xref: /openbmc/linux/drivers/usb/serial/cypress_m8.c (revision 63dc02bd)
1 /*
2  * USB Cypress M8 driver
3  *
4  * 	Copyright (C) 2004
5  * 	    Lonnie Mendez (dignome@gmail.com)
6  *	Copyright (C) 2003,2004
7  *	    Neil Whelchel (koyama@firstlight.net)
8  *
9  * 	This program is free software; you can redistribute it and/or modify
10  * 	it under the terms of the GNU General Public License as published by
11  * 	the Free Software Foundation; either version 2 of the License, or
12  * 	(at your option) any later version.
13  *
14  * See Documentation/usb/usb-serial.txt for more information on using this
15  * driver
16  *
17  * See http://geocities.com/i0xox0i for information on this driver and the
18  * earthmate usb device.
19  */
20 
21 /* Thanks to Neil Whelchel for writing the first cypress m8 implementation
22    for linux. */
23 /* Thanks to cypress for providing references for the hid reports. */
24 /* Thanks to Jiang Zhang for providing links and for general help. */
25 /* Code originates and was built up from ftdi_sio, belkin, pl2303 and others.*/
26 
27 
28 #include <linux/kernel.h>
29 #include <linux/errno.h>
30 #include <linux/init.h>
31 #include <linux/slab.h>
32 #include <linux/tty.h>
33 #include <linux/tty_driver.h>
34 #include <linux/tty_flip.h>
35 #include <linux/module.h>
36 #include <linux/moduleparam.h>
37 #include <linux/spinlock.h>
38 #include <linux/usb.h>
39 #include <linux/usb/serial.h>
40 #include <linux/serial.h>
41 #include <linux/kfifo.h>
42 #include <linux/delay.h>
43 #include <linux/uaccess.h>
44 #include <asm/unaligned.h>
45 
46 #include "cypress_m8.h"
47 
48 
49 static bool debug;
50 static bool stats;
51 static int interval;
52 static bool unstable_bauds;
53 
54 /*
55  * Version Information
56  */
57 #define DRIVER_VERSION "v1.10"
58 #define DRIVER_AUTHOR "Lonnie Mendez <dignome@gmail.com>, Neil Whelchel <koyama@firstlight.net>"
59 #define DRIVER_DESC "Cypress USB to Serial Driver"
60 
61 /* write buffer size defines */
62 #define CYPRESS_BUF_SIZE	1024
63 
64 static const struct usb_device_id id_table_earthmate[] = {
65 	{ USB_DEVICE(VENDOR_ID_DELORME, PRODUCT_ID_EARTHMATEUSB) },
66 	{ USB_DEVICE(VENDOR_ID_DELORME, PRODUCT_ID_EARTHMATEUSB_LT20) },
67 	{ }						/* Terminating entry */
68 };
69 
70 static const struct usb_device_id id_table_cyphidcomrs232[] = {
71 	{ USB_DEVICE(VENDOR_ID_CYPRESS, PRODUCT_ID_CYPHIDCOM) },
72 	{ USB_DEVICE(VENDOR_ID_POWERCOM, PRODUCT_ID_UPS) },
73 	{ }						/* Terminating entry */
74 };
75 
76 static const struct usb_device_id id_table_nokiaca42v2[] = {
77 	{ USB_DEVICE(VENDOR_ID_DAZZLE, PRODUCT_ID_CA42) },
78 	{ }						/* Terminating entry */
79 };
80 
81 static const struct usb_device_id id_table_combined[] = {
82 	{ USB_DEVICE(VENDOR_ID_DELORME, PRODUCT_ID_EARTHMATEUSB) },
83 	{ USB_DEVICE(VENDOR_ID_DELORME, PRODUCT_ID_EARTHMATEUSB_LT20) },
84 	{ USB_DEVICE(VENDOR_ID_CYPRESS, PRODUCT_ID_CYPHIDCOM) },
85 	{ USB_DEVICE(VENDOR_ID_POWERCOM, PRODUCT_ID_UPS) },
86 	{ USB_DEVICE(VENDOR_ID_DAZZLE, PRODUCT_ID_CA42) },
87 	{ }						/* Terminating entry */
88 };
89 
90 MODULE_DEVICE_TABLE(usb, id_table_combined);
91 
92 static struct usb_driver cypress_driver = {
93 	.name =		"cypress",
94 	.probe =	usb_serial_probe,
95 	.disconnect =	usb_serial_disconnect,
96 	.id_table =	id_table_combined,
97 };
98 
99 enum packet_format {
100 	packet_format_1,  /* b0:status, b1:payload count */
101 	packet_format_2   /* b0[7:3]:status, b0[2:0]:payload count */
102 };
103 
104 struct cypress_private {
105 	spinlock_t lock;		   /* private lock */
106 	int chiptype;			   /* identifier of device, for quirks/etc */
107 	int bytes_in;			   /* used for statistics */
108 	int bytes_out;			   /* used for statistics */
109 	int cmd_count;			   /* used for statistics */
110 	int cmd_ctrl;			   /* always set this to 1 before issuing a command */
111 	struct kfifo write_fifo;	   /* write fifo */
112 	int write_urb_in_use;		   /* write urb in use indicator */
113 	int write_urb_interval;            /* interval to use for write urb */
114 	int read_urb_interval;             /* interval to use for read urb */
115 	int comm_is_ok;                    /* true if communication is (still) ok */
116 	int termios_initialized;
117 	__u8 line_control;	   	   /* holds dtr / rts value */
118 	__u8 current_status;	   	   /* received from last read - info on dsr,cts,cd,ri,etc */
119 	__u8 current_config;	   	   /* stores the current configuration byte */
120 	__u8 rx_flags;			   /* throttling - used from whiteheat/ftdi_sio */
121 	enum packet_format pkt_fmt;	   /* format to use for packet send / receive */
122 	int get_cfg_unsafe;		   /* If true, the CYPRESS_GET_CONFIG is unsafe */
123 	int baud_rate;			   /* stores current baud rate in
124 					      integer form */
125 	int isthrottled;		   /* if throttled, discard reads */
126 	wait_queue_head_t delta_msr_wait;  /* used for TIOCMIWAIT */
127 	char prev_status, diff_status;	   /* used for TIOCMIWAIT */
128 	/* we pass a pointer to this as the argument sent to
129 	   cypress_set_termios old_termios */
130 	struct ktermios tmp_termios; 	   /* stores the old termios settings */
131 };
132 
133 /* function prototypes for the Cypress USB to serial device */
134 static int  cypress_earthmate_startup(struct usb_serial *serial);
135 static int  cypress_hidcom_startup(struct usb_serial *serial);
136 static int  cypress_ca42v2_startup(struct usb_serial *serial);
