xref: /linux/drivers/usb/serial/cypress_m8.c (revision 7b4456767fd478ff1dbee55444d5e3e5a7194089)
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.rst 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_flip.h>
29 #include <linux/module.h>
30 #include <linux/moduleparam.h>
31 #include <linux/spinlock.h>
32 #include <linux/usb.h>
33 #include <linux/usb/serial.h>
34 #include <linux/serial.h>
35 #include <linux/kfifo.h>
36 #include <linux/delay.h>
37 #include <linux/unaligned.h>
38 
39 #include "cypress_m8.h"
40 
41 
42 static bool stats;
43 static int interval;
44 static bool unstable_bauds;
45 
46 #define DRIVER_AUTHOR "Lonnie Mendez <dignome@gmail.com>, Neil Whelchel <koyama@firstlight.net>"
47 #define DRIVER_DESC "Cypress USB to Serial Driver"
48 
49 /* write buffer size defines */
50 #define CYPRESS_BUF_SIZE	1024
51 
52 static const struct usb_device_id id_table_earthmate[] = {
53 	{ USB_DEVICE(VENDOR_ID_DELORME, PRODUCT_ID_EARTHMATEUSB) },
54 	{ USB_DEVICE(VENDOR_ID_DELORME, PRODUCT_ID_EARTHMATEUSB_LT20) },
55 	{ }						/* Terminating entry */
56 };
57 
58 static const struct usb_device_id id_table_cyphidcomrs232[] = {
59 	{ USB_DEVICE(VENDOR_ID_CYPRESS, PRODUCT_ID_CYPHIDCOM) },
60 	{ USB_DEVICE(VENDOR_ID_SAI, PRODUCT_ID_CYPHIDCOM) },
61 	{ USB_DEVICE(VENDOR_ID_POWERCOM, PRODUCT_ID_UPS) },
62 	{ USB_DEVICE(VENDOR_ID_FRWD, PRODUCT_ID_CYPHIDCOM_FRWD) },
63 	{ }						/* Terminating entry */
64 };
65 
66 static const struct usb_device_id id_table_nokiaca42v2[] = {
67 	{ USB_DEVICE(VENDOR_ID_DAZZLE, PRODUCT_ID_CA42) },
68 	{ }						/* Terminating entry */
69 };
70 
71 static const struct usb_device_id id_table_combined[] = {
72 	{ USB_DEVICE(VENDOR_ID_DELORME, PRODUCT_ID_EARTHMATEUSB) },
73 	{ USB_DEVICE(VENDOR_ID_DELORME, PRODUCT_ID_EARTHMATEUSB_LT20) },
74 	{ USB_DEVICE(VENDOR_ID_CYPRESS, PRODUCT_ID_CYPHIDCOM) },
75 	{ USB_DEVICE(VENDOR_ID_SAI, 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 	__u8 line_control;	   	   /* holds dtr / rts value */
102 	__u8 current_status;	   	   /* received from last read - info on dsr,cts,cd,ri,etc */
103 	__u8 current_config;	   	   /* stores the current configuration byte */
104 	__u8 rx_flags;			   /* throttling - used from whiteheat/ftdi_sio */
105 	enum packet_format pkt_fmt;	   /* format to use for packet send / receive */
106 	int get_cfg_unsafe;		   /* If true, the CYPRESS_GET_CONFIG is unsafe */
107 	int baud_rate;			   /* stores current baud rate in
108 					      integer form */
109 	char prev_status;		   /* used for TIOCMIWAIT */
110 };
111 
112 /* function prototypes for the Cypress USB to serial device */
113 static int  cypress_earthmate_port_probe(struct usb_serial_port *port);
114 static int  cypress_hidcom_port_probe(struct usb_serial_port *port);
115 static int  cypress_ca42v2_port_probe(struct usb_serial_port *port);
116 static void cypress_port_remove(struct usb_serial_port *port);
117 static int  cypress_open(struct tty_struct *tty, struct usb_serial_port *port);
118 static void cypress_close(struct usb_serial_port *port);
119 static void cypress_dtr_rts(struct usb_serial_port *port, int on);
120 static int  cypress_write(struct tty_struct *tty, struct usb_serial_port *port,
121 			const unsigned char *buf, int count);
122 static void cypress_send(struct usb_serial_port *port);
123 static unsigned int cypress_write_room(struct tty_struct *tty);
124 static void cypress_earthmate_init_termios(struct tty_struct *tty);
125 static void cypress_set_termios(struct tty_struct *tty,
126 				struct usb_serial_port *port,
127 				const struct ktermios *old_termios);
128 static int  cypress_tiocmget(struct tty_struct *tty);
129 static int  cypress_tiocmset(struct tty_struct *tty,
130 			unsigned int set, unsigned int clear);
131 static unsigned int cypress_chars_in_buffer(struct tty_struct *tty);
132 static void cypress_throttle(struct tty_struct *tty);
133 static void cypress_unthrottle(struct tty_struct *tty);
134 static void cypress_set_dead(struct usb_serial_port *port);
135 static void cypress_read_int_callback(struct urb *urb);
136 static void cypress_write_int_callback(struct urb *urb);
