summaryrefslogtreecommitdiff
path: root/drivers/gpio/gpiolib.c
blob: b73c39f998588388ed58bb10c5d376406572acc5 (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
2212
2213
2214
2215
2216
2217
2218
2219
2220
2221
2222
2223
2224
2225
2226
2227
2228
2229
2230
2231
2232
2233
2234
2235
2236
2237
2238
2239
2240
2241
2242
2243
2244
2245
2246
2247
2248
2249
2250
2251
2252
2253
2254
2255
2256
2257
2258
2259
2260
2261
2262
2263
2264
2265
2266
2267
2268
2269
2270
2271
2272
2273
2274
2275
2276
2277
2278
2279
2280
2281
2282
2283
2284
2285
2286
2287
2288
2289
2290
2291
2292
2293
2294
2295
2296
2297
2298
2299
2300
2301
2302
2303
2304
2305
2306
2307
2308
2309
2310
2311
2312
2313
2314
2315
2316
2317
2318
2319
2320
2321
2322
2323
2324
2325
2326
2327
2328
2329
2330
2331
2332
2333
2334
2335
2336
2337
2338
2339
2340
2341
2342
2343
2344
2345
2346
2347
2348
2349
2350
2351
2352
2353
2354
2355
2356
2357
2358
2359
2360
2361
2362
2363
2364
2365
2366
2367
2368
2369
2370
2371
2372
2373
2374
2375
2376
2377
2378
2379
2380
2381
2382
2383
2384
2385
2386
2387
2388
2389
2390
2391
2392
2393
2394
2395
2396
2397
2398
2399
2400
2401
2402
2403
2404
2405
2406
2407
2408
2409
2410
2411
2412
2413
2414
2415
2416
2417
2418
2419
2420
2421
2422
2423
2424
2425
2426
2427
2428
2429
2430
2431
2432
2433
2434
2435
2436
2437
2438
2439
2440
2441
2442
2443
2444
2445
2446
2447
2448
2449
2450
2451
2452
2453
2454
2455
2456
2457
2458
2459
2460
2461
2462
2463
2464
2465
2466
2467
2468
2469
2470
2471
2472
2473
2474
2475
2476
2477
2478
2479
2480
2481
2482
2483
2484
2485
2486
2487
2488
2489
2490
2491
2492
2493
2494
2495
2496
2497
2498
2499
2500
2501
2502
2503
2504
2505
2506
2507
2508
2509
2510
2511
2512
2513
2514
2515
2516
2517
2518
2519
2520
2521
2522
2523
2524
2525
2526
2527
2528
2529
2530
2531
2532
2533
2534
2535
2536
2537
2538
2539
2540
2541
2542
2543
2544
2545
2546
2547
2548
2549
2550
2551
2552
2553
2554
2555
2556
2557
2558
2559
2560
2561
2562
2563
2564
2565
2566
2567
2568
2569
2570
2571
2572
2573
2574
2575
2576
2577
2578
2579
2580
2581
2582
2583
2584
2585
2586
2587
2588
2589
2590
2591
2592
2593
2594
2595
2596
#include <linux/kernel.h>
#include <linux/module.h>
#include <linux/interrupt.h>
#include <linux/irq.h>
#include <linux/spinlock.h>
#include <linux/list.h>
#include <linux/device.h>
#include <linux/err.h>
#include <linux/debugfs.h>
#include <linux/seq_file.h>
#include <linux/gpio.h>
#include <linux/of_gpio.h>
#include <linux/acpi_gpio.h>
#include <linux/idr.h>
#include <linux/slab.h>
#include <linux/acpi.h>
#include <linux/gpio/driver.h>

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

/* Implementation infrastructure for GPIO interfaces.
 *
 * The GPIO programming interface allows for inlining speed-critical
 * get/set operations for common cases, so that access to SOC-integrated
 * GPIOs can sometimes cost only an instruction or two per bit.
 */


/* When debugging, extend minimal trust to callers and platform code.
 * Also emit diagnostic messages that may help initial bringup, when
 * board setup or driver bugs are most common.
 *
 * Otherwise, minimize overhead in what may be bitbanging codepaths.
 */
#ifdef	DEBUG
#define	extra_checks	1
#else
#define	extra_checks	0
#endif

/* gpio_lock prevents conflicts during gpio_desc[] table updates.
 * While any GPIO is requested, its gpio_chip is not removable;
 * each GPIO's "requested" flag serves as a lock and refcount.
 */
static DEFINE_SPINLOCK(gpio_lock);

struct gpio_desc {
	struct gpio_chip	*chip;
	unsigned long		flags;
/* flag symbols are bit numbers */
#define FLAG_REQUESTED	0
#define FLAG_IS_OUT	1
#define FLAG_EXPORT	2	/* protected by sysfs_lock */
#define FLAG_SYSFS	3	/* exported via /sys/class/gpio/control */
#define FLAG_TRIG_FALL	4	/* trigger on falling edge */
#define FLAG_TRIG_RISE	5	/* trigger on rising edge */
#define FLAG_ACTIVE_LOW	6	/* value has active low */
#define FLAG_OPEN_DRAIN	7	/* Gpio is open drain type */
#define FLAG_OPEN_SOURCE 8	/* Gpio is open source type */
#define FLAG_USED_AS_IRQ 9	/* GPIO is connected to an IRQ */

#define ID_SHIFT	16	/* add new flags before this one */

#define GPIO_FLAGS_MASK		((1 << ID_SHIFT) - 1)
#define GPIO_TRIGGER_MASK	(BIT(FLAG_TRIG_FALL) | BIT(FLAG_TRIG_RISE))

#ifdef CONFIG_DEBUG_FS
	const char		*label;
#endif
};
static struct gpio_desc gpio_desc[ARCH_NR_GPIOS];

#define GPIO_OFFSET_VALID(chip, offset) (offset >= 0 && offset < chip->ngpio)

static DEFINE_MUTEX(gpio_lookup_lock);
static LIST_HEAD(gpio_lookup_list);
static LIST_HEAD(gpio_chips);

#ifdef CONFIG_GPIO_SYSFS
static DEFINE_IDR(dirent_idr);
#endif

static int gpiod_request(struct gpio_desc *desc, const char *label);
static void gpiod_free(struct gpio_desc *desc);

#ifdef CONFIG_DEBUG_FS
#define gpiod_emerg(desc, fmt, ...)			                \
	pr_emerg("gpio-%d (%s): " fmt, desc_to_gpio(desc), desc->label, \
                 ##__VA_ARGS__)
#define gpiod_crit(desc, fmt, ...)			                \
	pr_crit("gpio-%d (%s): " fmt, desc_to_gpio(desc), desc->label,  \
                 ##__VA_ARGS__)
#define gpiod_err(desc, fmt, ...)				        \
	pr_err("gpio-%d (%s): " fmt, desc_to_gpio(desc), desc->label,   \
                 ##__VA_ARGS__)
#define gpiod_warn(desc, fmt, ...)				        \
	pr_warn("gpio-%d (%s): " fmt, desc_to_gpio(desc), desc->label,  \
                 ##__VA_ARGS__)
#define gpiod_info(desc, fmt, ...)				        \
	pr_info("gpio-%d (%s): " fmt, desc_to_gpio(desc), desc->label,  \
                ##__VA_ARGS__)
#define gpiod_dbg(desc, fmt, ...)				   \
	pr_debug("gpio-%d (%s): " fmt, desc_to_gpio(desc), desc->label, \
                 ##__VA_ARGS__)
#else
#define gpiod_emerg(desc, fmt, ...)			           \
	pr_emerg("gpio-%d: " fmt, desc_to_gpio(desc), ##__VA_ARGS__)
#define gpiod_crit(desc, fmt, ...)			           \
	pr_crit("gpio-%d: " fmt, desc_to_gpio(desc), ##__VA_ARGS__)
#define gpiod_err(desc, fmt, ...)				   \
	pr_err("gpio-%d: " fmt, desc_to_gpio(desc), ##__VA_ARGS__)
#define gpiod_warn(desc, fmt, ...)				   \
	pr_warn("gpio-%d: " fmt, desc_to_gpio(desc), ##__VA_ARGS__)
#define gpiod_info(desc, fmt, ...)				   \
	pr_info("gpio-%d: " fmt, desc_to_gpio(desc), ##__VA_ARGS__)
#define gpiod_dbg(desc, fmt, ...)				   \
	pr_debug("gpio-%d: " fmt, desc_to_gpio(desc), ##__VA_ARGS__)
#endif

static inline void desc_set_label(struct gpio_desc *d, const char *label)
{
#ifdef CONFIG_DEBUG_FS
	d->label = label;
#endif
}

/*
 * Return the GPIO number of the passed descriptor relative to its chip
 */
static int gpio_chip_hwgpio(const struct gpio_desc *desc)
{
	return desc - &desc->chip->desc[0];
}

/**
 * Convert a GPIO number to its descriptor
 */
struct gpio_desc *gpio_to_desc(unsigned gpio)
{
	if (WARN(!gpio_is_valid(gpio), "invalid GPIO %d\n", gpio))
		return NULL;
	else
		return &gpio_desc[gpio];
}
EXPORT_SYMBOL_GPL(gpio_to_desc);

/**
 * Convert an offset on a certain chip to a corresponding descriptor
 */
static struct gpio_desc *gpiochip_offset_to_desc(struct gpio_chip *chip,
						 unsigned int offset)
{
	unsigned int gpio = chip->base + offset;

	return gpio_to_desc(gpio);
}

/**
 * Convert a GPIO descriptor to the integer namespace.
 * This should disappear in the future but is needed since we still
 * use GPIO numbers for error messages and sysfs nodes
 */
int desc_to_gpio(const struct gpio_desc *desc)
{
	return desc - &gpio_desc[0];
}
EXPORT_SYMBOL_GPL(desc_to_gpio);


/* Warn when drivers omit gpio_request() calls -- legal but ill-advised
 * when setting direction, and otherwise illegal.  Until board setup code
 * and drivers use explicit requests everywhere (which won't happen when
 * those calls have no teeth) we can't avoid autorequesting.  This nag
 * message should motivate switching to explicit requests... so should
 * the weaker cleanup after faults, compared to gpio_request().
 *
 * NOTE: the autorequest mechanism is going away; at this point it's
 * only "legal" in the sense that (old) code using it won't break yet,
 * but instead only triggers a WARN() stack dump.
 */
static int gpio_ensure_requested(struct gpio_desc *desc)
{
	const struct gpio_chip *chip = desc->chip;
	const int gpio = desc_to_gpio(desc);

	if (WARN(test_and_set_bit(FLAG_REQUESTED, &desc->flags) == 0,
			"autorequest GPIO-%d\n", gpio)) {
		if (!try_module_get(chip->owner)) {
			pr_err("GPIO-%d: module can't be gotten \n", gpio);
			clear_bit(FLAG_REQUESTED, &desc->flags);
			/* lose */
			return -EIO;
		}
		desc_set_label(desc, "[auto]");
		/* caller must chip->request() w/o spinlock */
		if (chip->request)
			return 1;
	}
	return 0;
}

