summaryrefslogtreecommitdiff
path: root/drivers/gpio/gpiolib-cdev.c
blob: 9dad67ea25974ea4c2dd68d267d728af7603f2bc (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
2597
2598
2599
2600
2601
2602
2603
2604
2605
2606
2607
2608
2609
2610
2611
2612
2613
2614
2615
2616
2617
2618
2619
2620
2621
2622
2623
2624
2625
2626
2627
2628
2629
2630
2631
2632
2633
2634
2635
2636
2637
2638
2639
2640
2641
2642
2643
2644
2645
2646
2647
2648
2649
2650
2651
2652
2653
2654
2655
2656
2657
2658
2659
2660
2661
2662
2663
2664
2665
2666
2667
2668
2669
2670
2671
2672
2673
2674
2675
2676
2677
2678
2679
2680
2681
2682
2683
2684
2685
2686
2687
2688
2689
2690
2691
2692
2693
2694
2695
2696
2697
2698
2699
2700
2701
2702
2703
2704
2705
2706
2707
2708
2709
2710
2711
2712
2713
2714
2715
2716
2717
2718
2719
2720
2721
2722
2723
2724
2725
2726
2727
2728
2729
2730
2731
2732
2733
2734
2735
2736
2737
2738
2739
2740
2741
2742
2743
2744
2745
2746
2747
2748
2749
2750
2751
2752
2753
2754
2755
2756
2757
2758
2759
2760
2761
2762
2763
2764
2765
2766
2767
2768
2769
2770
2771
2772
2773
2774
2775
2776
2777
2778
2779
2780
2781
2782
2783
2784
2785
2786
2787
2788
2789
2790
2791
2792
2793
2794
2795
2796
2797
2798
2799
2800
2801
2802
2803
2804
2805
2806
2807
2808
2809
2810
2811
2812
2813
2814
2815
2816
2817
2818
2819
2820
2821
2822
2823
2824
2825
2826
2827
2828
2829
2830
2831
2832
2833
2834
2835
2836
2837
2838
2839
2840
2841
2842
2843
2844
2845
2846
2847
2848
2849
2850
2851
2852
2853
2854
2855
2856
2857
2858
2859
2860
2861
2862
2863
2864
2865
2866
2867
// SPDX-License-Identifier: GPL-2.0

#include <linux/anon_inodes.h>
#include <linux/atomic.h>
#include <linux/bitmap.h>
#include <linux/build_bug.h>
#include <linux/cdev.h>
#include <linux/cleanup.h>
#include <linux/compat.h>
#include <linux/compiler.h>
#include <linux/device.h>
#include <linux/err.h>
#include <linux/file.h>
#include <linux/gpio.h>
#include <linux/gpio/driver.h>
#include <linux/hte.h>
#include <linux/interrupt.h>
#include <linux/irqreturn.h>
#include <linux/kernel.h>
#include <linux/kfifo.h>
#include <linux/module.h>
#include <linux/mutex.h>
#include <linux/overflow.h>
#include <linux/pinctrl/consumer.h>
#include <linux/poll.h>
#include <linux/rbtree.h>
#include <linux/seq_file.h>
#include <linux/spinlock.h>
#include <linux/timekeeping.h>
#include <linux/uaccess.h>
#include <linux/workqueue.h>

#include <uapi/linux/gpio.h>

#include "gpiolib.h"
#include "gpiolib-cdev.h"

/*
 * Array sizes must ensure 64-bit alignment and not create holes in the
 * struct packing.
 */
static_assert(IS_ALIGNED(GPIO_V2_LINES_MAX, 2));
static_assert(IS_ALIGNED(GPIO_MAX_NAME_SIZE, 8));

/*
 * Check that uAPI structs are 64-bit aligned for 32/64-bit compatibility
 */
static_assert(IS_ALIGNED(sizeof(struct gpio_v2_line_attribute), 8));
static_assert(IS_ALIGNED(sizeof(struct gpio_v2_line_config_attribute), 8));
static_assert(IS_ALIGNED(sizeof(struct gpio_v2_line_config), 8));
static_assert(IS_ALIGNED(sizeof(struct gpio_v2_line_request), 8));
static_assert(IS_ALIGNED(sizeof(struct gpio_v2_line_info), 8));
static_assert(IS_ALIGNED(sizeof(struct gpio_v2_line_info_changed), 8));
static_assert(IS_ALIGNED(sizeof(struct gpio_v2_line_event), 8));
static_assert(IS_ALIGNED(sizeof(struct gpio_v2_line_values), 8));

/* Character device interface to GPIO.
 *
 * The GPIO character device, /dev/gpiochipN, provides userspace an
 * interface to gpiolib GPIOs via ioctl()s.
 */

/*
 * GPIO line handle management
 */

#ifdef CONFIG_GPIO_CDEV_V1
/**
 * struct linehandle_state - contains the state of a userspace handle
 * @gdev: the GPIO device the handle pertains to
 * @label: consumer label used to tag descriptors
 * @descs: the GPIO descriptors held by this handle
 * @num_descs: the number of descriptors held in the descs array
 */
struct linehandle_state {
	struct gpio_device *gdev;
	const char *label;
	struct gpio_desc *descs[GPIOHANDLES_MAX];
	u32 num_descs;
};

#define GPIOHANDLE_REQUEST_VALID_FLAGS \
	(GPIOHANDLE_REQUEST_INPUT | \
	GPIOHANDLE_REQUEST_OUTPUT | \
	GPIOHANDLE_REQUEST_ACTIVE_LOW | \
	GPIOHANDLE_REQUEST_BIAS_PULL_UP | \
	GPIOHANDLE_REQUEST_BIAS_PULL_DOWN | \
	GPIOHANDLE_REQUEST_BIAS_DISABLE | \
	GPIOHANDLE_REQUEST_OPEN_DRAIN | \
	GPIOHANDLE_REQUEST_OPEN_SOURCE)

static int linehandle_validate_flags(u32 flags)
{
	/* Return an error if an unknown flag is set */
	if (flags & ~GPIOHANDLE_REQUEST_VALID_FLAGS)
		return -EINVAL;

	/*
	 * Do not allow both INPUT & OUTPUT flags to be set as they are
	 * contradictory.
	 */
	if ((flags & GPIOHANDLE_REQUEST_INPUT) &&
	    (flags & GPIOHANDLE_REQUEST_OUTPUT))
		return -EINVAL;

	/*
	 * Do not allow OPEN_SOURCE & OPEN_DRAIN flags in a single request. If
	 * the hardware actually supports enabling both at the same time the
	 * electrical result would be disastrous.
	 */
	if ((flags & GPIOHANDLE_REQUEST_OPEN_DRAIN) &&
	    (flags & GPIOHANDLE_REQUEST_OPEN_SOURCE))
		return -EINVAL;

	/* OPEN_DRAIN and OPEN_SOURCE flags only make sense for output mode. */
	if (!(flags & GPIOHANDLE_REQUEST_OUTPUT) &&
	    ((flags & GPIOHANDLE_REQUEST_OPEN_DRAIN) ||
	     (flags & GPIOHANDLE_REQUEST_OPEN_SOURCE)))
		return -EINVAL;

	/* Bias flags only allowed for input or output mode. */
	if (!((flags & GPIOHANDLE_REQUEST_INPUT) ||
	      (flags & GPIOHANDLE_REQUEST_OUTPUT)) &&
	    ((flags & GPIOHANDLE_REQUEST_BIAS_DISABLE) ||
	     (flags & GPIOHANDLE_REQUEST_BIAS_PULL_UP) ||
	     (flags & GPIOHANDLE_REQUEST_BIAS_PULL_DOWN)))
		return -EINVAL;

	/* Only one bias flag can be set. */
	if (((flags & GPIOHANDLE_REQUEST_BIAS_DISABLE) &&
	     (flags & (GPIOHANDLE_REQUEST_BIAS_PULL_DOWN |
		       GPIOHANDLE_REQUEST_BIAS_PULL_UP))) ||
	    ((flags & GPIOHANDLE_REQUEST_BIAS_PULL_DOWN) &&
	     (flags & GPIOHANDLE_REQUEST_BIAS_PULL_UP)))
		return -EINVAL;

	return 0;
}

static void linehandle_flags_to_desc_flags(u32 lflags, unsigned long *flagsp)
{
	assign_bit(FLAG_ACTIVE_LOW, flagsp,
		   lflags & GPIOHANDLE_REQUEST_ACTIVE_LOW);
	assign_bit(FLAG_OPEN_DRAIN, flagsp,
		   lflags & GPIOHANDLE_REQUEST_OPEN_DRAIN);
	assign_bit(FLAG_OPEN_SOURCE, flagsp,
		   lflags & GPIOHANDLE_REQUEST_OPEN_SOURCE);
	assign_bit(FLAG_PULL_UP, flagsp,
		   lflags & GPIOHANDLE_REQUEST_BIAS_PULL_UP);
	assign_bit(FLAG_PULL_DOWN, flagsp,
		   lflags & GPIOHANDLE_REQUEST_BIAS_PULL_DOWN);
	assign_bit(FLAG_BIAS_DISABLE, flagsp,
		   lflags & GPIOHANDLE_REQUEST_BIAS_DISABLE);
}

static long linehandle_set_config(struct linehandle_state *lh,
				  void __user *ip)
{
	struct gpiohandle_config gcnf;
	struct gpio_desc *desc;
	int i, ret;
	u32 lflags;

	if (copy_from_user(&gcnf, ip, sizeof(gcnf)))
		return -EFAULT;

	lflags = gcnf.flags;
	ret = linehandle_validate_flags(lflags);
	if (ret)
		return ret;

	for (i = 0; i < lh->num_descs; i++) {
		desc = lh->descs[i];
		linehandle_flags_to_desc_flags(gcnf.flags, &desc->flags);

		/*
		 * Lines have to be requested explicitly for input
		 * or output, else the line will be treated "as is".
		 */
		if (lflags & GPIOHANDLE_REQUEST_OUTPUT) {
			int val = !!gcnf.default_values[i];

			ret = gpiod_direction_output(desc, val);
			if (ret)
				return ret;
		} else if (lflags & GPIOHANDLE_REQUEST_INPUT) {
			ret = gpiod_direction_input(desc);
			if (ret)
				return ret;
		}

		gpiod_line_state_notify(desc, GPIO_V2_LINE_CHANGED_CONFIG);
	}
	return 0;
}

static long linehandle_ioctl(struct file *file, unsigned int cmd,
			     unsigned long arg)
{
	struct linehandle_state *lh = file->private_data;
	void __user *ip = (void __user *)arg;
	struct gpiohandle_data ghd;
	DECLARE_BITMAP(vals, GPIOHANDLES_MAX);
	unsigned int i;
	int ret;

	guard(srcu)(&lh->gdev->srcu);

	if (!rcu_access_pointer(lh->gdev->chip))
		return -ENODEV;

	switch (cmd) {
	case GPIOHANDLE_GET_LINE_VALUES_IOCTL:
		/* NOTE: It's okay to read values of output lines */
		ret = gpiod_get_array_value_complex(false, true,
						    lh->num_descs, lh->descs,
						    NULL, vals);
		if (ret)
			return ret;

		memset(&ghd, 0, sizeof(ghd));
		for (i = 0; i < lh->num_descs; i++)
			ghd.values[i] = test_bit(i, vals);

		if (copy_to_user(ip, &ghd, sizeof(ghd)))
			return -EFAULT;

		return 0;
	case GPIOHANDLE_SET_LINE_VALUES_IOCTL:
		/*
		 * All line descriptors were created at once with the same
		 * flags so just check if the first one is really output.
		 */
		if (!test_bit(FLAG_IS_OUT, &lh->descs[0]->flags))
			return -EPERM;

		if (copy_from_user(&ghd, ip, sizeof(ghd)))
			return -EFAULT;

		/* Clamp all values to [0,1] */
		for (i = 0; i < lh->num_descs; i++)
			__assign_bit(i, vals, ghd.values[i]);

		/* Reuse the array setting function */
		return gpiod_set_array_value_complex(false,
						     true,
						     lh->num_descs,
						     lh->descs,
						     NULL,
						     vals);
	case GPIOHANDLE_SET_CONFIG_IOCTL:
		return linehandle_set_config(lh, ip);
	default:
		return -EINVAL;
	}
}