137 static void cypress_release(struct usb_serial *serial);
138 static int  cypress_open(struct tty_struct *tty, struct usb_serial_port *port);
139 static void cypress_close(struct usb_serial_port *port);
140 static void cypress_dtr_rts(struct usb_serial_port *port, int on);
141 static int  cypress_write(struct tty_struct *tty, struct usb_serial_port *port,
142 			const unsigned char *buf, int count);
143 static void cypress_send(struct usb_serial_port *port);
144 static int  cypress_write_room(struct tty_struct *tty);
145 static int  cypress_ioctl(struct tty_struct *tty,
146 			unsigned int cmd, unsigned long arg);
147 static void cypress_set_termios(struct tty_struct *tty,
148 			struct usb_serial_port *port, struct ktermios *old);
149 static int  cypress_tiocmget(struct tty_struct *tty);
150 static int  cypress_tiocmset(struct tty_struct *tty,
151 			unsigned int set, unsigned int clear);
152 static int  cypress_chars_in_buffer(struct tty_struct *tty);
153 static void cypress_throttle(struct tty_struct *tty);
154 static void cypress_unthrottle(struct tty_struct *tty);
155 static void cypress_set_dead(struct usb_serial_port *port);
156 static void cypress_read_int_callback(struct urb *urb);
157 static void cypress_write_int_callback(struct urb *urb);
158 
159 static struct usb_serial_driver cypress_earthmate_device = {
160 	.driver = {
161 		.owner =		THIS_MODULE,
162 		.name =			"earthmate",
163 	},
164 	.description =			"DeLorme Earthmate USB",
165 	.id_table =			id_table_earthmate,
166 	.num_ports =			1,
167 	.attach =			cypress_earthmate_startup,
168 	.release =			cypress_release,
169 	.open =				cypress_open,
170 	.close =			cypress_close,
171 	.dtr_rts =			cypress_dtr_rts,
172 	.write =			cypress_write,
173 	.write_room =			cypress_write_room,
174 	.ioctl =			cypress_ioctl,
175 	.set_termios =			cypress_set_termios,
176 	.tiocmget =			cypress_tiocmget,
177 	.tiocmset =			cypress_tiocmset,
178 	.chars_in_buffer =		cypress_chars_in_buffer,
179 	.throttle =		 	cypress_throttle,
180 	.unthrottle =			cypress_unthrottle,
181 	.read_int_callback =		cypress_read_int_callback,
182 	.write_int_callback =		cypress_write_int_callback,
183 };
184 
185 static struct usb_serial_driver cypress_hidcom_device = {
186 	.driver = {
187 		.owner =		THIS_MODULE,
188 		.name =			"cyphidcom",
189 	},
190 	.description =			"HID->COM RS232 Adapter",
191 	.id_table =			id_table_cyphidcomrs232,
192 	.num_ports =			1,
193 	.attach =			cypress_hidcom_startup,
194 	.release =			cypress_release,
195 	.open =				cypress_open,
196 	.close =			cypress_close,
197 	.dtr_rts =			cypress_dtr_rts,
198 	.write =			cypress_write,
199 	.write_room =			cypress_write_room,
200 	.ioctl =			cypress_ioctl,
201 	.set_termios =			cypress_set_termios,
202 	.tiocmget =			cypress_tiocmget,
203 	.tiocmset =			cypress_tiocmset,
204 	.chars_in_buffer =		cypress_chars_in_buffer,
205 	.throttle =			cypress_throttle,
206 	.unthrottle =			cypress_unthrottle,
207 	.read_int_callback =		cypress_read_int_callback,
208 	.write_int_callback =		cypress_write_int_callback,
209 };
210 
211 static struct usb_serial_driver cypress_ca42v2_device = {
212 	.driver = {
213 		.owner =		THIS_MODULE,
214 		.name =			"nokiaca42v2",
215 	},
216 	.description =			"Nokia CA-42 V2 Adapter",
217 	.id_table =			id_table_nokiaca42v2,
218 	.num_ports =			1,
219 	.attach =			cypress_ca42v2_startup,
220 	.release =			cypress_release,
221 	.open =				cypress_open,
222 	.close =			cypress_close,
223 	.dtr_rts =			cypress_dtr_rts,
224 	.write =			cypress_write,
225 	.write_room =			cypress_write_room,
226 	.ioctl =			cypress_ioctl,
227 	.set_termios =			cypress_set_termios,
228 	.tiocmget =			cypress_tiocmget,
229 	.tiocmset =			cypress_tiocmset,
230 	.chars_in_buffer =		cypress_chars_in_buffer,
231 	.throttle =			cypress_throttle,
232 	.unthrottle =			cypress_unthrottle,
233 	.read_int_callback =		cypress_read_int_callback,
234 	.write_int_callback =		cypress_write_int_callback,
235 };
236 
237 static struct usb_serial_driver * const serial_drivers[] = {
238 	&cypress_earthmate_device, &cypress_hidcom_device,
239 	&cypress_ca42v2_device, NULL
240 };
241 
242 /*****************************************************************************
243  * Cypress serial helper functions
244  *****************************************************************************/
245 
246 
247 static int analyze_baud_rate(struct usb_serial_port *port, speed_t new_rate)
248 {
249 	struct cypress_private *priv;
250 	priv = usb_get_serial_port_data(port);
251 
252 	if (unstable_bauds)
253 		return new_rate;
254 
255 	/*
256 	 * The general purpose firmware for the Cypress M8 allows for
257 	 * a maximum speed of 57600bps (I have no idea whether DeLorme
258 	 * chose to use the general purpose firmware or not), if you
259 	 * need to modify this speed setting for your own project
260 	 * please add your own chiptype and modify the code likewise.
261 	 * The Cypress HID->COM device will work successfully up to
262 	 * 115200bps (but the actual throughput is around 3kBps).
263 	 */
264 	if (port->serial->dev->speed == USB_SPEED_LOW) {
265 		/*
266 		 * Mike Isely <isely@pobox.com> 2-Feb-2008: The
267 		 * Cypress app note that describes this mechanism
268 		 * states the the low-speed part can't handle more
269 		 * than 800 bytes/sec, in which case 4800 baud is the
270 		 * safest speed for a part like that.
