Bootlin logo

Elixir Cross Referencer

   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
/*
 * TI TRF7970a RFID/NFC Transceiver Driver
 *
 * Copyright (C) 2013 Texas Instruments Incorporated - http://www.ti.com
 *
 * Author: Erick Macias <emacias@ti.com>
 * Author: Felipe Balbi <balbi@ti.com>
 * Author: Mark A. Greer <mgreer@animalcreek.com>
 *
 * This program is free software: you can redistribute it and/or modify
 * it under the terms of the GNU General Public License version 2  of
 * the License as published by the Free Software Foundation.
 */

#include <linux/module.h>
#include <linux/device.h>
#include <linux/netdevice.h>
#include <linux/interrupt.h>
#include <linux/pm_runtime.h>
#include <linux/nfc.h>
#include <linux/skbuff.h>
#include <linux/delay.h>
#include <linux/gpio.h>
#include <linux/of.h>
#include <linux/of_gpio.h>
#include <linux/spi/spi.h>
#include <linux/regulator/consumer.h>

#include <net/nfc/nfc.h>
#include <net/nfc/digital.h>

/* There are 3 ways the host can communicate with the trf7970a:
 * parallel mode, SPI with Slave Select (SS) mode, and SPI without
 * SS mode.  The driver only supports the two SPI modes.
 *
 * The trf7970a is very timing sensitive and the VIN, EN2, and EN
 * pins must asserted in that order and with specific delays in between.
 * The delays used in the driver were provided by TI and have been
 * confirmed to work with this driver.  There is a bug with the current
 * version of the trf7970a that requires that EN2 remain low no matter
 * what.  If it goes high, it will generate an RF field even when in
 * passive target mode.  TI has indicated that the chip will work okay
 * when EN2 is left low.  The 'en2-rf-quirk' device tree property
 * indicates that trf7970a currently being used has the erratum and
 * that EN2 must be kept low.
 *
 * Timeouts are implemented using the delayed workqueue kernel facility.
 * Timeouts are required so things don't hang when there is no response
 * from the trf7970a (or tag).  Using this mechanism creates a race with
 * interrupts, however.  That is, an interrupt and a timeout could occur
 * closely enough together that one is blocked by the mutex while the other
 * executes.  When the timeout handler executes first and blocks the
 * interrupt handler, it will eventually set the state to IDLE so the
 * interrupt handler will check the state and exit with no harm done.
 * When the interrupt handler executes first and blocks the timeout handler,
 * the cancel_delayed_work() call will know that it didn't cancel the
 * work item (i.e., timeout) and will return zero.  That return code is
 * used by the timer handler to indicate that it should ignore the timeout
 * once its unblocked.
 *
 * Aborting an active command isn't as simple as it seems because the only
 * way to abort a command that's already been sent to the tag is so turn
 * off power to the tag.  If we do that, though, we'd have to go through
 * the entire anticollision procedure again but the digital layer doesn't
 * support that.  So, if an abort is received before trf7970a_send_cmd()
 * has sent the command to the tag, it simply returns -ECANCELED.  If the
 * command has already been sent to the tag, then the driver continues
 * normally and recieves the response data (or error) but just before
 * sending the data upstream, it frees the rx_skb and sends -ECANCELED
 * upstream instead.  If the command failed, that error will be sent
 * upstream.
 *
 * When recieving data from a tag and the interrupt status register has
 * only the SRX bit set, it means that all of the data has been received
 * (once what's in the fifo has been read).  However, depending on timing
 * an interrupt status with only the SRX bit set may not be recived.  In
 * those cases, the timeout mechanism is used to wait 20 ms in case more
 * data arrives.  After 20 ms, it is assumed that all of the data has been
 * received and the accumulated rx data is sent upstream.  The
 * 'TRF7970A_ST_WAIT_FOR_RX_DATA_CONT' state is used for this purpose
 * (i.e., it indicates that some data has been received but we're not sure
 * if there is more coming so a timeout in this state means all data has
 * been received and there isn't an error).  The delay is 20 ms since delays
 * of ~16 ms have been observed during testing.
 *
 * When transmitting a frame larger than the FIFO size (127 bytes), the
 * driver will wait 20 ms for the FIFO to drain past the low-watermark
 * and generate an interrupt.  The low-watermark set to 32 bytes so the
 * interrupt should fire after 127 - 32 = 95 bytes have been sent.  At
 * the lowest possible bit rate (6.62 kbps for 15693), it will take up
 * to ~14.35 ms so 20 ms is used for the timeout.
 *
 * Type 2 write and sector select commands respond with a 4-bit ACK or NACK.
 * Having only 4 bits in the FIFO won't normally generate an interrupt so
 * driver enables the '4_bit_RX' bit of the Special Functions register 1
 * to cause an interrupt in that case.  Leaving that bit for a read command
 * messes up the data returned so it is only enabled when the framing is
 * 'NFC_DIGITAL_FRAMING_NFCA_T2T' and the command is not a read command.
 * Unfortunately, that means that the driver has to peek into tx frames
 * when the framing is 'NFC_DIGITAL_FRAMING_NFCA_T2T'.  This is done by
 * the trf7970a_per_cmd_config() routine.
 *
 * ISO/IEC 15693 frames specify whether to use single or double sub-carrier
 * frequencies and whether to use low or high data rates in the flags byte
 * of the frame.  This means that the driver has to peek at all 15693 frames
 * to determine what speed to set the communication to.  In addition, write
 * and lock commands use the OPTION flag to indicate that an EOF must be
 * sent to the tag before it will send its response.  So the driver has to
 * examine all frames for that reason too.
 *
 * It is unclear how long to wait before sending the EOF.  According to the
 * Note under Table 1-1 in section 1.6 of
 * http://www.ti.com/lit/ug/scbu011/scbu011.pdf, that wait should be at least
 * 10 ms for TI Tag-it HF-I tags; however testing has shown that is not long
 * enough so 20 ms is used.  So the timer is set to 40 ms - 20 ms to drain
 * up to 127 bytes in the FIFO at the lowest bit rate plus another 20 ms to
 * ensure the wait is long enough before sending the EOF.  This seems to work
 * reliably.
 */

#define TRF7970A_SUPPORTED_PROTOCOLS \
		(NFC_PROTO_MIFARE_MASK | NFC_PROTO_ISO14443_MASK |	\
		 NFC_PROTO_ISO14443_B_MASK | NFC_PROTO_FELICA_MASK | \
		 NFC_PROTO_ISO15693_MASK | NFC_PROTO_NFC_DEP_MASK)

#define TRF7970A_AUTOSUSPEND_DELAY		30000 /* 30 seconds */

#define TRF7970A_RX_SKB_ALLOC_SIZE		256

#define TRF7970A_FIFO_SIZE			127

/* TX length is 3 nibbles long ==> 4KB - 1 bytes max */
#define TRF7970A_TX_MAX				(4096 - 1)

#define TRF7970A_WAIT_FOR_TX_IRQ		20
#define TRF7970A_WAIT_FOR_RX_DATA_TIMEOUT	20
#define TRF7970A_WAIT_FOR_FIFO_DRAIN_TIMEOUT	20
#define TRF7970A_WAIT_TO_ISSUE_ISO15693_EOF	40

/* Guard times for various RF technologies (in us) */
#define TRF7970A_GUARD_TIME_NFCA		5000
#define TRF7970A_GUARD_TIME_NFCB		5000
#define TRF7970A_GUARD_TIME_NFCF		20000
#define TRF7970A_GUARD_TIME_15693		1000

/* Quirks */
/* Erratum: When reading IRQ Status register on trf7970a, we must issue a
 * read continuous command for IRQ Status and Collision Position registers.
 */
#define TRF7970A_QUIRK_IRQ_STATUS_READ		BIT(0)
#define TRF7970A_QUIRK_EN2_MUST_STAY_LOW	BIT(1)
#define TRF7970A_QUIRK_T5T_RMB_EXTRA_BYTE	BIT(2)

/* Direct commands */
#define TRF7970A_CMD_IDLE			0x00
#define TRF7970A_CMD_SOFT_INIT			0x03
#define TRF7970A_CMD_RF_COLLISION		0x04
#define TRF7970A_CMD_RF_COLLISION_RESPONSE_N	0x05
#define TRF7970A_CMD_RF_COLLISION_RESPONSE_0	0x06
#define TRF7970A_CMD_FIFO_RESET			0x0f
#define TRF7970A_CMD_TRANSMIT_NO_CRC		0x10
#define TRF7970A_CMD_TRANSMIT			0x11
#define TRF7970A_CMD_DELAY_TRANSMIT_NO_CRC	0x12
#define TRF7970A_CMD_DELAY_TRANSMIT		0x13
#define TRF7970A_CMD_EOF			0x14
#define TRF7970A_CMD_CLOSE_SLOT			0x15
#define TRF7970A_CMD_BLOCK_RX			0x16
#define TRF7970A_CMD_ENABLE_RX			0x17
#define TRF7970A_CMD_TEST_INT_RF		0x18
#define TRF7970A_CMD_TEST_EXT_RF		0x19
#define TRF7970A_CMD_RX_GAIN_ADJUST		0x1a

/* Bits determining whether its a direct command or register R/W,
 * whether to use a continuous SPI transaction or not, and the actual
 * direct cmd opcode or regster address.
 */
#define TRF7970A_CMD_BIT_CTRL			BIT(7)
#define TRF7970A_CMD_BIT_RW			BIT(6)
#define TRF7970A_CMD_BIT_CONTINUOUS		BIT(5)
#define TRF7970A_CMD_BIT_OPCODE(opcode)		((opcode) & 0x1f)

/* Registers addresses */
#define TRF7970A_CHIP_STATUS_CTRL		0x00
#define TRF7970A_ISO_CTRL			0x01
#define TRF7970A_ISO14443B_TX_OPTIONS		0x02
#define TRF7970A_ISO14443A_HIGH_BITRATE_OPTIONS	0x03
#define TRF7970A_TX_TIMER_SETTING_H_BYTE	0x04
#define TRF7970A_TX_TIMER_SETTING_L_BYTE	0x05
#define TRF7970A_TX_PULSE_LENGTH_CTRL		0x06
#define TRF7970A_RX_NO_RESPONSE_WAIT		0x07
#define TRF7970A_RX_WAIT_TIME			0x08
#define TRF7970A_MODULATOR_SYS_CLK_CTRL		0x09
#define TRF7970A_RX_SPECIAL_SETTINGS		0x0a
#define TRF7970A_REG_IO_CTRL			0x0b
#define TRF7970A_IRQ_STATUS			0x0c
#define TRF7970A_COLLISION_IRQ_MASK		0x0d
#define TRF7970A_COLLISION_POSITION		0x0e
#define TRF7970A_RSSI_OSC_STATUS		0x0f
#define TRF7970A_SPECIAL_FCN_REG1		0x10
#define TRF7970A_SPECIAL_FCN_REG2		0x11
#define TRF7970A_RAM1				0x12
#define TRF7970A_RAM2				0x13
#define TRF7970A_ADJUTABLE_FIFO_IRQ_LEVELS	0x14
#define TRF7970A_NFC_LOW_FIELD_LEVEL		0x16
#define TRF7970A_NFCID1				0x17
#define TRF7970A_NFC_TARGET_LEVEL		0x18
#define TRF79070A_NFC_TARGET_PROTOCOL		0x19
#define TRF7970A_TEST_REGISTER1			0x1a
#define TRF7970A_TEST_REGISTER2			0x1b
#define TRF7970A_FIFO_STATUS			0x1c
#define TRF7970A_TX_LENGTH_BYTE1		0x1d
#define TRF7970A_TX_LENGTH_BYTE2		0x1e
#define TRF7970A_FIFO_IO_REGISTER		0x1f

