xref: /linux/drivers/usb/serial/kl5kusb105.c (revision b889fcf63cb62e7fdb7816565e28f44dbe4a76a5)
1 /*
2  * KLSI KL5KUSB105 chip RS232 converter driver
3  *
4  *   Copyright (C) 2010 Johan Hovold <jhovold@gmail.com>
5  *   Copyright (C) 2001 Utz-Uwe Haus <haus@uuhaus.de>
6  *
7  *   This program is free software; you can redistribute it and/or modify
8  *   it under the terms of the GNU General Public License as published by
9  *   the Free Software Foundation; either version 2 of the License, or
10  *   (at your option) any later version.
11  *
12  * All information about the device was acquired using SniffUSB ans snoopUSB
13  * on Windows98.
14  * It was written out of frustration with the PalmConnect USB Serial adapter
15  * sold by Palm Inc.
16  * Neither Palm, nor their contractor (MCCI) or their supplier (KLSI) provided
17  * information that was not already available.
18  *
19  * It seems that KLSI bought some silicon-design information from ScanLogic,
20  * whose SL11R processor is at the core of the KL5KUSB chipset from KLSI.
21  * KLSI has firmware available for their devices; it is probable that the
22  * firmware differs from that used by KLSI in their products. If you have an
23  * original KLSI device and can provide some information on it, I would be
24  * most interested in adding support for it here. If you have any information
25  * on the protocol used (or find errors in my reverse-engineered stuff), please
26  * let me know.
27  *
28  * The code was only tested with a PalmConnect USB adapter; if you
29  * are adventurous, try it with any KLSI-based device and let me know how it
30  * breaks so that I can fix it!
31  */
32 
33 /* TODO:
34  *	check modem line signals
35  *	implement handshaking or decide that we do not support it
36  */
37 
38 #include <linux/kernel.h>
39 #include <linux/errno.h>
40 #include <linux/init.h>
41 #include <linux/slab.h>
42 #include <linux/tty.h>
43 #include <linux/tty_driver.h>
44 #include <linux/tty_flip.h>
45 #include <linux/module.h>
46 #include <linux/uaccess.h>
47 #include <asm/unaligned.h>
48 #include <linux/usb.h>
49 #include <linux/usb/serial.h>
50 #include "kl5kusb105.h"
51 
52 #define DRIVER_AUTHOR "Utz-Uwe Haus <haus@uuhaus.de>, Johan Hovold <jhovold@gmail.com>"
53 #define DRIVER_DESC "KLSI KL5KUSB105 chipset USB->Serial Converter driver"
54 
55 
56 /*
57  * Function prototypes
58  */
59 static int klsi_105_port_probe(struct usb_serial_port *port);
60 static int klsi_105_port_remove(struct usb_serial_port *port);
61 static int  klsi_105_open(struct tty_struct *tty, struct usb_serial_port *port);
62 static void klsi_105_close(struct usb_serial_port *port);
63 static void klsi_105_set_termios(struct tty_struct *tty,
64 			struct usb_serial_port *port, struct ktermios *old);
65 static int  klsi_105_tiocmget(struct tty_struct *tty);
66 static int  klsi_105_tiocmset(struct tty_struct *tty,
67 			unsigned int set, unsigned int clear);
68 static void klsi_105_process_read_urb(struct urb *urb);
69 static int klsi_105_prepare_write_buffer(struct usb_serial_port *port,
70 						void *dest, size_t size);
71 
72 /*
73  * All of the device info needed for the KLSI converters.
