEM);
		}
	}

	cell->id = name;
	cell->entry = entry;
	cell->index = index;

	return cell;
}

static struct nvmem_cell *
nvmem_cell_get_from_lookup(struct device *dev, const char *con_id)
{
	struct nvmem_cell_entry *cell_entry;
	struct nvmem_cell *cell = ERR_PTR(-ENOENT);
	struct nvmem_cell_lookup *lookup;
	struct nvmem_device *nvmem;
	const char *dev_id;

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

	dev_id = dev_name(dev);

	mutex_lock(&nvmem_lookup_mutex);

	list_for_each_entry(lookup, &nvmem_lookup_list, node) {
		if ((strcmp(lookup->dev_id, dev_id) == 0) &&
		    (strcmp(lookup->con_id, con_id) == 0)) {
			/* This is the right entry. */
			nvmem = __nvmem_device_get((void *)lookup->nvmem_name,
						   device_match_name);
			if (IS_ERR(nvmem)) {
				/* Provider may not be registered yet. */
				cell = ERR_CAST(nvmem);
				break;
			}

			cell_entry = nvmem_find_cell_entry_by_name(nvmem,
								   lookup->cell_name);
			if (!cell_entry) {
				__nvmem_device_put(nvmem);
				cell = ERR_PTR(-ENOENT);
			} else {
				cell = nvmem_create_cell(cell_entry, con_id, 0);
				if (IS_ERR(cell))
					__nvmem_device_put(nvmem);
			}
			break;
		}
	}

	mutex_unlock(&nvmem_lookup_mutex);
	return cell;
}

static void nvmem_layout_module_put(struct nvmem_device *nvmem)
{
	if (nvmem->layout && nvmem->layout->dev.driver)
		module_put(nvmem->layout->dev.driver->owner);
}

#if IS_ENABLED(CONFIG_OF)
static struct nvmem_cell_entry *
nvmem_find_cell_entry_by_node(struct nvmem_device *nvmem, struct device_node *np)
{
	struct nvmem_cell_entry *iter, *cell = NULL;

	mutex_lock(&nvmem_mutex);
	list_for_each_entry(iter, &nvmem->cells, node) {
		if (np == iter->np) {
			cell = iter;
			break;
		}
	}
	mutex_unlock(&nvmem_mutex);

	return cell;
}

static int nvmem_layout_module_get_optional(struct nvmem_device *nvmem)
{
	if (!nvmem->layout)
		return 0;

	if (!nvmem->layout->dev.driver ||
	    !try_module_get(nvmem->layout->dev.driver->owner))
		return -EPROBE_DEFER;

	return 0;
}

/**
 * of_nvmem_cell_get() - Get a nvmem cell from given device node and cell id
 *
 * @np: Device tree node that uses the nvmem cell.
 * @id: nvmem cell name from nvmem-cell-names property, or NULL
 *      for the cell at index 0 (the lone cell with no accompanying
 *      nvmem-cell-names property).
 *
 * Return: Will be an ERR_PTR() on error or a valid pointer
 * to a struct nvmem_cell.  The nvmem_cell will be freed by the
 * nvmem_cell_put().
 */
struct nvmem_cell *of_nvmem_cell_get(struct device_node *np, const char *id)
{
	struct device_node *cell_np, *nvmem_np;
	struct nvmem_device *nvmem;
	struct nvmem_cell_entry *cell_entry;
	struct nvmem_cell *cell;
	struct of_phandle_args cell_spec;
	int index = 0;
	int cell_index = 0;
	int ret;

	/* if cell name exists, find index to the name */
	if (id)
		index = of_property_match_string(np, "nvmem-cell-names", id);

	ret = of_parse_phandle_with_optional_args(np, "nvmem-cells",
						  "#nvmem-cell-cells",
						  index, &cell_spec);
	if (ret)
		return ERR_PTR(-ENOENT);

	if (cell_spec.args_count > 1)
		return ERR_PTR(-EINVAL);

	cell_np = cell_spec.np;
	if (cell_spec.args_count)
		cell_index = cell_spec.args[0];

	nvmem_np = of_get_parent(cell_np);
	if (!nvmem_np) {
		of_node_put(cell_np);
		return ERR_PTR(-EINVAL);
	}

