summaryrefslogtreecommitdiff
path: root/drivers/usb/serial/cypress_m8.c
blob: e0035c0231202da04e88830e9b2c3e11e8416aad (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
// SPDX-License-Identifier: GPL-2.0+
/*
 * USB Cypress M8 driver
 *
 * 	Copyright (C) 2004
 * 	    Lonnie Mendez (dignome@gmail.com)
 *	Copyright (C) 2003,2004
 *	    Neil Whelchel (koyama@firstlight.net)
 *
 * See Documentation/usb/usb-serial.txt for more information on using this
 * driver
 *
 * See http://geocities.com/i0xox0i for information on this driver and the
 * earthmate usb device.
 */

/* Thanks to Neil Whelchel for writing the first cypress m8 implementation
   for linux. */
/* Thanks to cypress for providing references for the hid reports. */
/* Thanks to Jiang Zhang for providing links and for general help. */
/* Code originates and was built up from ftdi_sio, belkin, pl2303 and others.*/


#include <linux/kernel.h>
#include <linux/errno.h>
#include <linux/slab.h>
#include <linux/tty.h>
#include <linux/tty_driver.h>
#include <linux/tty_flip.h>
#include <linux/module.h>
#include <linux/moduleparam.h>
#include <linux/spinlock.h>
#include <linux/usb.h>
#include <linux/usb/serial.h>
#include <linux/serial.h>
#include <linux/kfifo.h>
#include <linux/delay.h>
#include <linux/uaccess.h>
#include <asm/unaligned.h>

#include "cypress_m8.h"


static bool stats;
static int interval;
static bool unstable_bauds;

#define DRIVER_AUTHOR "Lonnie Mendez <dignome@gmail.com>, Neil Whelchel <koyama@firstlight.net>"
#define DRIVER_DESC "Cypress USB to Serial Driver"

/* write buffer size defines */
#define CYPRESS_BUF_SIZE	1024

static const struct usb_device_id id_table_earthmate[] = {
	{ USB_DEVICE(VENDOR_ID_DELORME, PRODUCT_ID_EARTHMATEUSB) },
	{ USB_DEVICE(VENDOR_ID_DELORME, PRODUCT_ID_EARTHMATEUSB_LT20) },
	{ }						/* Terminating entry */
};

static const struct usb_device_id id_table_cyphidcomrs232[] = {
	{ USB_DEVICE(VENDOR_ID_CYPRESS, PRODUCT_ID_CYPHIDCOM) },
	{ USB_DEVICE(VENDOR_ID_POWERCOM, PRODUCT_ID_UPS) },
	{ USB_DEVICE(VENDOR_ID_FRWD, PRODUCT_ID_CYPHIDCOM_FRWD) },
	{ }						/* Terminating entry */
};

static const struct usb_device_id id_table_nokiaca42v2[] = {
	{ USB_DEVICE(VENDOR_ID_DAZZLE, PRODUCT_ID_CA42) },
	{ }						/* Terminating entry */
};

static const struct usb_device_id id_table_combined[] = {
	{ USB_DEVICE(VENDOR_ID_DELORME, PRODUCT_ID_EARTHMATEUSB) },
	{ USB_DEVICE(VENDOR_ID_DELORME, PRODUCT_ID_EARTHMATEUSB_LT20) },
	{ USB_DEVICE(VENDOR_ID_CYPRESS, PRODUCT_ID_CYPHIDCOM) },
	{ USB_DEVICE(VENDOR_ID_POWERCOM, PRODUCT_ID_UPS) },
	{ USB_DEVICE(VENDOR_ID_FRWD, PRODUCT_ID_CYPHIDCOM_FRWD) },
	{ USB_DEVICE(VENDOR_ID_DAZZLE, PRODUCT_ID_CA42) },
	{ }						/* Terminating entry */
};

MODULE_DEVICE_TABLE(usb, id_table_combined);

enum packet_format {
	packet_format_1,  /* b0:status, b1:payload count */
	packet_format_2   /* b0[7:3]:status, b0[2:0]:payload count */
};

struct cypress_private {
	spinlock_t lock;		   /* private lock */
	int chiptype;			   /* identifier of device, for quirks/etc */
	int bytes_in;			   /* used for statistics */
	int bytes_out;			   /* used for statistics */
	int cmd_count;			   /* used for statistics */
	int cmd_ctrl;			   /* always set this to 1 before issuing a command */
	struct kfifo write_fifo;	   /* write fifo */
	int write_urb_in_use;		   /* write urb in use indicator */
	int write_urb_interval;            /* interval to use for write urb */
	int read_urb_interval;             /* interval to use for read urb */
	int comm_is_ok;                    /* true if communication is (still) ok */
	int termios_initialized;
	__u8 line_control;	   	   /* holds dtr / rts value */
	__u8 current_status;	   	   /* received from last read - info on dsr,cts,cd,ri,etc */
	__u8 current_config;	   	   /* stores the current configuration byte */
	__u8 rx_flags;			   /* throttling - used from whiteheat/ftdi_sio */
	enum packet_format pkt_fmt;	   /* format to use for packet send / receive */
	int get_cfg_unsafe;		   /* If true, the CYPRESS_GET_CONFIG is unsafe */
	int baud_rate;			   /* stores current baud rate in
					      integer form */
	int isthrottled;		   /* if throttled, discard reads */
	char prev_status;		   /* used for TIOCMIWAIT */
	/* we pass a pointer to this as the argument sent to
	   cypress_set_termios old_termios */
	struct ktermios tmp_termios; 	   /* stores the old termios settings */
};