74  */
75 static const struct usb_device_id id_table[] = {
76 	{ USB_DEVICE(PALMCONNECT_VID, PALMCONNECT_PID) },
77 	{ USB_DEVICE(KLSI_VID, KLSI_KL5KUSB105D_PID) },
78 	{ }		/* Terminating entry */
79 };
80 
81 MODULE_DEVICE_TABLE(usb, id_table);
82 
83 static struct usb_serial_driver kl5kusb105d_device = {
84 	.driver = {
85 		.owner =	THIS_MODULE,
86 		.name =		"kl5kusb105d",
87 	},
88 	.description =		"KL5KUSB105D / PalmConnect",
89 	.id_table =		id_table,
90 	.num_ports =		1,
91 	.bulk_out_size =	64,
92 	.open =			klsi_105_open,
93 	.close =		klsi_105_close,
94 	.set_termios =		klsi_105_set_termios,
95 	/*.break_ctl =		klsi_105_break_ctl,*/
96 	.tiocmget =		klsi_105_tiocmget,
97 	.tiocmset =		klsi_105_tiocmset,
98 	.port_probe =		klsi_105_port_probe,
99 	.port_remove =		klsi_105_port_remove,
100 	.throttle =		usb_serial_generic_throttle,
101 	.unthrottle =		usb_serial_generic_unthrottle,
102 	.process_read_urb =	klsi_105_process_read_urb,
103 	.prepare_write_buffer =	klsi_105_prepare_write_buffer,
104 };
105 
106 static struct usb_serial_driver * const serial_drivers[] = {
107 	&kl5kusb105d_device, NULL
108 };
109 
110 struct klsi_105_port_settings {
111 	__u8	pktlen;		/* always 5, it seems */
112 	__u8	baudrate;
113 	__u8	databits;
114 	__u8	unknown1;
115 	__u8	unknown2;
116 } __attribute__ ((packed));
117 
118 struct klsi_105_private {
119 	struct klsi_105_port_settings	cfg;
120 	struct ktermios			termios;
121 	unsigned long			line_state; /* modem line settings */
122 	spinlock_t			lock;
123 };
124 
125 
126 /*
127  * Handle vendor specific USB requests
128  */
129 
130 
131 #define KLSI_TIMEOUT	 5000 /* default urb timeout */
132 
133 static int klsi_105_chg_port_settings(struct usb_serial_port *port,
134 				      struct klsi_105_port_settings *settings)
135 {
136 	int rc;
137 
138 	rc = usb_control_msg(port->serial->dev,
139 			usb_sndctrlpipe(port->serial->dev, 0),
140 			KL5KUSB105A_SIO_SET_DATA,
141 			USB_TYPE_VENDOR | USB_DIR_OUT | USB_RECIP_INTERFACE,
142 			0, /* value */
143 			0, /* index */
144 			settings,
145 			sizeof(struct klsi_105_port_settings),
146 			KLSI_TIMEOUT);
147 	if (rc < 0)
148 		dev_err(&port->dev,
149 			"Change port settings failed (error = %d)\n", rc);
150 	dev_info(&port->serial->dev->dev,
151 		 "%d byte block, baudrate %x, databits %d, u1 %d, u2 %d\n",
152 		 settings->pktlen, settings->baudrate, settings->databits,
153 		 settings->unknown1, settings->unknown2);
154 	return rc;
155 }
156 
157 /* translate a 16-bit status value from the device to linux's TIO bits */
158 static unsigned long klsi_105_status2linestate(const __u16 status)
159 {
160 	unsigned long res = 0;
161 
162 	res =   ((status & KL5KUSB105A_DSR) ? TIOCM_DSR : 0)
163 	      | ((status & KL5KUSB105A_CTS) ? TIOCM_CTS : 0)
164 	      ;
165 
166 	return res;
167 }
168 
169 /*
170  * Read line control via vendor command and return result through
171  * *line_state_p
172  */
173 /* It seems that the status buffer has always only 2 bytes length */
174 #define KLSI_STATUSBUF_LEN	2
175 static int klsi_105_get_line_state(struct usb_serial_port *port,
176 				   unsigned long *line_state_p)
177 {
178 	int rc;
179 	u8 *status_buf;
180 	__u16 status;
181 
182 	dev_info(&port->serial->dev->dev, "sending SIO Poll request\n");
183 
184 	status_buf = kmalloc(KLSI_STATUSBUF_LEN, GFP_KERNEL);
185 	if (!status_buf) {
186 		dev_err(&port->dev, "%s - out of memory for status buffer.\n",
187 				__func__);
188 		return -ENOMEM;
189 	}
190 	status_buf[0] = 0xff;
191 	status_buf[1] = 0xff;
192 	rc = usb_control_msg(port->serial->dev,
