aboutsummaryrefslogtreecommitdiffstats
path: root/drivers/i2c/chips/isp1301_omap.c
blob: 7f29a8aff1656792a46a75444dba89df70f05a91 (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
/*
 * isp1301_omap - ISP 1301 USB transceiver, talking to OMAP OTG controller
 *
 * Copyright (C) 2004 Texas Instruments
 * Copyright (C) 2004 David Brownell
 *
 * This program is free software; you can redistribute it and/or modify
 * it under the terms of the GNU General Public License as published by
 * the Free Software Foundation; either version 2 of the License, or
 * (at your option) any later version.
 *
 * This program is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 * GNU General Public License for more details.
 *
 * You should have received a copy of the GNU General Public License
 * along with this program; if not, write to the Free Software
 * Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
 */
#undef	DEBUG
#undef	VERBOSE

#include <linux/config.h>
#include <linux/kernel.h>
#include <linux/module.h>
#include <linux/init.h>
#include <linux/slab.h>
#include <linux/interrupt.h>
#include <linux/device.h>
#include <linux/usb_ch9.h>
#include <linux/usb_gadget.h>
#include <linux/usb.h>
#include <linux/usb_otg.h>
#include <linux/i2c.h>
#include <linux/workqueue.h>

#include <asm/irq.h>
#include <asm/arch/usb.h>


#ifndef	DEBUG
#undef	VERBOSE
#endif


#define	DRIVER_VERSION	"24 August 2004"
#define	DRIVER_NAME	(isp1301_driver.name)

MODULE_DESCRIPTION("ISP1301 USB OTG Transceiver Driver");
MODULE_LICENSE("GPL");

struct isp1301 {
	struct otg_transceiver	otg;
	struct i2c_client	client;
	void			(*i2c_release)(struct device *dev);

	int			irq;

	u32			last_otg_ctrl;
	unsigned		working:1;

	struct timer_list	timer;

	/* use keventd context to change the state for us */
	struct work_struct	work;
	
	unsigned long		todo;
#		define WORK_UPDATE_ISP	0	/* update ISP from OTG */
#		define WORK_UPDATE_OTG	1	/* update OTG from ISP */
#		define WORK_HOST_RESUME	4	/* resume host */
#		define WORK_TIMER	6	/* timer fired */
#		define WORK_STOP	7	/* don't resubmit */
};


/* bits in OTG_CTRL_REG */

#define	OTG_XCEIV_OUTPUTS \
	(OTG_ASESSVLD|OTG_BSESSEND|OTG_BSESSVLD|OTG_VBUSVLD|OTG_ID)
#define	OTG_XCEIV_INPUTS \
	(OTG_PULLDOWN|OTG_PULLUP|OTG_DRV_VBUS|OTG_PD_VBUS|OTG_PU_VBUS|OTG_PU_ID)
#define	OTG_CTRL_BITS \
	(OTG_A_BUSREQ|OTG_A_SETB_HNPEN|OTG_B_BUSREQ|OTG_B_HNPEN|OTG_BUSDROP)
	/* and OTG_PULLUP is sometimes written */

#define	OTG_CTRL_MASK	(OTG_DRIVER_SEL| \
	OTG_XCEIV_OUTPUTS|OTG_XCEIV_INPUTS| \
	OTG_CTRL_BITS)


/*-------------------------------------------------------------------------*/

#ifdef	CONFIG_MACH_OMAP_H2

/* board-specific PM hooks */

#include <asm/arch/gpio.h>
#include <asm/arch/mux.h>
#include <asm/mach-types.h>


#if	defined(CONFIG_TPS65010) || defined(CONFIG_TPS65010_MODULE)

#include <asm/arch/tps65010.h>

#else

static inline int tps65010_set_vbus_draw(unsigned mA)
{
	pr_debug("tps65010: draw %d mA (STUB)\n", mA);
	return 0;
}

#endif

static void enable_vbus_draw(struct isp1301 *isp, unsigned mA)
{
	int status = tps65010_set_vbus_draw(mA);
	if (status < 0)
		pr_debug("  VBUS %d mA error %d\n", mA, status);
}

static void enable_vbus_source(struct isp1301 *isp)
{
	/* this board won't supply more than 8mA vbus power.
	 * some boards can switch a 100ma "unit load" (or more).
	 */
}


/* products will deliver OTG messages with LEDs, GUI, etc */
static inline void notresponding(struct isp1301 *isp)
{
	printk(KERN_NOTICE "OTG device not responding.\n");
}


#endif

/*-------------------------------------------------------------------------*/

/* only two addresses possible */
#define	ISP_BASE		0x2c
static unsigned short normal_i2c[] = {
	ISP_BASE, ISP_BASE + 1,
	I2C_CLIENT_END };
static unsigned short normal_i2c_range[] = { I2C_CLIENT_END };

I2C_CLIENT_INSMOD;

static struct i2c_driver isp1301_driver;

/* smbus apis are used for portability */

static inline u8
isp1301_get_u8(struct isp1301 *isp, u8 reg)
{
	return i2c_smbus_read_byte_data(&isp->client, reg + 0);
}

static inline int
isp1301_get_u16(struct isp1301 *isp, u8 reg)
{
	return i2c_smbus_read_word_data(&isp->client, reg);
}

static inline int
isp1301_set_bits(struct isp1301 *isp, u8 reg, u8 bits)
{
	return i2c_smbus_write_byte_data(&isp->client, reg + 0, bits);
}

static inline int
isp1301_clear_bits(struct isp1301 *isp, u8 reg, u8 bits)
{
	return i2c_smbus_write_byte_data(&isp->client, reg + 1, bits);
}

/*-------------------------------------------------------------------------*/

/* identification */
#define	ISP1301_VENDOR_ID		0x00	/* u16 read */
#define	ISP1301_PRODUCT_ID		0x02	/* u16 read */
#define	ISP1301_BCD_DEVICE		0x14	/* u16 read */

#define	I2C_VENDOR_ID_PHILIPS		0x04cc
#define	I2C_PRODUCT_ID_PHILIPS_1301	0x1301

/* operational registers */
#define	ISP1301_MODE_CONTROL_1		0x04	/* u8 read, set, +1 clear */
#	define	MC1_SPEED_REG		(1 << 0)
#	define	MC1_SUSPEND_REG		(1 << 1)
#	define	MC1_DAT_SE0		(1 << 2)
#	define	MC1_TRANSPARENT		(1 << 3)
#	define	MC1_BDIS_ACON_EN	(1 << 4)
#	define	MC1_OE_INT_EN		(1 << 5)
#	define	MC1_UART_EN		(1 << 6)
#	define	MC1_MASK		0x7f
#define	ISP1301_MODE_CONTROL_2		0x12	/* u8 read, set, +1 clear */
#	define	MC2_GLOBAL_PWR_DN	(1 << 0)
#	define	MC2_SPD_SUSP_CTRL	(1 << 1)
#	define	MC2_BI_DI		(1 << 2)
#	define	MC2_TRANSP_BDIR0	(1 << 3)
#	define	MC2_TRANSP_BDIR1	(1 << 4)
#	define	MC2_AUDIO_EN		(1 << 5)
#	define	MC2_PSW_EN		(1 << 6)
#	define	MC2_EN2V7		(1 << 7)
#define	ISP1301_OTG_CONTROL_1		0x06	/* u8 read, set, +1 clear */
#	define	OTG1_DP_PULLUP		(1 << 0)
#	define	OTG1_DM_PULLUP		(1 << 1)
#	define	OTG1_DP_PULLDOWN	(1 << 2)
#	define	OTG1_DM_PULLDOWN	(1 << 3)
#	define	OTG1_ID_PULLDOWN	(1 << 4)
#	define	OTG1_VBUS_DRV		(1 << 5)
#	define	OTG1_VBUS_DISCHRG	(1 << 6)
#	define	OTG1_VBUS_CHRG		(1 << 7)
#define	ISP1301_OTG_STATUS		0x10	/* u8 readonly */
#	define	OTG_B_SESS_END		(1 << 6)
#	define	OTG_B_SESS_VLD		(1 << 7)