#ifdef CONFIG_COMPAT
static long linehandle_ioctl_compat(struct file *file, unsigned int cmd,
				    unsigned long arg)
{
	return linehandle_ioctl(file, cmd, (unsigned long)compat_ptr(arg));
}
#endif

static void linehandle_free(struct linehandle_state *lh)
{
	int i;

	for (i = 0; i < lh->num_descs; i++)
		if (lh->descs[i])
			gpiod_free(lh->descs[i]);
	kfree(lh->label);
	gpio_device_put(lh->gdev);
	kfree(lh);
}

static int linehandle_release(struct inode *inode, struct file *file)
{
	linehandle_free(file->private_data);
	return 0;
}

static const struct file_operations linehandle_fileops = {
	.release = linehandle_release,
	.owner = THIS_MODULE,
	.llseek = noop_llseek,
	.unlocked_ioctl = linehandle_ioctl,
#ifdef CONFIG_COMPAT
	.compat_ioctl = linehandle_ioctl_compat,
#endif
};

static int linehandle_create(struct gpio_device *gdev, void __user *ip)
{
	struct gpiohandle_request handlereq;
	struct linehandle_state *lh;
	struct file *file;
	int fd, i, ret;
	u32 lflags;

	if (copy_from_user(&handlereq, ip, sizeof(handlereq)))
		return -EFAULT;
	if ((handlereq.lines == 0) || (handlereq.lines > GPIOHANDLES_MAX))
		return -EINVAL;

	lflags = handlereq.flags;

	ret = linehandle_validate_flags(lflags);
	if (ret)
		return ret;

	lh = kzalloc(sizeof(*lh), GFP_KERNEL);
	if (!lh)
		return -ENOMEM;
	lh->gdev = gpio_device_get(gdev);

	if (handlereq.consumer_label[0] != '\0') {
		/* label is only initialized if consumer_label is set */
		lh->label = kstrndup(handlereq.consumer_label,
				     sizeof(handlereq.consumer_label) - 1,
				     GFP_KERNEL);
		if (!lh->label) {
			ret = -ENOMEM;
			goto out_free_lh;
		}
	}

	lh->num_descs = handlereq.lines;

	/* Request each GPIO */
	for (i = 0; i < handlereq.lines; i++) {
		u32 offset = handlereq.lineoffsets[i];
		struct gpio_desc *desc = gpio_device_get_desc(gdev, offset);

		if (IS_ERR(desc)) {
			ret = PTR_ERR(desc);
			goto out_free_lh;
		}

		ret = gpiod_request_user(desc, lh->label);
		if (ret)
			goto out_free_lh;
		lh->descs[i] = desc;
		linehandle_flags_to_desc_flags(handlereq.flags, &desc->flags);

		ret = gpiod_set_transitory(desc, false);
		if (ret < 0)
			goto out_free_lh;

		/*
		 * Lines have to be requested explicitly for input
		 * or output, else the line will be treated "as is".
		 */
		if (lflags & GPIOHANDLE_REQUEST_OUTPUT) {
			int val = !!handlereq.default_values[i];

			ret = gpiod_direction_output(desc, val);
			if (ret)
				goto out_free_lh;
		} else if (lflags & GPIOHANDLE_REQUEST_INPUT) {
			ret = gpiod_direction_input(desc);
			if (ret)
				goto out_free_lh;
		}

		gpiod_line_state_notify(desc, GPIO_V2_LINE_CHANGED_REQUESTED);

		dev_dbg(&gdev->dev, "registered chardev handle for line %d\n",
			offset);
	}

	fd = get_unused_fd_flags(O_RDONLY | O_CLOEXEC);
	if (fd < 0) {
		ret = fd;
		goto out_free_lh;
	}

	file = anon_inode_getfile("gpio-linehandle",
				  &linehandle_fileops,
				  lh,
				  O_RDONLY | O_CLOEXEC);
	if (IS_ERR(file)) {
		ret = PTR_ERR(file);
		goto out_put_unused_fd;
	}

	handlereq.fd = fd;
	if (copy_to_user(ip, &handlereq, sizeof(handlereq))) {
		/*
		 * fput() will trigger the release() callback, so do not go onto
		 * the regular error cleanup path here.
		 */
		fput(file);
		put_unused_fd(fd);
		return -EFAULT;
	}

	fd_install(fd, file);

	dev_dbg(&gdev->dev, "registered chardev handle for %d lines\n",
		lh->num_descs);

	return 0;

out_put_unused_fd:
	put_unused_fd(fd);
out_free_lh:
	linehandle_free(lh);
	return ret;
}
#endif /* CONFIG_GPIO_CDEV_V1 */

/**
 * struct line - contains the state of a requested line
 * @node: to store the object in supinfo_tree if supplemental
 * @desc: the GPIO descriptor for this line.
 * @req: the corresponding line request
 * @irq: the interrupt triggered in response to events on this GPIO
 * @edflags: the edge flags, GPIO_V2_LINE_FLAG_EDGE_RISING and/or
 * GPIO_V2_LINE_FLAG_EDGE_FALLING, indicating the edge detection applied
 * @timestamp_ns: cache for the timestamp storing it between hardirq and
 * IRQ thread, used to bring the timestamp close to the actual event
 * @req_seqno: the seqno for the current edge event in the sequence of
 * events for the corresponding line request. This is drawn from the @req.
 * @line_seqno: the seqno for the current edge event in the sequence of
 * events for this line.
 * @work: the worker that implements software debouncing
 * @debounce_period_us: the debounce period in microseconds
 * @sw_debounced: flag indicating if the software debouncer is active
 * @level: the current debounced physical level of the line
 * @hdesc: the Hardware Timestamp Engine (HTE) descriptor
 * @raw_level: the line level at the time of event
 * @total_discard_seq: the running counter of the discarded events
 * @last_seqno: the last sequence number before debounce period expires
 */
struct line {
	struct rb_node node;
	struct gpio_desc *desc;
	/*
	 * -- edge detector specific fields --
	 */
	struct linereq *req;
	unsigned int irq;
	/*
	 * The flags for the active edge detector configuration.
	 *
	 * edflags is set by linereq_create(), linereq_free(), and
	 * linereq_set_config_unlocked(), which are themselves mutually
	 * exclusive, and is accessed by edge_irq_thread(),
	 * process_hw_ts_thread() and debounce_work_func(),
	 * which can all live with a slightly stale value.
	 */
	u64 edflags;
	/*
	 * timestamp_ns and req_seqno are accessed only by
	 * edge_irq_handler() and edge_irq_thread(), which are themselves
	 * mutually exclusive, so no additional protection is necessary.
	 */
	u64 timestamp_ns;
	u32 req_seqno;
	/*
	 * line_seqno is accessed by either edge_irq_thread() or
	 * debounce_work_func(), which are themselves mutually exclusive,
	 * so no additional protection is necessary.
	 */
	u32 line_seqno;
	/*
	 * -- debouncer specific fields --
	 */
	struct delayed_work work;
	/*
	 * debounce_period_us is accessed by debounce_irq_handler() and
	 * process_hw_ts() which are disabled when modified by
	 * debounce_setup(), edge_detector_setup() or edge_detector_stop()
	 * or can live with a stale version when updated by
	 * edge_detector_update().
	 * The modifying functions are themselves mutually exclusive.
	 */
	unsigned int debounce_period_us;
	/*
	 * sw_debounce is accessed by linereq_set_config(), which is the
	 * only setter, and linereq_get_values(), which can live with a
	 * slightly stale value.
	 */
	unsigned int sw_debounced;
	/*
	 * level is accessed by debounce_work_func(), which is the only
	 * setter, and linereq_get_values() which can live with a slightly
	 * stale value.
	 */
	unsigned int level;
#ifdef CONFIG_HTE
	struct hte_ts_desc hdesc;
	/*
	 * HTE provider sets line level at the time of event. The valid
	 * value is 0 or 1 and negative value for an error.
	 */
	int raw_level;
	/*
	 * when sw_debounce is set on HTE enabled line, this is running
	 * counter of the discarded events.
	 */
	u32 total_discard_seq;
	/*
	 * when sw_debounce is set on HTE enabled line, this variable records
	 * last sequence number before debounce period expires.
	 */
	u32 last_seqno;
#endif /* CONFIG_HTE */
};

/*
 * a rbtree of the struct lines containing supplemental info.
 * Used to populate gpio_v2_line_info with cdev specific fields not contained
 * in the struct gpio_desc.
 * A line is determined to contain supplemental information by
 * line_has_supinfo().
 */
static struct rb_root supinfo_tree = RB_ROOT;
/* covers supinfo_tree */
static DEFINE_SPINLOCK(supinfo_lock);

/**
 * struct linereq - contains the state of a userspace line request
 * @gdev: the GPIO device the line request pertains to
 * @label: consumer label used to tag GPIO descriptors
 * @num_lines: the number of lines in the lines array
 * @wait: wait queue that handles blocking reads of events
 * @device_unregistered_nb: notifier block for receiving gdev unregister events
 * @event_buffer_size: the number of elements allocated in @events
 * @events: KFIFO for the GPIO events
 * @seqno: the sequence number for edge events generated on all lines in
 * this line request.  Note that this is not used when @num_lines is 1, as
 * the line_seqno is then the same and is cheaper to calculate.
 * @config_mutex: mutex for serializing ioctl() calls to ensure consistency
 * of configuration, particularly multi-step accesses to desc flags and
 * changes to supinfo status.
 * @lines: the lines held by this line request, with @num_lines elements.
 */
struct linereq {
	struct gpio_device *gdev;
	const char *label;
	u32 num_lines;
	wait_queue_head_t wait;
	struct notifier_block device_unregistered_nb;
	u32 event_buffer_size;
	DECLARE_KFIFO_PTR(events, struct gpio_v2_line_event);
	atomic_t seqno;
	struct mutex config_mutex;
	struct line lines[] __counted_by(num_lines);
};

static void supinfo_insert(struct line *line)
{
	struct rb_node **new = &(supinfo_tree.rb_node), *parent = NULL;
	struct line *entry;

	guard(spinlock)(&supinfo_lock);

	while (*new) {
		entry = container_of(*new, struct line, node);

		parent = *new;
		if (line->desc < entry->desc) {
			new = &((*new)->rb_left);
		} else if (line->desc > entry->desc) {
			new = &((*new)->rb_right);
		} else {
			/* this should never happen */
			WARN(1, "duplicate line inserted");
			return;
		}
	}

	rb_link_node(&line->node, parent, new);
	rb_insert_color(&line->node, &supinfo_tree);
}

static void supinfo_erase(struct line *line)
{
	guard(spinlock)(&supinfo_lock);

	rb_erase(&line->node, &supinfo_tree);
}

static struct line *supinfo_find(struct gpio_desc *desc)
{
	struct rb_node *node = supinfo_tree.rb_node;
	struct line *line;

	while (node) {
		line = container_of(node, struct line, node);
		if (desc < line->desc)
			node = node->rb_left;
		else if (desc > line->desc)
			node = node->rb_right;
		else
			return line;
	}
	return NULL;
}

static void supinfo_to_lineinfo(struct gpio_desc *desc,
				struct gpio_v2_line_info *info)
{
	struct gpio_v2_line_attribute *attr;
	struct line *line;

	guard(spinlock)(&supinfo_lock);

	line = supinfo_find(desc);
	if (!line)
		return;

	attr = &info->attrs[info->num_attrs];
	attr->id = GPIO_V2_LINE_ATTR_ID_DEBOUNCE;
	attr->debounce_period_us = READ_ONCE(line->debounce_period_us);
	info->num_attrs++;
}

static inline bool line_has_supinfo(struct line *line)
{
	return READ_ONCE(line->debounce_period_us);
}

/*
 * Checks line_has_supinfo() before and after the change to avoid unnecessary
 * supinfo_tree access.
 * Called indirectly by linereq_create() or linereq_set_config() so line
 * is already protected from concurrent changes.
 */
static void line_set_debounce_period(struct line *line,
				     unsigned int debounce_period_us)
{
	bool was_suppl = line_has_supinfo(line);

	WRITE_ONCE(line->debounce_period_us, debounce_period_us);

	/* if supinfo status is unchanged then we're done */
	if (line_has_supinfo(line) == was_suppl)
		return;

	/* supinfo status has changed, so update the tree */
	if (was_suppl)
		supinfo_erase(line);
	else
		supinfo_insert(line);
}

#define GPIO_V2_LINE_BIAS_FLAGS \
	(GPIO_V2_LINE_FLAG_BIAS_PULL_UP | \
	 GPIO_V2_LINE_FLAG_BIAS_PULL_DOWN | \
	 GPIO_V2_LINE_FLAG_BIAS_DISABLED)

#define GPIO_V2_LINE_DIRECTION_FLAGS \
	(GPIO_V2_LINE_FLAG_INPUT | \
	 GPIO_V2_LINE_FLAG_OUTPUT)