/* function prototypes for the Cypress USB to serial device */
static int  cypress_earthmate_port_probe(struct usb_serial_port *port);
static int  cypress_hidcom_port_probe(struct usb_serial_port *port);
static int  cypress_ca42v2_port_probe(struct usb_serial_port *port);
static int  cypress_port_remove(struct usb_serial_port *port);
static int  cypress_open(struct tty_struct *tty, struct usb_serial_port *port);
static void cypress_close(struct usb_serial_port *port);
static void cypress_dtr_rts(struct usb_serial_port *port, int on);
static int  cypress_write(struct tty_struct *tty, struct usb_serial_port *port,
			const unsigned char *buf, int count);
static void cypress_send(struct usb_serial_port *port);
static int  cypress_write_room(struct tty_struct *tty);
static void cypress_set_termios(struct tty_struct *tty,
			struct usb_serial_port *port, struct ktermios *old);
static int  cypress_tiocmget(struct tty_struct *tty);
static int  cypress_tiocmset(struct tty_struct *tty,
			unsigned int set, unsigned int clear);
static int  cypress_chars_in_buffer(struct tty_struct *tty);
static void cypress_throttle(struct tty_struct *tty);
static void cypress_unthrottle(struct tty_struct *tty);
static void cypress_set_dead(struct usb_serial_port *port);
static void cypress_read_int_callback(struct urb *urb);
static void cypress_write_int_callback(struct urb *urb);

static struct usb_serial_driver cypress_earthmate_device = {
	.driver = {
		.owner =		THIS_MODULE,
		.name =			"earthmate",
	},
	.description =			"DeLorme Earthmate USB",
	.id_table =			id_table_earthmate,
	.num_ports =			1,
	.port_probe =			cypress_earthmate_port_probe,
	.port_remove =			cypress_port_remove,
	.open =				cypress_open,
	.close =			cypress_close,
	.dtr_rts =			cypress_dtr_rts,
	.write =			cypress_write,
	.write_room =			cypress_write_room,
	.set_termios =			cypress_set_termios,
	.tiocmget =			cypress_tiocmget,
	.tiocmset =			cypress_tiocmset,
	.tiocmiwait =			usb_serial_generic_tiocmiwait,
	.chars_in_buffer =		cypress_chars_in_buffer,
	.throttle =		 	cypress_throttle,
	.unthrottle =			cypress_unthrottle,
	.read_int_callback =		cypress_read_int_callback,
	.write_int_callback =		cypress_write_int_callback,
};

static struct usb_serial_driver cypress_hidcom_device = {
	.driver = {
		.owner =		THIS_MODULE,
		.name =			"cyphidcom",
	},
	.description =			"HID->COM RS232 Adapter",
	.id_table =			id_table_cyphidcomrs232,
	.num_ports =			1,
	.port_probe =			cypress_hidcom_port_probe,
	.port_remove =			cypress_port_remove,
	.open =				cypress_open,
	.close =			cypress_close,
	.dtr_rts =			cypress_dtr_rts,
	.write =			cypress_write,
	.write_room =			cypress_write_room,
	.set_termios =			cypress_set_termios,
	.tiocmget =			cypress_tiocmget,
	.tiocmset =			cypress_tiocmset,
	.tiocmiwait =			usb_serial_generic_tiocmiwait,
	.chars_in_buffer =		cypress_chars_in_buffer,
	.throttle =			cypress_throttle,
	.unthrottle =			cypress_unthrottle,
	.read_int_callback =		cypress_read_int_callback,
	.write_int_callback =		cypress_write_int_callback,
};

static struct usb_serial_driver cypress_ca42v2_device = {
	.driver = {
		.owner =		THIS_MODULE,
		.name =			"nokiaca42v2",
	},
	.description =			"Nokia CA-42 V2 Adapter",
	.id_table =			id_table_nokiaca42v2,
	.num_ports =			1,
	.port_probe =			cypress_ca42v2_port_probe,
	.port_remove =			cypress_port_remove,
	.open =				cypress_open,
	.close =			cypress_close,
	.dtr_rts =			cypress_dtr_rts,
	.write =			cypress_write,
	.write_room =			cypress_write_room,
	.set_termios =			cypress_set_termios,
	.tiocmget =			cypress_tiocmget,
	.tiocmset =			cypress_tiocmset,
	.tiocmiwait =			usb_serial_generic_tiocmiwait,
	.chars_in_buffer =		cypress_chars_in_buffer,
	.throttle =			cypress_throttle,
	.unthrottle =			cypress_unthrottle,
	.read_int_callback =		cypress_read_int_callback,
	.write_int_callback =		cypress_write_int_callback,
};

static struct usb_serial_driver * const serial_drivers[] = {
	&cypress_earthmate_device, &cypress_hidcom_device,
	&cypress_ca42v2_device, NULL
};

/*****************************************************************************
 * Cypress serial helper functions
 *****************************************************************************/

/* FRWD Dongle hidcom needs to skip reset and speed checks */
static inline bool is_frwd(struct usb_device *dev)
{
	return ((le16_to_cpu(dev->descriptor.idVendor) == VENDOR_ID_FRWD) &&
		(le16_to_cpu(dev->descriptor.idProduct) == PRODUCT_ID_CYPHIDCOM_FRWD));
}

static int analyze_baud_rate(struct usb_serial_port *port, speed_t new_rate)
{
	struct cypress_private *priv;
	priv = usb_get_serial_port_data(port);

	if (unstable_bauds)
		return new_rate;

	/* FRWD Dongle uses 115200 bps */
	if (is_frwd(port->serial->dev))
		return new_rate;

