xref: /linux/drivers/usb/serial/cypress_m8.c (revision e5c86679d5e864947a52fb31e45a425dea3e7fa9)
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/slab.h>
31 #include <linux/tty.h>
32 #include <linux/tty_driver.h>
33 #include <linux/tty_flip.h>
34 #include <linux/module.h>
35 #include <linux/moduleparam.h>
36 #include <linux/spinlock.h>
37 #include <linux/usb.h>
38 #include <linux/usb/serial.h>
39 #include <linux/serial.h>
40 #include <linux/kfifo.h>
41 #include <linux/delay.h>
42 #include <linux/uaccess.h>
43 #include <asm/unaligned.h>
44 
45 #include "cypress_m8.h"
46 
47 
48 static bool stats;
49 static int interval;
50 static bool unstable_bauds;
51 
52 #define DRIVER_AUTHOR "Lonnie Mendez <dignome@gmail.com>, Neil Whelchel <koyama@firstlight.net>"
53 #define DRIVER_DESC "Cypress USB to Serial Driver"
54 
55 /* write buffer size defines */
56 #define CYPRESS_BUF_SIZE	1024
57 
58 static const struct usb_device_id id_table_earthmate[] = {
59 	{ USB_DEVICE(VENDOR_ID_DELORME, PRODUCT_ID_EARTHMATEUSB) },
60 	{ USB_DEVICE(VENDOR_ID_DELORME, PRODUCT_ID_EARTHMATEUSB_LT20) },
61 	{ }						/* Terminating entry */
62 };
63 
64 static const struct usb_device_id id_table_cyphidcomrs232[] = {
65 	{ USB_DEVICE(VENDOR_ID_CYPRESS, PRODUCT_ID_CYPHIDCOM) },
66 	{ USB_DEVICE(VENDOR_ID_POWERCOM, PRODUCT_ID_UPS) },
67 	{ USB_DEVICE(VENDOR_ID_FRWD, PRODUCT_ID_CYPHIDCOM_FRWD) },
68 	{ }						/* Terminating entry */
69 };
70 
71 static const struct usb_device_id id_table_nokiaca42v2[] = {
72 	{ USB_DEVICE(VENDOR_ID_DAZZLE, PRODUCT_ID_CA42) },
73 	{ }						/* Terminating entry */
74 };
75 
76 static const struct usb_device_id id_table_combined[] = {
77 	{ USB_DEVICE(VENDOR_ID_DELORME, PRODUCT_ID_EARTHMATEUSB) },
78 	{ USB_DEVICE(VENDOR_ID_DELORME, PRODUCT_ID_EARTHMATEUSB_LT20) },
79 	{ USB_DEVICE(VENDOR_ID_CYPRESS, PRODUCT_ID_CYPHIDCOM) },
80 	{ USB_DEVICE(VENDOR_ID_POWERCOM, PRODUCT_ID_UPS) },
81 	{ USB_DEVICE(VENDOR_ID_FRWD, PRODUCT_ID_CYPHIDCOM_FRWD) },
82 	{ USB_DEVICE(VENDOR_ID_DAZZLE, PRODUCT_ID_CA42) },
83 	{ }						/* Terminating entry */
84 };
85 
86 MODULE_DEVICE_TABLE(usb, id_table_combined);
87 
88 enum packet_format {
89 	packet_format_1,  /* b0:status, b1:payload count */
90 	packet_format_2   /* b0[7:3]:status, b0[2:0]:payload count */
91 };
92 
93 struct cypress_private {
94 	spinlock_t lock;		   /* private lock */
95 	int chiptype;			   /* identifier of device, for quirks/etc */
96 	int bytes_in;			   /* used for statistics */
97 	int bytes_out;			   /* used for statistics */
98 	int cmd_count;			   /* used for statistics */
99 	int cmd_ctrl;			   /* always set this to 1 before issuing a command */
100 	struct kfifo write_fifo;	   /* write fifo */
101 	int write_urb_in_use;		   /* write urb in use indicator */
102 	int write_urb_interval;            /* interval to use for write urb */
103 	int read_urb_interval;             /* interval to use for read urb */
104 	int comm_is_ok;                    /* true if communication is (still) ok */
105 	int termios_initialized;
106 	__u8 line_control;	   	   /* holds dtr / rts value */
107 	__u8 current_status;	   	   /* received from last read - info on dsr,cts,cd,ri,etc */
108 	__u8 current_config;	   	   /* stores the current configuration byte */
109 	__u8 rx_flags;			   /* throttling - used from whiteheat/ftdi_sio */
110 	enum packet_format pkt_fmt;	   /* format to use for packet send / receive */
111 	int get_cfg_unsafe;		   /* If true, the CYPRESS_GET_CONFIG is unsafe */
112 	int baud_rate;			   /* stores current baud rate in
113 					      integer form */
114 	int isthrottled;		   /* if throttled, discard reads */
115 	char prev_status;		   /* used for TIOCMIWAIT */
116 	/* we pass a pointer to this as the argument sent to
117 	   cypress_set_termios old_termios */
118 	struct ktermios tmp_termios; 	   /* stores the old termios settings */
119 };
120 
121 /* function prototypes for the Cypress USB to serial device */
122 static int  cypress_earthmate_port_probe(struct usb_serial_port *port);
123 static int  cypress_hidcom_port_probe(struct usb_serial_port *port);
124 static int  cypress_ca42v2_port_probe(struct usb_serial_port *port);
125 static int  cypress_port_remove(struct usb_serial_port *port);
126 static int  cypress_open(struct tty_struct *tty, struct usb_serial_port *port);
127 static void cypress_close(struct usb_serial_port *port);
128 static void cypress_dtr_rts(struct usb_serial_port *port, int on);
129 static int  cypress_write(struct tty_struct *tty, struct usb_serial_port *port,
130 			const unsigned char *buf, int count);
131 static void cypress_send(struct usb_serial_port *port);
132 static int  cypress_write_room(struct tty_struct *tty);
133 static void cypress_set_termios(struct tty_struct *tty,
134 			struct usb_serial_port *port, struct ktermios *old);
135 static int  cypress_tiocmget(struct tty_struct *tty);
136 static int  cypress_tiocmset(struct tty_struct *tty,
137 			unsigned int set, unsigned int clear);