/* Chip Status Control Register Bits */
#define TRF7970A_CHIP_STATUS_VRS5_3		BIT(0)
#define TRF7970A_CHIP_STATUS_REC_ON		BIT(1)
#define TRF7970A_CHIP_STATUS_AGC_ON		BIT(2)
#define TRF7970A_CHIP_STATUS_PM_ON		BIT(3)
#define TRF7970A_CHIP_STATUS_RF_PWR		BIT(4)
#define TRF7970A_CHIP_STATUS_RF_ON		BIT(5)
#define TRF7970A_CHIP_STATUS_DIRECT		BIT(6)
#define TRF7970A_CHIP_STATUS_STBY		BIT(7)

/* ISO Control Register Bits */
#define TRF7970A_ISO_CTRL_15693_SGL_1OF4_662	0x00
#define TRF7970A_ISO_CTRL_15693_SGL_1OF256_662	0x01
#define TRF7970A_ISO_CTRL_15693_SGL_1OF4_2648	0x02
#define TRF7970A_ISO_CTRL_15693_SGL_1OF256_2648	0x03
#define TRF7970A_ISO_CTRL_15693_DBL_1OF4_667a	0x04
#define TRF7970A_ISO_CTRL_15693_DBL_1OF256_667	0x05
#define TRF7970A_ISO_CTRL_15693_DBL_1OF4_2669	0x06
#define TRF7970A_ISO_CTRL_15693_DBL_1OF256_2669	0x07
#define TRF7970A_ISO_CTRL_14443A_106		0x08
#define TRF7970A_ISO_CTRL_14443A_212		0x09
#define TRF7970A_ISO_CTRL_14443A_424		0x0a
#define TRF7970A_ISO_CTRL_14443A_848		0x0b
#define TRF7970A_ISO_CTRL_14443B_106		0x0c
#define TRF7970A_ISO_CTRL_14443B_212		0x0d
#define TRF7970A_ISO_CTRL_14443B_424		0x0e
#define TRF7970A_ISO_CTRL_14443B_848		0x0f
#define TRF7970A_ISO_CTRL_FELICA_212		0x1a
#define TRF7970A_ISO_CTRL_FELICA_424		0x1b
#define TRF7970A_ISO_CTRL_NFC_NFCA_106		0x01
#define TRF7970A_ISO_CTRL_NFC_NFCF_212		0x02
#define TRF7970A_ISO_CTRL_NFC_NFCF_424		0x03
#define TRF7970A_ISO_CTRL_NFC_CE_14443A		0x00
#define TRF7970A_ISO_CTRL_NFC_CE_14443B		0x01
#define TRF7970A_ISO_CTRL_NFC_CE		BIT(2)
#define TRF7970A_ISO_CTRL_NFC_ACTIVE		BIT(3)
#define TRF7970A_ISO_CTRL_NFC_INITIATOR		BIT(4)
#define TRF7970A_ISO_CTRL_NFC_NFC_CE_MODE	BIT(5)
#define TRF7970A_ISO_CTRL_RFID			BIT(5)
#define TRF7970A_ISO_CTRL_DIR_MODE		BIT(6)
#define TRF7970A_ISO_CTRL_RX_CRC_N		BIT(7)	/* true == No CRC */

#define TRF7970A_ISO_CTRL_RFID_SPEED_MASK	0x1f

/* Modulator and SYS_CLK Control Register Bits */
#define TRF7970A_MODULATOR_DEPTH(n)		((n) & 0x7)
#define TRF7970A_MODULATOR_DEPTH_ASK10		(TRF7970A_MODULATOR_DEPTH(0))
#define TRF7970A_MODULATOR_DEPTH_OOK		(TRF7970A_MODULATOR_DEPTH(1))
#define TRF7970A_MODULATOR_DEPTH_ASK7		(TRF7970A_MODULATOR_DEPTH(2))
#define TRF7970A_MODULATOR_DEPTH_ASK8_5		(TRF7970A_MODULATOR_DEPTH(3))
#define TRF7970A_MODULATOR_DEPTH_ASK13		(TRF7970A_MODULATOR_DEPTH(4))
#define TRF7970A_MODULATOR_DEPTH_ASK16		(TRF7970A_MODULATOR_DEPTH(5))
#define TRF7970A_MODULATOR_DEPTH_ASK22		(TRF7970A_MODULATOR_DEPTH(6))
#define TRF7970A_MODULATOR_DEPTH_ASK30		(TRF7970A_MODULATOR_DEPTH(7))
#define TRF7970A_MODULATOR_EN_ANA		BIT(3)
#define TRF7970A_MODULATOR_CLK(n)		(((n) & 0x3) << 4)
#define TRF7970A_MODULATOR_CLK_DISABLED		(TRF7970A_MODULATOR_CLK(0))
#define TRF7970A_MODULATOR_CLK_3_6		(TRF7970A_MODULATOR_CLK(1))
#define TRF7970A_MODULATOR_CLK_6_13		(TRF7970A_MODULATOR_CLK(2))
#define TRF7970A_MODULATOR_CLK_13_27		(TRF7970A_MODULATOR_CLK(3))
#define TRF7970A_MODULATOR_EN_OOK		BIT(6)
#define TRF7970A_MODULATOR_27MHZ		BIT(7)

#define TRF7970A_RX_SPECIAL_SETTINGS_NO_LIM	BIT(0)
#define TRF7970A_RX_SPECIAL_SETTINGS_AGCR	BIT(1)
#define TRF7970A_RX_SPECIAL_SETTINGS_GD_0DB	(0x0 << 2)
#define TRF7970A_RX_SPECIAL_SETTINGS_GD_5DB	(0x1 << 2)
#define TRF7970A_RX_SPECIAL_SETTINGS_GD_10DB	(0x2 << 2)
#define TRF7970A_RX_SPECIAL_SETTINGS_GD_15DB	(0x3 << 2)
#define TRF7970A_RX_SPECIAL_SETTINGS_HBT	BIT(4)
#define TRF7970A_RX_SPECIAL_SETTINGS_M848	BIT(5)
#define TRF7970A_RX_SPECIAL_SETTINGS_C424	BIT(6)
#define TRF7970A_RX_SPECIAL_SETTINGS_C212	BIT(7)

#define TRF7970A_REG_IO_CTRL_VRS(v)		((v) & 0x07)
#define TRF7970A_REG_IO_CTRL_IO_LOW		BIT(5)
#define TRF7970A_REG_IO_CTRL_EN_EXT_PA		BIT(6)
#define TRF7970A_REG_IO_CTRL_AUTO_REG		BIT(7)

/* IRQ Status Register Bits */
#define TRF7970A_IRQ_STATUS_NORESP		BIT(0) /* ISO15693 only */
#define TRF7970A_IRQ_STATUS_NFC_COL_ERROR	BIT(0)
#define TRF7970A_IRQ_STATUS_COL			BIT(1)
#define TRF7970A_IRQ_STATUS_FRAMING_EOF_ERROR	BIT(2)
#define TRF7970A_IRQ_STATUS_NFC_RF		BIT(2)
#define TRF7970A_IRQ_STATUS_PARITY_ERROR	BIT(3)
#define TRF7970A_IRQ_STATUS_NFC_SDD		BIT(3)
#define TRF7970A_IRQ_STATUS_CRC_ERROR		BIT(4)
#define TRF7970A_IRQ_STATUS_NFC_PROTO_ERROR	BIT(4)
#define TRF7970A_IRQ_STATUS_FIFO		BIT(5)
#define TRF7970A_IRQ_STATUS_SRX			BIT(6)
#define TRF7970A_IRQ_STATUS_TX			BIT(7)

#define TRF7970A_IRQ_STATUS_ERROR				\
		(TRF7970A_IRQ_STATUS_COL |			\
		 TRF7970A_IRQ_STATUS_FRAMING_EOF_ERROR |	\
		 TRF7970A_IRQ_STATUS_PARITY_ERROR |		\
		 TRF7970A_IRQ_STATUS_CRC_ERROR)

#define TRF7970A_RSSI_OSC_STATUS_RSSI_MASK	(BIT(2) | BIT(1) | BIT(0))
#define TRF7970A_RSSI_OSC_STATUS_RSSI_X_MASK	(BIT(5) | BIT(4) | BIT(3))
#define TRF7970A_RSSI_OSC_STATUS_RSSI_OSC_OK	BIT(6)

#define TRF7970A_SPECIAL_FCN_REG1_COL_7_6		BIT(0)
#define TRF7970A_SPECIAL_FCN_REG1_14_ANTICOLL		BIT(1)
#define TRF7970A_SPECIAL_FCN_REG1_4_BIT_RX		BIT(2)
#define TRF7970A_SPECIAL_FCN_REG1_SP_DIR_MODE		BIT(3)
#define TRF7970A_SPECIAL_FCN_REG1_NEXT_SLOT_37US	BIT(4)
#define TRF7970A_SPECIAL_FCN_REG1_PAR43			BIT(5)

#define TRF7970A_ADJUTABLE_FIFO_IRQ_LEVELS_WLH_124	(0x0 << 2)
#define TRF7970A_ADJUTABLE_FIFO_IRQ_LEVELS_WLH_120	(0x1 << 2)
#define TRF7970A_ADJUTABLE_FIFO_IRQ_LEVELS_WLH_112	(0x2 << 2)
#define TRF7970A_ADJUTABLE_FIFO_IRQ_LEVELS_WLH_96	(0x3 << 2)
#define TRF7970A_ADJUTABLE_FIFO_IRQ_LEVELS_WLL_4	0x0
#define TRF7970A_ADJUTABLE_FIFO_IRQ_LEVELS_WLL_8	0x1
#define TRF7970A_ADJUTABLE_FIFO_IRQ_LEVELS_WLL_16	0x2
#define TRF7970A_ADJUTABLE_FIFO_IRQ_LEVELS_WLL_32	0x3

#define TRF7970A_NFC_LOW_FIELD_LEVEL_RFDET(v)	((v) & 0x07)
#define TRF7970A_NFC_LOW_FIELD_LEVEL_CLEX_DIS	BIT(7)

#define TRF7970A_NFC_TARGET_LEVEL_RFDET(v)	((v) & 0x07)
#define TRF7970A_NFC_TARGET_LEVEL_HI_RF		BIT(3)
#define TRF7970A_NFC_TARGET_LEVEL_SDD_EN	BIT(5)
#define TRF7970A_NFC_TARGET_LEVEL_LD_S_4BYTES	(0x0 << 6)
#define TRF7970A_NFC_TARGET_LEVEL_LD_S_7BYTES	(0x1 << 6)
#define TRF7970A_NFC_TARGET_LEVEL_LD_S_10BYTES	(0x2 << 6)

#define TRF79070A_NFC_TARGET_PROTOCOL_NFCBR_106		BIT(0)
#define TRF79070A_NFC_TARGET_PROTOCOL_NFCBR_212		BIT(1)
#define TRF79070A_NFC_TARGET_PROTOCOL_NFCBR_424		(BIT(0) | BIT(1))
#define TRF79070A_NFC_TARGET_PROTOCOL_PAS_14443B	BIT(2)
#define TRF79070A_NFC_TARGET_PROTOCOL_PAS_106		BIT(3)
#define TRF79070A_NFC_TARGET_PROTOCOL_FELICA		BIT(4)
#define TRF79070A_NFC_TARGET_PROTOCOL_RF_L		BIT(6)
#define TRF79070A_NFC_TARGET_PROTOCOL_RF_H		BIT(7)

