xref: /linux/drivers/usb/serial/cypress_m8.c (revision 06a130e42a5bfc84795464bff023bff4c16f58c5)
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_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 <linux/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_SAI, PRODUCT_ID_CYPHIDCOM) },
63 	{ USB_DEVICE(VENDOR_ID_POWERCOM, PRODUCT_ID_UPS) },
64 	{ USB_DEVICE(VENDOR_ID_FRWD, PRODUCT_ID_CYPHIDCOM_FRWD) },
65 	{ }						/* Terminating entry */
66 };
67 
68 static const struct usb_device_id id_table_nokiaca42v2[] = {
69 	{ USB_DEVICE(VENDOR_ID_DAZZLE, PRODUCT_ID_CA42) },
70 	{ }						/* Terminating entry */
71 };
72 
73 static const struct usb_device_id id_table_combined[] = {
74 	{ USB_DEVICE(VENDOR_ID_DELORME, PRODUCT_ID_EARTHMATEUSB) },
75 	{ USB_DEVICE(VENDOR_ID_DELORME, PRODUCT_ID_EARTHMATEUSB_LT20) },
76 	{ USB_DEVICE(VENDOR_ID_CYPRESS, PRODUCT_ID_CYPHIDCOM) },
77 	{ USB_DEVICE(VENDOR_ID_SAI, PRODUCT_ID_CYPHIDCOM) },
78 	{ USB_DEVICE(VENDOR_ID_POWERCOM, PRODUCT_ID_UPS) },
79 	{ USB_DEVICE(VENDOR_ID_FRWD, PRODUCT_ID_CYPHIDCOM_FRWD) },
80 	{ USB_DEVICE(VENDOR_ID_DAZZLE, PRODUCT_ID_CA42) },
81 	{ }						/* Terminating entry */
82 };
83 
84 MODULE_DEVICE_TABLE(usb, id_table_combined);
85 
86 enum packet_format {
87 	packet_format_1,  /* b0:status, b1:payload count */
88 	packet_format_2   /* b0[7:3]:status, b0[2:0]:payload count */
89 };
90 
91 struct cypress_private {
92 	spinlock_t lock;		   /* private lock */
93 	int chiptype;			   /* identifier of device, for quirks/etc */
94 	int bytes_in;			   /* used for statistics */
95 	int bytes_out;			   /* used for statistics */
96 	int cmd_count;			   /* used for statistics */
97 	int cmd_ctrl;			   /* always set this to 1 before issuing a command */
98 	struct kfifo write_fifo;	   /* write fifo */
99 	int write_urb_in_use;		   /* write urb in use indicator */
100 	int write_urb_interval;            /* interval to use for write urb */
101 	int read_urb_interval;             /* interval to use for read urb */
102 	int comm_is_ok;                    /* true if communication is (still) ok */
103 	__u8 line_control;	   	   /* holds dtr / rts value */
104 	__u8 current_status;	   	   /* received from last read - info on dsr,cts,cd,ri,etc */
105 	__u8 current_config;	   	   /* stores the current configuration byte */
106 	__u8 rx_flags;			   /* throttling - used from whiteheat/ftdi_sio */
107 	enum packet_format pkt_fmt;	   /* format to use for packet send / receive */
108 	int get_cfg_unsafe;		   /* If true, the CYPRESS_GET_CONFIG is unsafe */
109 	int baud_rate;			   /* stores current baud rate in
110 					      integer form */
111 	char prev_status;		   /* used for TIOCMIWAIT */
112 };
113 
114 /* function prototypes for the Cypress USB to serial device */
115 static int  cypress_earthmate_port_probe(struct usb_serial_port *port);
116 static int  cypress_hidcom_port_probe(struct usb_serial_port *port);
117 static int  cypress_ca42v2_port_probe(struct usb_serial_port *port);
118 static void cypress_port_remove(struct usb_serial_port *port);
119 static int  cypress_open(struct tty_struct *tty, struct usb_serial_port *port);
120 static void cypress_close(struct usb_serial_port *port);
121 static void cypress_dtr_rts(struct usb_serial_port *port, int on);
122 static int  cypress_write(struct tty_struct *tty, struct usb_serial_port *port,
123 			const unsigned char *buf, int count);
124 static void cypress_send(struct usb_serial_port *port);
125 static unsigned int cypress_write_room(struct tty_struct *tty);
126 static void cypress_earthmate_init_termios(struct tty_struct *tty);
127 static void cypress_set_termios(struct tty_struct *tty,
128 				struct usb_serial_port *port,
129 				const struct ktermios *old_termios);
130 static int  cypress_tiocmget(struct tty_struct *tty);
131 static int  cypress_tiocmset(struct tty_struct *tty,
132 			unsigned int set, unsigned int clear);
133 static unsigned int cypress_chars_in_buffer(struct tty_struct *tty);
134 static void cypress_throttle(struct tty_struct *tty);
135 static void cypress_unthrottle(struct tty_struct *tty);
136 static void cypress_set_dead(struct usb_serial_port *port);
137 static void cypress_read_int_callback(struct urb *urb);
138 static void cypress_write_int_callback(struct urb *urb);
139 
140 static struct usb_serial_driver cypress_earthmate_device = {
141 	.driver = {
142 		.name =			"earthmate",
143 	},
144 	.description =			"DeLorme Earthmate USB",