138 static int  cypress_chars_in_buffer(struct tty_struct *tty);
139 static void cypress_throttle(struct tty_struct *tty);
140 static void cypress_unthrottle(struct tty_struct *tty);
141 static void cypress_set_dead(struct usb_serial_port *port);
142 static void cypress_read_int_callback(struct urb *urb);
143 static void cypress_write_int_callback(struct urb *urb);
144 
145 static struct usb_serial_driver cypress_earthmate_device = {
146 	.driver = {
147 		.owner =		THIS_MODULE,
148 		.name =			"earthmate",
149 	},
150 	.description =			"DeLorme Earthmate USB",
151 	.id_table =			id_table_earthmate,
152 	.num_ports =			1,
153 	.port_probe =			cypress_earthmate_port_probe,
154 	.port_remove =			cypress_port_remove,
155 	.open =				cypress_open,
156 	.close =			cypress_close,
157 	.dtr_rts =			cypress_dtr_rts,
158 	.write =			cypress_write,
159 	.write_room =			cypress_write_room,
160 	.set_termios =			cypress_set_termios,
161 	.tiocmget =			cypress_tiocmget,
162 	.tiocmset =			cypress_tiocmset,
163 	.tiocmiwait =			usb_serial_generic_tiocmiwait,
164 	.chars_in_buffer =		cypress_chars_in_buffer,
165 	.throttle =		 	cypress_throttle,
166 	.unthrottle =			cypress_unthrottle,
167 	.read_int_callback =		cypress_read_int_callback,
168 	.write_int_callback =		cypress_write_int_callback,
169 };
170 
171 static struct usb_serial_driver cypress_hidcom_device = {
172 	.driver = {
173 		.owner =		THIS_MODULE,
174 		.name =			"cyphidcom",
175 	},
176 	.description =			"HID->COM RS232 Adapter",
177 	.id_table =			id_table_cyphidcomrs232,
178 	.num_ports =			1,
179 	.port_probe =			cypress_hidcom_port_probe,
180 	.port_remove =			cypress_port_remove,
181 	.open =				cypress_open,
182 	.close =			cypress_close,
183 	.dtr_rts =			cypress_dtr_rts,
184 	.write =			cypress_write,
185 	.write_room =			cypress_write_room,
186 	.set_termios =			cypress_set_termios,
187 	.tiocmget =			cypress_tiocmget,
188 	.tiocmset =			cypress_tiocmset,
189 	.tiocmiwait =			usb_serial_generic_tiocmiwait,
190 	.chars_in_buffer =		cypress_chars_in_buffer,
191 	.throttle =			cypress_throttle,
192 	.unthrottle =			cypress_unthrottle,
193 	.read_int_callback =		cypress_read_int_callback,
194 	.write_int_callback =		cypress_write_int_callback,
195 };
196 
197 static struct usb_serial_driver cypress_ca42v2_device = {
198 	.driver = {
199 		.owner =		THIS_MODULE,
200 		.name =			"nokiaca42v2",
201 	},
202 	.description =			"Nokia CA-42 V2 Adapter",
203 	.id_table =			id_table_nokiaca42v2,
204 	.num_ports =			1,
205 	.port_probe =			cypress_ca42v2_port_probe,
206 	.port_remove =			cypress_port_remove,
207 	.open =				cypress_open,
208 	.close =			cypress_close,
209 	.dtr_rts =			cypress_dtr_rts,
210 	.write =			cypress_write,
211 	.write_room =			cypress_write_room,
212 	.set_termios =			cypress_set_termios,
213 	.tiocmget =			cypress_tiocmget,
214 	.tiocmset =			cypress_tiocmset,
215 	.tiocmiwait =			usb_serial_generic_tiocmiwait,
216 	.chars_in_buffer =		cypress_chars_in_buffer,
217 	.throttle =			cypress_throttle,
218 	.unthrottle =			cypress_unthrottle,
219 	.read_int_callback =		cypress_read_int_callback,
220 	.write_int_callback =		cypress_write_int_callback,
221 };
222 
223 static struct usb_serial_driver * const serial_drivers[] = {
224 	&cypress_earthmate_device, &cypress_hidcom_device,
225 	&cypress_ca42v2_device, NULL
226 };
227 
228 /*****************************************************************************
229  * Cypress serial helper functions
230  *****************************************************************************/
231 
232 /* FRWD Dongle hidcom needs to skip reset and speed checks */
233 static inline bool is_frwd(struct usb_device *dev)
234 {
235 	return ((le16_to_cpu(dev->descriptor.idVendor) == VENDOR_ID_FRWD) &&
236 		(le16_to_cpu(dev->descriptor.idProduct) == PRODUCT_ID_CYPHIDCOM_FRWD));
237 }
238 
239 static int analyze_baud_rate(struct usb_serial_port *port, speed_t new_rate)
240 {
241 	struct cypress_private *priv;
242 	priv = usb_get_serial_port_data(port);
243 
244 	if (unstable_bauds)
245 		return new_rate;
246 
247 	/* FRWD Dongle uses 115200 bps */
248 	if (is_frwd(port->serial->dev))
249 		return new_rate;
250 
251 	/*
252 	 * The general purpose firmware for the Cypress M8 allows for
253 	 * a maximum speed of 57600bps (I have no idea whether DeLorme
254 	 * chose to use the general purpose firmware or not), if you
255 	 * need to modify this speed setting for your own project
256 	 * please add your own chiptype and modify the code likewise.
257 	 * The Cypress HID->COM device will work successfully up to
258 	 * 115200bps (but the actual throughput is around 3kBps).
259 	 */
260 	if (port->serial->dev->speed == USB_SPEED_LOW) {
261 		/*
262 		 * Mike Isely <isely@pobox.com> 2-Feb-2008: The
263 		 * Cypress app note that describes this mechanism
264 		 * states the the low-speed part can't handle more
265 		 * than 800 bytes/sec, in which case 4800 baud is the
266 		 * safest speed for a part like that.