#define GPIO_V2_LINE_DRIVE_FLAGS \
	(GPIO_V2_LINE_FLAG_OPEN_DRAIN | \
	 GPIO_V2_LINE_FLAG_OPEN_SOURCE)

#define GPIO_V2_LINE_EDGE_FLAGS \
	(GPIO_V2_LINE_FLAG_EDGE_RISING | \
	 GPIO_V2_LINE_FLAG_EDGE_FALLING)

#define GPIO_V2_LINE_FLAG_EDGE_BOTH GPIO_V2_LINE_EDGE_FLAGS

#define GPIO_V2_LINE_VALID_FLAGS \
	(GPIO_V2_LINE_FLAG_ACTIVE_LOW | \
	 GPIO_V2_LINE_DIRECTION_FLAGS | \
	 GPIO_V2_LINE_DRIVE_FLAGS | \
	 GPIO_V2_LINE_EDGE_FLAGS | \
	 GPIO_V2_LINE_FLAG_EVENT_CLOCK_REALTIME | \
	 GPIO_V2_LINE_FLAG_EVENT_CLOCK_HTE | \
	 GPIO_V2_LINE_BIAS_FLAGS)

/* subset of flags relevant for edge detector configuration */
#define GPIO_V2_LINE_EDGE_DETECTOR_FLAGS \
	(GPIO_V2_LINE_FLAG_ACTIVE_LOW | \
	 GPIO_V2_LINE_FLAG_EVENT_CLOCK_HTE | \
	 GPIO_V2_LINE_EDGE_FLAGS)

static int linereq_unregistered_notify(struct notifier_block *nb,
				       unsigned long action, void *data)
{
	struct linereq *lr = container_of(nb, struct linereq,
					  device_unregistered_nb);

	wake_up_poll(&lr->wait, EPOLLIN | EPOLLERR);

	return NOTIFY_OK;
}

static void linereq_put_event(struct linereq *lr,
			      struct gpio_v2_line_event *le)
{
	bool overflow = false;

	scoped_guard(spinlock, &lr->wait.lock) {
		if (kfifo_is_full(&lr->events)) {
			overflow = true;
			kfifo_skip(&lr->events);
		}
		kfifo_in(&lr->events, le, 1);
	}
	if (!overflow)
		wake_up_poll(&lr->wait, EPOLLIN);
	else
		pr_debug_ratelimited("event FIFO is full - event dropped\n");
}

static u64 line_event_timestamp(struct line *line)
{
	if (test_bit(FLAG_EVENT_CLOCK_REALTIME, &line->desc->flags))
		return ktime_get_real_ns();
	else if (IS_ENABLED(CONFIG_HTE) &&
		 test_bit(FLAG_EVENT_CLOCK_HTE, &line->desc->flags))
		return line->timestamp_ns;

	return ktime_get_ns();
}

static u32 line_event_id(int level)
{
	return level ? GPIO_V2_LINE_EVENT_RISING_EDGE :
		       GPIO_V2_LINE_EVENT_FALLING_EDGE;
}

static inline char *make_irq_label(const char *orig)
{
	char *new;

	if (!orig)
		return NULL;

	new = kstrdup_and_replace(orig, '/', ':', GFP_KERNEL);
	if (!new)
		return ERR_PTR(-ENOMEM);

	return new;
}

static inline void free_irq_label(const char *label)
{
	kfree(label);
}

#ifdef CONFIG_HTE

static enum hte_return process_hw_ts_thread(void *p)
{
	struct line *line;
	struct linereq *lr;
	struct gpio_v2_line_event le;
	u64 edflags;
	int level;

	if (!p)
		return HTE_CB_HANDLED;

	line = p;
	lr = line->req;

	memset(&le, 0, sizeof(le));

	le.timestamp_ns = line->timestamp_ns;
	edflags = READ_ONCE(line->edflags);

	switch (edflags & GPIO_V2_LINE_EDGE_FLAGS) {
	case GPIO_V2_LINE_FLAG_EDGE_BOTH:
		level = (line->raw_level >= 0) ?
				line->raw_level :
				gpiod_get_raw_value_cansleep(line->desc);

		if (edflags & GPIO_V2_LINE_FLAG_ACTIVE_LOW)
			level = !level;

		le.id = line_event_id(level);
		break;
	case GPIO_V2_LINE_FLAG_EDGE_RISING:
		le.id = GPIO_V2_LINE_EVENT_RISING_EDGE;
		break;
	case GPIO_V2_LINE_FLAG_EDGE_FALLING:
		le.id = GPIO_V2_LINE_EVENT_FALLING_EDGE;
		break;
	default:
		return HTE_CB_HANDLED;
	}
	le.line_seqno = line->line_seqno;
	le.seqno = (lr->num_lines == 1) ? le.line_seqno : line->req_seqno;
	le.offset = gpio_chip_hwgpio(line->desc);

	linereq_put_event(lr, &le);

	return HTE_CB_HANDLED;
}

static enum hte_return process_hw_ts(struct hte_ts_data *ts, void *p)
{
	struct line *line;
	struct linereq *lr;
	int diff_seqno = 0;

	if (!ts || !p)
		return HTE_CB_HANDLED;

	line = p;
	line->timestamp_ns = ts->tsc;
	line->raw_level = ts->raw_level;
	lr = line->req;

	if (READ_ONCE(line->sw_debounced)) {
		line->total_discard_seq++;
		line->last_seqno = ts->seq;
		mod_delayed_work(system_wq, &line->work,
		  usecs_to_jiffies(READ_ONCE(line->debounce_period_us)));
	} else {
		if (unlikely(ts->seq < line->line_seqno))
			return HTE_CB_HANDLED;

		diff_seqno = ts->seq - line->line_seqno;
		line->line_seqno = ts->seq;
		if (lr->num_lines != 1)
			line->req_seqno = atomic_add_return(diff_seqno,
							    &lr->seqno);

		return HTE_RUN_SECOND_CB;
	}

	return HTE_CB_HANDLED;
}

static int hte_edge_setup(struct line *line, u64 eflags)
{
	int ret;
	unsigned long flags = 0;
	struct hte_ts_desc *hdesc = &line->hdesc;

	if (eflags & GPIO_V2_LINE_FLAG_EDGE_RISING)
		flags |= test_bit(FLAG_ACTIVE_LOW, &line->desc->flags) ?
				 HTE_FALLING_EDGE_TS :
				 HTE_RISING_EDGE_TS;
	if (eflags & GPIO_V2_LINE_FLAG_EDGE_FALLING)
		flags |= test_bit(FLAG_ACTIVE_LOW, &line->desc->flags) ?
				 HTE_RISING_EDGE_TS :
				 HTE_FALLING_EDGE_TS;

	line->total_discard_seq = 0;

	hte_init_line_attr(hdesc, desc_to_gpio(line->desc), flags, NULL,
			   line->desc);

	ret = hte_ts_get(NULL, hdesc, 0);
	if (ret)
		return ret;

	return hte_request_ts_ns(hdesc, process_hw_ts, process_hw_ts_thread,
				 line);
}

#else

static int hte_edge_setup(struct line *line, u64 eflags)
{
	return 0;
}
#endif /* CONFIG_HTE */

static irqreturn_t edge_irq_thread(int irq, void *p)
{
	struct line *line = p;
	struct linereq *lr = line->req;
	struct gpio_v2_line_event le;

	/* Do not leak kernel stack to userspace */
	memset(&le, 0, sizeof(le));

	if (line->timestamp_ns) {
		le.timestamp_ns = line->timestamp_ns;
	} else {
		/*
		 * We may be running from a nested threaded interrupt in
		 * which case we didn't get the timestamp from
		 * edge_irq_handler().
		 */
		le.timestamp_ns = line_event_timestamp(line);
		if (lr->num_lines != 1)
			line->req_seqno = atomic_inc_return(&lr->seqno);
	}
	line->timestamp_ns = 0;

	switch (READ_ONCE(line->edflags) & GPIO_V2_LINE_EDGE_FLAGS) {
	case GPIO_V2_LINE_FLAG_EDGE_BOTH:
		le.id = line_event_id(gpiod_get_value_cansleep(line->desc));
		break;
	case GPIO_V2_LINE_FLAG_EDGE_RISING:
		le.id = GPIO_V2_LINE_EVENT_RISING_EDGE;
		break;
	case GPIO_V2_LINE_FLAG_EDGE_FALLING:
		le.id = GPIO_V2_LINE_EVENT_FALLING_EDGE;
		break;
	default:
		return IRQ_NONE;
	}
	line->line_seqno++;
	le.line_seqno = line->line_seqno;
	le.seqno = (lr->num_lines == 1) ? le.line_seqno : line->req_seqno;
	le.offset = gpio_chip_hwgpio(line->desc);

	linereq_put_event(lr, &le);

	return IRQ_HANDLED;
}

static irqreturn_t edge_irq_handler(int irq, void *p)
{
	struct line *line = p;
	struct linereq *lr = line->req;

	/*
	 * Just store the timestamp in hardirq context so we get it as
	 * close in time as possible to the actual event.
	 */
	line->timestamp_ns = line_event_timestamp(line);

	if (lr->num_lines != 1)
		line->req_seqno = atomic_inc_return(&lr->seqno);

	return IRQ_WAKE_THREAD;
}

/*
 * returns the current debounced logical value.
 */
static bool debounced_value(struct line *line)
{
	bool value;

	/*
	 * minor race - debouncer may be stopped here, so edge_detector_stop()
	 * must leave the value unchanged so the following will read the level
	 * from when the debouncer was last running.
	 */
	value = READ_ONCE(line->level);

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

	return value;
}

static irqreturn_t debounce_irq_handler(int irq, void *p)
{
	struct line *line = p;

	mod_delayed_work(system_wq, &line->work,
		usecs_to_jiffies(READ_ONCE(line->debounce_period_us)));

	return IRQ_HANDLED;
}

static void debounce_work_func(struct work_struct *work)
{
	struct gpio_v2_line_event le;
	struct line *line = container_of(work, struct line, work.work);
	struct linereq *lr;
	u64 eflags, edflags = READ_ONCE(line->edflags);
	int level = -1;
#ifdef CONFIG_HTE
	int diff_seqno;

	if (edflags & GPIO_V2_LINE_FLAG_EVENT_CLOCK_HTE)
		level = line->raw_level;
#endif
	if (level < 0)
		level = gpiod_get_raw_value_cansleep(line->desc);
	if (level < 0) {
		pr_debug_ratelimited("debouncer failed to read line value\n");
		return;
	}

	if (READ_ONCE(line->level) == level)
		return;

	WRITE_ONCE(line->level, level);

	/* -- edge detection -- */
	eflags = edflags & GPIO_V2_LINE_EDGE_FLAGS;
	if (!eflags)
		return;

	/* switch from physical level to logical - if they differ */
	if (edflags & GPIO_V2_LINE_FLAG_ACTIVE_LOW)
		level = !level;

	/* ignore edges that are not being monitored */
	if (((eflags == GPIO_V2_LINE_FLAG_EDGE_RISING) && !level) ||
	    ((eflags == GPIO_V2_LINE_FLAG_EDGE_FALLING) && level))
		return;

	/* Do not leak kernel stack to userspace */
	memset(&le, 0, sizeof(le));

	lr = line->req;
	le.timestamp_ns = line_event_timestamp(line);
	le.offset = gpio_chip_hwgpio(line->desc);
#ifdef CONFIG_HTE
	if (edflags & GPIO_V2_LINE_FLAG_EVENT_CLOCK_HTE) {
		/* discard events except the last one */
		line->total_discard_seq -= 1;
		diff_seqno = line->last_seqno - line->total_discard_seq -
				line->line_seqno;
		line->line_seqno = line->last_seqno - line->total_discard_seq;
		le.line_seqno = line->line_seqno;
		le.seqno = (lr->num_lines == 1) ?
			le.line_seqno : atomic_add_return(diff_seqno, &lr->seqno);
	} else
#endif /* CONFIG_HTE */
	{
		line->line_seqno++;
		le.line_seqno = line->line_seqno;
		le.seqno = (lr->num_lines == 1) ?
			le.line_seqno : atomic_inc_return(&lr->seqno);
	}

	le.id = line_event_id(level);

	linereq_put_event(lr, &le);
}

static int debounce_setup(struct line *line, unsigned int debounce_period_us)
{
	unsigned long irqflags;
	int ret, level, irq;
	char *label;