145 	.id_table =			id_table_earthmate,
146 	.num_ports =			1,
147 	.port_probe =			cypress_earthmate_port_probe,
148 	.port_remove =			cypress_port_remove,
149 	.open =				cypress_open,
150 	.close =			cypress_close,
151 	.dtr_rts =			cypress_dtr_rts,
152 	.write =			cypress_write,
153 	.write_room =			cypress_write_room,
154 	.init_termios =			cypress_earthmate_init_termios,
155 	.set_termios =			cypress_set_termios,
156 	.tiocmget =			cypress_tiocmget,
157 	.tiocmset =			cypress_tiocmset,
158 	.tiocmiwait =			usb_serial_generic_tiocmiwait,
159 	.chars_in_buffer =		cypress_chars_in_buffer,
160 	.throttle =		 	cypress_throttle,
161 	.unthrottle =			cypress_unthrottle,
162 	.read_int_callback =		cypress_read_int_callback,
163 	.write_int_callback =		cypress_write_int_callback,
164 };
165 
166 static struct usb_serial_driver cypress_hidcom_device = {
167 	.driver = {
168 		.name =			"cyphidcom",
169 	},
170 	.description =			"HID->COM RS232 Adapter",
171 	.id_table =			id_table_cyphidcomrs232,
172 	.num_ports =			1,
173 	.port_probe =			cypress_hidcom_port_probe,
174 	.port_remove =			cypress_port_remove,
175 	.open =				cypress_open,
176 	.close =			cypress_close,
177 	.dtr_rts =			cypress_dtr_rts,
178 	.write =			cypress_write,
179 	.write_room =			cypress_write_room,
180 	.set_termios =			cypress_set_termios,
181 	.tiocmget =			cypress_tiocmget,
182 	.tiocmset =			cypress_tiocmset,
183 	.tiocmiwait =			usb_serial_generic_tiocmiwait,
184 	.chars_in_buffer =		cypress_chars_in_buffer,
185 	.throttle =			cypress_throttle,
186 	.unthrottle =			cypress_unthrottle,
187 	.read_int_callback =		cypress_read_int_callback,
188 	.write_int_callback =		cypress_write_int_callback,
189 };
190 
191 static struct usb_serial_driver cypress_ca42v2_device = {
192 	.driver = {
193 		.name =			"nokiaca42v2",
194 	},
195 	.description =			"Nokia CA-42 V2 Adapter",
196 	.id_table =			id_table_nokiaca42v2,
197 	.num_ports =			1,
198 	.port_probe =			cypress_ca42v2_port_probe,
199 	.port_remove =			cypress_port_remove,
200 	.open =				cypress_open,
201 	.close =			cypress_close,
202 	.dtr_rts =			cypress_dtr_rts,
203 	.write =			cypress_write,
204 	.write_room =			cypress_write_room,
205 	.set_termios =			cypress_set_termios,
206 	.tiocmget =			cypress_tiocmget,
207 	.tiocmset =			cypress_tiocmset,
208 	.tiocmiwait =			usb_serial_generic_tiocmiwait,
209 	.chars_in_buffer =		cypress_chars_in_buffer,
210 	.throttle =			cypress_throttle,
211 	.unthrottle =			cypress_unthrottle,
212 	.read_int_callback =		cypress_read_int_callback,
213 	.write_int_callback =		cypress_write_int_callback,
214 };
215 
216 static struct usb_serial_driver * const serial_drivers[] = {
217 	&cypress_earthmate_device, &cypress_hidcom_device,
218 	&cypress_ca42v2_device, NULL
219 };
220 
221 /*****************************************************************************
222  * Cypress serial helper functions
223  *****************************************************************************/
224 
225 /* FRWD Dongle hidcom needs to skip reset and speed checks */
226 static inline bool is_frwd(struct usb_device *dev)
227 {
228 	return ((le16_to_cpu(dev->descriptor.idVendor) == VENDOR_ID_FRWD) &&
229 		(le16_to_cpu(dev->descriptor.idProduct) == PRODUCT_ID_CYPHIDCOM_FRWD));
230 }
231 
232 static int analyze_baud_rate(struct usb_serial_port *port, speed_t new_rate)
233 {
234 	struct cypress_private *priv;
235 	priv = usb_get_serial_port_data(port);
236 
237 	if (unstable_bauds)
238 		return new_rate;
239 
240 	/* FRWD Dongle uses 115200 bps */
241 	if (is_frwd(port->serial->dev))
242 		return new_rate;
243 
244 	/*
245 	 * The general purpose firmware for the Cypress M8 allows for
246 	 * a maximum speed of 57600bps (I have no idea whether DeLorme
247 	 * chose to use the general purpose firmware or not), if you
248 	 * need to modify this speed setting for your own project
249 	 * please add your own chiptype and modify the code likewise.
250 	 * The Cypress HID->COM device will work successfully up to
251 	 * 115200bps (but the actual throughput is around 3kBps).
252 	 */
253 	if (port->serial->dev->speed == USB_SPEED_LOW) {
254 		/*
255 		 * Mike Isely <isely@pobox.com> 2-Feb-2008: The
256 		 * Cypress app note that describes this mechanism
257 		 * states that the low-speed part can't handle more
258 		 * than 800 bytes/sec, in which case 4800 baud is the
259 		 * safest speed for a part like that.