267 		 */
268 		if (new_rate > 4800) {
269 			dev_dbg(&port->dev,
270 				"%s - failed setting baud rate, device incapable speed %d\n",
271 				__func__, new_rate);
272 			return -1;
273 		}
274 	}
275 	switch (priv->chiptype) {
276 	case CT_EARTHMATE:
277 		if (new_rate <= 600) {
278 			/* 300 and 600 baud rates are supported under
279 			 * the generic firmware, but are not used with
280 			 * NMEA and SiRF protocols */
281 			dev_dbg(&port->dev,
282 				"%s - failed setting baud rate, unsupported speed of %d on Earthmate GPS\n",
283 				__func__, new_rate);
284 			return -1;
285 		}
286 		break;
287 	default:
288 		break;
289 	}
290 	return new_rate;
291 }
292 
293 
294 /* This function can either set or retrieve the current serial line settings */
295 static int cypress_serial_control(struct tty_struct *tty,
296 	struct usb_serial_port *port, speed_t baud_rate, int data_bits,
297 	int stop_bits, int parity_enable, int parity_type, int reset,
298 	int cypress_request_type)
299 {
300 	int new_baudrate = 0, retval = 0, tries = 0;
301 	struct cypress_private *priv;
302 	struct device *dev = &port->dev;
303 	u8 *feature_buffer;
304 	const unsigned int feature_len = 5;
305 	unsigned long flags;
306 
307 	priv = usb_get_serial_port_data(port);
308 
309 	if (!priv->comm_is_ok)
310 		return -ENODEV;
311 
312 	feature_buffer = kcalloc(feature_len, sizeof(u8), GFP_KERNEL);
313 	if (!feature_buffer)
314 		return -ENOMEM;
315 
316 	switch (cypress_request_type) {
317 	case CYPRESS_SET_CONFIG:
318 		/* 0 means 'Hang up' so doesn't change the true bit rate */
319 		new_baudrate = priv->baud_rate;
320 		if (baud_rate && baud_rate != priv->baud_rate) {
321 			dev_dbg(dev, "%s - baud rate is changing\n", __func__);
322 			retval = analyze_baud_rate(port, baud_rate);
323 			if (retval >= 0) {
324 				new_baudrate = retval;
325 				dev_dbg(dev, "%s - New baud rate set to %d\n",
326 					__func__, new_baudrate);
327 			}
328 		}
329 		dev_dbg(dev, "%s - baud rate is being sent as %d\n", __func__,
330 			new_baudrate);
331 
332 		/* fill the feature_buffer with new configuration */
333 		put_unaligned_le32(new_baudrate, feature_buffer);
334 		feature_buffer[4] |= data_bits;   /* assign data bits in 2 bit space ( max 3 ) */
335 		/* 1 bit gap */
336 		feature_buffer[4] |= (stop_bits << 3);   /* assign stop bits in 1 bit space */
337 		feature_buffer[4] |= (parity_enable << 4);   /* assign parity flag in 1 bit space */
338 		feature_buffer[4] |= (parity_type << 5);   /* assign parity type in 1 bit space */
339 		/* 1 bit gap */
340 		feature_buffer[4] |= (reset << 7);   /* assign reset at end of byte, 1 bit space */
341 
342 		dev_dbg(dev, "%s - device is being sent this feature report:\n", __func__);
343 		dev_dbg(dev, "%s - %02X - %02X - %02X - %02X - %02X\n", __func__,
344 			feature_buffer[0], feature_buffer[1],
345 			feature_buffer[2], feature_buffer[3],
346 			feature_buffer[4]);
347 
348 		do {
349 			retval = usb_control_msg(port->serial->dev,
350 					usb_sndctrlpipe(port->serial->dev, 0),
351 					HID_REQ_SET_REPORT,
352 					USB_DIR_OUT | USB_RECIP_INTERFACE | USB_TYPE_CLASS,
353 					0x0300, 0, feature_buffer,
354 					feature_len, 500);
355 
356 			if (tries++ >= 3)
357 				break;
358 
359 		} while (retval != feature_len &&
360 			 retval != -ENODEV);
361 
362 		if (retval != feature_len) {
363 			dev_err(dev, "%s - failed sending serial line settings - %d\n",
364 				__func__, retval);
365 			cypress_set_dead(port);
366 		} else {
367 			spin_lock_irqsave(&priv->lock, flags);
368 			priv->baud_rate = new_baudrate;
369 			priv->current_config = feature_buffer[4];
370 			spin_unlock_irqrestore(&priv->lock, flags);
371 			/* If we asked for a speed change encode it */
372 			if (baud_rate)
373 				tty_encode_baud_rate(tty,
374 					new_baudrate, new_baudrate);
375 		}
376 	break;
377 	case CYPRESS_GET_CONFIG:
378 		if (priv->get_cfg_unsafe) {
379 			/* Not implemented for this device,
380 			   and if we try to do it we're likely
381 			   to crash the hardware. */
382 			retval = -ENOTTY;
383 			goto out;
384 		}
385 		dev_dbg(dev, "%s - retreiving serial line settings\n", __func__);
386 		do {
387 			retval = usb_control_msg(port->serial->dev,
388 					usb_rcvctrlpipe(port->serial->dev, 0),
389 					HID_REQ_GET_REPORT,
390 					USB_DIR_IN | USB_RECIP_INTERFACE | USB_TYPE_CLASS,
391 					0x0300, 0, feature_buffer,
392 					feature_len, 500);
393 
394 			if (tries++ >= 3)
395 				break;
396 		} while (retval != feature_len
397 						&& retval != -ENODEV);
398 
399 		if (retval != feature_len) {
400 			dev_err(dev, "%s - failed to retrieve serial line settings - %d\n",
401 				__func__, retval);
402 			cypress_set_dead(port);
403 			goto out;
404 		} else {
405 			spin_lock_irqsave(&priv->lock, flags);
406 			/* store the config in one byte, and later
407 			   use bit masks to check values */
408 			priv->current_config = feature_buffer[4];
409 			priv->baud_rate = get_unaligned_le32(feature_buffer);
410 			spin_unlock_irqrestore(&priv->lock, flags);
411 		}
412 	}
413 	spin_lock_irqsave(&priv->lock, flags);
414 	++priv->cmd_count;
415 	spin_unlock_irqrestore(&priv->lock, flags);
416 out:
417 	kfree(feature_buffer);
418 	return retval;
419 } /* cypress_serial_control */
420 
421 
422 static void cypress_set_dead(struct usb_serial_port *port)
423 {
424 	struct cypress_private *priv = usb_get_serial_port_data(port);
425 	unsigned long flags;
426 
427 	spin_lock_irqsave(&priv->lock, flags);
428 	if (!priv->comm_is_ok) {
429 		spin_unlock_irqrestore(&priv->lock, flags);
430 		return;
431 	}
432 	priv->comm_is_ok = 0;
433 	spin_unlock_irqrestore(&priv->lock, flags);
434 
435 	dev_err(&port->dev, "cypress_m8 suspending failing port %d - "
436 		"interval might be too short\n", port->port_number);
437 }
438 
439 
440 /*****************************************************************************
441  * Cypress serial driver functions
442  *****************************************************************************/
443 
444 
445 static int cypress_generic_port_probe(struct usb_serial_port *port)
446 {
447 	struct usb_serial *serial = port->serial;
448 	struct cypress_private *priv;
449 
450 	if (!port->interrupt_out_urb || !port->interrupt_in_urb) {
451 		dev_err(&port->dev, "required endpoint is missing\n");
452 		return -ENODEV;
453 	}
454 
455 	priv = kzalloc(sizeof(struct cypress_private), GFP_KERNEL);
456 	if (!priv)
457 		return -ENOMEM;
458 
459 	priv->comm_is_ok = !0;
460 	spin_lock_init(&priv->lock);
461 	if (kfifo_alloc(&priv->write_fifo, CYPRESS_BUF_SIZE, GFP_KERNEL)) {
462 		kfree(priv);
463 		return -ENOMEM;
464 	}
465 
466 	/* Skip reset for FRWD device. It is a workaound:
467 	   device hangs if it receives SET_CONFIGURE in Configured
468 	   state. */
469 	if (!is_frwd(serial->dev))
470 		usb_reset_configuration(serial->dev);
471 
472 	priv->cmd_ctrl = 0;
473 	priv->line_control = 0;
474 	priv->termios_initialized = 0;
475 	priv->rx_flags = 0;
476 	/* Default packet format setting is determined by packet size.