#define	ISP1301_INTERRUPT_SOURCE	0x08	/* u8 read */
#define	ISP1301_INTERRUPT_LATCH		0x0A	/* u8 read, set, +1 clear */

#define	ISP1301_INTERRUPT_FALLING	0x0C	/* u8 read, set, +1 clear */
#define	ISP1301_INTERRUPT_RISING	0x0E	/* u8 read, set, +1 clear */

/* same bitfields in all interrupt registers */
#	define	INTR_VBUS_VLD		(1 << 0)
#	define	INTR_SESS_VLD		(1 << 1)
#	define	INTR_DP_HI		(1 << 2)
#	define	INTR_ID_GND		(1 << 3)
#	define	INTR_DM_HI		(1 << 4)
#	define	INTR_ID_FLOAT		(1 << 5)
#	define	INTR_BDIS_ACON		(1 << 6)
#	define	INTR_CR_INT		(1 << 7)

/*-------------------------------------------------------------------------*/

static const char *state_string(enum usb_otg_state state)
{
	switch (state) {
	case OTG_STATE_A_IDLE:		return "a_idle";
	case OTG_STATE_A_WAIT_VRISE:	return "a_wait_vrise";
	case OTG_STATE_A_WAIT_BCON:	return "a_wait_bcon";
	case OTG_STATE_A_HOST:		return "a_host";
	case OTG_STATE_A_SUSPEND:	return "a_suspend";
	case OTG_STATE_A_PERIPHERAL:	return "a_peripheral";
	case OTG_STATE_A_WAIT_VFALL:	return "a_wait_vfall";
	case OTG_STATE_A_VBUS_ERR:	return "a_vbus_err";
	case OTG_STATE_B_IDLE:		return "b_idle";
	case OTG_STATE_B_SRP_INIT:	return "b_srp_init";
	case OTG_STATE_B_PERIPHERAL:	return "b_peripheral";
	case OTG_STATE_B_WAIT_ACON:	return "b_wait_acon";
	case OTG_STATE_B_HOST:		return "b_host";
	default:			return "UNDEFINED";
	}
}

static inline const char *state_name(struct isp1301 *isp)
{
	return state_string(isp->otg.state);
}

#ifdef	VERBOSE
#define	dev_vdbg			dev_dbg
#else
#define	dev_vdbg(dev, fmt, arg...)	do{}while(0)
#endif

/*-------------------------------------------------------------------------*/

/* NOTE:  some of this ISP1301 setup is specific to H2 boards;
 * not everything is guarded by board-specific checks, or even using
 * omap_usb_config data to deduce MC1_DAT_SE0 and MC2_BI_DI.
 *
 * ALSO:  this currently doesn't use ISP1301 low-power modes
 * while OTG is running.
 */

static void power_down(struct isp1301 *isp)
{
	isp->otg.state = OTG_STATE_UNDEFINED;

	// isp1301_set_bits(isp, ISP1301_MODE_CONTROL_2, MC2_GLOBAL_PWR_DN);
	isp1301_set_bits(isp, ISP1301_MODE_CONTROL_1, MC1_SUSPEND_REG);

	isp1301_clear_bits(isp, ISP1301_OTG_CONTROL_1, OTG1_ID_PULLDOWN);
	isp1301_clear_bits(isp, ISP1301_MODE_CONTROL_1, MC1_DAT_SE0);
}

static void power_up(struct isp1301 *isp)
{
	// isp1301_clear_bits(isp, ISP1301_MODE_CONTROL_2, MC2_GLOBAL_PWR_DN);
	isp1301_clear_bits(isp, ISP1301_MODE_CONTROL_1, MC1_SUSPEND_REG);
	
	/* do this only when cpu is driving transceiver,
	 * so host won't see a low speed device...
	 */
	isp1301_set_bits(isp, ISP1301_MODE_CONTROL_1, MC1_DAT_SE0);
}

#define	NO_HOST_SUSPEND

static int host_suspend(struct isp1301 *isp)
{
#ifdef	NO_HOST_SUSPEND
	return 0;
#else
	struct device	*dev;

	if (!isp->otg.host)
		return -ENODEV;

	/* Currently ASSUMES only the OTG port matters;
	 * other ports could be active...
	 */
	dev = isp->otg.host->controller;
	return dev->driver->suspend(dev, 3, 0);
#endif
}

static int host_resume(struct isp1301 *isp)
{
#ifdef	NO_HOST_SUSPEND
	return 0;
#else
	struct device	*dev;

	if (!isp->otg.host)
		return -ENODEV;

	dev = isp->otg.host->controller;
	return dev->driver->resume(dev, 0);
#endif
}

static int gadget_suspend(struct isp1301 *isp)
{
	isp->otg.gadget->b_hnp_enable = 0;
	isp->otg.gadget->a_hnp_support = 0;
	isp->otg.gadget->a_alt_hnp_support = 0;
	return usb_gadget_vbus_disconnect(isp->otg.gadget);
}

/*-------------------------------------------------------------------------*/

#define	TIMER_MINUTES	10
#define	TIMER_JIFFIES	(TIMER_MINUTES * 60 * HZ)

/* Almost all our I2C messaging comes from a work queue's task context.
 * NOTE: guaranteeing certain response times might mean we shouldn't
 * share keventd's work queue; a realtime task might be safest.
 */
void
isp1301_defer_work(struct isp1301 *isp, int work)
{
	int status;

	if (isp && !test_and_set_bit(work, &isp->todo)) {
		(void) get_device(&isp->client.dev);
		status = schedule_work(&isp->work);
		if (!status && !isp->working)
			dev_vdbg(&isp->client.dev,
				"work item %d may be lost\n", work);
	}
}

/* called from irq handlers */
static void a_idle(struct isp1301 *isp, const char *tag)
{
	if (isp->otg.state == OTG_STATE_A_IDLE)
		return;

	isp->otg.default_a = 1;
	if (isp->otg.host) {
		isp->otg.host->is_b_host = 0;
		host_suspend(isp);
	}
	if (isp->otg.gadget) {
		isp->otg.gadget->is_a_peripheral = 1;
		gadget_suspend(isp);
	}
	isp->otg.state = OTG_STATE_A_IDLE;
	isp->last_otg_ctrl = OTG_CTRL_REG = OTG_CTRL_REG & OTG_XCEIV_OUTPUTS;
	pr_debug("  --> %s/%s\n", state_name(isp), tag);
}