#define TRF79070A_NFC_TARGET_PROTOCOL_106A		\
	 (TRF79070A_NFC_TARGET_PROTOCOL_RF_H |		\
	  TRF79070A_NFC_TARGET_PROTOCOL_RF_L |		\
	  TRF79070A_NFC_TARGET_PROTOCOL_PAS_106 |	\
	  TRF79070A_NFC_TARGET_PROTOCOL_NFCBR_106)

#define TRF79070A_NFC_TARGET_PROTOCOL_106B		\
	 (TRF79070A_NFC_TARGET_PROTOCOL_RF_H |		\
	  TRF79070A_NFC_TARGET_PROTOCOL_RF_L |		\
	  TRF79070A_NFC_TARGET_PROTOCOL_PAS_14443B |	\
	  TRF79070A_NFC_TARGET_PROTOCOL_NFCBR_106)

#define TRF79070A_NFC_TARGET_PROTOCOL_212F		\
	 (TRF79070A_NFC_TARGET_PROTOCOL_RF_H |		\
	  TRF79070A_NFC_TARGET_PROTOCOL_RF_L |		\
	  TRF79070A_NFC_TARGET_PROTOCOL_FELICA |	\
	  TRF79070A_NFC_TARGET_PROTOCOL_NFCBR_212)

#define TRF79070A_NFC_TARGET_PROTOCOL_424F		\
	 (TRF79070A_NFC_TARGET_PROTOCOL_RF_H |		\
	  TRF79070A_NFC_TARGET_PROTOCOL_RF_L |		\
	  TRF79070A_NFC_TARGET_PROTOCOL_FELICA |	\
	  TRF79070A_NFC_TARGET_PROTOCOL_NFCBR_424)

#define TRF7970A_FIFO_STATUS_OVERFLOW		BIT(7)

/* NFC (ISO/IEC 14443A) Type 2 Tag commands */
#define NFC_T2T_CMD_READ			0x30

/* ISO 15693 commands codes */
#define ISO15693_CMD_INVENTORY			0x01
#define ISO15693_CMD_READ_SINGLE_BLOCK		0x20
#define ISO15693_CMD_WRITE_SINGLE_BLOCK		0x21
#define ISO15693_CMD_LOCK_BLOCK			0x22
#define ISO15693_CMD_READ_MULTIPLE_BLOCK	0x23
#define ISO15693_CMD_WRITE_MULTIPLE_BLOCK	0x24
#define ISO15693_CMD_SELECT			0x25
#define ISO15693_CMD_RESET_TO_READY		0x26
#define ISO15693_CMD_WRITE_AFI			0x27
#define ISO15693_CMD_LOCK_AFI			0x28
#define ISO15693_CMD_WRITE_DSFID		0x29
#define ISO15693_CMD_LOCK_DSFID			0x2a
#define ISO15693_CMD_GET_SYSTEM_INFO		0x2b
#define ISO15693_CMD_GET_MULTIPLE_BLOCK_SECURITY_STATUS	0x2c

/* ISO 15693 request and response flags */
#define ISO15693_REQ_FLAG_SUB_CARRIER		BIT(0)
#define ISO15693_REQ_FLAG_DATA_RATE		BIT(1)
#define ISO15693_REQ_FLAG_INVENTORY		BIT(2)
#define ISO15693_REQ_FLAG_PROTOCOL_EXT		BIT(3)
#define ISO15693_REQ_FLAG_SELECT		BIT(4)
#define ISO15693_REQ_FLAG_AFI			BIT(4)
#define ISO15693_REQ_FLAG_ADDRESS		BIT(5)
#define ISO15693_REQ_FLAG_NB_SLOTS		BIT(5)
#define ISO15693_REQ_FLAG_OPTION		BIT(6)

#define ISO15693_REQ_FLAG_SPEED_MASK \
		(ISO15693_REQ_FLAG_SUB_CARRIER | ISO15693_REQ_FLAG_DATA_RATE)

enum trf7970a_state {
	TRF7970A_ST_PWR_OFF,
	TRF7970A_ST_RF_OFF,
	TRF7970A_ST_IDLE,
	TRF7970A_ST_IDLE_RX_BLOCKED,
	TRF7970A_ST_WAIT_FOR_TX_FIFO,
	TRF7970A_ST_WAIT_FOR_RX_DATA,
	TRF7970A_ST_WAIT_FOR_RX_DATA_CONT,
	TRF7970A_ST_WAIT_TO_ISSUE_EOF,
	TRF7970A_ST_LISTENING,
	TRF7970A_ST_LISTENING_MD,
	TRF7970A_ST_MAX
};

struct trf7970a {
	enum trf7970a_state		state;
	struct device			*dev;
	struct spi_device		*spi;
	struct regulator		*regulator;
	struct nfc_digital_dev		*ddev;
	u32				quirks;
	bool				is_initiator;
	bool				aborting;
	struct sk_buff			*tx_skb;
	struct sk_buff			*rx_skb;
	nfc_digital_cmd_complete_t	cb;
	void				*cb_arg;
	u8				chip_status_ctrl;
	u8				iso_ctrl;
	u8				iso_ctrl_tech;
	u8				modulator_sys_clk_ctrl;
	u8				special_fcn_reg1;
	unsigned int			guard_time;
	int				technology;
	int				framing;
	u8				md_rf_tech;
	u8				tx_cmd;
	bool				issue_eof;
	bool				adjust_resp_len;
	int				en2_gpio;
	int				en_gpio;
	struct mutex			lock;
	unsigned int			timeout;
	bool				ignore_timeout;
	struct delayed_work		timeout_work;
};


static int trf7970a_cmd(struct trf7970a *trf, u8 opcode)
{
	u8 cmd = TRF7970A_CMD_BIT_CTRL | TRF7970A_CMD_BIT_OPCODE(opcode);
	int ret;

	dev_dbg(trf->dev, "cmd: 0x%x\n", cmd);

	ret = spi_write(trf->spi, &cmd, 1);
	if (ret)
		dev_err(trf->dev, "%s - cmd: 0x%x, ret: %d\n", __func__, cmd,
				ret);
	return ret;
}

static int trf7970a_read(struct trf7970a *trf, u8 reg, u8 *val)
{
	u8 addr = TRF7970A_CMD_BIT_RW | reg;
	int ret;

	ret = spi_write_then_read(trf->spi, &addr, 1, val, 1);
	if (ret)
		dev_err(trf->dev, "%s - addr: 0x%x, ret: %d\n", __func__, addr,
				ret);

	dev_dbg(trf->dev, "read(0x%x): 0x%x\n", addr, *val);

	return ret;
}

static int trf7970a_read_cont(struct trf7970a *trf, u8 reg, u8 *buf, size_t len)
{
	u8 addr = reg | TRF7970A_CMD_BIT_RW | TRF7970A_CMD_BIT_CONTINUOUS;
	struct spi_transfer t[2];
	struct spi_message m;
	int ret;

	dev_dbg(trf->dev, "read_cont(0x%x, %zd)\n", addr, len);

	spi_message_init(&m);

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

	t[0].tx_buf = &addr;
	t[0].len = sizeof(addr);
	spi_message_add_tail(&t[0], &m);

	t[1].rx_buf = buf;
	t[1].len = len;
	spi_message_add_tail(&t[1], &m);

	ret = spi_sync(trf->spi, &m);
	if (ret)
		dev_err(trf->dev, "%s - addr: 0x%x, ret: %d\n", __func__, addr,
				ret);
	return ret;
}

static int trf7970a_write(struct trf7970a *trf, u8 reg, u8 val)
{
	u8 buf[2] = { reg, val };
	int ret;

	dev_dbg(trf->dev, "write(0x%x): 0x%x\n", reg, val);

	ret = spi_write(trf->spi, buf, 2);
	if (ret)
		dev_err(trf->dev, "%s - write: 0x%x 0x%x, ret: %d\n", __func__,
				buf[0], buf[1], ret);

	return ret;
}

static int trf7970a_read_irqstatus(struct trf7970a *trf, u8 *status)
{
	int ret;
	u8 buf[2];
	u8 addr;

	addr = TRF7970A_IRQ_STATUS | TRF7970A_CMD_BIT_RW;

	if (trf->quirks & TRF7970A_QUIRK_IRQ_STATUS_READ) {
		addr |= TRF7970A_CMD_BIT_CONTINUOUS;
		ret = spi_write_then_read(trf->spi, &addr, 1, buf, 2);
	} else {
		ret = spi_write_then_read(trf->spi, &addr, 1, buf, 1);
	}

	if (ret)
		dev_err(trf->dev, "%s - irqstatus: Status read failed: %d\n",
				__func__, ret);
	else
		*status = buf[0];

	return ret;
}

static int trf7970a_read_target_proto(struct trf7970a *trf, u8 *target_proto)
{
	int ret;
	u8 buf[2];
	u8 addr;

	addr = TRF79070A_NFC_TARGET_PROTOCOL | TRF7970A_CMD_BIT_RW |
		TRF7970A_CMD_BIT_CONTINUOUS;

	ret = spi_write_then_read(trf->spi, &addr, 1, buf, 2);
	if (ret)
		dev_err(trf->dev, "%s - target_proto: Read failed: %d\n",
				__func__, ret);
	else
		*target_proto = buf[0];

	return ret;
}

static int trf7970a_mode_detect(struct trf7970a *trf, u8 *rf_tech)
{
	int ret;
	u8 target_proto, tech;

	ret = trf7970a_read_target_proto(trf, &target_proto);
	if (ret)
		return ret;

	switch (target_proto) {
	case TRF79070A_NFC_TARGET_PROTOCOL_106A:
		tech = NFC_DIGITAL_RF_TECH_106A;
		break;
	case TRF79070A_NFC_TARGET_PROTOCOL_106B:
		tech = NFC_DIGITAL_RF_TECH_106B;
		break;
	case TRF79070A_NFC_TARGET_PROTOCOL_212F:
		tech = NFC_DIGITAL_RF_TECH_212F;
		break;
	case TRF79070A_NFC_TARGET_PROTOCOL_424F:
		tech = NFC_DIGITAL_RF_TECH_424F;
		break;
	default:
		dev_dbg(trf->dev, "%s - mode_detect: target_proto: 0x%x\n",
				__func__, target_proto);
		return -EIO;
	}

	*rf_tech = tech;

	return ret;
}

static void trf7970a_send_upstream(struct trf7970a *trf)
{
	dev_kfree_skb_any(trf->tx_skb);
	trf->tx_skb = NULL;

	if (trf->rx_skb && !IS_ERR(trf->rx_skb) && !trf->aborting)
		print_hex_dump_debug("trf7970a rx data: ", DUMP_PREFIX_NONE,
				16, 1, trf->rx_skb->data, trf->rx_skb->len,
				false);

	trf->state = TRF7970A_ST_IDLE;

	if (trf->aborting) {
		dev_dbg(trf->dev, "Abort process complete\n");

		if (!IS_ERR(trf->rx_skb)) {
			kfree_skb(trf->rx_skb);
			trf->rx_skb = ERR_PTR(-ECANCELED);
		}

		trf->aborting = false;
	}

	if (trf->adjust_resp_len) {
		if (trf->rx_skb)
			skb_trim(trf->rx_skb, trf->rx_skb->len - 1);

		trf->adjust_resp_len = false;
	}

	trf->cb(trf->ddev, trf->cb_arg, trf->rx_skb);

	trf->rx_skb = NULL;
}

static void trf7970a_send_err_upstream(struct trf7970a *trf, int errno)
{
	dev_dbg(trf->dev, "Error - state: %d, errno: %d\n", trf->state, errno);

	cancel_delayed_work(&trf->timeout_work);

	kfree_skb(trf->rx_skb);
	trf->rx_skb = ERR_PTR(errno);

	trf7970a_send_upstream(trf);
}

static int trf7970a_transmit(struct trf7970a *trf, struct sk_buff *skb,
		unsigned int len, u8 *prefix, unsigned int prefix_len)
{
	struct spi_transfer t[2];
	struct spi_message m;
	unsigned int timeout;
	int ret;

	print_hex_dump_debug("trf7970a tx data: ", DUMP_PREFIX_NONE,
			16, 1, skb->data, len, false);

	spi_message_init(&m);

