xref: /openbmc/linux/drivers/usb/serial/mct_u232.c (revision bc5aa3a0)
1 /*
2  * MCT (Magic Control Technology Corp.) USB RS232 Converter Driver
3  *
4  *   Copyright (C) 2000 Wolfgang Grandegger (wolfgang@ces.ch)
5  *
6  *   This program is free software; you can redistribute it and/or modify
7  *   it under the terms of the GNU General Public License as published by
8  *   the Free Software Foundation; either version 2 of the License, or
9  *   (at your option) any later version.
10  *
11  * This program is largely derived from the Belkin USB Serial Adapter Driver
12  * (see belkin_sa.[ch]). All of the information about the device was acquired
13  * by using SniffUSB on Windows98. For technical details see mct_u232.h.
14  *
15  * William G. Greathouse and Greg Kroah-Hartman provided great help on how to
16  * do the reverse engineering and how to write a USB serial device driver.
17  *
18  * TO BE DONE, TO BE CHECKED:
19  *   DTR/RTS signal handling may be incomplete or incorrect. I have mainly
20  *   implemented what I have seen with SniffUSB or found in belkin_sa.c.
21  *   For further TODOs check also belkin_sa.c.
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/spinlock.h>
32 #include <linux/uaccess.h>
33 #include <asm/unaligned.h>
34 #include <linux/usb.h>
35 #include <linux/usb/serial.h>
36 #include <linux/serial.h>
37 #include "mct_u232.h"
38 
39 #define DRIVER_AUTHOR "Wolfgang Grandegger <wolfgang@ces.ch>"
40 #define DRIVER_DESC "Magic Control Technology USB-RS232 converter driver"
41 
42 /*
43  * Function prototypes
44  */
45 static int  mct_u232_port_probe(struct usb_serial_port *port);
46 static int  mct_u232_port_remove(struct usb_serial_port *remove);
47 static int  mct_u232_open(struct tty_struct *tty, struct usb_serial_port *port);
48 static void mct_u232_close(struct usb_serial_port *port);
49 static void mct_u232_dtr_rts(struct usb_serial_port *port, int on);
50 static void mct_u232_read_int_callback(struct urb *urb);
51 static void mct_u232_set_termios(struct tty_struct *tty,
52 			struct usb_serial_port *port, struct ktermios *old);
53 static void mct_u232_break_ctl(struct tty_struct *tty, int break_state);
54 static int  mct_u232_tiocmget(struct tty_struct *tty);
55 static int  mct_u232_tiocmset(struct tty_struct *tty,
56 			unsigned int set, unsigned int clear);
57 static void mct_u232_throttle(struct tty_struct *tty);
58 static void mct_u232_unthrottle(struct tty_struct *tty);
59 
60 
61 /*
62  * All of the device info needed for the MCT USB-RS232 converter.
63  */
64 static const struct usb_device_id id_table[] = {
65 	{ USB_DEVICE(MCT_U232_VID, MCT_U232_PID) },
66 	{ USB_DEVICE(MCT_U232_VID, MCT_U232_SITECOM_PID) },
67 	{ USB_DEVICE(MCT_U232_VID, MCT_U232_DU_H3SP_PID) },
68 	{ USB_DEVICE(MCT_U232_BELKIN_F5U109_VID, MCT_U232_BELKIN_F5U109_PID) },
69 	{ }		/* Terminating entry */
70 };
71 MODULE_DEVICE_TABLE(usb, id_table);
72 
73 static struct usb_serial_driver mct_u232_device = {
74 	.driver = {
75 		.owner =	THIS_MODULE,
76 		.name =		"mct_u232",
77 	},
78 	.description =	     "MCT U232",
79 	.id_table =	     id_table,
80 	.num_ports =	     1,
81 	.open =		     mct_u232_open,
82 	.close =	     mct_u232_close,
83 	.dtr_rts =	     mct_u232_dtr_rts,
84 	.throttle =	     mct_u232_throttle,
85 	.unthrottle =	     mct_u232_unthrottle,
86 	.read_int_callback = mct_u232_read_int_callback,
87 	.set_termios =	     mct_u232_set_termios,
88 	.break_ctl =	     mct_u232_break_ctl,
89 	.tiocmget =	     mct_u232_tiocmget,
90 	.tiocmset =	     mct_u232_tiocmset,
91 	.tiocmiwait =        usb_serial_generic_tiocmiwait,
92 	.port_probe =        mct_u232_port_probe,
93 	.port_remove =       mct_u232_port_remove,