477 	   Anything with a size larger then 9 must have a separate
478 	   count field since the 3 bit count field is otherwise too
479 	   small.  Otherwise we can use the slightly more compact
480 	   format.  This is in accordance with the cypress_m8 serial
481 	   converter app note. */
482 	if (port->interrupt_out_size > 9)
483 		priv->pkt_fmt = packet_format_1;
484 	else
485 		priv->pkt_fmt = packet_format_2;
486 
487 	if (interval > 0) {
488 		priv->write_urb_interval = interval;
489 		priv->read_urb_interval = interval;
490 		dev_dbg(&port->dev, "%s - read & write intervals forced to %d\n",
491 			__func__, interval);
492 	} else {
493 		priv->write_urb_interval = port->interrupt_out_urb->interval;
494 		priv->read_urb_interval = port->interrupt_in_urb->interval;
495 		dev_dbg(&port->dev, "%s - intervals: read=%d write=%d\n",
496 			__func__, priv->read_urb_interval,
497 			priv->write_urb_interval);
498 	}
499 	usb_set_serial_port_data(port, priv);
500 
501 	port->port.drain_delay = 256;
502 
503 	return 0;
504 }
505 
506 
507 static int cypress_earthmate_port_probe(struct usb_serial_port *port)
508 {
509 	struct usb_serial *serial = port->serial;
510 	struct cypress_private *priv;
511 	int ret;
512 
513 	ret = cypress_generic_port_probe(port);
514 	if (ret) {
515 		dev_dbg(&port->dev, "%s - Failed setting up port\n", __func__);
516 		return ret;
517 	}
518 
519 	priv = usb_get_serial_port_data(port);
520 	priv->chiptype = CT_EARTHMATE;
521 	/* All Earthmate devices use the separated-count packet
522 	   format!  Idiotic. */
523 	priv->pkt_fmt = packet_format_1;
524 	if (serial->dev->descriptor.idProduct !=
525 				cpu_to_le16(PRODUCT_ID_EARTHMATEUSB)) {
526 		/* The old original USB Earthmate seemed able to
527 		   handle GET_CONFIG requests; everything they've
528 		   produced since that time crashes if this command is
529 		   attempted :-( */
530 		dev_dbg(&port->dev,
531 			"%s - Marking this device as unsafe for GET_CONFIG commands\n",
532 			__func__);
533 		priv->get_cfg_unsafe = !0;
534 	}
535 
536 	return 0;
537 }
538 
539 static int cypress_hidcom_port_probe(struct usb_serial_port *port)
540 {
541 	struct cypress_private *priv;
542 	int ret;
543 
544 	ret = cypress_generic_port_probe(port);
545 	if (ret) {
546 		dev_dbg(&port->dev, "%s - Failed setting up port\n", __func__);
547 		return ret;
548 	}
549 
550 	priv = usb_get_serial_port_data(port);
551 	priv->chiptype = CT_CYPHIDCOM;
552 
553 	return 0;
554 }
555 
556 static int cypress_ca42v2_port_probe(struct usb_serial_port *port)
557 {
558 	struct cypress_private *priv;
559 	int ret;
560 
561 	ret = cypress_generic_port_probe(port);
562 	if (ret) {
563 		dev_dbg(&port->dev, "%s - Failed setting up port\n", __func__);
564 		return ret;
565 	}
566 
567 	priv = usb_get_serial_port_data(port);
568 	priv->chiptype = CT_CA42V2;
569 
570 	return 0;
571 }
572 
573 static int cypress_port_remove(struct usb_serial_port *port)
574 {
575 	struct cypress_private *priv;
576 
577 	priv = usb_get_serial_port_data(port);
578 
579 	kfifo_free(&priv->write_fifo);
580 	kfree(priv);
581 
582 	return 0;
583 }
584 
585 static int cypress_open(struct tty_struct *tty, struct usb_serial_port *port)
586 {
587 	struct cypress_private *priv = usb_get_serial_port_data(port);
588 	struct usb_serial *serial = port->serial;
589 	unsigned long flags;
590 	int result = 0;
591 
592 	if (!priv->comm_is_ok)
593 		return -EIO;
594 
595 	/* clear halts before open */
596 	usb_clear_halt(serial->dev, 0x81);
597 	usb_clear_halt(serial->dev, 0x02);
598 
599 	spin_lock_irqsave(&priv->lock, flags);
600 	/* reset read/write statistics */
601 	priv->bytes_in = 0;
602 	priv->bytes_out = 0;
603 	priv->cmd_count = 0;
604 	priv->rx_flags = 0;
605 	spin_unlock_irqrestore(&priv->lock, flags);
606 
607 	/* Set termios */
608 	cypress_send(port);
609 
610 	if (tty)
611 		cypress_set_termios(tty, port, &priv->tmp_termios);
612 
613 	/* setup the port and start reading from the device */
614 	usb_fill_int_urb(port->interrupt_in_urb, serial->dev,
615 		usb_rcvintpipe(serial->dev, port->interrupt_in_endpointAddress),
616 		port->interrupt_in_urb->transfer_buffer,
617 		port->interrupt_in_urb->transfer_buffer_length,
618 		cypress_read_int_callback, port, priv->read_urb_interval);
619 	result = usb_submit_urb(port->interrupt_in_urb, GFP_KERNEL);
620 
621 	if (result) {
622 		dev_err(&port->dev,
623 			"%s - failed submitting read urb, error %d\n",
624 							__func__, result);
625 		cypress_set_dead(port);
626 	}
627 
628 	return result;
629 } /* cypress_open */
630 
631 static void cypress_dtr_rts(struct usb_serial_port *port, int on)
632 {
633 	struct cypress_private *priv = usb_get_serial_port_data(port);
634 	/* drop dtr and rts */
635 	spin_lock_irq(&priv->lock);
636 	if (on == 0)
637 		priv->line_control = 0;
638 	else
639 		priv->line_control = CONTROL_DTR | CONTROL_RTS;
640 	priv->cmd_ctrl = 1;
641 	spin_unlock_irq(&priv->lock);
642 	cypress_write(NULL, port, NULL, 0);
643 }
644 
645 static void cypress_close(struct usb_serial_port *port)
646 {
647 	struct cypress_private *priv = usb_get_serial_port_data(port);
648 	unsigned long flags;
649 
650 	spin_lock_irqsave(&priv->lock, flags);
651 	kfifo_reset_out(&priv->write_fifo);
652 	spin_unlock_irqrestore(&priv->lock, flags);
653 
654 	dev_dbg(&port->dev, "%s - stopping urbs\n", __func__);
655 	usb_kill_urb(port->interrupt_in_urb);
656 	usb_kill_urb(port->interrupt_out_urb);
657 
658 	if (stats)
659 		dev_info(&port->dev, "Statistics: %d Bytes In | %d Bytes Out | %d Commands Issued\n",
660 			priv->bytes_in, priv->bytes_out, priv->cmd_count);
661 } /* cypress_close */
662 
663 
664 static int cypress_write(struct tty_struct *tty, struct usb_serial_port *port,
665 					const unsigned char *buf, int count)
666 {
667 	struct cypress_private *priv = usb_get_serial_port_data(port);
668 
669 	dev_dbg(&port->dev, "%s - %d bytes\n", __func__, count);
670 
671 	/* line control commands, which need to be executed immediately,
672 	   are not put into the buffer for obvious reasons.