271 		 */
272 		if (new_rate > 4800) {
273 			dbg("%s - failed setting baud rate, device incapable "
274 			    "speed %d", __func__, new_rate);
275 			return -1;
276 		}
277 	}
278 	switch (priv->chiptype) {
279 	case CT_EARTHMATE:
280 		if (new_rate <= 600) {
281 			/* 300 and 600 baud rates are supported under
282 			 * the generic firmware, but are not used with
283 			 * NMEA and SiRF protocols */
284 			dbg("%s - failed setting baud rate, unsupported speed "
285 			    "of %d on Earthmate GPS", __func__, new_rate);
286 			return -1;
287 		}
288 		break;
289 	default:
290 		break;
291 	}
292 	return new_rate;
293 }
294 
295 
296 /* This function can either set or retrieve the current serial line settings */
297 static int cypress_serial_control(struct tty_struct *tty,
298 	struct usb_serial_port *port, speed_t baud_rate, int data_bits,
299 	int stop_bits, int parity_enable, int parity_type, int reset,
300 	int cypress_request_type)
301 {
302 	int new_baudrate = 0, retval = 0, tries = 0;
303 	struct cypress_private *priv;
304 	u8 *feature_buffer;
305 	const unsigned int feature_len = 5;
306 	unsigned long flags;
307 
308 	dbg("%s", __func__);
309 
310 	priv = usb_get_serial_port_data(port);
311 
312 	if (!priv->comm_is_ok)
313 		return -ENODEV;
314 
315 	feature_buffer = kcalloc(feature_len, sizeof(u8), GFP_KERNEL);
316 	if (!feature_buffer)
317 		return -ENOMEM;
318 
319 	switch (cypress_request_type) {
320 	case CYPRESS_SET_CONFIG:
321 		/* 0 means 'Hang up' so doesn't change the true bit rate */
322 		new_baudrate = priv->baud_rate;
323 		if (baud_rate && baud_rate != priv->baud_rate) {
324 			dbg("%s - baud rate is changing", __func__);
325 			retval = analyze_baud_rate(port, baud_rate);
326 			if (retval >= 0) {
327 				new_baudrate = retval;
328 				dbg("%s - New baud rate set to %d",
329 				    __func__, new_baudrate);
330 			}
331 		}
332 		dbg("%s - baud rate is being sent as %d",
333 					__func__, new_baudrate);
334 
335 		/* fill the feature_buffer with new configuration */
336 		put_unaligned_le32(new_baudrate, feature_buffer);
337 		feature_buffer[4] |= data_bits;   /* assign data bits in 2 bit space ( max 3 ) */
338 		/* 1 bit gap */
339 		feature_buffer[4] |= (stop_bits << 3);   /* assign stop bits in 1 bit space */
340 		feature_buffer[4] |= (parity_enable << 4);   /* assign parity flag in 1 bit space */
341 		feature_buffer[4] |= (parity_type << 5);   /* assign parity type in 1 bit space */
342 		/* 1 bit gap */
343 		feature_buffer[4] |= (reset << 7);   /* assign reset at end of byte, 1 bit space */
344 
345 		dbg("%s - device is being sent this feature report:",
346 								__func__);
347 		dbg("%s - %02X - %02X - %02X - %02X - %02X", __func__,
348 			feature_buffer[0], feature_buffer[1],
349 			feature_buffer[2], feature_buffer[3],
350 			feature_buffer[4]);
351 
352 		do {
353 			retval = usb_control_msg(port->serial->dev,
354 					usb_sndctrlpipe(port->serial->dev, 0),
355 					HID_REQ_SET_REPORT,
356 					USB_DIR_OUT | USB_RECIP_INTERFACE | USB_TYPE_CLASS,
357 					0x0300, 0, feature_buffer,
358 					feature_len, 500);
359 
360 			if (tries++ >= 3)
361 				break;
362 
363 		} while (retval != feature_len &&
364 			 retval != -ENODEV);
365 
366 		if (retval != feature_len) {
367 			dev_err(&port->dev, "%s - failed sending serial "
368 				"line settings - %d\n", __func__, retval);
369 			cypress_set_dead(port);
370 		} else {
371 			spin_lock_irqsave(&priv->lock, flags);
372 			priv->baud_rate = new_baudrate;
373 			priv->current_config = feature_buffer[4];
374 			spin_unlock_irqrestore(&priv->lock, flags);
375 			/* If we asked for a speed change encode it */
376 			if (baud_rate)
377 				tty_encode_baud_rate(tty,
378 					new_baudrate, new_baudrate);
379 		}
380 	break;
381 	case CYPRESS_GET_CONFIG:
382 		if (priv->get_cfg_unsafe) {
383 			/* Not implemented for this device,
384 			   and if we try to do it we're likely
385 			   to crash the hardware. */
386 			retval = -ENOTTY;
387 			goto out;
388 		}
389 		dbg("%s - retreiving serial line settings", __func__);
390 		do {
391 			retval = usb_control_msg(port->serial->dev,
392 					usb_rcvctrlpipe(port->serial->dev, 0),
393 					HID_REQ_GET_REPORT,
394 					USB_DIR_IN | USB_RECIP_INTERFACE | USB_TYPE_CLASS,
395 					0x0300, 0, feature_buffer,
396 					feature_len, 500);
397 
398 			if (tries++ >= 3)
399 				break;
400 		} while (retval != feature_len
401 						&& retval != -ENODEV);
402 
403 		if (retval != feature_len) {
404 			dev_err(&port->dev, "%s - failed to retrieve serial "
405 				"line settings - %d\n", __func__, retval);
406 			cypress_set_dead(port);
407 			goto out;
408 		} else {
409 			spin_lock_irqsave(&priv->lock, flags);
410 			/* store the config in one byte, and later
411 			   use bit masks to check values */
412 			priv->current_config = feature_buffer[4];
413 			priv->baud_rate = get_unaligned_le32(feature_buffer);
414 			spin_unlock_irqrestore(&priv->lock, flags);
415 		}
416 	}
417 	spin_lock_irqsave(&priv->lock, flags);
418 	++priv->cmd_count;
419 	spin_unlock_irqrestore(&priv->lock, flags);
420 out:
421 	kfree(feature_buffer);
422 	return retval;
423 } /* cypress_serial_control */
424 
425 
426 static void cypress_set_dead(struct usb_serial_port *port)
427 {
428 	struct cypress_private *priv = usb_get_serial_port_data(port);
429 	unsigned long flags;
430 
431 	spin_lock_irqsave(&priv->lock, flags);
432 	if (!priv->comm_is_ok) {
433 		spin_unlock_irqrestore(&priv->lock, flags);
434 		return;
435 	}
436 	priv->comm_is_ok = 0;
437 	spin_unlock_irqrestore(&priv->lock, flags);
438 
439 	dev_err(&port->dev, "cypress_m8 suspending failing port %d - "
440 		"interval might be too short\n", port->number);
441 }
442 
443 
444 /*****************************************************************************
445  * Cypress serial driver functions
446  *****************************************************************************/
447 
448 
449 static int generic_startup(struct usb_serial *serial)
450 {
451 	struct cypress_private *priv;
452 	struct usb_serial_port *port = serial->port[0];
453 
454 	dbg("%s - port %d", __func__, port->number);
455 
456 	priv = kzalloc(sizeof(struct cypress_private), GFP_KERNEL);
457 	if (!priv)
458 		return -ENOMEM;
459 
460 	priv->comm_is_ok = !0;
461 	spin_lock_init(&priv->lock);
462 	if (kfifo_alloc(&priv->write_fifo, CYPRESS_BUF_SIZE, GFP_KERNEL)) {
463 		kfree(priv);
464 		return -ENOMEM;
465 	}
466 	init_waitqueue_head(&priv->delta_msr_wait);
467 
468 	usb_reset_configuration(serial->dev);
469 
470 	priv->cmd_ctrl = 0;
471 	priv->line_control = 0;
472 	priv->termios_initialized = 0;
473 	priv->rx_flags = 0;
474 	/* Default packet format setting is determined by packet size.