94 	.get_icount =        usb_serial_generic_get_icount,
95 };
96 
97 static struct usb_serial_driver * const serial_drivers[] = {
98 	&mct_u232_device, NULL
99 };
100 
101 struct mct_u232_private {
102 	struct urb *read_urb;
103 	spinlock_t lock;
104 	unsigned int	     control_state; /* Modem Line Setting (TIOCM) */
105 	unsigned char        last_lcr;      /* Line Control Register */
106 	unsigned char	     last_lsr;      /* Line Status Register */
107 	unsigned char	     last_msr;      /* Modem Status Register */
108 	unsigned int	     rx_flags;      /* Throttling flags */
109 };
110 
111 #define THROTTLED		0x01
112 
113 /*
114  * Handle vendor specific USB requests
115  */
116 
117 #define WDR_TIMEOUT 5000 /* default urb timeout */
118 
119 /*
120  * Later day 2.6.0-test kernels have new baud rates like B230400 which
121  * we do not know how to support. We ignore them for the moment.
122  */
123 static int mct_u232_calculate_baud_rate(struct usb_serial *serial,
124 					speed_t value, speed_t *result)
125 {
126 	*result = value;
127 
128 	if (le16_to_cpu(serial->dev->descriptor.idProduct) == MCT_U232_SITECOM_PID
129 		|| le16_to_cpu(serial->dev->descriptor.idProduct) == MCT_U232_BELKIN_F5U109_PID) {
130 		switch (value) {
131 		case 300:
132 			return 0x01;
133 		case 600:
134 			return 0x02; /* this one not tested */
135 		case 1200:
136 			return 0x03;
137 		case 2400:
138 			return 0x04;
139 		case 4800:
140 			return 0x06;
141 		case 9600:
142 			return 0x08;
143 		case 19200:
144 			return 0x09;
145 		case 38400:
146 			return 0x0a;
147 		case 57600:
148 			return 0x0b;
149 		case 115200:
150 			return 0x0c;
151 		default:
152 			*result = 9600;
153 			return 0x08;
154 		}
155 	} else {
156 		/* FIXME: Can we use any divider - should we do
157 		   divider = 115200/value;
158 		   real baud = 115200/divider */
159 		switch (value) {
160 		case 300: break;
161 		case 600: break;
162 		case 1200: break;
163 		case 2400: break;
164 		case 4800: break;
165 		case 9600: break;
166 		case 19200: break;
167 		case 38400: break;
168 		case 57600: break;
169 		case 115200: break;
170 		default:
171 			value = 9600;
172 			*result = 9600;
173 		}
174 		return 115200/value;
175 	}
176 }
177 
178 static int mct_u232_set_baud_rate(struct tty_struct *tty,
179 	struct usb_serial *serial, struct usb_serial_port *port, speed_t value)
180 {
181 	unsigned int divisor;
182 	int rc;
183 	unsigned char *buf;
184 	unsigned char cts_enable_byte = 0;
185 	speed_t speed;
186 
187 	buf = kmalloc(MCT_U232_MAX_SIZE, GFP_KERNEL);
188 	if (buf == NULL)
189 		return -ENOMEM;
190 
191 	divisor = mct_u232_calculate_baud_rate(serial, value, &speed);
192 	put_unaligned_le32(cpu_to_le32(divisor), buf);
193 	rc = usb_control_msg(serial->dev, usb_sndctrlpipe(serial->dev, 0),
194 				MCT_U232_SET_BAUD_RATE_REQUEST,
195 				MCT_U232_SET_REQUEST_TYPE,
196 				0, 0, buf, MCT_U232_SET_BAUD_RATE_SIZE,
197 				WDR_TIMEOUT);
198 	if (rc < 0)	/*FIXME: What value speed results */
199 		dev_err(&port->dev, "Set BAUD RATE %d failed (error = %d)\n",
200 			value, rc);
201 	else
202 		tty_encode_baud_rate(tty, speed, speed);
203 	dev_dbg(&port->dev, "set_baud_rate: value: 0x%x, divisor: 0x%x\n", value, divisor);
204 
205 	/* Mimic the MCT-supplied Windows driver (version 1.21P.0104), which
206 	   always sends two extra USB 'device request' messages after the
207 	   'baud rate change' message.  The actual functionality of the
208 	   request codes in these messages is not fully understood but these
209 	   particular codes are never seen in any operation besides a baud
210 	   rate change.  Both of these messages send a single byte of data.