673 	 */
674 	if (priv->cmd_ctrl) {
675 		count = 0;
676 		goto finish;
677 	}
678 
679 	if (!count)
680 		return count;
681 
682 	count = kfifo_in_locked(&priv->write_fifo, buf, count, &priv->lock);
683 
684 finish:
685 	cypress_send(port);
686 
687 	return count;
688 } /* cypress_write */
689 
690 
691 static void cypress_send(struct usb_serial_port *port)
692 {
693 	int count = 0, result, offset, actual_size;
694 	struct cypress_private *priv = usb_get_serial_port_data(port);
695 	struct device *dev = &port->dev;
696 	unsigned long flags;
697 
698 	if (!priv->comm_is_ok)
699 		return;
700 
701 	dev_dbg(dev, "%s - interrupt out size is %d\n", __func__,
702 		port->interrupt_out_size);
703 
704 	spin_lock_irqsave(&priv->lock, flags);
705 	if (priv->write_urb_in_use) {
706 		dev_dbg(dev, "%s - can't write, urb in use\n", __func__);
707 		spin_unlock_irqrestore(&priv->lock, flags);
708 		return;
709 	}
710 	spin_unlock_irqrestore(&priv->lock, flags);
711 
712 	/* clear buffer */
713 	memset(port->interrupt_out_urb->transfer_buffer, 0,
714 						port->interrupt_out_size);
715 
716 	spin_lock_irqsave(&priv->lock, flags);
717 	switch (priv->pkt_fmt) {
718 	default:
719 	case packet_format_1:
720 		/* this is for the CY7C64013... */
721 		offset = 2;
722 		port->interrupt_out_buffer[0] = priv->line_control;
723 		break;
724 	case packet_format_2:
725 		/* this is for the CY7C63743... */
726 		offset = 1;
727 		port->interrupt_out_buffer[0] = priv->line_control;
728 		break;
729 	}
730 
731 	if (priv->line_control & CONTROL_RESET)
732 		priv->line_control &= ~CONTROL_RESET;
733 
734 	if (priv->cmd_ctrl) {
735 		priv->cmd_count++;
736 		dev_dbg(dev, "%s - line control command being issued\n", __func__);
737 		spin_unlock_irqrestore(&priv->lock, flags);
738 		goto send;
739 	} else
740 		spin_unlock_irqrestore(&priv->lock, flags);
741 
742 	count = kfifo_out_locked(&priv->write_fifo,
743 					&port->interrupt_out_buffer[offset],
744 					port->interrupt_out_size - offset,
745 					&priv->lock);
746 	if (count == 0)
747 		return;
748 
749 	switch (priv->pkt_fmt) {
750 	default:
751 	case packet_format_1:
752 		port->interrupt_out_buffer[1] = count;
753 		break;
754 	case packet_format_2:
755 		port->interrupt_out_buffer[0] |= count;
756 	}
757 
758 	dev_dbg(dev, "%s - count is %d\n", __func__, count);
759 
760 send:
761 	spin_lock_irqsave(&priv->lock, flags);
762 	priv->write_urb_in_use = 1;
763 	spin_unlock_irqrestore(&priv->lock, flags);
764 
765 	if (priv->cmd_ctrl)
766 		actual_size = 1;
767 	else
768 		actual_size = count +
769 			      (priv->pkt_fmt == packet_format_1 ? 2 : 1);
770 
771 	usb_serial_debug_data(dev, __func__, port->interrupt_out_size,
772 			      port->interrupt_out_urb->transfer_buffer);
773 
774 	usb_fill_int_urb(port->interrupt_out_urb, port->serial->dev,
775 		usb_sndintpipe(port->serial->dev, port->interrupt_out_endpointAddress),
776 		port->interrupt_out_buffer, port->interrupt_out_size,
777 		cypress_write_int_callback, port, priv->write_urb_interval);
778 	result = usb_submit_urb(port->interrupt_out_urb, GFP_ATOMIC);
779 	if (result) {
780 		dev_err_console(port,
781 				"%s - failed submitting write urb, error %d\n",
782 							__func__, result);
783 		priv->write_urb_in_use = 0;
784 		cypress_set_dead(port);
785 	}
786 
787 	spin_lock_irqsave(&priv->lock, flags);
788 	if (priv->cmd_ctrl)
789 		priv->cmd_ctrl = 0;
790 
791 	/* do not count the line control and size bytes */
792 	priv->bytes_out += count;
793 	spin_unlock_irqrestore(&priv->lock, flags);
794 
795 	usb_serial_port_softint(port);
796 } /* cypress_send */
797 
798 
799 /* returns how much space is available in the soft buffer */
800 static int cypress_write_room(struct tty_struct *tty)
801 {
802 	struct usb_serial_port *port = tty->driver_data;
803 	struct cypress_private *priv = usb_get_serial_port_data(port);
804 	int room = 0;
805 	unsigned long flags;
806 
807 	spin_lock_irqsave(&priv->lock, flags);
808 	room = kfifo_avail(&priv->write_fifo);
809 	spin_unlock_irqrestore(&priv->lock, flags);
810 
811 	dev_dbg(&port->dev, "%s - returns %d\n", __func__, room);
812 	return room;
813 }
814 
815 
816 static int cypress_tiocmget(struct tty_struct *tty)
817 {
818 	struct usb_serial_port *port = tty->driver_data;
819 	struct cypress_private *priv = usb_get_serial_port_data(port);
820 	__u8 status, control;
821 	unsigned int result = 0;
822 	unsigned long flags;
823 
824 	spin_lock_irqsave(&priv->lock, flags);
825 	control = priv->line_control;
826 	status = priv->current_status;
827 	spin_unlock_irqrestore(&priv->lock, flags);
828 
829 	result = ((control & CONTROL_DTR)        ? TIOCM_DTR : 0)
830 		| ((control & CONTROL_RTS)       ? TIOCM_RTS : 0)
831 		| ((status & UART_CTS)        ? TIOCM_CTS : 0)
832 		| ((status & UART_DSR)        ? TIOCM_DSR : 0)