475 	   Anything with a size larger then 9 must have a separate
476 	   count field since the 3 bit count field is otherwise too
477 	   small.  Otherwise we can use the slightly more compact
478 	   format.  This is in accordance with the cypress_m8 serial
479 	   converter app note. */
480 	if (port->interrupt_out_size > 9)
481 		priv->pkt_fmt = packet_format_1;
482 	else
483 		priv->pkt_fmt = packet_format_2;
484 
485 	if (interval > 0) {
486 		priv->write_urb_interval = interval;
487 		priv->read_urb_interval = interval;
488 		dbg("%s - port %d read & write intervals forced to %d",
489 		    __func__, port->number, interval);
490 	} else {
491 		priv->write_urb_interval = port->interrupt_out_urb->interval;
492 		priv->read_urb_interval = port->interrupt_in_urb->interval;
493 		dbg("%s - port %d intervals: read=%d write=%d",
494 		    __func__, port->number,
495 		    priv->read_urb_interval, priv->write_urb_interval);
496 	}
497 	usb_set_serial_port_data(port, priv);
498 
499 	return 0;
500 }
501 
502 
503 static int cypress_earthmate_startup(struct usb_serial *serial)
504 {
505 	struct cypress_private *priv;
506 	struct usb_serial_port *port = serial->port[0];
507 
508 	dbg("%s", __func__);
509 
510 	if (generic_startup(serial)) {
511 		dbg("%s - Failed setting up port %d", __func__,
512 				port->number);
513 		return 1;
514 	}
515 
516 	priv = usb_get_serial_port_data(port);
517 	priv->chiptype = CT_EARTHMATE;
518 	/* All Earthmate devices use the separated-count packet
519 	   format!  Idiotic. */
520 	priv->pkt_fmt = packet_format_1;
521 	if (serial->dev->descriptor.idProduct !=
522 				cpu_to_le16(PRODUCT_ID_EARTHMATEUSB)) {
523 		/* The old original USB Earthmate seemed able to
524 		   handle GET_CONFIG requests; everything they've
525 		   produced since that time crashes if this command is
526 		   attempted :-( */
527 		dbg("%s - Marking this device as unsafe for GET_CONFIG "
528 		    "commands", __func__);
529 		priv->get_cfg_unsafe = !0;
530 	}
531 
532 	return 0;
533 } /* cypress_earthmate_startup */
534 
535 
536 static int cypress_hidcom_startup(struct usb_serial *serial)
537 {
538 	struct cypress_private *priv;
539 
540 	dbg("%s", __func__);
541 
542 	if (generic_startup(serial)) {
543 		dbg("%s - Failed setting up port %d", __func__,
544 				serial->port[0]->number);
545 		return 1;
546 	}
547 
548 	priv = usb_get_serial_port_data(serial->port[0]);
549 	priv->chiptype = CT_CYPHIDCOM;
550 
551 	return 0;
552 } /* cypress_hidcom_startup */
553 
554 
555 static int cypress_ca42v2_startup(struct usb_serial *serial)
556 {
557 	struct cypress_private *priv;
558 
559 	dbg("%s", __func__);
560 
561 	if (generic_startup(serial)) {
562 		dbg("%s - Failed setting up port %d", __func__,
563 				serial->port[0]->number);
564 		return 1;
565 	}
566 
567 	priv = usb_get_serial_port_data(serial->port[0]);
568 	priv->chiptype = CT_CA42V2;
569 
570 	return 0;
571 } /* cypress_ca42v2_startup */
572 
573 
574 static void cypress_release(struct usb_serial *serial)
575 {
576 	struct cypress_private *priv;
577 
578 	dbg("%s - port %d", __func__, serial->port[0]->number);
579 
580 	/* all open ports are closed at this point */
581 
582 	priv = usb_get_serial_port_data(serial->port[0]);
583 
584 	if (priv) {
585 		kfifo_free(&priv->write_fifo);
586 		kfree(priv);
587 	}
588 }
589 
590 
591 static int cypress_open(struct tty_struct *tty, struct usb_serial_port *port)
592 {
593 	struct cypress_private *priv = usb_get_serial_port_data(port);
594 	struct usb_serial *serial = port->serial;
595 	unsigned long flags;
596 	int result = 0;
597 
598 	dbg("%s - port %d", __func__, port->number);
599 
600 	if (!priv->comm_is_ok)
601 		return -EIO;
602 
603 	/* clear halts before open */
604 	usb_clear_halt(serial->dev, 0x81);
605 	usb_clear_halt(serial->dev, 0x02);
606 
607 	spin_lock_irqsave(&priv->lock, flags);
608 	/* reset read/write statistics */
609 	priv->bytes_in = 0;
610 	priv->bytes_out = 0;
611 	priv->cmd_count = 0;
612 	priv->rx_flags = 0;
613 	spin_unlock_irqrestore(&priv->lock, flags);
614 
615 	/* Set termios */
616 	cypress_send(port);
617 
618 	if (tty)
619 		cypress_set_termios(tty, port, &priv->tmp_termios);
620 
621 	/* setup the port and start reading from the device */
622 	if (!port->interrupt_in_urb) {
623 		dev_err(&port->dev, "%s - interrupt_in_urb is empty!\n",
624 			__func__);
625 		return -1;
626 	}
627 
628 	usb_fill_int_urb(port->interrupt_in_urb, serial->dev,
629 		usb_rcvintpipe(serial->dev, port->interrupt_in_endpointAddress),
630 		port->interrupt_in_urb->transfer_buffer,
631 		port->interrupt_in_urb->transfer_buffer_length,
632 		cypress_read_int_callback, port, priv->read_urb_interval);
633 	result = usb_submit_urb(port->interrupt_in_urb, GFP_KERNEL);
634 
635 	if (result) {
636 		dev_err(&port->dev,
637 			"%s - failed submitting read urb, error %d\n",
638 							__func__, result);
639 		cypress_set_dead(port);
640 	}
641 	port->port.drain_delay = 256;
642 	return result;
643 } /* cypress_open */
644 
645 static void cypress_dtr_rts(struct usb_serial_port *port, int on)
646 {
647 	struct cypress_private *priv = usb_get_serial_port_data(port);
648 	/* drop dtr and rts */
649 	spin_lock_irq(&priv->lock);
650 	if (on == 0)
651 		priv->line_control = 0;
652 	else
653 		priv->line_control = CONTROL_DTR | CONTROL_RTS;
654 	priv->cmd_ctrl = 1;
655 	spin_unlock_irq(&priv->lock);
656 	cypress_write(NULL, port, NULL, 0);
657 }
658 
659 static void cypress_close(struct usb_serial_port *port)
660 {
661 	struct cypress_private *priv = usb_get_serial_port_data(port);
662 	unsigned long flags;
663 
664 	dbg("%s - port %d", __func__, port->number);
665 
666 	/* writing is potentially harmful, lock must be taken */
667 	mutex_lock(&port->serial->disc_mutex);
668 	if (port->serial->disconnected) {
669 		mutex_unlock(&port->serial->disc_mutex);
670 		return;
671 	}
672 	spin_lock_irqsave(&priv->lock, flags);
673 	kfifo_reset_out(&priv->write_fifo);
674 	spin_unlock_irqrestore(&priv->lock, flags);
675 
676 	dbg("%s - stopping urbs", __func__);
677 	usb_kill_urb(port->interrupt_in_urb);
678 	usb_kill_urb(port->interrupt_out_urb);
679 
680 	if (stats)
681 		dev_info(&port->dev, "Statistics: %d Bytes In | %d Bytes Out | %d Commands Issued\n",
682 			priv->bytes_in, priv->bytes_out, priv->cmd_count);
683 	mutex_unlock(&port->serial->disc_mutex);
684 } /* cypress_close */
685 
686 
687 static int cypress_write(struct tty_struct *tty, struct usb_serial_port *port,
688 					const unsigned char *buf, int count)
689 {
690 	struct cypress_private *priv = usb_get_serial_port_data(port);
691 
692 	dbg("%s - port %d, %d bytes", __func__, port->number, count);
693 
694 	/* line control commands, which need to be executed immediately,
695 	   are not put into the buffer for obvious reasons.