/**
 * gpiod_to_chip - Return the GPIO chip to which a GPIO descriptor belongs
 * @desc:	descriptor to return the chip of
 */
struct gpio_chip *gpiod_to_chip(const struct gpio_desc *desc)
{
	return desc ? desc->chip : NULL;
}
EXPORT_SYMBOL_GPL(gpiod_to_chip);

/* dynamic allocation of GPIOs, e.g. on a hotplugged device */
static int gpiochip_find_base(int ngpio)
{
	struct gpio_chip *chip;
	int base = ARCH_NR_GPIOS - ngpio;

	list_for_each_entry_reverse(chip, &gpio_chips, list) {
		/* found a free space? */
		if (chip->base + chip->ngpio <= base)
			break;
		else
			/* nope, check the space right before the chip */
			base = chip->base - ngpio;
	}

	if (gpio_is_valid(base)) {
		pr_debug("%s: found new base at %d\n", __func__, base);
		return base;
	} else {
		pr_err("%s: cannot find free range\n", __func__);
		return -ENOSPC;
	}
}

/**
 * gpiod_get_direction - return the current direction of a GPIO
 * @desc:	GPIO to get the direction of
 *
 * Return GPIOF_DIR_IN or GPIOF_DIR_OUT, or an error code in case of error.
 *
 * This function may sleep if gpiod_cansleep() is true.
 */
int gpiod_get_direction(const struct gpio_desc *desc)
{
	struct gpio_chip	*chip;
	unsigned		offset;
	int			status = -EINVAL;

	chip = gpiod_to_chip(desc);
	offset = gpio_chip_hwgpio(desc);

	if (!chip->get_direction)
		return status;

	status = chip->get_direction(chip, offset);
	if (status > 0) {
		/* GPIOF_DIR_IN, or other positive */
		status = 1;
		/* FLAG_IS_OUT is just a cache of the result of get_direction(),
		 * so it does not affect constness per se */
		clear_bit(FLAG_IS_OUT, &((struct gpio_desc *)desc)->flags);
	}
	if (status == 0) {
		/* GPIOF_DIR_OUT */
		set_bit(FLAG_IS_OUT, &((struct gpio_desc *)desc)->flags);
	}
	return status;
}
EXPORT_SYMBOL_GPL(gpiod_get_direction);

#ifdef CONFIG_GPIO_SYSFS

/* lock protects against unexport_gpio() being called while
 * sysfs files are active.
 */
static DEFINE_MUTEX(sysfs_lock);

/*
 * /sys/class/gpio/gpioN... only for GPIOs that are exported
 *   /direction
 *      * MAY BE OMITTED if kernel won't allow direction changes
 *      * is read/write as "in" or "out"
 *      * may also be written as "high" or "low", initializing
 *        output value as specified ("out" implies "low")
 *   /value
 *      * always readable, subject to hardware behavior
 *      * may be writable, as zero/nonzero
 *   /edge
 *      * configures behavior of poll(2) on /value
 *      * available only if pin can generate IRQs on input
 *      * is read/write as "none", "falling", "rising", or "both"
 *   /active_low
 *      * configures polarity of /value
 *      * is read/write as zero/nonzero
 *      * also affects existing and subsequent "falling" and "rising"
 *        /edge configuration
 */

static ssize_t gpio_direction_show(struct device *dev,
		struct device_attribute *attr, char *buf)
{
	const struct gpio_desc	*desc = dev_get_drvdata(dev);
	ssize_t			status;

	mutex_lock(&sysfs_lock);

	if (!test_bit(FLAG_EXPORT, &desc->flags)) {
		status = -EIO;
	} else {
		gpiod_get_direction(desc);
		status = sprintf(buf, "%s\n",
			test_bit(FLAG_IS_OUT, &desc->flags)
				? "out" : "in");
	}

	mutex_unlock(&sysfs_lock);
	return status;
}

static ssize_t gpio_direction_store(struct device *dev,
		struct device_attribute *attr, const char *buf, size_t size)
{
	struct gpio_desc	*desc = dev_get_drvdata(dev);
	ssize_t			status;

	mutex_lock(&sysfs_lock);

	if (!test_bit(FLAG_EXPORT, &desc->flags))
		status = -EIO;
	else if (sysfs_streq(buf, "high"))
		status = gpiod_direction_output(desc, 1);
	else if (sysfs_streq(buf, "out") || sysfs_streq(buf, "low"))
		status = gpiod_direction_output(desc, 0);
	else if (sysfs_streq(buf, "in"))
		status = gpiod_direction_input(desc);
	else
		status = -EINVAL;

	mutex_unlock(&sysfs_lock);
	return status ? : size;
}

static /* const */ DEVICE_ATTR(direction, 0644,
		gpio_direction_show, gpio_direction_store);

static ssize_t gpio_value_show(struct device *dev,
		struct device_attribute *attr, char *buf)
{
	struct gpio_desc	*desc = dev_get_drvdata(dev);
	ssize_t			status;

	mutex_lock(&sysfs_lock);

	if (!test_bit(FLAG_EXPORT, &desc->flags))
		status = -EIO;
	else
		status = sprintf(buf, "%d\n", gpiod_get_value_cansleep(desc));

	mutex_unlock(&sysfs_lock);
	return status;
}

static ssize_t gpio_value_store(struct device *dev,
		struct device_attribute *attr, const char *buf, size_t size)
{
	struct gpio_desc	*desc = dev_get_drvdata(dev);
	ssize_t			status;

	mutex_lock(&sysfs_lock);

	if (!test_bit(FLAG_EXPORT, &desc->flags))
		status = -EIO;
	else if (!test_bit(FLAG_IS_OUT, &desc->flags))
		status = -EPERM;
	else {
		long		value;

		status = kstrtol(buf, 0, &value);
		if (status == 0) {
			gpiod_set_value_cansleep(desc, value);
			status = size;
		}
	}

	mutex_unlock(&sysfs_lock);
	return status;
}

static const DEVICE_ATTR(value, 0644,
		gpio_value_show, gpio_value_store);

static irqreturn_t gpio_sysfs_irq(int irq, void *priv)
{
	struct sysfs_dirent	*value_sd = priv;

	sysfs_notify_dirent(value_sd);
	return IRQ_HANDLED;
}

static int gpio_setup_irq(struct gpio_desc *desc, struct device *dev,
		unsigned long gpio_flags)
{
	struct sysfs_dirent	*value_sd;
	unsigned long		irq_flags;
	int			ret, irq, id;

	if ((desc->flags & GPIO_TRIGGER_MASK) == gpio_flags)
		return 0;

	irq = gpiod_to_irq(desc);
	if (irq < 0)
		return -EIO;

	id = desc->flags >> ID_SHIFT;
	value_sd = idr_find(&dirent_idr, id);
	if (value_sd)
		free_irq(irq, value_sd);

	desc->flags &= ~GPIO_TRIGGER_MASK;

	if (!gpio_flags) {
		gpiod_unlock_as_irq(desc);
		ret = 0;
		goto free_id;
	}

	irq_flags = IRQF_SHARED;
	if (test_bit(FLAG_TRIG_FALL, &gpio_flags))
		irq_flags |= test_bit(FLAG_ACTIVE_LOW, &desc->flags) ?
			IRQF_TRIGGER_RISING : IRQF_TRIGGER_FALLING;
	if (test_bit(FLAG_TRIG_RISE, &gpio_flags))
		irq_flags |= test_bit(FLAG_ACTIVE_LOW, &desc->flags) ?
			IRQF_TRIGGER_FALLING : IRQF_TRIGGER_RISING;

	if (!value_sd) {
		value_sd = sysfs_get_dirent(dev->kobj.sd, "value");
		if (!value_sd) {
			ret = -ENODEV;
			goto err_out;
		}

		ret = idr_alloc(&dirent_idr, value_sd, 1, 0, GFP_KERNEL);
		if (ret < 0)
			goto free_sd;
		id = ret;

		desc->flags &= GPIO_FLAGS_MASK;
		desc->flags |= (unsigned long)id << ID_SHIFT;

		if (desc->flags >> ID_SHIFT != id) {
			ret = -ERANGE;
			goto free_id;
		}
	}

	ret = request_any_context_irq(irq, gpio_sysfs_irq, irq_flags,
				"gpiolib", value_sd);
	if (ret < 0)
		goto free_id;

	ret = gpiod_lock_as_irq(desc);
	if (ret < 0) {
		gpiod_warn(desc, "failed to flag the GPIO for IRQ\n");
		goto free_id;
	}

	desc->flags |= gpio_flags;
	return 0;

free_id:
	idr_remove(&dirent_idr, id);
	desc->flags &= GPIO_FLAGS_MASK;
free_sd:
	if (value_sd)
		sysfs_put(value_sd);
err_out:
	return ret;
}

static const struct {
	const char *name;
	unsigned long flags;
} trigger_types[] = {
	{ "none",    0 },
	{ "falling", BIT(FLAG_TRIG_FALL) },
	{ "rising",  BIT(FLAG_TRIG_RISE) },
	{ "both",    BIT(FLAG_TRIG_FALL) | BIT(FLAG_TRIG_RISE) },
};

static ssize_t gpio_edge_show(struct device *dev,
		struct device_attribute *attr, char *buf)
{
	const struct gpio_desc	*desc = dev_get_drvdata(dev);
	ssize_t			status;

	mutex_lock(&sysfs_lock);

	if (!test_bit(FLAG_EXPORT, &desc->flags))
		status = -EIO;
	else {
		int i;

		status = 0;
		for (i = 0; i < ARRAY_SIZE(trigger_types); i++)
			if ((desc->flags & GPIO_TRIGGER_MASK)
					== trigger_types[i].flags) {
				status = sprintf(buf, "%s\n",
						 trigger_types[i].name);
				break;
			}
	}

	mutex_unlock(&sysfs_lock);
	return status;
}

static ssize_t gpio_edge_store(struct device *dev,
		struct device_attribute *attr, const char *buf, size_t size)
{
	struct gpio_desc	*desc = dev_get_drvdata(dev);
	ssize_t			status;
	int			i;

	for (i = 0; i < ARRAY_SIZE(trigger_types); i++)
		if (sysfs_streq(trigger_types[i].name, buf))
			goto found;
	return -EINVAL;

found:
	mutex_lock(&sysfs_lock);

	if (!test_bit(FLAG_EXPORT, &desc->flags))
		status = -EIO;
	else {
		status = gpio_setup_irq(desc, dev, trigger_types[i].flags);
		if (!status)
			status = size;
	}

	mutex_unlock(&sysfs_lock);

	return status;
}

static DEVICE_ATTR(edge, 0644, gpio_edge_show, gpio_edge_store);

static int sysfs_set_active_low(struct gpio_desc *desc, struct device *dev,
				int value)
{
	int			status = 0;

	if (!!test_bit(FLAG_ACTIVE_LOW, &desc->flags) == !!value)
		return 0;

	if (value)
		set_bit(FLAG_ACTIVE_LOW, &desc->flags);
	else
		clear_bit(FLAG_ACTIVE_LOW, &desc->flags);