260 		 */
261 		if (new_rate > 4800) {
262 			dev_dbg(&port->dev,
263 				"%s - failed setting baud rate, device incapable speed %d\n",
264 				__func__, new_rate);
265 			return -1;
266 		}
267 	}
268 	switch (priv->chiptype) {
269 	case CT_EARTHMATE:
270 		if (new_rate <= 600) {
271 			/* 300 and 600 baud rates are supported under
272 			 * the generic firmware, but are not used with
273 			 * NMEA and SiRF protocols */
274 			dev_dbg(&port->dev,
275 				"%s - failed setting baud rate, unsupported speed of %d on Earthmate GPS\n",
276 				__func__, new_rate);
277 			return -1;
278 		}
279 		break;
280 	default:
281 		break;
282 	}
283 	return new_rate;
284 }
285 
286 
287 /* This function can either set or retrieve the current serial line settings */
288 static int cypress_serial_control(struct tty_struct *tty,
289 	struct usb_serial_port *port, speed_t baud_rate, int data_bits,
290 	int stop_bits, int parity_enable, int parity_type, int reset,
291 	int cypress_request_type)
292 {
293 	int new_baudrate = 0, retval = 0, tries = 0;
294 	struct cypress_private *priv;
295 	struct device *dev = &port->dev;
296 	u8 *feature_buffer;
297 	const unsigned int feature_len = 5;
298 	unsigned long flags;
299 
300 	priv = usb_get_serial_port_data(port);
301 
302 	if (!priv->comm_is_ok)
303 		return -ENODEV;
304 
305 	feature_buffer = kcalloc(feature_len, sizeof(u8), GFP_KERNEL);
306 	if (!feature_buffer)
307 		return -ENOMEM;
308 
309 	switch (cypress_request_type) {
310 	case CYPRESS_SET_CONFIG:
311 		/* 0 means 'Hang up' so doesn't change the true bit rate */
312 		new_baudrate = priv->baud_rate;
313 		if (baud_rate && baud_rate != priv->baud_rate) {
314 			dev_dbg(dev, "%s - baud rate is changing\n", __func__);
315 			retval = analyze_baud_rate(port, baud_rate);
316 			if (retval >= 0) {
317 				new_baudrate = retval;
318 				dev_dbg(dev, "%s - New baud rate set to %d\n",
319 					__func__, new_baudrate);
320 			}
321 		}
322 		dev_dbg(dev, "%s - baud rate is being sent as %d\n", __func__,
323 			new_baudrate);
324 
325 		/* fill the feature_buffer with new configuration */
326 		put_unaligned_le32(new_baudrate, feature_buffer);
327 		feature_buffer[4] |= data_bits - 5;   /* assign data bits in 2 bit space ( max 3 ) */
328 		/* 1 bit gap */
329 		feature_buffer[4] |= (stop_bits << 3);   /* assign stop bits in 1 bit space */
330 		feature_buffer[4] |= (parity_enable << 4);   /* assign parity flag in 1 bit space */
331 		feature_buffer[4] |= (parity_type << 5);   /* assign parity type in 1 bit space */
332 		/* 1 bit gap */
333 		feature_buffer[4] |= (reset << 7);   /* assign reset at end of byte, 1 bit space */
334 
335 		dev_dbg(dev, "%s - device is being sent this feature report:\n", __func__);
336 		dev_dbg(dev, "%s - %02X - %02X - %02X - %02X - %02X\n", __func__,
337 			feature_buffer[0], feature_buffer[1],
338 			feature_buffer[2], feature_buffer[3],
339 			feature_buffer[4]);
340 
341 		do {
342 			retval = usb_control_msg(port->serial->dev,
343 					usb_sndctrlpipe(port->serial->dev, 0),
344 					HID_REQ_SET_REPORT,
345 					USB_DIR_OUT | USB_RECIP_INTERFACE | USB_TYPE_CLASS,
346 					0x0300, 0, feature_buffer,
347 					feature_len, 500);
348 
349 			if (tries++ >= 3)
350 				break;
351 
352 		} while (retval != feature_len &&
353 			 retval != -ENODEV);
354 
355 		if (retval != feature_len) {
356 			dev_err(dev, "%s - failed sending serial line settings - %d\n",
357 				__func__, retval);
358 			cypress_set_dead(port);
359 		} else {
360 			spin_lock_irqsave(&priv->lock, flags);
361 			priv->baud_rate = new_baudrate;
362 			priv->current_config = feature_buffer[4];
363 			spin_unlock_irqrestore(&priv->lock, flags);
364 			/* If we asked for a speed change encode it */
365 			if (baud_rate)
366 				tty_encode_baud_rate(tty,
367 					new_baudrate, new_baudrate);
368 		}
369 	break;
370 	case CYPRESS_GET_CONFIG:
371 		if (priv->get_cfg_unsafe) {
372 			/* Not implemented for this device,
373 			   and if we try to do it we're likely
374 			   to crash the hardware. */
375 			retval = -ENOTTY;
376 			goto out;
377 		}
378 		dev_dbg(dev, "%s - retrieving serial line settings\n", __func__);
379 		do {
380 			retval = usb_control_msg(port->serial->dev,
381 					usb_rcvctrlpipe(port->serial->dev, 0),
382 					HID_REQ_GET_REPORT,
383 					USB_DIR_IN | USB_RECIP_INTERFACE | USB_TYPE_CLASS,
384 					0x0300, 0, feature_buffer,
385 					feature_len, 500);
386 
387 			if (tries++ >= 3)
388 				break;
389 		} while (retval != feature_len
390 						&& retval != -ENODEV);
391 
392 		if (retval != feature_len) {
393 			dev_err(dev, "%s - failed to retrieve serial line settings - %d\n",
394 				__func__, retval);
395 			cypress_set_dead(port);
396 			goto out;
397 		} else {
398 			spin_lock_irqsave(&priv->lock, flags);
399 			/* store the config in one byte, and later
400 			   use bit masks to check values */
401 			priv->current_config = feature_buffer[4];
402 			priv->baud_rate = get_unaligned_le32(feature_buffer);
403 			spin_unlock_irqrestore(&priv->lock, flags);
404 		}
405 	}
406 	spin_lock_irqsave(&priv->lock, flags);
407 	++priv->cmd_count;
408 	spin_unlock_irqrestore(&priv->lock, flags);
409 out:
410 	kfree(feature_buffer);
411 	return retval;
412 } /* cypress_serial_control */
413 
414 
415 static void cypress_set_dead(struct usb_serial_port *port)
416 {
417 	struct cypress_private *priv = usb_get_serial_port_data(port);
418 	unsigned long flags;
419 
420 	spin_lock_irqsave(&priv->lock, flags);
421 	if (!priv->comm_is_ok) {
422 		spin_unlock_irqrestore(&priv->lock, flags);
423 		return;
424 	}
425 	priv->comm_is_ok = 0;
426 	spin_unlock_irqrestore(&priv->lock, flags);
427 
428 	dev_err(&port->dev, "cypress_m8 suspending failing port %d - "
429 		"interval might be too short\n", port->port_number);
430 }
431 
432 
433 /*****************************************************************************
434  * Cypress serial driver functions
435  *****************************************************************************/
436 
437 
438 static int cypress_generic_port_probe(struct usb_serial_port *port)
439 {
440 	struct usb_serial *serial = port->serial;
441 	struct cypress_private *priv;
442 
443 	if (!port->interrupt_out_urb || !port->interrupt_in_urb) {
444 		dev_err(&port->dev, "required endpoint is missing\n");
445 		return -ENODEV;
446 	}
447 
448 	priv = kzalloc(sizeof(struct cypress_private), GFP_KERNEL);
449 	if (!priv)
450 		return -ENOMEM;
451 
452 	priv->comm_is_ok = !0;
453 	spin_lock_init(&priv->lock);
454 	if (kfifo_alloc(&priv->write_fifo, CYPRESS_BUF_SIZE, GFP_KERNEL)) {
455 		kfree(priv);
456 		return -ENOMEM;
457 	}
458 
459 	/* Skip reset for FRWD device. It is a workaound:
460 	   device hangs if it receives SET_CONFIGURE in Configured
461 	   state. */
462 	if (!is_frwd(serial->dev))
463 		usb_reset_configuration(serial->dev);
464 
465 	priv->cmd_ctrl = 0;
466 	priv->line_control = 0;
467 	priv->rx_flags = 0;
468 	/* Default packet format setting is determined by packet size.