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

	t[0].tx_buf = prefix;
	t[0].len = prefix_len;
	spi_message_add_tail(&t[0], &m);

	t[1].tx_buf = skb->data;
	t[1].len = len;
	spi_message_add_tail(&t[1], &m);

	ret = spi_sync(trf->spi, &m);
	if (ret) {
		dev_err(trf->dev, "%s - Can't send tx data: %d\n", __func__,
				ret);
		return ret;
	}

	skb_pull(skb, len);

	if (skb->len > 0) {
		trf->state = TRF7970A_ST_WAIT_FOR_TX_FIFO;
		timeout = TRF7970A_WAIT_FOR_FIFO_DRAIN_TIMEOUT;
	} else {
		if (trf->issue_eof) {
			trf->state = TRF7970A_ST_WAIT_TO_ISSUE_EOF;
			timeout = TRF7970A_WAIT_TO_ISSUE_ISO15693_EOF;
		} else {
			trf->state = TRF7970A_ST_WAIT_FOR_RX_DATA;

			if (!trf->timeout)
				timeout = TRF7970A_WAIT_FOR_TX_IRQ;
			else
				timeout = trf->timeout;
		}
	}

	dev_dbg(trf->dev, "Setting timeout for %d ms, state: %d\n", timeout,
			trf->state);

	schedule_delayed_work(&trf->timeout_work, msecs_to_jiffies(timeout));

	return 0;
}

static void trf7970a_fill_fifo(struct trf7970a *trf)
{
	struct sk_buff *skb = trf->tx_skb;
	unsigned int len;
	int ret;
	u8 fifo_bytes;
	u8 prefix;

	ret = trf7970a_read(trf, TRF7970A_FIFO_STATUS, &fifo_bytes);
	if (ret) {
		trf7970a_send_err_upstream(trf, ret);
		return;
	}

	dev_dbg(trf->dev, "Filling FIFO - fifo_bytes: 0x%x\n", fifo_bytes);

	fifo_bytes &= ~TRF7970A_FIFO_STATUS_OVERFLOW;

	/* Calculate how much more data can be written to the fifo */
	len = TRF7970A_FIFO_SIZE - fifo_bytes;
	if (!len) {
		schedule_delayed_work(&trf->timeout_work,
			msecs_to_jiffies(TRF7970A_WAIT_FOR_FIFO_DRAIN_TIMEOUT));
		return;
	}

	len = min(skb->len, len);

	prefix = TRF7970A_CMD_BIT_CONTINUOUS | TRF7970A_FIFO_IO_REGISTER;

	ret = trf7970a_transmit(trf, skb, len, &prefix, sizeof(prefix));
	if (ret)
		trf7970a_send_err_upstream(trf, ret);
}

static void trf7970a_drain_fifo(struct trf7970a *trf, u8 status)
{
	struct sk_buff *skb = trf->rx_skb;
	int ret;
	u8 fifo_bytes;

	if (status & TRF7970A_IRQ_STATUS_ERROR) {
		trf7970a_send_err_upstream(trf, -EIO);
		return;
	}

	ret = trf7970a_read(trf, TRF7970A_FIFO_STATUS, &fifo_bytes);
	if (ret) {
		trf7970a_send_err_upstream(trf, ret);
		return;
	}

	dev_dbg(trf->dev, "Draining FIFO - fifo_bytes: 0x%x\n", fifo_bytes);

	fifo_bytes &= ~TRF7970A_FIFO_STATUS_OVERFLOW;

	if (!fifo_bytes)
		goto no_rx_data;

	if (fifo_bytes > skb_tailroom(skb)) {
		skb = skb_copy_expand(skb, skb_headroom(skb),
				max_t(int, fifo_bytes,
					TRF7970A_RX_SKB_ALLOC_SIZE),
				GFP_KERNEL);
		if (!skb) {
			trf7970a_send_err_upstream(trf, -ENOMEM);
			return;
		}

		kfree_skb(trf->rx_skb);
		trf->rx_skb = skb;
	}

	ret = trf7970a_read_cont(trf, TRF7970A_FIFO_IO_REGISTER,
			skb_put(skb, fifo_bytes), fifo_bytes);
	if (ret) {
		trf7970a_send_err_upstream(trf, ret);
		return;
	}

	/* If received Type 2 ACK/NACK, shift right 4 bits and pass up */
	if ((trf->framing == NFC_DIGITAL_FRAMING_NFCA_T2T) && (skb->len == 1) &&
			(trf->special_fcn_reg1 ==
				 TRF7970A_SPECIAL_FCN_REG1_4_BIT_RX)) {
		skb->data[0] >>= 4;
		status = TRF7970A_IRQ_STATUS_SRX;
	} else {
		trf->state = TRF7970A_ST_WAIT_FOR_RX_DATA_CONT;

		ret = trf7970a_read(trf, TRF7970A_FIFO_STATUS, &fifo_bytes);
		if (ret) {
			trf7970a_send_err_upstream(trf, ret);
			return;
		}

		fifo_bytes &= ~TRF7970A_FIFO_STATUS_OVERFLOW;

		/* If there are bytes in the FIFO, set status to '0' so
		 * the if stmt below doesn't fire and the driver will wait
		 * for the trf7970a to generate another RX interrupt.
		 */
		if (fifo_bytes)
			status = 0;
	}

no_rx_data:
	if (status == TRF7970A_IRQ_STATUS_SRX) { /* Receive complete */
		trf7970a_send_upstream(trf);
		return;
	}

	dev_dbg(trf->dev, "Setting timeout for %d ms\n",
			TRF7970A_WAIT_FOR_RX_DATA_TIMEOUT);

	schedule_delayed_work(&trf->timeout_work,
			msecs_to_jiffies(TRF7970A_WAIT_FOR_RX_DATA_TIMEOUT));
}

static irqreturn_t trf7970a_irq(int irq, void *dev_id)
{
	struct trf7970a *trf = dev_id;
	int ret;
	u8 status, fifo_bytes, iso_ctrl;

	mutex_lock(&trf->lock);

	if (trf->state == TRF7970A_ST_RF_OFF) {
		mutex_unlock(&trf->lock);
		return IRQ_NONE;
	}

	ret = trf7970a_read_irqstatus(trf, &status);
	if (ret) {
		mutex_unlock(&trf->lock);
		return IRQ_NONE;
	}

	dev_dbg(trf->dev, "IRQ - state: %d, status: 0x%x\n", trf->state,
			status);

	if (!status) {
		mutex_unlock(&trf->lock);
		return IRQ_NONE;
	}

	switch (trf->state) {
	case TRF7970A_ST_IDLE:
	case TRF7970A_ST_IDLE_RX_BLOCKED:
		/* If initiator and getting interrupts caused by RF noise,
		 * turn off the receiver to avoid unnecessary interrupts.
		 * It will be turned back on in trf7970a_send_cmd() when
		 * the next command is issued.
		 */
		if (trf->is_initiator && (status & TRF7970A_IRQ_STATUS_ERROR)) {
			trf7970a_cmd(trf, TRF7970A_CMD_BLOCK_RX);
			trf->state = TRF7970A_ST_IDLE_RX_BLOCKED;
		}

		trf7970a_cmd(trf, TRF7970A_CMD_FIFO_RESET);
		break;
	case TRF7970A_ST_WAIT_FOR_TX_FIFO:
		if (status & TRF7970A_IRQ_STATUS_TX) {
			trf->ignore_timeout =
				!cancel_delayed_work(&trf->timeout_work);
			trf7970a_fill_fifo(trf);
		} else {
			trf7970a_send_err_upstream(trf, -EIO);
		}
		break;
	case TRF7970A_ST_WAIT_FOR_RX_DATA:
	case TRF7970A_ST_WAIT_FOR_RX_DATA_CONT:
		if (status & TRF7970A_IRQ_STATUS_SRX) {
			trf->ignore_timeout =
				!cancel_delayed_work(&trf->timeout_work);
			trf7970a_drain_fifo(trf, status);
		} else if (status & TRF7970A_IRQ_STATUS_FIFO) {
			ret = trf7970a_read(trf, TRF7970A_FIFO_STATUS,
					&fifo_bytes);

			fifo_bytes &= ~TRF7970A_FIFO_STATUS_OVERFLOW;

			if (ret)
				trf7970a_send_err_upstream(trf, ret);
			else if (!fifo_bytes)
				trf7970a_cmd(trf, TRF7970A_CMD_FIFO_RESET);
		} else if ((status == TRF7970A_IRQ_STATUS_TX) ||
				(!trf->is_initiator &&
				 (status == (TRF7970A_IRQ_STATUS_TX |
					     TRF7970A_IRQ_STATUS_NFC_RF)))) {
			trf7970a_cmd(trf, TRF7970A_CMD_FIFO_RESET);

			if (!trf->timeout) {
				trf->ignore_timeout = !cancel_delayed_work(
						&trf->timeout_work);
				trf->rx_skb = ERR_PTR(0);
				trf7970a_send_upstream(trf);
				break;
			}

			if (trf->is_initiator)
				break;

			iso_ctrl = trf->iso_ctrl;

			switch (trf->framing) {
			case NFC_DIGITAL_FRAMING_NFCA_STANDARD:
				trf->tx_cmd = TRF7970A_CMD_TRANSMIT_NO_CRC;
				iso_ctrl |= TRF7970A_ISO_CTRL_RX_CRC_N;
				trf->iso_ctrl = 0xff; /* Force ISO_CTRL write */
				break;
			case NFC_DIGITAL_FRAMING_NFCA_STANDARD_WITH_CRC_A:
				trf->tx_cmd = TRF7970A_CMD_TRANSMIT;
				iso_ctrl &= ~TRF7970A_ISO_CTRL_RX_CRC_N;
				trf->iso_ctrl = 0xff; /* Force ISO_CTRL write */
				break;
			case NFC_DIGITAL_FRAMING_NFCA_ANTICOL_COMPLETE:
				ret = trf7970a_write(trf,
					TRF7970A_SPECIAL_FCN_REG1,
					TRF7970A_SPECIAL_FCN_REG1_14_ANTICOLL);
				if (ret)
					goto err_unlock_exit;

				trf->special_fcn_reg1 =
					TRF7970A_SPECIAL_FCN_REG1_14_ANTICOLL;
				break;
			default:
				break;
			}

			if (iso_ctrl != trf->iso_ctrl) {
				ret = trf7970a_write(trf, TRF7970A_ISO_CTRL,
						iso_ctrl);
				if (ret)
					goto err_unlock_exit;

				trf->iso_ctrl = iso_ctrl;
			}
		} else {
			trf7970a_send_err_upstream(trf, -EIO);
		}
		break;
	case TRF7970A_ST_WAIT_TO_ISSUE_EOF:
		if (status != TRF7970A_IRQ_STATUS_TX)
			trf7970a_send_err_upstream(trf, -EIO);
		break;
	case TRF7970A_ST_LISTENING:
		if (status & TRF7970A_IRQ_STATUS_SRX) {
			trf->ignore_timeout =
				!cancel_delayed_work(&trf->timeout_work);
			trf7970a_drain_fifo(trf, status);
		} else if (!(status & TRF7970A_IRQ_STATUS_NFC_RF)) {
			trf7970a_send_err_upstream(trf, -EIO);
		}
		break;
	case TRF7970A_ST_LISTENING_MD:
		if (status & TRF7970A_IRQ_STATUS_SRX) {
			trf->ignore_timeout =
				!cancel_delayed_work(&trf->timeout_work);