/* called from irq handlers */
static void b_idle(struct isp1301 *isp, const char *tag)
{
	if (isp->otg.state == OTG_STATE_B_IDLE)
		return;

	isp->otg.default_a = 0;
	if (isp->otg.host) {
		isp->otg.host->is_b_host = 1;
		host_suspend(isp);
	}
	if (isp->otg.gadget) {
		isp->otg.gadget->is_a_peripheral = 0;
		gadget_suspend(isp);
	}
	isp->otg.state = OTG_STATE_B_IDLE;
	isp->last_otg_ctrl = OTG_CTRL_REG = OTG_CTRL_REG & OTG_XCEIV_OUTPUTS;
	pr_debug("  --> %s/%s\n", state_name(isp), tag);
}

static void
dump_regs(struct isp1301 *isp, const char *label)
{
#ifdef	DEBUG
	u8	ctrl = isp1301_get_u8(isp, ISP1301_OTG_CONTROL_1);
	u8	status = isp1301_get_u8(isp, ISP1301_OTG_STATUS);
	u8	src = isp1301_get_u8(isp, ISP1301_INTERRUPT_SOURCE);

	pr_debug("otg: %06x, %s %s, otg/%02x stat/%02x.%02x\n",
		OTG_CTRL_REG, label, state_name(isp),
		ctrl, status, src);
	/* mode control and irq enables don't change much */
#endif
}

/*-------------------------------------------------------------------------*/

#ifdef	CONFIG_USB_OTG

/*
 * The OMAP OTG controller handles most of the OTG state transitions.
 *
 * We translate isp1301 outputs (mostly voltage comparator status) into
 * OTG inputs; OTG outputs (mostly pullup/pulldown controls) and HNP state
 * flags into isp1301 inputs ... and infer state transitions.
 */

#ifdef	VERBOSE

static void check_state(struct isp1301 *isp, const char *tag)
{
	enum usb_otg_state	state = OTG_STATE_UNDEFINED;
	u8			fsm = OTG_TEST_REG & 0x0ff;
	unsigned		extra = 0;

	switch (fsm) {

	/* default-b */
	case 0x0:
		state = OTG_STATE_B_IDLE;
		break;
	case 0x3:
	case 0x7:
		extra = 1;
	case 0x1:
		state = OTG_STATE_B_PERIPHERAL;
		break;
	case 0x11:
		state = OTG_STATE_B_SRP_INIT;
		break;

	/* extra dual-role default-b states */
	case 0x12:
	case 0x13:
	case 0x16:
		extra = 1;
	case 0x17:
		state = OTG_STATE_B_WAIT_ACON;
		break;
	case 0x34:
		state = OTG_STATE_B_HOST;
		break;

	/* default-a */
	case 0x36:
		state = OTG_STATE_A_IDLE;
		break;
	case 0x3c:
		state = OTG_STATE_A_WAIT_VFALL;
		break;
	case 0x7d:
		state = OTG_STATE_A_VBUS_ERR;
		break;
	case 0x9e:
	case 0x9f:
		extra = 1;
	case 0x89:
		state = OTG_STATE_A_PERIPHERAL;
		break;
	case 0xb7:
		state = OTG_STATE_A_WAIT_VRISE;
		break;
	case 0xb8:
		state = OTG_STATE_A_WAIT_BCON;
		break;
	case 0xb9:
		state = OTG_STATE_A_HOST;
		break;
	case 0xba:
		state = OTG_STATE_A_SUSPEND;
		break;
	default:
		break;
	}
	if (isp->otg.state == state && !extra)
		return;
	pr_debug("otg: %s FSM %s/%02x, %s, %06x\n", tag,
		state_string(state), fsm, state_name(isp), OTG_CTRL_REG);
}

#else

static inline void check_state(struct isp1301 *isp, const char *tag) { }

#endif

/* outputs from ISP1301_INTERRUPT_SOURCE */
static void update_otg1(struct isp1301 *isp, u8 int_src)
{
	u32	otg_ctrl;

	otg_ctrl = OTG_CTRL_REG
			& OTG_CTRL_MASK
			& ~OTG_XCEIV_INPUTS
			& ~(OTG_ID|OTG_ASESSVLD|OTG_VBUSVLD);
	if (int_src & INTR_SESS_VLD)
		otg_ctrl |= OTG_ASESSVLD;
	else if (isp->otg.state == OTG_STATE_A_WAIT_VFALL) {
		a_idle(isp, "vfall");
		otg_ctrl &= ~OTG_CTRL_BITS;
	}
	if (int_src & INTR_VBUS_VLD)
		otg_ctrl |= OTG_VBUSVLD;
	if (int_src & INTR_ID_GND) {		/* default-A */
		if (isp->otg.state == OTG_STATE_B_IDLE
				|| isp->otg.state == OTG_STATE_UNDEFINED) {
			a_idle(isp, "init");
			return;
		}
	} else {				/* default-B */
		otg_ctrl |= OTG_ID;
		if (isp->otg.state == OTG_STATE_A_IDLE
				|| isp->otg.state == OTG_STATE_UNDEFINED) {
			b_idle(isp, "init");
			return;
		}
	}
	OTG_CTRL_REG = otg_ctrl;
}

/* outputs from ISP1301_OTG_STATUS */
static void update_otg2(struct isp1301 *isp, u8 otg_status)
{
	u32	otg_ctrl;

	otg_ctrl = OTG_CTRL_REG
			& OTG_CTRL_MASK
			& ~OTG_XCEIV_INPUTS
			& ~(OTG_BSESSVLD|OTG_BSESSEND);
	if (otg_status & OTG_B_SESS_VLD)
		otg_ctrl |= OTG_BSESSVLD;
	else if (otg_status & OTG_B_SESS_END)
		otg_ctrl |= OTG_BSESSEND;
	OTG_CTRL_REG = otg_ctrl;
}

/* inputs going to ISP1301 */
static void otg_update_isp(struct isp1301 *isp)
{
	u32	otg_ctrl, otg_change;
	u8	set = OTG1_DM_PULLDOWN, clr = OTG1_DM_PULLUP;

	otg_ctrl = OTG_CTRL_REG;
	otg_change = otg_ctrl ^ isp->last_otg_ctrl;
	isp->last_otg_ctrl = otg_ctrl;
	otg_ctrl = otg_ctrl & OTG_XCEIV_INPUTS;

	switch (isp->otg.state) {
	case OTG_STATE_B_IDLE:
	case OTG_STATE_B_PERIPHERAL:
	case OTG_STATE_B_SRP_INIT:
		if (!(otg_ctrl & OTG_PULLUP)) {
			// if (otg_ctrl & OTG_B_HNPEN) {
			if (isp->otg.gadget->b_hnp_enable) {
				isp->otg.state = OTG_STATE_B_WAIT_ACON;
				pr_debug("  --> b_wait_acon\n");
			}
			goto pulldown;
		}
pullup:
		set |= OTG1_DP_PULLUP;
		clr |= OTG1_DP_PULLDOWN;
		break;
	case OTG_STATE_A_SUSPEND:
	case OTG_STATE_A_PERIPHERAL:
		if (otg_ctrl & OTG_PULLUP)
			goto pullup;
		/* FALLTHROUGH */
	// case OTG_STATE_B_WAIT_ACON:
	default:
pulldown:
		set |= OTG1_DP_PULLDOWN;
		clr |= OTG1_DP_PULLUP;
		break;
	}

#	define toggle(OTG,ISP) do { \
		if (otg_ctrl & OTG) set |= ISP; \
		else clr |= ISP; \
		} while (0)

	if (!(isp->otg.host))
		otg_ctrl &= ~OTG_DRV_VBUS;

	switch (isp->otg.state) {
	case OTG_STATE_A_SUSPEND:
		if (otg_ctrl & OTG_DRV_VBUS) {
			set |= OTG1_VBUS_DRV;
			break;
		}
		/* HNP failed for some reason (A_AIDL_BDIS timeout) */
		notresponding(isp);

