xref: /openbmc/linux/drivers/usb/serial/cypress_m8.c (revision 0c874100)
1 // SPDX-License-Identifier: GPL-2.0+
2 /*
3  * USB Cypress M8 driver
4  *
5  * 	Copyright (C) 2004
6  * 	    Lonnie Mendez (dignome@gmail.com)
7  *	Copyright (C) 2003,2004
8  *	    Neil Whelchel (koyama@firstlight.net)
9  *
10  * See Documentation/usb/usb-serial.txt for more information on using this
11  * driver
12  *
13  * See http://geocities.com/i0xox0i for information on this driver and the
14  * earthmate usb device.
15  */
16 
17 /* Thanks to Neil Whelchel for writing the first cypress m8 implementation
18    for linux. */
19 /* Thanks to cypress for providing references for the hid reports. */
20 /* Thanks to Jiang Zhang for providing links and for general help. */
21 /* Code originates and was built up from ftdi_sio, belkin, pl2303 and others.*/
22 
23 
24 #include <linux/kernel.h>
25 #include <linux/errno.h>
26 #include <linux/slab.h>
27 #include <linux/tty.h>
28 #include <linux/tty_driver.h>
29 #include <linux/tty_flip.h>
30 #include <linux/module.h>
31 #include <linux/moduleparam.h>
32 #include <linux/spinlock.h>
33 #include <linux/usb.h>
34 #include <linux/usb/serial.h>
35 #include <linux/serial.h>
36 #include <linux/kfifo.h>
37 #include <linux/delay.h>
38 #include <linux/uaccess.h>
39 #include <asm/unaligned.h>
40 
41 #include "cypress_m8.h"
42 
43 
44 static bool stats;
45 static int interval;
46 static bool unstable_bauds;
47 
48 #define DRIVER_AUTHOR "Lonnie Mendez <dignome@gmail.com>, Neil Whelchel <koyama@firstlight.net>"
49 #define DRIVER_DESC "Cypress USB to Serial Driver"
50 
51 /* write buffer size defines */
52 #define CYPRESS_BUF_SIZE	1024
53 
54 static const struct usb_device_id id_table_earthmate[] = {
55 	{ USB_DEVICE(VENDOR_ID_DELORME, PRODUCT_ID_EARTHMATEUSB) },
56 	{ USB_DEVICE(VENDOR_ID_DELORME, PRODUCT_ID_EARTHMATEUSB_LT20) },
57 	{ }						/* Terminating entry */
58 };
59 
60 static const struct usb_device_id id_table_cyphidcomrs232[] = {
61 	{ USB_DEVICE(VENDOR_ID_CYPRESS, PRODUCT_ID_CYPHIDCOM) },
62 	{ USB_DEVICE(VENDOR_ID_POWERCOM, PRODUCT_ID_UPS) },
63 	{ USB_DEVICE(VENDOR_ID_FRWD, PRODUCT_ID_CYPHIDCOM_FRWD) },
64 	{ }						/* Terminating entry */
65 };
66 
67 static const struct usb_device_id id_table_nokiaca42v2[] = {
68 	{ USB_DEVICE(VENDOR_ID_DAZZLE, PRODUCT_ID_CA42) },
69 	{ }						/* Terminating entry */
70 };
71 
72 static const struct usb_device_id id_table_combined[] = {
73 	{ USB_DEVICE(VENDOR_ID_DELORME, PRODUCT_ID_EARTHMATEUSB) },
74 	{ USB_DEVICE(VENDOR_ID_DELORME, PRODUCT_ID_EARTHMATEUSB_LT20) },
75 	{ USB_DEVICE(VENDOR_ID_CYPRESS, PRODUCT_ID_CYPHIDCOM) },
76 	{ USB_DEVICE(VENDOR_ID_POWERCOM, PRODUCT_ID_UPS) },
77 	{ USB_DEVICE(VENDOR_ID_FRWD, PRODUCT_ID_CYPHIDCOM_FRWD) },
78 	{ USB_DEVICE(VENDOR_ID_DAZZLE, PRODUCT_ID_CA42) },
79 	{ }						/* Terminating entry */
80 };
81 
82 MODULE_DEVICE_TABLE(usb, id_table_combined);
83 
84 enum packet_format {
85 	packet_format_1,  /* b0:status, b1:payload count */
86 	packet_format_2   /* b0[7:3]:status, b0[2:0]:payload count */
87 };
88 
89 struct cypress_private {
90 	spinlock_t lock;		   /* private lock */
91 	int chiptype;			   /* identifier of device, for quirks/etc */
92 	int bytes_in;			   /* used for statistics */
93 	int bytes_out;			   /* used for statistics */
94 	int cmd_count;			   /* used for statistics */
95 	int cmd_ctrl;			   /* always set this to 1 before issuing a command */
96 	struct kfifo write_fifo;	   /* write fifo */
97 	int write_urb_in_use;		   /* write urb in use indicator */
98 	int write_urb_interval;            /* interval to use for write urb */
99 	int read_urb_interval;             /* interval to use for read urb */
100 	int comm_is_ok;                    /* true if communication is (still) ok */
101 	int termios_initialized;
102 	__u8 line_control;	   	   /* holds dtr / rts value */
103 	__u8 current_status;	   	   /* received from last read - info on dsr,cts,cd,ri,etc */
104 	__u8 current_config;	   	   /* stores the current configuration byte */
105 	__u8 rx_flags;			   /* throttling - used from whiteheat/ftdi_sio */
106 	enum packet_format pkt_fmt;	   /* format to use for packet send / receive */
107 	int get_cfg_unsafe;		   /* If true, the CYPRESS_GET_CONFIG is unsafe */
108 	int baud_rate;			   /* stores current baud rate in
109 					      integer form */
110 	int isthrottled;		   /* if throttled, discard reads */
111 	char prev_status;		   /* used for TIOCMIWAIT */
112 	/* we pass a pointer to this as the argument sent to
113 	   cypress_set_termios old_termios */
114 	struct ktermios tmp_termios; 	   /* stores the old termios settings */
115 };
116 
117 /* function prototypes for the Cypress USB to serial device */
118 static int  cypress_earthmate_port_probe(struct usb_serial_port *port);
119 static int  cypress_hidcom_port_probe(struct usb_serial_port *port);
120 static int  cypress_ca42v2_port_probe(struct usb_serial_port *port);
121 static int  cypress_port_remove(struct usb_serial_port *port);
122 static int  cypress_open(struct tty_struct *tty, struct usb_serial_port *port);
123 static void cypress_close(struct usb_serial_port *port);
124 static void cypress_dtr_rts(struct usb_serial_port *port, int on);
125 static int  cypress_write(struct tty_struct *tty, struct usb_serial_port *port,
126 			const unsigned char *buf, int count);