696 	 */
697 	if (priv->cmd_ctrl) {
698 		count = 0;
699 		goto finish;
700 	}
701 
702 	if (!count)
703 		return count;
704 
705 	count = kfifo_in_locked(&priv->write_fifo, buf, count, &priv->lock);
706 
707 finish:
708 	cypress_send(port);
709 
710 	return count;
711 } /* cypress_write */
712 
713 
714 static void cypress_send(struct usb_serial_port *port)
715 {
716 	int count = 0, result, offset, actual_size;
717 	struct cypress_private *priv = usb_get_serial_port_data(port);
718 	unsigned long flags;
719 
720 	if (!priv->comm_is_ok)
721 		return;
722 
723 	dbg("%s - port %d", __func__, port->number);
724 	dbg("%s - interrupt out size is %d", __func__,
725 						port->interrupt_out_size);
726 
727 	spin_lock_irqsave(&priv->lock, flags);
728 	if (priv->write_urb_in_use) {
729 		dbg("%s - can't write, urb in use", __func__);
730 		spin_unlock_irqrestore(&priv->lock, flags);
731 		return;
732 	}
733 	spin_unlock_irqrestore(&priv->lock, flags);
734 
735 	/* clear buffer */
736 	memset(port->interrupt_out_urb->transfer_buffer, 0,
737 						port->interrupt_out_size);
738 
739 	spin_lock_irqsave(&priv->lock, flags);
740 	switch (priv->pkt_fmt) {
741 	default:
742 	case packet_format_1:
743 		/* this is for the CY7C64013... */
744 		offset = 2;
745 		port->interrupt_out_buffer[0] = priv->line_control;
746 		break;
747 	case packet_format_2:
748 		/* this is for the CY7C63743... */
749 		offset = 1;
750 		port->interrupt_out_buffer[0] = priv->line_control;
751 		break;
752 	}
753 
754 	if (priv->line_control & CONTROL_RESET)
755 		priv->line_control &= ~CONTROL_RESET;
756 
757 	if (priv->cmd_ctrl) {
758 		priv->cmd_count++;
759 		dbg("%s - line control command being issued", __func__);
760 		spin_unlock_irqrestore(&priv->lock, flags);
761 		goto send;
762 	} else
763 		spin_unlock_irqrestore(&priv->lock, flags);
764 
765 	count = kfifo_out_locked(&priv->write_fifo,
766 					&port->interrupt_out_buffer[offset],
767 					port->interrupt_out_size - offset,
768 					&priv->lock);
769 	if (count == 0)
770 		return;
771 
772 	switch (priv->pkt_fmt) {
773 	default:
774 	case packet_format_1:
775 		port->interrupt_out_buffer[1] = count;
776 		break;
777 	case packet_format_2:
778 		port->interrupt_out_buffer[0] |= count;
779 	}
780 
781 	dbg("%s - count is %d", __func__, count);
782 
783 send:
784 	spin_lock_irqsave(&priv->lock, flags);
785 	priv->write_urb_in_use = 1;
786 	spin_unlock_irqrestore(&priv->lock, flags);
787 
788 	if (priv->cmd_ctrl)
789 		actual_size = 1;
790 	else
791 		actual_size = count +
792 			      (priv->pkt_fmt == packet_format_1 ? 2 : 1);
793 
794 	usb_serial_debug_data(debug, &port->dev, __func__,
795 		port->interrupt_out_size,
796 		port->interrupt_out_urb->transfer_buffer);
797 
798 	usb_fill_int_urb(port->interrupt_out_urb, port->serial->dev,
799 		usb_sndintpipe(port->serial->dev, port->interrupt_out_endpointAddress),
800 		port->interrupt_out_buffer, port->interrupt_out_size,
801 		cypress_write_int_callback, port, priv->write_urb_interval);
802 	result = usb_submit_urb(port->interrupt_out_urb, GFP_ATOMIC);
803 	if (result) {
804 		dev_err_console(port,
805 				"%s - failed submitting write urb, error %d\n",
806 							__func__, result);
807 		priv->write_urb_in_use = 0;
808 		cypress_set_dead(port);
809 	}
810 
811 	spin_lock_irqsave(&priv->lock, flags);
812 	if (priv->cmd_ctrl)
813 		priv->cmd_ctrl = 0;
814 
815 	/* do not count the line control and size bytes */
816 	priv->bytes_out += count;
817 	spin_unlock_irqrestore(&priv->lock, flags);
818 
819 	usb_serial_port_softint(port);
820 } /* cypress_send */
821 
822 
823 /* returns how much space is available in the soft buffer */
824 static int cypress_write_room(struct tty_struct *tty)
825 {
826 	struct usb_serial_port *port = tty->driver_data;
827 	struct cypress_private *priv = usb_get_serial_port_data(port);
828 	int room = 0;
829 	unsigned long flags;
830 
831 	dbg("%s - port %d", __func__, port->number);
832 
833 	spin_lock_irqsave(&priv->lock, flags);
834 	room = kfifo_avail(&priv->write_fifo);
835 	spin_unlock_irqrestore(&priv->lock, flags);
836 
837 	dbg("%s - returns %d", __func__, room);
838 	return room;
839 }
840 
841 
842 static int cypress_tiocmget(struct tty_struct *tty)
843 {
844 	struct usb_serial_port *port = tty->driver_data;
845 	struct cypress_private *priv = usb_get_serial_port_data(port);
846 	__u8 status, control;
847 	unsigned int result = 0;
848 	unsigned long flags;
849 
850 	dbg("%s - port %d", __func__, port->number);
851 
852 	spin_lock_irqsave(&priv->lock, flags);
853 	control = priv->line_control;
854 	status = priv->current_status;
855 	spin_unlock_irqrestore(&priv->lock, flags);
856 
857 	result = ((control & CONTROL_DTR)        ? TIOCM_DTR : 0)
858 		| ((control & CONTROL_RTS)       ? TIOCM_RTS : 0)
859 		| ((status & UART_CTS)        ? TIOCM_CTS : 0)
860 		| ((status & UART_DSR)        ? TIOCM_DSR : 0)
861 		| ((status & UART_RI)         ? TIOCM_RI  : 0)
862 		| ((status & UART_CD)         ? TIOCM_CD  : 0);
863 
864 	dbg("%s - result = %x", __func__, result);
865 
866 	return result;
867 }
868 
869 
870 static int cypress_tiocmset(struct tty_struct *tty,
871 			       unsigned int set, unsigned int clear)
872 {
873 	struct usb_serial_port *port = tty->driver_data;
874 	struct cypress_private *priv = usb_get_serial_port_data(port);
875 	unsigned long flags;
876 
877 	dbg("%s - port %d", __func__, port->number);
878 