	/*
	 * The general purpose firmware for the Cypress M8 allows for
	 * a maximum speed of 57600bps (I have no idea whether DeLorme
	 * chose to use the general purpose firmware or not), if you
	 * need to modify this speed setting for your own project
	 * please add your own chiptype and modify the code likewise.
	 * The Cypress HID->COM device will work successfully up to
	 * 115200bps (but the actual throughput is around 3kBps).
	 */
	if (port->serial->dev->speed == USB_SPEED_LOW) {
		/*
		 * Mike Isely <isely@pobox.com> 2-Feb-2008: The
		 * Cypress app note that describes this mechanism
		 * states the the low-speed part can't handle more
		 * than 800 bytes/sec, in which case 4800 baud is the
		 * safest speed for a part like that.
		 */
		if (new_rate > 4800) {
			dev_dbg(&port->dev,
				"%s - failed setting baud rate, device incapable speed %d\n",
				__func__, new_rate);
			return -1;
		}
	}
	switch (priv->chiptype) {
	case CT_EARTHMATE:
		if (new_rate <= 600) {
			/* 300 and 600 baud rates are supported under
			 * the generic firmware, but are not used with
			 * NMEA and SiRF protocols */
			dev_dbg(&port->dev,
				"%s - failed setting baud rate, unsupported speed of %d on Earthmate GPS\n",
				__func__, new_rate);
			return -1;
		}
		break;
	default:
		break;
	}
	return new_rate;
}


/* This function can either set or retrieve the current serial line settings */
static int cypress_serial_control(struct tty_struct *tty,
	struct usb_serial_port *port, speed_t baud_rate, int data_bits,
	int stop_bits, int parity_enable, int parity_type, int reset,
	int cypress_request_type)
{
	int new_baudrate = 0, retval = 0, tries = 0;
	struct cypress_private *priv;
	struct device *dev = &port->dev;
	u8 *feature_buffer;
	const unsigned int feature_len = 5;
	unsigned long flags;

	priv = usb_get_serial_port_data(port);

	if (!priv->comm_is_ok)
		return -ENODEV;

	feature_buffer = kcalloc(feature_len, sizeof(u8), GFP_KERNEL);
	if (!feature_buffer)
		return -ENOMEM;

	switch (cypress_request_type) {
	case CYPRESS_SET_CONFIG:
		/* 0 means 'Hang up' so doesn't change the true bit rate */
		new_baudrate = priv->baud_rate;
		if (baud_rate && baud_rate != priv->baud_rate) {
			dev_dbg(dev, "%s - baud rate is changing\n", __func__);
			retval = analyze_baud_rate(port, baud_rate);
			if (retval >= 0) {
				new_baudrate = retval;
				dev_dbg(dev, "%s - New baud rate set to %d\n",
					__func__, new_baudrate);
			}
		}
		dev_dbg(dev, "%s - baud rate is being sent as %d\n", __func__,
			new_baudrate);

		/* fill the feature_buffer with new configuration */
		put_unaligned_le32(new_baudrate, feature_buffer);
		feature_buffer[4] |= data_bits;   /* assign data bits in 2 bit space ( max 3 ) */
		/* 1 bit gap */
		feature_buffer[4] |= (stop_bits << 3);   /* assign stop bits in 1 bit space */
		feature_buffer[4] |= (parity_enable << 4);   /* assign parity flag in 1 bit space */
		feature_buffer[4] |= (parity_type << 5);   /* assign parity type in 1 bit space */
		/* 1 bit gap */
		feature_buffer[4] |= (reset << 7);   /* assign reset at end of byte, 1 bit space */

		dev_dbg(dev, "%s - device is being sent this feature report:\n", __func__);
		dev_dbg(dev, "%s - %02X - %02X - %02X - %02X - %02X\n", __func__,
			feature_buffer[0], feature_buffer[1],
			feature_buffer[2], feature_buffer[3],
			feature_buffer[4]);

		do {
			retval = usb_control_msg(port->serial->dev,
					usb_sndctrlpipe(port->serial->dev, 0),
					HID_REQ_SET_REPORT,
					USB_DIR_OUT | USB_RECIP_INTERFACE | USB_TYPE_CLASS,
					0x0300, 0, feature_buffer,
					feature_len, 500);

			if (tries++ >= 3)
				break;

		} while (retval != feature_len &&
			 retval != -ENODEV);

		if (retval != feature_len) {
			dev_err(dev, "%s - failed sending serial line settings - %d\n",
				__func__, retval);
			cypress_set_dead(port);
		} else {
			spin_lock_irqsave(&priv->lock, flags);
			priv->baud_rate = new_baudrate;
			priv->current_config = feature_buffer[4];
			spin_unlock_irqrestore(&priv->lock, flags);
			/* If we asked for a speed change encode it */
			if (baud_rate)
				tty_encode_baud_rate(tty,
					new_baudrate, new_baudrate);
		}
	break;
	case CYPRESS_GET_CONFIG:
		if (priv->get_cfg_unsafe) {
			/* Not implemented for this device,
			   and if we try to do it we're likely
			   to crash the hardware. */
			retval = -ENOTTY;
			goto out;
		}
		dev_dbg(dev, "%s - retreiving serial line settings\n", __func__);
		do {
			retval = usb_control_msg(port->serial->dev,
					usb_rcvctrlpipe(port->serial->dev, 0),
					HID_REQ_GET_REPORT,
					USB_DIR_IN | USB_RECIP_INTERFACE | USB_TYPE_CLASS,
					0x0300, 0, feature_buffer,
					feature_len, 500);

			if (tries++ >= 3)
				break;
		} while (retval != feature_len
						&& retval != -ENODEV);

		if (retval != feature_len) {
			dev_err(dev, "%s - failed to retrieve serial line settings - %d\n",
				__func__, retval);
			cypress_set_dead(port);
			goto out;
		} else {
			spin_lock_irqsave(&priv->lock, flags);
			/* store the config in one byte, and later
			   use bit masks to check values */
			priv->current_config = feature_buffer[4];
			priv->baud_rate = get_unaligned_le32(feature_buffer);
			spin_unlock_irqrestore(&priv->lock, flags);
		}
	}
	spin_lock_irqsave(&priv->lock, flags);
	++priv->cmd_count;
	spin_unlock_irqrestore(&priv->lock, flags);
out:
	kfree(feature_buffer);
	return retval;
} /* cypress_serial_control */


static void cypress_set_dead(struct usb_serial_port *port)
{
	struct cypress_private *priv = usb_get_serial_port_data(port);
	unsigned long flags;

	spin_lock_irqsave(&priv->lock, flags);
	if (!priv->comm_is_ok) {
		spin_unlock_irqrestore(&priv->lock, flags);
		return;
	}
	priv->comm_is_ok = 0;
	spin_unlock_irqrestore(&priv->lock, flags);

	dev_err(&port->dev, "cypress_m8 suspending failing port %d - "
		"interval might be too short\n", port->port_number);
}