211 	   In the first message, the value of this byte is always zero.
212 
213 	   The second message has been determined experimentally to control
214 	   whether data will be transmitted to a device which is not asserting
215 	   the 'CTS' signal.  If the second message's data byte is zero, data
216 	   will be transmitted even if 'CTS' is not asserted (i.e. no hardware
217 	   flow control).  if the second message's data byte is nonzero (a
218 	   value of 1 is used by this driver), data will not be transmitted to
219 	   a device which is not asserting 'CTS'.
220 	*/
221 
222 	buf[0] = 0;
223 	rc = usb_control_msg(serial->dev, usb_sndctrlpipe(serial->dev, 0),
224 				MCT_U232_SET_UNKNOWN1_REQUEST,
225 				MCT_U232_SET_REQUEST_TYPE,
226 				0, 0, buf, MCT_U232_SET_UNKNOWN1_SIZE,
227 				WDR_TIMEOUT);
228 	if (rc < 0)
229 		dev_err(&port->dev, "Sending USB device request code %d "
230 			"failed (error = %d)\n", MCT_U232_SET_UNKNOWN1_REQUEST,
231 			rc);
232 
233 	if (port && C_CRTSCTS(tty))
234 	   cts_enable_byte = 1;
235 
236 	dev_dbg(&port->dev, "set_baud_rate: send second control message, data = %02X\n",
237 		cts_enable_byte);
238 	buf[0] = cts_enable_byte;
239 	rc = usb_control_msg(serial->dev, usb_sndctrlpipe(serial->dev, 0),
240 			MCT_U232_SET_CTS_REQUEST,
241 			MCT_U232_SET_REQUEST_TYPE,
242 			0, 0, buf, MCT_U232_SET_CTS_SIZE,
243 			WDR_TIMEOUT);
244 	if (rc < 0)
245 		dev_err(&port->dev, "Sending USB device request code %d "
246 			"failed (error = %d)\n", MCT_U232_SET_CTS_REQUEST, rc);
247 
248 	kfree(buf);
249 	return rc;
250 } /* mct_u232_set_baud_rate */
251 
252 static int mct_u232_set_line_ctrl(struct usb_serial_port *port,
253 				  unsigned char lcr)
254 {
255 	int rc;
256 	unsigned char *buf;
257 
258 	buf = kmalloc(MCT_U232_MAX_SIZE, GFP_KERNEL);
259 	if (buf == NULL)
260 		return -ENOMEM;
261 
262 	buf[0] = lcr;
263 	rc = usb_control_msg(port->serial->dev, usb_sndctrlpipe(port->serial->dev, 0),
264 			MCT_U232_SET_LINE_CTRL_REQUEST,
265 			MCT_U232_SET_REQUEST_TYPE,
266 			0, 0, buf, MCT_U232_SET_LINE_CTRL_SIZE,
267 			WDR_TIMEOUT);
268 	if (rc < 0)
269 		dev_err(&port->dev, "Set LINE CTRL 0x%x failed (error = %d)\n", lcr, rc);
270 	dev_dbg(&port->dev, "set_line_ctrl: 0x%x\n", lcr);
271 	kfree(buf);
272 	return rc;
273 } /* mct_u232_set_line_ctrl */
274 
275 static int mct_u232_set_modem_ctrl(struct usb_serial_port *port,
276 				   unsigned int control_state)
277 {
278 	int rc;
279 	unsigned char mcr;
280 	unsigned char *buf;
281 
282 	buf = kmalloc(MCT_U232_MAX_SIZE, GFP_KERNEL);
283 	if (buf == NULL)
284 		return -ENOMEM;
285 
286 	mcr = MCT_U232_MCR_NONE;
287 	if (control_state & TIOCM_DTR)
288 		mcr |= MCT_U232_MCR_DTR;
289 	if (control_state & TIOCM_RTS)
290 		mcr |= MCT_U232_MCR_RTS;
291 
292 	buf[0] = mcr;