127 static void cypress_send(struct usb_serial_port *port);
128 static int  cypress_write_room(struct tty_struct *tty);
129 static void cypress_set_termios(struct tty_struct *tty,
130 			struct usb_serial_port *port, struct ktermios *old);
131 static int  cypress_tiocmget(struct tty_struct *tty);
132 static int  cypress_tiocmset(struct tty_struct *tty,
133 			unsigned int set, unsigned int clear);
134 static int  cypress_chars_in_buffer(struct tty_struct *tty);
135 static void cypress_throttle(struct tty_struct *tty);
136 static void cypress_unthrottle(struct tty_struct *tty);
137 static void cypress_set_dead(struct usb_serial_port *port);
138 static void cypress_read_int_callback(struct urb *urb);
139 static void cypress_write_int_callback(struct urb *urb);
140 
141 static struct usb_serial_driver cypress_earthmate_device = {
142 	.driver = {
143 		.owner =		THIS_MODULE,
144 		.name =			"earthmate",
145 	},
146 	.description =			"DeLorme Earthmate USB",
147 	.id_table =			id_table_earthmate,
148 	.num_ports =			1,
149 	.port_probe =			cypress_earthmate_port_probe,
150 	.port_remove =			cypress_port_remove,
151 	.open =				cypress_open,
152 	.close =			cypress_close,
153 	.dtr_rts =			cypress_dtr_rts,
154 	.write =			cypress_write,
155 	.write_room =			cypress_write_room,
156 	.set_termios =			cypress_set_termios,
157 	.tiocmget =			cypress_tiocmget,
158 	.tiocmset =			cypress_tiocmset,
159 	.tiocmiwait =			usb_serial_generic_tiocmiwait,
160 	.chars_in_buffer =		cypress_chars_in_buffer,
161 	.throttle =		 	cypress_throttle,
162 	.unthrottle =			cypress_unthrottle,
163 	.read_int_callback =		cypress_read_int_callback,
164 	.write_int_callback =		cypress_write_int_callback,
165 };
166 
167 static struct usb_serial_driver cypress_hidcom_device = {
168 	.driver = {
169 		.owner =		THIS_MODULE,
170 		.name =			"cyphidcom",
171 	},
172 	.description =			"HID->COM RS232 Adapter",
173 	.id_table =			id_table_cyphidcomrs232,
174 	.num_ports =			1,
175 	.port_probe =			cypress_hidcom_port_probe,
176 	.port_remove =			cypress_port_remove,
177 	.open =				cypress_open,
178 	.close =			cypress_close,
179 	.dtr_rts =			cypress_dtr_rts,
180 	.write =			cypress_write,
181 	.write_room =			cypress_write_room,
182 	.set_termios =			cypress_set_termios,
183 	.tiocmget =			cypress_tiocmget,
184 	.tiocmset =			cypress_tiocmset,
185 	.tiocmiwait =			usb_serial_generic_tiocmiwait,
186 	.chars_in_buffer =		cypress_chars_in_buffer,
187 	.throttle =			cypress_throttle,
188 	.unthrottle =			cypress_unthrottle,
189 	.read_int_callback =		cypress_read_int_callback,
190 	.write_int_callback =		cypress_write_int_callback,
191 };
192 
193 static struct usb_serial_driver cypress_ca42v2_device = {
194 	.driver = {
195 		.owner =		THIS_MODULE,
196 		.name =			"nokiaca42v2",
197 	},
198 	.description =			"Nokia CA-42 V2 Adapter",
199 	.id_table =			id_table_nokiaca42v2,
200 	.num_ports =			1,
201 	.port_probe =			cypress_ca42v2_port_probe,
202 	.port_remove =			cypress_port_remove,
203 	.open =				cypress_open,
204 	.close =			cypress_close,
205 	.dtr_rts =			cypress_dtr_rts,
206 	.write =			cypress_write,
207 	.write_room =			cypress_write_room,
208 	.set_termios =			cypress_set_termios,
209 	.tiocmget =			cypress_tiocmget,
210 	.tiocmset =			cypress_tiocmset,
211 	.tiocmiwait =			usb_serial_generic_tiocmiwait,
212 	.chars_in_buffer =		cypress_chars_in_buffer,
213 	.throttle =			cypress_throttle,
214 	.unthrottle =			cypress_unthrottle,
215 	.read_int_callback =		cypress_read_int_callback,
216 	.write_int_callback =		cypress_write_int_callback,
217 };
218 
219 static struct usb_serial_driver * const serial_drivers[] = {
220 	&cypress_earthmate_device, &cypress_hidcom_device,
221 	&cypress_ca42v2_device, NULL
222 };
223 
224 /*****************************************************************************
225  * Cypress serial helper functions
226  *****************************************************************************/
227 
228 /* FRWD Dongle hidcom needs to skip reset and speed checks */
229 static inline bool is_frwd(struct usb_device *dev)
230 {
231 	return ((le16_to_cpu(dev->descriptor.idVendor) == VENDOR_ID_FRWD) &&
232 		(le16_to_cpu(dev->descriptor.idProduct) == PRODUCT_ID_CYPHIDCOM_FRWD));
233 }
234 
235 static int analyze_baud_rate(struct usb_serial_port *port, speed_t new_rate)
236 {
237 	struct cypress_private *priv;
238 	priv = usb_get_serial_port_data(port);
239 
240 	if (unstable_bauds)
241 		return new_rate;
242 
243 	/* FRWD Dongle uses 115200 bps */
244 	if (is_frwd(port->serial->dev))
245 		return new_rate;
246 
247 	/*
248 	 * The general purpose firmware for the Cypress M8 allows for
249 	 * a maximum speed of 57600bps (I have no idea whether DeLorme
250 	 * chose to use the general purpose firmware or not), if you
251 	 * need to modify this speed setting for your own project
252 	 * please add your own chiptype and modify the code likewise.
253 	 * The Cypress HID->COM device will work successfully up to
254 	 * 115200bps (but the actual throughput is around 3kBps).
255 	 */
256 	if (port->serial->dev->speed == USB_SPEED_LOW) {
257 		/*
258 		 * Mike Isely <isely@pobox.com> 2-Feb-2008: The
259 		 * Cypress app note that describes this mechanism
260 		 * states the the low-speed part can't handle more
261 		 * than 800 bytes/sec, in which case 4800 baud is the
262 		 * safest speed for a part like that.