	/* try hardware */
	ret = gpiod_set_debounce(line->desc, debounce_period_us);
	if (!ret) {
		line_set_debounce_period(line, debounce_period_us);
		return ret;
	}
	if (ret != -ENOTSUPP)
		return ret;

	if (debounce_period_us) {
		/* setup software debounce */
		level = gpiod_get_raw_value_cansleep(line->desc);
		if (level < 0)
			return level;

		if (!(IS_ENABLED(CONFIG_HTE) &&
		      test_bit(FLAG_EVENT_CLOCK_HTE, &line->desc->flags))) {
			irq = gpiod_to_irq(line->desc);
			if (irq < 0)
				return -ENXIO;

			label = make_irq_label(line->req->label);
			if (IS_ERR(label))
				return -ENOMEM;

			irqflags = IRQF_TRIGGER_FALLING | IRQF_TRIGGER_RISING;
			ret = request_irq(irq, debounce_irq_handler, irqflags,
					  label, line);
			if (ret) {
				free_irq_label(label);
				return ret;
			}
			line->irq = irq;
		} else {
			ret = hte_edge_setup(line, GPIO_V2_LINE_FLAG_EDGE_BOTH);
			if (ret)
				return ret;
		}

		WRITE_ONCE(line->level, level);
		WRITE_ONCE(line->sw_debounced, 1);
	}
	return 0;
}

static bool gpio_v2_line_config_debounced(struct gpio_v2_line_config *lc,
					  unsigned int line_idx)
{
	unsigned int i;
	u64 mask = BIT_ULL(line_idx);

	for (i = 0; i < lc->num_attrs; i++) {
		if ((lc->attrs[i].attr.id == GPIO_V2_LINE_ATTR_ID_DEBOUNCE) &&
		    (lc->attrs[i].mask & mask))
			return true;
	}
	return false;
}

static u32 gpio_v2_line_config_debounce_period(struct gpio_v2_line_config *lc,
					       unsigned int line_idx)
{
	unsigned int i;
	u64 mask = BIT_ULL(line_idx);

	for (i = 0; i < lc->num_attrs; i++) {
		if ((lc->attrs[i].attr.id == GPIO_V2_LINE_ATTR_ID_DEBOUNCE) &&
		    (lc->attrs[i].mask & mask))
			return lc->attrs[i].attr.debounce_period_us;
	}
	return 0;
}

static void edge_detector_stop(struct line *line)
{
	if (line->irq) {
		free_irq_label(free_irq(line->irq, line));
		line->irq = 0;
	}

#ifdef CONFIG_HTE
	if (READ_ONCE(line->edflags) & GPIO_V2_LINE_FLAG_EVENT_CLOCK_HTE)
		hte_ts_put(&line->hdesc);
#endif

	cancel_delayed_work_sync(&line->work);
	WRITE_ONCE(line->sw_debounced, 0);
	WRITE_ONCE(line->edflags, 0);
	line_set_debounce_period(line, 0);
	/* do not change line->level - see comment in debounced_value() */
}

static int edge_detector_setup(struct line *line,
			       struct gpio_v2_line_config *lc,
			       unsigned int line_idx, u64 edflags)
{
	u32 debounce_period_us;
	unsigned long irqflags = 0;
	u64 eflags;
	int irq, ret;
	char *label;

	eflags = edflags & GPIO_V2_LINE_EDGE_FLAGS;
	if (eflags && !kfifo_initialized(&line->req->events)) {
		ret = kfifo_alloc(&line->req->events,
				  line->req->event_buffer_size, GFP_KERNEL);
		if (ret)
			return ret;
	}
	if (gpio_v2_line_config_debounced(lc, line_idx)) {
		debounce_period_us = gpio_v2_line_config_debounce_period(lc, line_idx);
		ret = debounce_setup(line, debounce_period_us);
		if (ret)
			return ret;
		line_set_debounce_period(line, debounce_period_us);
	}

	/* detection disabled or sw debouncer will provide edge detection */
	if (!eflags || READ_ONCE(line->sw_debounced))
		return 0;

	if (IS_ENABLED(CONFIG_HTE) &&
	    (edflags & GPIO_V2_LINE_FLAG_EVENT_CLOCK_HTE))
		return hte_edge_setup(line, edflags);

	irq = gpiod_to_irq(line->desc);
	if (irq < 0)
		return -ENXIO;

	if (eflags & GPIO_V2_LINE_FLAG_EDGE_RISING)
		irqflags |= test_bit(FLAG_ACTIVE_LOW, &line->desc->flags) ?
			IRQF_TRIGGER_FALLING : IRQF_TRIGGER_RISING;
	if (eflags & GPIO_V2_LINE_FLAG_EDGE_FALLING)
		irqflags |= test_bit(FLAG_ACTIVE_LOW, &line->desc->flags) ?
			IRQF_TRIGGER_RISING : IRQF_TRIGGER_FALLING;
	irqflags |= IRQF_ONESHOT;

	label = make_irq_label(line->req->label);
	if (IS_ERR(label))
		return PTR_ERR(label);

	/* Request a thread to read the events */
	ret = request_threaded_irq(irq, edge_irq_handler, edge_irq_thread,
				   irqflags, label, line);
	if (ret) {
		free_irq_label(label);
		return ret;
	}

	line->irq = irq;
	return 0;
}

static int edge_detector_update(struct line *line,
				struct gpio_v2_line_config *lc,
				unsigned int line_idx, u64 edflags)
{
	u64 eflags;
	int ret;
	u64 active_edflags = READ_ONCE(line->edflags);
	unsigned int debounce_period_us =
			gpio_v2_line_config_debounce_period(lc, line_idx);

	if ((active_edflags == edflags) &&
	    (READ_ONCE(line->debounce_period_us) == debounce_period_us))
		return 0;

	/* sw debounced and still will be...*/
	if (debounce_period_us && READ_ONCE(line->sw_debounced)) {
		line_set_debounce_period(line, debounce_period_us);
		/*
		 * ensure event fifo is initialised if edge detection
		 * is now enabled.
		 */
		eflags = edflags & GPIO_V2_LINE_EDGE_FLAGS;
		if (eflags && !kfifo_initialized(&line->req->events)) {
			ret = kfifo_alloc(&line->req->events,
					  line->req->event_buffer_size,
					  GFP_KERNEL);
			if (ret)
				return ret;
		}
		return 0;
	}

	/* reconfiguring edge detection or sw debounce being disabled */
	if ((line->irq && !READ_ONCE(line->sw_debounced)) ||
	    (active_edflags & GPIO_V2_LINE_FLAG_EVENT_CLOCK_HTE) ||
	    (!debounce_period_us && READ_ONCE(line->sw_debounced)))
		edge_detector_stop(line);

	return edge_detector_setup(line, lc, line_idx, edflags);
}

static u64 gpio_v2_line_config_flags(struct gpio_v2_line_config *lc,
				     unsigned int line_idx)
{
	unsigned int i;
	u64 mask = BIT_ULL(line_idx);

	for (i = 0; i < lc->num_attrs; i++) {
		if ((lc->attrs[i].attr.id == GPIO_V2_LINE_ATTR_ID_FLAGS) &&
		    (lc->attrs[i].mask & mask))
			return lc->attrs[i].attr.flags;
	}
	return lc->flags;
}

static int gpio_v2_line_config_output_value(struct gpio_v2_line_config *lc,
					    unsigned int line_idx)
{
	unsigned int i;
	u64 mask = BIT_ULL(line_idx);

	for (i = 0; i < lc->num_attrs; i++) {
		if ((lc->attrs[i].attr.id == GPIO_V2_LINE_ATTR_ID_OUTPUT_VALUES) &&
		    (lc->attrs[i].mask & mask))
			return !!(lc->attrs[i].attr.values & mask);
	}
	return 0;
}

static int gpio_v2_line_flags_validate(u64 flags)
{
	/* Return an error if an unknown flag is set */
	if (flags & ~GPIO_V2_LINE_VALID_FLAGS)
		return -EINVAL;

	if (!IS_ENABLED(CONFIG_HTE) &&
	    (flags & GPIO_V2_LINE_FLAG_EVENT_CLOCK_HTE))
		return -EOPNOTSUPP;

	/*
	 * Do not allow both INPUT and OUTPUT flags to be set as they are
	 * contradictory.
	 */
	if ((flags & GPIO_V2_LINE_FLAG_INPUT) &&
	    (flags & GPIO_V2_LINE_FLAG_OUTPUT))
		return -EINVAL;

	/* Only allow one event clock source */
	if (IS_ENABLED(CONFIG_HTE) &&
	    (flags & GPIO_V2_LINE_FLAG_EVENT_CLOCK_REALTIME) &&
	    (flags & GPIO_V2_LINE_FLAG_EVENT_CLOCK_HTE))
		return -EINVAL;

	/* Edge detection requires explicit input. */
	if ((flags & GPIO_V2_LINE_EDGE_FLAGS) &&
	    !(flags & GPIO_V2_LINE_FLAG_INPUT))
		return -EINVAL;

	/*
	 * Do not allow OPEN_SOURCE and OPEN_DRAIN flags in a single
	 * request. If the hardware actually supports enabling both at the
	 * same time the electrical result would be disastrous.
	 */
	if ((flags & GPIO_V2_LINE_FLAG_OPEN_DRAIN) &&
	    (flags & GPIO_V2_LINE_FLAG_OPEN_SOURCE))
		return -EINVAL;

	/* Drive requires explicit output direction. */
	if ((flags & GPIO_V2_LINE_DRIVE_FLAGS) &&
	    !(flags & GPIO_V2_LINE_FLAG_OUTPUT))
		return -EINVAL;

	/* Bias requires explicit direction. */
	if ((flags & GPIO_V2_LINE_BIAS_FLAGS) &&
	    !(flags & GPIO_V2_LINE_DIRECTION_FLAGS))
		return -EINVAL;

	/* Only one bias flag can be set. */
	if (((flags & GPIO_V2_LINE_FLAG_BIAS_DISABLED) &&
	     (flags & (GPIO_V2_LINE_FLAG_BIAS_PULL_DOWN |
		       GPIO_V2_LINE_FLAG_BIAS_PULL_UP))) ||
	    ((flags & GPIO_V2_LINE_FLAG_BIAS_PULL_DOWN) &&
	     (flags & GPIO_V2_LINE_FLAG_BIAS_PULL_UP)))
		return -EINVAL;

	return 0;
}

static int gpio_v2_line_config_validate(struct gpio_v2_line_config *lc,
					unsigned int num_lines)
{
	unsigned int i;
	u64 flags;
	int ret;

	if (lc->num_attrs > GPIO_V2_LINE_NUM_ATTRS_MAX)
		return -EINVAL;

	if (memchr_inv(lc->padding, 0, sizeof(lc->padding)))
		return -EINVAL;

	for (i = 0; i < num_lines; i++) {
		flags = gpio_v2_line_config_flags(lc, i);
		ret = gpio_v2_line_flags_validate(flags);
		if (ret)
			return ret;

		/* debounce requires explicit input */
		if (gpio_v2_line_config_debounced(lc, i) &&
		    !(flags & GPIO_V2_LINE_FLAG_INPUT))
			return -EINVAL;
	}
	return 0;
}

static void gpio_v2_line_config_flags_to_desc_flags(u64 flags,
						    unsigned long *flagsp)
{
	assign_bit(FLAG_ACTIVE_LOW, flagsp,
		   flags & GPIO_V2_LINE_FLAG_ACTIVE_LOW);

	if (flags & GPIO_V2_LINE_FLAG_OUTPUT)
		set_bit(FLAG_IS_OUT, flagsp);
	else if (flags & GPIO_V2_LINE_FLAG_INPUT)
		clear_bit(FLAG_IS_OUT, flagsp);

	assign_bit(FLAG_EDGE_RISING, flagsp,
		   flags & GPIO_V2_LINE_FLAG_EDGE_RISING);
	assign_bit(FLAG_EDGE_FALLING, flagsp,
		   flags & GPIO_V2_LINE_FLAG_EDGE_FALLING);

	assign_bit(FLAG_OPEN_DRAIN, flagsp,
		   flags & GPIO_V2_LINE_FLAG_OPEN_DRAIN);
	assign_bit(FLAG_OPEN_SOURCE, flagsp,
		   flags & GPIO_V2_LINE_FLAG_OPEN_SOURCE);

	assign_bit(FLAG_PULL_UP, flagsp,
		   flags & GPIO_V2_LINE_FLAG_BIAS_PULL_UP);
	assign_bit(FLAG_PULL_DOWN, flagsp,
		   flags & GPIO_V2_LINE_FLAG_BIAS_PULL_DOWN);
	assign_bit(FLAG_BIAS_DISABLE, flagsp,
		   flags & GPIO_V2_LINE_FLAG_BIAS_DISABLED);

	assign_bit(FLAG_EVENT_CLOCK_REALTIME, flagsp,
		   flags & GPIO_V2_LINE_FLAG_EVENT_CLOCK_REALTIME);
	assign_bit(FLAG_EVENT_CLOCK_HTE, flagsp,
		   flags & GPIO_V2_LINE_FLAG_EVENT_CLOCK_HTE);
}

static long linereq_get_values(struct linereq *lr, void __user *ip)
{
	struct gpio_v2_line_values lv;
	DECLARE_BITMAP(vals, GPIO_V2_LINES_MAX);
	struct gpio_desc **descs;
	unsigned int i, didx, num_get;
	bool val;
	int ret;