	/* nvmem layouts produce cells within the nvmem-layout container */
	if (of_node_name_eq(nvmem_np, "nvmem-layout")) {
		nvmem_np = of_get_next_parent(nvmem_np);
		if (!nvmem_np) {
			of_node_put(cell_np);
			return ERR_PTR(-EINVAL);
		}
	}

	nvmem = __nvmem_device_get(nvmem_np, device_match_of_node);
	of_node_put(nvmem_np);
	if (IS_ERR(nvmem)) {
		of_node_put(cell_np);
		return ERR_CAST(nvmem);
	}

	ret = nvmem_layout_module_get_optional(nvmem);
	if (ret) {
		of_node_put(cell_np);
		__nvmem_device_put(nvmem);
		return ERR_PTR(ret);
	}

	cell_entry = nvmem_find_cell_entry_by_node(nvmem, cell_np);
	of_node_put(cell_np);
	if (!cell_entry) {
		__nvmem_device_put(nvmem);
		nvmem_layout_module_put(nvmem);
		if (nvmem->layout)
			return ERR_PTR(-EPROBE_DEFER);
		else
			return ERR_PTR(-ENOENT);
	}

	cell = nvmem_create_cell(cell_entry, id, cell_index);
	if (IS_ERR(cell)) {
		__nvmem_device_put(nvmem);
		nvmem_layout_module_put(nvmem);
	}

	return cell;
}
EXPORT_SYMBOL_GPL(of_nvmem_cell_get);
#endif

/**
 * nvmem_cell_get() - Get nvmem cell of device form a given cell name
 *
 * @dev: Device that requests the nvmem cell.
 * @id: nvmem cell name to get (this corresponds with the name from the
 *      nvmem-cell-names property for DT systems and with the con_id from
 *      the lookup entry for non-DT systems).
 *
 * Return: Will be an ERR_PTR() on error or a valid pointer
 * to a struct nvmem_cell.  The nvmem_cell will be freed by the
 * nvmem_cell_put().
 */
struct nvmem_cell *nvmem_cell_get(struct device *dev, const char *id)
{
	struct nvmem_cell *cell;

	if (dev->of_node) { /* try dt first */
		cell = of_nvmem_cell_get(dev->of_node, id);
		if (!IS_ERR(cell) || PTR_ERR(cell) == -EPROBE_DEFER)
			return cell;
	}

	/* NULL cell id only allowed for device tree; invalid otherwise */
	if (!id)
		return ERR_PTR(-EINVAL);

	return nvmem_cell_get_from_lookup(dev, id);
}
EXPORT_SYMBOL_GPL(nvmem_cell_get);

static void devm_nvmem_cell_release(struct device *dev, void *res)
{
	nvmem_cell_put(*(struct nvmem_cell **)res);
}

/**
 * devm_nvmem_cell_get() - Get nvmem cell of device form a given id
 *
 * @dev: Device that requests the nvmem cell.
 * @id: nvmem cell name id to get.
 *
 * Return: Will be an ERR_PTR() on error or a valid pointer
 * to a struct nvmem_cell.  The nvmem_cell will be freed by the
 * automatically once the device is freed.
 */
struct nvmem_cell *devm_nvmem_cell_get(struct device *dev, const char *id)
{
	struct nvmem_cell **ptr, *cell;

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

	cell = nvmem_cell_get(dev, id);
	if (!IS_ERR(cell)) {
		*ptr = cell;
		devres_add(dev, ptr);
	} else {
		devres_free(ptr);
	}

	return cell;
}
EXPORT_SYMBOL_GPL(devm_nvmem_cell_get);

static int devm_nvmem_cell_match(struct device *dev, void *res, void *data)
{
	struct nvmem_cell **c = res;