	/* reconfigure poll(2) support if enabled on one edge only */
	if (dev != NULL && (!!test_bit(FLAG_TRIG_RISE, &desc->flags) ^
				!!test_bit(FLAG_TRIG_FALL, &desc->flags))) {
		unsigned long trigger_flags = desc->flags & GPIO_TRIGGER_MASK;

		gpio_setup_irq(desc, dev, 0);
		status = gpio_setup_irq(desc, dev, trigger_flags);
	}

	return status;
}

static ssize_t gpio_active_low_show(struct device *dev,
		struct device_attribute *attr, char *buf)
{
	const struct gpio_desc	*desc = dev_get_drvdata(dev);
	ssize_t			status;

	mutex_lock(&sysfs_lock);

	if (!test_bit(FLAG_EXPORT, &desc->flags))
		status = -EIO;
	else
		status = sprintf(buf, "%d\n",
				!!test_bit(FLAG_ACTIVE_LOW, &desc->flags));

	mutex_unlock(&sysfs_lock);

	return status;
}

static ssize_t gpio_active_low_store(struct device *dev,
		struct device_attribute *attr, const char *buf, size_t size)
{
	struct gpio_desc	*desc = dev_get_drvdata(dev);
	ssize_t			status;

	mutex_lock(&sysfs_lock);

	if (!test_bit(FLAG_EXPORT, &desc->flags)) {
		status = -EIO;
	} else {
		long		value;

		status = kstrtol(buf, 0, &value);
		if (status == 0)
			status = sysfs_set_active_low(desc, dev, value != 0);
	}

	mutex_unlock(&sysfs_lock);

	return status ? : size;
}

static const DEVICE_ATTR(active_low, 0644,
		gpio_active_low_show, gpio_active_low_store);

static const struct attribute *gpio_attrs[] = {
	&dev_attr_value.attr,
	&dev_attr_active_low.attr,
	NULL,
};

static const struct attribute_group gpio_attr_group = {
	.attrs = (struct attribute **) gpio_attrs,
};

/*
 * /sys/class/gpio/gpiochipN/
 *   /base ... matching gpio_chip.base (N)
 *   /label ... matching gpio_chip.label
 *   /ngpio ... matching gpio_chip.ngpio
 */

static ssize_t chip_base_show(struct device *dev,
			       struct device_attribute *attr, char *buf)
{
	const struct gpio_chip	*chip = dev_get_drvdata(dev);

	return sprintf(buf, "%d\n", chip->base);
}
static DEVICE_ATTR(base, 0444, chip_base_show, NULL);

static ssize_t chip_label_show(struct device *dev,
			       struct device_attribute *attr, char *buf)
{
	const struct gpio_chip	*chip = dev_get_drvdata(dev);

	return sprintf(buf, "%s\n", chip->label ? : "");
}
static DEVICE_ATTR(label, 0444, chip_label_show, NULL);

static ssize_t chip_ngpio_show(struct device *dev,
			       struct device_attribute *attr, char *buf)
{
	const struct gpio_chip	*chip = dev_get_drvdata(dev);

	return sprintf(buf, "%u\n", chip->ngpio);
}
static DEVICE_ATTR(ngpio, 0444, chip_ngpio_show, NULL);

static const struct attribute *gpiochip_attrs[] = {
	&dev_attr_base.attr,
	&dev_attr_label.attr,
	&dev_attr_ngpio.attr,
	NULL,
};

static const struct attribute_group gpiochip_attr_group = {
	.attrs = (struct attribute **) gpiochip_attrs,
};

/*
 * /sys/class/gpio/export ... write-only
 *	integer N ... number of GPIO to export (full access)
 * /sys/class/gpio/unexport ... write-only
 *	integer N ... number of GPIO to unexport
 */
static ssize_t export_store(struct class *class,
				struct class_attribute *attr,
				const char *buf, size_t len)
{
	long			gpio;
	struct gpio_desc	*desc;
	int			status;

	status = kstrtol(buf, 0, &gpio);
	if (status < 0)
		goto done;

	desc = gpio_to_desc(gpio);
	/* reject invalid GPIOs */
	if (!desc) {
		pr_warn("%s: invalid GPIO %ld\n", __func__, gpio);
		return -EINVAL;
	}

	/* No extra locking here; FLAG_SYSFS just signifies that the
	 * request and export were done by on behalf of userspace, so
	 * they may be undone on its behalf too.
	 */

	status = gpiod_request(desc, "sysfs");
	if (status < 0) {
		if (status == -EPROBE_DEFER)
			status = -ENODEV;
		goto done;
	}
	status = gpiod_export(desc, true);
	if (status < 0)
		gpiod_free(desc);
	else
		set_bit(FLAG_SYSFS, &desc->flags);

done:
	if (status)
		pr_debug("%s: status %d\n", __func__, status);
	return status ? : len;
}

static ssize_t unexport_store(struct class *class,
				struct class_attribute *attr,
				const char *buf, size_t len)
{
	long			gpio;
	struct gpio_desc	*desc;
	int			status;

	status = kstrtol(buf, 0, &gpio);
	if (status < 0)
		goto done;

	desc = gpio_to_desc(gpio);
	/* reject bogus commands (gpio_unexport ignores them) */
	if (!desc) {
		pr_warn("%s: invalid GPIO %ld\n", __func__, gpio);
		return -EINVAL;
	}

	status = -EINVAL;

	/* No extra locking here; FLAG_SYSFS just signifies that the
	 * request and export were done by on behalf of userspace, so
	 * they may be undone on its behalf too.
	 */
	if (test_and_clear_bit(FLAG_SYSFS, &desc->flags)) {
		status = 0;
		gpiod_free(desc);
	}
done:
	if (status)
		pr_debug("%s: status %d\n", __func__, status);
	return status ? : len;
}

static struct class_attribute gpio_class_attrs[] = {
	__ATTR(export, 0200, NULL, export_store),
	__ATTR(unexport, 0200, NULL, unexport_store),
	__ATTR_NULL,
};

static struct class gpio_class = {
	.name =		"gpio",
	.owner =	THIS_MODULE,

	.class_attrs =	gpio_class_attrs,
};


/**
 * gpiod_export - export a GPIO through sysfs
 * @gpio: gpio to make available, already requested
 * @direction_may_change: true if userspace may change gpio direction
 * Context: arch_initcall or later
 *
 * When drivers want to make a GPIO accessible to userspace after they
 * have requested it -- perhaps while debugging, or as part of their
 * public interface -- they may use this routine.  If the GPIO can
 * change direction (some can't) and the caller allows it, userspace
 * will see "direction" sysfs attribute which may be used to change
 * the gpio's direction.  A "value" attribute will always be provided.
 *
 * Returns zero on success, else an error.
 */
int gpiod_export(struct gpio_desc *desc, bool direction_may_change)
{
	unsigned long		flags;
	int			status;
	const char		*ioname = NULL;
	struct device		*dev;
	int			offset;

	/* can't export until sysfs is available ... */
	if (!gpio_class.p) {
		pr_debug("%s: called too early!\n", __func__);
		return -ENOENT;
	}

	if (!desc) {
		pr_debug("%s: invalid gpio descriptor\n", __func__);
		return -EINVAL;
	}

	mutex_lock(&sysfs_lock);

	spin_lock_irqsave(&gpio_lock, flags);
	if (!test_bit(FLAG_REQUESTED, &desc->flags) ||
	     test_bit(FLAG_EXPORT, &desc->flags)) {
		spin_unlock_irqrestore(&gpio_lock, flags);
		pr_debug("%s: gpio %d unavailable (requested=%d, exported=%d)\n",
				__func__, desc_to_gpio(desc),
				test_bit(FLAG_REQUESTED, &desc->flags),
				test_bit(FLAG_EXPORT, &desc->flags));
		status = -EPERM;
		goto fail_unlock;
	}

	if (!desc->chip->direction_input || !desc->chip->direction_output)
		direction_may_change = false;
	spin_unlock_irqrestore(&gpio_lock, flags);

	offset = gpio_chip_hwgpio(desc);
	if (desc->chip->names && desc->chip->names[offset])
		ioname = desc->chip->names[offset];

	dev = device_create(&gpio_class, desc->chip->dev, MKDEV(0, 0),
			    desc, ioname ? ioname : "gpio%u",
			    desc_to_gpio(desc));
	if (IS_ERR(dev)) {
		status = PTR_ERR(dev);
		goto fail_unlock;
	}

	status = sysfs_create_group(&dev->kobj, &gpio_attr_group);
	if (status)
		goto fail_unregister_device;

	if (direction_may_change) {
		status = device_create_file(dev, &dev_attr_direction);
		if (status)
			goto fail_unregister_device;
	}

	if (gpiod_to_irq(desc) >= 0 && (direction_may_change ||
				       !test_bit(FLAG_IS_OUT, &desc->flags))) {
		status = device_create_file(dev, &dev_attr_edge);
		if (status)
			goto fail_unregister_device;
	}

	set_bit(FLAG_EXPORT, &desc->flags);
	mutex_unlock(&sysfs_lock);
	return 0;

fail_unregister_device:
	device_unregister(dev);
fail_unlock:
	mutex_unlock(&sysfs_lock);
	pr_debug("%s: gpio%d status %d\n", __func__, desc_to_gpio(desc),
		 status);
	return status;
}
EXPORT_SYMBOL_GPL(gpiod_export);

static int match_export(struct device *dev, const void *data)
{
	return dev_get_drvdata(dev) == data;
}