			ret = trf7970a_mode_detect(trf, &trf->md_rf_tech);
			if (ret) {
				trf7970a_send_err_upstream(trf, ret);
			} else {
				trf->state = TRF7970A_ST_LISTENING;
				trf7970a_drain_fifo(trf, status);
			}
		} else if (!(status & TRF7970A_IRQ_STATUS_NFC_RF)) {
			trf7970a_send_err_upstream(trf, -EIO);
		}
		break;
	default:
		dev_err(trf->dev, "%s - Driver in invalid state: %d\n",
				__func__, trf->state);
	}

err_unlock_exit:
	mutex_unlock(&trf->lock);
	return IRQ_HANDLED;
}

static void trf7970a_issue_eof(struct trf7970a *trf)
{
	int ret;

	dev_dbg(trf->dev, "Issuing EOF\n");

	ret = trf7970a_cmd(trf, TRF7970A_CMD_FIFO_RESET);
	if (ret)
		trf7970a_send_err_upstream(trf, ret);

	ret = trf7970a_cmd(trf, TRF7970A_CMD_EOF);
	if (ret)
		trf7970a_send_err_upstream(trf, ret);

	trf->state = TRF7970A_ST_WAIT_FOR_RX_DATA;

	dev_dbg(trf->dev, "Setting timeout for %d ms, state: %d\n",
			trf->timeout, trf->state);

	schedule_delayed_work(&trf->timeout_work,
			msecs_to_jiffies(trf->timeout));
}

static void trf7970a_timeout_work_handler(struct work_struct *work)
{
	struct trf7970a *trf = container_of(work, struct trf7970a,
			timeout_work.work);

	dev_dbg(trf->dev, "Timeout - state: %d, ignore_timeout: %d\n",
			trf->state, trf->ignore_timeout);

	mutex_lock(&trf->lock);

	if (trf->ignore_timeout)
		trf->ignore_timeout = false;
	else if (trf->state == TRF7970A_ST_WAIT_FOR_RX_DATA_CONT)
		trf7970a_drain_fifo(trf, TRF7970A_IRQ_STATUS_SRX);
	else if (trf->state == TRF7970A_ST_WAIT_TO_ISSUE_EOF)
		trf7970a_issue_eof(trf);
	else
		trf7970a_send_err_upstream(trf, -ETIMEDOUT);

	mutex_unlock(&trf->lock);
}

static int trf7970a_init(struct trf7970a *trf)
{
	int ret;

	dev_dbg(trf->dev, "Initializing device - state: %d\n", trf->state);

	ret = trf7970a_cmd(trf, TRF7970A_CMD_SOFT_INIT);
	if (ret)
		goto err_out;

	ret = trf7970a_cmd(trf, TRF7970A_CMD_IDLE);
	if (ret)
		goto err_out;

	ret = trf7970a_write(trf, TRF7970A_NFC_TARGET_LEVEL, 0);
	if (ret)
		goto err_out;

	usleep_range(1000, 2000);

	trf->chip_status_ctrl &= ~TRF7970A_CHIP_STATUS_RF_ON;

	ret = trf7970a_write(trf, TRF7970A_MODULATOR_SYS_CLK_CTRL, 0);
	if (ret)
		goto err_out;

	trf->modulator_sys_clk_ctrl = 0;

	ret = trf7970a_write(trf, TRF7970A_ADJUTABLE_FIFO_IRQ_LEVELS,
			TRF7970A_ADJUTABLE_FIFO_IRQ_LEVELS_WLH_96 |
			TRF7970A_ADJUTABLE_FIFO_IRQ_LEVELS_WLL_32);
	if (ret)
		goto err_out;

	ret = trf7970a_write(trf, TRF7970A_SPECIAL_FCN_REG1, 0);
	if (ret)
		goto err_out;

	trf->special_fcn_reg1 = 0;

	trf->iso_ctrl = 0xff;
	return 0;

err_out:
	dev_dbg(trf->dev, "Couldn't init device: %d\n", ret);
	return ret;
}

static void trf7970a_switch_rf_off(struct trf7970a *trf)
{
	if ((trf->state == TRF7970A_ST_PWR_OFF) ||
			(trf->state == TRF7970A_ST_RF_OFF))
		return;

	dev_dbg(trf->dev, "Switching rf off\n");

	trf->chip_status_ctrl &= ~TRF7970A_CHIP_STATUS_RF_ON;

	trf7970a_write(trf, TRF7970A_CHIP_STATUS_CTRL, trf->chip_status_ctrl);

	trf->aborting = false;
	trf->state = TRF7970A_ST_RF_OFF;

	pm_runtime_mark_last_busy(trf->dev);
	pm_runtime_put_autosuspend(trf->dev);
}

static int trf7970a_switch_rf_on(struct trf7970a *trf)
{
	int ret;

	dev_dbg(trf->dev, "Switching rf on\n");

	pm_runtime_get_sync(trf->dev);

	if (trf->state != TRF7970A_ST_RF_OFF) { /* Power on, RF off */
		dev_err(trf->dev, "%s - Incorrect state: %d\n", __func__,
				trf->state);
		return -EINVAL;
	}

	ret = trf7970a_init(trf);
	if (ret) {
		dev_err(trf->dev, "%s - Can't initialize: %d\n", __func__, ret);
		return ret;
	}

	trf->state = TRF7970A_ST_IDLE;

	return 0;
}

static int trf7970a_switch_rf(struct nfc_digital_dev *ddev, bool on)
{
	struct trf7970a *trf = nfc_digital_get_drvdata(ddev);
	int ret = 0;

	dev_dbg(trf->dev, "Switching RF - state: %d, on: %d\n", trf->state, on);

	mutex_lock(&trf->lock);

	if (on) {
		switch (trf->state) {
		case TRF7970A_ST_PWR_OFF:
		case TRF7970A_ST_RF_OFF:
			ret = trf7970a_switch_rf_on(trf);
			break;
		case TRF7970A_ST_IDLE:
		case TRF7970A_ST_IDLE_RX_BLOCKED:
			break;
		default:
			dev_err(trf->dev, "%s - Invalid request: %d %d\n",
					__func__, trf->state, on);
			trf7970a_switch_rf_off(trf);
			ret = -EINVAL;
		}
	} else {
		switch (trf->state) {
		case TRF7970A_ST_PWR_OFF:
		case TRF7970A_ST_RF_OFF:
			break;
		default:
			dev_err(trf->dev, "%s - Invalid request: %d %d\n",
					__func__, trf->state, on);
			ret = -EINVAL;
			/* FALLTHROUGH */
		case TRF7970A_ST_IDLE:
		case TRF7970A_ST_IDLE_RX_BLOCKED:
		case TRF7970A_ST_WAIT_FOR_RX_DATA:
		case TRF7970A_ST_WAIT_FOR_RX_DATA_CONT:
			trf7970a_switch_rf_off(trf);
		}
	}

	mutex_unlock(&trf->lock);
	return ret;
}

static int trf7970a_in_config_rf_tech(struct trf7970a *trf, int tech)
{
	int ret = 0;

	dev_dbg(trf->dev, "rf technology: %d\n", tech);

	switch (tech) {
	case NFC_DIGITAL_RF_TECH_106A:
		trf->iso_ctrl_tech = TRF7970A_ISO_CTRL_14443A_106;
		trf->modulator_sys_clk_ctrl = TRF7970A_MODULATOR_DEPTH_OOK;
		trf->guard_time = TRF7970A_GUARD_TIME_NFCA;
		break;
	case NFC_DIGITAL_RF_TECH_106B:
		trf->iso_ctrl_tech = TRF7970A_ISO_CTRL_14443B_106;
		trf->modulator_sys_clk_ctrl = TRF7970A_MODULATOR_DEPTH_ASK10;
		trf->guard_time = TRF7970A_GUARD_TIME_NFCB;
		break;
	case NFC_DIGITAL_RF_TECH_212F:
		trf->iso_ctrl_tech = TRF7970A_ISO_CTRL_FELICA_212;
		trf->modulator_sys_clk_ctrl = TRF7970A_MODULATOR_DEPTH_ASK10;
		trf->guard_time = TRF7970A_GUARD_TIME_NFCF;
		break;
	case NFC_DIGITAL_RF_TECH_424F:
		trf->iso_ctrl_tech = TRF7970A_ISO_CTRL_FELICA_424;
		trf->modulator_sys_clk_ctrl = TRF7970A_MODULATOR_DEPTH_ASK10;
		trf->guard_time = TRF7970A_GUARD_TIME_NFCF;
		break;
	case NFC_DIGITAL_RF_TECH_ISO15693:
		trf->iso_ctrl_tech = TRF7970A_ISO_CTRL_15693_SGL_1OF4_2648;
		trf->modulator_sys_clk_ctrl = TRF7970A_MODULATOR_DEPTH_OOK;
		trf->guard_time = TRF7970A_GUARD_TIME_15693;
		break;
	default:
		dev_dbg(trf->dev, "Unsupported rf technology: %d\n", tech);
		return -EINVAL;
	}

	trf->technology = tech;

	/* If in initiator mode and not changing the RF tech due to a
	 * PSL sequence (indicated by 'trf->iso_ctrl == 0xff' from
	 * trf7970a_init()), clear the NFC Target Detection Level register
	 * due to erratum.
	 */
	if (trf->iso_ctrl == 0xff)
		ret = trf7970a_write(trf, TRF7970A_NFC_TARGET_LEVEL, 0);

	return ret;
}

static int trf7970a_is_rf_field(struct trf7970a *trf, bool *is_rf_field)
{
	int ret;
	u8 rssi;

	ret = trf7970a_write(trf, TRF7970A_CHIP_STATUS_CTRL,
			trf->chip_status_ctrl | TRF7970A_CHIP_STATUS_REC_ON);
	if (ret)
		return ret;

	ret = trf7970a_cmd(trf, TRF7970A_CMD_TEST_EXT_RF);
	if (ret)
		return ret;

	usleep_range(50, 60);

	ret = trf7970a_read(trf, TRF7970A_RSSI_OSC_STATUS, &rssi);
	if (ret)
		return ret;

	ret = trf7970a_write(trf, TRF7970A_CHIP_STATUS_CTRL,
			trf->chip_status_ctrl);
	if (ret)
		return ret;

	if (rssi & TRF7970A_RSSI_OSC_STATUS_RSSI_MASK)
		*is_rf_field = true;
	else
		*is_rf_field = false;

	return 0;
}

static int trf7970a_in_config_framing(struct trf7970a *trf, int framing)
{
	u8 iso_ctrl = trf->iso_ctrl_tech;
	bool is_rf_field = false;
	int ret;

	dev_dbg(trf->dev, "framing: %d\n", framing);