263 		 */
264 		if (new_rate > 4800) {
265 			dev_dbg(&port->dev,
266 				"%s - failed setting baud rate, device incapable speed %d\n",
267 				__func__, new_rate);
268 			return -1;
269 		}
270 	}
271 	switch (priv->chiptype) {
272 	case CT_EARTHMATE:
273 		if (new_rate <= 600) {
274 			/* 300 and 600 baud rates are supported under
275 			 * the generic firmware, but are not used with
276 			 * NMEA and SiRF protocols */
277 			dev_dbg(&port->dev,
278 				"%s - failed setting baud rate, unsupported speed of %d on Earthmate GPS\n",
279 				__func__, new_rate);
280 			return -1;
281 		}
282 		break;
283 	default:
284 		break;
285 	}
286 	return new_rate;
287 }
288 
289 
290 /* This function can either set or retrieve the current serial line settings */
291 static int cypress_serial_control(struct tty_struct *tty,
292 	struct usb_serial_port *port, speed_t baud_rate, int data_bits,
293 	int stop_bits, int parity_enable, int parity_type, int reset,
294 	int cypress_request_type)
295 {
296 	int new_baudrate = 0, retval = 0, tries = 0;
297 	struct cypress_private *priv;
298 	struct device *dev = &port->dev;
299 	u8 *feature_buffer;
300 	const unsigned int feature_len = 5;
301 	unsigned long flags;
302 
303 	priv = usb_get_serial_port_data(port);
304 
305 	if (!priv->comm_is_ok)
306 		return -ENODEV;
307 
308 	feature_buffer = kcalloc(feature_len, sizeof(u8), GFP_KERNEL);
309 	if (!feature_buffer)
310 		return -ENOMEM;
311 
312 	switch (cypress_request_type) {
313 	case CYPRESS_SET_CONFIG:
314 		/* 0 means 'Hang up' so doesn't change the true bit rate */
315 		new_baudrate = priv->baud_rate;
316 		if (baud_rate && baud_rate != priv->baud_rate) {
317 			dev_dbg(dev, "%s - baud rate is changing\n", __func__);
318 			retval = analyze_baud_rate(port, baud_rate);
319 			if (retval >= 0) {
320 				new_baudrate = retval;
321 				dev_dbg(dev, "%s - New baud rate set to %d\n",
322 					__func__, new_baudrate);
323 			}
324 		}
325 		dev_dbg(dev, "%s - baud rate is being sent as %d\n", __func__,
326 			new_baudrate);
327 
328 		/* fill the feature_buffer with new configuration */
329 		put_unaligned_le32(new_baudrate, feature_buffer);
330 		feature_buffer[4] |= data_bits;   /* assign data bits in 2 bit space ( max 3 ) */
331 		/* 1 bit gap */
332 		feature_buffer[4] |= (stop_bits << 3);   /* assign stop bits in 1 bit space */
333 		feature_buffer[4] |= (parity_enable << 4);   /* assign parity flag in 1 bit space */
334 		feature_buffer[4] |= (parity_type << 5);   /* assign parity type in 1 bit space */
335 		/* 1 bit gap */
336 		feature_buffer[4] |= (reset << 7);   /* assign reset at end of byte, 1 bit space */
337 
338 		dev_dbg(dev, "%s - device is being sent this feature report:\n", __func__);
339 		dev_dbg(dev, "%s - %02X - %02X - %02X - %02X - %02X\n", __func__,
340 			feature_buffer[0], feature_buffer[1],
341 			feature_buffer[2], feature_buffer[3],
342 			feature_buffer[4]);
343 
344 		do {
345 			retval = usb_control_msg(port->serial->dev,
346 					usb_sndctrlpipe(port->serial->dev, 0),
347 					HID_REQ_SET_REPORT,
348 					USB_DIR_OUT | USB_RECIP_INTERFACE | USB_TYPE_CLASS,
349 					0x0300, 0, feature_buffer,
350 					feature_len, 500);
351 
352 			if (tries++ >= 3)
353 				break;
354 
355 		} while (retval != feature_len &&
356 			 retval != -ENODEV);
357 
358 		if (retval != feature_len) {
359 			dev_err(dev, "%s - failed sending serial line settings - %d\n",
360 				__func__, retval);
361 			cypress_set_dead(port);
362 		} else {
363 			spin_lock_irqsave(&priv->lock, flags);
364 			priv->baud_rate = new_baudrate;
365 			priv->current_config = feature_buffer[4];
366 			spin_unlock_irqrestore(&priv->lock, flags);
367 			/* If we asked for a speed change encode it */
368 			if (baud_rate)
369 				tty_encode_baud_rate(tty,
370 					new_baudrate, new_baudrate);
371 		}
372 	break;
373 	case CYPRESS_GET_CONFIG:
374 		if (priv->get_cfg_unsafe) {
375 			/* Not implemented for this device,
376 			   and if we try to do it we're likely
377 			   to crash the hardware. */
378 			retval = -ENOTTY;
379 			goto out;
380 		}
381 		dev_dbg(dev, "%s - retrieving serial line settings\n", __func__);
382 		do {
383 			retval = usb_control_msg(port->serial->dev,
384 					usb_rcvctrlpipe(port->serial->dev, 0),
385 					HID_REQ_GET_REPORT,
386 					USB_DIR_IN | USB_RECIP_INTERFACE | USB_TYPE_CLASS,
387 					0x0300, 0, feature_buffer,
388 					feature_len, 500);
389 
390 			if (tries++ >= 3)
391 				break;
392 		} while (retval != feature_len
393 						&& retval != -ENODEV);
394 
395 		if (retval != feature_len) {
396 			dev_err(dev, "%s - failed to retrieve serial line settings - %d\n",
397 				__func__, retval);
398 			cypress_set_dead(port);
399 			goto out;
400 		} else {
401 			spin_lock_irqsave(&priv->lock, flags);
402 			/* store the config in one byte, and later
403 			   use bit masks to check values */
404 			priv->current_config = feature_buffer[4];
405 			priv->baud_rate = get_unaligned_le32(feature_buffer);
406 			spin_unlock_irqrestore(&priv->lock, flags);
407 		}
408 	}
409 	spin_lock_irqsave(&priv->lock, flags);
410 	++priv->cmd_count;
411 	spin_unlock_irqrestore(&priv->lock, flags);
412 out:
413 	kfree(feature_buffer);
414 	return retval;
415 } /* cypress_serial_control */
416 
417 
418 static void cypress_set_dead(struct usb_serial_port *port)
419 {
420 	struct cypress_private *priv = usb_get_serial_port_data(port);
421 	unsigned long flags;
422 
423 	spin_lock_irqsave(&priv->lock, flags);
424 	if (!priv->comm_is_ok) {
425 		spin_unlock_irqrestore(&priv->lock, flags);
426 		return;
427 	}
428 	priv->comm_is_ok = 0;
429 	spin_unlock_irqrestore(&priv->lock, flags);
430 
431 	dev_err(&port->dev, "cypress_m8 suspending failing port %d - "
432 		"interval might be too short\n", port->port_number);
433 }
434 
435 
436 /*****************************************************************************
437  * Cypress serial driver functions
438  *****************************************************************************/
439 
440 
441 static int cypress_generic_port_probe(struct usb_serial_port *port)
442 {
443 	struct usb_serial *serial = port->serial;
444 	struct cypress_private *priv;
445 
446 	if (!port->interrupt_out_urb || !port->interrupt_in_urb) {
447 		dev_err(&port->dev, "required endpoint is missing\n");
448 		return -ENODEV;
449 	}
450 
451 	priv = kzalloc(sizeof(struct cypress_private), GFP_KERNEL);
452 	if (!priv)
453 		return -ENOMEM;
454 
455 	priv->comm_is_ok = !0;
456 	spin_lock_init(&priv->lock);
457 	if (kfifo_alloc(&priv->write_fifo, CYPRESS_BUF_SIZE, GFP_KERNEL)) {
458 		kfree(priv);
459 		return -ENOMEM;
460 	}
461 
462 	/* Skip reset for FRWD device. It is a workaound:
463 	   device hangs if it receives SET_CONFIGURE in Configured
464 	   state. */
465 	if (!is_frwd(serial->dev))
466 		usb_reset_configuration(serial->dev);
467 
468 	priv->cmd_ctrl = 0;
469 	priv->line_control = 0;
470 	priv->termios_initialized = 0;
471 	priv->rx_flags = 0;
472 	/* Default packet format setting is determined by packet size.