	/* NOTE: It's ok to read values of output lines. */
	if (copy_from_user(&lv, ip, sizeof(lv)))
		return -EFAULT;

	/*
	 * gpiod_get_array_value_complex() requires compacted desc and val
	 * arrays, rather than the sparse ones in lv.
	 * Calculation of num_get and construction of the desc array is
	 * optimized to avoid allocation for the desc array for the common
	 * num_get == 1 case.
	 */
	/* scan requested lines to calculate the subset to get */
	for (num_get = 0, i = 0; i < lr->num_lines; i++) {
		if (lv.mask & BIT_ULL(i)) {
			num_get++;
			/* capture desc for the num_get == 1 case */
			descs = &lr->lines[i].desc;
		}
	}

	if (num_get == 0)
		return -EINVAL;

	if (num_get != 1) {
		/* build compacted desc array */
		descs = kmalloc_array(num_get, sizeof(*descs), GFP_KERNEL);
		if (!descs)
			return -ENOMEM;
		for (didx = 0, i = 0; i < lr->num_lines; i++) {
			if (lv.mask & BIT_ULL(i)) {
				descs[didx] = lr->lines[i].desc;
				didx++;
			}
		}
	}
	ret = gpiod_get_array_value_complex(false, true, num_get,
					    descs, NULL, vals);

	if (num_get != 1)
		kfree(descs);
	if (ret)
		return ret;

	lv.bits = 0;
	for (didx = 0, i = 0; i < lr->num_lines; i++) {
		/* unpack compacted vals for the response */
		if (lv.mask & BIT_ULL(i)) {
			if (lr->lines[i].sw_debounced)
				val = debounced_value(&lr->lines[i]);
			else
				val = test_bit(didx, vals);
			if (val)
				lv.bits |= BIT_ULL(i);
			didx++;
		}
	}

	if (copy_to_user(ip, &lv, sizeof(lv)))
		return -EFAULT;

	return 0;
}

static long linereq_set_values(struct linereq *lr, void __user *ip)
{
	DECLARE_BITMAP(vals, GPIO_V2_LINES_MAX);
	struct gpio_v2_line_values lv;
	struct gpio_desc **descs;
	unsigned int i, didx, num_set;
	int ret;

	if (copy_from_user(&lv, ip, sizeof(lv)))
		return -EFAULT;

	guard(mutex)(&lr->config_mutex);

	/*
	 * gpiod_set_array_value_complex() requires compacted desc and val
	 * arrays, rather than the sparse ones in lv.
	 * Calculation of num_set and construction of the descs and vals arrays
	 * is optimized to minimize scanning the lv->mask, and to avoid
	 * allocation for the desc array for the common num_set == 1 case.
	 */
	bitmap_zero(vals, GPIO_V2_LINES_MAX);
	/* scan requested lines to determine the subset to be set */
	for (num_set = 0, i = 0; i < lr->num_lines; i++) {
		if (lv.mask & BIT_ULL(i)) {
			/* setting inputs is not allowed */
			if (!test_bit(FLAG_IS_OUT, &lr->lines[i].desc->flags))
				return -EPERM;
			/* add to compacted values */
			if (lv.bits & BIT_ULL(i))
				__set_bit(num_set, vals);
			num_set++;
			/* capture desc for the num_set == 1 case */
			descs = &lr->lines[i].desc;
		}
	}
	if (num_set == 0)
		return -EINVAL;

	if (num_set != 1) {
		/* build compacted desc array */
		descs = kmalloc_array(num_set, sizeof(*descs), GFP_KERNEL);
		if (!descs)
			return -ENOMEM;
		for (didx = 0, i = 0; i < lr->num_lines; i++) {
			if (lv.mask & BIT_ULL(i)) {
				descs[didx] = lr->lines[i].desc;
				didx++;
			}
		}
	}
	ret = gpiod_set_array_value_complex(false, true, num_set,
					    descs, NULL, vals);

	if (num_set != 1)
		kfree(descs);
	return ret;
}

static long linereq_set_config(struct linereq *lr, void __user *ip)
{
	struct gpio_v2_line_config lc;
	struct gpio_desc *desc;
	struct line *line;
	unsigned int i;
	u64 flags, edflags;
	int ret;

	if (copy_from_user(&lc, ip, sizeof(lc)))
		return -EFAULT;

	ret = gpio_v2_line_config_validate(&lc, lr->num_lines);
	if (ret)
		return ret;

	guard(mutex)(&lr->config_mutex);

	for (i = 0; i < lr->num_lines; i++) {
		line = &lr->lines[i];
		desc = lr->lines[i].desc;
		flags = gpio_v2_line_config_flags(&lc, i);
		gpio_v2_line_config_flags_to_desc_flags(flags, &desc->flags);
		edflags = flags & GPIO_V2_LINE_EDGE_DETECTOR_FLAGS;
		/*
		 * Lines have to be requested explicitly for input
		 * or output, else the line will be treated "as is".
		 */
		if (flags & GPIO_V2_LINE_FLAG_OUTPUT) {
			int val = gpio_v2_line_config_output_value(&lc, i);

			edge_detector_stop(line);
			ret = gpiod_direction_output(desc, val);
			if (ret)
				return ret;
		} else if (flags & GPIO_V2_LINE_FLAG_INPUT) {
			ret = gpiod_direction_input(desc);
			if (ret)
				return ret;

			ret = edge_detector_update(line, &lc, i, edflags);
			if (ret)
				return ret;
		}

		WRITE_ONCE(line->edflags, edflags);

		gpiod_line_state_notify(desc, GPIO_V2_LINE_CHANGED_CONFIG);
	}
	return 0;
}

static long linereq_ioctl(struct file *file, unsigned int cmd,
			  unsigned long arg)
{
	struct linereq *lr = file->private_data;
	void __user *ip = (void __user *)arg;

	guard(srcu)(&lr->gdev->srcu);

	if (!rcu_access_pointer(lr->gdev->chip))
		return -ENODEV;

	switch (cmd) {
	case GPIO_V2_LINE_GET_VALUES_IOCTL:
		return linereq_get_values(lr, ip);
	case GPIO_V2_LINE_SET_VALUES_IOCTL:
		return linereq_set_values(lr, ip);
	case GPIO_V2_LINE_SET_CONFIG_IOCTL:
		return linereq_set_config(lr, ip);
	default:
		return -EINVAL;
	}
}

#ifdef CONFIG_COMPAT
static long linereq_ioctl_compat(struct file *file, unsigned int cmd,
				 unsigned long arg)
{
	return linereq_ioctl(file, cmd, (unsigned long)compat_ptr(arg));
}
#endif

static __poll_t linereq_poll(struct file *file,
			     struct poll_table_struct *wait)
{
	struct linereq *lr = file->private_data;
	__poll_t events = 0;

	guard(srcu)(&lr->gdev->srcu);

	if (!rcu_access_pointer(lr->gdev->chip))
		return EPOLLHUP | EPOLLERR;

	poll_wait(file, &lr->wait, wait);

	if (!kfifo_is_empty_spinlocked_noirqsave(&lr->events,
						 &lr->wait.lock))
		events = EPOLLIN | EPOLLRDNORM;

	return events;
}

static ssize_t linereq_read(struct file *file, char __user *buf,
			    size_t count, loff_t *f_ps)
{
	struct linereq *lr = file->private_data;
	struct gpio_v2_line_event le;
	ssize_t bytes_read = 0;
	int ret;

	guard(srcu)(&lr->gdev->srcu);

	if (!rcu_access_pointer(lr->gdev->chip))
		return -ENODEV;

	if (count < sizeof(le))
		return -EINVAL;

	do {
		scoped_guard(spinlock, &lr->wait.lock) {
			if (kfifo_is_empty(&lr->events)) {
				if (bytes_read)
					return bytes_read;

				if (file->f_flags & O_NONBLOCK)
					return -EAGAIN;

				ret = wait_event_interruptible_locked(lr->wait,
						!kfifo_is_empty(&lr->events));
				if (ret)
					return ret;
			}

			ret = kfifo_out(&lr->events, &le, 1);
		}
		if (ret != 1) {
			/*
			 * This should never happen - we were holding the
			 * lock from the moment we learned the fifo is no
			 * longer empty until now.
			 */
			ret = -EIO;
			break;
		}

		if (copy_to_user(buf + bytes_read, &le, sizeof(le)))
			return -EFAULT;
		bytes_read += sizeof(le);
	} while (count >= bytes_read + sizeof(le));

	return bytes_read;
}

static void linereq_free(struct linereq *lr)
{
	struct line *line;
	unsigned int i;

	if (lr->device_unregistered_nb.notifier_call)
		blocking_notifier_chain_unregister(&lr->gdev->device_notifier,
						   &lr->device_unregistered_nb);

	for (i = 0; i < lr->num_lines; i++) {
		line = &lr->lines[i];
		if (!line->desc)
			continue;

		edge_detector_stop(line);
		if (line_has_supinfo(line))
			supinfo_erase(line);
		gpiod_free(line->desc);
	}
	kfifo_free(&lr->events);
	kfree(lr->label);
	gpio_device_put(lr->gdev);
	kvfree(lr);
}

static int linereq_release(struct inode *inode, struct file *file)
{
	struct linereq *lr = file->private_data;

	linereq_free(lr);
	return 0;
}

#ifdef CONFIG_PROC_FS
static void linereq_show_fdinfo(struct seq_file *out, struct file *file)
{
	struct linereq *lr = file->private_data;
	struct device *dev = &lr->gdev->dev;
	u16 i;

	seq_printf(out, "gpio-chip:\t%s\n", dev_name(dev));

	for (i = 0; i < lr->num_lines; i++)
		seq_printf(out, "gpio-line:\t%d\n",
			   gpio_chip_hwgpio(lr->lines[i].desc));
}
#endif

static const struct file_operations line_fileops = {
	.release = linereq_release,
	.read = linereq_read,
	.poll = linereq_poll,
	.owner = THIS_MODULE,
	.llseek = noop_llseek,
	.unlocked_ioctl = linereq_ioctl,
#ifdef CONFIG_COMPAT
	.compat_ioctl = linereq_ioctl_compat,
#endif
#ifdef CONFIG_PROC_FS
	.show_fdinfo = linereq_show_fdinfo,
#endif
};

static int linereq_create(struct gpio_device *gdev, void __user *ip)
{
	struct gpio_v2_line_request ulr;
	struct gpio_v2_line_config *lc;
	struct linereq *lr;
	struct file *file;
	u64 flags, edflags;
	unsigned int i;
	int fd, ret;

	if (copy_from_user(&ulr, ip, sizeof(ulr)))
		return -EFAULT;

	if ((ulr.num_lines == 0) || (ulr.num_lines > GPIO_V2_LINES_MAX))
		return -EINVAL;

	if (memchr_inv(ulr.padding, 0, sizeof(ulr.padding)))
		return -EINVAL;

	lc = &ulr.config;
	ret = gpio_v2_line_config_validate(lc, ulr.num_lines);
	if (ret)
		return ret;

	lr = kvzalloc(struct_size(lr, lines, ulr.num_lines), GFP_KERNEL);
	if (!lr)
		return -ENOMEM;
	lr->num_lines = ulr.num_lines;

	lr->gdev = gpio_device_get(gdev);

	for (i = 0; i < ulr.num_lines; i++) {
		lr->lines[i].req = lr;
		WRITE_ONCE(lr->lines[i].sw_debounced, 0);
		INIT_DELAYED_WORK(&lr->lines[i].work, debounce_work_func);
	}

	if (ulr.consumer[0] != '\0') {
		/* label is only initialized if consumer is set */
		lr->label = kstrndup(ulr.consumer, sizeof(ulr.consumer) - 1,
				     GFP_KERNEL);
		if (!lr->label) {
			ret = -ENOMEM;
			goto out_free_linereq;
		}
	}

	mutex_init(&lr->config_mutex);
	init_waitqueue_head(&lr->wait);
	lr->event_buffer_size = ulr.event_buffer_size;
	if (lr->event_buffer_size == 0)
		lr->event_buffer_size = ulr.num_lines * 16;
	else if (lr->event_buffer_size > GPIO_V2_LINES_MAX * 16)
		lr->event_buffer_size = GPIO_V2_LINES_MAX * 16;

	atomic_set(&lr->seqno, 0);