	switch (framing) {
	case NFC_DIGITAL_FRAMING_NFCA_SHORT:
	case NFC_DIGITAL_FRAMING_NFCA_STANDARD:
		trf->tx_cmd = TRF7970A_CMD_TRANSMIT_NO_CRC;
		iso_ctrl |= TRF7970A_ISO_CTRL_RX_CRC_N;
		break;
	case NFC_DIGITAL_FRAMING_NFCA_STANDARD_WITH_CRC_A:
	case NFC_DIGITAL_FRAMING_NFCA_T4T:
	case NFC_DIGITAL_FRAMING_NFCB:
	case NFC_DIGITAL_FRAMING_NFCB_T4T:
	case NFC_DIGITAL_FRAMING_NFCF:
	case NFC_DIGITAL_FRAMING_NFCF_T3T:
	case NFC_DIGITAL_FRAMING_ISO15693_INVENTORY:
	case NFC_DIGITAL_FRAMING_ISO15693_T5T:
	case NFC_DIGITAL_FRAMING_NFCA_NFC_DEP:
	case NFC_DIGITAL_FRAMING_NFCF_NFC_DEP:
		trf->tx_cmd = TRF7970A_CMD_TRANSMIT;
		iso_ctrl &= ~TRF7970A_ISO_CTRL_RX_CRC_N;
		break;
	case NFC_DIGITAL_FRAMING_NFCA_T2T:
		trf->tx_cmd = TRF7970A_CMD_TRANSMIT;
		iso_ctrl |= TRF7970A_ISO_CTRL_RX_CRC_N;
		break;
	default:
		dev_dbg(trf->dev, "Unsupported Framing: %d\n", framing);
		return -EINVAL;
	}

	trf->framing = framing;

	if (!(trf->chip_status_ctrl & TRF7970A_CHIP_STATUS_RF_ON)) {
		ret = trf7970a_is_rf_field(trf, &is_rf_field);
		if (ret)
			return ret;

		if (is_rf_field)
			return -EBUSY;
	}

	if (iso_ctrl != trf->iso_ctrl) {
		ret = trf7970a_write(trf, TRF7970A_ISO_CTRL, iso_ctrl);
		if (ret)
			return ret;

		trf->iso_ctrl = iso_ctrl;

		ret = trf7970a_write(trf, TRF7970A_MODULATOR_SYS_CLK_CTRL,
				trf->modulator_sys_clk_ctrl);
		if (ret)
			return ret;
	}

	if (!(trf->chip_status_ctrl & TRF7970A_CHIP_STATUS_RF_ON)) {
		ret = trf7970a_write(trf, TRF7970A_CHIP_STATUS_CTRL,
				trf->chip_status_ctrl |
					TRF7970A_CHIP_STATUS_RF_ON);
		if (ret)
			return ret;

		trf->chip_status_ctrl |= TRF7970A_CHIP_STATUS_RF_ON;

		usleep_range(trf->guard_time, trf->guard_time + 1000);
	}

	return 0;
}

static int trf7970a_in_configure_hw(struct nfc_digital_dev *ddev, int type,
		int param)
{
	struct trf7970a *trf = nfc_digital_get_drvdata(ddev);
	int ret;

	dev_dbg(trf->dev, "Configure hw - type: %d, param: %d\n", type, param);

	mutex_lock(&trf->lock);

	trf->is_initiator = true;

	if ((trf->state == TRF7970A_ST_PWR_OFF) ||
			(trf->state == TRF7970A_ST_RF_OFF)) {
		ret = trf7970a_switch_rf_on(trf);
		if (ret)
			goto err_unlock;
	}

	switch (type) {
	case NFC_DIGITAL_CONFIG_RF_TECH:
		ret = trf7970a_in_config_rf_tech(trf, param);
		break;
	case NFC_DIGITAL_CONFIG_FRAMING:
		ret = trf7970a_in_config_framing(trf, param);
		break;
	default:
		dev_dbg(trf->dev, "Unknown type: %d\n", type);
		ret = -EINVAL;
	}

err_unlock:
	mutex_unlock(&trf->lock);
	return ret;
}

static int trf7970a_is_iso15693_write_or_lock(u8 cmd)
{
	switch (cmd) {
	case ISO15693_CMD_WRITE_SINGLE_BLOCK:
	case ISO15693_CMD_LOCK_BLOCK:
	case ISO15693_CMD_WRITE_MULTIPLE_BLOCK:
	case ISO15693_CMD_WRITE_AFI:
	case ISO15693_CMD_LOCK_AFI:
	case ISO15693_CMD_WRITE_DSFID:
	case ISO15693_CMD_LOCK_DSFID:
		return 1;
		break;
	default:
		return 0;
	}
}

static int trf7970a_per_cmd_config(struct trf7970a *trf, struct sk_buff *skb)
{
	u8 *req = skb->data;
	u8 special_fcn_reg1, iso_ctrl;
	int ret;

	trf->issue_eof = false;

	/* When issuing Type 2 read command, make sure the '4_bit_RX' bit in
	 * special functions register 1 is cleared; otherwise, its a write or
	 * sector select command and '4_bit_RX' must be set.
	 *
	 * When issuing an ISO 15693 command, inspect the flags byte to see
	 * what speed to use.  Also, remember if the OPTION flag is set on
	 * a Type 5 write or lock command so the driver will know that it
	 * has to send an EOF in order to get a response.
	 */
	if ((trf->technology == NFC_DIGITAL_RF_TECH_106A) &&
			(trf->framing == NFC_DIGITAL_FRAMING_NFCA_T2T)) {
		if (req[0] == NFC_T2T_CMD_READ)
			special_fcn_reg1 = 0;
		else
			special_fcn_reg1 = TRF7970A_SPECIAL_FCN_REG1_4_BIT_RX;

		if (special_fcn_reg1 != trf->special_fcn_reg1) {
			ret = trf7970a_write(trf, TRF7970A_SPECIAL_FCN_REG1,
					special_fcn_reg1);
			if (ret)
				return ret;

			trf->special_fcn_reg1 = special_fcn_reg1;
		}
	} else if (trf->technology == NFC_DIGITAL_RF_TECH_ISO15693) {
		iso_ctrl = trf->iso_ctrl & ~TRF7970A_ISO_CTRL_RFID_SPEED_MASK;

		switch (req[0] & ISO15693_REQ_FLAG_SPEED_MASK) {
		case 0x00:
			iso_ctrl |= TRF7970A_ISO_CTRL_15693_SGL_1OF4_662;
			break;
		case ISO15693_REQ_FLAG_SUB_CARRIER:
			iso_ctrl |= TRF7970A_ISO_CTRL_15693_DBL_1OF4_667a;
			break;
		case ISO15693_REQ_FLAG_DATA_RATE:
			iso_ctrl |= TRF7970A_ISO_CTRL_15693_SGL_1OF4_2648;
			break;
		case (ISO15693_REQ_FLAG_SUB_CARRIER |
				ISO15693_REQ_FLAG_DATA_RATE):
			iso_ctrl |= TRF7970A_ISO_CTRL_15693_DBL_1OF4_2669;
			break;
		}

		if (iso_ctrl != trf->iso_ctrl) {
			ret = trf7970a_write(trf, TRF7970A_ISO_CTRL, iso_ctrl);
			if (ret)
				return ret;

			trf->iso_ctrl = iso_ctrl;
		}

		if (trf->framing == NFC_DIGITAL_FRAMING_ISO15693_T5T) {
			if (trf7970a_is_iso15693_write_or_lock(req[1]) &&
					(req[0] & ISO15693_REQ_FLAG_OPTION))
				trf->issue_eof = true;
			else if ((trf->quirks &
					TRF7970A_QUIRK_T5T_RMB_EXTRA_BYTE) &&
				 (req[1] == ISO15693_CMD_READ_MULTIPLE_BLOCK))
				trf->adjust_resp_len = true;
		}
	}

	return 0;
}

static int trf7970a_send_cmd(struct nfc_digital_dev *ddev,
		struct sk_buff *skb, u16 timeout,
		nfc_digital_cmd_complete_t cb, void *arg)
{
	struct trf7970a *trf = nfc_digital_get_drvdata(ddev);
	u8 prefix[5];
	unsigned int len;
	int ret;
	u8 status;

	dev_dbg(trf->dev, "New request - state: %d, timeout: %d ms, len: %d\n",
			trf->state, timeout, skb->len);

	if (skb->len > TRF7970A_TX_MAX)
		return -EINVAL;

	mutex_lock(&trf->lock);

	if ((trf->state != TRF7970A_ST_IDLE) &&
			(trf->state != TRF7970A_ST_IDLE_RX_BLOCKED)) {
		dev_err(trf->dev, "%s - Bogus state: %d\n", __func__,
				trf->state);
		ret = -EIO;
		goto out_err;
	}

	if (trf->aborting) {
		dev_dbg(trf->dev, "Abort process complete\n");
		trf->aborting = false;
		ret = -ECANCELED;
		goto out_err;
	}

	if (timeout) {
		trf->rx_skb = nfc_alloc_recv_skb(TRF7970A_RX_SKB_ALLOC_SIZE,
				GFP_KERNEL);
		if (!trf->rx_skb) {
			dev_dbg(trf->dev, "Can't alloc rx_skb\n");
			ret = -ENOMEM;
			goto out_err;
		}
	}

	if (trf->state == TRF7970A_ST_IDLE_RX_BLOCKED) {
		ret = trf7970a_cmd(trf, TRF7970A_CMD_ENABLE_RX);
		if (ret)
			goto out_err;

		trf->state = TRF7970A_ST_IDLE;
	}

	if (trf->is_initiator) {
		ret = trf7970a_per_cmd_config(trf, skb);
		if (ret)
			goto out_err;
	}

	trf->ddev = ddev;
	trf->tx_skb = skb;
	trf->cb = cb;
	trf->cb_arg = arg;
	trf->timeout = timeout;
	trf->ignore_timeout = false;

	len = skb->len;

	/* TX data must be prefixed with a FIFO reset cmd, a cmd that depends
	 * on what the current framing is, the address of the TX length byte 1
	 * register (0x1d), and the 2 byte length of the data to be transmitted.
	 * That totals 5 bytes.
	 */
	prefix[0] = TRF7970A_CMD_BIT_CTRL |
			TRF7970A_CMD_BIT_OPCODE(TRF7970A_CMD_FIFO_RESET);
	prefix[1] = TRF7970A_CMD_BIT_CTRL |
			TRF7970A_CMD_BIT_OPCODE(trf->tx_cmd);
	prefix[2] = TRF7970A_CMD_BIT_CONTINUOUS | TRF7970A_TX_LENGTH_BYTE1;

	if (trf->framing == NFC_DIGITAL_FRAMING_NFCA_SHORT) {
		prefix[3] = 0x00;
		prefix[4] = 0x0f; /* 7 bits */
	} else {
		prefix[3] = (len & 0xf00) >> 4;
		prefix[3] |= ((len & 0xf0) >> 4);
		prefix[4] = ((len & 0x0f) << 4);
	}

	len = min_t(int, skb->len, TRF7970A_FIFO_SIZE);

	/* Clear possible spurious interrupt */
	ret = trf7970a_read_irqstatus(trf, &status);
	if (ret)
		goto out_err;

	ret = trf7970a_transmit(trf, skb, len, prefix, sizeof(prefix));
	if (ret) {
		kfree_skb(trf->rx_skb);
		trf->rx_skb = NULL;
	}

out_err:
	mutex_unlock(&trf->lock);
	return ret;
}

static int trf7970a_tg_config_rf_tech(struct trf7970a *trf, int tech)
{
	int ret = 0;

	dev_dbg(trf->dev, "rf technology: %d\n", tech);

	switch (tech) {
	case NFC_DIGITAL_RF_TECH_106A:
		trf->iso_ctrl_tech = TRF7970A_ISO_CTRL_NFC_NFC_CE_MODE |
			TRF7970A_ISO_CTRL_NFC_CE |
			TRF7970A_ISO_CTRL_NFC_CE_14443A;
		trf->modulator_sys_clk_ctrl = TRF7970A_MODULATOR_DEPTH_OOK;
		break;
	case NFC_DIGITAL_RF_TECH_212F:
		trf->iso_ctrl_tech = TRF7970A_ISO_CTRL_NFC_NFC_CE_MODE |
			TRF7970A_ISO_CTRL_NFC_NFCF_212;
		trf->modulator_sys_clk_ctrl = TRF7970A_MODULATOR_DEPTH_ASK10;
		break;
	case NFC_DIGITAL_RF_TECH_424F:
		trf->iso_ctrl_tech = TRF7970A_ISO_CTRL_NFC_NFC_CE_MODE |
			TRF7970A_ISO_CTRL_NFC_NFCF_424;
		trf->modulator_sys_clk_ctrl = TRF7970A_MODULATOR_DEPTH_ASK10;
		break;
	default:
		dev_dbg(trf->dev, "Unsupported rf technology: %d\n", tech);
		return -EINVAL;
	}

	trf->technology = tech;