473 	   Anything with a size larger then 9 must have a separate
474 	   count field since the 3 bit count field is otherwise too
475 	   small.  Otherwise we can use the slightly more compact
476 	   format.  This is in accordance with the cypress_m8 serial
477 	   converter app note. */
478 	if (port->interrupt_out_size > 9)
479 		priv->pkt_fmt = packet_format_1;
480 	else
481 		priv->pkt_fmt = packet_format_2;
482 
483 	if (interval > 0) {
484 		priv->write_urb_interval = interval;
485 		priv->read_urb_interval = interval;
486 		dev_dbg(&port->dev, "%s - read & write intervals forced to %d\n",
487 			__func__, interval);
488 	} else {
489 		priv->write_urb_interval = port->interrupt_out_urb->interval;
490 		priv->read_urb_interval = port->interrupt_in_urb->interval;
491 		dev_dbg(&port->dev, "%s - intervals: read=%d write=%d\n",
492 			__func__, priv->read_urb_interval,
493 			priv->write_urb_interval);
494 	}
495 	usb_set_serial_port_data(port, priv);
496 
497 	port->port.drain_delay = 256;
498 
499 	return 0;
500 }
501 
502 
503 static int cypress_earthmate_port_probe(struct usb_serial_port *port)
504 {
505 	struct usb_serial *serial = port->serial;
506 	struct cypress_private *priv;
507 	int ret;
508 
509 	ret = cypress_generic_port_probe(port);
510 	if (ret) {
511 		dev_dbg(&port->dev, "%s - Failed setting up port\n", __func__);
512 		return ret;
513 	}
514 
515 	priv = usb_get_serial_port_data(port);
516 	priv->chiptype = CT_EARTHMATE;
517 	/* All Earthmate devices use the separated-count packet
518 	   format!  Idiotic. */
519 	priv->pkt_fmt = packet_format_1;
520 	if (serial->dev->descriptor.idProduct !=
521 				cpu_to_le16(PRODUCT_ID_EARTHMATEUSB)) {
522 		/* The old original USB Earthmate seemed able to
523 		   handle GET_CONFIG requests; everything they've
524 		   produced since that time crashes if this command is
525 		   attempted :-( */
526 		dev_dbg(&port->dev,
527 			"%s - Marking this device as unsafe for GET_CONFIG commands\n",
528 			__func__);
529 		priv->get_cfg_unsafe = !0;
530 	}
531 
532 	return 0;
533 }
534 
535 static int cypress_hidcom_port_probe(struct usb_serial_port *port)
536 {
537 	struct cypress_private *priv;
538 	int ret;
539 
540 	ret = cypress_generic_port_probe(port);
541 	if (ret) {
542 		dev_dbg(&port->dev, "%s - Failed setting up port\n", __func__);
543 		return ret;
544 	}
545 
546 	priv = usb_get_serial_port_data(port);
547 	priv->chiptype = CT_CYPHIDCOM;
548 
549 	return 0;
550 }
551 
552 static int cypress_ca42v2_port_probe(struct usb_serial_port *port)
553 {
554 	struct cypress_private *priv;
555 	int ret;
556 
557 	ret = cypress_generic_port_probe(port);
558 	if (ret) {
559 		dev_dbg(&port->dev, "%s - Failed setting up port\n", __func__);
560 		return ret;
561 	}
562 
563 	priv = usb_get_serial_port_data(port);
564 	priv->chiptype = CT_CA42V2;
565 
566 	return 0;
567 }
568 
569 static int cypress_port_remove(struct usb_serial_port *port)
570 {
571 	struct cypress_private *priv;
572 
573 	priv = usb_get_serial_port_data(port);
574 
575 	kfifo_free(&priv->write_fifo);
576 	kfree(priv);
577 
578 	return 0;
579 }
580 
581 static int cypress_open(struct tty_struct *tty, struct usb_serial_port *port)
582 {
583 	struct cypress_private *priv = usb_get_serial_port_data(port);
584 	struct usb_serial *serial = port->serial;
585 	unsigned long flags;
586 	int result = 0;
587 
588 	if (!priv->comm_is_ok)
589 		return -EIO;
590 
591 	/* clear halts before open */
592 	usb_clear_halt(serial->dev, 0x81);
593 	usb_clear_halt(serial->dev, 0x02);
594 
595 	spin_lock_irqsave(&priv->lock, flags);
596 	/* reset read/write statistics */
597 	priv->bytes_in = 0;
598 	priv->bytes_out = 0;
599 	priv->cmd_count = 0;
600 	priv->rx_flags = 0;
601 	spin_unlock_irqrestore(&priv->lock, flags);
602 
603 	/* Set termios */
604 	cypress_send(port);
605 
606 	if (tty)
607 		cypress_set_termios(tty, port, &priv->tmp_termios);
608 
609 	/* setup the port and start reading from the device */
610 	usb_fill_int_urb(port->interrupt_in_urb, serial->dev,
611 		usb_rcvintpipe(serial->dev, port->interrupt_in_endpointAddress),
612 		port->interrupt_in_urb->transfer_buffer,
613 		port->interrupt_in_urb->transfer_buffer_length,
614 		cypress_read_int_callback, port, priv->read_urb_interval);
615 	result = usb_submit_urb(port->interrupt_in_urb, GFP_KERNEL);
616 
617 	if (result) {
618 		dev_err(&port->dev,
619 			"%s - failed submitting read urb, error %d\n",
620 							__func__, result);
621 		cypress_set_dead(port);
622 	}
623 
624 	return result;
625 } /* cypress_open */
626 
627 static void cypress_dtr_rts(struct usb_serial_port *port, int on)
628 {
629 	struct cypress_private *priv = usb_get_serial_port_data(port);
630 	/* drop dtr and rts */
631 	spin_lock_irq(&priv->lock);
632 	if (on == 0)
633 		priv->line_control = 0;
634 	else
635 		priv->line_control = CONTROL_DTR | CONTROL_RTS;
636 	priv->cmd_ctrl = 1;
637 	spin_unlock_irq(&priv->lock);
638 	cypress_write(NULL, port, NULL, 0);
639 }
640 
641 static void cypress_close(struct usb_serial_port *port)