		/* FALLTHROUGH */
	case OTG_STATE_A_VBUS_ERR:
		isp->otg.state = OTG_STATE_A_WAIT_VFALL;
		pr_debug("  --> a_wait_vfall\n");
		/* FALLTHROUGH */
	case OTG_STATE_A_WAIT_VFALL:
		/* FIXME usbcore thinks port power is still on ... */
		clr |= OTG1_VBUS_DRV;
		break;
	case OTG_STATE_A_IDLE:
		if (otg_ctrl & OTG_DRV_VBUS) {
			isp->otg.state = OTG_STATE_A_WAIT_VRISE;
			pr_debug("  --> a_wait_vrise\n");
		}
		/* FALLTHROUGH */
	default:
		toggle(OTG_DRV_VBUS, OTG1_VBUS_DRV);
	}

	toggle(OTG_PU_VBUS, OTG1_VBUS_CHRG);
	toggle(OTG_PD_VBUS, OTG1_VBUS_DISCHRG);

#	undef toggle

	isp1301_set_bits(isp, ISP1301_OTG_CONTROL_1, set);
	isp1301_clear_bits(isp, ISP1301_OTG_CONTROL_1, clr);

	/* HNP switch to host or peripheral; and SRP */
	if (otg_change & OTG_PULLUP) {
		switch (isp->otg.state) {
		case OTG_STATE_B_IDLE:
			if (clr & OTG1_DP_PULLUP)
				break;
			isp->otg.state = OTG_STATE_B_PERIPHERAL;
			pr_debug("  --> b_peripheral\n");
			break;
		case OTG_STATE_A_SUSPEND:
			if (clr & OTG1_DP_PULLUP)
				break;
			isp->otg.state = OTG_STATE_A_PERIPHERAL;
			pr_debug("  --> a_peripheral\n");
			break;
		default:
			break;
		}
		OTG_CTRL_REG |= OTG_PULLUP;
	}

	check_state(isp, __FUNCTION__);
	dump_regs(isp, "otg->isp1301");
}

static irqreturn_t omap_otg_irq(int irq, void *_isp, struct pt_regs *regs)
{
	u16		otg_irq = OTG_IRQ_SRC_REG;
	u32		otg_ctrl;
	int		ret = IRQ_NONE;
	struct isp1301	*isp = _isp;

	/* update ISP1301 transciever from OTG controller */
	if (otg_irq & OPRT_CHG) {
		OTG_IRQ_SRC_REG = OPRT_CHG;
		isp1301_defer_work(isp, WORK_UPDATE_ISP);
		ret = IRQ_HANDLED;

	/* SRP to become b_peripheral failed */
	} else if (otg_irq & B_SRP_TMROUT) {
		pr_debug("otg: B_SRP_TIMEOUT, %06x\n", OTG_CTRL_REG);
		notresponding(isp);

		/* gadget drivers that care should monitor all kinds of
		 * remote wakeup (SRP, normal) using their own timer
		 * to give "check cable and A-device" messages.
		 */
		if (isp->otg.state == OTG_STATE_B_SRP_INIT)
			b_idle(isp, "srp_timeout");

		OTG_IRQ_SRC_REG = B_SRP_TMROUT;
		ret = IRQ_HANDLED;

	/* HNP to become b_host failed */
	} else if (otg_irq & B_HNP_FAIL) {
		pr_debug("otg: %s B_HNP_FAIL, %06x\n",
				state_name(isp), OTG_CTRL_REG);
		notresponding(isp);

		otg_ctrl = OTG_CTRL_REG;
		otg_ctrl |= OTG_BUSDROP;
		otg_ctrl &= OTG_CTRL_MASK & ~OTG_XCEIV_INPUTS;
		OTG_CTRL_REG = otg_ctrl;

		/* subset of b_peripheral()... */
		isp->otg.state = OTG_STATE_B_PERIPHERAL;
		pr_debug("  --> b_peripheral\n");

		OTG_IRQ_SRC_REG = B_HNP_FAIL;
		ret = IRQ_HANDLED;

	/* detect SRP from B-device ... */
	} else if (otg_irq & A_SRP_DETECT) {
		pr_debug("otg: %s SRP_DETECT, %06x\n",
				state_name(isp), OTG_CTRL_REG);

		isp1301_defer_work(isp, WORK_UPDATE_OTG);
		switch (isp->otg.state) {
		case OTG_STATE_A_IDLE:
			if (!isp->otg.host)
				break;
			isp1301_defer_work(isp, WORK_HOST_RESUME);
			otg_ctrl = OTG_CTRL_REG;
			otg_ctrl |= OTG_A_BUSREQ;
			otg_ctrl &= ~(OTG_BUSDROP|OTG_B_BUSREQ)
					& ~OTG_XCEIV_INPUTS
					& OTG_CTRL_MASK;
			OTG_CTRL_REG = otg_ctrl;
			break;
		default:
			break;
		}

		OTG_IRQ_SRC_REG = A_SRP_DETECT;
		ret = IRQ_HANDLED;

	/* timer expired:  T(a_wait_bcon) and maybe T(a_wait_vrise)
	 * we don't track them separately
	 */
	} else if (otg_irq & A_REQ_TMROUT) {
		otg_ctrl = OTG_CTRL_REG;
		pr_info("otg: BCON_TMOUT from %s, %06x\n",
				state_name(isp), otg_ctrl);
		notresponding(isp);

		otg_ctrl |= OTG_BUSDROP;
		otg_ctrl &= ~OTG_A_BUSREQ & OTG_CTRL_MASK & ~OTG_XCEIV_INPUTS;
		OTG_CTRL_REG = otg_ctrl;
		isp->otg.state = OTG_STATE_A_WAIT_VFALL;

		OTG_IRQ_SRC_REG = A_REQ_TMROUT;
		ret = IRQ_HANDLED;

	/* A-supplied voltage fell too low; overcurrent */
	} else if (otg_irq & A_VBUS_ERR) {
		otg_ctrl = OTG_CTRL_REG;
		printk(KERN_ERR "otg: %s, VBUS_ERR %04x ctrl %06x\n",
			state_name(isp), otg_irq, otg_ctrl);

		otg_ctrl |= OTG_BUSDROP;
		otg_ctrl &= ~OTG_A_BUSREQ & OTG_CTRL_MASK & ~OTG_XCEIV_INPUTS;
		OTG_CTRL_REG = otg_ctrl;
		isp->otg.state = OTG_STATE_A_VBUS_ERR;

		OTG_IRQ_SRC_REG = A_VBUS_ERR;
		ret = IRQ_HANDLED;

	/* switch driver; the transciever code activates it,
	 * ungating the udc clock or resuming OHCI.
	 */
	} else if (otg_irq & DRIVER_SWITCH) {
		int	kick = 0;

		otg_ctrl = OTG_CTRL_REG;
		printk(KERN_NOTICE "otg: %s, SWITCH to %s, ctrl %06x\n",
				state_name(isp),
				(otg_ctrl & OTG_DRIVER_SEL)
					? "gadget" : "host",
				otg_ctrl);
		isp1301_defer_work(isp, WORK_UPDATE_ISP);

		/* role is peripheral */
		if (otg_ctrl & OTG_DRIVER_SEL) {
			switch (isp->otg.state) {
			case OTG_STATE_A_IDLE:
				b_idle(isp, __FUNCTION__);
				break;
			default:
				break;
			}
			isp1301_defer_work(isp, WORK_UPDATE_ISP);