293 	rc = usb_control_msg(port->serial->dev, usb_sndctrlpipe(port->serial->dev, 0),
294 			MCT_U232_SET_MODEM_CTRL_REQUEST,
295 			MCT_U232_SET_REQUEST_TYPE,
296 			0, 0, buf, MCT_U232_SET_MODEM_CTRL_SIZE,
297 			WDR_TIMEOUT);
298 	kfree(buf);
299 
300 	dev_dbg(&port->dev, "set_modem_ctrl: state=0x%x ==> mcr=0x%x\n", control_state, mcr);
301 
302 	if (rc < 0) {
303 		dev_err(&port->dev, "Set MODEM CTRL 0x%x failed (error = %d)\n", mcr, rc);
304 		return rc;
305 	}
306 	return 0;
307 } /* mct_u232_set_modem_ctrl */
308 
309 static int mct_u232_get_modem_stat(struct usb_serial_port *port,
310 				   unsigned char *msr)
311 {
312 	int rc;
313 	unsigned char *buf;
314 
315 	buf = kmalloc(MCT_U232_MAX_SIZE, GFP_KERNEL);
316 	if (buf == NULL) {
317 		*msr = 0;
318 		return -ENOMEM;
319 	}
320 	rc = usb_control_msg(port->serial->dev, usb_rcvctrlpipe(port->serial->dev, 0),
321 			MCT_U232_GET_MODEM_STAT_REQUEST,
322 			MCT_U232_GET_REQUEST_TYPE,
323 			0, 0, buf, MCT_U232_GET_MODEM_STAT_SIZE,
324 			WDR_TIMEOUT);
325 	if (rc < 0) {
326 		dev_err(&port->dev, "Get MODEM STATus failed (error = %d)\n", rc);
327 		*msr = 0;
328 	} else {
329 		*msr = buf[0];
330 	}
331 	dev_dbg(&port->dev, "get_modem_stat: 0x%x\n", *msr);
332 	kfree(buf);
333 	return rc;
334 } /* mct_u232_get_modem_stat */
335 
336 static void mct_u232_msr_to_icount(struct async_icount *icount,
337 						unsigned char msr)
338 {
339 	/* Translate Control Line states */
340 	if (msr & MCT_U232_MSR_DDSR)
341 		icount->dsr++;
342 	if (msr & MCT_U232_MSR_DCTS)
343 		icount->cts++;
344 	if (msr & MCT_U232_MSR_DRI)
345 		icount->rng++;
346 	if (msr & MCT_U232_MSR_DCD)
347 		icount->dcd++;
348 } /* mct_u232_msr_to_icount */
349 
350 static void mct_u232_msr_to_state(struct usb_serial_port *port,
351 				  unsigned int *control_state, unsigned char msr)
352 {
353 	/* Translate Control Line states */
354 	if (msr & MCT_U232_MSR_DSR)
355 		*control_state |=  TIOCM_DSR;
356 	else
357 		*control_state &= ~TIOCM_DSR;
358 	if (msr & MCT_U232_MSR_CTS)
359 		*control_state |=  TIOCM_CTS;
360 	else
361 		*control_state &= ~TIOCM_CTS;
362 	if (msr & MCT_U232_MSR_RI)
363 		*control_state |=  TIOCM_RI;
364 	else
365 		*control_state &= ~TIOCM_RI;
366 	if (msr & MCT_U232_MSR_CD)
367 		*control_state |=  TIOCM_CD;
368 	else
369 		*control_state &= ~TIOCM_CD;
370 	dev_dbg(&port->dev, "msr_to_state: msr=0x%x ==> state=0x%x\n", msr, *control_state);
371 } /* mct_u232_msr_to_state */
372 
373 /*
374  * Driver's tty interface functions
375  */
376 
377 static int mct_u232_port_probe(struct usb_serial_port *port)
378 {
379 	struct usb_serial *serial = port->serial;
380 	struct mct_u232_private *priv;
381 
382 	/* check first to simplify error handling */
383 	if (!serial->port[1] || !serial->port[1]->interrupt_in_urb) {
384 		dev_err(&port->dev, "expected endpoint missing\n");