642 {
643 	struct cypress_private *priv = usb_get_serial_port_data(port);
644 	unsigned long flags;
645 
646 	spin_lock_irqsave(&priv->lock, flags);
647 	kfifo_reset_out(&priv->write_fifo);
648 	spin_unlock_irqrestore(&priv->lock, flags);
649 
650 	dev_dbg(&port->dev, "%s - stopping urbs\n", __func__);
651 	usb_kill_urb(port->interrupt_in_urb);
652 	usb_kill_urb(port->interrupt_out_urb);
653 
654 	if (stats)
655 		dev_info(&port->dev, "Statistics: %d Bytes In | %d Bytes Out | %d Commands Issued\n",
656 			priv->bytes_in, priv->bytes_out, priv->cmd_count);
657 } /* cypress_close */
658 
659 
660 static int cypress_write(struct tty_struct *tty, struct usb_serial_port *port,
661 					const unsigned char *buf, int count)
662 {
663 	struct cypress_private *priv = usb_get_serial_port_data(port);
664 
665 	dev_dbg(&port->dev, "%s - %d bytes\n", __func__, count);
666 
667 	/* line control commands, which need to be executed immediately,
668 	   are not put into the buffer for obvious reasons.
669 	 */
670 	if (priv->cmd_ctrl) {
671 		count = 0;
672 		goto finish;
673 	}
674 
675 	if (!count)
676 		return count;
677 
678 	count = kfifo_in_locked(&priv->write_fifo, buf, count, &priv->lock);
679 
680 finish:
681 	cypress_send(port);
682 
683 	return count;
684 } /* cypress_write */
685 
686 
687 static void cypress_send(struct usb_serial_port *port)
688 {
689 	int count = 0, result, offset, actual_size;
690 	struct cypress_private *priv = usb_get_serial_port_data(port);
691 	struct device *dev = &port->dev;
692 	unsigned long flags;
693 
694 	if (!priv->comm_is_ok)
695 		return;
696 
697 	dev_dbg(dev, "%s - interrupt out size is %d\n", __func__,
698 		port->interrupt_out_size);
699 
700 	spin_lock_irqsave(&priv->lock, flags);
701 	if (priv->write_urb_in_use) {
702 		dev_dbg(dev, "%s - can't write, urb in use\n", __func__);
703 		spin_unlock_irqrestore(&priv->lock, flags);
704 		return;
705 	}
706 	spin_unlock_irqrestore(&priv->lock, flags);
707 
708 	/* clear buffer */
709 	memset(port->interrupt_out_urb->transfer_buffer, 0,
710 						port->interrupt_out_size);
711 
712 	spin_lock_irqsave(&priv->lock, flags);
713 	switch (priv->pkt_fmt) {
714 	default:
715 	case packet_format_1:
716 		/* this is for the CY7C64013... */
717 		offset = 2;
718 		port->interrupt_out_buffer[0] = priv->line_control;
719 		break;
720 	case packet_format_2:
721 		/* this is for the CY7C63743... */
722 		offset = 1;
723 		port->interrupt_out_buffer[0] = priv->line_control;
724 		break;
725 	}
726 
727 	if (priv->line_control & CONTROL_RESET)
728 		priv->line_control &= ~CONTROL_RESET;
729 
730 	if (priv->cmd_ctrl) {
731 		priv->cmd_count++;
732 		dev_dbg(dev, "%s - line control command being issued\n", __func__);
733 		spin_unlock_irqrestore(&priv->lock, flags);
734 		goto send;
735 	} else
736 		spin_unlock_irqrestore(&priv->lock, flags);
737 
738 	count = kfifo_out_locked(&priv->write_fifo,
739 					&port->interrupt_out_buffer[offset],
740 					port->interrupt_out_size - offset,
741 					&priv->lock);
742 	if (count == 0)
743 		return;
744 
745 	switch (priv->pkt_fmt) {
746 	default:
747 	case packet_format_1:
748 		port->interrupt_out_buffer[1] = count;
749 		break;
750 	case packet_format_2:
751 		port->interrupt_out_buffer[0] |= count;
752 	}
753 
754 	dev_dbg(dev, "%s - count is %d\n", __func__, count);
755 
756 send:
757 	spin_lock_irqsave(&priv->lock, flags);
758 	priv->write_urb_in_use = 1;
759 	spin_unlock_irqrestore(&priv->lock, flags);
760 
761 	if (priv->cmd_ctrl)
762 		actual_size = 1;
763 	else
764 		actual_size = count +
765 			      (priv->pkt_fmt == packet_format_1 ? 2 : 1);
766 
767 	usb_serial_debug_data(dev, __func__, port->interrupt_out_size,
768 			      port->interrupt_out_urb->transfer_buffer);
769 
770 	usb_fill_int_urb(port->interrupt_out_urb, port->serial->dev,
771 		usb_sndintpipe(port->serial->dev, port->interrupt_out_endpointAddress),
772 		port->interrupt_out_buffer, actual_size,
773 		cypress_write_int_callback, port, priv->write_urb_interval);
774 	result = usb_submit_urb(port->interrupt_out_urb, GFP_ATOMIC);
775 	if (result) {
776 		dev_err_console(port,
777 				"%s - failed submitting write urb, error %d\n",
778 							__func__, result);
779 		priv->write_urb_in_use = 0;
780 		cypress_set_dead(port);
781 	}
782 
783 	spin_lock_irqsave(&priv->lock, flags);
784 	if (priv->cmd_ctrl)
785 		priv->cmd_ctrl = 0;
786 
787 	/* do not count the line control and size bytes */
788 	priv->bytes_out += count;
789 	spin_unlock_irqrestore(&priv->lock, flags);
790 
791 	usb_serial_port_softint(port);
792 } /* cypress_send */
793 
794 
795 /* returns how much space is available in the soft buffer */
796 static int cypress_write_room(struct tty_struct *tty)
797 {
798 	struct usb_serial_port *port = tty->driver_data;
799 	struct cypress_private *priv = usb_get_serial_port_data(port);
800 	int room = 0;
801 	unsigned long flags;
802 
803 	spin_lock_irqsave(&priv->lock, flags);
804 	room = kfifo_avail(&priv->write_fifo);
805 	spin_unlock_irqrestore(&priv->lock, flags);