		/* role is host */
		} else {
			if (!(otg_ctrl & OTG_ID)) {
		 		otg_ctrl &= OTG_CTRL_MASK & ~OTG_XCEIV_INPUTS;
				OTG_CTRL_REG = otg_ctrl | OTG_A_BUSREQ;
			}

			if (isp->otg.host) {
				switch (isp->otg.state) {
				case OTG_STATE_B_WAIT_ACON:
					isp->otg.state = OTG_STATE_B_HOST;
					pr_debug("  --> b_host\n");
					kick = 1;
					break;
				case OTG_STATE_A_WAIT_BCON:
					isp->otg.state = OTG_STATE_A_HOST;
					pr_debug("  --> a_host\n");
					break;
				case OTG_STATE_A_PERIPHERAL:
					isp->otg.state = OTG_STATE_A_WAIT_BCON;
					pr_debug("  --> a_wait_bcon\n");
					break;
				default:
					break;
				}
				isp1301_defer_work(isp, WORK_HOST_RESUME);
			}
		}

		OTG_IRQ_SRC_REG = DRIVER_SWITCH;
		ret = IRQ_HANDLED;

		if (kick)
			usb_bus_start_enum(isp->otg.host,
						isp->otg.host->otg_port);
	}

	check_state(isp, __FUNCTION__);
	return ret;
}

static struct platform_device *otg_dev;

static int otg_init(struct isp1301 *isp)
{
	if (!otg_dev)
		return -ENODEV;

	dump_regs(isp, __FUNCTION__);
	/* some of these values are board-specific... */
	OTG_SYSCON_2_REG |= OTG_EN
		/* for B-device: */
		| SRP_GPDATA		/* 9msec Bdev D+ pulse */
		| SRP_GPDVBUS		/* discharge after VBUS pulse */
		// | (3 << 24)		/* 2msec VBUS pulse */
		/* for A-device: */
		| (0 << 20)		/* 200ms nominal A_WAIT_VRISE timer */
		| SRP_DPW		/* detect 167+ns SRP pulses */
		| SRP_DATA | SRP_VBUS	/* accept both kinds of SRP pulse */
		;

	update_otg1(isp, isp1301_get_u8(isp, ISP1301_INTERRUPT_SOURCE));
	update_otg2(isp, isp1301_get_u8(isp, ISP1301_OTG_STATUS));

	check_state(isp, __FUNCTION__);
	pr_debug("otg: %s, %s %06x\n",
			state_name(isp), __FUNCTION__, OTG_CTRL_REG);

	OTG_IRQ_EN_REG = DRIVER_SWITCH | OPRT_CHG
			| B_SRP_TMROUT | B_HNP_FAIL
			| A_VBUS_ERR | A_SRP_DETECT | A_REQ_TMROUT;
	OTG_SYSCON_2_REG |= OTG_EN;

	return 0;
}

static int otg_probe(struct device *dev)
{
	// struct omap_usb_config *config = dev->platform_data;

	otg_dev = to_platform_device(dev);
	return 0;
}

static int otg_remove(struct device *dev)
{
	otg_dev = 0;
	return 0;
}

struct device_driver omap_otg_driver = {
	.name		= "omap_otg",
	.bus		= &platform_bus_type,
	.probe		= otg_probe,
	.remove		= otg_remove,	
};

static int otg_bind(struct isp1301 *isp)
{
	int	status;

	if (otg_dev)
		return -EBUSY;

	status = driver_register(&omap_otg_driver);
	if (status < 0)
		return status;

	if (otg_dev)
		status = request_irq(otg_dev->resource[1].start, omap_otg_irq,
				SA_INTERRUPT, DRIVER_NAME, isp);
	else
		status = -ENODEV;

	if (status < 0)
		driver_unregister(&omap_otg_driver);
	return status;
}

static void otg_unbind(struct isp1301 *isp)
{
	if (!otg_dev)
		return;
	free_irq(otg_dev->resource[1].start, isp);
}

#else

/* OTG controller isn't clocked */

#endif	/* CONFIG_USB_OTG */

/*-------------------------------------------------------------------------*/

static void b_peripheral(struct isp1301 *isp)
{
	OTG_CTRL_REG = OTG_CTRL_REG & OTG_XCEIV_OUTPUTS;
	usb_gadget_vbus_connect(isp->otg.gadget);

#ifdef	CONFIG_USB_OTG
	enable_vbus_draw(isp, 8);
	otg_update_isp(isp);
#else
	enable_vbus_draw(isp, 100);
	/* UDC driver just set OTG_BSESSVLD */
	isp1301_set_bits(isp, ISP1301_OTG_CONTROL_1, OTG1_DP_PULLUP);
	isp1301_clear_bits(isp, ISP1301_OTG_CONTROL_1, OTG1_DP_PULLDOWN);
	isp->otg.state = OTG_STATE_B_PERIPHERAL;
	pr_debug("  --> b_peripheral\n");
	dump_regs(isp, "2periph");
#endif
}

static void isp_update_otg(struct isp1301 *isp, u8 stat)
{
	u8			isp_stat, isp_bstat;
	enum usb_otg_state	state = isp->otg.state;

	if (stat & INTR_BDIS_ACON)
		pr_debug("OTG:  BDIS_ACON, %s\n", state_name(isp));

	/* start certain state transitions right away */
	isp_stat = isp1301_get_u8(isp, ISP1301_INTERRUPT_SOURCE);
	if (isp_stat & INTR_ID_GND) {
		if (isp->otg.default_a) {
			switch (state) {
			case OTG_STATE_B_IDLE:
				a_idle(isp, "idle");
				/* FALLTHROUGH */
			case OTG_STATE_A_IDLE:
				enable_vbus_source(isp);
				/* FALLTHROUGH */
			case OTG_STATE_A_WAIT_VRISE:
				/* we skip over OTG_STATE_A_WAIT_BCON, since
				 * the HC will transition to A_HOST (or
				 * A_SUSPEND!) without our noticing except
				 * when HNP is used.
				 */
				if (isp_stat & INTR_VBUS_VLD)
					isp->otg.state = OTG_STATE_A_HOST;
				break;
			case OTG_STATE_A_WAIT_VFALL:
				if (!(isp_stat & INTR_SESS_VLD))
					a_idle(isp, "vfell");
				break;
			default:
				if (!(isp_stat & INTR_VBUS_VLD))
					isp->otg.state = OTG_STATE_A_VBUS_ERR;
				break;
			}
			isp_bstat = isp1301_get_u8(isp, ISP1301_OTG_STATUS);
		} else {
			switch (state) {
			case OTG_STATE_B_PERIPHERAL:
			case OTG_STATE_B_HOST:
			case OTG_STATE_B_WAIT_ACON:
				usb_gadget_vbus_disconnect(isp->otg.gadget);
				break;
			default:
				break;
			}
			if (state != OTG_STATE_A_IDLE)
				a_idle(isp, "id");
			if (isp->otg.host && state == OTG_STATE_A_IDLE)
				isp1301_defer_work(isp, WORK_HOST_RESUME);
			isp_bstat = 0;
		}
	} else {
		/* if user unplugged mini-A end of cable,
		 * don't bypass A_WAIT_VFALL.
		 */
		if (isp->otg.default_a) {
			switch (state) {
			default:
				isp->otg.state = OTG_STATE_A_WAIT_VFALL;
				break;
			case OTG_STATE_A_WAIT_VFALL:
				state = OTG_STATE_A_IDLE;
				/* khubd may take a while to notice and
				 * handle this disconnect, so don't go
				 * to B_IDLE quite yet.
				 */
				break;
			case OTG_STATE_A_IDLE:
				host_suspend(isp);
				isp1301_clear_bits(isp, ISP1301_MODE_CONTROL_1,
						MC1_BDIS_ACON_EN);
				isp->otg.state = OTG_STATE_B_IDLE;
				OTG_CTRL_REG &= OTG_CTRL_REG & OTG_CTRL_MASK
						& ~OTG_CTRL_BITS;
				break;
			case OTG_STATE_B_IDLE:
				break;
			}
		}
		isp_bstat = isp1301_get_u8(isp, ISP1301_OTG_STATUS);