	/* Normally we write the ISO_CTRL register in
	 * trf7970a_tg_config_framing() because the framing can change
	 * the value written.  However, when sending a PSL RES,
	 * digital_tg_send_psl_res_complete() doesn't call
	 * trf7970a_tg_config_framing() so we must write the register
	 * here.
	 */
	if ((trf->framing == NFC_DIGITAL_FRAMING_NFC_DEP_ACTIVATED) &&
			(trf->iso_ctrl_tech != trf->iso_ctrl)) {
		ret = trf7970a_write(trf, TRF7970A_ISO_CTRL,
				trf->iso_ctrl_tech);

		trf->iso_ctrl = trf->iso_ctrl_tech;
	}

	return ret;
}

/* Since this is a target routine, several of the framing calls are
 * made between receiving the request and sending the response so they
 * should take effect until after the response is sent.  This is accomplished
 * by skipping the ISO_CTRL register write here and doing it in the interrupt
 * handler.
 */
static int trf7970a_tg_config_framing(struct trf7970a *trf, int framing)
{
	u8 iso_ctrl = trf->iso_ctrl_tech;
	int ret;

	dev_dbg(trf->dev, "framing: %d\n", framing);

	switch (framing) {
	case NFC_DIGITAL_FRAMING_NFCA_NFC_DEP:
		trf->tx_cmd = TRF7970A_CMD_TRANSMIT_NO_CRC;
		iso_ctrl |= TRF7970A_ISO_CTRL_RX_CRC_N;
		break;
	case NFC_DIGITAL_FRAMING_NFCA_STANDARD:
	case NFC_DIGITAL_FRAMING_NFCA_STANDARD_WITH_CRC_A:
	case NFC_DIGITAL_FRAMING_NFCA_ANTICOL_COMPLETE:
		/* These ones are applied in the interrupt handler */
		iso_ctrl = trf->iso_ctrl; /* Don't write to ISO_CTRL yet */
		break;
	case NFC_DIGITAL_FRAMING_NFCF_NFC_DEP:
		trf->tx_cmd = TRF7970A_CMD_TRANSMIT;
		iso_ctrl &= ~TRF7970A_ISO_CTRL_RX_CRC_N;
		break;
	case NFC_DIGITAL_FRAMING_NFC_DEP_ACTIVATED:
		trf->tx_cmd = TRF7970A_CMD_TRANSMIT;
		iso_ctrl &= ~TRF7970A_ISO_CTRL_RX_CRC_N;
		break;
	default:
		dev_dbg(trf->dev, "Unsupported Framing: %d\n", framing);
		return -EINVAL;
	}

	trf->framing = framing;

	if (iso_ctrl != trf->iso_ctrl) {
		ret = trf7970a_write(trf, TRF7970A_ISO_CTRL, iso_ctrl);
		if (ret)
			return ret;

		trf->iso_ctrl = iso_ctrl;

		ret = trf7970a_write(trf, TRF7970A_MODULATOR_SYS_CLK_CTRL,
				trf->modulator_sys_clk_ctrl);
		if (ret)
			return ret;
	}

	if (!(trf->chip_status_ctrl & TRF7970A_CHIP_STATUS_RF_ON)) {
		ret = trf7970a_write(trf, TRF7970A_CHIP_STATUS_CTRL,
				trf->chip_status_ctrl |
					TRF7970A_CHIP_STATUS_RF_ON);
		if (ret)
			return ret;

		trf->chip_status_ctrl |= TRF7970A_CHIP_STATUS_RF_ON;
	}

	return 0;
}

static int trf7970a_tg_configure_hw(struct nfc_digital_dev *ddev, int type,
		int param)
{
	struct trf7970a *trf = nfc_digital_get_drvdata(ddev);
	int ret;

	dev_dbg(trf->dev, "Configure hw - type: %d, param: %d\n", type, param);

	mutex_lock(&trf->lock);

	trf->is_initiator = false;

	if ((trf->state == TRF7970A_ST_PWR_OFF) ||
			(trf->state == TRF7970A_ST_RF_OFF)) {
		ret = trf7970a_switch_rf_on(trf);
		if (ret)
			goto err_unlock;
	}

	switch (type) {
	case NFC_DIGITAL_CONFIG_RF_TECH:
		ret = trf7970a_tg_config_rf_tech(trf, param);
		break;
	case NFC_DIGITAL_CONFIG_FRAMING:
		ret = trf7970a_tg_config_framing(trf, param);
		break;
	default:
		dev_dbg(trf->dev, "Unknown type: %d\n", type);
		ret = -EINVAL;
	}

err_unlock:
	mutex_unlock(&trf->lock);
	return ret;
}

static int _trf7970a_tg_listen(struct nfc_digital_dev *ddev, u16 timeout,
		nfc_digital_cmd_complete_t cb, void *arg, bool mode_detect)
{
	struct trf7970a *trf = nfc_digital_get_drvdata(ddev);
	int ret;

	mutex_lock(&trf->lock);

	if ((trf->state != TRF7970A_ST_IDLE) &&
			(trf->state != TRF7970A_ST_IDLE_RX_BLOCKED)) {
		dev_err(trf->dev, "%s - Bogus state: %d\n", __func__,
				trf->state);
		ret = -EIO;
		goto out_err;
	}

	if (trf->aborting) {
		dev_dbg(trf->dev, "Abort process complete\n");
		trf->aborting = false;
		ret = -ECANCELED;
		goto out_err;
	}

	trf->rx_skb = nfc_alloc_recv_skb(TRF7970A_RX_SKB_ALLOC_SIZE,
			GFP_KERNEL);
	if (!trf->rx_skb) {
		dev_dbg(trf->dev, "Can't alloc rx_skb\n");
		ret = -ENOMEM;
		goto out_err;
	}

	ret = trf7970a_write(trf, TRF7970A_RX_SPECIAL_SETTINGS,
			TRF7970A_RX_SPECIAL_SETTINGS_HBT |
			TRF7970A_RX_SPECIAL_SETTINGS_M848 |
			TRF7970A_RX_SPECIAL_SETTINGS_C424 |
			TRF7970A_RX_SPECIAL_SETTINGS_C212);
	if (ret)
		goto out_err;

	ret = trf7970a_write(trf, TRF7970A_REG_IO_CTRL,
			TRF7970A_REG_IO_CTRL_VRS(0x1));
	if (ret)
		goto out_err;

	ret = trf7970a_write(trf, TRF7970A_NFC_LOW_FIELD_LEVEL,
			TRF7970A_NFC_LOW_FIELD_LEVEL_RFDET(0x3));
	if (ret)
		goto out_err;

	ret = trf7970a_write(trf, TRF7970A_NFC_TARGET_LEVEL,
			TRF7970A_NFC_TARGET_LEVEL_RFDET(0x7));
	if (ret)
		goto out_err;

	trf->ddev = ddev;
	trf->cb = cb;
	trf->cb_arg = arg;
	trf->timeout = timeout;
	trf->ignore_timeout = false;

	ret = trf7970a_cmd(trf, TRF7970A_CMD_ENABLE_RX);
	if (ret)
		goto out_err;

	trf->state = mode_detect ? TRF7970A_ST_LISTENING_MD :
				   TRF7970A_ST_LISTENING;

	schedule_delayed_work(&trf->timeout_work, msecs_to_jiffies(timeout));

out_err:
	mutex_unlock(&trf->lock);
	return ret;
}

static int trf7970a_tg_listen(struct nfc_digital_dev *ddev, u16 timeout,
		nfc_digital_cmd_complete_t cb, void *arg)
{
	struct trf7970a *trf = nfc_digital_get_drvdata(ddev);

	dev_dbg(trf->dev, "Listen - state: %d, timeout: %d ms\n",
			trf->state, timeout);

	return _trf7970a_tg_listen(ddev, timeout, cb, arg, false);
}

static int trf7970a_tg_listen_md(struct nfc_digital_dev *ddev,
		u16 timeout, nfc_digital_cmd_complete_t cb, void *arg)
{
	struct trf7970a *trf = nfc_digital_get_drvdata(ddev);
	int ret;

	dev_dbg(trf->dev, "Listen MD - state: %d, timeout: %d ms\n",
			trf->state, timeout);

	ret = trf7970a_tg_configure_hw(ddev, NFC_DIGITAL_CONFIG_RF_TECH,
			NFC_DIGITAL_RF_TECH_106A);
	if (ret)
		return ret;

	ret = trf7970a_tg_configure_hw(ddev, NFC_DIGITAL_CONFIG_FRAMING,
			NFC_DIGITAL_FRAMING_NFCA_NFC_DEP);
	if (ret)
		return ret;

	return _trf7970a_tg_listen(ddev, timeout, cb, arg, true);
}

static int trf7970a_tg_get_rf_tech(struct nfc_digital_dev *ddev, u8 *rf_tech)
{
	struct trf7970a *trf = nfc_digital_get_drvdata(ddev);

	dev_dbg(trf->dev, "Get RF Tech - state: %d, rf_tech: %d\n",
			trf->state, trf->md_rf_tech);

	*rf_tech = trf->md_rf_tech;

	return 0;
}

static void trf7970a_abort_cmd(struct nfc_digital_dev *ddev)
{
	struct trf7970a *trf = nfc_digital_get_drvdata(ddev);

	dev_dbg(trf->dev, "Abort process initiated\n");

	mutex_lock(&trf->lock);

	switch (trf->state) {
	case TRF7970A_ST_WAIT_FOR_TX_FIFO:
	case TRF7970A_ST_WAIT_FOR_RX_DATA:
	case TRF7970A_ST_WAIT_FOR_RX_DATA_CONT:
	case TRF7970A_ST_WAIT_TO_ISSUE_EOF:
		trf->aborting = true;
		break;
	case TRF7970A_ST_LISTENING:
		trf->ignore_timeout = !cancel_delayed_work(&trf->timeout_work);
		trf7970a_send_err_upstream(trf, -ECANCELED);
		dev_dbg(trf->dev, "Abort process complete\n");
		break;
	default:
		break;
	}

	mutex_unlock(&trf->lock);
}

static struct nfc_digital_ops trf7970a_nfc_ops = {
	.in_configure_hw	= trf7970a_in_configure_hw,
	.in_send_cmd		= trf7970a_send_cmd,
	.tg_configure_hw	= trf7970a_tg_configure_hw,
	.tg_send_cmd		= trf7970a_send_cmd,
	.tg_listen		= trf7970a_tg_listen,
	.tg_listen_md		= trf7970a_tg_listen_md,
	.tg_get_rf_tech		= trf7970a_tg_get_rf_tech,
	.switch_rf		= trf7970a_switch_rf,
	.abort_cmd		= trf7970a_abort_cmd,
};

static int trf7970a_power_up(struct trf7970a *trf)
{
	int ret;

	dev_dbg(trf->dev, "Powering up - state: %d\n", trf->state);

	if (trf->state != TRF7970A_ST_PWR_OFF)
		return 0;

	ret = regulator_enable(trf->regulator);
	if (ret) {
		dev_err(trf->dev, "%s - Can't enable VIN: %d\n", __func__, ret);
		return ret;
	}