806 
807 	dev_dbg(&port->dev, "%s - returns %d\n", __func__, room);
808 	return room;
809 }
810 
811 
812 static int cypress_tiocmget(struct tty_struct *tty)
813 {
814 	struct usb_serial_port *port = tty->driver_data;
815 	struct cypress_private *priv = usb_get_serial_port_data(port);
816 	__u8 status, control;
817 	unsigned int result = 0;
818 	unsigned long flags;
819 
820 	spin_lock_irqsave(&priv->lock, flags);
821 	control = priv->line_control;
822 	status = priv->current_status;
823 	spin_unlock_irqrestore(&priv->lock, flags);
824 
825 	result = ((control & CONTROL_DTR)        ? TIOCM_DTR : 0)
826 		| ((control & CONTROL_RTS)       ? TIOCM_RTS : 0)
827 		| ((status & UART_CTS)        ? TIOCM_CTS : 0)
828 		| ((status & UART_DSR)        ? TIOCM_DSR : 0)
829 		| ((status & UART_RI)         ? TIOCM_RI  : 0)
830 		| ((status & UART_CD)         ? TIOCM_CD  : 0);
831 
832 	dev_dbg(&port->dev, "%s - result = %x\n", __func__, result);
833 
834 	return result;
835 }
836 
837 
838 static int cypress_tiocmset(struct tty_struct *tty,
839 			       unsigned int set, unsigned int clear)
840 {
841 	struct usb_serial_port *port = tty->driver_data;
842 	struct cypress_private *priv = usb_get_serial_port_data(port);
843 	unsigned long flags;
844 
845 	spin_lock_irqsave(&priv->lock, flags);
846 	if (set & TIOCM_RTS)
847 		priv->line_control |= CONTROL_RTS;
848 	if (set & TIOCM_DTR)
849 		priv->line_control |= CONTROL_DTR;
850 	if (clear & TIOCM_RTS)
851 		priv->line_control &= ~CONTROL_RTS;
852 	if (clear & TIOCM_DTR)
853 		priv->line_control &= ~CONTROL_DTR;
854 	priv->cmd_ctrl = 1;
855 	spin_unlock_irqrestore(&priv->lock, flags);
856 
857 	return cypress_write(tty, port, NULL, 0);
858 }
859 
860 static void cypress_set_termios(struct tty_struct *tty,
861 	struct usb_serial_port *port, struct ktermios *old_termios)
862 {
863 	struct cypress_private *priv = usb_get_serial_port_data(port);
864 	struct device *dev = &port->dev;
865 	int data_bits, stop_bits, parity_type, parity_enable;
866 	unsigned int cflag;
867 	unsigned long flags;
868 	__u8 oldlines;
869 	int linechange = 0;
870 
871 	spin_lock_irqsave(&priv->lock, flags);
872 	/* We can't clean this one up as we don't know the device type
873 	   early enough */
874 	if (!priv->termios_initialized) {
875 		if (priv->chiptype == CT_EARTHMATE) {
876 			tty->termios = tty_std_termios;
877 			tty->termios.c_cflag = B4800 | CS8 | CREAD | HUPCL |
878 				CLOCAL;
879 			tty->termios.c_ispeed = 4800;
880 			tty->termios.c_ospeed = 4800;
881 		} else if (priv->chiptype == CT_CYPHIDCOM) {
882 			tty->termios = tty_std_termios;
883 			tty->termios.c_cflag = B9600 | CS8 | CREAD | HUPCL |
884 				CLOCAL;
885 			tty->termios.c_ispeed = 9600;
886 			tty->termios.c_ospeed = 9600;
887 		} else if (priv->chiptype == CT_CA42V2) {
888 			tty->termios = tty_std_termios;
889 			tty->termios.c_cflag = B9600 | CS8 | CREAD | HUPCL |
890 				CLOCAL;
891 			tty->termios.c_ispeed = 9600;
892 			tty->termios.c_ospeed = 9600;
893 		}
894 		priv->termios_initialized = 1;
895 	}
896 	spin_unlock_irqrestore(&priv->lock, flags);
897 
898 	/* Unsupported features need clearing */
899 	tty->termios.c_cflag &= ~(CMSPAR|CRTSCTS);
900 
901 	cflag = tty->termios.c_cflag;
902 
903 	/* check if there are new settings */
904 	if (old_termios) {
905 		spin_lock_irqsave(&priv->lock, flags);
906 		priv->tmp_termios = tty->termios;
907 		spin_unlock_irqrestore(&priv->lock, flags);
908 	}
909 
910 	/* set number of data bits, parity, stop bits */
911 	/* when parity is disabled the parity type bit is ignored */
912 
913 	/* 1 means 2 stop bits, 0 means 1 stop bit */
914 	stop_bits = cflag & CSTOPB ? 1 : 0;
915 
916 	if (cflag & PARENB) {
917 		parity_enable = 1;
918 		/* 1 means odd parity, 0 means even parity */
919 		parity_type = cflag & PARODD ? 1 : 0;
920 	} else
921 		parity_enable = parity_type = 0;
922 
923 	switch (cflag & CSIZE) {
924 	case CS5:
925 		data_bits = 0;
926 		break;
927 	case CS6:
928 		data_bits = 1;
929 		break;
930 	case CS7:
931 		data_bits = 2;
932 		break;
933 	case CS8:
934 		data_bits = 3;
935 		break;
936 	default:
937 		dev_err(dev, "%s - CSIZE was set, but not CS5-CS8\n", __func__);
938 		data_bits = 3;
939 	}
940 	spin_lock_irqsave(&priv->lock, flags);
941 	oldlines = priv->line_control;
942 	if ((cflag & CBAUD) == B0) {
943 		/* drop dtr and rts */
944 		dev_dbg(dev, "%s - dropping the lines, baud rate 0bps\n", __func__);
945 		priv->line_control &= ~(CONTROL_DTR | CONTROL_RTS);
946 	} else
947 		priv->line_control = (CONTROL_DTR | CONTROL_RTS);
948 	spin_unlock_irqrestore(&priv->lock, flags);
949 
950 	dev_dbg(dev, "%s - sending %d stop_bits, %d parity_enable, %d parity_type, %d data_bits (+5)\n",
951 		__func__, stop_bits, parity_enable, parity_type, data_bits);
952 
953 	cypress_serial_control(tty, port, tty_get_baud_rate(tty),
954 			data_bits, stop_bits,
955 			parity_enable, parity_type,
956 			0, CYPRESS_SET_CONFIG);
957 
958 	/* we perform a CYPRESS_GET_CONFIG so that the current settings are
