xref: /openbmc/linux/drivers/usb/serial/ssu100.c (revision 32078f915d1acab356080b144aa89fe3487f3979)
1 /*
2  * usb-serial driver for Quatech SSU-100
3  *
4  * based on ftdi_sio.c and the original serqt_usb.c from Quatech
5  *
6  */
7 
8 #include <linux/errno.h>
9 #include <linux/init.h>
10 #include <linux/slab.h>
11 #include <linux/tty.h>
12 #include <linux/tty_driver.h>
13 #include <linux/tty_flip.h>
14 #include <linux/module.h>
15 #include <linux/serial.h>
16 #include <linux/usb.h>
17 #include <linux/usb/serial.h>
18 #include <linux/serial_reg.h>
19 #include <linux/uaccess.h>
20 
21 #define QT_OPEN_CLOSE_CHANNEL       0xca
22 #define QT_SET_GET_DEVICE           0xc2
23 #define QT_SET_GET_REGISTER         0xc0
24 #define QT_GET_SET_PREBUF_TRIG_LVL  0xcc
25 #define QT_SET_ATF                  0xcd
26 #define QT_GET_SET_UART             0xc1
27 #define QT_TRANSFER_IN              0xc0
28 #define QT_HW_FLOW_CONTROL_MASK     0xc5
29 #define QT_SW_FLOW_CONTROL_MASK     0xc6
30 
31 #define  SERIAL_MSR_MASK            0xf0
32 
33 #define  SERIAL_CRTSCTS ((UART_MCR_RTS << 8) | UART_MSR_CTS)
34 
35 #define  SERIAL_EVEN_PARITY         (UART_LCR_PARITY | UART_LCR_EPAR)
36 
37 #define  MAX_BAUD_RATE              460800
38 
39 #define ATC_DISABLED                0x00
40 #define DUPMODE_BITS        0xc0
41 #define RR_BITS             0x03
42 #define LOOPMODE_BITS       0x41
43 #define RS232_MODE          0x00
44 #define RTSCTS_TO_CONNECTOR 0x40
45 #define CLKS_X4             0x02
46 #define FULLPWRBIT          0x00000080
47 #define NEXT_BOARD_POWER_BIT        0x00000004
48 
49 static bool debug;
50 
51 /* Version Information */
52 #define DRIVER_VERSION "v0.1"
53 #define DRIVER_DESC "Quatech SSU-100 USB to Serial Driver"
54 
55 #define	USB_VENDOR_ID_QUATECH	0x061d	/* Quatech VID */
56 #define QUATECH_SSU100	0xC020	/* SSU100 */
57 
58 static const struct usb_device_id id_table[] = {
59 	{USB_DEVICE(USB_VENDOR_ID_QUATECH, QUATECH_SSU100)},
60 	{}			/* Terminating entry */
61 };
62 
63 MODULE_DEVICE_TABLE(usb, id_table);
64 
65 
66 static struct usb_driver ssu100_driver = {
67 	.name			       = "ssu100",
68 	.id_table		       = id_table,
69 };
70 
71 struct ssu100_port_private {
72 	spinlock_t status_lock;
73 	u8 shadowLSR;
74 	u8 shadowMSR;
75 	wait_queue_head_t delta_msr_wait; /* Used for TIOCMIWAIT */
76 	struct async_icount icount;
77 };
78 
79 static void ssu100_release(struct usb_serial *serial)
80 {
81 	struct ssu100_port_private *priv = usb_get_serial_port_data(*serial->port);
82 
83 	kfree(priv);
84 }
85 
86 static inline int ssu100_control_msg(struct usb_device *dev,
87 				     u8 request, u16 data, u16 index)
88 {
89 	return usb_control_msg(dev, usb_sndctrlpipe(dev, 0),
90 			       request, 0x40, data, index,
91 			       NULL, 0, 300);
92 }
93 
94 static inline int ssu100_setdevice(struct usb_device *dev, u8 *data)
95 {
96 	u16 x = ((u16)(data[1] << 8) | (u16)(data[0]));
97 
98 	return ssu100_control_msg(dev, QT_SET_GET_DEVICE, x, 0);
99 }
100 
101 
102 static inline int ssu100_getdevice(struct usb_device *dev, u8 *data)
103 {
104 	return usb_control_msg(dev, usb_rcvctrlpipe(dev, 0),
105 			       QT_SET_GET_DEVICE, 0xc0, 0, 0,