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

	return *c == data;
}

/**
 * devm_nvmem_cell_put() - Release previously allocated nvmem cell
 * from devm_nvmem_cell_get.
 *
 * @dev: Device that requests the nvmem cell.
 * @cell: Previously allocated nvmem cell by devm_nvmem_cell_get().
 */
void devm_nvmem_cell_put(struct device *dev, struct nvmem_cell *cell)
{
	int ret;

	ret = devres_release(dev, devm_nvmem_cell_release,
				devm_nvmem_cell_match, cell);

	WARN_ON(ret);
}
EXPORT_SYMBOL(devm_nvmem_cell_put);

/**
 * nvmem_cell_put() - Release previously allocated nvmem cell.
 *
 * @cell: Previously allocated nvmem cell by nvmem_cell_get().
 */
void nvmem_cell_put(struct nvmem_cell *cell)
{
	struct nvmem_device *nvmem = cell->entry->nvmem;

	if (cell->id)
		kfree_const(cell->id);

	kfree(cell);
	__nvmem_device_put(nvmem);
	nvmem_layout_module_put(nvmem);
}
EXPORT_SYMBOL_GPL(nvmem_cell_put);

static void nvmem_shift_read_buffer_in_place(struct nvmem_cell_entry *cell, void *buf)
{
	u8 *p, *b;
	int i, extra, bit_offset = cell->bit_offset;

	p = b = buf;
	if (bit_offset) {
		/* First shift */
		*b++ >>= bit_offset;

		/* setup rest of the bytes if any */
		for (i = 1; i < cell->bytes; i++) {
			/* Get bits from next byte and shift them towards msb */
			*p |= *b << (BITS_PER_BYTE - bit_offset);

			p = b;
			*b++ >>= bit_offset;
		}
	} else {
		/* point to the msb */
		p += cell->bytes - 1;
	}

	/* result fits in less bytes */
	extra = cell->bytes - DIV_ROUND_UP(cell->nbits, BITS_PER_BYTE);
	while (--extra >= 0)
		*p-- = 0;

	/* clear msb bits if any leftover in the last byte */
	if (cell->nbits % BITS_PER_BYTE)
		*p &= GENMASK((cell->nbits % BITS_PER_BYTE) - 1, 0);
}

static int __nvmem_cell_read(struct nvmem_device *nvmem,
			     struct nvmem_cell_entry *cell,
			     void *buf, size_t *len, const char *id, int index)
{
	int rc;

	rc = nvmem_reg_read(nvmem, cell->offset, buf, cell->raw_len);

	if (rc)
		return rc;

	/* shift bits in-place */
	if (cell->bit_offset || cell->nbits)
		nvmem_shift_read_buffer_in_place(cell, buf);

	if (cell->read_post_process) {
		rc = cell->read_post_process(cell->priv, id, index,
					     cell->offset, buf, cell->raw_len);
		if (rc)
			return rc;
	}

	if (len)
		*len = cell->bytes;

	return 0;
}

/**
 * nvmem_cell_read() - Read a given nvmem cell
 *
 * @cell: nvmem cell to be read.
 * @len: pointer to length of cell which will be populated on successful read;
 *	 can be NULL.
 *
 * Return: ERR_PTR() on error or a valid pointer to a buffer on success. The
 * buffer should be freed by the consumer with a kfree().
 */
void *nvmem_cell_read(struct nvmem_cell *cell, size_t *len)
{
	struct nvmem_cell_entry *entry = cell->entry;
	struct nvmem_device *nvmem = entry->nvmem;
	u8 *buf;
	int rc;