193 			     usb_rcvctrlpipe(port->serial->dev, 0),
194 			     KL5KUSB105A_SIO_POLL,
195 			     USB_TYPE_VENDOR | USB_DIR_IN,
196 			     0, /* value */
197 			     0, /* index */
198 			     status_buf, KLSI_STATUSBUF_LEN,
199 			     10000
200 			     );
201 	if (rc < 0)
202 		dev_err(&port->dev, "Reading line status failed (error = %d)\n",
203 			rc);
204 	else {
205 		status = get_unaligned_le16(status_buf);
206 
207 		dev_info(&port->serial->dev->dev, "read status %x %x",
208 			 status_buf[0], status_buf[1]);
209 
210 		*line_state_p = klsi_105_status2linestate(status);
211 	}
212 
213 	kfree(status_buf);
214 	return rc;
215 }
216 
217 
218 /*
219  * Driver's tty interface functions
220  */
221 
222 static int klsi_105_port_probe(struct usb_serial_port *port)
223 {
224 	struct klsi_105_private *priv;
225 
226 	priv = kmalloc(sizeof(*priv), GFP_KERNEL);
227 	if (!priv)
228 		return -ENOMEM;
229 
230 	/* set initial values for control structures */
231 	priv->cfg.pktlen    = 5;
232 	priv->cfg.baudrate  = kl5kusb105a_sio_b9600;
233 	priv->cfg.databits  = kl5kusb105a_dtb_8;
234 	priv->cfg.unknown1  = 0;
235 	priv->cfg.unknown2  = 1;
236 
237 	priv->line_state    = 0;
238 
239 	spin_lock_init(&priv->lock);
240 
241 	/* priv->termios is left uninitialized until port opening */
242 
243 	usb_set_serial_port_data(port, priv);
244 
245 	return 0;
246 }
247 
248 static int klsi_105_port_remove(struct usb_serial_port *port)
249 {
250 	struct klsi_105_private *priv;
251 
252 	priv = usb_get_serial_port_data(port);
253 	kfree(priv);
254 
255 	return 0;
256 }
257 
258 static int  klsi_105_open(struct tty_struct *tty, struct usb_serial_port *port)
259 {
260 	struct klsi_105_private *priv = usb_get_serial_port_data(port);
261 	int retval = 0;
262 	int rc;
263 	int i;
264 	unsigned long line_state;
265 	struct klsi_105_port_settings *cfg;
266 	unsigned long flags;
267 
268 	/* Do a defined restart:
269 	 * Set up sane default baud rate and send the 'READ_ON'
270 	 * vendor command.
271 	 * FIXME: set modem line control (how?)
272 	 * Then read the modem line control and store values in
273 	 * priv->line_state.
274 	 */
275 	cfg = kmalloc(sizeof(*cfg), GFP_KERNEL);
276 	if (!cfg) {
277 		dev_err(&port->dev, "%s - out of memory for config buffer.\n",
278 				__func__);
279 		return -ENOMEM;
280 	}
281 	cfg->pktlen   = 5;
282 	cfg->baudrate = kl5kusb105a_sio_b9600;
283 	cfg->databits = kl5kusb105a_dtb_8;
284 	cfg->unknown1 = 0;
285 	cfg->unknown2 = 1;
286 	klsi_105_chg_port_settings(port, cfg);
287 
288 	/* set up termios structure */
289 	spin_lock_irqsave(&priv->lock, flags);
290 	priv->termios.c_iflag = tty->termios.c_iflag;
291 	priv->termios.c_oflag = tty->termios.c_oflag;
292 	priv->termios.c_cflag = tty->termios.c_cflag;
293 	priv->termios.c_lflag = tty->termios.c_lflag;
294 	for (i = 0; i < NCCS; i++)
295 		priv->termios.c_cc[i] = tty->termios.c_cc[i];
296 	priv->cfg.pktlen   = cfg->pktlen;
297 	priv->cfg.baudrate = cfg->baudrate;
298 	priv->cfg.databits = cfg->databits;
299 	priv->cfg.unknown1 = cfg->unknown1;
300 	priv->cfg.unknown2 = cfg->unknown2;
301 	spin_unlock_irqrestore(&priv->lock, flags);
302 
303 	/* READ_ON and urb submission */
304 	rc = usb_serial_generic_open(tty, port);
305 	if (rc) {
306 		retval = rc;
307 		goto exit;
308 	}
309 
310 	rc = usb_control_msg(port->serial->dev,
311 			     usb_sndctrlpipe(port->serial->dev, 0),
312 			     KL5KUSB105A_SIO_CONFIGURE,
313 			     USB_TYPE_VENDOR|USB_DIR_OUT|USB_RECIP_INTERFACE,
314 			     KL5KUSB105A_SIO_CONFIGURE_READ_ON,