833 		| ((status & UART_RI)         ? TIOCM_RI  : 0)
834 		| ((status & UART_CD)         ? TIOCM_CD  : 0);
835 
836 	dev_dbg(&port->dev, "%s - result = %x\n", __func__, result);
837 
838 	return result;
839 }
840 
841 
842 static int cypress_tiocmset(struct tty_struct *tty,
843 			       unsigned int set, unsigned int clear)
844 {
845 	struct usb_serial_port *port = tty->driver_data;
846 	struct cypress_private *priv = usb_get_serial_port_data(port);
847 	unsigned long flags;
848 
849 	spin_lock_irqsave(&priv->lock, flags);
850 	if (set & TIOCM_RTS)
851 		priv->line_control |= CONTROL_RTS;
852 	if (set & TIOCM_DTR)
853 		priv->line_control |= CONTROL_DTR;
854 	if (clear & TIOCM_RTS)
855 		priv->line_control &= ~CONTROL_RTS;
856 	if (clear & TIOCM_DTR)
857 		priv->line_control &= ~CONTROL_DTR;
858 	priv->cmd_ctrl = 1;
859 	spin_unlock_irqrestore(&priv->lock, flags);
860 
861 	return cypress_write(tty, port, NULL, 0);
862 }
863 
864 static void cypress_set_termios(struct tty_struct *tty,
865 	struct usb_serial_port *port, struct ktermios *old_termios)
866 {
867 	struct cypress_private *priv = usb_get_serial_port_data(port);
868 	struct device *dev = &port->dev;
869 	int data_bits, stop_bits, parity_type, parity_enable;
870 	unsigned cflag, iflag;
871 	unsigned long flags;
872 	__u8 oldlines;
873 	int linechange = 0;
874 
875 	spin_lock_irqsave(&priv->lock, flags);
876 	/* We can't clean this one up as we don't know the device type
877 	   early enough */
878 	if (!priv->termios_initialized) {
879 		if (priv->chiptype == CT_EARTHMATE) {
880 			tty->termios = tty_std_termios;
881 			tty->termios.c_cflag = B4800 | CS8 | CREAD | HUPCL |
882 				CLOCAL;
883 			tty->termios.c_ispeed = 4800;
884 			tty->termios.c_ospeed = 4800;
885 		} else if (priv->chiptype == CT_CYPHIDCOM) {
886 			tty->termios = tty_std_termios;
887 			tty->termios.c_cflag = B9600 | CS8 | CREAD | HUPCL |
888 				CLOCAL;
889 			tty->termios.c_ispeed = 9600;
890 			tty->termios.c_ospeed = 9600;
891 		} else if (priv->chiptype == CT_CA42V2) {
892 			tty->termios = tty_std_termios;
893 			tty->termios.c_cflag = B9600 | CS8 | CREAD | HUPCL |
894 				CLOCAL;
895 			tty->termios.c_ispeed = 9600;
896 			tty->termios.c_ospeed = 9600;
897 		}
898 		priv->termios_initialized = 1;
899 	}
900 	spin_unlock_irqrestore(&priv->lock, flags);
901 
902 	/* Unsupported features need clearing */
903 	tty->termios.c_cflag &= ~(CMSPAR|CRTSCTS);
904 
905 	cflag = tty->termios.c_cflag;
906 	iflag = tty->termios.c_iflag;
907 
908 	/* check if there are new settings */
909 	if (old_termios) {
910 		spin_lock_irqsave(&priv->lock, flags);
911 		priv->tmp_termios = tty->termios;
912 		spin_unlock_irqrestore(&priv->lock, flags);
913 	}
914 
915 	/* set number of data bits, parity, stop bits */
916 	/* when parity is disabled the parity type bit is ignored */
917 
918 	/* 1 means 2 stop bits, 0 means 1 stop bit */
919 	stop_bits = cflag & CSTOPB ? 1 : 0;
920 
921 	if (cflag & PARENB) {
922 		parity_enable = 1;
923 		/* 1 means odd parity, 0 means even parity */
924 		parity_type = cflag & PARODD ? 1 : 0;
925 	} else
926 		parity_enable = parity_type = 0;
927 
928 	switch (cflag & CSIZE) {
929 	case CS5:
930 		data_bits = 0;
931 		break;
932 	case CS6:
933 		data_bits = 1;
934 		break;
935 	case CS7:
936 		data_bits = 2;
937 		break;
938 	case CS8:
939 		data_bits = 3;
940 		break;
941 	default:
942 		dev_err(dev, "%s - CSIZE was set, but not CS5-CS8\n", __func__);
943 		data_bits = 3;
944 	}
945 	spin_lock_irqsave(&priv->lock, flags);
946 	oldlines = priv->line_control;
947 	if ((cflag & CBAUD) == B0) {
948 		/* drop dtr and rts */
949 		dev_dbg(dev, "%s - dropping the lines, baud rate 0bps\n", __func__);
950 		priv->line_control &= ~(CONTROL_DTR | CONTROL_RTS);
951 	} else
952 		priv->line_control = (CONTROL_DTR | CONTROL_RTS);
953 	spin_unlock_irqrestore(&priv->lock, flags);
954 
955 	dev_dbg(dev, "%s - sending %d stop_bits, %d parity_enable, %d parity_type, %d data_bits (+5)\n",
956 		__func__, stop_bits, parity_enable, parity_type, data_bits);
957 
958 	cypress_serial_control(tty, port, tty_get_baud_rate(tty),
959 			data_bits, stop_bits,
960 			parity_enable, parity_type,
961 			0, CYPRESS_SET_CONFIG);
962 
963 	/* we perform a CYPRESS_GET_CONFIG so that the current settings are
964 	 * filled into the private structure this should confirm that all is
965 	 * working if it returns what we just set */
966 	cypress_serial_control(tty, port, 0, 0, 0, 0, 0, 0, CYPRESS_GET_CONFIG);
967 
968 	/* Here we can define custom tty settings for devices; the main tty
969 	 * termios flag base comes from empeg.c */
970 
971 	spin_lock_irqsave(&priv->lock, flags);
972 	if (priv->chiptype == CT_EARTHMATE && priv->baud_rate == 4800) {
973 		dev_dbg(dev, "Using custom termios settings for a baud rate of 4800bps.\n");