879 	spin_lock_irqsave(&priv->lock, flags);
880 	if (set & TIOCM_RTS)
881 		priv->line_control |= CONTROL_RTS;
882 	if (set & TIOCM_DTR)
883 		priv->line_control |= CONTROL_DTR;
884 	if (clear & TIOCM_RTS)
885 		priv->line_control &= ~CONTROL_RTS;
886 	if (clear & TIOCM_DTR)
887 		priv->line_control &= ~CONTROL_DTR;
888 	priv->cmd_ctrl = 1;
889 	spin_unlock_irqrestore(&priv->lock, flags);
890 
891 	return cypress_write(tty, port, NULL, 0);
892 }
893 
894 
895 static int cypress_ioctl(struct tty_struct *tty,
896 					unsigned int cmd, unsigned long arg)
897 {
898 	struct usb_serial_port *port = tty->driver_data;
899 	struct cypress_private *priv = usb_get_serial_port_data(port);
900 
901 	dbg("%s - port %d, cmd 0x%.4x", __func__, port->number, cmd);
902 
903 	switch (cmd) {
904 	/* This code comes from drivers/char/serial.c and ftdi_sio.c */
905 	case TIOCMIWAIT:
906 		while (priv != NULL) {
907 			interruptible_sleep_on(&priv->delta_msr_wait);
908 			/* see if a signal did it */
909 			if (signal_pending(current))
910 				return -ERESTARTSYS;
911 			else {
912 				char diff = priv->diff_status;
913 				if (diff == 0)
914 					return -EIO; /* no change => error */
915 
916 				/* consume all events */
917 				priv->diff_status = 0;
918 
919 				/* return 0 if caller wanted to know about
920 				   these bits */
921 				if (((arg & TIOCM_RNG) && (diff & UART_RI)) ||
922 				    ((arg & TIOCM_DSR) && (diff & UART_DSR)) ||
923 				    ((arg & TIOCM_CD) && (diff & UART_CD)) ||
924 				    ((arg & TIOCM_CTS) && (diff & UART_CTS)))
925 					return 0;
926 				/* otherwise caller can't care less about what
927 				 * happened, and so we continue to wait for
928 				 * more events.
929 				 */
930 			}
931 		}
932 		return 0;
933 	default:
934 		break;
935 	}
936 	dbg("%s - arg not supported - it was 0x%04x - check include/asm/ioctls.h", __func__, cmd);
937 	return -ENOIOCTLCMD;
938 } /* cypress_ioctl */
939 
940 
941 static void cypress_set_termios(struct tty_struct *tty,
942 	struct usb_serial_port *port, struct ktermios *old_termios)
943 {
944 	struct cypress_private *priv = usb_get_serial_port_data(port);
945 	int data_bits, stop_bits, parity_type, parity_enable;
946 	unsigned cflag, iflag;
947 	unsigned long flags;
948 	__u8 oldlines;
949 	int linechange = 0;
950 
951 	dbg("%s - port %d", __func__, port->number);
952 
953 	spin_lock_irqsave(&priv->lock, flags);
954 	/* We can't clean this one up as we don't know the device type
955 	   early enough */
956 	if (!priv->termios_initialized) {
957 		if (priv->chiptype == CT_EARTHMATE) {
958 			*(tty->termios) = tty_std_termios;
959 			tty->termios->c_cflag = B4800 | CS8 | CREAD | HUPCL |
960 				CLOCAL;
961 			tty->termios->c_ispeed = 4800;
962 			tty->termios->c_ospeed = 4800;
963 		} else if (priv->chiptype == CT_CYPHIDCOM) {
964 			*(tty->termios) = tty_std_termios;
965 			tty->termios->c_cflag = B9600 | CS8 | CREAD | HUPCL |
966 				CLOCAL;
967 			tty->termios->c_ispeed = 9600;
968 			tty->termios->c_ospeed = 9600;
969 		} else if (priv->chiptype == CT_CA42V2) {
970 			*(tty->termios) = tty_std_termios;
971 			tty->termios->c_cflag = B9600 | CS8 | CREAD | HUPCL |
972 				CLOCAL;
973 			tty->termios->c_ispeed = 9600;
974 			tty->termios->c_ospeed = 9600;
975 		}
976 		priv->termios_initialized = 1;
977 	}
978 	spin_unlock_irqrestore(&priv->lock, flags);
979 
980 	/* Unsupported features need clearing */
981 	tty->termios->c_cflag &= ~(CMSPAR|CRTSCTS);
982 
983 	cflag = tty->termios->c_cflag;
984 	iflag = tty->termios->c_iflag;
985 
986 	/* check if there are new settings */
987 	if (old_termios) {
988 		spin_lock_irqsave(&priv->lock, flags);
989 		priv->tmp_termios = *(tty->termios);
990 		spin_unlock_irqrestore(&priv->lock, flags);
991 	}
992 
993 	/* set number of data bits, parity, stop bits */
994 	/* when parity is disabled the parity type bit is ignored */
995 
996 	/* 1 means 2 stop bits, 0 means 1 stop bit */
997 	stop_bits = cflag & CSTOPB ? 1 : 0;
998 
999 	if (cflag & PARENB) {
1000 		parity_enable = 1;
1001 		/* 1 means odd parity, 0 means even parity */
1002 		parity_type = cflag & PARODD ? 1 : 0;
1003 	} else
1004 		parity_enable = parity_type = 0;
1005 
1006 	switch (cflag & CSIZE) {
1007 	case CS5:
1008 		data_bits = 0;
1009 		break;
1010 	case CS6:
1011 		data_bits = 1;
1012 		break;
1013 	case CS7:
1014 		data_bits = 2;
1015 		break;
1016 	case CS8:
1017 		data_bits = 3;
1018 		break;
1019 	default:
1020 		dev_err(&port->dev, "%s - CSIZE was set, but not CS5-CS8\n",
1021 			__func__);
1022 		data_bits = 3;
1023 	}
1024 	spin_lock_irqsave(&priv->lock, flags);
1025 	oldlines = priv->line_control;
1026 	if ((cflag & CBAUD) == B0) {
1027 		/* drop dtr and rts */
1028 		dbg("%s - dropping the lines, baud rate 0bps", __func__);
1029 		priv->line_control &= ~(CONTROL_DTR | CONTROL_RTS);
1030 	} else
1031 		priv->line_control = (CONTROL_DTR | CONTROL_RTS);
1032 	spin_unlock_irqrestore(&priv->lock, flags);
1033 
1034 	dbg("%s - sending %d stop_bits, %d parity_enable, %d parity_type, "
1035 			"%d data_bits (+5)", __func__, stop_bits,
1036 			parity_enable, parity_type, data_bits);
1037 
1038 	cypress_serial_control(tty, port, tty_get_baud_rate(tty),
1039 			data_bits, stop_bits,
1040 			parity_enable, parity_type,
1041 			0, CYPRESS_SET_CONFIG);
1042 
1043 	/* we perform a CYPRESS_GET_CONFIG so that the current settings are
1044 	 * filled into the private structure this should confirm that all is