/**
 * gpiod_export_link - create a sysfs link to an exported GPIO node
 * @dev: device under which to create symlink
 * @name: name of the symlink
 * @gpio: gpio to create symlink to, already exported
 *
 * Set up a symlink from /sys/.../dev/name to /sys/class/gpio/gpioN
 * node. Caller is responsible for unlinking.
 *
 * Returns zero on success, else an error.
 */
int gpiod_export_link(struct device *dev, const char *name,
		      struct gpio_desc *desc)
{
	int			status = -EINVAL;

	if (!desc) {
		pr_warn("%s: invalid GPIO\n", __func__);
		return -EINVAL;
	}

	mutex_lock(&sysfs_lock);

	if (test_bit(FLAG_EXPORT, &desc->flags)) {
		struct device *tdev;

		tdev = class_find_device(&gpio_class, NULL, desc, match_export);
		if (tdev != NULL) {
			status = sysfs_create_link(&dev->kobj, &tdev->kobj,
						name);
		} else {
			status = -ENODEV;
		}
	}

	mutex_unlock(&sysfs_lock);

	if (status)
		pr_debug("%s: gpio%d status %d\n", __func__, desc_to_gpio(desc),
			 status);

	return status;
}
EXPORT_SYMBOL_GPL(gpiod_export_link);

/**
 * gpiod_sysfs_set_active_low - set the polarity of gpio sysfs value
 * @gpio: gpio to change
 * @value: non-zero to use active low, i.e. inverted values
 *
 * Set the polarity of /sys/class/gpio/gpioN/value sysfs attribute.
 * The GPIO does not have to be exported yet.  If poll(2) support has
 * been enabled for either rising or falling edge, it will be
 * reconfigured to follow the new polarity.
 *
 * Returns zero on success, else an error.
 */
int gpiod_sysfs_set_active_low(struct gpio_desc *desc, int value)
{
	struct device		*dev = NULL;
	int			status = -EINVAL;

	if (!desc) {
		pr_warn("%s: invalid GPIO\n", __func__);
		return -EINVAL;
	}

	mutex_lock(&sysfs_lock);

	if (test_bit(FLAG_EXPORT, &desc->flags)) {
		dev = class_find_device(&gpio_class, NULL, desc, match_export);
		if (dev == NULL) {
			status = -ENODEV;
			goto unlock;
		}
	}

	status = sysfs_set_active_low(desc, dev, value);

unlock:
	mutex_unlock(&sysfs_lock);

	if (status)
		pr_debug("%s: gpio%d status %d\n", __func__, desc_to_gpio(desc),
			 status);

	return status;
}
EXPORT_SYMBOL_GPL(gpiod_sysfs_set_active_low);

/**
 * gpiod_unexport - reverse effect of gpio_export()
 * @gpio: gpio to make unavailable
 *
 * This is implicit on gpio_free().
 */
void gpiod_unexport(struct gpio_desc *desc)
{
	int			status = 0;
	struct device		*dev = NULL;

	if (!desc) {
		pr_warn("%s: invalid GPIO\n", __func__);
		return;
	}

	mutex_lock(&sysfs_lock);

	if (test_bit(FLAG_EXPORT, &desc->flags)) {

		dev = class_find_device(&gpio_class, NULL, desc, match_export);
		if (dev) {
			gpio_setup_irq(desc, dev, 0);
			clear_bit(FLAG_EXPORT, &desc->flags);
		} else
			status = -ENODEV;
	}

	mutex_unlock(&sysfs_lock);

	if (dev) {
		device_unregister(dev);
		put_device(dev);
	}

	if (status)
		pr_debug("%s: gpio%d status %d\n", __func__, desc_to_gpio(desc),
			 status);
}
EXPORT_SYMBOL_GPL(gpiod_unexport);

static int gpiochip_export(struct gpio_chip *chip)
{
	int		status;
	struct device	*dev;

	/* Many systems register gpio chips for SOC support very early,
	 * before driver model support is available.  In those cases we
	 * export this later, in gpiolib_sysfs_init() ... here we just
	 * verify that _some_ field of gpio_class got initialized.
	 */
	if (!gpio_class.p)
		return 0;

	/* use chip->base for the ID; it's already known to be unique */
	mutex_lock(&sysfs_lock);
	dev = device_create(&gpio_class, chip->dev, MKDEV(0, 0), chip,
				"gpiochip%d", chip->base);
	if (!IS_ERR(dev)) {
		status = sysfs_create_group(&dev->kobj,
				&gpiochip_attr_group);
	} else
		status = PTR_ERR(dev);
	chip->exported = (status == 0);
	mutex_unlock(&sysfs_lock);

	if (status) {
		unsigned long	flags;
		unsigned	gpio;

		spin_lock_irqsave(&gpio_lock, flags);
		gpio = 0;
		while (gpio < chip->ngpio)
			chip->desc[gpio++].chip = NULL;
		spin_unlock_irqrestore(&gpio_lock, flags);

		pr_debug("%s: chip %s status %d\n", __func__,
				chip->label, status);
	}

	return status;
}

static void gpiochip_unexport(struct gpio_chip *chip)
{
	int			status;
	struct device		*dev;

	mutex_lock(&sysfs_lock);
	dev = class_find_device(&gpio_class, NULL, chip, match_export);
	if (dev) {
		put_device(dev);
		device_unregister(dev);
		chip->exported = 0;
		status = 0;
	} else
		status = -ENODEV;
	mutex_unlock(&sysfs_lock);

	if (status)
		pr_debug("%s: chip %s status %d\n", __func__,
				chip->label, status);
}

static int __init gpiolib_sysfs_init(void)
{
	int		status;
	unsigned long	flags;
	struct gpio_chip *chip;

	status = class_register(&gpio_class);
	if (status < 0)
		return status;

	/* Scan and register the gpio_chips which registered very
	 * early (e.g. before the class_register above was called).
	 *
	 * We run before arch_initcall() so chip->dev nodes can have
	 * registered, and so arch_initcall() can always gpio_export().
	 */
	spin_lock_irqsave(&gpio_lock, flags);
	list_for_each_entry(chip, &gpio_chips, list) {
		if (!chip || chip->exported)
			continue;

		spin_unlock_irqrestore(&gpio_lock, flags);
		status = gpiochip_export(chip);
		spin_lock_irqsave(&gpio_lock, flags);
	}
	spin_unlock_irqrestore(&gpio_lock, flags);


	return status;
}
postcore_initcall(gpiolib_sysfs_init);

#else
static inline int gpiochip_export(struct gpio_chip *chip)
{
	return 0;
}

static inline void gpiochip_unexport(struct gpio_chip *chip)
{
}

#endif /* CONFIG_GPIO_SYSFS */

/*
 * Add a new chip to the global chips list, keeping the list of chips sorted
 * by base order.
 *
 * Return -EBUSY if the new chip overlaps with some other chip's integer
 * space.
 */
static int gpiochip_add_to_list(struct gpio_chip *chip)
{
	struct list_head *pos = &gpio_chips;
	struct gpio_chip *_chip;
	int err = 0;

	/* find where to insert our chip */
	list_for_each(pos, &gpio_chips) {
		_chip = list_entry(pos, struct gpio_chip, list);
		/* shall we insert before _chip? */
		if (_chip->base >= chip->base + chip->ngpio)
			break;
	}

	/* are we stepping on the chip right before? */
	if (pos != &gpio_chips && pos->prev != &gpio_chips) {
		_chip = list_entry(pos->prev, struct gpio_chip, list);
		if (_chip->base + _chip->ngpio > chip->base) {
			dev_err(chip->dev,
			       "GPIO integer space overlap, cannot add chip\n");
			err = -EBUSY;
		}
	}

	if (!err)
		list_add_tail(&chip->list, pos);

	return err;
}

/**
 * gpiochip_add() - register a gpio_chip
 * @chip: the chip to register, with chip->base initialized
 * Context: potentially before irqs or kmalloc will work
 *
 * Returns a negative errno if the chip can't be registered, such as
 * because the chip->base is invalid or already associated with a
 * different chip.  Otherwise it returns zero as a success code.
 *
 * When gpiochip_add() is called very early during boot, so that GPIOs
 * can be freely used, the chip->dev device must be registered before
 * the gpio framework's arch_initcall().  Otherwise sysfs initialization
 * for GPIOs will fail rudely.
 *
 * If chip->base is negative, this requests dynamic assignment of
 * a range of valid GPIOs.
 */
int gpiochip_add(struct gpio_chip *chip)
{
	unsigned long	flags;
	int		status = 0;
	unsigned	id;
	int		base = chip->base;

	if ((!gpio_is_valid(base) || !gpio_is_valid(base + chip->ngpio - 1))
			&& base >= 0) {
		status = -EINVAL;
		goto fail;
	}

	spin_lock_irqsave(&gpio_lock, flags);

	if (base < 0) {
		base = gpiochip_find_base(chip->ngpio);
		if (base < 0) {
			status = base;
			goto unlock;
		}
		chip->base = base;
	}

	status = gpiochip_add_to_list(chip);

	if (status == 0) {
		chip->desc = &gpio_desc[chip->base];

		for (id = 0; id < chip->ngpio; id++) {
			struct gpio_desc *desc = &chip->desc[id];
			desc->chip = chip;

			/* REVISIT:  most hardware initializes GPIOs as
			 * inputs (often with pullups enabled) so power
			 * usage is minimized.  Linux code should set the
			 * gpio direction first thing; but until it does,
			 * and in case chip->get_direction is not set,
			 * we may expose the wrong direction in sysfs.
			 */
			desc->flags = !chip->direction_input
				? (1 << FLAG_IS_OUT)
				: 0;
		}
	}

	spin_unlock_irqrestore(&gpio_lock, flags);

#ifdef CONFIG_PINCTRL
	INIT_LIST_HEAD(&chip->pin_ranges);
#endif

	of_gpiochip_add(chip);

	if (status)
		goto fail;

	status = gpiochip_export(chip);
	if (status)
		goto fail;

	pr_debug("gpiochip_add: registered GPIOs %d to %d on device: %s\n",
		chip->base, chip->base + chip->ngpio - 1,
		chip->label ? : "generic");

	return 0;

unlock:
	spin_unlock_irqrestore(&gpio_lock, flags);
fail:
	/* failures here can mean systems won't boot... */
	pr_err("gpiochip_add: gpios %d..%d (%s) failed to register\n",
		chip->base, chip->base + chip->ngpio - 1,
		chip->label ? : "generic");
	return status;
}
EXPORT_SYMBOL_GPL(gpiochip_add);