137 
138 static struct usb_serial_driver cypress_earthmate_device = {
139 	.driver = {
140 		.name =			"earthmate",
141 	},
142 	.description =			"DeLorme Earthmate USB",
143 	.id_table =			id_table_earthmate,
144 	.num_ports =			1,
145 	.port_probe =			cypress_earthmate_port_probe,
146 	.port_remove =			cypress_port_remove,
147 	.open =				cypress_open,
148 	.close =			cypress_close,
149 	.dtr_rts =			cypress_dtr_rts,
150 	.write =			cypress_write,
151 	.write_room =			cypress_write_room,
152 	.init_termios =			cypress_earthmate_init_termios,
153 	.set_termios =			cypress_set_termios,
154 	.tiocmget =			cypress_tiocmget,
155 	.tiocmset =			cypress_tiocmset,
156 	.tiocmiwait =			usb_serial_generic_tiocmiwait,
157 	.chars_in_buffer =		cypress_chars_in_buffer,
158 	.throttle =		 	cypress_throttle,
159 	.unthrottle =			cypress_unthrottle,
160 	.read_int_callback =		cypress_read_int_callback,
161 	.write_int_callback =		cypress_write_int_callback,
162 };
163 
164 static struct usb_serial_driver cypress_hidcom_device = {
165 	.driver = {
166 		.name =			"cyphidcom",
167 	},
168 	.description =			"HID->COM RS232 Adapter",
169 	.id_table =			id_table_cyphidcomrs232,
170 	.num_ports =			1,
171 	.port_probe =			cypress_hidcom_port_probe,
172 	.port_remove =			cypress_port_remove,
173 	.open =				cypress_open,
174 	.close =			cypress_close,
175 	.dtr_rts =			cypress_dtr_rts,
176 	.write =			cypress_write,
177 	.write_room =			cypress_write_room,
178 	.set_termios =			cypress_set_termios,
179 	.tiocmget =			cypress_tiocmget,
180 	.tiocmset =			cypress_tiocmset,
181 	.tiocmiwait =			usb_serial_generic_tiocmiwait,
182 	.chars_in_buffer =		cypress_chars_in_buffer,
183 	.throttle =			cypress_throttle,
184 	.unthrottle =			cypress_unthrottle,
185 	.read_int_callback =		cypress_read_int_callback,
186 	.write_int_callback =		cypress_write_int_callback,
187 };
188 
189 static struct usb_serial_driver cypress_ca42v2_device = {
190 	.driver = {
191 		.name =			"nokiaca42v2",
192 	},
193 	.description =			"Nokia CA-42 V2 Adapter",
194 	.id_table =			id_table_nokiaca42v2,
195 	.num_ports =			1,
196 	.port_probe =			cypress_ca42v2_port_probe,
197 	.port_remove =			cypress_port_remove,
198 	.open =				cypress_open,
199 	.close =			cypress_close,
200 	.dtr_rts =			cypress_dtr_rts,
201 	.write =			cypress_write,
202 	.write_room =			cypress_write_room,
203 	.set_termios =			cypress_set_termios,
204 	.tiocmget =			cypress_tiocmget,
205 	.tiocmset =			cypress_tiocmset,
206 	.tiocmiwait =			usb_serial_generic_tiocmiwait,
207 	.chars_in_buffer =		cypress_chars_in_buffer,
208 	.throttle =			cypress_throttle,
209 	.unthrottle =			cypress_unthrottle,
210 	.read_int_callback =		cypress_read_int_callback,
211 	.write_int_callback =		cypress_write_int_callback,
212 };
213 
214 static struct usb_serial_driver * const serial_drivers[] = {
215 	&cypress_earthmate_device, &cypress_hidcom_device,
216 	&cypress_ca42v2_device, NULL
217 };
218 
219 /*****************************************************************************
220  * Cypress serial helper functions
221  *****************************************************************************/
222 
223 /* FRWD Dongle hidcom needs to skip reset and speed checks */
224 static inline bool is_frwd(struct usb_device *dev)
225 {
226 	return ((le16_to_cpu(dev->descriptor.idVendor) == VENDOR_ID_FRWD) &&
227 		(le16_to_cpu(dev->descriptor.idProduct) == PRODUCT_ID_CYPHIDCOM_FRWD));
228 }
229 
230 static int analyze_baud_rate(struct usb_serial_port *port, speed_t new_rate)
231 {
232 	struct cypress_private *priv;
233 	priv = usb_get_serial_port_data(port);
234 
235 	if (unstable_bauds)
236 		return new_rate;
237 
238 	/* FRWD Dongle uses 115200 bps */
239 	if (is_frwd(port->serial->dev))
240 		return new_rate;
241 
242 	/*
243 	 * The general purpose firmware for the Cypress M8 allows for
244 	 * a maximum speed of 57600bps (I have no idea whether DeLorme
245 	 * chose to use the general purpose firmware or not), if you
246 	 * need to modify this speed setting for your own project
247 	 * please add your own chiptype and modify the code likewise.