		switch (isp->otg.state) {
		case OTG_STATE_B_PERIPHERAL:
		case OTG_STATE_B_WAIT_ACON:
		case OTG_STATE_B_HOST:
			if (likely(isp_bstat & OTG_B_SESS_VLD))
				break;
			enable_vbus_draw(isp, 0);
#ifndef	CONFIG_USB_OTG
			/* UDC driver will clear OTG_BSESSVLD */
			isp1301_set_bits(isp, ISP1301_OTG_CONTROL_1,
						OTG1_DP_PULLDOWN);
			isp1301_clear_bits(isp, ISP1301_OTG_CONTROL_1,
						OTG1_DP_PULLUP);
			dump_regs(isp, __FUNCTION__);
#endif
			/* FALLTHROUGH */
		case OTG_STATE_B_SRP_INIT:
			b_idle(isp, __FUNCTION__);
			OTG_CTRL_REG &= OTG_CTRL_REG & OTG_XCEIV_OUTPUTS;
			/* FALLTHROUGH */
		case OTG_STATE_B_IDLE:
			if (isp->otg.gadget && (isp_bstat & OTG_B_SESS_VLD)) {
#ifdef	CONFIG_USB_OTG
				update_otg1(isp, isp_stat);
				update_otg2(isp, isp_bstat);
#endif
				b_peripheral(isp);
			} else if (!(isp_stat & (INTR_VBUS_VLD|INTR_SESS_VLD)))
				isp_bstat |= OTG_B_SESS_END;
			break;
		case OTG_STATE_A_WAIT_VFALL:
			break;
		default:
			pr_debug("otg: unsupported b-device %s\n",
				state_name(isp));
			break;
		}
	}

	if (state != isp->otg.state)
		pr_debug("  isp, %s -> %s\n",
				state_string(state), state_name(isp));

#ifdef	CONFIG_USB_OTG
	/* update the OTG controller state to match the isp1301; may
	 * trigger OPRT_CHG irqs for changes going to the isp1301.
	 */
	update_otg1(isp, isp_stat);
	update_otg2(isp, isp_bstat);
	check_state(isp, __FUNCTION__);
#endif

	dump_regs(isp, "isp1301->otg");
}

/*-------------------------------------------------------------------------*/

static u8 isp1301_clear_latch(struct isp1301 *isp)
{
	u8 latch = isp1301_get_u8(isp, ISP1301_INTERRUPT_LATCH);
	isp1301_clear_bits(isp, ISP1301_INTERRUPT_LATCH, latch);
	return latch;
}

static void
isp1301_work(void *data)
{
	struct isp1301	*isp = data;
	int		stop;

	/* implicit lock:  we're the only task using this device */
	isp->working = 1;
	do {
		stop = test_bit(WORK_STOP, &isp->todo);

#ifdef	CONFIG_USB_OTG
		/* transfer state from otg engine to isp1301 */
		if (test_and_clear_bit(WORK_UPDATE_ISP, &isp->todo)) {
			otg_update_isp(isp);
			put_device(&isp->client.dev);
		}
#endif
		/* transfer state from isp1301 to otg engine */
		if (test_and_clear_bit(WORK_UPDATE_OTG, &isp->todo)) {
			u8		stat = isp1301_clear_latch(isp);

			isp_update_otg(isp, stat);
			put_device(&isp->client.dev);
		}

		if (test_and_clear_bit(WORK_HOST_RESUME, &isp->todo)) {
			u32	otg_ctrl;

			/*
			 * skip A_WAIT_VRISE; hc transitions invisibly
			 * skip A_WAIT_BCON; same.
			 */
			switch (isp->otg.state) {
			case OTG_STATE_A_WAIT_BCON:
			case OTG_STATE_A_WAIT_VRISE:
				isp->otg.state = OTG_STATE_A_HOST;
				pr_debug("  --> a_host\n");
				otg_ctrl = OTG_CTRL_REG;
				otg_ctrl |= OTG_A_BUSREQ;
				otg_ctrl &= ~(OTG_BUSDROP|OTG_B_BUSREQ)
						& OTG_CTRL_MASK;
				OTG_CTRL_REG = otg_ctrl;
				break;
			case OTG_STATE_B_WAIT_ACON:
				isp->otg.state = OTG_STATE_B_HOST;
				pr_debug("  --> b_host (acon)\n");
				break;
			case OTG_STATE_B_HOST:
			case OTG_STATE_B_IDLE:
			case OTG_STATE_A_IDLE:
				break;
			default:
				pr_debug("  host resume in %s\n",
						state_name(isp));
			}
			host_resume(isp);
			// mdelay(10);
			put_device(&isp->client.dev);
		}

		if (test_and_clear_bit(WORK_TIMER, &isp->todo)) {
#ifdef	VERBOSE
			dump_regs(isp, "timer");
			if (!stop)
				mod_timer(&isp->timer, jiffies + TIMER_JIFFIES);
#endif
			put_device(&isp->client.dev);
		}

		if (isp->todo)
			dev_vdbg(&isp->client.dev,
				"work done, todo = 0x%lx\n",
				isp->todo);
		if (stop) {
			dev_dbg(&isp->client.dev, "stop\n");
			break;
		}
	} while (isp->todo);
	isp->working = 0;
}

static irqreturn_t isp1301_irq(int irq, void *isp, struct pt_regs *regs)
{
	isp1301_defer_work(isp, WORK_UPDATE_OTG);
	return IRQ_HANDLED;
}

static void isp1301_timer(unsigned long _isp)
{
	isp1301_defer_work((void *)_isp, WORK_TIMER);
}

/*-------------------------------------------------------------------------*/

static void isp1301_release(struct device *dev)
{
	struct isp1301	*isp;

	isp = container_of(dev, struct isp1301, client.dev);

	/* ugly -- i2c hijacks our memory hook to wait_for_completion() */
	if (isp->i2c_release)
		isp->i2c_release(dev);
	kfree (isp);
}

static struct isp1301 *the_transceiver;

static int isp1301_detach_client(struct i2c_client *i2c)
{
	struct isp1301	*isp;

	isp = container_of(i2c, struct isp1301, client);

	isp1301_clear_bits(isp, ISP1301_INTERRUPT_FALLING, ~0);
	isp1301_clear_bits(isp, ISP1301_INTERRUPT_RISING, ~0);
	free_irq(isp->irq, isp);
#ifdef	CONFIG_USB_OTG
	otg_unbind(isp);
#endif
	if (machine_is_omap_h2())
		omap_free_gpio(2);

	isp->timer.data = 0;
	set_bit(WORK_STOP, &isp->todo);
	del_timer_sync(&isp->timer);
	flush_scheduled_work();

	put_device(&i2c->dev);
	the_transceiver = 0;

	return i2c_detach_client(i2c);
}

/*-------------------------------------------------------------------------*/

/* NOTE:  three modes are possible here, only one of which
 * will be standards-conformant on any given system:
 *
 *  - OTG mode (dual-role), required if there's a Mini-AB connector
 *  - HOST mode, for when there's one or more A (host) connectors
 *  - DEVICE mode, for when there's a B/Mini-B (device) connector
 *
 * As a rule, you won't have an isp1301 chip unless it's there to
 * support the OTG mode.  Other modes help testing USB controllers 
 * in isolation from (full) OTG support, or maybe so later board
 * revisions can help to support those feature.
 */