315 			     0, /* index */
316 			     NULL,
317 			     0,
318 			     KLSI_TIMEOUT);
319 	if (rc < 0) {
320 		dev_err(&port->dev, "Enabling read failed (error = %d)\n", rc);
321 		retval = rc;
322 	} else
323 		dev_dbg(&port->dev, "%s - enabled reading\n", __func__);
324 
325 	rc = klsi_105_get_line_state(port, &line_state);
326 	if (rc >= 0) {
327 		spin_lock_irqsave(&priv->lock, flags);
328 		priv->line_state = line_state;
329 		spin_unlock_irqrestore(&priv->lock, flags);
330 		dev_dbg(&port->dev, "%s - read line state 0x%lx\n", __func__, line_state);
331 		retval = 0;
332 	} else
333 		retval = rc;
334 
335 exit:
336 	kfree(cfg);
337 	return retval;
338 }
339 
340 static void klsi_105_close(struct usb_serial_port *port)
341 {
342 	int rc;
343 
344 	mutex_lock(&port->serial->disc_mutex);
345 	if (!port->serial->disconnected) {
346 		/* send READ_OFF */
347 		rc = usb_control_msg(port->serial->dev,
348 				     usb_sndctrlpipe(port->serial->dev, 0),
349 				     KL5KUSB105A_SIO_CONFIGURE,
350 				     USB_TYPE_VENDOR | USB_DIR_OUT,
351 				     KL5KUSB105A_SIO_CONFIGURE_READ_OFF,
352 				     0, /* index */
353 				     NULL, 0,
354 				     KLSI_TIMEOUT);
355 		if (rc < 0)
356 			dev_err(&port->dev,
357 				"Disabling read failed (error = %d)\n", rc);
358 	}
359 	mutex_unlock(&port->serial->disc_mutex);
360 
361 	/* shutdown our bulk reads and writes */
362 	usb_serial_generic_close(port);
363 
364 	/* wgg - do I need this? I think so. */
365 	usb_kill_urb(port->interrupt_in_urb);
366 }
367 
368 /* We need to write a complete 64-byte data block and encode the
369  * number actually sent in the first double-byte, LSB-order. That
370  * leaves at most 62 bytes of payload.
371  */
372 #define KLSI_HDR_LEN		2
373 static int klsi_105_prepare_write_buffer(struct usb_serial_port *port,
374 						void *dest, size_t size)
375 {
376 	unsigned char *buf = dest;
377 	int count;
378 
379 	count = kfifo_out_locked(&port->write_fifo, buf + KLSI_HDR_LEN, size,
380 								&port->lock);
381 	put_unaligned_le16(count, buf);
382 
383 	return count + KLSI_HDR_LEN;
384 }
385 
386 /* The data received is preceded by a length double-byte in LSB-first order.
387  */
388 static void klsi_105_process_read_urb(struct urb *urb)
389 {
390 	struct usb_serial_port *port = urb->context;
391 	unsigned char *data = urb->transfer_buffer;
392 	struct tty_struct *tty;
393 	unsigned len;
394 
395 	/* empty urbs seem to happen, we ignore them */
396 	if (!urb->actual_length)
397 		return;
398 
399 	if (urb->actual_length <= KLSI_HDR_LEN) {
400 		dev_dbg(&port->dev, "%s - malformed packet\n", __func__);
401 		return;
402 	}
403 
404 	tty = tty_port_tty_get(&port->port);
405 	if (!tty)
406 		return;
407 
408 	len = get_unaligned_le16(data);
409 	if (len > urb->actual_length - KLSI_HDR_LEN) {
410 		dev_dbg(&port->dev, "%s - packet length mismatch\n", __func__);
411 		len = urb->actual_length - KLSI_HDR_LEN;
412 	}
413 
414 	tty_insert_flip_string(tty, data + KLSI_HDR_LEN, len);
415 	tty_flip_buffer_push(tty);
416 	tty_kref_put(tty);
417 }
418 
419 static void klsi_105_set_termios(struct tty_struct *tty,
420 				 struct usb_serial_port *port,
421 				 struct ktermios *old_termios)
422 {
423 	struct klsi_105_private *priv = usb_get_serial_port_data(port);
424 	struct device *dev = &port->dev;
425 	unsigned int iflag = tty->termios.c_iflag;
426 	unsigned int old_iflag = old_termios->c_iflag;
427 	unsigned int cflag = tty->termios.c_cflag;
428 	unsigned int old_cflag = old_termios->c_cflag;
429 	struct klsi_105_port_settings *cfg;