	/* Request each GPIO */
	for (i = 0; i < ulr.num_lines; i++) {
		u32 offset = ulr.offsets[i];
		struct gpio_desc *desc = gpio_device_get_desc(gdev, offset);

		if (IS_ERR(desc)) {
			ret = PTR_ERR(desc);
			goto out_free_linereq;
		}

		ret = gpiod_request_user(desc, lr->label);
		if (ret)
			goto out_free_linereq;

		lr->lines[i].desc = desc;
		flags = gpio_v2_line_config_flags(lc, i);
		gpio_v2_line_config_flags_to_desc_flags(flags, &desc->flags);

		ret = gpiod_set_transitory(desc, false);
		if (ret < 0)
			goto out_free_linereq;

		edflags = flags & GPIO_V2_LINE_EDGE_DETECTOR_FLAGS;
		/*
		 * Lines have to be requested explicitly for input
		 * or output, else the line will be treated "as is".
		 */
		if (flags & GPIO_V2_LINE_FLAG_OUTPUT) {
			int val = gpio_v2_line_config_output_value(lc, i);

			ret = gpiod_direction_output(desc, val);
			if (ret)
				goto out_free_linereq;
		} else if (flags & GPIO_V2_LINE_FLAG_INPUT) {
			ret = gpiod_direction_input(desc);
			if (ret)
				goto out_free_linereq;

			ret = edge_detector_setup(&lr->lines[i], lc, i,
						  edflags);
			if (ret)
				goto out_free_linereq;
		}

		lr->lines[i].edflags = edflags;

		gpiod_line_state_notify(desc, GPIO_V2_LINE_CHANGED_REQUESTED);

		dev_dbg(&gdev->dev, "registered chardev handle for line %d\n",
			offset);
	}

	lr->device_unregistered_nb.notifier_call = linereq_unregistered_notify;
	ret = blocking_notifier_chain_register(&gdev->device_notifier,
					       &lr->device_unregistered_nb);
	if (ret)
		goto out_free_linereq;

	fd = get_unused_fd_flags(O_RDONLY | O_CLOEXEC);
	if (fd < 0) {
		ret = fd;
		goto out_free_linereq;
	}

	file = anon_inode_getfile("gpio-line", &line_fileops, lr,
				  O_RDONLY | O_CLOEXEC);
	if (IS_ERR(file)) {
		ret = PTR_ERR(file);
		goto out_put_unused_fd;
	}

	ulr.fd = fd;
	if (copy_to_user(ip, &ulr, sizeof(ulr))) {
		/*
		 * fput() will trigger the release() callback, so do not go onto
		 * the regular error cleanup path here.
		 */
		fput(file);
		put_unused_fd(fd);
		return -EFAULT;
	}

	fd_install(fd, file);

	dev_dbg(&gdev->dev, "registered chardev handle for %d lines\n",
		lr->num_lines);

	return 0;

out_put_unused_fd:
	put_unused_fd(fd);
out_free_linereq:
	linereq_free(lr);
	return ret;
}

#ifdef CONFIG_GPIO_CDEV_V1

/*
 * GPIO line event management
 */

/**
 * struct lineevent_state - contains the state of a userspace event
 * @gdev: the GPIO device the event pertains to
 * @label: consumer label used to tag descriptors
 * @desc: the GPIO descriptor held by this event
 * @eflags: the event flags this line was requested with
 * @irq: the interrupt that trigger in response to events on this GPIO
 * @wait: wait queue that handles blocking reads of events
 * @device_unregistered_nb: notifier block for receiving gdev unregister events
 * @events: KFIFO for the GPIO events
 * @timestamp: cache for the timestamp storing it between hardirq
 * and IRQ thread, used to bring the timestamp close to the actual
 * event
 */
struct lineevent_state {
	struct gpio_device *gdev;
	const char *label;
	struct gpio_desc *desc;
	u32 eflags;
	int irq;
	wait_queue_head_t wait;
	struct notifier_block device_unregistered_nb;
	DECLARE_KFIFO(events, struct gpioevent_data, 16);
	u64 timestamp;
};

#define GPIOEVENT_REQUEST_VALID_FLAGS \
	(GPIOEVENT_REQUEST_RISING_EDGE | \
	GPIOEVENT_REQUEST_FALLING_EDGE)

static __poll_t lineevent_poll(struct file *file,
			       struct poll_table_struct *wait)
{
	struct lineevent_state *le = file->private_data;
	__poll_t events = 0;

	guard(srcu)(&le->gdev->srcu);

	if (!rcu_access_pointer(le->gdev->chip))
		return EPOLLHUP | EPOLLERR;

	poll_wait(file, &le->wait, wait);

	if (!kfifo_is_empty_spinlocked_noirqsave(&le->events, &le->wait.lock))
		events = EPOLLIN | EPOLLRDNORM;

	return events;
}

static int lineevent_unregistered_notify(struct notifier_block *nb,
					 unsigned long action, void *data)
{
	struct lineevent_state *le = container_of(nb, struct lineevent_state,
						  device_unregistered_nb);

	wake_up_poll(&le->wait, EPOLLIN | EPOLLERR);

	return NOTIFY_OK;
}

struct compat_gpioeevent_data {
	compat_u64	timestamp;
	u32		id;
};

static ssize_t lineevent_read(struct file *file, char __user *buf,
			      size_t count, loff_t *f_ps)
{
	struct lineevent_state *le = file->private_data;
	struct gpioevent_data ge;
	ssize_t bytes_read = 0;
	ssize_t ge_size;
	int ret;

	guard(srcu)(&le->gdev->srcu);

	if (!rcu_access_pointer(le->gdev->chip))
		return -ENODEV;

	/*
	 * When compatible system call is being used the struct gpioevent_data,
	 * in case of at least ia32, has different size due to the alignment
	 * differences. Because we have first member 64 bits followed by one of
	 * 32 bits there is no gap between them. The only difference is the
	 * padding at the end of the data structure. Hence, we calculate the
	 * actual sizeof() and pass this as an argument to copy_to_user() to
	 * drop unneeded bytes from the output.
	 */
	if (compat_need_64bit_alignment_fixup())
		ge_size = sizeof(struct compat_gpioeevent_data);
	else
		ge_size = sizeof(struct gpioevent_data);
	if (count < ge_size)
		return -EINVAL;

	do {
		scoped_guard(spinlock, &le->wait.lock) {
			if (kfifo_is_empty(&le->events)) {
				if (bytes_read)
					return bytes_read;

				if (file->f_flags & O_NONBLOCK)
					return -EAGAIN;

				ret = wait_event_interruptible_locked(le->wait,
						!kfifo_is_empty(&le->events));
				if (ret)
					return ret;
			}

			ret = kfifo_out(&le->events, &ge, 1);
		}
		if (ret != 1) {
			/*
			 * This should never happen - we were holding the lock
			 * from the moment we learned the fifo is no longer
			 * empty until now.
			 */
			ret = -EIO;
			break;
		}

		if (copy_to_user(buf + bytes_read, &ge, ge_size))
			return -EFAULT;
		bytes_read += ge_size;
	} while (count >= bytes_read + ge_size);

	return bytes_read;
}

static void lineevent_free(struct lineevent_state *le)
{
	if (le->device_unregistered_nb.notifier_call)
		blocking_notifier_chain_unregister(&le->gdev->device_notifier,
						   &le->device_unregistered_nb);
	if (le->irq)
		free_irq_label(free_irq(le->irq, le));
	if (le->desc)
		gpiod_free(le->desc);
	kfree(le->label);
	gpio_device_put(le->gdev);
	kfree(le);
}

static int lineevent_release(struct inode *inode, struct file *file)
{
	lineevent_free(file->private_data);
	return 0;
}

static long lineevent_ioctl(struct file *file, unsigned int cmd,
			    unsigned long arg)
{
	struct lineevent_state *le = file->private_data;
	void __user *ip = (void __user *)arg;
	struct gpiohandle_data ghd;

	guard(srcu)(&le->gdev->srcu);

	if (!rcu_access_pointer(le->gdev->chip))
		return -ENODEV;

	/*
	 * We can get the value for an event line but not set it,
	 * because it is input by definition.
	 */
	if (cmd == GPIOHANDLE_GET_LINE_VALUES_IOCTL) {
		int val;

		memset(&ghd, 0, sizeof(ghd));

		val = gpiod_get_value_cansleep(le->desc);
		if (val < 0)
			return val;
		ghd.values[0] = val;

		if (copy_to_user(ip, &ghd, sizeof(ghd)))
			return -EFAULT;

		return 0;
	}
	return -EINVAL;
}

#ifdef CONFIG_COMPAT
static long lineevent_ioctl_compat(struct file *file, unsigned int cmd,
				   unsigned long arg)
{
	return lineevent_ioctl(file, cmd, (unsigned long)compat_ptr(arg));
}
#endif

static const struct file_operations lineevent_fileops = {
	.release = lineevent_release,
	.read = lineevent_read,
	.poll = lineevent_poll,
	.owner = THIS_MODULE,
	.llseek = noop_llseek,
	.unlocked_ioctl = lineevent_ioctl,
#ifdef CONFIG_COMPAT
	.compat_ioctl = lineevent_ioctl_compat,
#endif
};

static irqreturn_t lineevent_irq_thread(int irq, void *p)
{
	struct lineevent_state *le = p;
	struct gpioevent_data ge;
	int ret;

	/* Do not leak kernel stack to userspace */
	memset(&ge, 0, sizeof(ge));

	/*
	 * We may be running from a nested threaded interrupt in which case
	 * we didn't get the timestamp from lineevent_irq_handler().
	 */
	if (!le->timestamp)
		ge.timestamp = ktime_get_ns();
	else
		ge.timestamp = le->timestamp;

	if (le->eflags & GPIOEVENT_REQUEST_RISING_EDGE
	    && le->eflags & GPIOEVENT_REQUEST_FALLING_EDGE) {
		int level = gpiod_get_value_cansleep(le->desc);

		if (level)
			/* Emit low-to-high event */
			ge.id = GPIOEVENT_EVENT_RISING_EDGE;
		else
			/* Emit high-to-low event */
			ge.id = GPIOEVENT_EVENT_FALLING_EDGE;
	} else if (le->eflags & GPIOEVENT_REQUEST_RISING_EDGE) {
		/* Emit low-to-high event */
		ge.id = GPIOEVENT_EVENT_RISING_EDGE;
	} else if (le->eflags & GPIOEVENT_REQUEST_FALLING_EDGE) {
		/* Emit high-to-low event */
		ge.id = GPIOEVENT_EVENT_FALLING_EDGE;
	} else {
		return IRQ_NONE;
	}

	ret = kfifo_in_spinlocked_noirqsave(&le->events, &ge,
					    1, &le->wait.lock);
	if (ret)
		wake_up_poll(&le->wait, EPOLLIN);
	else
		pr_debug_ratelimited("event FIFO is full - event dropped\n");

	return IRQ_HANDLED;
}

static irqreturn_t lineevent_irq_handler(int irq, void *p)
{
	struct lineevent_state *le = p;

	/*
	 * Just store the timestamp in hardirq context so we get it as
	 * close in time as possible to the actual event.
	 */
	le->timestamp = ktime_get_ns();

	return IRQ_WAKE_THREAD;
}

static int lineevent_create(struct gpio_device *gdev, void __user *ip)
{
	struct gpioevent_request eventreq;
	struct lineevent_state *le;
	struct gpio_desc *desc;
	struct file *file;
	u32 offset;
	u32 lflags;
	u32 eflags;
	int fd;
	int ret;
	int irq, irqflags = 0;
	char *label;

	if (copy_from_user(&eventreq, ip, sizeof(eventreq)))
		return -EFAULT;

	offset = eventreq.lineoffset;
	lflags = eventreq.handleflags;
	eflags = eventreq.eventflags;

	desc = gpio_device_get_desc(gdev, offset);
	if (IS_ERR(desc))
		return PTR_ERR(desc);

	/* Return an error if a unknown flag is set */
	if ((lflags & ~GPIOHANDLE_REQUEST_VALID_FLAGS) ||
	    (eflags & ~GPIOEVENT_REQUEST_VALID_FLAGS))
		return -EINVAL;