248 	 * The Cypress HID->COM device will work successfully up to
249 	 * 115200bps (but the actual throughput is around 3kBps).
250 	 */
251 	if (port->serial->dev->speed == USB_SPEED_LOW) {
252 		/*
253 		 * Mike Isely <isely@pobox.com> 2-Feb-2008: The
254 		 * Cypress app note that describes this mechanism
255 		 * states that the low-speed part can't handle more
256 		 * than 800 bytes/sec, in which case 4800 baud is the
257 		 * safest speed for a part like that.
258 		 */
259 		if (new_rate > 4800) {
260 			dev_dbg(&port->dev,
261 				"%s - failed setting baud rate, device incapable speed %d\n",
262 				__func__, new_rate);
263 			return -1;
264 		}
265 	}
266 	switch (priv->chiptype) {
267 	case CT_EARTHMATE:
268 		if (new_rate <= 600) {
269 			/* 300 and 600 baud rates are supported under
270 			 * the generic firmware, but are not used with
271 			 * NMEA and SiRF protocols */
272 			dev_dbg(&port->dev,
273 				"%s - failed setting baud rate, unsupported speed of %d on Earthmate GPS\n",
274 				__func__, new_rate);
275 			return -1;
276 		}
277 		break;
278 	default:
279 		break;
280 	}
281 	return new_rate;
282 }
283 
284 
285 /* This function can either set or retrieve the current serial line settings */
286 static int cypress_serial_control(struct tty_struct *tty,
287 	struct usb_serial_port *port, speed_t baud_rate, int data_bits,
288 	int stop_bits, int parity_enable, int parity_type, int reset,
289 	int cypress_request_type)
290 {
291 	int new_baudrate = 0, retval = 0, tries = 0;
292 	struct cypress_private *priv;
293 	struct device *dev = &port->dev;
294 	u8 *feature_buffer;
295 	const unsigned int feature_len = 5;
296 	unsigned long flags;
297 
298 	priv = usb_get_serial_port_data(port);
299 
300 	if (!priv->comm_is_ok)
301 		return -ENODEV;
302 
303 	feature_buffer = kcalloc(feature_len, sizeof(u8), GFP_KERNEL);
304 	if (!feature_buffer)
305 		return -ENOMEM;
306 
307 	switch (cypress_request_type) {
308 	case CYPRESS_SET_CONFIG:
309 		/* 0 means 'Hang up' so doesn't change the true bit rate */
310 		new_baudrate = priv->baud_rate;
311 		if (baud_rate && baud_rate != priv->baud_rate) {
312 			dev_dbg(dev, "%s - baud rate is changing\n", __func__);
313 			retval = analyze_baud_rate(port, baud_rate);
314 			if (retval >= 0) {
315 				new_baudrate = retval;
316 				dev_dbg(dev, "%s - New baud rate set to %d\n",
317 					__func__, new_baudrate);
318 			}
319 		}
320 		dev_dbg(dev, "%s - baud rate is being sent as %d\n", __func__,
321 			new_baudrate);
322 
323 		/* fill the feature_buffer with new configuration */
324 		put_unaligned_le32(new_baudrate, feature_buffer);
325 		feature_buffer[4] |= data_bits - 5;   /* assign data bits in 2 bit space ( max 3 ) */
326 		/* 1 bit gap */
327 		feature_buffer[4] |= (stop_bits << 3);   /* assign stop bits in 1 bit space */
328 		feature_buffer[4] |= (parity_enable << 4);   /* assign parity flag in 1 bit space */
329 		feature_buffer[4] |= (parity_type << 5);   /* assign parity type in 1 bit space */
330 		/* 1 bit gap */
331 		feature_buffer[4] |= (reset << 7);   /* assign reset at end of byte, 1 bit space */
332 
333 		dev_dbg(dev, "%s - device is being sent this feature report:\n", __func__);
334 		dev_dbg(dev, "%s - %02X - %02X - %02X - %02X - %02X\n", __func__,
335 			feature_buffer[0], feature_buffer[1],
336 			feature_buffer[2], feature_buffer[3],
337 			feature_buffer[4]);
338 
339 		do {
340 			retval = usb_control_msg(port->serial->dev,
341 					usb_sndctrlpipe(port->serial->dev, 0),