469 	   Anything with a size larger then 9 must have a separate
470 	   count field since the 3 bit count field is otherwise too
471 	   small.  Otherwise we can use the slightly more compact
472 	   format.  This is in accordance with the cypress_m8 serial
473 	   converter app note. */
474 	if (port->interrupt_out_size > 9)
475 		priv->pkt_fmt = packet_format_1;
476 	else
477 		priv->pkt_fmt = packet_format_2;
478 
479 	if (interval > 0) {
480 		priv->write_urb_interval = interval;
481 		priv->read_urb_interval = interval;
482 		dev_dbg(&port->dev, "%s - read & write intervals forced to %d\n",
483 			__func__, interval);
484 	} else {
485 		priv->write_urb_interval = port->interrupt_out_urb->interval;
486 		priv->read_urb_interval = port->interrupt_in_urb->interval;
487 		dev_dbg(&port->dev, "%s - intervals: read=%d write=%d\n",
488 			__func__, priv->read_urb_interval,
489 			priv->write_urb_interval);
490 	}
491 	usb_set_serial_port_data(port, priv);
492 
493 	port->port.drain_delay = 256;
494 
495 	return 0;
496 }
497 
498 
499 static int cypress_earthmate_port_probe(struct usb_serial_port *port)
500 {
501 	struct usb_serial *serial = port->serial;
502 	struct cypress_private *priv;
503 	int ret;
504 
505 	ret = cypress_generic_port_probe(port);
506 	if (ret) {
507 		dev_dbg(&port->dev, "%s - Failed setting up port\n", __func__);
508 		return ret;
509 	}
510 
511 	priv = usb_get_serial_port_data(port);
512 	priv->chiptype = CT_EARTHMATE;
513 	/* All Earthmate devices use the separated-count packet
514 	   format!  Idiotic. */
515 	priv->pkt_fmt = packet_format_1;
516 	if (serial->dev->descriptor.idProduct !=
517 				cpu_to_le16(PRODUCT_ID_EARTHMATEUSB)) {
518 		/* The old original USB Earthmate seemed able to
519 		   handle GET_CONFIG requests; everything they've
520 		   produced since that time crashes if this command is
521 		   attempted :-( */
522 		dev_dbg(&port->dev,
523 			"%s - Marking this device as unsafe for GET_CONFIG commands\n",
524 			__func__);
525 		priv->get_cfg_unsafe = !0;
526 	}
527 
528 	return 0;
529 }
530 
531 static int cypress_hidcom_port_probe(struct usb_serial_port *port)
532 {
533 	struct cypress_private *priv;
534 	int ret;
535 
536 	ret = cypress_generic_port_probe(port);
537 	if (ret) {
538 		dev_dbg(&port->dev, "%s - Failed setting up port\n", __func__);
539 		return ret;
540 	}
541 
542 	priv = usb_get_serial_port_data(port);
543 	priv->chiptype = CT_CYPHIDCOM;
544 
545 	return 0;
546 }
547 
548 static int cypress_ca42v2_port_probe(struct usb_serial_port *port)
549 {
550 	struct cypress_private *priv;
551 	int ret;
552 
553 	ret = cypress_generic_port_probe(port);
554 	if (ret) {
555 		dev_dbg(&port->dev, "%s - Failed setting up port\n", __func__);
556 		return ret;
557 	}
558 
559 	priv = usb_get_serial_port_data(port);
560 	priv->chiptype = CT_CA42V2;
561 
562 	return 0;
563 }
564 
565 static void cypress_port_remove(struct usb_serial_port *port)
566 {
567 	struct cypress_private *priv;
568 
569 	priv = usb_get_serial_port_data(port);
570 
571 	kfifo_free(&priv->write_fifo);
572 	kfree(priv);
573 }
574 
575 static int cypress_open(struct tty_struct *tty, struct usb_serial_port *port)
576 {
577 	struct cypress_private *priv = usb_get_serial_port_data(port);
578 	struct usb_serial *serial = port->serial;
579 	unsigned long flags;
580 	int result = 0;
581 
582 	if (!priv->comm_is_ok)
583 		return -EIO;
584 
585 	/* clear halts before open */
586 	usb_clear_halt(serial->dev, 0x81);
587 	usb_clear_halt(serial->dev, 0x02);
588 
589 	spin_lock_irqsave(&priv->lock, flags);
590 	/* reset read/write statistics */
591 	priv->bytes_in = 0;
592 	priv->bytes_out = 0;
593 	priv->cmd_count = 0;
594 	priv->rx_flags = 0;
595 	spin_unlock_irqrestore(&priv->lock, flags);
596 
597 	/* Set termios */
598 	cypress_send(port);
599 
600 	if (tty)
601 		cypress_set_termios(tty, port, NULL);
602 
603 	/* setup the port and start reading from the device */
604 	usb_fill_int_urb(port->interrupt_in_urb, serial->dev,
605 		usb_rcvintpipe(serial->dev, port->interrupt_in_endpointAddress),
606 		port->interrupt_in_urb->transfer_buffer,
607 		port->interrupt_in_urb->transfer_buffer_length,
608 		cypress_read_int_callback, port, priv->read_urb_interval);
609 	result = usb_submit_urb(port->interrupt_in_urb, GFP_KERNEL);
610 
611 	if (result) {
612 		dev_err(&port->dev,
613 			"%s - failed submitting read urb, error %d\n",
614 							__func__, result);
615 		cypress_set_dead(port);
616 	}
617 
618 	return result;
619 } /* cypress_open */
620 
621 static void cypress_dtr_rts(struct usb_serial_port *port, int on)
622 {
623 	struct cypress_private *priv = usb_get_serial_port_data(port);
624 	/* drop dtr and rts */