#ifdef	CONFIG_USB_OTG

static int isp1301_otg_enable(struct isp1301 *isp)
{
	power_up(isp);
	otg_init(isp);

	/* NOTE:  since we don't change this, this provides
	 * a few more interrupts than are strictly needed.
	 */
	isp1301_set_bits(isp, ISP1301_INTERRUPT_RISING,
	 	INTR_VBUS_VLD | INTR_SESS_VLD | INTR_ID_GND);
	isp1301_set_bits(isp, ISP1301_INTERRUPT_FALLING,
	 	INTR_VBUS_VLD | INTR_SESS_VLD | INTR_ID_GND);

	dev_info(&isp->client.dev, "ready for dual-role USB ...\n");

	return 0;
}

#endif

/* add or disable the host device+driver */
static int
isp1301_set_host(struct otg_transceiver *otg, struct usb_bus *host)
{
	struct isp1301	*isp = container_of(otg, struct isp1301, otg);

	if (!otg || isp != the_transceiver)
		return -ENODEV;

	if (!host) {
		OTG_IRQ_EN_REG = 0;
		power_down(isp);
		isp->otg.host = 0;
		return 0;
	}

#ifdef	CONFIG_USB_OTG
	isp->otg.host = host;
	dev_dbg(&isp->client.dev, "registered host\n");
	host_suspend(isp);
	if (isp->otg.gadget)
		return isp1301_otg_enable(isp);
	return 0;

#elif	!defined(CONFIG_USB_GADGET_OMAP)
	// FIXME update its refcount
	isp->otg.host = host;

	power_up(isp);

	if (machine_is_omap_h2())
		isp1301_set_bits(isp, ISP1301_MODE_CONTROL_1, MC1_DAT_SE0);

	dev_info(&isp->client.dev, "A-Host sessions ok\n");
	isp1301_set_bits(isp, ISP1301_INTERRUPT_RISING,
	 	INTR_ID_GND);
	isp1301_set_bits(isp, ISP1301_INTERRUPT_FALLING,
	 	INTR_ID_GND);

	/* If this has a Mini-AB connector, this mode is highly
	 * nonstandard ... but can be handy for testing, especially with
	 * the Mini-A end of an OTG cable.  (Or something nonstandard
	 * like MiniB-to-StandardB, maybe built with a gender mender.)
	 */
	isp1301_set_bits(isp, ISP1301_OTG_CONTROL_1, OTG1_VBUS_DRV);

	dump_regs(isp, __FUNCTION__);

	return 0;

#else
	dev_dbg(&isp->client.dev, "host sessions not allowed\n");
	return -EINVAL;
#endif

}

static int
isp1301_set_peripheral(struct otg_transceiver *otg, struct usb_gadget *gadget)
{
	struct isp1301	*isp = container_of(otg, struct isp1301, otg);

	if (!otg || isp != the_transceiver)
		return -ENODEV;

	if (!gadget) {
		OTG_IRQ_EN_REG = 0;
		if (!isp->otg.default_a)
			enable_vbus_draw(isp, 0);
		usb_gadget_vbus_disconnect(isp->otg.gadget);
		isp->otg.gadget = 0;
		power_down(isp);
		return 0;
	}

#ifdef	CONFIG_USB_OTG
	isp->otg.gadget = gadget;
	dev_dbg(&isp->client.dev, "registered gadget\n");
	/* gadget driver may be suspended until vbus_connect () */
	if (isp->otg.host)
		return isp1301_otg_enable(isp);
	return 0;

#elif	!defined(CONFIG_USB_OHCI_HCD) && !defined(CONFIG_USB_OHCI_HCD_MODULE)
	isp->otg.gadget = gadget;
	// FIXME update its refcount

	OTG_CTRL_REG = (OTG_CTRL_REG & OTG_CTRL_MASK
				& ~(OTG_XCEIV_OUTPUTS|OTG_CTRL_BITS))
			| OTG_ID;
	power_up(isp);
	isp->otg.state = OTG_STATE_B_IDLE;

	if (machine_is_omap_h2())
		isp1301_set_bits(isp, ISP1301_MODE_CONTROL_1, MC1_DAT_SE0);

	isp1301_set_bits(isp, ISP1301_INTERRUPT_RISING,
	 	INTR_SESS_VLD);
	isp1301_set_bits(isp, ISP1301_INTERRUPT_FALLING,
	 	INTR_VBUS_VLD);
	dev_info(&isp->client.dev, "B-Peripheral sessions ok\n");
	dump_regs(isp, __FUNCTION__);

	/* If this has a Mini-AB connector, this mode is highly
	 * nonstandard ... but can be handy for testing, so long
	 * as you don't plug a Mini-A cable into the jack.
	 */
	if (isp1301_get_u8(isp, ISP1301_INTERRUPT_SOURCE) & INTR_VBUS_VLD)
		b_peripheral(isp);

	return 0;

#else
	dev_dbg(&isp->client.dev, "peripheral sessions not allowed\n");
	return -EINVAL;
#endif
}


/*-------------------------------------------------------------------------*/

static int
isp1301_set_power(struct otg_transceiver *dev, unsigned mA)
{
	if (!the_transceiver)
		return -ENODEV;
	if (dev->state == OTG_STATE_B_PERIPHERAL)
		enable_vbus_draw(the_transceiver, mA);
	return 0;
}

static int
isp1301_start_srp(struct otg_transceiver *dev)
{
	struct isp1301	*isp = container_of(dev, struct isp1301, otg);
	u32		otg_ctrl;

	if (!dev || isp != the_transceiver
			|| isp->otg.state != OTG_STATE_B_IDLE)
		return -ENODEV;

	otg_ctrl = OTG_CTRL_REG;
	if (!(otg_ctrl & OTG_BSESSEND))
		return -EINVAL;

	otg_ctrl |= OTG_B_BUSREQ;
	otg_ctrl &= ~OTG_A_BUSREQ & OTG_CTRL_MASK;
	OTG_CTRL_REG = otg_ctrl;
	isp->otg.state = OTG_STATE_B_SRP_INIT;

	pr_debug("otg: SRP, %s ... %06x\n", state_name(isp), OTG_CTRL_REG);
#ifdef	CONFIG_USB_OTG
	check_state(isp, __FUNCTION__);
#endif
	return 0;
}

static int
isp1301_start_hnp(struct otg_transceiver *dev)
{
#ifdef	CONFIG_USB_OTG
	struct isp1301	*isp = container_of(dev, struct isp1301, otg);

	if (!dev || isp != the_transceiver)
		return -ENODEV;
	if (isp->otg.default_a && (isp->otg.host == NULL
			|| !isp->otg.host->b_hnp_enable))
		return -ENOTCONN;
	if (!isp->otg.default_a && (isp->otg.gadget == NULL
			|| !isp->otg.gadget->b_hnp_enable))
		return -ENOTCONN;