106 			       data, 3, 300);
107 }
108 
109 static inline int ssu100_getregister(struct usb_device *dev,
110 				     unsigned short uart,
111 				     unsigned short reg,
112 				     u8 *data)
113 {
114 	return usb_control_msg(dev, usb_rcvctrlpipe(dev, 0),
115 			       QT_SET_GET_REGISTER, 0xc0, reg,
116 			       uart, data, sizeof(*data), 300);
117 
118 }
119 
120 
121 static inline int ssu100_setregister(struct usb_device *dev,
122 				     unsigned short uart,
123 				     unsigned short reg,
124 				     u16 data)
125 {
126 	u16 value = (data << 8) | reg;
127 
128 	return usb_control_msg(dev, usb_sndctrlpipe(dev, 0),
129 			       QT_SET_GET_REGISTER, 0x40, value, uart,
130 			       NULL, 0, 300);
131 
132 }
133 
134 #define set_mctrl(dev, set)		update_mctrl((dev), (set), 0)
135 #define clear_mctrl(dev, clear)	update_mctrl((dev), 0, (clear))
136 
137 /* these do not deal with device that have more than 1 port */
138 static inline int update_mctrl(struct usb_device *dev, unsigned int set,
139 			       unsigned int clear)
140 {
141 	unsigned urb_value;
142 	int result;
143 
144 	if (((set | clear) & (TIOCM_DTR | TIOCM_RTS)) == 0) {
145 		dbg("%s - DTR|RTS not being set|cleared", __func__);
146 		return 0;	/* no change */
147 	}
148 
149 	clear &= ~set;	/* 'set' takes precedence over 'clear' */
150 	urb_value = 0;
151 	if (set & TIOCM_DTR)
152 		urb_value |= UART_MCR_DTR;
153 	if (set & TIOCM_RTS)
154 		urb_value |= UART_MCR_RTS;
155 
156 	result = ssu100_setregister(dev, 0, UART_MCR, urb_value);
157 	if (result < 0)
158 		dbg("%s Error from MODEM_CTRL urb", __func__);
159 
160 	return result;
161 }
162 
163 static int ssu100_initdevice(struct usb_device *dev)
164 {
165 	u8 *data;
166 	int result = 0;
167 
168 	data = kzalloc(3, GFP_KERNEL);
169 	if (!data)
170 		return -ENOMEM;
171 
172 	result = ssu100_getdevice(dev, data);
173 	if (result < 0) {
174 		dbg("%s - get_device failed %i", __func__, result);
175 		goto out;
176 	}
177 
178 	data[1] &= ~FULLPWRBIT;
179 
180 	result = ssu100_setdevice(dev, data);
181 	if (result < 0) {
182 		dbg("%s - setdevice failed %i", __func__, result);
183 		goto out;
184 	}
185 
186 	result = ssu100_control_msg(dev, QT_GET_SET_PREBUF_TRIG_LVL, 128, 0);
187 	if (result < 0) {
188 		dbg("%s - set prebuffer level failed %i", __func__, result);
189 		goto out;
190 	}
191 
192 	result = ssu100_control_msg(dev, QT_SET_ATF, ATC_DISABLED, 0);
193 	if (result < 0) {
194 		dbg("%s - set ATFprebuffer level failed %i", __func__, result);
195 		goto out;
196 	}
197 
198 	result = ssu100_getdevice(dev, data);
199 	if (result < 0) {
200 		dbg("%s - get_device failed %i", __func__, result);
201 		goto out;
202 	}
203 
204 	data[0] &= ~(RR_BITS | DUPMODE_BITS);
205 	data[0] |= CLKS_X4;
206 	data[1] &= ~(LOOPMODE_BITS);
207 	data[1] |= RS232_MODE;
208 
209 	result = ssu100_setdevice(dev, data);
210 	if (result < 0) {
211 		dbg("%s - setdevice failed %i", __func__, result);
212 		goto out;
213 	}
214 
215 out:	kfree(data);
216 	return result;
217 
218 }
219 
220 
221 static void ssu100_set_termios(struct tty_struct *tty,
222 			       struct usb_serial_port *port,
223 			       struct ktermios *old_termios)
224 {