959 	 * filled into the private structure this should confirm that all is
960 	 * working if it returns what we just set */
961 	cypress_serial_control(tty, port, 0, 0, 0, 0, 0, 0, CYPRESS_GET_CONFIG);
962 
963 	/* Here we can define custom tty settings for devices; the main tty
964 	 * termios flag base comes from empeg.c */
965 
966 	spin_lock_irqsave(&priv->lock, flags);
967 	if (priv->chiptype == CT_EARTHMATE && priv->baud_rate == 4800) {
968 		dev_dbg(dev, "Using custom termios settings for a baud rate of 4800bps.\n");
969 		/* define custom termios settings for NMEA protocol */
970 
971 		tty->termios.c_iflag /* input modes - */
972 			&= ~(IGNBRK  /* disable ignore break */
973 			| BRKINT     /* disable break causes interrupt */
974 			| PARMRK     /* disable mark parity errors */
975 			| ISTRIP     /* disable clear high bit of input char */
976 			| INLCR      /* disable translate NL to CR */
977 			| IGNCR      /* disable ignore CR */
978 			| ICRNL      /* disable translate CR to NL */
979 			| IXON);     /* disable enable XON/XOFF flow control */
980 
981 		tty->termios.c_oflag /* output modes */
982 			&= ~OPOST;    /* disable postprocess output char */
983 
984 		tty->termios.c_lflag /* line discipline modes */
985 			&= ~(ECHO     /* disable echo input characters */
986 			| ECHONL      /* disable echo new line */
987 			| ICANON      /* disable erase, kill, werase, and rprnt
988 					 special characters */
989 			| ISIG        /* disable interrupt, quit, and suspend
990 					 special characters */
991 			| IEXTEN);    /* disable non-POSIX special characters */
992 	} /* CT_CYPHIDCOM: Application should handle this for device */
993 
994 	linechange = (priv->line_control != oldlines);
995 	spin_unlock_irqrestore(&priv->lock, flags);
996 
997 	/* if necessary, set lines */
998 	if (linechange) {
999 		priv->cmd_ctrl = 1;
1000 		cypress_write(tty, port, NULL, 0);
1001 	}
1002 } /* cypress_set_termios */
1003 
1004 
1005 /* returns amount of data still left in soft buffer */
1006 static int cypress_chars_in_buffer(struct tty_struct *tty)
1007 {
1008 	struct usb_serial_port *port = tty->driver_data;
1009 	struct cypress_private *priv = usb_get_serial_port_data(port);
1010 	int chars = 0;
1011 	unsigned long flags;
1012 
1013 	spin_lock_irqsave(&priv->lock, flags);
1014 	chars = kfifo_len(&priv->write_fifo);
1015 	spin_unlock_irqrestore(&priv->lock, flags);
1016 
1017 	dev_dbg(&port->dev, "%s - returns %d\n", __func__, chars);
1018 	return chars;
1019 }
1020 
1021 
1022 static void cypress_throttle(struct tty_struct *tty)
1023 {
1024 	struct usb_serial_port *port = tty->driver_data;
1025 	struct cypress_private *priv = usb_get_serial_port_data(port);
1026 
1027 	spin_lock_irq(&priv->lock);
1028 	priv->rx_flags = THROTTLED;
1029 	spin_unlock_irq(&priv->lock);
1030 }
1031 
1032 
1033 static void cypress_unthrottle(struct tty_struct *tty)
1034 {
1035 	struct usb_serial_port *port = tty->driver_data;
1036 	struct cypress_private *priv = usb_get_serial_port_data(port);
1037 	int actually_throttled, result;
1038 
1039 	spin_lock_irq(&priv->lock);
1040 	actually_throttled = priv->rx_flags & ACTUALLY_THROTTLED;
1041 	priv->rx_flags = 0;
1042 	spin_unlock_irq(&priv->lock);
1043 
1044 	if (!priv->comm_is_ok)
1045 		return;
1046 
1047 	if (actually_throttled) {
1048 		result = usb_submit_urb(port->interrupt_in_urb, GFP_KERNEL);
1049 		if (result) {
1050 			dev_err(&port->dev, "%s - failed submitting read urb, "
1051 					"error %d\n", __func__, result);
1052 			cypress_set_dead(port);
1053 		}
1054 	}
1055 }
1056 
1057 
1058 static void cypress_read_int_callback(struct urb *urb)
1059 {
1060 	struct usb_serial_port *port = urb->context;
1061 	struct cypress_private *priv = usb_get_serial_port_data(port);
1062 	struct device *dev = &urb->dev->dev;
1063 	struct tty_struct *tty;
1064 	unsigned char *data = urb->transfer_buffer;
1065 	unsigned long flags;
1066 	char tty_flag = TTY_NORMAL;
1067 	int bytes = 0;
1068 	int result;
1069 	int i = 0;
1070 	int status = urb->status;
1071 
1072 	switch (status) {
1073 	case 0: /* success */
1074 		break;
1075 	case -ECONNRESET:
1076 	case -ENOENT:
1077 	case -ESHUTDOWN:
1078 		/* precursor to disconnect so just go away */
1079 		return;
1080 	case -EPIPE:
1081 		/* Can't call usb_clear_halt while in_interrupt */
1082 		/* FALLS THROUGH */
1083 	default:
1084 		/* something ugly is going on... */
1085 		dev_err(dev, "%s - unexpected nonzero read status received: %d\n",
1086 			__func__, status);
1087 		cypress_set_dead(port);
1088 		return;
1089 	}
1090 
1091 	spin_lock_irqsave(&priv->lock, flags);
1092 	if (priv->rx_flags & THROTTLED) {
1093 		dev_dbg(dev, "%s - now throttling\n", __func__);
1094 		priv->rx_flags |= ACTUALLY_THROTTLED;
1095 		spin_unlock_irqrestore(&priv->lock, flags);
1096 		return;
1097 	}
1098 	spin_unlock_irqrestore(&priv->lock, flags);
1099 
1100 	tty = tty_port_tty_get(&port->port);
1101 	if (!tty) {
1102 		dev_dbg(dev, "%s - bad tty pointer - exiting\n", __func__);
1103 		return;
1104 	}
1105 