625 	spin_lock_irq(&priv->lock);
626 	if (on == 0)
627 		priv->line_control = 0;
628 	else
629 		priv->line_control = CONTROL_DTR | CONTROL_RTS;
630 	priv->cmd_ctrl = 1;
631 	spin_unlock_irq(&priv->lock);
632 	cypress_write(NULL, port, NULL, 0);
633 }
634 
635 static void cypress_close(struct usb_serial_port *port)
636 {
637 	struct cypress_private *priv = usb_get_serial_port_data(port);
638 	unsigned long flags;
639 
640 	spin_lock_irqsave(&priv->lock, flags);
641 	kfifo_reset_out(&priv->write_fifo);
642 	spin_unlock_irqrestore(&priv->lock, flags);
643 
644 	dev_dbg(&port->dev, "%s - stopping urbs\n", __func__);
645 	usb_kill_urb(port->interrupt_in_urb);
646 	usb_kill_urb(port->interrupt_out_urb);
647 
648 	if (stats)
649 		dev_info(&port->dev, "Statistics: %d Bytes In | %d Bytes Out | %d Commands Issued\n",
650 			priv->bytes_in, priv->bytes_out, priv->cmd_count);
651 } /* cypress_close */
652 
653 
654 static int cypress_write(struct tty_struct *tty, struct usb_serial_port *port,
655 					const unsigned char *buf, int count)
656 {
657 	struct cypress_private *priv = usb_get_serial_port_data(port);
658 
659 	dev_dbg(&port->dev, "%s - %d bytes\n", __func__, count);
660 
661 	/* line control commands, which need to be executed immediately,
662 	   are not put into the buffer for obvious reasons.
663 	 */
664 	if (priv->cmd_ctrl) {
665 		count = 0;
666 		goto finish;
667 	}
668 
669 	if (!count)
670 		return count;
671 
672 	count = kfifo_in_locked(&priv->write_fifo, buf, count, &priv->lock);
673 
674 finish:
675 	cypress_send(port);
676 
677 	return count;
678 } /* cypress_write */
679 
680 
681 static void cypress_send(struct usb_serial_port *port)
682 {
683 	int count = 0, result, offset, actual_size;
684 	struct cypress_private *priv = usb_get_serial_port_data(port);
685 	struct device *dev = &port->dev;
686 	unsigned long flags;
687 
688 	if (!priv->comm_is_ok)
689 		return;
690 
691 	dev_dbg(dev, "%s - interrupt out size is %d\n", __func__,
692 		port->interrupt_out_size);
693 
694 	spin_lock_irqsave(&priv->lock, flags);
695 	if (priv->write_urb_in_use) {
696 		dev_dbg(dev, "%s - can't write, urb in use\n", __func__);
697 		spin_unlock_irqrestore(&priv->lock, flags);
698 		return;
699 	}
700 	spin_unlock_irqrestore(&priv->lock, flags);
701 
702 	/* clear buffer */
703 	memset(port->interrupt_out_urb->transfer_buffer, 0,
704 						port->interrupt_out_size);
705 
706 	spin_lock_irqsave(&priv->lock, flags);
707 	switch (priv->pkt_fmt) {
708 	default:
709 	case packet_format_1:
710 		/* this is for the CY7C64013... */
711 		offset = 2;
712 		port->interrupt_out_buffer[0] = priv->line_control;
713 		break;
714 	case packet_format_2:
715 		/* this is for the CY7C63743... */
716 		offset = 1;
717 		port->interrupt_out_buffer[0] = priv->line_control;
718 		break;
719 	}
720 
721 	if (priv->line_control & CONTROL_RESET)
722 		priv->line_control &= ~CONTROL_RESET;
723 
724 	if (priv->cmd_ctrl) {
725 		priv->cmd_count++;
726 		dev_dbg(dev, "%s - line control command being issued\n", __func__);
727 		spin_unlock_irqrestore(&priv->lock, flags);
728 		goto send;
729 	} else
730 		spin_unlock_irqrestore(&priv->lock, flags);
731 
732 	count = kfifo_out_locked(&priv->write_fifo,
733 					&port->interrupt_out_buffer[offset],
734 					port->interrupt_out_size - offset,
735 					&priv->lock);
736 	if (count == 0)
737 		return;
738 
739 	switch (priv->pkt_fmt) {
740 	default:
741 	case packet_format_1:
742 		port->interrupt_out_buffer[1] = count;
743 		break;
744 	case packet_format_2:
745 		port->interrupt_out_buffer[0] |= count;
746 	}
747 
748 	dev_dbg(dev, "%s - count is %d\n", __func__, count);
749 
750 send:
751 	spin_lock_irqsave(&priv->lock, flags);
752 	priv->write_urb_in_use = 1;
753 	spin_unlock_irqrestore(&priv->lock, flags);
754 
755 	if (priv->cmd_ctrl)
756 		actual_size = 1;
757 	else
758 		actual_size = count +
759 			      (priv->pkt_fmt == packet_format_1 ? 2 : 1);
760 
761 	usb_serial_debug_data(dev, __func__, port->interrupt_out_size,
762 			      port->interrupt_out_urb->transfer_buffer);
763 
764 	usb_fill_int_urb(port->interrupt_out_urb, port->serial->dev,
765 		usb_sndintpipe(port->serial->dev, port->interrupt_out_endpointAddress),
766 		port->interrupt_out_buffer, actual_size,
767 		cypress_write_int_callback, port, priv->write_urb_interval);
768 	result = usb_submit_urb(port->interrupt_out_urb, GFP_ATOMIC);
769 	if (result) {
770 		dev_err_console(port,
771 				"%s - failed submitting write urb, error %d\n",
772 							__func__, result);
773 		priv->write_urb_in_use = 0;
774 		cypress_set_dead(port);
775 	}
776 
777 	spin_lock_irqsave(&priv->lock, flags);
778 	if (priv->cmd_ctrl)
779 		priv->cmd_ctrl = 0;