385 		return -ENODEV;
386 	}
387 
388 	priv = kzalloc(sizeof(*priv), GFP_KERNEL);
389 	if (!priv)
390 		return -ENOMEM;
391 
392 	/* Use second interrupt-in endpoint for reading. */
393 	priv->read_urb = serial->port[1]->interrupt_in_urb;
394 	priv->read_urb->context = port;
395 
396 	spin_lock_init(&priv->lock);
397 
398 	usb_set_serial_port_data(port, priv);
399 
400 	return 0;
401 }
402 
403 static int mct_u232_port_remove(struct usb_serial_port *port)
404 {
405 	struct mct_u232_private *priv;
406 
407 	priv = usb_get_serial_port_data(port);
408 	kfree(priv);
409 
410 	return 0;
411 }
412 
413 static int  mct_u232_open(struct tty_struct *tty, struct usb_serial_port *port)
414 {
415 	struct usb_serial *serial = port->serial;
416 	struct mct_u232_private *priv = usb_get_serial_port_data(port);
417 	int retval = 0;
418 	unsigned int control_state;
419 	unsigned long flags;
420 	unsigned char last_lcr;
421 	unsigned char last_msr;
422 
423 	/* Compensate for a hardware bug: although the Sitecom U232-P25
424 	 * device reports a maximum output packet size of 32 bytes,
425 	 * it seems to be able to accept only 16 bytes (and that's what
426 	 * SniffUSB says too...)
427 	 */
428 	if (le16_to_cpu(serial->dev->descriptor.idProduct)
429 						== MCT_U232_SITECOM_PID)
430 		port->bulk_out_size = 16;
431 
432 	/* Do a defined restart: the normal serial device seems to
433 	 * always turn on DTR and RTS here, so do the same. I'm not
434 	 * sure if this is really necessary. But it should not harm
435 	 * either.
436 	 */
437 	spin_lock_irqsave(&priv->lock, flags);
438 	if (tty && C_BAUD(tty))
439 		priv->control_state = TIOCM_DTR | TIOCM_RTS;
440 	else
441 		priv->control_state = 0;
442 
443 	priv->last_lcr = (MCT_U232_DATA_BITS_8 |
444 			  MCT_U232_PARITY_NONE |
445 			  MCT_U232_STOP_BITS_1);
446 	control_state = priv->control_state;
447 	last_lcr = priv->last_lcr;
448 	spin_unlock_irqrestore(&priv->lock, flags);
449 	mct_u232_set_modem_ctrl(port, control_state);
450 	mct_u232_set_line_ctrl(port, last_lcr);
451 
452 	/* Read modem status and update control state */
453 	mct_u232_get_modem_stat(port, &last_msr);
454 	spin_lock_irqsave(&priv->lock, flags);
455 	priv->last_msr = last_msr;
456 	mct_u232_msr_to_state(port, &priv->control_state, priv->last_msr);
457 	spin_unlock_irqrestore(&priv->lock, flags);
458 
459 	retval = usb_submit_urb(priv->read_urb, GFP_KERNEL);
460 	if (retval) {
461 		dev_err(&port->dev,
462 			"usb_submit_urb(read) failed pipe 0x%x err %d\n",
463 			port->read_urb->pipe, retval);
464 		goto error;
465 	}
466 
467 	retval = usb_submit_urb(port->interrupt_in_urb, GFP_KERNEL);
468 	if (retval) {
469 		usb_kill_urb(priv->read_urb);
470 		dev_err(&port->dev,
471 			"usb_submit_urb(read int) failed pipe 0x%x err %d",
472 			port->interrupt_in_urb->pipe, retval);