342 					HID_REQ_SET_REPORT,
343 					USB_DIR_OUT | USB_RECIP_INTERFACE | USB_TYPE_CLASS,
344 					0x0300, 0, feature_buffer,
345 					feature_len, 500);
346 
347 			if (tries++ >= 3)
348 				break;
349 
350 		} while (retval != feature_len &&
351 			 retval != -ENODEV);
352 
353 		if (retval != feature_len) {
354 			dev_err(dev, "%s - failed sending serial line settings - %d\n",
355 				__func__, retval);
356 			cypress_set_dead(port);
357 		} else {
358 			spin_lock_irqsave(&priv->lock, flags);
359 			priv->baud_rate = new_baudrate;
360 			priv->current_config = feature_buffer[4];
361 			spin_unlock_irqrestore(&priv->lock, flags);
362 			/* If we asked for a speed change encode it */
363 			if (baud_rate)
364 				tty_encode_baud_rate(tty,
365 					new_baudrate, new_baudrate);
366 		}
367 	break;
368 	case CYPRESS_GET_CONFIG:
369 		if (priv->get_cfg_unsafe) {
370 			/* Not implemented for this device,
371 			   and if we try to do it we're likely
372 			   to crash the hardware. */
373 			retval = -ENOTTY;
374 			goto out;
375 		}
376 		dev_dbg(dev, "%s - retrieving serial line settings\n", __func__);
377 		do {
378 			retval = usb_control_msg(port->serial->dev,
379 					usb_rcvctrlpipe(port->serial->dev, 0),
380 					HID_REQ_GET_REPORT,
381 					USB_DIR_IN | USB_RECIP_INTERFACE | USB_TYPE_CLASS,
382 					0x0300, 0, feature_buffer,
383 					feature_len, 500);
384 
385 			if (tries++ >= 3)
386 				break;
387 		} while (retval != feature_len
388 						&& retval != -ENODEV);
389 
390 		if (retval != feature_len) {
391 			dev_err(dev, "%s - failed to retrieve serial line settings - %d\n",
392 				__func__, retval);
393 			cypress_set_dead(port);
394 			goto out;
395 		} else {
396 			spin_lock_irqsave(&priv->lock, flags);
397 			/* store the config in one byte, and later
398 			   use bit masks to check values */
399 			priv->current_config = feature_buffer[4];
400 			priv->baud_rate = get_unaligned_le32(feature_buffer);
401 			spin_unlock_irqrestore(&priv->lock, flags);
402 		}
403 	}
404 	spin_lock_irqsave(&priv->lock, flags);
405 	++priv->cmd_count;
406 	spin_unlock_irqrestore(&priv->lock, flags);
407 out:
408 	kfree(feature_buffer);
409 	return retval;
410 } /* cypress_serial_control */
411 
412 
413 static void cypress_set_dead(struct usb_serial_port *port)
414 {
415 	struct cypress_private *priv = usb_get_serial_port_data(port);
416 	unsigned long flags;
417 
418 	spin_lock_irqsave(&priv->lock, flags);
419 	if (!priv->comm_is_ok) {
420 		spin_unlock_irqrestore(&priv->lock, flags);
421 		return;
422 	}
423 	priv->comm_is_ok = 0;
424 	spin_unlock_irqrestore(&priv->lock, flags);
425 
426 	dev_err(&port->dev, "cypress_m8 suspending failing port %d - "
427 		"interval might be too short\n", port->port_number);
428 }
429 
430 
431 /*****************************************************************************
432  * Cypress serial driver functions
433  *****************************************************************************/
434 
435 
436 static int cypress_generic_port_probe(struct usb_serial_port *port)
437 {
438 	struct usb_serial *serial = port->serial;
439 	struct cypress_private *priv;
440 
441 	if (!port->interrupt_out_urb || !port->interrupt_in_urb) {
442 		dev_err(&port->dev, "required endpoint is missing\n");
443 		return -ENODEV;
444 	}
445 
446 	/*
447 	 * The buffer must be large enough for the one or two-byte header (and
448 	 * following data), but assume anything smaller than eight bytes is
449 	 * broken.