780 
781 	/* do not count the line control and size bytes */
782 	priv->bytes_out += count;
783 	spin_unlock_irqrestore(&priv->lock, flags);
784 
785 	usb_serial_port_softint(port);
786 } /* cypress_send */
787 
788 
789 /* returns how much space is available in the soft buffer */
790 static unsigned int cypress_write_room(struct tty_struct *tty)
791 {
792 	struct usb_serial_port *port = tty->driver_data;
793 	struct cypress_private *priv = usb_get_serial_port_data(port);
794 	unsigned int room;
795 	unsigned long flags;
796 
797 	spin_lock_irqsave(&priv->lock, flags);
798 	room = kfifo_avail(&priv->write_fifo);
799 	spin_unlock_irqrestore(&priv->lock, flags);
800 
801 	dev_dbg(&port->dev, "%s - returns %u\n", __func__, room);
802 	return room;
803 }
804 
805 
806 static int cypress_tiocmget(struct tty_struct *tty)
807 {
808 	struct usb_serial_port *port = tty->driver_data;
809 	struct cypress_private *priv = usb_get_serial_port_data(port);
810 	__u8 status, control;
811 	unsigned int result = 0;
812 	unsigned long flags;
813 
814 	spin_lock_irqsave(&priv->lock, flags);
815 	control = priv->line_control;
816 	status = priv->current_status;
817 	spin_unlock_irqrestore(&priv->lock, flags);
818 
819 	result = ((control & CONTROL_DTR)        ? TIOCM_DTR : 0)
820 		| ((control & CONTROL_RTS)       ? TIOCM_RTS : 0)
821 		| ((status & UART_CTS)        ? TIOCM_CTS : 0)
822 		| ((status & UART_DSR)        ? TIOCM_DSR : 0)
823 		| ((status & UART_RI)         ? TIOCM_RI  : 0)
824 		| ((status & UART_CD)         ? TIOCM_CD  : 0);
825 
826 	dev_dbg(&port->dev, "%s - result = %x\n", __func__, result);
827 
828 	return result;
829 }
830 
831 
832 static int cypress_tiocmset(struct tty_struct *tty,
833 			       unsigned int set, unsigned int clear)
834 {
835 	struct usb_serial_port *port = tty->driver_data;
836 	struct cypress_private *priv = usb_get_serial_port_data(port);
837 	unsigned long flags;
838 
839 	spin_lock_irqsave(&priv->lock, flags);
840 	if (set & TIOCM_RTS)
841 		priv->line_control |= CONTROL_RTS;
842 	if (set & TIOCM_DTR)
843 		priv->line_control |= CONTROL_DTR;
844 	if (clear & TIOCM_RTS)
845 		priv->line_control &= ~CONTROL_RTS;
846 	if (clear & TIOCM_DTR)
847 		priv->line_control &= ~CONTROL_DTR;
848 	priv->cmd_ctrl = 1;
849 	spin_unlock_irqrestore(&priv->lock, flags);
850 
851 	return cypress_write(tty, port, NULL, 0);
852 }
853 
854 static void cypress_earthmate_init_termios(struct tty_struct *tty)
855 {
856 	tty_encode_baud_rate(tty, 4800, 4800);
857 }
858 
859 static void cypress_set_termios(struct tty_struct *tty,
860 				struct usb_serial_port *port,
861 				const 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 	/* Unsupported features need clearing */
872 	tty->termios.c_cflag &= ~(CMSPAR|CRTSCTS);
873 
874 	cflag = tty->termios.c_cflag;
875 
876 	/* set number of data bits, parity, stop bits */
877 	/* when parity is disabled the parity type bit is ignored */
878 
879 	/* 1 means 2 stop bits, 0 means 1 stop bit */
880 	stop_bits = cflag & CSTOPB ? 1 : 0;
881 
882 	if (cflag & PARENB) {
883 		parity_enable = 1;
884 		/* 1 means odd parity, 0 means even parity */
885 		parity_type = cflag & PARODD ? 1 : 0;
886 	} else
887 		parity_enable = parity_type = 0;
888 
889 	data_bits = tty_get_char_size(cflag);
890 
891 	spin_lock_irqsave(&priv->lock, flags);
892 	oldlines = priv->line_control;
893 	if ((cflag & CBAUD) == B0) {
894 		/* drop dtr and rts */
895 		dev_dbg(dev, "%s - dropping the lines, baud rate 0bps\n", __func__);
896 		priv->line_control &= ~(CONTROL_DTR | CONTROL_RTS);
897 	} else
898 		priv->line_control = (CONTROL_DTR | CONTROL_RTS);
899 	spin_unlock_irqrestore(&priv->lock, flags);
900 
901 	dev_dbg(dev, "%s - sending %d stop_bits, %d parity_enable, %d parity_type, %d data_bits (+5)\n",
902 		__func__, stop_bits, parity_enable, parity_type, data_bits);
903 
904 	cypress_serial_control(tty, port, tty_get_baud_rate(tty),
905 			data_bits, stop_bits,
906 			parity_enable, parity_type,
907 			0, CYPRESS_SET_CONFIG);
908 
909 	/* we perform a CYPRESS_GET_CONFIG so that the current settings are
910 	 * filled into the private structure this should confirm that all is
911 	 * working if it returns what we just set */
912 	cypress_serial_control(tty, port, 0, 0, 0, 0, 0, 0, CYPRESS_GET_CONFIG);
913 
914 	/* Here we can define custom tty settings for devices; the main tty
915 	 * termios flag base comes from empeg.c */
916 
917 	spin_lock_irqsave(&priv->lock, flags);
918 	if (priv->chiptype == CT_EARTHMATE && priv->baud_rate == 4800) {
919 		dev_dbg(dev, "Using custom termios settings for a baud rate of 4800bps.\n");
920 		/* define custom termios settings for NMEA protocol */
921 