974 		/* define custom termios settings for NMEA protocol */
975 
976 		tty->termios.c_iflag /* input modes - */
977 			&= ~(IGNBRK  /* disable ignore break */
978 			| BRKINT     /* disable break causes interrupt */
979 			| PARMRK     /* disable mark parity errors */
980 			| ISTRIP     /* disable clear high bit of input char */
981 			| INLCR      /* disable translate NL to CR */
982 			| IGNCR      /* disable ignore CR */
983 			| ICRNL      /* disable translate CR to NL */
984 			| IXON);     /* disable enable XON/XOFF flow control */
985 
986 		tty->termios.c_oflag /* output modes */
987 			&= ~OPOST;    /* disable postprocess output char */
988 
989 		tty->termios.c_lflag /* line discipline modes */
990 			&= ~(ECHO     /* disable echo input characters */
991 			| ECHONL      /* disable echo new line */
992 			| ICANON      /* disable erase, kill, werase, and rprnt
993 					 special characters */
994 			| ISIG        /* disable interrupt, quit, and suspend
995 					 special characters */
996 			| IEXTEN);    /* disable non-POSIX special characters */
997 	} /* CT_CYPHIDCOM: Application should handle this for device */
998 
999 	linechange = (priv->line_control != oldlines);
1000 	spin_unlock_irqrestore(&priv->lock, flags);
1001 
1002 	/* if necessary, set lines */
1003 	if (linechange) {
1004 		priv->cmd_ctrl = 1;
1005 		cypress_write(tty, port, NULL, 0);
1006 	}
1007 } /* cypress_set_termios */
1008 
1009 
1010 /* returns amount of data still left in soft buffer */
1011 static int cypress_chars_in_buffer(struct tty_struct *tty)
1012 {
1013 	struct usb_serial_port *port = tty->driver_data;
1014 	struct cypress_private *priv = usb_get_serial_port_data(port);
1015 	int chars = 0;
1016 	unsigned long flags;
1017 
1018 	spin_lock_irqsave(&priv->lock, flags);
1019 	chars = kfifo_len(&priv->write_fifo);
1020 	spin_unlock_irqrestore(&priv->lock, flags);
1021 
1022 	dev_dbg(&port->dev, "%s - returns %d\n", __func__, chars);
1023 	return chars;
1024 }
1025 
1026 
1027 static void cypress_throttle(struct tty_struct *tty)
1028 {
1029 	struct usb_serial_port *port = tty->driver_data;
1030 	struct cypress_private *priv = usb_get_serial_port_data(port);
1031 
1032 	spin_lock_irq(&priv->lock);
1033 	priv->rx_flags = THROTTLED;
1034 	spin_unlock_irq(&priv->lock);
1035 }
1036 
1037 
1038 static void cypress_unthrottle(struct tty_struct *tty)
1039 {
1040 	struct usb_serial_port *port = tty->driver_data;
1041 	struct cypress_private *priv = usb_get_serial_port_data(port);
1042 	int actually_throttled, result;
1043 
1044 	spin_lock_irq(&priv->lock);
1045 	actually_throttled = priv->rx_flags & ACTUALLY_THROTTLED;
1046 	priv->rx_flags = 0;
1047 	spin_unlock_irq(&priv->lock);
1048 
1049 	if (!priv->comm_is_ok)
1050 		return;
1051 
1052 	if (actually_throttled) {
1053 		result = usb_submit_urb(port->interrupt_in_urb, GFP_KERNEL);
1054 		if (result) {
1055 			dev_err(&port->dev, "%s - failed submitting read urb, "
1056 					"error %d\n", __func__, result);
1057 			cypress_set_dead(port);
1058 		}
1059 	}
1060 }
1061 
1062 
1063 static void cypress_read_int_callback(struct urb *urb)
1064 {
1065 	struct usb_serial_port *port = urb->context;
1066 	struct cypress_private *priv = usb_get_serial_port_data(port);
1067 	struct device *dev = &urb->dev->dev;
1068 	struct tty_struct *tty;
1069 	unsigned char *data = urb->transfer_buffer;
1070 	unsigned long flags;
1071 	char tty_flag = TTY_NORMAL;
1072 	int bytes = 0;
1073 	int result;
1074 	int i = 0;
1075 	int status = urb->status;
1076 
1077 	switch (status) {
1078 	case 0: /* success */
1079 		break;
1080 	case -ECONNRESET:
1081 	case -ENOENT:
1082 	case -ESHUTDOWN:
1083 		/* precursor to disconnect so just go away */
1084 		return;
1085 	case -EPIPE:
1086 		/* Can't call usb_clear_halt while in_interrupt */
1087 		/* FALLS THROUGH */
1088 	default:
1089 		/* something ugly is going on... */
1090 		dev_err(dev, "%s - unexpected nonzero read status received: %d\n",
1091 			__func__, status);
1092 		cypress_set_dead(port);
1093 		return;
1094 	}
1095 
1096 	spin_lock_irqsave(&priv->lock, flags);
1097 	if (priv->rx_flags & THROTTLED) {
1098 		dev_dbg(dev, "%s - now throttling\n", __func__);
1099 		priv->rx_flags |= ACTUALLY_THROTTLED;
1100 		spin_unlock_irqrestore(&priv->lock, flags);
1101 		return;
1102 	}
1103 	spin_unlock_irqrestore(&priv->lock, flags);
1104 
1105 	tty = tty_port_tty_get(&port->port);
1106 	if (!tty) {
1107 		dev_dbg(dev, "%s - bad tty pointer - exiting\n", __func__);
1108 		return;
1109 	}
1110 
1111 	spin_lock_irqsave(&priv->lock, flags);
1112 	result = urb->actual_length;
1113 	switch (priv->pkt_fmt) {
1114 	default:
1115 	case packet_format_1:
1116 		/* This is for the CY7C64013... */
1117 		priv->current_status = data[0] & 0xF8;