	/* This is just wrong: we don't look for events on output lines */
	if ((lflags & GPIOHANDLE_REQUEST_OUTPUT) ||
	    (lflags & GPIOHANDLE_REQUEST_OPEN_DRAIN) ||
	    (lflags & GPIOHANDLE_REQUEST_OPEN_SOURCE))
		return -EINVAL;

	/* Only one bias flag can be set. */
	if (((lflags & GPIOHANDLE_REQUEST_BIAS_DISABLE) &&
	     (lflags & (GPIOHANDLE_REQUEST_BIAS_PULL_DOWN |
			GPIOHANDLE_REQUEST_BIAS_PULL_UP))) ||
	    ((lflags & GPIOHANDLE_REQUEST_BIAS_PULL_DOWN) &&
	     (lflags & GPIOHANDLE_REQUEST_BIAS_PULL_UP)))
		return -EINVAL;

	le = kzalloc(sizeof(*le), GFP_KERNEL);
	if (!le)
		return -ENOMEM;
	le->gdev = gpio_device_get(gdev);

	if (eventreq.consumer_label[0] != '\0') {
		/* label is only initialized if consumer_label is set */
		le->label = kstrndup(eventreq.consumer_label,
				     sizeof(eventreq.consumer_label) - 1,
				     GFP_KERNEL);
		if (!le->label) {
			ret = -ENOMEM;
			goto out_free_le;
		}
	}

	ret = gpiod_request_user(desc, le->label);
	if (ret)
		goto out_free_le;
	le->desc = desc;
	le->eflags = eflags;

	linehandle_flags_to_desc_flags(lflags, &desc->flags);

	ret = gpiod_direction_input(desc);
	if (ret)
		goto out_free_le;

	gpiod_line_state_notify(desc, GPIO_V2_LINE_CHANGED_REQUESTED);

	irq = gpiod_to_irq(desc);
	if (irq <= 0) {
		ret = -ENODEV;
		goto out_free_le;
	}

	if (eflags & GPIOEVENT_REQUEST_RISING_EDGE)
		irqflags |= test_bit(FLAG_ACTIVE_LOW, &desc->flags) ?
			IRQF_TRIGGER_FALLING : IRQF_TRIGGER_RISING;
	if (eflags & GPIOEVENT_REQUEST_FALLING_EDGE)
		irqflags |= test_bit(FLAG_ACTIVE_LOW, &desc->flags) ?
			IRQF_TRIGGER_RISING : IRQF_TRIGGER_FALLING;
	irqflags |= IRQF_ONESHOT;

	INIT_KFIFO(le->events);
	init_waitqueue_head(&le->wait);

	le->device_unregistered_nb.notifier_call = lineevent_unregistered_notify;
	ret = blocking_notifier_chain_register(&gdev->device_notifier,
					       &le->device_unregistered_nb);
	if (ret)
		goto out_free_le;

	label = make_irq_label(le->label);
	if (IS_ERR(label)) {
		ret = PTR_ERR(label);
		goto out_free_le;
	}

	/* Request a thread to read the events */
	ret = request_threaded_irq(irq,
				   lineevent_irq_handler,
				   lineevent_irq_thread,
				   irqflags,
				   label,
				   le);
	if (ret) {
		free_irq_label(label);
		goto out_free_le;
	}

	le->irq = irq;

	fd = get_unused_fd_flags(O_RDONLY | O_CLOEXEC);
	if (fd < 0) {
		ret = fd;
		goto out_free_le;
	}

	file = anon_inode_getfile("gpio-event",
				  &lineevent_fileops,
				  le,
				  O_RDONLY | O_CLOEXEC);
	if (IS_ERR(file)) {
		ret = PTR_ERR(file);
		goto out_put_unused_fd;
	}

	eventreq.fd = fd;
	if (copy_to_user(ip, &eventreq, sizeof(eventreq))) {
		/*
		 * fput() will trigger the release() callback, so do not go onto
		 * the regular error cleanup path here.
		 */
		fput(file);
		put_unused_fd(fd);
		return -EFAULT;
	}

	fd_install(fd, file);

	return 0;

out_put_unused_fd:
	put_unused_fd(fd);
out_free_le:
	lineevent_free(le);
	return ret;
}

static void gpio_v2_line_info_to_v1(struct gpio_v2_line_info *info_v2,
				    struct gpioline_info *info_v1)
{
	u64 flagsv2 = info_v2->flags;

	memcpy(info_v1->name, info_v2->name, sizeof(info_v1->name));
	memcpy(info_v1->consumer, info_v2->consumer, sizeof(info_v1->consumer));
	info_v1->line_offset = info_v2->offset;
	info_v1->flags = 0;

	if (flagsv2 & GPIO_V2_LINE_FLAG_USED)
		info_v1->flags |= GPIOLINE_FLAG_KERNEL;

	if (flagsv2 & GPIO_V2_LINE_FLAG_OUTPUT)
		info_v1->flags |= GPIOLINE_FLAG_IS_OUT;

	if (flagsv2 & GPIO_V2_LINE_FLAG_ACTIVE_LOW)
		info_v1->flags |= GPIOLINE_FLAG_ACTIVE_LOW;

	if (flagsv2 & GPIO_V2_LINE_FLAG_OPEN_DRAIN)
		info_v1->flags |= GPIOLINE_FLAG_OPEN_DRAIN;
	if (flagsv2 & GPIO_V2_LINE_FLAG_OPEN_SOURCE)
		info_v1->flags |= GPIOLINE_FLAG_OPEN_SOURCE;

	if (flagsv2 & GPIO_V2_LINE_FLAG_BIAS_PULL_UP)
		info_v1->flags |= GPIOLINE_FLAG_BIAS_PULL_UP;
	if (flagsv2 & GPIO_V2_LINE_FLAG_BIAS_PULL_DOWN)
		info_v1->flags |= GPIOLINE_FLAG_BIAS_PULL_DOWN;
	if (flagsv2 & GPIO_V2_LINE_FLAG_BIAS_DISABLED)
		info_v1->flags |= GPIOLINE_FLAG_BIAS_DISABLE;
}

static void gpio_v2_line_info_changed_to_v1(
		struct gpio_v2_line_info_changed *lic_v2,
		struct gpioline_info_changed *lic_v1)
{
	memset(lic_v1, 0, sizeof(*lic_v1));
	gpio_v2_line_info_to_v1(&lic_v2->info, &lic_v1->info);
	lic_v1->timestamp = lic_v2->timestamp_ns;
	lic_v1->event_type = lic_v2->event_type;
}

#endif /* CONFIG_GPIO_CDEV_V1 */

static void gpio_desc_to_lineinfo(struct gpio_desc *desc,
				  struct gpio_v2_line_info *info)
{
	unsigned long dflags;
	const char *label;

	CLASS(gpio_chip_guard, guard)(desc);
	if (!guard.gc)
		return;

	memset(info, 0, sizeof(*info));
	info->offset = gpio_chip_hwgpio(desc);

	if (desc->name)
		strscpy(info->name, desc->name, sizeof(info->name));

	dflags = READ_ONCE(desc->flags);

	scoped_guard(srcu, &desc->gdev->desc_srcu) {
		label = gpiod_get_label(desc);
		if (label && test_bit(FLAG_REQUESTED, &dflags))
			strscpy(info->consumer, label,
				sizeof(info->consumer));
	}

	/*
	 * Userspace only need know that the kernel is using this GPIO so it
	 * can't use it.
	 * The calculation of the used flag is slightly racy, as it may read
	 * desc, gc and pinctrl state without a lock covering all three at
	 * once.  Worst case if the line is in transition and the calculation
	 * is inconsistent then it looks to the user like they performed the
	 * read on the other side of the transition - but that can always
	 * happen.
	 * The definitive test that a line is available to userspace is to
	 * request it.
	 */
	if (test_bit(FLAG_REQUESTED, &dflags) ||
	    test_bit(FLAG_IS_HOGGED, &dflags) ||
	    test_bit(FLAG_USED_AS_IRQ, &dflags) ||
	    test_bit(FLAG_EXPORT, &dflags) ||
	    test_bit(FLAG_SYSFS, &dflags) ||
	    !gpiochip_line_is_valid(guard.gc, info->offset) ||
	    !pinctrl_gpio_can_use_line(guard.gc, info->offset))
		info->flags |= GPIO_V2_LINE_FLAG_USED;

	if (test_bit(FLAG_IS_OUT, &dflags))
		info->flags |= GPIO_V2_LINE_FLAG_OUTPUT;
	else
		info->flags |= GPIO_V2_LINE_FLAG_INPUT;

	if (test_bit(FLAG_ACTIVE_LOW, &dflags))
		info->flags |= GPIO_V2_LINE_FLAG_ACTIVE_LOW;

	if (test_bit(FLAG_OPEN_DRAIN, &dflags))
		info->flags |= GPIO_V2_LINE_FLAG_OPEN_DRAIN;
	if (test_bit(FLAG_OPEN_SOURCE, &dflags))
		info->flags |= GPIO_V2_LINE_FLAG_OPEN_SOURCE;

	if (test_bit(FLAG_BIAS_DISABLE, &dflags))
		info->flags |= GPIO_V2_LINE_FLAG_BIAS_DISABLED;
	if (test_bit(FLAG_PULL_DOWN, &dflags))
		info->flags |= GPIO_V2_LINE_FLAG_BIAS_PULL_DOWN;
	if (test_bit(FLAG_PULL_UP, &dflags))
		info->flags |= GPIO_V2_LINE_FLAG_BIAS_PULL_UP;

	if (test_bit(FLAG_EDGE_RISING, &dflags))
		info->flags |= GPIO_V2_LINE_FLAG_EDGE_RISING;
	if (test_bit(FLAG_EDGE_FALLING, &dflags))
		info->flags |= GPIO_V2_LINE_FLAG_EDGE_FALLING;

	if (test_bit(FLAG_EVENT_CLOCK_REALTIME, &dflags))
		info->flags |= GPIO_V2_LINE_FLAG_EVENT_CLOCK_REALTIME;
	else if (test_bit(FLAG_EVENT_CLOCK_HTE, &dflags))
		info->flags |= GPIO_V2_LINE_FLAG_EVENT_CLOCK_HTE;
}

struct gpio_chardev_data {
	struct gpio_device *gdev;
	wait_queue_head_t wait;
	DECLARE_KFIFO(events, struct gpio_v2_line_info_changed, 32);
	struct notifier_block lineinfo_changed_nb;
	struct notifier_block device_unregistered_nb;
	unsigned long *watched_lines;
#ifdef CONFIG_GPIO_CDEV_V1
	atomic_t watch_abi_version;
#endif
};

static int chipinfo_get(struct gpio_chardev_data *cdev, void __user *ip)
{
	struct gpio_device *gdev = cdev->gdev;
	struct gpiochip_info chipinfo;

	memset(&chipinfo, 0, sizeof(chipinfo));

	strscpy(chipinfo.name, dev_name(&gdev->dev), sizeof(chipinfo.name));
	strscpy(chipinfo.label, gdev->label, sizeof(chipinfo.label));
	chipinfo.lines = gdev->ngpio;
	if (copy_to_user(ip, &chipinfo, sizeof(chipinfo)))
		return -EFAULT;
	return 0;
}

#ifdef CONFIG_GPIO_CDEV_V1
/*
 * returns 0 if the versions match, else the previously selected ABI version
 */
static int lineinfo_ensure_abi_version(struct gpio_chardev_data *cdata,
				       unsigned int version)
{
	int abiv = atomic_cmpxchg(&cdata->watch_abi_version, 0, version);

	if (abiv == version)
		return 0;

	return abiv;
}

static int lineinfo_get_v1(struct gpio_chardev_data *cdev, void __user *ip,
			   bool watch)
{
	struct gpio_desc *desc;
	struct gpioline_info lineinfo;
	struct gpio_v2_line_info lineinfo_v2;

	if (copy_from_user(&lineinfo, ip, sizeof(lineinfo)))
		return -EFAULT;