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

	buf = kzalloc(max_t(size_t, entry->raw_len, entry->bytes), GFP_KERNEL);
	if (!buf)
		return ERR_PTR(-ENOMEM);

	rc = __nvmem_cell_read(nvmem, cell->entry, buf, len, cell->id, cell->index);
	if (rc) {
		kfree(buf);
		return ERR_PTR(rc);
	}

	return buf;
}
EXPORT_SYMBOL_GPL(nvmem_cell_read);

static void *nvmem_cell_prepare_write_buffer(struct nvmem_cell_entry *cell,
					     u8 *_buf, int len)
{
	struct nvmem_device *nvmem = cell->nvmem;
	int i, rc, nbits, bit_offset = cell->bit_offset;
	u8 v, *p, *buf, *b, pbyte, pbits;

	nbits = cell->nbits;
	buf = kzalloc(cell->bytes, GFP_KERNEL);
	if (!buf)
		return ERR_PTR(-ENOMEM);

	memcpy(buf, _buf, len);
	p = b = buf;

	if (bit_offset) {
		pbyte = *b;
		*b <<= bit_offset;

		/* setup the first byte with lsb bits from nvmem */
		rc = nvmem_reg_read(nvmem, cell->offset, &v, 1);
		if (rc)
			goto err;
		*b++ |= GENMASK(bit_offset - 1, 0) & v;

		/* setup rest of the byte if any */
		for (i = 1; i < cell->bytes; i++) {
			/* Get last byte bits and shift them towards lsb */
			pbits = pbyte >> (BITS_PER_BYTE - 1 - bit_offset);
			pbyte = *b;
			p = b;
			*b <<= bit_offset;
			*b++ |= pbits;
		}
	}

	/* if it's not end on byte boundary */
	if ((nbits + bit_offset) % BITS_PER_BYTE) {
		/* setup the last byte with msb bits from nvmem */
		rc = nvmem_reg_read(nvmem,
				    cell->offset + cell->bytes - 1, &v, 1);
		if (rc)
			goto err;
		*p |= GENMASK(7, (nbits + bit_offset) % BITS_PER_BYTE) & v;

	}

	return buf;
err:
	kfree(buf);
	return ERR_PTR(rc);
}

static int __nvmem_cell_entry_write(struct nvmem_cell_entry *cell, void *buf, size_t len)
{
	struct nvmem_device *nvmem = cell->nvmem;
	int rc;

	if (!nvmem || nvmem->read_only ||
	    (cell->bit_offset == 0 && len != cell->bytes))
		return -EINVAL;

	/*
	 * Any cells which have a read_post_process hook are read-only because
	 * we cannot reverse the operation and it might affect other cells,
	 * too.
	 */
	if (cell->read_post_process)
		return -EINVAL;

	if (cell->bit_offset || cell->nbits) {
		buf = nvmem_cell_prepare_write_buffer(cell, buf, len);
		if (IS_ERR(buf))
			return PTR_ERR(buf);
	}

	rc = nvmem_reg_write(nvmem, cell->offset, buf, cell->bytes);

	/* free the tmp buffer */
	if (cell->bit_offset || cell->nbits)
		kfree(buf);

	if (rc)
		return rc;

	return len;
}

/**
 * nvmem_cell_write() - Write to a given nvmem cell
 *
 * @cell: nvmem cell to be written.
 * @buf: Buffer to be written.
 * @len: length of buffer to be written to nvmem cell.
 *
 * Return: length of bytes written or negative on failure.
 */
int nvmem_cell_write(struct nvmem_cell *cell, void *buf, size_t len)
{
	return __nvmem_cell_entry_write(cell->entry, buf, len);
}

EXPORT_SYMBOL_GPL(nvmem_cell_write);

static int nvmem_cell_read_common(struct device *dev, const char *cell_id,
				  void *val, size_t count)
{
	struct nvmem_cell *cell;
	void *buf;
	size_t len;

	cell = nvmem_cell_get(dev, cell_id);
	if (IS_ERR(cell))
		return PTR_ERR(cell);

	buf = nvmem_cell_read(cell, &len);
	if (IS_ERR(buf)) {
		nvmem_cell_put(cell);
		return PTR_ERR(buf);
	}
	if (len != count) {
		kfree(buf);
		nvmem_cell_put(cell);
		return -EINVAL;
	}
	memcpy(val, buf, count);
	kfree(buf);
	nvmem_cell_put(cell);