	usleep_range(5000, 6000);

	if (!(trf->quirks & TRF7970A_QUIRK_EN2_MUST_STAY_LOW)) {
		gpio_set_value(trf->en2_gpio, 1);
		usleep_range(1000, 2000);
	}

	gpio_set_value(trf->en_gpio, 1);

	usleep_range(20000, 21000);

	trf->state = TRF7970A_ST_RF_OFF;

	return 0;
}

static int trf7970a_power_down(struct trf7970a *trf)
{
	int ret;

	dev_dbg(trf->dev, "Powering down - state: %d\n", trf->state);

	if (trf->state == TRF7970A_ST_PWR_OFF)
		return 0;

	if (trf->state != TRF7970A_ST_RF_OFF) {
		dev_dbg(trf->dev, "Can't power down - not RF_OFF state (%d)\n",
				trf->state);
		return -EBUSY;
	}

	gpio_set_value(trf->en_gpio, 0);
	gpio_set_value(trf->en2_gpio, 0);

	ret = regulator_disable(trf->regulator);
	if (ret)
		dev_err(trf->dev, "%s - Can't disable VIN: %d\n", __func__,
				ret);

	trf->state = TRF7970A_ST_PWR_OFF;

	return ret;
}

static int trf7970a_startup(struct trf7970a *trf)
{
	int ret;

	ret = trf7970a_power_up(trf);
	if (ret)
		return ret;

	pm_runtime_set_active(trf->dev);
	pm_runtime_enable(trf->dev);
	pm_runtime_mark_last_busy(trf->dev);

	return 0;
}

static void trf7970a_shutdown(struct trf7970a *trf)
{
	switch (trf->state) {
	case TRF7970A_ST_WAIT_FOR_TX_FIFO:
	case TRF7970A_ST_WAIT_FOR_RX_DATA:
	case TRF7970A_ST_WAIT_FOR_RX_DATA_CONT:
	case TRF7970A_ST_WAIT_TO_ISSUE_EOF:
	case TRF7970A_ST_LISTENING:
		trf7970a_send_err_upstream(trf, -ECANCELED);
		/* FALLTHROUGH */
	case TRF7970A_ST_IDLE:
	case TRF7970A_ST_IDLE_RX_BLOCKED:
		trf7970a_switch_rf_off(trf);
		break;
	default:
		break;
	}

	pm_runtime_disable(trf->dev);
	pm_runtime_set_suspended(trf->dev);

	trf7970a_power_down(trf);
}

static int trf7970a_get_autosuspend_delay(struct device_node *np)
{
	int autosuspend_delay, ret;

	ret = of_property_read_u32(np, "autosuspend-delay", &autosuspend_delay);
	if (ret)
		autosuspend_delay = TRF7970A_AUTOSUSPEND_DELAY;

	return autosuspend_delay;
}

static int trf7970a_get_vin_voltage_override(struct device_node *np,
		u32 *vin_uvolts)
{
	return of_property_read_u32(np, "vin-voltage-override", vin_uvolts);
}

static int trf7970a_probe(struct spi_device *spi)
{
	struct device_node *np = spi->dev.of_node;
	struct trf7970a *trf;
	int uvolts, autosuspend_delay, ret;

	if (!np) {
		dev_err(&spi->dev, "No Device Tree entry\n");
		return -EINVAL;
	}

	trf = devm_kzalloc(&spi->dev, sizeof(*trf), GFP_KERNEL);
	if (!trf)
		return -ENOMEM;

	trf->state = TRF7970A_ST_PWR_OFF;
	trf->dev = &spi->dev;
	trf->spi = spi;

	spi->mode = SPI_MODE_1;
	spi->bits_per_word = 8;

	ret = spi_setup(spi);
	if (ret < 0) {
		dev_err(trf->dev, "Can't set up SPI Communication\n");
		return ret;
	}

	if (of_property_read_bool(np, "t5t-rmb-extra-byte-quirk"))
		trf->quirks |= TRF7970A_QUIRK_T5T_RMB_EXTRA_BYTE;

	if (of_property_read_bool(np, "irq-status-read-quirk"))
		trf->quirks |= TRF7970A_QUIRK_IRQ_STATUS_READ;

	/* There are two enable pins - both must be present */
	trf->en_gpio = of_get_named_gpio(np, "ti,enable-gpios", 0);
	if (!gpio_is_valid(trf->en_gpio)) {
		dev_err(trf->dev, "No EN GPIO property\n");
		return trf->en_gpio;
	}

	ret = devm_gpio_request_one(trf->dev, trf->en_gpio,
			GPIOF_DIR_OUT | GPIOF_INIT_LOW, "trf7970a EN");
	if (ret) {
		dev_err(trf->dev, "Can't request EN GPIO: %d\n", ret);
		return ret;
	}

	trf->en2_gpio = of_get_named_gpio(np, "ti,enable-gpios", 1);
	if (!gpio_is_valid(trf->en2_gpio)) {
		dev_err(trf->dev, "No EN2 GPIO property\n");
		return trf->en2_gpio;
	}

	ret = devm_gpio_request_one(trf->dev, trf->en2_gpio,
			GPIOF_DIR_OUT | GPIOF_INIT_LOW, "trf7970a EN2");
	if (ret) {
		dev_err(trf->dev, "Can't request EN2 GPIO: %d\n", ret);
		return ret;
	}

	if (of_property_read_bool(np, "en2-rf-quirk"))
		trf->quirks |= TRF7970A_QUIRK_EN2_MUST_STAY_LOW;

	ret = devm_request_threaded_irq(trf->dev, spi->irq, NULL,
			trf7970a_irq, IRQF_TRIGGER_RISING | IRQF_ONESHOT,
			"trf7970a", trf);
	if (ret) {
		dev_err(trf->dev, "Can't request IRQ#%d: %d\n", spi->irq, ret);
		return ret;
	}

	mutex_init(&trf->lock);
	INIT_DELAYED_WORK(&trf->timeout_work, trf7970a_timeout_work_handler);

	trf->regulator = devm_regulator_get(&spi->dev, "vin");
	if (IS_ERR(trf->regulator)) {
		ret = PTR_ERR(trf->regulator);
		dev_err(trf->dev, "Can't get VIN regulator: %d\n", ret);
		goto err_destroy_lock;
	}

	ret = regulator_enable(trf->regulator);
	if (ret) {
		dev_err(trf->dev, "Can't enable VIN: %d\n", ret);
		goto err_destroy_lock;
	}

	ret = trf7970a_get_vin_voltage_override(np, &uvolts);
	if (ret)
		uvolts = regulator_get_voltage(trf->regulator);

	if (uvolts > 4000000)
		trf->chip_status_ctrl = TRF7970A_CHIP_STATUS_VRS5_3;

	trf->ddev = nfc_digital_allocate_device(&trf7970a_nfc_ops,
			TRF7970A_SUPPORTED_PROTOCOLS,
			NFC_DIGITAL_DRV_CAPS_IN_CRC |
				NFC_DIGITAL_DRV_CAPS_TG_CRC, 0, 0);
	if (!trf->ddev) {
		dev_err(trf->dev, "Can't allocate NFC digital device\n");
		ret = -ENOMEM;
		goto err_disable_regulator;
	}

	nfc_digital_set_parent_dev(trf->ddev, trf->dev);
	nfc_digital_set_drvdata(trf->ddev, trf);
	spi_set_drvdata(spi, trf);

	autosuspend_delay = trf7970a_get_autosuspend_delay(np);

	pm_runtime_set_autosuspend_delay(trf->dev, autosuspend_delay);
	pm_runtime_use_autosuspend(trf->dev);

	ret = trf7970a_startup(trf);
	if (ret)
		goto err_free_ddev;

	ret = nfc_digital_register_device(trf->ddev);
	if (ret) {
		dev_err(trf->dev, "Can't register NFC digital device: %d\n",
				ret);
		goto err_shutdown;
	}

	return 0;

err_shutdown:
	trf7970a_shutdown(trf);
err_free_ddev:
	nfc_digital_free_device(trf->ddev);
err_disable_regulator:
	regulator_disable(trf->regulator);
err_destroy_lock:
	mutex_destroy(&trf->lock);
	return ret;
}

static int trf7970a_remove(struct spi_device *spi)
{
	struct trf7970a *trf = spi_get_drvdata(spi);

	mutex_lock(&trf->lock);

	trf7970a_shutdown(trf);

	mutex_unlock(&trf->lock);

	nfc_digital_unregister_device(trf->ddev);
	nfc_digital_free_device(trf->ddev);

	regulator_disable(trf->regulator);

	mutex_destroy(&trf->lock);

	return 0;
}

#ifdef CONFIG_PM_SLEEP
static int trf7970a_suspend(struct device *dev)
{
	struct spi_device *spi = to_spi_device(dev);
	struct trf7970a *trf = spi_get_drvdata(spi);

	dev_dbg(dev, "Suspend\n");

	mutex_lock(&trf->lock);

	trf7970a_shutdown(trf);

	mutex_unlock(&trf->lock);

	return 0;
}

static int trf7970a_resume(struct device *dev)
{
	struct spi_device *spi = to_spi_device(dev);
	struct trf7970a *trf = spi_get_drvdata(spi);
	int ret;

	dev_dbg(dev, "Resume\n");

	mutex_lock(&trf->lock);

	ret = trf7970a_startup(trf);

	mutex_unlock(&trf->lock);

	return ret;
}
#endif

#ifdef CONFIG_PM
static int trf7970a_pm_runtime_suspend(struct device *dev)
{
	struct spi_device *spi = to_spi_device(dev);
	struct trf7970a *trf = spi_get_drvdata(spi);
	int ret;

	dev_dbg(dev, "Runtime suspend\n");

	mutex_lock(&trf->lock);

	ret = trf7970a_power_down(trf);

	mutex_unlock(&trf->lock);

	return ret;
}

static int trf7970a_pm_runtime_resume(struct device *dev)
{
	struct spi_device *spi = to_spi_device(dev);
	struct trf7970a *trf = spi_get_drvdata(spi);
	int ret;

	dev_dbg(dev, "Runtime resume\n");

	ret = trf7970a_power_up(trf);
	if (!ret)
		pm_runtime_mark_last_busy(dev);

	return ret;
}
#endif

static const struct dev_pm_ops trf7970a_pm_ops = {
	SET_SYSTEM_SLEEP_PM_OPS(trf7970a_suspend, trf7970a_resume)
	SET_RUNTIME_PM_OPS(trf7970a_pm_runtime_suspend,
			trf7970a_pm_runtime_resume, NULL)
};

static const struct of_device_id trf7970a_of_match[] = {
	{ .compatible = "ti,trf7970a", },
	{ /* sentinel */ },
};
MODULE_DEVICE_TABLE(of, trf7970a_of_match);

static const struct spi_device_id trf7970a_id_table[] = {
	{ "trf7970a", 0 },
	{ }
};
MODULE_DEVICE_TABLE(spi, trf7970a_id_table);

static struct spi_driver trf7970a_spi_driver = {
	.probe		= trf7970a_probe,
	.remove		= trf7970a_remove,
	.id_table	= trf7970a_id_table,
	.driver		= {
		.name	= "trf7970a",
		.of_match_table = of_match_ptr(trf7970a_of_match),
		.pm	= &trf7970a_pm_ops,
	},
};

module_spi_driver(trf7970a_spi_driver);

MODULE_AUTHOR("Mark A. Greer <mgreer@animalcreek.com>");
MODULE_LICENSE("GPL v2");
MODULE_DESCRIPTION("TI trf7970a RFID/NFC Transceiver Driver");