450 	 */
451 	if (port->interrupt_out_size < 8)
452 		return -EINVAL;
453 
454 	priv = kzalloc_obj(struct cypress_private);
455 	if (!priv)
456 		return -ENOMEM;
457 
458 	priv->comm_is_ok = !0;
459 	spin_lock_init(&priv->lock);
460 	if (kfifo_alloc(&priv->write_fifo, CYPRESS_BUF_SIZE, GFP_KERNEL)) {
461 		kfree(priv);
462 		return -ENOMEM;
463 	}
464 
465 	/* Skip reset for FRWD device. It is a workaound:
466 	   device hangs if it receives SET_CONFIGURE in Configured
467 	   state. */
468 	if (!is_frwd(serial->dev))
469 		usb_reset_configuration(serial->dev);
470 
471 	priv->cmd_ctrl = 0;
472 	priv->line_control = 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 		dev_dbg(&port->dev, "%s - read & write intervals forced to %d\n",
489 			__func__, interval);
490 	} else {
491 		priv->write_urb_interval = port->interrupt_out_urb->interval;
492 		priv->read_urb_interval = port->interrupt_in_urb->interval;
493 		dev_dbg(&port->dev, "%s - intervals: read=%d write=%d\n",
494 			__func__, priv->read_urb_interval,
495 			priv->write_urb_interval);
496 	}
497 	usb_set_serial_port_data(port, priv);
498 
499 	port->port.drain_delay = 256;
500 
501 	return 0;
502 }
503 
504 
505 static int cypress_earthmate_port_probe(struct usb_serial_port *port)
506 {
507 	struct usb_serial *serial = port->serial;
508 	struct cypress_private *priv;
509 	int ret;
510 
511 	ret = cypress_generic_port_probe(port);
512 	if (ret) {
513 		dev_dbg(&port->dev, "%s - Failed setting up port\n", __func__);
514 		return ret;
515 	}
516 
517 	priv = usb_get_serial_port_data(port);
518 	priv->chiptype = CT_EARTHMATE;
519 	/* All Earthmate devices use the separated-count packet
520 	   format!  Idiotic. */
521 	priv->pkt_fmt = packet_format_1;
522 	if (serial->dev->descriptor.idProduct !=
523 				cpu_to_le16(PRODUCT_ID_EARTHMATEUSB)) {
524 		/* The old original USB Earthmate seemed able to
525 		   handle GET_CONFIG requests; everything they've
526 		   produced since that time crashes if this command is
527 		   attempted :-( */
528 		dev_dbg(&port->dev,
529 			"%s - Marking this device as unsafe for GET_CONFIG commands\n",
530 			__func__);
531 		priv->get_cfg_unsafe = !0;
532 	}
533 
534 	return 0;
535 }
536 
537 static int cypress_hidcom_port_probe(struct usb_serial_port *port)
538 {
539 	struct cypress_private *priv;
540 	int ret;
541 
542 	ret = cypress_generic_port_probe(port);
543 	if (ret) {
544 		dev_dbg(&port->dev, "%s - Failed setting up port\n", __func__);
545 		return ret;
546 	}
547 
548 	priv = usb_get_serial_port_data(port);
549 	priv->chiptype = CT_CYPHIDCOM;
550 
551 	return 0;
552 }
553 
554 static int cypress_ca42v2_port_probe(struct usb_serial_port *port)
555 {
556 	struct cypress_private *priv;
557 	int ret;
558 
559 	ret = cypress_generic_port_probe(port);
560 	if (ret) {
561 		dev_dbg(&port->dev, "%s - Failed setting up port\n", __func__);
562 		return ret;
563 	}
564 
565 	priv = usb_get_serial_port_data(port);
566 	priv->chiptype = CT_CA42V2;
567 
568 	return 0;
569 }
570 
571 static void cypress_port_remove(struct usb_serial_port *port)
572 {
573 	struct cypress_private *priv;
574 
575 	priv = usb_get_serial_port_data(port);
576 
577 	kfifo_free(&priv->write_fifo);
578 	kfree(priv);
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, NULL);
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 unsigned 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 	unsigned int room;
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 %u\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_earthmate_init_termios(struct tty_struct *tty)
861 {
862 	tty_encode_baud_rate(tty, 4800, 4800);
863 }
864 
865 static void cypress_set_termios(struct tty_struct *tty,
866 				struct usb_serial_port *port,
867 				const struct ktermios *old_termios)
868 {
869 	struct cypress_private *priv = usb_get_serial_port_data(port);
870 	struct device *dev = &port->dev;
871 	int data_bits, stop_bits, parity_type, parity_enable;
872 	unsigned int cflag;
873 	unsigned long flags;
874 	__u8 oldlines;
875 	int linechange = 0;
876 
877 	/* Unsupported features need clearing */
878 	tty->termios.c_cflag &= ~(CMSPAR|CRTSCTS);
879 
880 	cflag = tty->termios.c_cflag;
881 