	return 0;
}

/**
 * nvmem_cell_read_u8() - Read a cell value as a u8
 *
 * @dev: Device that requests the nvmem cell.
 * @cell_id: Name of nvmem cell to read.
 * @val: pointer to output value.
 *
 * Return: 0 on success or negative errno.
 */
int nvmem_cell_read_u8(struct device *dev, const char *cell_id, u8 *val)
{
	return nvmem_cell_read_common(dev, cell_id, val, sizeof(*val));
}
EXPORT_SYMBOL_GPL(nvmem_cell_read_u8);

/**
 * nvmem_cell_read_u16() - Read a cell value as a u16
 *
 * @dev: Device that requests the nvmem cell.
 * @cell_id: Name of nvmem cell to read.
 * @val: pointer to output value.
 *
 * Return: 0 on success or negative errno.
 */
int nvmem_cell_read_u16(struct device *dev, const char *cell_id, u16 *val)
{
	return nvmem_cell_read_common(dev, cell_id, val, sizeof(*val));
}
EXPORT_SYMBOL_GPL(nvmem_cell_read_u16);

/**
 * nvmem_cell_read_u32() - Read a cell value as a u32
 *
 * @dev: Device that requests the nvmem cell.
 * @cell_id: Name of nvmem cell to read.
 * @val: pointer to output value.
 *
 * Return: 0 on success or negative errno.
 */
int nvmem_cell_read_u32(struct device *dev, const char *cell_id, u32 *val)
{
	return nvmem_cell_read_common(dev, cell_id, val, sizeof(*val));
}
EXPORT_SYMBOL_GPL(nvmem_cell_read_u32);

/**
 * nvmem_cell_read_u64() - Read a cell value as a u64
 *
 * @dev: Device that requests the nvmem cell.
 * @cell_id: Name of nvmem cell to read.
 * @val: pointer to output value.
 *
 * Return: 0 on success or negative errno.
 */
int nvmem_cell_read_u64(struct device *dev, const char *cell_id, u64 *val)
{
	return nvmem_cell_read_common(dev, cell_id, val, sizeof(*val));
}
EXPORT_SYMBOL_GPL(nvmem_cell_read_u64);

static const void *nvmem_cell_read_variable_common(struct device *dev,
						   const char *cell_id,
						   size_t max_len, size_t *len)
{
	struct nvmem_cell *cell;
	int nbits;
	void *buf;

	cell = nvmem_cell_get(dev, cell_id);
	if (IS_ERR(cell))
		return cell;

	nbits = cell->entry->nbits;
	buf = nvmem_cell_read(cell, len);
	nvmem_cell_put(cell);
	if (IS_ERR(buf))
		return buf;

	/*
	 * If nbits is set then nvmem_cell_read() can significantly exaggerate
	 * the length of the real data. Throw away the extra junk.
	 */
	if (nbits)
		*len = DIV_ROUND_UP(nbits, 8);

	if (*len > max_len) {
		kfree(buf);
		return ERR_PTR(-ERANGE);
	}

	return buf;
}

/**
 * nvmem_cell_read_variable_le_u32() - Read up to 32-bits of data as a little endian number.
 *
 * @dev: Device that requests the nvmem cell.
 * @cell_id: Name of nvmem cell to read.
 * @val: pointer to output value.
 *
 * Return: 0 on success or negative errno.
 */
int nvmem_cell_read_variable_le_u32(struct device *dev, const char *cell_id,
				    u32 *val)
{
	size_t len;
	const u8 *buf;
	int i;

	buf = nvmem_cell_read_variable_common(dev, cell_id, sizeof(*val), &len);
	if (IS_ERR(buf))
		return PTR_ERR(buf);