430 	unsigned long flags;
431 	speed_t baud;
432 
433 	cfg = kmalloc(sizeof(*cfg), GFP_KERNEL);
434 	if (!cfg) {
435 		dev_err(dev, "%s - out of memory for config buffer.\n", __func__);
436 		return;
437 	}
438 
439 	/* lock while we are modifying the settings */
440 	spin_lock_irqsave(&priv->lock, flags);
441 
442 	/*
443 	 * Update baud rate
444 	 */
445 	baud = tty_get_baud_rate(tty);
446 
447 	if ((cflag & CBAUD) != (old_cflag & CBAUD)) {
448 		/* reassert DTR and (maybe) RTS on transition from B0 */
449 		if ((old_cflag & CBAUD) == B0) {
450 			dev_dbg(dev, "%s: baud was B0\n", __func__);
451 #if 0
452 			priv->control_state |= TIOCM_DTR;
453 			/* don't set RTS if using hardware flow control */
454 			if (!(old_cflag & CRTSCTS))
455 				priv->control_state |= TIOCM_RTS;
456 			mct_u232_set_modem_ctrl(serial, priv->control_state);
457 #endif
458 		}
459 	}
460 	switch (baud) {
461 	case 0: /* handled below */
462 		break;
463 	case 1200:
464 		priv->cfg.baudrate = kl5kusb105a_sio_b1200;
465 		break;
466 	case 2400:
467 		priv->cfg.baudrate = kl5kusb105a_sio_b2400;
468 		break;
469 	case 4800:
470 		priv->cfg.baudrate = kl5kusb105a_sio_b4800;
471 		break;
472 	case 9600:
473 		priv->cfg.baudrate = kl5kusb105a_sio_b9600;
474 		break;
475 	case 19200:
476 		priv->cfg.baudrate = kl5kusb105a_sio_b19200;
477 		break;
478 	case 38400:
479 		priv->cfg.baudrate = kl5kusb105a_sio_b38400;
480 		break;
481 	case 57600:
482 		priv->cfg.baudrate = kl5kusb105a_sio_b57600;
483 		break;
484 	case 115200:
485 		priv->cfg.baudrate = kl5kusb105a_sio_b115200;
486 		break;
487 	default:
488 		dev_dbg(dev, "KLSI USB->Serial converter: unsupported baudrate request, using default of 9600");
489 		priv->cfg.baudrate = kl5kusb105a_sio_b9600;
490 		baud = 9600;
491 		break;
492 	}
493 	if ((cflag & CBAUD) == B0) {
494 		dev_dbg(dev, "%s: baud is B0\n", __func__);
495 		/* Drop RTS and DTR */
496 		/* maybe this should be simulated by sending read
497 		 * disable and read enable messages?
498 		 */
499 		;
500 #if 0
501 		priv->control_state &= ~(TIOCM_DTR | TIOCM_RTS);
502 		mct_u232_set_modem_ctrl(serial, priv->control_state);
503 #endif
504 	}
505 	tty_encode_baud_rate(tty, baud, baud);
506 
507 	if ((cflag & CSIZE) != (old_cflag & CSIZE)) {
508 		/* set the number of data bits */
509 		switch (cflag & CSIZE) {
510 		case CS5:
511 			dev_dbg(dev, "%s - 5 bits/byte not supported\n", __func__);
512 			spin_unlock_irqrestore(&priv->lock, flags);
513 			goto err;
514 		case CS6:
515 			dev_dbg(dev, "%s - 6 bits/byte not supported\n", __func__);
516 			spin_unlock_irqrestore(&priv->lock, flags);
517 			goto err;
518 		case CS7:
519 			priv->cfg.databits = kl5kusb105a_dtb_7;
520 			break;
521 		case CS8:
522 			priv->cfg.databits = kl5kusb105a_dtb_8;
523 			break;
524 		default:
525 			dev_err(dev, "CSIZE was not CS5-CS8, using default of 8\n");
526 			priv->cfg.databits = kl5kusb105a_dtb_8;
527 			break;
528 		}
529 	}
530 
531 	/*
532 	 * Update line control register (LCR)
533 	 */
534 	if ((cflag & (PARENB|PARODD)) != (old_cflag & (PARENB|PARODD))
535 	    || (cflag & CSTOPB) != (old_cflag & CSTOPB)) {
536 		/* Not currently supported */
537 		tty->termios.c_cflag &= ~(PARENB|PARODD|CSTOPB);
538 #if 0
539 		priv->last_lcr = 0;
540 
541 		/* set the parity */
542 		if (cflag & PARENB)
543 			priv->last_lcr |= (cflag & PARODD) ?
544 				MCT_U232_PARITY_ODD : MCT_U232_PARITY_EVEN;
545 		else
546 			priv->last_lcr |= MCT_U232_PARITY_NONE;
547 
548 		/* set the number of stop bits */
549 		priv->last_lcr |= (cflag & CSTOPB) ?