882 	/* set number of data bits, parity, stop bits */
883 	/* when parity is disabled the parity type bit is ignored */
884 
885 	/* 1 means 2 stop bits, 0 means 1 stop bit */
886 	stop_bits = cflag & CSTOPB ? 1 : 0;
887 
888 	if (cflag & PARENB) {
889 		parity_enable = 1;
890 		/* 1 means odd parity, 0 means even parity */
891 		parity_type = cflag & PARODD ? 1 : 0;
892 	} else
893 		parity_enable = parity_type = 0;
894 
895 	data_bits = tty_get_char_size(cflag);
896 
897 	spin_lock_irqsave(&priv->lock, flags);
898 	oldlines = priv->line_control;
899 	if ((cflag & CBAUD) == B0) {
900 		/* drop dtr and rts */
901 		dev_dbg(dev, "%s - dropping the lines, baud rate 0bps\n", __func__);
902 		priv->line_control &= ~(CONTROL_DTR | CONTROL_RTS);
903 	} else
904 		priv->line_control = (CONTROL_DTR | CONTROL_RTS);
905 	spin_unlock_irqrestore(&priv->lock, flags);
906 
907 	dev_dbg(dev, "%s - sending %d stop_bits, %d parity_enable, %d parity_type, %d data_bits (+5)\n",
908 		__func__, stop_bits, parity_enable, parity_type, data_bits);
909 
910 	cypress_serial_control(tty, port, tty_get_baud_rate(tty),
911 			data_bits, stop_bits,
912 			parity_enable, parity_type,
913 			0, CYPRESS_SET_CONFIG);
914 
915 	/* we perform a CYPRESS_GET_CONFIG so that the current settings are
916 	 * filled into the private structure this should confirm that all is
917 	 * working if it returns what we just set */
918 	cypress_serial_control(tty, port, 0, 0, 0, 0, 0, 0, CYPRESS_GET_CONFIG);
919 
920 	/* Here we can define custom tty settings for devices; the main tty
921 	 * termios flag base comes from empeg.c */
922 
923 	spin_lock_irqsave(&priv->lock, flags);
924 	if (priv->chiptype == CT_EARTHMATE && priv->baud_rate == 4800) {
925 		dev_dbg(dev, "Using custom termios settings for a baud rate of 4800bps.\n");
926 		/* define custom termios settings for NMEA protocol */
927 
928 		tty->termios.c_iflag /* input modes - */
929 			&= ~(IGNBRK  /* disable ignore break */
930 			| BRKINT     /* disable break causes interrupt */
931 			| PARMRK     /* disable mark parity errors */
932 			| ISTRIP     /* disable clear high bit of input char */
933 			| INLCR      /* disable translate NL to CR */
934 			| IGNCR      /* disable ignore CR */
935 			| ICRNL      /* disable translate CR to NL */
936 			| IXON);     /* disable enable XON/XOFF flow control */
937 
938 		tty->termios.c_oflag /* output modes */
939 			&= ~OPOST;    /* disable postprocess output char */
940 
941 		tty->termios.c_lflag /* line discipline modes */
942 			&= ~(ECHO     /* disable echo input characters */
943 			| ECHONL      /* disable echo new line */
944 			| ICANON      /* disable erase, kill, werase, and rprnt
945 					 special characters */
946 			| ISIG        /* disable interrupt, quit, and suspend
947 					 special characters */
948 			| IEXTEN);    /* disable non-POSIX special characters */
949 	} /* CT_CYPHIDCOM: Application should handle this for device */
950 
951 	linechange = (priv->line_control != oldlines);
952 	spin_unlock_irqrestore(&priv->lock, flags);
953 
954 	/* if necessary, set lines */
955 	if (linechange) {
956 		priv->cmd_ctrl = 1;
957 		cypress_write(tty, port, NULL, 0);
958 	}
959 } /* cypress_set_termios */
960 
961 
962 /* returns amount of data still left in soft buffer */
963 static unsigned int cypress_chars_in_buffer(struct tty_struct *tty)
964 {
965 	struct usb_serial_port *port = tty->driver_data;
966 	struct cypress_private *priv = usb_get_serial_port_data(port);
967 	unsigned int chars;
968 	unsigned long flags;
969 
970 	spin_lock_irqsave(&priv->lock, flags);
971 	chars = kfifo_len(&priv->write_fifo);
972 	spin_unlock_irqrestore(&priv->lock, flags);
973 
974 	dev_dbg(&port->dev, "%s - returns %u\n", __func__, chars);
975 	return chars;
976 }
977 
978 
979 static void cypress_throttle(struct tty_struct *tty)
980 {
981 	struct usb_serial_port *port = tty->driver_data;
982 	struct cypress_private *priv = usb_get_serial_port_data(port);
983 
984 	spin_lock_irq(&priv->lock);
985 	priv->rx_flags = THROTTLED;
986 	spin_unlock_irq(&priv->lock);
987 }
988 
989 
990 static void cypress_unthrottle(struct tty_struct *tty)
991 {
992 	struct usb_serial_port *port = tty->driver_data;