	/* Copy w/ implicit endian conversion */
	*val = 0;
	for (i = 0; i < len; i++)
		*val |= buf[i] << (8 * i);

	kfree(buf);

	return 0;
}
EXPORT_SYMBOL_GPL(nvmem_cell_read_variable_le_u32);

/**
 * nvmem_cell_read_variable_le_u64() - Read up to 64-bits of data as a little endian number.
 *
 * @dev: Device that requests the nvmem cell.
 * @cell_id: Name of nvmem cell to read.
 * @val: pointer to output value.
 *
 * Return: 0 on success or negative errno.
 */
int nvmem_cell_read_variable_le_u64(struct device *dev, const char *cell_id,
				    u64 *val)
{
	size_t len;
	const u8 *buf;
	int i;

	buf = nvmem_cell_read_variable_common(dev, cell_id, sizeof(*val), &len);
	if (IS_ERR(buf))
		return PTR_ERR(buf);

	/* Copy w/ implicit endian conversion */
	*val = 0;
	for (i = 0; i < len; i++)
		*val |= (uint64_t)buf[i] << (8 * i);

	kfree(buf);

	return 0;
}
EXPORT_SYMBOL_GPL(nvmem_cell_read_variable_le_u64);

/**
 * nvmem_device_cell_read() - Read a given nvmem device and cell
 *
 * @nvmem: nvmem device to read from.
 * @info: nvmem cell info to be read.
 * @buf: buffer pointer which will be populated on successful read.
 *
 * Return: length of successful bytes read on success and negative
 * error code on error.
 */
ssize_t nvmem_device_cell_read(struct nvmem_device *nvmem,
			   struct nvmem_cell_info *info, void *buf)
{
	struct nvmem_cell_entry cell;
	int rc;
	ssize_t len;

	if (!nvmem)
		return -EINVAL;

	rc = nvmem_cell_info_to_nvmem_cell_entry_nodup(nvmem, info, &cell);
	if (rc)
		return rc;

	rc = __nvmem_cell_read(nvmem, &cell, buf, &len, NULL, 0);
	if (rc)
		return rc;

	return len;
}
EXPORT_SYMBOL_GPL(nvmem_device_cell_read);

/**
 * nvmem_device_cell_write() - Write cell to a given nvmem device
 *
 * @nvmem: nvmem device to be written to.
 * @info: nvmem cell info to be written.
 * @buf: buffer to be written to cell.
 *
 * Return: length of bytes written or negative error code on failure.
 */
int nvmem_device_cell_write(struct nvmem_device *nvmem,
			    struct nvmem_cell_info *info, void *buf)
{
	struct nvmem_cell_entry cell;
	int rc;

	if (!nvmem)
		return -EINVAL;

	rc = nvmem_cell_info_to_nvmem_cell_entry_nodup(nvmem, info, &cell);
	if (rc)
		return rc;

	return __nvmem_cell_entry_write(&cell, buf, cell.bytes);
}
EXPORT_SYMBOL_GPL(nvmem_device_cell_write);

/**
 * nvmem_device_read() - Read from a given nvmem device
 *
 * @nvmem: nvmem device to read from.
 * @offset: offset in nvmem device.
 * @bytes: number of bytes to read.
 * @buf: buffer pointer which will be populated on successful read.
 *
 * Return: length of successful bytes read on success and negative
 * error code on error.
 */
int nvmem_device_read(struct nvmem_device *nvmem,
		      unsigned int offset,
		      size_t bytes, void *buf)
{
	int rc;

	if (!nvmem)
		return -EINVAL;

	rc = nvmem_reg_read(nvmem, offset, buf, bytes);

	if (rc)
		return rc;

	return bytes;
}
EXPORT_SYMBOL_GPL(nvmem_device_read);