/*****************************************************************************
 * Cypress serial driver functions
 *****************************************************************************/


static int cypress_generic_port_probe(struct usb_serial_port *port)
{
	struct usb_serial *serial = port->serial;
	struct cypress_private *priv;

	if (!port->interrupt_out_urb || !port->interrupt_in_urb) {
		dev_err(&port->dev, "required endpoint is missing\n");
		return -ENODEV;
	}

	priv = kzalloc(sizeof(struct cypress_private), GFP_KERNEL);
	if (!priv)
		return -ENOMEM;

	priv->comm_is_ok = !0;
	spin_lock_init(&priv->lock);
	if (kfifo_alloc(&priv->write_fifo, CYPRESS_BUF_SIZE, GFP_KERNEL)) {
		kfree(priv);
		return -ENOMEM;
	}

	/* Skip reset for FRWD device. It is a workaound:
	   device hangs if it receives SET_CONFIGURE in Configured
	   state. */
	if (!is_frwd(serial->dev))
		usb_reset_configuration(serial->dev);

	priv->cmd_ctrl = 0;
	priv->line_control = 0;
	priv->termios_initialized = 0;
	priv->rx_flags = 0;
	/* Default packet format setting is determined by packet size.
	   Anything with a size larger then 9 must have a separate
	   count field since the 3 bit count field is otherwise too
	   small.  Otherwise we can use the slightly more compact
	   format.  This is in accordance with the cypress_m8 serial
	   converter app note. */
	if (port->interrupt_out_size > 9)
		priv->pkt_fmt = packet_format_1;
	else
		priv->pkt_fmt = packet_format_2;

	if (interval > 0) {
		priv->write_urb_interval = interval;
		priv->read_urb_interval = interval;
		dev_dbg(&port->dev, "%s - read & write intervals forced to %d\n",
			__func__, interval);
	} else {
		priv->write_urb_interval = port->interrupt_out_urb->interval;
		priv->read_urb_interval = port->interrupt_in_urb->interval;
		dev_dbg(&port->dev, "%s - intervals: read=%d write=%d\n",
			__func__, priv->read_urb_interval,
			priv->write_urb_interval);
	}
	usb_set_serial_port_data(port, priv);

	port->port.drain_delay = 256;

	return 0;
}


static int cypress_earthmate_port_probe(struct usb_serial_port *port)
{
	struct usb_serial *serial = port->serial;
	struct cypress_private *priv;
	int ret;

	ret = cypress_generic_port_probe(port);
	if (ret) {
		dev_dbg(&port->dev, "%s - Failed setting up port\n", __func__);
		return ret;
	}

	priv = usb_get_serial_port_data(port);
	priv->chiptype = CT_EARTHMATE;
	/* All Earthmate devices use the separated-count packet
	   format!  Idiotic. */
	priv->pkt_fmt = packet_format_1;
	if (serial->dev->descriptor.idProduct !=
				cpu_to_le16(PRODUCT_ID_EARTHMATEUSB)) {
		/* The old original USB Earthmate seemed able to
		   handle GET_CONFIG requests; everything they've
		   produced since that time crashes if this command is
		   attempted :-( */
		dev_dbg(&port->dev,
			"%s - Marking this device as unsafe for GET_CONFIG commands\n",
			__func__);
		priv->get_cfg_unsafe = !0;
	}

	return 0;
}

static int cypress_hidcom_port_probe(struct usb_serial_port *port)
{
	struct cypress_private *priv;
	int ret;

	ret = cypress_generic_port_probe(port);
	if (ret) {
		dev_dbg(&port->dev, "%s - Failed setting up port\n", __func__);
		return ret;
	}

	priv = usb_get_serial_port_data(port);
	priv->chiptype = CT_CYPHIDCOM;

	return 0;
}

static int cypress_ca42v2_port_probe(struct usb_serial_port *port)
{
	struct cypress_private *priv;
	int ret;

	ret = cypress_generic_port_probe(port);
	if (ret) {
		dev_dbg(&port->dev, "%s - Failed setting up port\n", __func__);
		return ret;
	}

	priv = usb_get_serial_port_data(port);
	priv->chiptype = CT_CA42V2;

	return 0;
}

static int cypress_port_remove(struct usb_serial_port *port)
{
	struct cypress_private *priv;

	priv = usb_get_serial_port_data(port);

	kfifo_free(&priv->write_fifo);
	kfree(priv);

	return 0;
}

static int cypress_open(struct tty_struct *tty, struct usb_serial_port *port)
{
	struct cypress_private *priv = usb_get_serial_port_data(port);
	struct usb_serial *serial = port->serial;
	unsigned long flags;
	int result = 0;

	if (!priv->comm_is_ok)
		return -EIO;

	/* clear halts before open */
	usb_clear_halt(serial->dev, 0x81);
	usb_clear_halt(serial->dev, 0x02);

	spin_lock_irqsave(&priv->lock, flags);
	/* reset read/write statistics */
	priv->bytes_in = 0;
	priv->bytes_out = 0;
	priv->cmd_count = 0;
	priv->rx_flags = 0;
	spin_unlock_irqrestore(&priv->lock, flags);