993 	struct cypress_private *priv = usb_get_serial_port_data(port);
994 	int actually_throttled, result;
995 
996 	spin_lock_irq(&priv->lock);
997 	actually_throttled = priv->rx_flags & ACTUALLY_THROTTLED;
998 	priv->rx_flags = 0;
999 	spin_unlock_irq(&priv->lock);
1000 
1001 	if (!priv->comm_is_ok)
1002 		return;
1003 
1004 	if (actually_throttled) {
1005 		result = usb_submit_urb(port->interrupt_in_urb, GFP_KERNEL);
1006 		if (result) {
1007 			dev_err(&port->dev, "%s - failed submitting read urb, "
1008 					"error %d\n", __func__, result);
1009 			cypress_set_dead(port);
1010 		}
1011 	}
1012 }
1013 
1014 
1015 static void cypress_read_int_callback(struct urb *urb)
1016 {
1017 	struct usb_serial_port *port = urb->context;
1018 	struct cypress_private *priv = usb_get_serial_port_data(port);
1019 	struct device *dev = &urb->dev->dev;
1020 	struct tty_struct *tty;
1021 	unsigned char *data = urb->transfer_buffer;
1022 	unsigned long flags;
1023 	char tty_flag = TTY_NORMAL;
1024 	int bytes = 0;
1025 	int result;
1026 	int status = urb->status;
1027 	int i;
1028 
1029 	switch (status) {
1030 	case 0: /* success */
1031 		break;
1032 	case -ECONNRESET:
1033 	case -ENOENT:
1034 	case -ESHUTDOWN:
1035 		/* precursor to disconnect so just go away */
1036 		return;
1037 	case -EPIPE:
1038 		/* Can't call usb_clear_halt while in_interrupt */
1039 		fallthrough;
1040 	default:
1041 		/* something ugly is going on... */
1042 		dev_err(dev, "%s - unexpected nonzero read status received: %d\n",
1043 			__func__, status);
1044 		cypress_set_dead(port);
1045 		return;
1046 	}
1047 
1048 	spin_lock_irqsave(&priv->lock, flags);
1049 	if (priv->rx_flags & THROTTLED) {
1050 		dev_dbg(dev, "%s - now throttling\n", __func__);
1051 		priv->rx_flags |= ACTUALLY_THROTTLED;
1052 		spin_unlock_irqrestore(&priv->lock, flags);
1053 		return;
1054 	}
1055 	spin_unlock_irqrestore(&priv->lock, flags);
1056 
1057 	tty = tty_port_tty_get(&port->port);
1058 	if (!tty) {
1059 		dev_dbg(dev, "%s - bad tty pointer - exiting\n", __func__);
1060 		return;
1061 	}
1062 
1063 	spin_lock_irqsave(&priv->lock, flags);
1064 	result = urb->actual_length;
1065 	i = 0;
1066 	switch (priv->pkt_fmt) {
1067 	default:
1068 	case packet_format_1:
1069 		/* This is for the CY7C64013... */
1070 		if (result < 2)
1071 			break;
1072 		priv->current_status = data[0] & 0xF8;
1073 		bytes = data[1] + 2;
1074 		i = 2;
1075 		break;
1076 	case packet_format_2:
1077 		/* This is for the CY7C63743... */
1078 		if (result < 1)
1079 			break;
1080 		priv->current_status = data[0] & 0xF8;
1081 		bytes = (data[0] & 0x07) + 1;
1082 		i = 1;
1083 		break;
1084 	}
1085 	spin_unlock_irqrestore(&priv->lock, flags);
1086 	if (i == 0) {
1087 		dev_dbg(dev, "%s - short packet received: %d bytes\n",
1088 			__func__, result);
1089 		goto continue_read;
1090 	}
1091 	if (result < bytes) {
1092 		dev_dbg(dev,
1093 			"%s - wrong packet size - received %d bytes but packet said %d bytes\n",
1094 			__func__, result, bytes);
1095 		goto continue_read;
1096 	}
1097 
1098 	usb_serial_debug_data(&port->dev, __func__, urb->actual_length, data);
1099 
1100 	spin_lock_irqsave(&priv->lock, flags);
1101 	/* check to see if status has changed */
1102 	if (priv->current_status != priv->prev_status) {
1103 		u8 delta = priv->current_status ^ priv->prev_status;
1104 
1105 		if (delta & UART_MSR_MASK) {
1106 			if (delta & UART_CTS)
1107 				port->icount.cts++;
1108 			if (delta & UART_DSR)
1109 				port->icount.dsr++;
1110 			if (delta & UART_RI)
1111 				port->icount.rng++;
1112 			if (delta & UART_CD)
1113 				port->icount.dcd++;
1114 
1115 			wake_up_interruptible(&port->port.delta_msr_wait);
1116 		}
1117 
1118 		priv->prev_status = priv->current_status;
1119 	}
1120 	spin_unlock_irqrestore(&priv->lock, flags);
1121 
1122 	/* hangup, as defined in acm.c... this might be a bad place for it
1123 	 * though */
1124 	if (tty && !C_CLOCAL(tty) && !(priv->current_status & UART_CD)) {
1125 		dev_dbg(dev, "%s - calling hangup\n", __func__);
1126 		tty_hangup(tty);
1127 		goto continue_read;
1128 	}
1129 
1130 	/* There is one error bit... I'm assuming it is a parity error
1131 	 * indicator as the generic firmware will set this bit to 1 if a
1132 	 * parity error occurs.