922 		tty->termios.c_iflag /* input modes - */
923 			&= ~(IGNBRK  /* disable ignore break */
924 			| BRKINT     /* disable break causes interrupt */
925 			| PARMRK     /* disable mark parity errors */
926 			| ISTRIP     /* disable clear high bit of input char */
927 			| INLCR      /* disable translate NL to CR */
928 			| IGNCR      /* disable ignore CR */
929 			| ICRNL      /* disable translate CR to NL */
930 			| IXON);     /* disable enable XON/XOFF flow control */
931 
932 		tty->termios.c_oflag /* output modes */
933 			&= ~OPOST;    /* disable postprocess output char */
934 
935 		tty->termios.c_lflag /* line discipline modes */
936 			&= ~(ECHO     /* disable echo input characters */
937 			| ECHONL      /* disable echo new line */
938 			| ICANON      /* disable erase, kill, werase, and rprnt
939 					 special characters */
940 			| ISIG        /* disable interrupt, quit, and suspend
941 					 special characters */
942 			| IEXTEN);    /* disable non-POSIX special characters */
943 	} /* CT_CYPHIDCOM: Application should handle this for device */
944 
945 	linechange = (priv->line_control != oldlines);
946 	spin_unlock_irqrestore(&priv->lock, flags);
947 
948 	/* if necessary, set lines */
949 	if (linechange) {
950 		priv->cmd_ctrl = 1;
951 		cypress_write(tty, port, NULL, 0);
952 	}
953 } /* cypress_set_termios */
954 
955 
956 /* returns amount of data still left in soft buffer */
957 static unsigned int cypress_chars_in_buffer(struct tty_struct *tty)
958 {
959 	struct usb_serial_port *port = tty->driver_data;
960 	struct cypress_private *priv = usb_get_serial_port_data(port);
961 	unsigned int chars;
962 	unsigned long flags;
963 
964 	spin_lock_irqsave(&priv->lock, flags);
965 	chars = kfifo_len(&priv->write_fifo);
966 	spin_unlock_irqrestore(&priv->lock, flags);
967 
968 	dev_dbg(&port->dev, "%s - returns %u\n", __func__, chars);
969 	return chars;
970 }
971 
972 
973 static void cypress_throttle(struct tty_struct *tty)
974 {
975 	struct usb_serial_port *port = tty->driver_data;
976 	struct cypress_private *priv = usb_get_serial_port_data(port);
977 
978 	spin_lock_irq(&priv->lock);
979 	priv->rx_flags = THROTTLED;
980 	spin_unlock_irq(&priv->lock);
981 }
982 
983 
984 static void cypress_unthrottle(struct tty_struct *tty)
985 {
986 	struct usb_serial_port *port = tty->driver_data;
987 	struct cypress_private *priv = usb_get_serial_port_data(port);
988 	int actually_throttled, result;
989 
990 	spin_lock_irq(&priv->lock);
991 	actually_throttled = priv->rx_flags & ACTUALLY_THROTTLED;
992 	priv->rx_flags = 0;
993 	spin_unlock_irq(&priv->lock);
994 
995 	if (!priv->comm_is_ok)
996 		return;
997 
998 	if (actually_throttled) {
999 		result = usb_submit_urb(port->interrupt_in_urb, GFP_KERNEL);
1000 		if (result) {
1001 			dev_err(&port->dev, "%s - failed submitting read urb, "
1002 					"error %d\n", __func__, result);
1003 			cypress_set_dead(port);
1004 		}
1005 	}
1006 }
1007 
1008 
1009 static void cypress_read_int_callback(struct urb *urb)
1010 {
1011 	struct usb_serial_port *port = urb->context;
1012 	struct cypress_private *priv = usb_get_serial_port_data(port);
1013 	struct device *dev = &urb->dev->dev;
1014 	struct tty_struct *tty;
1015 	unsigned char *data = urb->transfer_buffer;
1016 	unsigned long flags;
1017 	char tty_flag = TTY_NORMAL;
1018 	int bytes = 0;
1019 	int result;
1020 	int i = 0;
1021 	int status = urb->status;
1022 
1023 	switch (status) {
1024 	case 0: /* success */
1025 		break;
1026 	case -ECONNRESET:
1027 	case -ENOENT:
1028 	case -ESHUTDOWN:
1029 		/* precursor to disconnect so just go away */
1030 		return;
1031 	case -EPIPE:
1032 		/* Can't call usb_clear_halt while in_interrupt */
1033 		fallthrough;
1034 	default:
1035 		/* something ugly is going on... */
1036 		dev_err(dev, "%s - unexpected nonzero read status received: %d\n",
1037 			__func__, status);
1038 		cypress_set_dead(port);
1039 		return;
1040 	}
1041 
1042 	spin_lock_irqsave(&priv->lock, flags);
1043 	if (priv->rx_flags & THROTTLED) {
1044 		dev_dbg(dev, "%s - now throttling\n", __func__);
1045 		priv->rx_flags |= ACTUALLY_THROTTLED;
1046 		spin_unlock_irqrestore(&priv->lock, flags);
1047 		return;
1048 	}
1049 	spin_unlock_irqrestore(&priv->lock, flags);
1050 
1051 	tty = tty_port_tty_get(&port->port);
1052 	if (!tty) {
1053 		dev_dbg(dev, "%s - bad tty pointer - exiting\n", __func__);
1054 		return;
1055 	}
1056 
1057 	spin_lock_irqsave(&priv->lock, flags);
1058 	result = urb->actual_length;
1059 	switch (priv->pkt_fmt) {
1060 	default:
1061 	case packet_format_1:
1062 		/* This is for the CY7C64013... */
1063 		priv->current_status = data[0] & 0xF8;
1064 		bytes = data[1] + 2;
1065 		i = 2;
1066 		break;