	/* Set termios */
	cypress_send(port);

	if (tty)
		cypress_set_termios(tty, port, &priv->tmp_termios);

	/* setup the port and start reading from the device */
	usb_fill_int_urb(port->interrupt_in_urb, serial->dev,
		usb_rcvintpipe(serial->dev, port->interrupt_in_endpointAddress),
		port->interrupt_in_urb->transfer_buffer,
		port->interrupt_in_urb->transfer_buffer_length,
		cypress_read_int_callback, port, priv->read_urb_interval);
	result = usb_submit_urb(port->interrupt_in_urb, GFP_KERNEL);

	if (result) {
		dev_err(&port->dev,
			"%s - failed submitting read urb, error %d\n",
							__func__, result);
		cypress_set_dead(port);
	}

	return result;
} /* cypress_open */

static void cypress_dtr_rts(struct usb_serial_port *port, int on)
{
	struct cypress_private *priv = usb_get_serial_port_data(port);
	/* drop dtr and rts */
	spin_lock_irq(&priv->lock);
	if (on == 0)
		priv->line_control = 0;
	else 
		priv->line_control = CONTROL_DTR | CONTROL_RTS;
	priv->cmd_ctrl = 1;
	spin_unlock_irq(&priv->lock);
	cypress_write(NULL, port, NULL, 0);
}

static void cypress_close(struct usb_serial_port *port)
{
	struct cypress_private *priv = usb_get_serial_port_data(port);
	unsigned long flags;

	spin_lock_irqsave(&priv->lock, flags);
	kfifo_reset_out(&priv->write_fifo);
	spin_unlock_irqrestore(&priv->lock, flags);

	dev_dbg(&port->dev, "%s - stopping urbs\n", __func__);
	usb_kill_urb(port->interrupt_in_urb);
	usb_kill_urb(port->interrupt_out_urb);

	if (stats)
		dev_info(&port->dev, "Statistics: %d Bytes In | %d Bytes Out | %d Commands Issued\n",
			priv->bytes_in, priv->bytes_out, priv->cmd_count);
} /* cypress_close */


static int cypress_write(struct tty_struct *tty, struct usb_serial_port *port,
					const unsigned char *buf, int count)
{
	struct cypress_private *priv = usb_get_serial_port_data(port);

	dev_dbg(&port->dev, "%s - %d bytes\n", __func__, count);

	/* line control commands, which need to be executed immediately,
	   are not put into the buffer for obvious reasons.
	 */
	if (priv->cmd_ctrl) {
		count = 0;
		goto finish;
	}

	if (!count)
		return count;

	count = kfifo_in_locked(&priv->write_fifo, buf, count, &priv->lock);

finish:
	cypress_send(port);

	return count;
} /* cypress_write */


static void cypress_send(struct usb_serial_port *port)
{
	int count = 0, result, offset, actual_size;
	struct cypress_private *priv = usb_get_serial_port_data(port);
	struct device *dev = &port->dev;
	unsigned long flags;

	if (!priv->comm_is_ok)
		return;

	dev_dbg(dev, "%s - interrupt out size is %d\n", __func__,
		port->interrupt_out_size);

	spin_lock_irqsave(&priv->lock, flags);
	if (priv->write_urb_in_use) {
		dev_dbg(dev, "%s - can't write, urb in use\n", __func__);
		spin_unlock_irqrestore(&priv->lock, flags);
		return;
	}
	spin_unlock_irqrestore(&priv->lock, flags);

	/* clear buffer */
	memset(port->interrupt_out_urb->transfer_buffer, 0,
						port->interrupt_out_size);

	spin_lock_irqsave(&priv->lock, flags);
	switch (priv->pkt_fmt) {
	default:
	case packet_format_1:
		/* this is for the CY7C64013... */
		offset = 2;
		port->interrupt_out_buffer[0] = priv->line_control;
		break;
	case packet_format_2:
		/* this is for the CY7C63743... */
		offset = 1;
		port->interrupt_out_buffer[0] = priv->line_control;
		break;
	}

	if (priv->line_control & CONTROL_RESET)
		priv->line_control &= ~CONTROL_RESET;

	if (priv->cmd_ctrl) {
		priv->cmd_count++;
		dev_dbg(dev, "%s - line control command being issued\n", __func__);
		spin_unlock_irqrestore(&priv->lock, flags);
		goto send;
	} else
		spin_unlock_irqrestore(&priv->lock, flags);

	count = kfifo_out_locked(&priv->write_fifo,
					&port->interrupt_out_buffer[offset],
					port->interrupt_out_size - offset,
					&priv->lock);
	if (count == 0)
		return;

	switch (priv->pkt_fmt) {
	default:
	case packet_format_1:
		port->interrupt_out_buffer[1] = count;
		break;
	case packet_format_2:
		port->interrupt_out_buffer[0] |= count;
	}

	dev_dbg(dev, "%s - count is %d\n", __func__, count);

send:
	spin_lock_irqsave(&priv->lock, flags);
	priv->write_urb_in_use = 1;
	spin_unlock_irqrestore(&priv->lock, flags);

	if (priv->cmd_ctrl)
		actual_size = 1;
	else
		actual_size = count +
			      (priv->pkt_fmt == packet_format_1 ? 2 : 1);

	usb_serial_debug_data(dev, __func__, port->interrupt_out_size,
			      port->interrupt_out_urb->transfer_buffer);

	usb_fill_int_urb(port->interrupt_out_urb, port->serial->dev,
		usb_sndintpipe(port->serial->dev, port->interrupt_out_endpointAddress),
		port->interrupt_out_buffer, port->interrupt_out_size,
		cypress_write_int_callback, port, priv->write_urb_interval);
	result = usb_submit_urb(port->interrupt_out_urb, GFP_ATOMIC);
	if (result) {
		dev_err_console(port,
				"%s - failed submitting write urb, error %d\n",
							__func__, result);
		priv->write_urb_in_use = 0;
		cypress_set_dead(port);
	}

	spin_lock_irqsave(&priv->lock, flags);
	if (priv->cmd_ctrl)
		priv->cmd_ctrl = 0;