1133 	 * I can not find reference to any other error events. */
1134 	spin_lock_irqsave(&priv->lock, flags);
1135 	if (priv->current_status & CYP_ERROR) {
1136 		spin_unlock_irqrestore(&priv->lock, flags);
1137 		tty_flag = TTY_PARITY;
1138 		dev_dbg(dev, "%s - Parity Error detected\n", __func__);
1139 	} else
1140 		spin_unlock_irqrestore(&priv->lock, flags);
1141 
1142 	/* process read if there is data other than line status */
1143 	if (bytes > i) {
1144 		tty_insert_flip_string_fixed_flag(&port->port, data + i,
1145 				tty_flag, bytes - i);
1146 		tty_flip_buffer_push(&port->port);
1147 	}
1148 
1149 	spin_lock_irqsave(&priv->lock, flags);
1150 	/* control and status byte(s) are also counted */
1151 	priv->bytes_in += bytes;
1152 	spin_unlock_irqrestore(&priv->lock, flags);
1153 
1154 continue_read:
1155 	tty_kref_put(tty);
1156 
1157 	/* Continue trying to always read */
1158 
1159 	if (priv->comm_is_ok) {
1160 		usb_fill_int_urb(port->interrupt_in_urb, port->serial->dev,
1161 				usb_rcvintpipe(port->serial->dev,
1162 					port->interrupt_in_endpointAddress),
1163 				port->interrupt_in_urb->transfer_buffer,
1164 				port->interrupt_in_urb->transfer_buffer_length,
1165 				cypress_read_int_callback, port,
1166 				priv->read_urb_interval);
1167 		result = usb_submit_urb(port->interrupt_in_urb, GFP_ATOMIC);
1168 		if (result && result != -EPERM) {
1169 			dev_err(dev, "%s - failed resubmitting read urb, error %d\n",
1170 				__func__, result);
1171 			cypress_set_dead(port);
1172 		}
1173 	}
1174 } /* cypress_read_int_callback */
1175 
1176 
1177 static void cypress_write_int_callback(struct urb *urb)
1178 {
1179 	struct usb_serial_port *port = urb->context;
1180 	struct cypress_private *priv = usb_get_serial_port_data(port);
1181 	struct device *dev = &urb->dev->dev;
1182 	int status = urb->status;
1183 
1184 	switch (status) {
1185 	case 0:
1186 		/* success */
1187 		break;
1188 	case -ECONNRESET:
1189 	case -ENOENT:
1190 	case -ESHUTDOWN:
1191 		/* this urb is terminated, clean up */
1192 		dev_dbg(dev, "%s - urb shutting down with status: %d\n",
1193 			__func__, status);
1194 		priv->write_urb_in_use = 0;
1195 		return;
1196 	case -EPIPE:
1197 		/* Cannot call usb_clear_halt while in_interrupt */
1198 		fallthrough;
1199 	default:
1200 		dev_err(dev, "%s - unexpected nonzero write status received: %d\n",
1201 			__func__, status);
1202 		cypress_set_dead(port);
1203 		break;
1204 	}
1205 	priv->write_urb_in_use = 0;
1206 
1207 	/* send any buffered data */
1208 	cypress_send(port);
1209 }
1210 
1211 module_usb_serial_driver(serial_drivers, id_table_combined);
1212 
1213 MODULE_AUTHOR(DRIVER_AUTHOR);
1214 MODULE_DESCRIPTION(DRIVER_DESC);
1215 MODULE_LICENSE("GPL");
1216 
1217 module_param(stats, bool, 0644);
1218 MODULE_PARM_DESC(stats, "Enable statistics or not");
1219 module_param(interval, int, 0644);
1220 MODULE_PARM_DESC(interval, "Overrides interrupt interval");
1221 module_param(unstable_bauds, bool, 0644);
1222 MODULE_PARM_DESC(unstable_bauds, "Allow unstable baud rates");
1223