/**
 * gpiochip_remove() - unregister a gpio_chip
 * @chip: the chip to unregister
 *
 * A gpio_chip with any GPIOs still requested may not be removed.
 */
int gpiochip_remove(struct gpio_chip *chip)
{
	unsigned long	flags;
	int		status = 0;
	unsigned	id;

	spin_lock_irqsave(&gpio_lock, flags);

	gpiochip_remove_pin_ranges(chip);
	of_gpiochip_remove(chip);

	for (id = 0; id < chip->ngpio; id++) {
		if (test_bit(FLAG_REQUESTED, &chip->desc[id].flags)) {
			status = -EBUSY;
			break;
		}
	}
	if (status == 0) {
		for (id = 0; id < chip->ngpio; id++)
			chip->desc[id].chip = NULL;

		list_del(&chip->list);
	}

	spin_unlock_irqrestore(&gpio_lock, flags);

	if (status == 0)
		gpiochip_unexport(chip);

	return status;
}
EXPORT_SYMBOL_GPL(gpiochip_remove);

/**
 * gpiochip_find() - iterator for locating a specific gpio_chip
 * @data: data to pass to match function
 * @callback: Callback function to check gpio_chip
 *
 * Similar to bus_find_device.  It returns a reference to a gpio_chip as
 * determined by a user supplied @match callback.  The callback should return
 * 0 if the device doesn't match and non-zero if it does.  If the callback is
 * non-zero, this function will return to the caller and not iterate over any
 * more gpio_chips.
 */
struct gpio_chip *gpiochip_find(void *data,
				int (*match)(struct gpio_chip *chip,
					     void *data))
{
	struct gpio_chip *chip;
	unsigned long flags;

	spin_lock_irqsave(&gpio_lock, flags);
	list_for_each_entry(chip, &gpio_chips, list)
		if (match(chip, data))
			break;

	/* No match? */
	if (&chip->list == &gpio_chips)
		chip = NULL;
	spin_unlock_irqrestore(&gpio_lock, flags);

	return chip;
}
EXPORT_SYMBOL_GPL(gpiochip_find);

static int gpiochip_match_name(struct gpio_chip *chip, void *data)
{
	const char *name = data;

	return !strcmp(chip->label, name);
}

static struct gpio_chip *find_chip_by_name(const char *name)
{
	return gpiochip_find((void *)name, gpiochip_match_name);
}

#ifdef CONFIG_PINCTRL

/**
 * gpiochip_add_pingroup_range() - add a range for GPIO <-> pin mapping
 * @chip: the gpiochip to add the range for
 * @pinctrl: the dev_name() of the pin controller to map to
 * @gpio_offset: the start offset in the current gpio_chip number space
 * @pin_group: name of the pin group inside the pin controller
 */
int gpiochip_add_pingroup_range(struct gpio_chip *chip,
			struct pinctrl_dev *pctldev,
			unsigned int gpio_offset, const char *pin_group)
{
	struct gpio_pin_range *pin_range;
	int ret;

	pin_range = kzalloc(sizeof(*pin_range), GFP_KERNEL);
	if (!pin_range) {
		pr_err("%s: GPIO chip: failed to allocate pin ranges\n",
				chip->label);
		return -ENOMEM;
	}

	/* Use local offset as range ID */
	pin_range->range.id = gpio_offset;
	pin_range->range.gc = chip;
	pin_range->range.name = chip->label;
	pin_range->range.base = chip->base + gpio_offset;
	pin_range->pctldev = pctldev;

	ret = pinctrl_get_group_pins(pctldev, pin_group,
					&pin_range->range.pins,
					&pin_range->range.npins);
	if (ret < 0) {
		kfree(pin_range);
		return ret;
	}

	pinctrl_add_gpio_range(pctldev, &pin_range->range);

	pr_debug("GPIO chip %s: created GPIO range %d->%d ==> %s PINGRP %s\n",
		 chip->label, gpio_offset,
		 gpio_offset + pin_range->range.npins - 1,
		 pinctrl_dev_get_devname(pctldev), pin_group);

	list_add_tail(&pin_range->node, &chip->pin_ranges);

	return 0;
}
EXPORT_SYMBOL_GPL(gpiochip_add_pingroup_range);

/**
 * gpiochip_add_pin_range() - add a range for GPIO <-> pin mapping
 * @chip: the gpiochip to add the range for
 * @pinctrl_name: the dev_name() of the pin controller to map to
 * @gpio_offset: the start offset in the current gpio_chip number space
 * @pin_offset: the start offset in the pin controller number space
 * @npins: the number of pins from the offset of each pin space (GPIO and
 *	pin controller) to accumulate in this range
 */
int gpiochip_add_pin_range(struct gpio_chip *chip, const char *pinctl_name,
			   unsigned int gpio_offset, unsigned int pin_offset,
			   unsigned int npins)
{
	struct gpio_pin_range *pin_range;
	int ret;

	pin_range = kzalloc(sizeof(*pin_range), GFP_KERNEL);
	if (!pin_range) {
		pr_err("%s: GPIO chip: failed to allocate pin ranges\n",
				chip->label);
		return -ENOMEM;
	}

	/* Use local offset as range ID */
	pin_range->range.id = gpio_offset;
	pin_range->range.gc = chip;
	pin_range->range.name = chip->label;
	pin_range->range.base = chip->base + gpio_offset;
	pin_range->range.pin_base = pin_offset;
	pin_range->range.npins = npins;
	pin_range->pctldev = pinctrl_find_and_add_gpio_range(pinctl_name,
			&pin_range->range);
	if (IS_ERR(pin_range->pctldev)) {
		ret = PTR_ERR(pin_range->pctldev);
		pr_err("%s: GPIO chip: could not create pin range\n",
		       chip->label);
		kfree(pin_range);
		return ret;
	}
	pr_debug("GPIO chip %s: created GPIO range %d->%d ==> %s PIN %d->%d\n",
		 chip->label, gpio_offset, gpio_offset + npins - 1,
		 pinctl_name,
		 pin_offset, pin_offset + npins - 1);

	list_add_tail(&pin_range->node, &chip->pin_ranges);

	return 0;
}
EXPORT_SYMBOL_GPL(gpiochip_add_pin_range);

/**
 * gpiochip_remove_pin_ranges() - remove all the GPIO <-> pin mappings
 * @chip: the chip to remove all the mappings for
 */
void gpiochip_remove_pin_ranges(struct gpio_chip *chip)
{
	struct gpio_pin_range *pin_range, *tmp;

	list_for_each_entry_safe(pin_range, tmp, &chip->pin_ranges, node) {
		list_del(&pin_range->node);
		pinctrl_remove_gpio_range(pin_range->pctldev,
				&pin_range->range);
		kfree(pin_range);
	}
}
EXPORT_SYMBOL_GPL(gpiochip_remove_pin_ranges);

#endif /* CONFIG_PINCTRL */

/* These "optional" allocation calls help prevent drivers from stomping
 * on each other, and help provide better diagnostics in debugfs.
 * They're called even less than the "set direction" calls.
 */
static int gpiod_request(struct gpio_desc *desc, const char *label)
{
	struct gpio_chip	*chip;
	int			status = -EPROBE_DEFER;
	unsigned long		flags;

	if (!desc) {
		pr_warn("%s: invalid GPIO\n", __func__);
		return -EINVAL;
	}

	spin_lock_irqsave(&gpio_lock, flags);

	chip = desc->chip;
	if (chip == NULL)
		goto done;

	if (!try_module_get(chip->owner))
		goto done;

	/* NOTE:  gpio_request() can be called in early boot,
	 * before IRQs are enabled, for non-sleeping (SOC) GPIOs.
	 */

	if (test_and_set_bit(FLAG_REQUESTED, &desc->flags) == 0) {
		desc_set_label(desc, label ? : "?");
		status = 0;
	} else {
		status = -EBUSY;
		module_put(chip->owner);
		goto done;
	}

	if (chip->request) {
		/* chip->request may sleep */
		spin_unlock_irqrestore(&gpio_lock, flags);
		status = chip->request(chip, gpio_chip_hwgpio(desc));
		spin_lock_irqsave(&gpio_lock, flags);

		if (status < 0) {
			desc_set_label(desc, NULL);
			module_put(chip->owner);
			clear_bit(FLAG_REQUESTED, &desc->flags);
			goto done;
		}
	}
	if (chip->get_direction) {
		/* chip->get_direction may sleep */
		spin_unlock_irqrestore(&gpio_lock, flags);
		gpiod_get_direction(desc);
		spin_lock_irqsave(&gpio_lock, flags);
	}
done:
	if (status)
		pr_debug("_gpio_request: gpio-%d (%s) status %d\n",
			 desc_to_gpio(desc), label ? : "?", status);
	spin_unlock_irqrestore(&gpio_lock, flags);
	return status;
}

int gpio_request(unsigned gpio, const char *label)
{
	return gpiod_request(gpio_to_desc(gpio), label);
}
EXPORT_SYMBOL_GPL(gpio_request);

static void gpiod_free(struct gpio_desc *desc)
{
	unsigned long		flags;
	struct gpio_chip	*chip;

	might_sleep();

	if (!desc) {
		WARN_ON(extra_checks);
		return;
	}

	gpiod_unexport(desc);

	spin_lock_irqsave(&gpio_lock, flags);

	chip = desc->chip;
	if (chip && test_bit(FLAG_REQUESTED, &desc->flags)) {
		if (chip->free) {
			spin_unlock_irqrestore(&gpio_lock, flags);
			might_sleep_if(chip->can_sleep);
			chip->free(chip, gpio_chip_hwgpio(desc));
			spin_lock_irqsave(&gpio_lock, flags);
		}
		desc_set_label(desc, NULL);
		module_put(desc->chip->owner);
		clear_bit(FLAG_ACTIVE_LOW, &desc->flags);
		clear_bit(FLAG_REQUESTED, &desc->flags);
		clear_bit(FLAG_OPEN_DRAIN, &desc->flags);
		clear_bit(FLAG_OPEN_SOURCE, &desc->flags);
	} else
		WARN_ON(extra_checks);

	spin_unlock_irqrestore(&gpio_lock, flags);
}

void gpio_free(unsigned gpio)
{
	gpiod_free(gpio_to_desc(gpio));
}
EXPORT_SYMBOL_GPL(gpio_free);

/**
 * gpio_request_one - request a single GPIO with initial configuration
 * @gpio:	the GPIO number
 * @flags:	GPIO configuration as specified by GPIOF_*
 * @label:	a literal description string of this GPIO
 */
int gpio_request_one(unsigned gpio, unsigned long flags, const char *label)
{
	struct gpio_desc *desc;
	int err;

	desc = gpio_to_desc(gpio);

	err = gpiod_request(desc, label);
	if (err)
		return err;

	if (flags & GPIOF_OPEN_DRAIN)
		set_bit(FLAG_OPEN_DRAIN, &desc->flags);

	if (flags & GPIOF_OPEN_SOURCE)
		set_bit(FLAG_OPEN_SOURCE, &desc->flags);

	if (flags & GPIOF_DIR_IN)
		err = gpiod_direction_input(desc);
	else
		err = gpiod_direction_output(desc,
				(flags & GPIOF_INIT_HIGH) ? 1 : 0);

	if (err)
		goto free_gpio;

	if (flags & GPIOF_EXPORT) {
		err = gpiod_export(desc, flags & GPIOF_EXPORT_CHANGEABLE);
		if (err)
			goto free_gpio;
	}

	return 0;

 free_gpio:
	gpiod_free(desc);
	return err;
}
EXPORT_SYMBOL_GPL(gpio_request_one);