/**
 * nvmem_device_write() - Write cell to a given nvmem device
 *
 * @nvmem: nvmem device to be written to.
 * @offset: offset in nvmem device.
 * @bytes: number of bytes to write.
 * @buf: buffer to be written.
 *
 * Return: length of bytes written or negative error code on failure.
 */
int nvmem_device_write(struct nvmem_device *nvmem,
		       unsigned int offset,
		       size_t bytes, void *buf)
{
	int rc;

	if (!nvmem)
		return -EINVAL;

	rc = nvmem_reg_write(nvmem, offset, buf, bytes);

	if (rc)
		return rc;


	return bytes;
}
EXPORT_SYMBOL_GPL(nvmem_device_write);

/**
 * nvmem_add_cell_table() - register a table of cell info entries
 *
 * @table: table of cell info entries
 */
void nvmem_add_cell_table(struct nvmem_cell_table *table)
{
	mutex_lock(&nvmem_cell_mutex);
	list_add_tail(&table->node, &nvmem_cell_tables);
	mutex_unlock(&nvmem_cell_mutex);
}
EXPORT_SYMBOL_GPL(nvmem_add_cell_table);

/**
 * nvmem_del_cell_table() - remove a previously registered cell info table
 *
 * @table: table of cell info entries
 */
void nvmem_del_cell_table(struct nvmem_cell_table *table)
{
	mutex_lock(&nvmem_cell_mutex);
	list_del(&table->node);
	mutex_unlock(&nvmem_cell_mutex);
}
EXPORT_SYMBOL_GPL(nvmem_del_cell_table);

/**
 * nvmem_add_cell_lookups() - register a list of cell lookup entries
 *
 * @entries: array of cell lookup entries
 * @nentries: number of cell lookup entries in the array
 */
void nvmem_add_cell_lookups(struct nvmem_cell_lookup *entries, size_t nentries)
{
	int i;

	mutex_lock(&nvmem_lookup_mutex);
	for (i = 0; i < nentries; i++)
		list_add_tail(&entries[i].node, &nvmem_lookup_list);
	mutex_unlock(&nvmem_lookup_mutex);
}
EXPORT_SYMBOL_GPL(nvmem_add_cell_lookups);

/**
 * nvmem_del_cell_lookups() - remove a list of previously added cell lookup
 *                            entries
 *
 * @entries: array of cell lookup entries
 * @nentries: number of cell lookup entries in the array
 */
void nvmem_del_cell_lookups(struct nvmem_cell_lookup *entries, size_t nentries)
{
	int i;

	mutex_lock(&nvmem_lookup_mutex);
	for (i = 0; i < nentries; i++)
		list_del(&entries[i].node);
	mutex_unlock(&nvmem_lookup_mutex);
}
EXPORT_SYMBOL_GPL(nvmem_del_cell_lookups);

/**
 * nvmem_dev_name() - Get the name of a given nvmem device.
 *
 * @nvmem: nvmem device.
 *
 * Return: name of the nvmem device.
 */
const char *nvmem_dev_name(struct nvmem_device *nvmem)
{
	return dev_name(&nvmem->dev);
}
EXPORT_SYMBOL_GPL(nvmem_dev_name);

/**
 * nvmem_dev_size() - Get the size of a given nvmem device.
 *
 * @nvmem: nvmem device.
 *
 * Return: size of the nvmem device.
 */
size_t nvmem_dev_size(struct nvmem_device *nvmem)
{
	return nvmem->size;
}
EXPORT_SYMBOL_GPL(nvmem_dev_size);

static int __init nvmem_init(void)
{
	int ret;

	ret = bus_register(&nvmem_bus_type);
	if (ret)
		return ret;

	ret = nvmem_layout_bus_register();
	if (ret)
		bus_unregister(&nvmem_bus_type);

	return ret;
}

static void __exit nvmem_exit(void)
{
	nvmem_layout_bus_unregister();
	bus_unregister(&nvmem_bus_type);
}

subsys_initcall(nvmem_init);
module_exit(nvmem_exit);

MODULE_AUTHOR("Srinivas Kandagatla <srinivas.kandagatla@linaro.org");
MODULE_AUTHOR("Maxime Ripard <maxime.ripard@free-electrons.com");
MODULE_DESCRIPTION("nvmem Driver Core");