550 			MCT_U232_STOP_BITS_2 : MCT_U232_STOP_BITS_1;
551 
552 		mct_u232_set_line_ctrl(serial, priv->last_lcr);
553 #endif
554 		;
555 	}
556 	/*
557 	 * Set flow control: well, I do not really now how to handle DTR/RTS.
558 	 * Just do what we have seen with SniffUSB on Win98.
559 	 */
560 	if ((iflag & IXOFF) != (old_iflag & IXOFF)
561 	    || (iflag & IXON) != (old_iflag & IXON)
562 	    ||  (cflag & CRTSCTS) != (old_cflag & CRTSCTS)) {
563 		/* Not currently supported */
564 		tty->termios.c_cflag &= ~CRTSCTS;
565 		/* Drop DTR/RTS if no flow control otherwise assert */
566 #if 0
567 		if ((iflag & IXOFF) || (iflag & IXON) || (cflag & CRTSCTS))
568 			priv->control_state |= TIOCM_DTR | TIOCM_RTS;
569 		else
570 			priv->control_state &= ~(TIOCM_DTR | TIOCM_RTS);
571 		mct_u232_set_modem_ctrl(serial, priv->control_state);
572 #endif
573 		;
574 	}
575 	memcpy(cfg, &priv->cfg, sizeof(*cfg));
576 	spin_unlock_irqrestore(&priv->lock, flags);
577 
578 	/* now commit changes to device */
579 	klsi_105_chg_port_settings(port, cfg);
580 err:
581 	kfree(cfg);
582 }
583 
584 #if 0
585 static void mct_u232_break_ctl(struct tty_struct *tty, int break_state)
586 {
587 	struct usb_serial_port *port = tty->driver_data;
588 	struct usb_serial *serial = port->serial;
589 	struct mct_u232_private *priv =
590 				(struct mct_u232_private *)port->private;
591 	unsigned char lcr = priv->last_lcr;
592 
593 	dev_dbg(&port->dev, "%s - state=%d\n", __func__, break_state);
594 
595 	/* LOCKING */
596 	if (break_state)
597 		lcr |= MCT_U232_SET_BREAK;
598 
599 	mct_u232_set_line_ctrl(serial, lcr);
600 }
601 #endif
602 
603 static int klsi_105_tiocmget(struct tty_struct *tty)
604 {
605 	struct usb_serial_port *port = tty->driver_data;
606 	struct klsi_105_private *priv = usb_get_serial_port_data(port);
607 	unsigned long flags;
608 	int rc;
609 	unsigned long line_state;
610 
611 	rc = klsi_105_get_line_state(port, &line_state);
612 	if (rc < 0) {
613 		dev_err(&port->dev,
614 			"Reading line control failed (error = %d)\n", rc);
615 		/* better return value? EAGAIN? */
616 		return rc;
617 	}
618 
619 	spin_lock_irqsave(&priv->lock, flags);
620 	priv->line_state = line_state;
621 	spin_unlock_irqrestore(&priv->lock, flags);
622 	dev_dbg(&port->dev, "%s - read line state 0x%lx\n", __func__, line_state);
623 	return (int)line_state;
624 }
625 
626 static int klsi_105_tiocmset(struct tty_struct *tty,
627 			     unsigned int set, unsigned int clear)
628 {
629 	int retval = -EINVAL;
630 
631 /* if this ever gets implemented, it should be done something like this:
632 	struct usb_serial *serial = port->serial;
633 	struct klsi_105_private *priv = usb_get_serial_port_data(port);
634 	unsigned long flags;
635 	int control;
636 
637 	spin_lock_irqsave (&priv->lock, flags);
638 	if (set & TIOCM_RTS)
639 		priv->control_state |= TIOCM_RTS;
640 	if (set & TIOCM_DTR)
641 		priv->control_state |= TIOCM_DTR;
642 	if (clear & TIOCM_RTS)
643 		priv->control_state &= ~TIOCM_RTS;
644 	if (clear & TIOCM_DTR)
645 		priv->control_state &= ~TIOCM_DTR;
646 	control = priv->control_state;
647 	spin_unlock_irqrestore (&priv->lock, flags);
648 	retval = mct_u232_set_modem_ctrl(serial, control);
649 */
650 	return retval;
651 }
652 
653 module_usb_serial_driver(serial_drivers, id_table);
654 
655 MODULE_AUTHOR(DRIVER_AUTHOR);
656 MODULE_DESCRIPTION(DRIVER_DESC);
657 MODULE_LICENSE("GPL");
658