/**
 * gpio_request_array - request multiple GPIOs in a single call
 * @array:	array of the 'struct gpio'
 * @num:	how many GPIOs in the array
 */
int gpio_request_array(const struct gpio *array, size_t num)
{
	int i, err;

	for (i = 0; i < num; i++, array++) {
		err = gpio_request_one(array->gpio, array->flags, array->label);
		if (err)
			goto err_free;
	}
	return 0;

err_free:
	while (i--)
		gpio_free((--array)->gpio);
	return err;
}
EXPORT_SYMBOL_GPL(gpio_request_array);

/**
 * gpio_free_array - release multiple GPIOs in a single call
 * @array:	array of the 'struct gpio'
 * @num:	how many GPIOs in the array
 */
void gpio_free_array(const struct gpio *array, size_t num)
{
	while (num--)
		gpio_free((array++)->gpio);
}
EXPORT_SYMBOL_GPL(gpio_free_array);

/**
 * gpiochip_is_requested - return string iff signal was requested
 * @chip: controller managing the signal
 * @offset: of signal within controller's 0..(ngpio - 1) range
 *
 * Returns NULL if the GPIO is not currently requested, else a string.
 * If debugfs support is enabled, the string returned is the label passed
 * to gpio_request(); otherwise it is a meaningless constant.
 *
 * This function is for use by GPIO controller drivers.  The label can
 * help with diagnostics, and knowing that the signal is used as a GPIO
 * can help avoid accidentally multiplexing it to another controller.
 */
const char *gpiochip_is_requested(struct gpio_chip *chip, unsigned offset)
{
	struct gpio_desc *desc;

	if (!GPIO_OFFSET_VALID(chip, offset))
		return NULL;

	desc = &chip->desc[offset];

	if (test_bit(FLAG_REQUESTED, &desc->flags) == 0)
		return NULL;
#ifdef CONFIG_DEBUG_FS
	return desc->label;
#else
	return "?";
#endif
}
EXPORT_SYMBOL_GPL(gpiochip_is_requested);


/* Drivers MUST set GPIO direction before making get/set calls.  In
 * some cases this is done in early boot, before IRQs are enabled.
 *
 * As a rule these aren't called more than once (except for drivers
 * using the open-drain emulation idiom) so these are natural places
 * to accumulate extra debugging checks.  Note that we can't (yet)
 * rely on gpio_request() having been called beforehand.
 */

/**
 * gpiod_direction_input - set the GPIO direction to input
 * @desc:	GPIO to set to input
 *
 * Set the direction of the passed GPIO to input, such as gpiod_get_value() can
 * be called safely on it.
 *
 * Return 0 in case of success, else an error code.
 */
int gpiod_direction_input(struct gpio_desc *desc)
{
	unsigned long		flags;
	struct gpio_chip	*chip;
	int			status = -EINVAL;
	int			offset;

	if (!desc || !desc->chip) {
		pr_warn("%s: invalid GPIO\n", __func__);
		return -EINVAL;
	}

	chip = desc->chip;
	if (!chip->get || !chip->direction_input) {
		gpiod_warn(desc,
			"%s: missing get() or direction_input() operations\n",
			 __func__);
		return -EIO;
	}

	spin_lock_irqsave(&gpio_lock, flags);

	status = gpio_ensure_requested(desc);
	if (status < 0)
		goto fail;

	/* now we know the gpio is valid and chip won't vanish */

	spin_unlock_irqrestore(&gpio_lock, flags);

	might_sleep_if(chip->can_sleep);

	offset = gpio_chip_hwgpio(desc);
	if (status) {
		status = chip->request(chip, offset);
		if (status < 0) {
			gpiod_dbg(desc, "chip request fail, %d\n", status);
			/* and it's not available to anyone else ...
			 * gpio_request() is the fully clean solution.
			 */
			goto lose;
		}
	}

	status = chip->direction_input(chip, offset);
	if (status == 0)
		clear_bit(FLAG_IS_OUT, &desc->flags);

	trace_gpio_direction(desc_to_gpio(desc), 1, status);
lose:
	return status;
fail:
	spin_unlock_irqrestore(&gpio_lock, flags);
	if (status)
		gpiod_dbg(desc, "%s status %d\n", __func__, status);
	return status;
}
EXPORT_SYMBOL_GPL(gpiod_direction_input);

/**
 * gpiod_direction_output - set the GPIO direction to input
 * @desc:	GPIO to set to output
 * @value:	initial output value of the GPIO
 *
 * Set the direction of the passed GPIO to output, such as gpiod_set_value() can
 * be called safely on it. The initial value of the output must be specified.
 *
 * Return 0 in case of success, else an error code.
 */
int gpiod_direction_output(struct gpio_desc *desc, int value)
{
	unsigned long		flags;
	struct gpio_chip	*chip;
	int			status = -EINVAL;
	int offset;

	if (!desc || !desc->chip) {
		pr_warn("%s: invalid GPIO\n", __func__);
		return -EINVAL;
	}

	/* GPIOs used for IRQs shall not be set as output */
	if (test_bit(FLAG_USED_AS_IRQ, &desc->flags)) {
		gpiod_err(desc,
			  "%s: tried to set a GPIO tied to an IRQ as output\n",
			  __func__);
		return -EIO;
	}

	/* Open drain pin should not be driven to 1 */
	if (value && test_bit(FLAG_OPEN_DRAIN,  &desc->flags))
		return gpiod_direction_input(desc);

	/* Open source pin should not be driven to 0 */
	if (!value && test_bit(FLAG_OPEN_SOURCE,  &desc->flags))
		return gpiod_direction_input(desc);

	chip = desc->chip;
	if (!chip->set || !chip->direction_output) {
		gpiod_warn(desc,
		       "%s: missing set() or direction_output() operations\n",
		       __func__);
		return -EIO;
	}

	spin_lock_irqsave(&gpio_lock, flags);

	status = gpio_ensure_requested(desc);
	if (status < 0)
		goto fail;

	/* now we know the gpio is valid and chip won't vanish */

	spin_unlock_irqrestore(&gpio_lock, flags);

	might_sleep_if(chip->can_sleep);

	offset = gpio_chip_hwgpio(desc);
	if (status) {
		status = chip->request(chip, offset);
		if (status < 0) {
			gpiod_dbg(desc, "chip request fail, %d\n", status);
			/* and it's not available to anyone else ...
			 * gpio_request() is the fully clean solution.
			 */
			goto lose;
		}
	}

	status = chip->direction_output(chip, offset, value);
	if (status == 0)
		set_bit(FLAG_IS_OUT, &desc->flags);
	trace_gpio_value(desc_to_gpio(desc), 0, value);
	trace_gpio_direction(desc_to_gpio(desc), 0, status);
lose:
	return status;
fail:
	spin_unlock_irqrestore(&gpio_lock, flags);
	if (status)
		gpiod_dbg(desc, "%s: gpio status %d\n", __func__, status);
	return status;
}
EXPORT_SYMBOL_GPL(gpiod_direction_output);

/**
 * gpiod_set_debounce - sets @debounce time for a @gpio
 * @gpio: the gpio to set debounce time
 * @debounce: debounce time is microseconds
 *
 * returns -ENOTSUPP if the controller does not support setting
 * debounce.
 */
int gpiod_set_debounce(struct gpio_desc *desc, unsigned debounce)
{
	unsigned long		flags;
	struct gpio_chip	*chip;
	int			status = -EINVAL;
	int			offset;

	if (!desc || !desc->chip) {
		pr_warn("%s: invalid GPIO\n", __func__);
		return -EINVAL;
	}

	chip = desc->chip;
	if (!chip->set || !chip->set_debounce) {
		gpiod_dbg(desc,
			  "%s: missing set() or set_debounce() operations\n",
			  __func__);
		return -ENOTSUPP;
	}

	spin_lock_irqsave(&gpio_lock, flags);

	status = gpio_ensure_requested(desc);
	if (status < 0)
		goto fail;

	/* now we know the gpio is valid and chip won't vanish */

	spin_unlock_irqrestore(&gpio_lock, flags);

	might_sleep_if(chip->can_sleep);

	offset = gpio_chip_hwgpio(desc);
	return chip->set_debounce(chip, offset, debounce);

fail:
	spin_unlock_irqrestore(&gpio_lock, flags);
	if (status)
		gpiod_dbg(desc, "%s: status %d\n", __func__, status);

	return status;
}
EXPORT_SYMBOL_GPL(gpiod_set_debounce);

/**
 * gpiod_is_active_low - test whether a GPIO is active-low or not
 * @desc: the gpio descriptor to test
 *
 * Returns 1 if the GPIO is active-low, 0 otherwise.
 */
int gpiod_is_active_low(const struct gpio_desc *desc)
{
	return test_bit(FLAG_ACTIVE_LOW, &desc->flags);
}
EXPORT_SYMBOL_GPL(gpiod_is_active_low);

/* I/O calls are only valid after configuration completed; the relevant
 * "is this a valid GPIO" error checks should already have been done.
 *
 * "Get" operations are often inlinable as reading a pin value register,
 * and masking the relevant bit in that register.
 *
 * When "set" operations are inlinable, they involve writing that mask to
 * one register to set a low value, or a different register to set it high.
 * Otherwise locking is needed, so there may be little value to inlining.
 *
 *------------------------------------------------------------------------
 *
 * IMPORTANT!!!  The hot paths -- get/set value -- assume that callers
 * have requested the GPIO.  That can include implicit requesting by
 * a direction setting call.  Marking a gpio as requested locks its chip
 * in memory, guaranteeing that these table lookups need no more locking
 * and that gpiochip_remove() will fail.
 *
 * REVISIT when debugging, consider adding some instrumentation to ensure
 * that the GPIO was actually requested.
 */

static int _gpiod_get_raw_value(const struct gpio_desc *desc)
{
	struct gpio_chip	*chip;
	int value;
	int offset;

	chip = desc->chip;
	offset = gpio_chip_hwgpio(desc);
	value = chip->get ? chip->get(chip, offset) : 0;
	trace_gpio_value(desc_to_gpio(desc), 1, value);
	return value;
}