473 		goto error;
474 	}
475 	return 0;
476 
477 error:
478 	return retval;
479 } /* mct_u232_open */
480 
481 static void mct_u232_dtr_rts(struct usb_serial_port *port, int on)
482 {
483 	unsigned int control_state;
484 	struct mct_u232_private *priv = usb_get_serial_port_data(port);
485 
486 	spin_lock_irq(&priv->lock);
487 	if (on)
488 		priv->control_state |= TIOCM_DTR | TIOCM_RTS;
489 	else
490 		priv->control_state &= ~(TIOCM_DTR | TIOCM_RTS);
491 	control_state = priv->control_state;
492 	spin_unlock_irq(&priv->lock);
493 
494 	mct_u232_set_modem_ctrl(port, control_state);
495 }
496 
497 static void mct_u232_close(struct usb_serial_port *port)
498 {
499 	struct mct_u232_private *priv = usb_get_serial_port_data(port);
500 
501 	usb_kill_urb(priv->read_urb);
502 	usb_kill_urb(port->interrupt_in_urb);
503 
504 	usb_serial_generic_close(port);
505 } /* mct_u232_close */
506 
507 
508 static void mct_u232_read_int_callback(struct urb *urb)
509 {
510 	struct usb_serial_port *port = urb->context;
511 	struct mct_u232_private *priv = usb_get_serial_port_data(port);
512 	unsigned char *data = urb->transfer_buffer;
513 	int retval;
514 	int status = urb->status;
515 	unsigned long flags;
516 
517 	switch (status) {
518 	case 0:
519 		/* success */
520 		break;
521 	case -ECONNRESET:
522 	case -ENOENT:
523 	case -ESHUTDOWN:
524 		/* this urb is terminated, clean up */
525 		dev_dbg(&port->dev, "%s - urb shutting down with status: %d\n",
526 			__func__, status);
527 		return;
528 	default:
529 		dev_dbg(&port->dev, "%s - nonzero urb status received: %d\n",
530 			__func__, status);
531 		goto exit;
532 	}
533 
534 	usb_serial_debug_data(&port->dev, __func__, urb->actual_length, data);
535 
536 	/*
537 	 * Work-a-round: handle the 'usual' bulk-in pipe here
538 	 */
539 	if (urb->transfer_buffer_length > 2) {
540 		if (urb->actual_length) {
541 			tty_insert_flip_string(&port->port, data,
542 					urb->actual_length);
543 			tty_flip_buffer_push(&port->port);
544 		}
545 		goto exit;
546 	}
547 
548 	/*
549 	 * The interrupt-in pipe signals exceptional conditions (modem line
550 	 * signal changes and errors). data[0] holds MSR, data[1] holds LSR.
551 	 */
552 	spin_lock_irqsave(&priv->lock, flags);
553 	priv->last_msr = data[MCT_U232_MSR_INDEX];
554 
555 	/* Record Control Line states */
556 	mct_u232_msr_to_state(port, &priv->control_state, priv->last_msr);
557 
558 	mct_u232_msr_to_icount(&port->icount, priv->last_msr);
559 
560 #if 0
561 	/* Not yet handled. See belkin_sa.c for further information */
562 	/* Now to report any errors */
563 	priv->last_lsr = data[MCT_U232_LSR_INDEX];
564 	/*
565 	 * fill in the flip buffer here, but I do not know the relation
566 	 * to the current/next receive buffer or characters.  I need
567 	 * to look in to this before committing any code.