1118 		bytes = data[1] + 2;
1119 		i = 2;
1120 		break;
1121 	case packet_format_2:
1122 		/* This is for the CY7C63743... */
1123 		priv->current_status = data[0] & 0xF8;
1124 		bytes = (data[0] & 0x07) + 1;
1125 		i = 1;
1126 		break;
1127 	}
1128 	spin_unlock_irqrestore(&priv->lock, flags);
1129 	if (result < bytes) {
1130 		dev_dbg(dev,
1131 			"%s - wrong packet size - received %d bytes but packet said %d bytes\n",
1132 			__func__, result, bytes);
1133 		goto continue_read;
1134 	}
1135 
1136 	usb_serial_debug_data(&port->dev, __func__, urb->actual_length, data);
1137 
1138 	spin_lock_irqsave(&priv->lock, flags);
1139 	/* check to see if status has changed */
1140 	if (priv->current_status != priv->prev_status) {
1141 		u8 delta = priv->current_status ^ priv->prev_status;
1142 
1143 		if (delta & UART_MSR_MASK) {
1144 			if (delta & UART_CTS)
1145 				port->icount.cts++;
1146 			if (delta & UART_DSR)
1147 				port->icount.dsr++;
1148 			if (delta & UART_RI)
1149 				port->icount.rng++;
1150 			if (delta & UART_CD)
1151 				port->icount.dcd++;
1152 
1153 			wake_up_interruptible(&port->port.delta_msr_wait);
1154 		}
1155 
1156 		priv->prev_status = priv->current_status;
1157 	}
1158 	spin_unlock_irqrestore(&priv->lock, flags);
1159 
1160 	/* hangup, as defined in acm.c... this might be a bad place for it
1161 	 * though */
1162 	if (tty && !C_CLOCAL(tty) && !(priv->current_status & UART_CD)) {
1163 		dev_dbg(dev, "%s - calling hangup\n", __func__);
1164 		tty_hangup(tty);
1165 		goto continue_read;
1166 	}
1167 
1168 	/* There is one error bit... I'm assuming it is a parity error
1169 	 * indicator as the generic firmware will set this bit to 1 if a
1170 	 * parity error occurs.
1171 	 * I can not find reference to any other error events. */
1172 	spin_lock_irqsave(&priv->lock, flags);
1173 	if (priv->current_status & CYP_ERROR) {
1174 		spin_unlock_irqrestore(&priv->lock, flags);
1175 		tty_flag = TTY_PARITY;
1176 		dev_dbg(dev, "%s - Parity Error detected\n", __func__);
1177 	} else
1178 		spin_unlock_irqrestore(&priv->lock, flags);
1179 
1180 	/* process read if there is data other than line status */
1181 	if (bytes > i) {
1182 		tty_insert_flip_string_fixed_flag(&port->port, data + i,
1183 				tty_flag, bytes - i);
1184 		tty_flip_buffer_push(&port->port);
1185 	}
1186 
1187 	spin_lock_irqsave(&priv->lock, flags);
1188 	/* control and status byte(s) are also counted */
1189 	priv->bytes_in += bytes;
1190 	spin_unlock_irqrestore(&priv->lock, flags);
1191 
1192 continue_read:
1193 	tty_kref_put(tty);
1194 
1195 	/* Continue trying to always read */
1196 
1197 	if (priv->comm_is_ok) {
1198 		usb_fill_int_urb(port->interrupt_in_urb, port->serial->dev,
1199 				usb_rcvintpipe(port->serial->dev,
1200 					port->interrupt_in_endpointAddress),
1201 				port->interrupt_in_urb->transfer_buffer,
1202 				port->interrupt_in_urb->transfer_buffer_length,
1203 				cypress_read_int_callback, port,
1204 				priv->read_urb_interval);
1205 		result = usb_submit_urb(port->interrupt_in_urb, GFP_ATOMIC);
1206 		if (result && result != -EPERM) {
1207 			dev_err(dev, "%s - failed resubmitting read urb, error %d\n",
1208 				__func__, result);
1209 			cypress_set_dead(port);
1210 		}
1211 	}
1212 } /* cypress_read_int_callback */
1213 
1214 
1215 static void cypress_write_int_callback(struct urb *urb)
1216 {
1217 	struct usb_serial_port *port = urb->context;
1218 	struct cypress_private *priv = usb_get_serial_port_data(port);
1219 	struct device *dev = &urb->dev->dev;
1220 	int status = urb->status;
1221 
1222 	switch (status) {
1223 	case 0:
1224 		/* success */
1225 		break;
1226 	case -ECONNRESET:
1227 	case -ENOENT:
1228 	case -ESHUTDOWN:
1229 		/* this urb is terminated, clean up */
1230 		dev_dbg(dev, "%s - urb shutting down with status: %d\n",
1231 			__func__, status);
1232 		priv->write_urb_in_use = 0;
1233 		return;
1234 	case -EPIPE:
1235 		/* Cannot call usb_clear_halt while in_interrupt */
1236 		/* FALLTHROUGH */
1237 	default:
1238 		dev_err(dev, "%s - unexpected nonzero write status received: %d\n",
1239 			__func__, status);
1240 		cypress_set_dead(port);
1241 		break;
1242 	}
1243 	priv->write_urb_in_use = 0;
1244 
1245 	/* send any buffered data */
1246 	cypress_send(port);
1247 }
1248 
1249 module_usb_serial_driver(serial_drivers, id_table_combined);
1250 
1251 MODULE_AUTHOR(DRIVER_AUTHOR);
1252 MODULE_DESCRIPTION(DRIVER_DESC);
1253 MODULE_LICENSE("GPL");
1254 
1255 module_param(stats, bool, S_IRUGO | S_IWUSR);
1256 MODULE_PARM_DESC(stats, "Enable statistics or not");
1257 module_param(interval, int, S_IRUGO | S_IWUSR);
1258 MODULE_PARM_DESC(interval, "Overrides interrupt interval");
1259 module_param(unstable_bauds, bool, S_IRUGO | S_IWUSR);
1260 MODULE_PARM_DESC(unstable_bauds, "Allow unstable baud rates");
1261