	/* this doubles as a range check on line_offset */
	desc = gpio_device_get_desc(cdev->gdev, lineinfo.line_offset);
	if (IS_ERR(desc))
		return PTR_ERR(desc);

	if (watch) {
		if (lineinfo_ensure_abi_version(cdev, 1))
			return -EPERM;

		if (test_and_set_bit(lineinfo.line_offset, cdev->watched_lines))
			return -EBUSY;
	}

	gpio_desc_to_lineinfo(desc, &lineinfo_v2);
	gpio_v2_line_info_to_v1(&lineinfo_v2, &lineinfo);

	if (copy_to_user(ip, &lineinfo, sizeof(lineinfo))) {
		if (watch)
			clear_bit(lineinfo.line_offset, cdev->watched_lines);
		return -EFAULT;
	}

	return 0;
}
#endif

static int lineinfo_get(struct gpio_chardev_data *cdev, void __user *ip,
			bool watch)
{
	struct gpio_desc *desc;
	struct gpio_v2_line_info lineinfo;

	if (copy_from_user(&lineinfo, ip, sizeof(lineinfo)))
		return -EFAULT;

	if (memchr_inv(lineinfo.padding, 0, sizeof(lineinfo.padding)))
		return -EINVAL;

	desc = gpio_device_get_desc(cdev->gdev, lineinfo.offset);
	if (IS_ERR(desc))
		return PTR_ERR(desc);

	if (watch) {
#ifdef CONFIG_GPIO_CDEV_V1
		if (lineinfo_ensure_abi_version(cdev, 2))
			return -EPERM;
#endif
		if (test_and_set_bit(lineinfo.offset, cdev->watched_lines))
			return -EBUSY;
	}
	gpio_desc_to_lineinfo(desc, &lineinfo);
	supinfo_to_lineinfo(desc, &lineinfo);

	if (copy_to_user(ip, &lineinfo, sizeof(lineinfo))) {
		if (watch)
			clear_bit(lineinfo.offset, cdev->watched_lines);
		return -EFAULT;
	}

	return 0;
}

static int lineinfo_unwatch(struct gpio_chardev_data *cdev, void __user *ip)
{
	__u32 offset;

	if (copy_from_user(&offset, ip, sizeof(offset)))
		return -EFAULT;

	if (offset >= cdev->gdev->ngpio)
		return -EINVAL;

	if (!test_and_clear_bit(offset, cdev->watched_lines))
		return -EBUSY;

	return 0;
}

/*
 * gpio_ioctl() - ioctl handler for the GPIO chardev
 */
static long gpio_ioctl(struct file *file, unsigned int cmd, unsigned long arg)
{
	struct gpio_chardev_data *cdev = file->private_data;
	struct gpio_device *gdev = cdev->gdev;
	void __user *ip = (void __user *)arg;

	guard(srcu)(&gdev->srcu);

	/* We fail any subsequent ioctl():s when the chip is gone */
	if (!rcu_access_pointer(gdev->chip))
		return -ENODEV;

	/* Fill in the struct and pass to userspace */
	switch (cmd) {
	case GPIO_GET_CHIPINFO_IOCTL:
		return chipinfo_get(cdev, ip);
#ifdef CONFIG_GPIO_CDEV_V1
	case GPIO_GET_LINEHANDLE_IOCTL:
		return linehandle_create(gdev, ip);
	case GPIO_GET_LINEEVENT_IOCTL:
		return lineevent_create(gdev, ip);
	case GPIO_GET_LINEINFO_IOCTL:
		return lineinfo_get_v1(cdev, ip, false);
	case GPIO_GET_LINEINFO_WATCH_IOCTL:
		return lineinfo_get_v1(cdev, ip, true);
#endif /* CONFIG_GPIO_CDEV_V1 */
	case GPIO_V2_GET_LINEINFO_IOCTL:
		return lineinfo_get(cdev, ip, false);
	case GPIO_V2_GET_LINEINFO_WATCH_IOCTL:
		return lineinfo_get(cdev, ip, true);
	case GPIO_V2_GET_LINE_IOCTL:
		return linereq_create(gdev, ip);
	case GPIO_GET_LINEINFO_UNWATCH_IOCTL:
		return lineinfo_unwatch(cdev, ip);
	default:
		return -EINVAL;
	}
}

#ifdef CONFIG_COMPAT
static long gpio_ioctl_compat(struct file *file, unsigned int cmd,
			      unsigned long arg)
{
	return gpio_ioctl(file, cmd, (unsigned long)compat_ptr(arg));
}
#endif

static int lineinfo_changed_notify(struct notifier_block *nb,
				   unsigned long action, void *data)
{
	struct gpio_chardev_data *cdev =
		container_of(nb, struct gpio_chardev_data, lineinfo_changed_nb);
	struct gpio_v2_line_info_changed chg;
	struct gpio_desc *desc = data;
	int ret;

	if (!test_bit(gpio_chip_hwgpio(desc), cdev->watched_lines))
		return NOTIFY_DONE;

	memset(&chg, 0, sizeof(chg));
	chg.event_type = action;
	chg.timestamp_ns = ktime_get_ns();
	gpio_desc_to_lineinfo(desc, &chg.info);
	supinfo_to_lineinfo(desc, &chg.info);

	ret = kfifo_in_spinlocked(&cdev->events, &chg, 1, &cdev->wait.lock);
	if (ret)
		wake_up_poll(&cdev->wait, EPOLLIN);
	else
		pr_debug_ratelimited("lineinfo event FIFO is full - event dropped\n");

	return NOTIFY_OK;
}

static int gpio_device_unregistered_notify(struct notifier_block *nb,
					   unsigned long action, void *data)
{
	struct gpio_chardev_data *cdev = container_of(nb,
						      struct gpio_chardev_data,
						      device_unregistered_nb);

	wake_up_poll(&cdev->wait, EPOLLIN | EPOLLERR);

	return NOTIFY_OK;
}

static __poll_t lineinfo_watch_poll(struct file *file,
				    struct poll_table_struct *pollt)
{
	struct gpio_chardev_data *cdev = file->private_data;
	__poll_t events = 0;

	guard(srcu)(&cdev->gdev->srcu);

	if (!rcu_access_pointer(cdev->gdev->chip))
		return EPOLLHUP | EPOLLERR;

	poll_wait(file, &cdev->wait, pollt);

	if (!kfifo_is_empty_spinlocked_noirqsave(&cdev->events,
						 &cdev->wait.lock))
		events = EPOLLIN | EPOLLRDNORM;

	return events;
}

static ssize_t lineinfo_watch_read(struct file *file, char __user *buf,
				   size_t count, loff_t *off)
{
	struct gpio_chardev_data *cdev = file->private_data;
	struct gpio_v2_line_info_changed event;
	ssize_t bytes_read = 0;
	int ret;
	size_t event_size;

	guard(srcu)(&cdev->gdev->srcu);

	if (!rcu_access_pointer(cdev->gdev->chip))
		return -ENODEV;

#ifndef CONFIG_GPIO_CDEV_V1
	event_size = sizeof(struct gpio_v2_line_info_changed);
	if (count < event_size)
		return -EINVAL;
#endif

	do {
		scoped_guard(spinlock, &cdev->wait.lock) {
			if (kfifo_is_empty(&cdev->events)) {
				if (bytes_read)
					return bytes_read;

				if (file->f_flags & O_NONBLOCK)
					return -EAGAIN;

				ret = wait_event_interruptible_locked(cdev->wait,
						!kfifo_is_empty(&cdev->events));
				if (ret)
					return ret;
			}
#ifdef CONFIG_GPIO_CDEV_V1
			/* must be after kfifo check so watch_abi_version is set */
			if (atomic_read(&cdev->watch_abi_version) == 2)
				event_size = sizeof(struct gpio_v2_line_info_changed);
			else
				event_size = sizeof(struct gpioline_info_changed);
			if (count < event_size)
				return -EINVAL;
#endif
			ret = kfifo_out(&cdev->events, &event, 1);
		}
		if (ret != 1) {
			ret = -EIO;
			break;
			/* We should never get here. See lineevent_read(). */
		}

#ifdef CONFIG_GPIO_CDEV_V1
		if (event_size == sizeof(struct gpio_v2_line_info_changed)) {
			if (copy_to_user(buf + bytes_read, &event, event_size))
				return -EFAULT;
		} else {
			struct gpioline_info_changed event_v1;

			gpio_v2_line_info_changed_to_v1(&event, &event_v1);
			if (copy_to_user(buf + bytes_read, &event_v1,
					 event_size))
				return -EFAULT;
		}
#else
		if (copy_to_user(buf + bytes_read, &event, event_size))
			return -EFAULT;
#endif
		bytes_read += event_size;
	} while (count >= bytes_read + sizeof(event));

	return bytes_read;
}

/**
 * gpio_chrdev_open() - open the chardev for ioctl operations
 * @inode: inode for this chardev
 * @file: file struct for storing private data
 * Returns 0 on success
 */
static int gpio_chrdev_open(struct inode *inode, struct file *file)
{
	struct gpio_device *gdev = container_of(inode->i_cdev,
						struct gpio_device, chrdev);
	struct gpio_chardev_data *cdev;
	int ret = -ENOMEM;

	guard(srcu)(&gdev->srcu);

	/* Fail on open if the backing gpiochip is gone */
	if (!rcu_access_pointer(gdev->chip))
		return -ENODEV;

	cdev = kzalloc(sizeof(*cdev), GFP_KERNEL);
	if (!cdev)
		return -ENODEV;

	cdev->watched_lines = bitmap_zalloc(gdev->ngpio, GFP_KERNEL);
	if (!cdev->watched_lines)
		goto out_free_cdev;

	init_waitqueue_head(&cdev->wait);
	INIT_KFIFO(cdev->events);
	cdev->gdev = gpio_device_get(gdev);

	cdev->lineinfo_changed_nb.notifier_call = lineinfo_changed_notify;
	ret = blocking_notifier_chain_register(&gdev->line_state_notifier,
					       &cdev->lineinfo_changed_nb);
	if (ret)
		goto out_free_bitmap;

	cdev->device_unregistered_nb.notifier_call =
					gpio_device_unregistered_notify;
	ret = blocking_notifier_chain_register(&gdev->device_notifier,
					       &cdev->device_unregistered_nb);
	if (ret)
		goto out_unregister_line_notifier;

	file->private_data = cdev;

	ret = nonseekable_open(inode, file);
	if (ret)
		goto out_unregister_device_notifier;

	return ret;

out_unregister_device_notifier:
	blocking_notifier_chain_unregister(&gdev->device_notifier,
					   &cdev->device_unregistered_nb);
out_unregister_line_notifier:
	blocking_notifier_chain_unregister(&gdev->line_state_notifier,
					   &cdev->lineinfo_changed_nb);
out_free_bitmap:
	gpio_device_put(gdev);
	bitmap_free(cdev->watched_lines);
out_free_cdev:
	kfree(cdev);
	return ret;
}

/**
 * gpio_chrdev_release() - close chardev after ioctl operations
 * @inode: inode for this chardev
 * @file: file struct for storing private data
 * Returns 0 on success
 */
static int gpio_chrdev_release(struct inode *inode, struct file *file)
{
	struct gpio_chardev_data *cdev = file->private_data;
	struct gpio_device *gdev = cdev->gdev;

	blocking_notifier_chain_unregister(&gdev->device_notifier,
					   &cdev->device_unregistered_nb);
	blocking_notifier_chain_unregister(&gdev->line_state_notifier,
					   &cdev->lineinfo_changed_nb);
	bitmap_free(cdev->watched_lines);
	gpio_device_put(gdev);
	kfree(cdev);

	return 0;
}

static const struct file_operations gpio_fileops = {
	.release = gpio_chrdev_release,
	.open = gpio_chrdev_open,
	.poll = lineinfo_watch_poll,
	.read = lineinfo_watch_read,
	.owner = THIS_MODULE,
	.llseek = no_llseek,
	.unlocked_ioctl = gpio_ioctl,
#ifdef CONFIG_COMPAT
	.compat_ioctl = gpio_ioctl_compat,
#endif
};

int gpiolib_cdev_register(struct gpio_device *gdev, dev_t devt)
{
	struct gpio_chip *gc;
	int ret;

	cdev_init(&gdev->chrdev, &gpio_fileops);
	gdev->chrdev.owner = THIS_MODULE;
	gdev->dev.devt = MKDEV(MAJOR(devt), gdev->id);

	ret = cdev_device_add(&gdev->chrdev, &gdev->dev);
	if (ret)
		return ret;

	guard(srcu)(&gdev->srcu);
	gc = srcu_dereference(gdev->chip, &gdev->srcu);
	if (!gc)
		return -ENODEV;

	chip_dbg(gc, "added GPIO chardev (%d:%d)\n", MAJOR(devt), gdev->id);

	return 0;
}

void gpiolib_cdev_unregister(struct gpio_device *gdev)
{
	cdev_device_del(&gdev->chrdev, &gdev->dev);
	blocking_notifier_call_chain(&gdev->device_notifier, 0, NULL);
}