568 	 */
569 	if (priv->last_lsr & MCT_U232_LSR_ERR) {
570 		tty = tty_port_tty_get(&port->port);
571 		/* Overrun Error */
572 		if (priv->last_lsr & MCT_U232_LSR_OE) {
573 		}
574 		/* Parity Error */
575 		if (priv->last_lsr & MCT_U232_LSR_PE) {
576 		}
577 		/* Framing Error */
578 		if (priv->last_lsr & MCT_U232_LSR_FE) {
579 		}
580 		/* Break Indicator */
581 		if (priv->last_lsr & MCT_U232_LSR_BI) {
582 		}
583 		tty_kref_put(tty);
584 	}
585 #endif
586 	wake_up_interruptible(&port->port.delta_msr_wait);
587 	spin_unlock_irqrestore(&priv->lock, flags);
588 exit:
589 	retval = usb_submit_urb(urb, GFP_ATOMIC);
590 	if (retval)
591 		dev_err(&port->dev,
592 			"%s - usb_submit_urb failed with result %d\n",
593 			__func__, retval);
594 } /* mct_u232_read_int_callback */
595 
596 static void mct_u232_set_termios(struct tty_struct *tty,
597 				 struct usb_serial_port *port,
598 				 struct ktermios *old_termios)
599 {
600 	struct usb_serial *serial = port->serial;
601 	struct mct_u232_private *priv = usb_get_serial_port_data(port);
602 	struct ktermios *termios = &tty->termios;
603 	unsigned int cflag = termios->c_cflag;
604 	unsigned int old_cflag = old_termios->c_cflag;
605 	unsigned long flags;
606 	unsigned int control_state;
607 	unsigned char last_lcr;
608 
609 	/* get a local copy of the current port settings */
610 	spin_lock_irqsave(&priv->lock, flags);
611 	control_state = priv->control_state;
612 	spin_unlock_irqrestore(&priv->lock, flags);
613 	last_lcr = 0;
614 
615 	/*
616 	 * Update baud rate.
617 	 * Do not attempt to cache old rates and skip settings,
618 	 * disconnects screw such tricks up completely.
619 	 * Premature optimization is the root of all evil.
620 	 */
621 
622 	/* reassert DTR and RTS on transition from B0 */
623 	if ((old_cflag & CBAUD) == B0) {
624 		dev_dbg(&port->dev, "%s: baud was B0\n", __func__);
625 		control_state |= TIOCM_DTR | TIOCM_RTS;
626 		mct_u232_set_modem_ctrl(port, control_state);
627 	}
628 
629 	mct_u232_set_baud_rate(tty, serial, port, tty_get_baud_rate(tty));
630 
631 	if ((cflag & CBAUD) == B0) {
632 		dev_dbg(&port->dev, "%s: baud is B0\n", __func__);
633 		/* Drop RTS and DTR */
634 		control_state &= ~(TIOCM_DTR | TIOCM_RTS);
635 		mct_u232_set_modem_ctrl(port, control_state);
636 	}
637 
638 	/*
639 	 * Update line control register (LCR)
640 	 */
641 
642 	/* set the parity */
643 	if (cflag & PARENB)
644 		last_lcr |= (cflag & PARODD) ?
645 			MCT_U232_PARITY_ODD : MCT_U232_PARITY_EVEN;
646 	else
647 		last_lcr |= MCT_U232_PARITY_NONE;
648 
649 	/* set the number of data bits */
650 	switch (cflag & CSIZE) {
651 	case CS5:
652 		last_lcr |= MCT_U232_DATA_BITS_5; break;
653 	case CS6:
654 		last_lcr |= MCT_U232_DATA_BITS_6; break;
655 	case CS7:
656 		last_lcr |= MCT_U232_DATA_BITS_7; break;
657 	case CS8:
658 		last_lcr |= MCT_U232_DATA_BITS_8; break;
659 	default:
660 		dev_err(&port->dev,
661 			"CSIZE was not CS5-CS8, using default of 8\n");
662 		last_lcr |= MCT_U232_DATA_BITS_8;
663 		break;
664 	}
665 
666 	termios->c_cflag &= ~CMSPAR;
667 
668 	/* set the number of stop bits */
669 	last_lcr |= (cflag & CSTOPB) ?