1067 	case packet_format_2:
1068 		/* This is for the CY7C63743... */
1069 		priv->current_status = data[0] & 0xF8;
1070 		bytes = (data[0] & 0x07) + 1;
1071 		i = 1;
1072 		break;
1073 	}
1074 	spin_unlock_irqrestore(&priv->lock, flags);
1075 	if (result < bytes) {
1076 		dev_dbg(dev,
1077 			"%s - wrong packet size - received %d bytes but packet said %d bytes\n",
1078 			__func__, result, bytes);
1079 		goto continue_read;
1080 	}
1081 
1082 	usb_serial_debug_data(&port->dev, __func__, urb->actual_length, data);
1083 
1084 	spin_lock_irqsave(&priv->lock, flags);
1085 	/* check to see if status has changed */
1086 	if (priv->current_status != priv->prev_status) {
1087 		u8 delta = priv->current_status ^ priv->prev_status;
1088 
1089 		if (delta & UART_MSR_MASK) {
1090 			if (delta & UART_CTS)
1091 				port->icount.cts++;
1092 			if (delta & UART_DSR)
1093 				port->icount.dsr++;
1094 			if (delta & UART_RI)
1095 				port->icount.rng++;
1096 			if (delta & UART_CD)
1097 				port->icount.dcd++;
1098 
1099 			wake_up_interruptible(&port->port.delta_msr_wait);
1100 		}
1101 
1102 		priv->prev_status = priv->current_status;
1103 	}
1104 	spin_unlock_irqrestore(&priv->lock, flags);
1105 
1106 	/* hangup, as defined in acm.c... this might be a bad place for it
1107 	 * though */
1108 	if (tty && !C_CLOCAL(tty) && !(priv->current_status & UART_CD)) {
1109 		dev_dbg(dev, "%s - calling hangup\n", __func__);
1110 		tty_hangup(tty);
1111 		goto continue_read;
1112 	}
1113 
1114 	/* There is one error bit... I'm assuming it is a parity error
1115 	 * indicator as the generic firmware will set this bit to 1 if a
1116 	 * parity error occurs.
1117 	 * I can not find reference to any other error events. */
1118 	spin_lock_irqsave(&priv->lock, flags);
1119 	if (priv->current_status & CYP_ERROR) {
1120 		spin_unlock_irqrestore(&priv->lock, flags);
1121 		tty_flag = TTY_PARITY;
1122 		dev_dbg(dev, "%s - Parity Error detected\n", __func__);
1123 	} else
1124 		spin_unlock_irqrestore(&priv->lock, flags);
1125 
1126 	/* process read if there is data other than line status */
1127 	if (bytes > i) {
1128 		tty_insert_flip_string_fixed_flag(&port->port, data + i,
1129 				tty_flag, bytes - i);
1130 		tty_flip_buffer_push(&port->port);
1131 	}
1132 
1133 	spin_lock_irqsave(&priv->lock, flags);
1134 	/* control and status byte(s) are also counted */
1135 	priv->bytes_in += bytes;
1136 	spin_unlock_irqrestore(&priv->lock, flags);
1137 
1138 continue_read:
1139 	tty_kref_put(tty);
1140 
1141 	/* Continue trying to always read */
1142 
1143 	if (priv->comm_is_ok) {
1144 		usb_fill_int_urb(port->interrupt_in_urb, port->serial->dev,
1145 				usb_rcvintpipe(port->serial->dev,
1146 					port->interrupt_in_endpointAddress),
1147 				port->interrupt_in_urb->transfer_buffer,
1148 				port->interrupt_in_urb->transfer_buffer_length,
1149 				cypress_read_int_callback, port,
1150 				priv->read_urb_interval);
1151 		result = usb_submit_urb(port->interrupt_in_urb, GFP_ATOMIC);
1152 		if (result && result != -EPERM) {
1153 			dev_err(dev, "%s - failed resubmitting read urb, error %d\n",
1154 				__func__, result);
1155 			cypress_set_dead(port);
1156 		}
1157 	}
1158 } /* cypress_read_int_callback */
1159 
1160 
1161 static void cypress_write_int_callback(struct urb *urb)
1162 {
1163 	struct usb_serial_port *port = urb->context;
1164 	struct cypress_private *priv = usb_get_serial_port_data(port);
1165 	struct device *dev = &urb->dev->dev;
1166 	int status = urb->status;
1167 
1168 	switch (status) {
1169 	case 0:
1170 		/* success */
1171 		break;
1172 	case -ECONNRESET:
1173 	case -ENOENT:
1174 	case -ESHUTDOWN:
1175 		/* this urb is terminated, clean up */
1176 		dev_dbg(dev, "%s - urb shutting down with status: %d\n",
1177 			__func__, status);
1178 		priv->write_urb_in_use = 0;
1179 		return;
1180 	case -EPIPE:
1181 		/* Cannot call usb_clear_halt while in_interrupt */
1182 		fallthrough;
1183 	default:
1184 		dev_err(dev, "%s - unexpected nonzero write status received: %d\n",
1185 			__func__, status);
1186 		cypress_set_dead(port);
1187 		break;
1188 	}
1189 	priv->write_urb_in_use = 0;
1190 
1191 	/* send any buffered data */
1192 	cypress_send(port);
1193 }
1194 
1195 module_usb_serial_driver(serial_drivers, id_table_combined);
1196 
1197 MODULE_AUTHOR(DRIVER_AUTHOR);
1198 MODULE_DESCRIPTION(DRIVER_DESC);
1199 MODULE_LICENSE("GPL");
1200 
1201 module_param(stats, bool, 0644);
1202 MODULE_PARM_DESC(stats, "Enable statistics or not");
1203 module_param(interval, int, 0644);
1204 MODULE_PARM_DESC(interval, "Overrides interrupt interval");
1205 module_param(unstable_bauds, bool, 0644);
1206 MODULE_PARM_DESC(unstable_bauds, "Allow unstable baud rates");
1207