	/* do not count the line control and size bytes */
	priv->bytes_out += count;
	spin_unlock_irqrestore(&priv->lock, flags);

	usb_serial_port_softint(port);
} /* cypress_send */


/* returns how much space is available in the soft buffer */
static int cypress_write_room(struct tty_struct *tty)
{
	struct usb_serial_port *port = tty->driver_data;
	struct cypress_private *priv = usb_get_serial_port_data(port);
	int room = 0;
	unsigned long flags;

	spin_lock_irqsave(&priv->lock, flags);
	room = kfifo_avail(&priv->write_fifo);
	spin_unlock_irqrestore(&priv->lock, flags);

	dev_dbg(&port->dev, "%s - returns %d\n", __func__, room);
	return room;
}


static int cypress_tiocmget(struct tty_struct *tty)
{
	struct usb_serial_port *port = tty->driver_data;
	struct cypress_private *priv = usb_get_serial_port_data(port);
	__u8 status, control;
	unsigned int result = 0;
	unsigned long flags;

	spin_lock_irqsave(&priv->lock, flags);
	control = priv->line_control;
	status = priv->current_status;
	spin_unlock_irqrestore(&priv->lock, flags);

	result = ((control & CONTROL_DTR)        ? TIOCM_DTR : 0)
		| ((control & CONTROL_RTS)       ? TIOCM_RTS : 0)
		| ((status & UART_CTS)        ? TIOCM_CTS : 0)
		| ((status & UART_DSR)        ? TIOCM_DSR : 0)
		| ((status & UART_RI)         ? TIOCM_RI  : 0)
		| ((status & UART_CD)         ? TIOCM_CD  : 0);

	dev_dbg(&port->dev, "%s - result = %x\n", __func__, result);

	return result;
}


static int cypress_tiocmset(struct tty_struct *tty,
			       unsigned int set, unsigned int clear)
{
	struct usb_serial_port *port = tty->driver_data;
	struct cypress_private *priv = usb_get_serial_port_data(port);
	unsigned long flags;

	spin_lock_irqsave(&priv->lock, flags);
	if (set & TIOCM_RTS)
		priv->line_control |= CONTROL_RTS;
	if (set & TIOCM_DTR)
		priv->line_control |= CONTROL_DTR;
	if (clear & TIOCM_RTS)
		priv->line_control &= ~CONTROL_RTS;
	if (clear & TIOCM_DTR)
		priv->line_control &= ~CONTROL_DTR;
	priv->cmd_ctrl = 1;
	spin_unlock_irqrestore(&priv->lock, flags);

	return cypress_write(tty, port, NULL, 0);
}

static void cypress_set_termios(struct tty_struct *tty,
	struct usb_serial_port *port, struct ktermios *old_termios)
{
	struct cypress_private *priv = usb_get_serial_port_data(port);
	struct device *dev = &port->dev;
	int data_bits, stop_bits, parity_type, parity_enable;
	unsigned cflag, iflag;
	unsigned long flags;
	__u8 oldlines;
	int linechange = 0;

	spin_lock_irqsave(&priv->lock, flags);
	/* We can't clean this one up as we don't know the device type
	   early enough */
	if (!priv->termios_initialized) {
		if (priv->chiptype == CT_EARTHMATE) {
			tty->termios = tty_std_termios;
			tty->termios.c_cflag = B4800 | CS8 | CREAD | HUPCL |
				CLOCAL;
			tty->termios.c_ispeed = 4800;
			tty->termios.c_ospeed = 4800;
		} else if (priv->chiptype == CT_CYPHIDCOM) {
			tty->termios = tty_std_termios;
			tty->termios.c_cflag = B9600 | CS8 | CREAD | HUPCL |
				CLOCAL;
			tty->termios.c_ispeed = 9600;
			tty->termios.c_ospeed = 9600;
		} else if (priv->chiptype == CT_CA42V2) {
			tty->termios = tty_std_termios;
			tty->termios.c_cflag = B9600 | CS8 | CREAD | HUPCL |
				CLOCAL;
			tty->termios.c_ispeed = 9600;
			tty->termios.c_ospeed = 9600;
		}
		priv->termios_initialized = 1;
	}
	spin_unlock_irqrestore(&priv->lock, flags);

	/* Unsupported features need clearing */
	tty->termios.c_cflag &= ~(CMSPAR|CRTSCTS);

	cflag = tty->termios.c_cflag;
	iflag = tty->termios.c_iflag;

	/* check if there are new settings */
	if (old_termios) {
		spin_lock_irqsave(&priv->lock, flags);
		priv->tmp_termios = tty->termios;
		spin_unlock_irqrestore(&priv->lock, flags);
	}

	/* set number of data bits, parity, stop bits */
	/* when parity is disabled the parity type bit is ignored */