670 		MCT_U232_STOP_BITS_2 : MCT_U232_STOP_BITS_1;
671 
672 	mct_u232_set_line_ctrl(port, last_lcr);
673 
674 	/* save off the modified port settings */
675 	spin_lock_irqsave(&priv->lock, flags);
676 	priv->control_state = control_state;
677 	priv->last_lcr = last_lcr;
678 	spin_unlock_irqrestore(&priv->lock, flags);
679 } /* mct_u232_set_termios */
680 
681 static void mct_u232_break_ctl(struct tty_struct *tty, int break_state)
682 {
683 	struct usb_serial_port *port = tty->driver_data;
684 	struct mct_u232_private *priv = usb_get_serial_port_data(port);
685 	unsigned char lcr;
686 	unsigned long flags;
687 
688 	spin_lock_irqsave(&priv->lock, flags);
689 	lcr = priv->last_lcr;
690 
691 	if (break_state)
692 		lcr |= MCT_U232_SET_BREAK;
693 	spin_unlock_irqrestore(&priv->lock, flags);
694 
695 	mct_u232_set_line_ctrl(port, lcr);
696 } /* mct_u232_break_ctl */
697 
698 
699 static int mct_u232_tiocmget(struct tty_struct *tty)
700 {
701 	struct usb_serial_port *port = tty->driver_data;
702 	struct mct_u232_private *priv = usb_get_serial_port_data(port);
703 	unsigned int control_state;
704 	unsigned long flags;
705 
706 	spin_lock_irqsave(&priv->lock, flags);
707 	control_state = priv->control_state;
708 	spin_unlock_irqrestore(&priv->lock, flags);
709 
710 	return control_state;
711 }
712 
713 static int mct_u232_tiocmset(struct tty_struct *tty,
714 			      unsigned int set, unsigned int clear)
715 {
716 	struct usb_serial_port *port = tty->driver_data;
717 	struct mct_u232_private *priv = usb_get_serial_port_data(port);
718 	unsigned int control_state;
719 	unsigned long flags;
720 
721 	spin_lock_irqsave(&priv->lock, flags);
722 	control_state = priv->control_state;
723 
724 	if (set & TIOCM_RTS)
725 		control_state |= TIOCM_RTS;
726 	if (set & TIOCM_DTR)
727 		control_state |= TIOCM_DTR;
728 	if (clear & TIOCM_RTS)
729 		control_state &= ~TIOCM_RTS;
730 	if (clear & TIOCM_DTR)
731 		control_state &= ~TIOCM_DTR;
732 
733 	priv->control_state = control_state;
734 	spin_unlock_irqrestore(&priv->lock, flags);
735 	return mct_u232_set_modem_ctrl(port, control_state);
736 }
737 
738 static void mct_u232_throttle(struct tty_struct *tty)
739 {
740 	struct usb_serial_port *port = tty->driver_data;
741 	struct mct_u232_private *priv = usb_get_serial_port_data(port);
742 	unsigned int control_state;
743 
744 	spin_lock_irq(&priv->lock);
745 	priv->rx_flags |= THROTTLED;
746 	if (C_CRTSCTS(tty)) {
747 		priv->control_state &= ~TIOCM_RTS;
748 		control_state = priv->control_state;
749 		spin_unlock_irq(&priv->lock);
750 		mct_u232_set_modem_ctrl(port, control_state);
751 	} else {
752 		spin_unlock_irq(&priv->lock);
753 	}
754 }
755 
756 static void mct_u232_unthrottle(struct tty_struct *tty)
757 {
758 	struct usb_serial_port *port = tty->driver_data;
759 	struct mct_u232_private *priv = usb_get_serial_port_data(port);
760 	unsigned int control_state;
761 
762 	spin_lock_irq(&priv->lock);
763 	if ((priv->rx_flags & THROTTLED) && C_CRTSCTS(tty)) {
764 		priv->rx_flags &= ~THROTTLED;
765 		priv->control_state |= TIOCM_RTS;
766 		control_state = priv->control_state;
767 		spin_unlock_irq(&priv->lock);
768 		mct_u232_set_modem_ctrl(port, control_state);
769 	} else {
770 		spin_unlock_irq(&priv->lock);
771 	}
772 }
773 
774 module_usb_serial_driver(serial_drivers, id_table);
775 
776 MODULE_AUTHOR(DRIVER_AUTHOR);
777 MODULE_DESCRIPTION(DRIVER_DESC);
778 MODULE_LICENSE("GPL");
779