1106 	spin_lock_irqsave(&priv->lock, flags);
1107 	result = urb->actual_length;
1108 	switch (priv->pkt_fmt) {
1109 	default:
1110 	case packet_format_1:
1111 		/* This is for the CY7C64013... */
1112 		priv->current_status = data[0] & 0xF8;
1113 		bytes = data[1] + 2;
1114 		i = 2;
1115 		break;
1116 	case packet_format_2:
1117 		/* This is for the CY7C63743... */
1118 		priv->current_status = data[0] & 0xF8;
1119 		bytes = (data[0] & 0x07) + 1;
1120 		i = 1;
1121 		break;
1122 	}
1123 	spin_unlock_irqrestore(&priv->lock, flags);
1124 	if (result < bytes) {
1125 		dev_dbg(dev,
1126 			"%s - wrong packet size - received %d bytes but packet said %d bytes\n",
1127 			__func__, result, bytes);
1128 		goto continue_read;
1129 	}
1130 
1131 	usb_serial_debug_data(&port->dev, __func__, urb->actual_length, data);
1132 
1133 	spin_lock_irqsave(&priv->lock, flags);
1134 	/* check to see if status has changed */
1135 	if (priv->current_status != priv->prev_status) {
1136 		u8 delta = priv->current_status ^ priv->prev_status;
1137 
1138 		if (delta & UART_MSR_MASK) {
1139 			if (delta & UART_CTS)
1140 				port->icount.cts++;
1141 			if (delta & UART_DSR)
1142 				port->icount.dsr++;
1143 			if (delta & UART_RI)
1144 				port->icount.rng++;
1145 			if (delta & UART_CD)
1146 				port->icount.dcd++;
1147 
1148 			wake_up_interruptible(&port->port.delta_msr_wait);
1149 		}
1150 
1151 		priv->prev_status = priv->current_status;
1152 	}
1153 	spin_unlock_irqrestore(&priv->lock, flags);
1154 
1155 	/* hangup, as defined in acm.c... this might be a bad place for it
1156 	 * though */
1157 	if (tty && !C_CLOCAL(tty) && !(priv->current_status & UART_CD)) {
1158 		dev_dbg(dev, "%s - calling hangup\n", __func__);
1159 		tty_hangup(tty);
1160 		goto continue_read;
1161 	}
1162 
1163 	/* There is one error bit... I'm assuming it is a parity error
1164 	 * indicator as the generic firmware will set this bit to 1 if a
1165 	 * parity error occurs.
1166 	 * I can not find reference to any other error events. */
1167 	spin_lock_irqsave(&priv->lock, flags);
1168 	if (priv->current_status & CYP_ERROR) {
1169 		spin_unlock_irqrestore(&priv->lock, flags);
1170 		tty_flag = TTY_PARITY;
1171 		dev_dbg(dev, "%s - Parity Error detected\n", __func__);
1172 	} else
1173 		spin_unlock_irqrestore(&priv->lock, flags);
1174 
1175 	/* process read if there is data other than line status */
1176 	if (bytes > i) {
1177 		tty_insert_flip_string_fixed_flag(&port->port, data + i,
1178 				tty_flag, bytes - i);
1179 		tty_flip_buffer_push(&port->port);
1180 	}
1181 
1182 	spin_lock_irqsave(&priv->lock, flags);
1183 	/* control and status byte(s) are also counted */
1184 	priv->bytes_in += bytes;
1185 	spin_unlock_irqrestore(&priv->lock, flags);
1186 
1187 continue_read:
1188 	tty_kref_put(tty);
1189 
1190 	/* Continue trying to always read */
1191 
1192 	if (priv->comm_is_ok) {
1193 		usb_fill_int_urb(port->interrupt_in_urb, port->serial->dev,
1194 				usb_rcvintpipe(port->serial->dev,
1195 					port->interrupt_in_endpointAddress),
1196 				port->interrupt_in_urb->transfer_buffer,
1197 				port->interrupt_in_urb->transfer_buffer_length,
1198 				cypress_read_int_callback, port,
1199 				priv->read_urb_interval);
1200 		result = usb_submit_urb(port->interrupt_in_urb, GFP_ATOMIC);
1201 		if (result && result != -EPERM) {
1202 			dev_err(dev, "%s - failed resubmitting read urb, error %d\n",
1203 				__func__, result);
1204 			cypress_set_dead(port);
1205 		}
1206 	}
1207 } /* cypress_read_int_callback */
1208 
1209 
1210 static void cypress_write_int_callback(struct urb *urb)
1211 {
1212 	struct usb_serial_port *port = urb->context;
1213 	struct cypress_private *priv = usb_get_serial_port_data(port);
1214 	struct device *dev = &urb->dev->dev;
1215 	int status = urb->status;
1216 
1217 	switch (status) {
1218 	case 0:
1219 		/* success */
1220 		break;
1221 	case -ECONNRESET:
1222 	case -ENOENT:
1223 	case -ESHUTDOWN:
1224 		/* this urb is terminated, clean up */
1225 		dev_dbg(dev, "%s - urb shutting down with status: %d\n",
1226 			__func__, status);
1227 		priv->write_urb_in_use = 0;
1228 		return;
1229 	case -EPIPE:
1230 		/* Cannot call usb_clear_halt while in_interrupt */
1231 		/* FALLTHROUGH */
1232 	default:
1233 		dev_err(dev, "%s - unexpected nonzero write status received: %d\n",
1234 			__func__, status);
1235 		cypress_set_dead(port);
1236 		break;
1237 	}
1238 	priv->write_urb_in_use = 0;
1239 
1240 	/* send any buffered data */
1241 	cypress_send(port);
1242 }
1243 
1244 module_usb_serial_driver(serial_drivers, id_table_combined);
1245 
1246 MODULE_AUTHOR(DRIVER_AUTHOR);
1247 MODULE_DESCRIPTION(DRIVER_DESC);
1248 MODULE_LICENSE("GPL");
1249 
1250 module_param(stats, bool, S_IRUGO | S_IWUSR);
1251 MODULE_PARM_DESC(stats, "Enable statistics or not");
1252 module_param(interval, int, S_IRUGO | S_IWUSR);
1253 MODULE_PARM_DESC(interval, "Overrides interrupt interval");
1254 module_param(unstable_bauds, bool, S_IRUGO | S_IWUSR);
1255 MODULE_PARM_DESC(unstable_bauds, "Allow unstable baud rates");
1256