	/* We want hardware to manage most HNP protocol timings.
	 * So do this part as early as possible...
	 */
	switch (isp->otg.state) {
	case OTG_STATE_B_HOST:
		isp->otg.state = OTG_STATE_B_PERIPHERAL;
		/* caller will suspend next */
		break;
	case OTG_STATE_A_HOST:
#if 0
		/* autoconnect mode avoids irq latency bugs */
		isp1301_set_bits(isp, ISP1301_MODE_CONTROL_1,
				MC1_BDIS_ACON_EN);
#endif
		/* caller must suspend then clear A_BUSREQ */
		usb_gadget_vbus_connect(isp->otg.gadget);
		OTG_CTRL_REG |= OTG_A_SETB_HNPEN;

		break;
	case OTG_STATE_A_PERIPHERAL:
		/* initiated by B-Host suspend */
		break;
	default:
		return -EILSEQ;
	}
	pr_debug("otg: HNP %s, %06x ...\n",
		state_name(isp), OTG_CTRL_REG);
	check_state(isp, __FUNCTION__);
	return 0;
#else
	/* srp-only */
	return -EINVAL;
#endif
}

/*-------------------------------------------------------------------------*/

/* no error returns, they'd just make bus scanning stop */
static int isp1301_probe(struct i2c_adapter *bus, int address, int kind)
{
	int			status;
	struct isp1301		*isp;
	struct i2c_client	*i2c;

	if (the_transceiver)
		return 0;

	isp = kcalloc(1, sizeof *isp, GFP_KERNEL);
	if (!isp)
		return 0;

	INIT_WORK(&isp->work, isp1301_work, isp);
	init_timer(&isp->timer);
	isp->timer.function = isp1301_timer;
	isp->timer.data = (unsigned long) isp;

	isp->irq = -1;
	isp->client.addr = address;
	i2c_set_clientdata(&isp->client, isp);
	isp->client.adapter = bus;
	isp->client.driver = &isp1301_driver;
	strlcpy(isp->client.name, DRIVER_NAME, I2C_NAME_SIZE);
	i2c = &isp->client;

	/* if this is a true probe, verify the chip ... */
	if (kind < 0) {
		status = isp1301_get_u16(isp, ISP1301_VENDOR_ID);
		if (status != I2C_VENDOR_ID_PHILIPS) {
			dev_dbg(&bus->dev, "addr %d not philips id: %d\n",
				address, status);
			goto fail1;
		}
		status = isp1301_get_u16(isp, ISP1301_PRODUCT_ID);
		if (status != I2C_PRODUCT_ID_PHILIPS_1301) {
			dev_dbg(&bus->dev, "%d not isp1301, %d\n",
				address, status);
			goto fail1;
		}
	}

	status = i2c_attach_client(i2c);
	if (status < 0) {
		dev_dbg(&bus->dev, "can't attach %s to device %d, err %d\n",
				DRIVER_NAME, address, status);
fail1:
		kfree(isp);
		return 0;
	}
	isp->i2c_release = i2c->dev.release;
	i2c->dev.release = isp1301_release;

	/* initial development used chiprev 2.00 */
	status = i2c_smbus_read_word_data(i2c, ISP1301_BCD_DEVICE);
	dev_info(&i2c->dev, "chiprev %x.%02x, driver " DRIVER_VERSION "\n",
		status >> 8, status & 0xff);

	/* make like power-on reset */
	isp1301_clear_bits(isp, ISP1301_MODE_CONTROL_1, MC1_MASK);

	isp1301_set_bits(isp, ISP1301_MODE_CONTROL_2, MC2_BI_DI);
	isp1301_clear_bits(isp, ISP1301_MODE_CONTROL_2, ~MC2_BI_DI);

	isp1301_set_bits(isp, ISP1301_OTG_CONTROL_1,
				OTG1_DM_PULLDOWN | OTG1_DP_PULLDOWN);
	isp1301_clear_bits(isp, ISP1301_OTG_CONTROL_1,
				~(OTG1_DM_PULLDOWN | OTG1_DP_PULLDOWN));

	isp1301_clear_bits(isp, ISP1301_INTERRUPT_LATCH, ~0);
	isp1301_clear_bits(isp, ISP1301_INTERRUPT_FALLING, ~0);
	isp1301_clear_bits(isp, ISP1301_INTERRUPT_RISING, ~0);

#ifdef	CONFIG_USB_OTG
	status = otg_bind(isp);
	if (status < 0) {
		dev_dbg(&i2c->dev, "can't bind OTG\n");
		goto fail2;
	}
#endif

	if (machine_is_omap_h2()) {
		/* full speed signaling by default */
		isp1301_set_bits(isp, ISP1301_MODE_CONTROL_1,
			MC1_SPEED_REG);
		isp1301_set_bits(isp, ISP1301_MODE_CONTROL_2,
			MC2_SPD_SUSP_CTRL);

		/* IRQ wired at M14 */
		omap_cfg_reg(M14_1510_GPIO2);
		isp->irq = OMAP_GPIO_IRQ(2);
		omap_request_gpio(2);
		omap_set_gpio_direction(2, 1);
		omap_set_gpio_edge_ctrl(2, OMAP_GPIO_FALLING_EDGE);
	}

	status = request_irq(isp->irq, isp1301_irq,
			SA_SAMPLE_RANDOM, DRIVER_NAME, isp);
	if (status < 0) {
		dev_dbg(&i2c->dev, "can't get IRQ %d, err %d\n",
				isp->irq, status);
#ifdef	CONFIG_USB_OTG
fail2:
#endif
		i2c_detach_client(i2c);
		goto fail1;
	}

	isp->otg.dev = &isp->client.dev;
	isp->otg.label = DRIVER_NAME;

	isp->otg.set_host = isp1301_set_host,
	isp->otg.set_peripheral = isp1301_set_peripheral,
	isp->otg.set_power = isp1301_set_power,
	isp->otg.start_srp = isp1301_start_srp,
	isp->otg.start_hnp = isp1301_start_hnp,

	enable_vbus_draw(isp, 0);
	power_down(isp);
	the_transceiver = isp;

#ifdef	CONFIG_USB_OTG
	update_otg1(isp, isp1301_get_u8(isp, ISP1301_INTERRUPT_SOURCE));
	update_otg2(isp, isp1301_get_u8(isp, ISP1301_OTG_STATUS));
#endif

	dump_regs(isp, __FUNCTION__);

#ifdef	VERBOSE
	mod_timer(&isp->timer, jiffies + TIMER_JIFFIES);
	dev_dbg(&i2c->dev, "scheduled timer, %d min\n", TIMER_MINUTES);
#endif

	status = otg_set_transceiver(&isp->otg);
	if (status < 0)
		dev_err(&i2c->dev, "can't register transceiver, %d\n",
			status);

	return 0;
}

static int isp1301_scan_bus(struct i2c_adapter *bus)
{
	if (!i2c_check_functionality(bus, I2C_FUNC_SMBUS_BYTE_DATA
			| I2C_FUNC_SMBUS_READ_WORD_DATA))
		return -EINVAL;
	return i2c_probe(bus, &addr_data, isp1301_probe);
}

static struct i2c_driver isp1301_driver = {
	.owner		= THIS_MODULE,
	.name		= "isp1301_omap",
	.id		= 1301,		/* FIXME "official", i2c-ids.h */
	.class		= I2C_CLASS_HWMON,
	.flags		= I2C_DF_NOTIFY,
	.attach_adapter	= isp1301_scan_bus,
	.detach_client	= isp1301_detach_client,
};

/*-------------------------------------------------------------------------*/

static int __init isp_init(void)
{
	return i2c_add_driver(&isp1301_driver);
}
module_init(isp_init);

static void __exit isp_exit(void)
{
	if (the_transceiver)
		otg_set_transceiver(0);
	i2c_del_driver(&isp1301_driver);
}
module_exit(isp_exit);