1045 	 * working if it returns what we just set */
1046 	cypress_serial_control(tty, port, 0, 0, 0, 0, 0, 0, CYPRESS_GET_CONFIG);
1047 
1048 	/* Here we can define custom tty settings for devices; the main tty
1049 	 * termios flag base comes from empeg.c */
1050 
1051 	spin_lock_irqsave(&priv->lock, flags);
1052 	if (priv->chiptype == CT_EARTHMATE && priv->baud_rate == 4800) {
1053 		dbg("Using custom termios settings for a baud rate of "
1054 				"4800bps.");
1055 		/* define custom termios settings for NMEA protocol */
1056 
1057 		tty->termios->c_iflag /* input modes - */
1058 			&= ~(IGNBRK  /* disable ignore break */
1059 			| BRKINT     /* disable break causes interrupt */
1060 			| PARMRK     /* disable mark parity errors */
1061 			| ISTRIP     /* disable clear high bit of input char */
1062 			| INLCR      /* disable translate NL to CR */
1063 			| IGNCR      /* disable ignore CR */
1064 			| ICRNL      /* disable translate CR to NL */
1065 			| IXON);     /* disable enable XON/XOFF flow control */
1066 
1067 		tty->termios->c_oflag /* output modes */
1068 			&= ~OPOST;    /* disable postprocess output char */
1069 
1070 		tty->termios->c_lflag /* line discipline modes */
1071 			&= ~(ECHO     /* disable echo input characters */
1072 			| ECHONL      /* disable echo new line */
1073 			| ICANON      /* disable erase, kill, werase, and rprnt
1074 					 special characters */
1075 			| ISIG        /* disable interrupt, quit, and suspend
1076 					 special characters */
1077 			| IEXTEN);    /* disable non-POSIX special characters */
1078 	} /* CT_CYPHIDCOM: Application should handle this for device */
1079 
1080 	linechange = (priv->line_control != oldlines);
1081 	spin_unlock_irqrestore(&priv->lock, flags);
1082 
1083 	/* if necessary, set lines */
1084 	if (linechange) {
1085 		priv->cmd_ctrl = 1;
1086 		cypress_write(tty, port, NULL, 0);
1087 	}
1088 } /* cypress_set_termios */
1089 
1090 
1091 /* returns amount of data still left in soft buffer */
1092 static int cypress_chars_in_buffer(struct tty_struct *tty)
1093 {
1094 	struct usb_serial_port *port = tty->driver_data;
1095 	struct cypress_private *priv = usb_get_serial_port_data(port);
1096 	int chars = 0;
1097 	unsigned long flags;
1098 
1099 	dbg("%s - port %d", __func__, port->number);
1100 
1101 	spin_lock_irqsave(&priv->lock, flags);
1102 	chars = kfifo_len(&priv->write_fifo);
1103 	spin_unlock_irqrestore(&priv->lock, flags);
1104 
1105 	dbg("%s - returns %d", __func__, chars);
1106 	return chars;
1107 }
1108 
1109 
1110 static void cypress_throttle(struct tty_struct *tty)
1111 {
1112 	struct usb_serial_port *port = tty->driver_data;
1113 	struct cypress_private *priv = usb_get_serial_port_data(port);
1114 
1115 	dbg("%s - port %d", __func__, port->number);
1116 
1117 	spin_lock_irq(&priv->lock);
1118 	priv->rx_flags = THROTTLED;
1119 	spin_unlock_irq(&priv->lock);
1120 }
1121 
1122 
1123 static void cypress_unthrottle(struct tty_struct *tty)
1124 {
1125 	struct usb_serial_port *port = tty->driver_data;
1126 	struct cypress_private *priv = usb_get_serial_port_data(port);
1127 	int actually_throttled, result;
1128 
1129 	dbg("%s - port %d", __func__, port->number);
1130 
1131 	spin_lock_irq(&priv->lock);
1132 	actually_throttled = priv->rx_flags & ACTUALLY_THROTTLED;
1133 	priv->rx_flags = 0;
1134 	spin_unlock_irq(&priv->lock);
1135 
1136 	if (!priv->comm_is_ok)
1137 		return;
1138 
1139 	if (actually_throttled) {
1140 		result = usb_submit_urb(port->interrupt_in_urb, GFP_KERNEL);
1141 		if (result) {
1142 			dev_err(&port->dev, "%s - failed submitting read urb, "
1143 					"error %d\n", __func__, result);
1144 			cypress_set_dead(port);
1145 		}
1146 	}
1147 }
1148 
1149 
1150 static void cypress_read_int_callback(struct urb *urb)
1151 {
1152 	struct usb_serial_port *port = urb->context;
1153 	struct cypress_private *priv = usb_get_serial_port_data(port);
1154 	struct tty_struct *tty;
1155 	unsigned char *data = urb->transfer_buffer;
1156 	unsigned long flags;
1157 	char tty_flag = TTY_NORMAL;
1158 	int havedata = 0;
1159 	int bytes = 0;
1160 	int result;
1161 	int i = 0;
1162 	int status = urb->status;
1163 
1164 	dbg("%s - port %d", __func__, port->number);
1165 
1166 	switch (status) {
1167 	case 0: /* success */
1168 		break;
1169 	case -ECONNRESET:
1170 	case -ENOENT:
1171 	case -ESHUTDOWN:
1172 		/* precursor to disconnect so just go away */
1173 		return;
1174 	case -EPIPE:
1175 		/* Can't call usb_clear_halt while in_interrupt */
1176 		/* FALLS THROUGH */
1177 	default:
1178 		/* something ugly is going on... */
1179 		dev_err(&urb->dev->dev,
1180 			"%s - unexpected nonzero read status received: %d\n",
1181 							__func__, status);
1182 		cypress_set_dead(port);
1183 		return;
1184 	}
1185 
1186 	spin_lock_irqsave(&priv->lock, flags);
1187 	if (priv->rx_flags & THROTTLED) {
1188 		dbg("%s - now throttling", __func__);
1189 		priv->rx_flags |= ACTUALLY_THROTTLED;
1190 		spin_unlock_irqrestore(&priv->lock, flags);
1191 		return;
1192 	}
1193 	spin_unlock_irqrestore(&priv->lock, flags);
1194 
1195 	tty = tty_port_tty_get(&port->port);
1196 	if (!tty) {
1197 		dbg("%s - bad tty pointer - exiting", __func__);
1198 		return;
1199 	}
1200 
1201 	spin_lock_irqsave(&priv->lock, flags);
1202 	result = urb->actual_length;
1203 	switch (priv->pkt_fmt) {
1204 	default:
1205 	case packet_format_1:
1206 		/* This is for the CY7C64013... */
1207 		priv->current_status = data[0] & 0xF8;
1208 		bytes = data[1] + 2;
1209 		i = 2;
1210 		if (bytes > 2)
1211 			havedata = 1;
1212 		break;
1213 	case packet_format_2:
1214 		/* This is for the CY7C63743... */
1215 		priv->current_status = data[0] & 0xF8;
1216 		bytes = (data[0] & 0x07) + 1;
1217 		i = 1;
1218 		if (bytes > 1)
1219 			havedata = 1;
1220 		break;
1221 	}
1222 	spin_unlock_irqrestore(&priv->lock, flags);
1223 	if (result < bytes) {
1224 		dbg("%s - wrong packet size - received %d bytes but packet "
1225 		    "said %d bytes", __func__, result, bytes);
1226 		goto continue_read;
1227 	}
1228 
1229 	usb_serial_debug_data(debug, &port->dev, __func__,
1230 						urb->actual_length, data);
1231 
1232 	spin_lock_irqsave(&priv->lock, flags);
1233 	/* check to see if status has changed */
1234 	if (priv->current_status != priv->prev_status) {
1235 		priv->diff_status |= priv->current_status ^
1236 			priv->prev_status;
1237 		wake_up_interruptible(&priv->delta_msr_wait);
1238 		priv->prev_status = priv->current_status;
1239 	}
1240 	spin_unlock_irqrestore(&priv->lock, flags);
1241 
1242 	/* hangup, as defined in acm.c... this might be a bad place for it
1243 	 * though */
1244 	if (tty && !(tty->termios->c_cflag & CLOCAL) &&
1245 			!(priv->current_status & UART_CD)) {
1246 		dbg("%s - calling hangup", __func__);
1247 		tty_hangup(tty);
1248 		goto continue_read;
1249 	}
1250 
1251 	/* There is one error bit... I'm assuming it is a parity error
1252 	 * indicator as the generic firmware will set this bit to 1 if a
1253 	 * parity error occurs.
1254 	 * I can not find reference to any other error events. */
1255 	spin_lock_irqsave(&priv->lock, flags);
1256 	if (priv->current_status & CYP_ERROR) {
1257 		spin_unlock_irqrestore(&priv->lock, flags);
1258 		tty_flag = TTY_PARITY;
1259 		dbg("%s - Parity Error detected", __func__);
1260 	} else
1261 		spin_unlock_irqrestore(&priv->lock, flags);
1262 
1263 	/* process read if there is data other than line status */
1264 	if (tty && bytes > i) {
1265 		tty_insert_flip_string_fixed_flag(tty, data + i,
1266 				tty_flag, bytes - i);
1267 		tty_flip_buffer_push(tty);
1268 	}
1269 
1270 	spin_lock_irqsave(&priv->lock, flags);
1271 	/* control and status byte(s) are also counted */
1272 	priv->bytes_in += bytes;
1273 	spin_unlock_irqrestore(&priv->lock, flags);
1274 
1275 continue_read:
1276 	tty_kref_put(tty);
1277 
1278 	/* Continue trying to always read */
1279 
1280 	if (priv->comm_is_ok) {
1281 		usb_fill_int_urb(port->interrupt_in_urb, port->serial->dev,
1282 				usb_rcvintpipe(port->serial->dev,
1283 					port->interrupt_in_endpointAddress),
1284 				port->interrupt_in_urb->transfer_buffer,
1285 				port->interrupt_in_urb->transfer_buffer_length,
1286 				cypress_read_int_callback, port,
1287 				priv->read_urb_interval);
1288 		result = usb_submit_urb(port->interrupt_in_urb, GFP_ATOMIC);
1289 		if (result && result != -EPERM) {
1290 			dev_err(&urb->dev->dev, "%s - failed resubmitting "
1291 					"read urb, error %d\n", __func__,
1292 					result);
1293 			cypress_set_dead(port);
1294 		}
1295 	}
1296 } /* cypress_read_int_callback */
1297 
1298 
1299 static void cypress_write_int_callback(struct urb *urb)
1300 {
1301 	struct usb_serial_port *port = urb->context;
1302 	struct cypress_private *priv = usb_get_serial_port_data(port);
1303 	int result;
1304 	int status = urb->status;
1305 
1306 	dbg("%s - port %d", __func__, port->number);
1307 
1308 	switch (status) {
1309 	case 0:
1310 		/* success */
1311 		break;
1312 	case -ECONNRESET:
1313 	case -ENOENT:
1314 	case -ESHUTDOWN:
1315 		/* this urb is terminated, clean up */
1316 		dbg("%s - urb shutting down with status: %d",
1317 						__func__, status);
1318 		priv->write_urb_in_use = 0;
1319 		return;
1320 	case -EPIPE: /* no break needed; clear halt and resubmit */
1321 		if (!priv->comm_is_ok)
1322 			break;
1323 		usb_clear_halt(port->serial->dev, 0x02);
1324 		/* error in the urb, so we have to resubmit it */
1325 		dbg("%s - nonzero write bulk status received: %d",
1326 			__func__, status);
1327 		port->interrupt_out_urb->transfer_buffer_length = 1;
1328 		result = usb_submit_urb(port->interrupt_out_urb, GFP_ATOMIC);
1329 		if (!result)
1330 			return;
1331 		dev_err(&urb->dev->dev,
1332 			"%s - failed resubmitting write urb, error %d\n",
1333 							__func__, result);
1334 		cypress_set_dead(port);
1335 		break;
1336 	default:
1337 		dev_err(&urb->dev->dev,
1338 			 "%s - unexpected nonzero write status received: %d\n",
1339 							__func__, status);
1340 		cypress_set_dead(port);
1341 		break;
1342 	}
1343 	priv->write_urb_in_use = 0;
1344 
1345 	/* send any buffered data */
1346 	cypress_send(port);
1347 }
1348 
1349 module_usb_serial_driver(cypress_driver, serial_drivers);
1350 
1351 MODULE_AUTHOR(DRIVER_AUTHOR);
1352 MODULE_DESCRIPTION(DRIVER_DESC);
1353 MODULE_VERSION(DRIVER_VERSION);
1354 MODULE_LICENSE("GPL");
1355 
1356 module_param(debug, bool, S_IRUGO | S_IWUSR);
1357 MODULE_PARM_DESC(debug, "Debug enabled or not");
1358 module_param(stats, bool, S_IRUGO | S_IWUSR);
1359 MODULE_PARM_DESC(stats, "Enable statistics or not");
1360 module_param(interval, int, S_IRUGO | S_IWUSR);
1361 MODULE_PARM_DESC(interval, "Overrides interrupt interval");
1362 module_param(unstable_bauds, bool, S_IRUGO | S_IWUSR);
1363 MODULE_PARM_DESC(unstable_bauds, "Allow unstable baud rates");
1364