	/* 1 means 2 stop bits, 0 means 1 stop bit */
	stop_bits = cflag & CSTOPB ? 1 : 0;

	if (cflag & PARENB) {
		parity_enable = 1;
		/* 1 means odd parity, 0 means even parity */
		parity_type = cflag & PARODD ? 1 : 0;
	} else
		parity_enable = parity_type = 0;

	switch (cflag & CSIZE) {
	case CS5:
		data_bits = 0;
		break;
	case CS6:
		data_bits = 1;
		break;
	case CS7:
		data_bits = 2;
		break;
	case CS8:
		data_bits = 3;
		break;
	default:
		dev_err(dev, "%s - CSIZE was set, but not CS5-CS8\n", __func__);
		data_bits = 3;
	}
	spin_lock_irqsave(&priv->lock, flags);
	oldlines = priv->line_control;
	if ((cflag & CBAUD) == B0) {
		/* drop dtr and rts */
		dev_dbg(dev, "%s - dropping the lines, baud rate 0bps\n", __func__);
		priv->line_control &= ~(CONTROL_DTR | CONTROL_RTS);
	} else
		priv->line_control = (CONTROL_DTR | CONTROL_RTS);
	spin_unlock_irqrestore(&priv->lock, flags);

	dev_dbg(dev, "%s - sending %d stop_bits, %d parity_enable, %d parity_type, %d data_bits (+5)\n",
		__func__, stop_bits, parity_enable, parity_type, data_bits);

	cypress_serial_control(tty, port, tty_get_baud_rate(tty),
			data_bits, stop_bits,
			parity_enable, parity_type,
			0, CYPRESS_SET_CONFIG);

	/* we perform a CYPRESS_GET_CONFIG so that the current settings are
	 * filled into the private structure this should confirm that all is
	 * working if it returns what we just set */
	cypress_serial_control(tty, port, 0, 0, 0, 0, 0, 0, CYPRESS_GET_CONFIG);

	/* Here we can define custom tty settings for devices; the main tty
	 * termios flag base comes from empeg.c */

	spin_lock_irqsave(&priv->lock, flags);
	if (priv->chiptype == CT_EARTHMATE && priv->baud_rate == 4800) {
		dev_dbg(dev, "Using custom termios settings for a baud rate of 4800bps.\n");
		/* define custom termios settings for NMEA protocol */

		tty->termios.c_iflag /* input modes - */
			&= ~(IGNBRK  /* disable ignore break */
			| BRKINT     /* disable break causes interrupt */
			| PARMRK     /* disable mark parity errors */
			| ISTRIP     /* disable clear high bit of input char */
			| INLCR      /* disable translate NL to CR */
			| IGNCR      /* disable ignore CR */
			| ICRNL      /* disable translate CR to NL */
			| IXON);     /* disable enable XON/XOFF flow control */

		tty->termios.c_oflag /* output modes */
			&= ~OPOST;    /* disable postprocess output char */

		tty->termios.c_lflag /* line discipline modes */
			&= ~(ECHO     /* disable echo input characters */
			| ECHONL      /* disable echo new line */
			| ICANON      /* disable erase, kill, werase, and rprnt
					 special characters */
			| ISIG        /* disable interrupt, quit, and suspend
					 special characters */
			| IEXTEN);    /* disable non-POSIX special characters */
	} /* CT_CYPHIDCOM: Application should handle this for device */

	linechange = (priv->line_control != oldlines);
	spin_unlock_irqrestore(&priv->lock, flags);

	/* if necessary, set lines */
	if (linechange) {
		priv->cmd_ctrl = 1;
		cypress_write(tty, port, NULL, 0);
	}
} /* cypress_set_termios */


/* returns amount of data still left in soft buffer */
static int cypress_chars_in_buffer(struct tty_struct *tty)
{
	struct usb_serial_port *port = tty->driver_data;
	struct cypress_private *priv = usb_get_serial_port_data(port);
	int chars = 0;
	unsigned long flags;

	spin_lock_irqsave(&priv->lock, flags);
	chars = kfifo_len(&priv->write_fifo);
	spin_unlock_irqrestore(&priv->lock, flags);

	dev_dbg(&port->dev, "%s - returns %d\n", __func__, chars);
	return chars;
}


static void cypress_throttle(struct tty_struct *tty)
{
	struct usb_serial_port *port = tty->driver_data;
	struct cypress_private *priv = usb_get_serial_port_data(port);

	spin_lock_irq(&priv->lock);
	priv->rx_flags = THROTTLED;
	spin_unlock_irq(&priv->lock);
}


static void cypress_unthrottle(struct tty_struct *tty)
{
	struct usb_serial_port *port = tty->driver_data;
	struct cypress_private *priv = usb_get_serial_port_data(port);
	int actually_throttled, result;

	spin_lock_irq(&priv->lock);
	actually_throttled = priv->rx_flags & ACTUALLY_THROTTLED;
	priv->rx_flags = 0;
	spin_unlock_irq(&priv->lock);

	if (!priv->comm_is_ok)
		return;

	if (actually_throttled) {
		result = usb_submit_urb(port->interrupt_in_urb, GFP_KERNEL);
		if (result) {
			dev_err(&port->dev, "%s - failed submitting read urb, "
					"error %d\n", __func__, result);
			cypress_set_dead(port);
		}
	}
}


static void cypress_read_int_callback(struct urb *urb)
{
	struct usb_serial_port *port = urb->context;
	struct cypress_private *priv = usb_get_serial_port_data(port);
	struct device *dev = &urb->dev->dev;
	struct tty_struct *tty;
	unsigned char *data = urb->transfer_buffer;
	unsigned long flags;
	char tty_flag = TTY_NORMAL;
	int bytes = 0;
	int result;
	int i = 0;
	int status = urb->status;

	switch (status) {
	case 0: /* success */
		break;
	case -ECONNRESET:
	case -ENOENT:
	case -ESHUTDOWN:
		/* precursor to disconnect so just go away */
		return;
	case -EPIPE:
		/* Can't call usb_clear_halt while in_interrupt */
		/* FALLS THROUGH */
	default:
		/* something ugly is going on... */
		dev_err(dev, "%s - unexpected nonzero read status received: %d\n",
			__func__, status);
		cypress_set_dead(port);
		return;
	}