/**
 * gpiod_get_raw_value() - return a gpio's raw value
 * @desc: gpio whose value will be returned
 *
 * Return the GPIO's raw value, i.e. the value of the physical line disregarding
 * its ACTIVE_LOW status.
 *
 * This function should be called from contexts where we cannot sleep, and will
 * complain if the GPIO chip functions potentially sleep.
 */
int gpiod_get_raw_value(const struct gpio_desc *desc)
{
	if (!desc)
		return 0;
	/* Should be using gpio_get_value_cansleep() */
	WARN_ON(desc->chip->can_sleep);
	return _gpiod_get_raw_value(desc);
}
EXPORT_SYMBOL_GPL(gpiod_get_raw_value);

/**
 * gpiod_get_value() - return a gpio's value
 * @desc: gpio whose value will be returned
 *
 * Return the GPIO's logical value, i.e. taking the ACTIVE_LOW status into
 * account.
 *
 * This function should be called from contexts where we cannot sleep, and will
 * complain if the GPIO chip functions potentially sleep.
 */
int gpiod_get_value(const struct gpio_desc *desc)
{
	int value;
	if (!desc)
		return 0;
	/* Should be using gpio_get_value_cansleep() */
	WARN_ON(desc->chip->can_sleep);

	value = _gpiod_get_raw_value(desc);
	if (test_bit(FLAG_ACTIVE_LOW, &desc->flags))
		value = !value;

	return value;
}
EXPORT_SYMBOL_GPL(gpiod_get_value);

/*
 *  _gpio_set_open_drain_value() - Set the open drain gpio's value.
 * @desc: gpio descriptor whose state need to be set.
 * @value: Non-zero for setting it HIGH otherise it will set to LOW.
 */
static void _gpio_set_open_drain_value(struct gpio_desc *desc, int value)
{
	int err = 0;
	struct gpio_chip *chip = desc->chip;
	int offset = gpio_chip_hwgpio(desc);

	if (value) {
		err = chip->direction_input(chip, offset);
		if (!err)
			clear_bit(FLAG_IS_OUT, &desc->flags);
	} else {
		err = chip->direction_output(chip, offset, 0);
		if (!err)
			set_bit(FLAG_IS_OUT, &desc->flags);
	}
	trace_gpio_direction(desc_to_gpio(desc), value, err);
	if (err < 0)
		gpiod_err(desc,
			  "%s: Error in set_value for open drain err %d\n",
			  __func__, err);
}

/*
 *  _gpio_set_open_source_value() - Set the open source gpio's value.
 * @desc: gpio descriptor whose state need to be set.
 * @value: Non-zero for setting it HIGH otherise it will set to LOW.
 */
static void _gpio_set_open_source_value(struct gpio_desc *desc, int value)
{
	int err = 0;
	struct gpio_chip *chip = desc->chip;
	int offset = gpio_chip_hwgpio(desc);

	if (value) {
		err = chip->direction_output(chip, offset, 1);
		if (!err)
			set_bit(FLAG_IS_OUT, &desc->flags);
	} else {
		err = chip->direction_input(chip, offset);
		if (!err)
			clear_bit(FLAG_IS_OUT, &desc->flags);
	}
	trace_gpio_direction(desc_to_gpio(desc), !value, err);
	if (err < 0)
		gpiod_err(desc,
			  "%s: Error in set_value for open source err %d\n",
			  __func__, err);
}

static void _gpiod_set_raw_value(struct gpio_desc *desc, int value)
{
	struct gpio_chip	*chip;

	chip = desc->chip;
	trace_gpio_value(desc_to_gpio(desc), 0, value);
	if (test_bit(FLAG_OPEN_DRAIN, &desc->flags))
		_gpio_set_open_drain_value(desc, value);
	else if (test_bit(FLAG_OPEN_SOURCE, &desc->flags))
		_gpio_set_open_source_value(desc, value);
	else
		chip->set(chip, gpio_chip_hwgpio(desc), value);
}

/**
 * gpiod_set_raw_value() - assign a gpio's raw value
 * @desc: gpio whose value will be assigned
 * @value: value to assign
 *
 * Set the raw value of the GPIO, i.e. the value of its physical line without
 * regard for its ACTIVE_LOW status.
 *
 * This function should be called from contexts where we cannot sleep, and will
 * complain if the GPIO chip functions potentially sleep.
 */
void gpiod_set_raw_value(struct gpio_desc *desc, int value)
{
	if (!desc)
		return;
	/* Should be using gpio_set_value_cansleep() */
	WARN_ON(desc->chip->can_sleep);
	_gpiod_set_raw_value(desc, value);
}
EXPORT_SYMBOL_GPL(gpiod_set_raw_value);

/**
 * gpiod_set_value() - assign a gpio's value
 * @desc: gpio whose value will be assigned
 * @value: value to assign
 *
 * Set the logical value of the GPIO, i.e. taking its ACTIVE_LOW status into
 * account
 *
 * This function should be called from contexts where we cannot sleep, and will
 * complain if the GPIO chip functions potentially sleep.
 */
void gpiod_set_value(struct gpio_desc *desc, int value)
{
	if (!desc)
		return;
	/* Should be using gpio_set_value_cansleep() */
	WARN_ON(desc->chip->can_sleep);
	if (test_bit(FLAG_ACTIVE_LOW, &desc->flags))
		value = !value;
	_gpiod_set_raw_value(desc, value);
}
EXPORT_SYMBOL_GPL(gpiod_set_value);

/**
 * gpiod_cansleep() - report whether gpio value access may sleep
 * @desc: gpio to check
 *
 */
int gpiod_cansleep(const struct gpio_desc *desc)
{
	if (!desc)
		return 0;
	return desc->chip->can_sleep;
}
EXPORT_SYMBOL_GPL(gpiod_cansleep);

/**
 * gpiod_to_irq() - return the IRQ corresponding to a GPIO
 * @desc: gpio whose IRQ will be returned (already requested)
 *
 * Return the IRQ corresponding to the passed GPIO, or an error code in case of
 * error.
 */
int gpiod_to_irq(const struct gpio_desc *desc)
{
	struct gpio_chip	*chip;
	int			offset;

	if (!desc)
		return -EINVAL;
	chip = desc->chip;
	offset = gpio_chip_hwgpio(desc);
	return chip->to_irq ? chip->to_irq(chip, offset) : -ENXIO;
}
EXPORT_SYMBOL_GPL(gpiod_to_irq);

/**
 * gpiod_lock_as_irq() - lock a GPIO to be used as IRQ
 * @gpio: the GPIO line to lock as used for IRQ
 *
 * This is used directly by GPIO drivers that want to lock down
 * a certain GPIO line to be used as IRQs, for example in the
 * .to_irq() callback of their gpio_chip, or in the .irq_enable()
 * of its irq_chip implementation if the GPIO is known from that
 * code.
 */
int gpiod_lock_as_irq(struct gpio_desc *desc)
{
	if (!desc)
		return -EINVAL;

	if (test_bit(FLAG_IS_OUT, &desc->flags)) {
		gpiod_err(desc,
			  "%s: tried to flag a GPIO set as output for IRQ\n",
			  __func__);
		return -EIO;
	}

	set_bit(FLAG_USED_AS_IRQ, &desc->flags);
	return 0;
}
EXPORT_SYMBOL_GPL(gpiod_lock_as_irq);

int gpio_lock_as_irq(struct gpio_chip *chip, unsigned int offset)
{
	return gpiod_lock_as_irq(gpiochip_offset_to_desc(chip, offset));
}
EXPORT_SYMBOL_GPL(gpio_lock_as_irq);

/**
 * gpiod_unlock_as_irq() - unlock a GPIO used as IRQ
 * @gpio: the GPIO line to unlock from IRQ usage
 *
 * This is used directly by GPIO drivers that want to indicate
 * that a certain GPIO is no longer used exclusively for IRQ.
 */
void gpiod_unlock_as_irq(struct gpio_desc *desc)
{
	if (!desc)
		return;

	clear_bit(FLAG_USED_AS_IRQ, &desc->flags);
}
EXPORT_SYMBOL_GPL(gpiod_unlock_as_irq);

void gpio_unlock_as_irq(struct gpio_chip *chip, unsigned int offset)
{
	return gpiod_unlock_as_irq(gpiochip_offset_to_desc(chip, offset));
}
EXPORT_SYMBOL_GPL(gpio_unlock_as_irq);

/**
 * gpiod_get_raw_value_cansleep() - return a gpio's raw value
 * @desc: gpio whose value will be returned
 *
 * Return the GPIO's raw value, i.e. the value of the physical line disregarding
 * its ACTIVE_LOW status.
 *
 * This function is to be called from contexts that can sleep.
 */
int gpiod_get_raw_value_cansleep(const struct gpio_desc *desc)
{
	might_sleep_if(extra_checks);
	if (!desc)
		return 0;
	return _gpiod_get_raw_value(desc);
}
EXPORT_SYMBOL_GPL(gpiod_get_raw_value_cansleep);

/**
 * gpiod_get_value_cansleep() - return a gpio's value
 * @desc: gpio whose value will be returned
 *
 * Return the GPIO's logical value, i.e. taking the ACTIVE_LOW status into
 * account.
 *
 * This function is to be called from contexts that can sleep.
 */
int gpiod_get_value_cansleep(const struct gpio_desc *desc)
{
	int value;

	might_sleep_if(extra_checks);
	if (!desc)
		return 0;

	value = _gpiod_get_raw_value(desc);
	if (test_bit(FLAG_ACTIVE_LOW, &desc->flags))
		value = !value;

	return value;
}
EXPORT_SYMBOL_GPL(gpiod_get_value_cansleep);

/**
 * gpiod_set_raw_value_cansleep() - assign a gpio's raw value
 * @desc: gpio whose value will be assigned
 * @value: value to assign
 *
 * Set the raw value of the GPIO, i.e. the value of its physical line without
 * regard for its ACTIVE_LOW status.
 *
 * This function is to be called from contexts that can sleep.
 */
void gpiod_set_raw_value_cansleep(struct gpio_desc *desc, int value)
{
	might_sleep_if(extra_checks);
	if (!desc)
		return;
	_gpiod_set_raw_value(desc, value);
}
EXPORT_SYMBOL_GPL(gpiod_set_raw_value_cansleep);

/**
 * gpiod_set_value_cansleep() - assign a gpio's value
 * @desc: gpio whose value will be assigned
 * @value: value to assign
 *
 * Set the logical value of the GPIO, i.e. taking its ACTIVE_LOW status into
 * account
 *
 * This function is to be called from contexts that can sleep.
 */
void gpiod_set_value_cansleep(struct gpio_desc *desc, int value)
{
	might_sleep_if(extra_checks);
	if (!desc)
		return;

	if (test_bit(FLAG_ACTIVE_LOW, &desc->flags))
		value = !value;
	_gpiod_set_raw_value(desc, value);
}
EXPORT_SYMBOL_GPL(gpiod_set_value_cansleep);

/**
 * gpiod_add_table() - register GPIO device consumers
 * @table: array of consumers to register
 * @num: number of consumers in table
 */
void gpiod_add_table(struct gpiod_lookup *table, size_t size)
{
	mutex_lock(&gpio_lookup_lock);

	while (size--) {
		list_add_tail(&table->list, &gpio_lookup_list);
		table++;
	}

	mutex_unlock(&gpio_lookup_lock);
}

#ifdef CONFIG_OF
static struct gpio_desc *of_find_gpio(struct device *dev, const char *con_id,
				      unsigned int idx,
				      enum gpio_lookup_flags *flags)
{
	char prop_name[32]; /* 32 is max size of property name */
	enum of_gpio_flags of_flags;
	struct gpio_desc *desc;

	if (con_id)
		snprintf(prop_name, 32, "%s-gpios", con_id);
	else
		snprintf(prop_name, 32, "gpios");

	desc = of_get_named_gpiod_flags(dev->of_node, prop_name, idx,
					&of_flags);

	if (IS_ERR(desc))
		return desc;

	if (of_flags & OF_GPIO_ACTIVE_LOW)
		*flags |= GPIO_ACTIVE_LOW;

	return desc;
}
#else
static struct gpio_desc *of_find_gpio(struct device *dev, const char *con_id,
				      unsigned int idx,
				      enum gpio_lookup_flags *flags)
{
	return ERR_PTR(-ENODEV);
}
#endif

static struct gpio_desc *acpi_find_gpio(struct device *dev, const char *con_id,
					unsigned int idx,
					enum gpio_lookup_flags *flags)
{
	struct acpi_gpio_info info;
	struct gpio_desc *desc;

	desc = acpi_get_gpiod_by_index(dev, idx, &info);
	if (IS_ERR(desc))
		return desc;

	if (info.gpioint && info.active_low)
		*flags |= GPIO_ACTIVE_LOW;

	return desc;
}

static struct gpio_desc *gpiod_find(struct device *dev, const char *con_id,
				    unsigned int idx,
				    enum gpio_lookup_flags *flags)
{
	const char *dev_id = dev ? dev_name(dev) : NULL;
	struct gpio_desc *desc = ERR_PTR(-ENODEV);
	unsigned int match, best = 0;
	struct gpiod_lookup *p;

	mutex_lock(&gpio_lookup_lock);

	list_for_each_entry(p, &gpio_lookup_list, list) {
		match = 0;

		if (p->dev_id) {
			if (!dev_id || strcmp(p->dev_id, dev_id))
				continue;

			match += 2;
		}

		if (p->con_id) {
			if (!con_id || strcmp(p->con_id, con_id))
				continue;

			match += 1;
		}

		if (p->idx != idx)
			continue;

		if (match > best) {
			struct gpio_chip *chip;

			chip = find_chip_by_name(p->chip_label);

			if (!chip) {
				dev_warn(dev, "cannot find GPIO chip %s\n",
					 p->chip_label);
				continue;
			}

			if (chip->ngpio <= p->chip_hwnum) {
				dev_warn(dev, "GPIO chip %s has %d GPIOs\n",
					 chip->label, chip->ngpio);
				continue;
			}

			desc = gpio_to_desc(chip->base + p->chip_hwnum);
			*flags = p->flags;

			if (match != 3)
				best = match;
			else
				break;
		}
	}

	mutex_unlock(&gpio_lookup_lock);

	return desc;
}

/**
 * gpio_get - obtain a GPIO for a given GPIO function
 * @dev:	GPIO consumer
 * @con_id:	function within the GPIO consumer
 *
 * Return the GPIO descriptor corresponding to the function con_id of device
 * dev, or an IS_ERR() condition if an error occured.
 */
struct gpio_desc *__must_check gpiod_get(struct device *dev, const char *con_id)
{
	return gpiod_get_index(dev, con_id, 0);
}
EXPORT_SYMBOL_GPL(gpiod_get);

/**
 * gpiod_get_index - obtain a GPIO from a multi-index GPIO function
 * @dev:	GPIO consumer
 * @con_id:	function within the GPIO consumer
 * @idx:	index of the GPIO to obtain in the consumer
 *
 * This variant of gpiod_get() allows to access GPIOs other than the first
 * defined one for functions that define several GPIOs.
 *
 * Return a valid GPIO descriptor, or an IS_ERR() condition in case of error.
 */
struct gpio_desc *__must_check gpiod_get_index(struct device *dev,
					       const char *con_id,
					       unsigned int idx)
{
	struct gpio_desc *desc;
	int status;
	enum gpio_lookup_flags flags = 0;

	dev_dbg(dev, "GPIO lookup for consumer %s\n", con_id);

	/* Using device tree? */
	if (IS_ENABLED(CONFIG_OF) && dev && dev->of_node) {
		dev_dbg(dev, "using device tree for GPIO lookup\n");
		desc = of_find_gpio(dev, con_id, idx, &flags);
	} else if (IS_ENABLED(CONFIG_ACPI) && dev && ACPI_HANDLE(dev)) {
		dev_dbg(dev, "using ACPI for GPIO lookup\n");
		desc = acpi_find_gpio(dev, con_id, idx, &flags);
	} else {
		dev_dbg(dev, "using lookup tables for GPIO lookup");
		desc = gpiod_find(dev, con_id, idx, &flags);
	}

	if (IS_ERR(desc)) {
		dev_warn(dev, "lookup for GPIO %s failed\n", con_id);
		return desc;
	}

	status = gpiod_request(desc, con_id);

	if (status < 0)
		return ERR_PTR(status);

	if (flags & GPIO_ACTIVE_LOW)
		set_bit(FLAG_ACTIVE_LOW, &desc->flags);
	if (flags & GPIO_OPEN_DRAIN)
		set_bit(FLAG_OPEN_DRAIN, &desc->flags);
	if (flags & GPIO_OPEN_SOURCE)
		set_bit(FLAG_OPEN_SOURCE, &desc->flags);

	return desc;
}
EXPORT_SYMBOL_GPL(gpiod_get_index);

/**
 * gpiod_put - dispose of a GPIO descriptor
 * @desc:	GPIO descriptor to dispose of
 *
 * No descriptor can be used after gpiod_put() has been called on it.
 */
void gpiod_put(struct gpio_desc *desc)
{
	gpiod_free(desc);
}
EXPORT_SYMBOL_GPL(gpiod_put);

#ifdef CONFIG_DEBUG_FS

static void gpiolib_dbg_show(struct seq_file *s, struct gpio_chip *chip)
{
	unsigned		i;
	unsigned		gpio = chip->base;
	struct gpio_desc	*gdesc = &chip->desc[0];
	int			is_out;
	int			is_irq;

	for (i = 0; i < chip->ngpio; i++, gpio++, gdesc++) {
		if (!test_bit(FLAG_REQUESTED, &gdesc->flags))
			continue;

		gpiod_get_direction(gdesc);
		is_out = test_bit(FLAG_IS_OUT, &gdesc->flags);
		is_irq = test_bit(FLAG_USED_AS_IRQ, &gdesc->flags);
		seq_printf(s, " gpio-%-3d (%-20.20s) %s %s %s",
			gpio, gdesc->label,
			is_out ? "out" : "in ",
			chip->get
				? (chip->get(chip, i) ? "hi" : "lo")
				: "?  ",
			is_irq ? "IRQ" : "   ");
		seq_printf(s, "\n");
	}
}

static void *gpiolib_seq_start(struct seq_file *s, loff_t *pos)
{
	unsigned long flags;
	struct gpio_chip *chip = NULL;
	loff_t index = *pos;

	s->private = "";

	spin_lock_irqsave(&gpio_lock, flags);
	list_for_each_entry(chip, &gpio_chips, list)
		if (index-- == 0) {
			spin_unlock_irqrestore(&gpio_lock, flags);
			return chip;
		}
	spin_unlock_irqrestore(&gpio_lock, flags);

	return NULL;
}

static void *gpiolib_seq_next(struct seq_file *s, void *v, loff_t *pos)
{
	unsigned long flags;
	struct gpio_chip *chip = v;
	void *ret = NULL;

	spin_lock_irqsave(&gpio_lock, flags);
	if (list_is_last(&chip->list, &gpio_chips))
		ret = NULL;
	else
		ret = list_entry(chip->list.next, struct gpio_chip, list);
	spin_unlock_irqrestore(&gpio_lock, flags);

	s->private = "\n";
	++*pos;

	return ret;
}

static void gpiolib_seq_stop(struct seq_file *s, void *v)
{
}

static int gpiolib_seq_show(struct seq_file *s, void *v)
{
	struct gpio_chip *chip = v;
	struct device *dev;

	seq_printf(s, "%sGPIOs %d-%d", (char *)s->private,
			chip->base, chip->base + chip->ngpio - 1);
	dev = chip->dev;
	if (dev)
		seq_printf(s, ", %s/%s", dev->bus ? dev->bus->name : "no-bus",
			dev_name(dev));
	if (chip->label)
		seq_printf(s, ", %s", chip->label);
	if (chip->can_sleep)
		seq_printf(s, ", can sleep");
	seq_printf(s, ":\n");

	if (chip->dbg_show)
		chip->dbg_show(s, chip);
	else
		gpiolib_dbg_show(s, chip);

	return 0;
}

static const struct seq_operations gpiolib_seq_ops = {
	.start = gpiolib_seq_start,
	.next = gpiolib_seq_next,
	.stop = gpiolib_seq_stop,
	.show = gpiolib_seq_show,
};

static int gpiolib_open(struct inode *inode, struct file *file)
{
	return seq_open(file, &gpiolib_seq_ops);
}

static const struct file_operations gpiolib_operations = {
	.owner		= THIS_MODULE,
	.open		= gpiolib_open,
	.read		= seq_read,
	.llseek		= seq_lseek,
	.release	= seq_release,
};

static int __init gpiolib_debugfs_init(void)
{
	/* /sys/kernel/debug/gpio */
	(void) debugfs_create_file("gpio", S_IFREG | S_IRUGO,
				NULL, NULL, &gpiolib_operations);
	return 0;
}
subsys_initcall(gpiolib_debugfs_init);

#endif	/* DEBUG_FS */