	spin_lock_irqsave(&priv->lock, flags);
	if (priv->rx_flags & THROTTLED) {
		dev_dbg(dev, "%s - now throttling\n", __func__);
		priv->rx_flags |= ACTUALLY_THROTTLED;
		spin_unlock_irqrestore(&priv->lock, flags);
		return;
	}
	spin_unlock_irqrestore(&priv->lock, flags);

	tty = tty_port_tty_get(&port->port);
	if (!tty) {
		dev_dbg(dev, "%s - bad tty pointer - exiting\n", __func__);
		return;
	}

	spin_lock_irqsave(&priv->lock, flags);
	result = urb->actual_length;
	switch (priv->pkt_fmt) {
	default:
	case packet_format_1:
		/* This is for the CY7C64013... */
		priv->current_status = data[0] & 0xF8;
		bytes = data[1] + 2;
		i = 2;
		break;
	case packet_format_2:
		/* This is for the CY7C63743... */
		priv->current_status = data[0] & 0xF8;
		bytes = (data[0] & 0x07) + 1;
		i = 1;
		break;
	}
	spin_unlock_irqrestore(&priv->lock, flags);
	if (result < bytes) {
		dev_dbg(dev,
			"%s - wrong packet size - received %d bytes but packet said %d bytes\n",
			__func__, result, bytes);
		goto continue_read;
	}

	usb_serial_debug_data(&port->dev, __func__, urb->actual_length, data);

	spin_lock_irqsave(&priv->lock, flags);
	/* check to see if status has changed */
	if (priv->current_status != priv->prev_status) {
		u8 delta = priv->current_status ^ priv->prev_status;

		if (delta & UART_MSR_MASK) {
			if (delta & UART_CTS)
				port->icount.cts++;
			if (delta & UART_DSR)
				port->icount.dsr++;
			if (delta & UART_RI)
				port->icount.rng++;
			if (delta & UART_CD)
				port->icount.dcd++;

			wake_up_interruptible(&port->port.delta_msr_wait);
		}

		priv->prev_status = priv->current_status;
	}
	spin_unlock_irqrestore(&priv->lock, flags);

	/* hangup, as defined in acm.c... this might be a bad place for it
	 * though */
	if (tty && !C_CLOCAL(tty) && !(priv->current_status & UART_CD)) {
		dev_dbg(dev, "%s - calling hangup\n", __func__);
		tty_hangup(tty);
		goto continue_read;
	}

	/* There is one error bit... I'm assuming it is a parity error
	 * indicator as the generic firmware will set this bit to 1 if a
	 * parity error occurs.
	 * I can not find reference to any other error events. */
	spin_lock_irqsave(&priv->lock, flags);
	if (priv->current_status & CYP_ERROR) {
		spin_unlock_irqrestore(&priv->lock, flags);
		tty_flag = TTY_PARITY;
		dev_dbg(dev, "%s - Parity Error detected\n", __func__);
	} else
		spin_unlock_irqrestore(&priv->lock, flags);

	/* process read if there is data other than line status */
	if (bytes > i) {
		tty_insert_flip_string_fixed_flag(&port->port, data + i,
				tty_flag, bytes - i);
		tty_flip_buffer_push(&port->port);
	}

	spin_lock_irqsave(&priv->lock, flags);
	/* control and status byte(s) are also counted */
	priv->bytes_in += bytes;
	spin_unlock_irqrestore(&priv->lock, flags);

continue_read:
	tty_kref_put(tty);

	/* Continue trying to always read */

	if (priv->comm_is_ok) {
		usb_fill_int_urb(port->interrupt_in_urb, port->serial->dev,
				usb_rcvintpipe(port->serial->dev,
					port->interrupt_in_endpointAddress),
				port->interrupt_in_urb->transfer_buffer,
				port->interrupt_in_urb->transfer_buffer_length,
				cypress_read_int_callback, port,
				priv->read_urb_interval);
		result = usb_submit_urb(port->interrupt_in_urb, GFP_ATOMIC);
		if (result && result != -EPERM) {
			dev_err(dev, "%s - failed resubmitting read urb, error %d\n",
				__func__, result);
			cypress_set_dead(port);
		}
	}
} /* cypress_read_int_callback */


static void cypress_write_int_callback(struct urb *urb)
{
	struct usb_serial_port *port = urb->context;
	struct cypress_private *priv = usb_get_serial_port_data(port);
	struct device *dev = &urb->dev->dev;
	int status = urb->status;

	switch (status) {
	case 0:
		/* success */
		break;
	case -ECONNRESET:
	case -ENOENT:
	case -ESHUTDOWN:
		/* this urb is terminated, clean up */
		dev_dbg(dev, "%s - urb shutting down with status: %d\n",
			__func__, status);
		priv->write_urb_in_use = 0;
		return;
	case -EPIPE:
		/* Cannot call usb_clear_halt while in_interrupt */
		/* FALLTHROUGH */
	default:
		dev_err(dev, "%s - unexpected nonzero write status received: %d\n",
			__func__, status);
		cypress_set_dead(port);
		break;
	}
	priv->write_urb_in_use = 0;

	/* send any buffered data */
	cypress_send(port);
}

module_usb_serial_driver(serial_drivers, id_table_combined);

MODULE_AUTHOR(DRIVER_AUTHOR);
MODULE_DESCRIPTION(DRIVER_DESC);
MODULE_LICENSE("GPL");

module_param(stats, bool, S_IRUGO | S_IWUSR);
MODULE_PARM_DESC(stats, "Enable statistics or not");
module_param(interval, int, S_IRUGO | S_IWUSR);
MODULE_PARM_DESC(interval, "Overrides interrupt interval");
module_param(unstable_bauds, bool, S_IRUGO | S_IWUSR);
MODULE_PARM_DESC(unstable_bauds, "Allow unstable baud rates");