225 	struct usb_device *dev = port->serial->dev;
226 	struct ktermios *termios = tty->termios;
227 	u16 baud, divisor, remainder;
228 	unsigned int cflag = termios->c_cflag;
229 	u16 urb_value = 0; /* will hold the new flags */
230 	int result;
231 
232 	if (cflag & PARENB) {
233 		if (cflag & PARODD)
234 			urb_value |= UART_LCR_PARITY;
235 		else
236 			urb_value |= SERIAL_EVEN_PARITY;
237 	}
238 
239 	switch (cflag & CSIZE) {
240 	case CS5:
241 		urb_value |= UART_LCR_WLEN5;
242 		break;
243 	case CS6:
244 		urb_value |= UART_LCR_WLEN6;
245 		break;
246 	case CS7:
247 		urb_value |= UART_LCR_WLEN7;
248 		break;
249 	default:
250 	case CS8:
251 		urb_value |= UART_LCR_WLEN8;
252 		break;
253 	}
254 
255 	baud = tty_get_baud_rate(tty);
256 	if (!baud)
257 		baud = 9600;
258 
259 	dbg("%s - got baud = %d\n", __func__, baud);
260 
261 
262 	divisor = MAX_BAUD_RATE / baud;
263 	remainder = MAX_BAUD_RATE % baud;
264 	if (((remainder * 2) >= baud) && (baud != 110))
265 		divisor++;
266 
267 	urb_value = urb_value << 8;
268 
269 	result = ssu100_control_msg(dev, QT_GET_SET_UART, divisor, urb_value);
270 	if (result < 0)
271 		dbg("%s - set uart failed", __func__);
272 
273 	if (cflag & CRTSCTS)
274 		result = ssu100_control_msg(dev, QT_HW_FLOW_CONTROL_MASK,
275 					    SERIAL_CRTSCTS, 0);
276 	else
277 		result = ssu100_control_msg(dev, QT_HW_FLOW_CONTROL_MASK,
278 					    0, 0);
279 	if (result < 0)
280 		dbg("%s - set HW flow control failed", __func__);
281 
282 	if (I_IXOFF(tty) || I_IXON(tty)) {
283 		u16 x = ((u16)(START_CHAR(tty) << 8) | (u16)(STOP_CHAR(tty)));
284 
285 		result = ssu100_control_msg(dev, QT_SW_FLOW_CONTROL_MASK,
286 					    x, 0);
287 	} else
288 		result = ssu100_control_msg(dev, QT_SW_FLOW_CONTROL_MASK,
289 					    0, 0);
290 
291 	if (result < 0)
292 		dbg("%s - set SW flow control failed", __func__);
293 
294 }
295 
296 
297 static int ssu100_open(struct tty_struct *tty, struct usb_serial_port *port)
298 {
299 	struct usb_device *dev = port->serial->dev;
300 	struct ssu100_port_private *priv = usb_get_serial_port_data(port);
301 	u8 *data;
302 	int result;
303 	unsigned long flags;
304 
305 	data = kzalloc(2, GFP_KERNEL);
306 	if (!data)
307 		return -ENOMEM;
308 
309 	result = usb_control_msg(dev, usb_rcvctrlpipe(dev, 0),
310 				 QT_OPEN_CLOSE_CHANNEL,
311 				 QT_TRANSFER_IN, 0x01,
312 				 0, data, 2, 300);
313 	if (result < 0) {
314 		dbg("%s - open failed %i", __func__, result);
315 		kfree(data);
316 		return result;
317 	}
318 
319 	spin_lock_irqsave(&priv->status_lock, flags);
320 	priv->shadowLSR = data[0];
321 	priv->shadowMSR = data[1];
322 	spin_unlock_irqrestore(&priv->status_lock, flags);
323 
324 	kfree(data);
325 
326 /* set to 9600 */
327 	result = ssu100_control_msg(dev, QT_GET_SET_UART, 0x30, 0x0300);
328 	if (result < 0)
329 		dbg("%s - set uart failed", __func__);
330 
331 	if (tty)
332 		ssu100_set_termios(tty, port, tty->termios);
333 
334 	return usb_serial_generic_open(tty, port);
335 }
336 
337 static void ssu100_close(struct usb_serial_port *port)
338 {
339 	usb_serial_generic_close(port);
340 }
341 
342 static int get_serial_info(struct usb_serial_port *port,
343 			   struct serial_struct __user *retinfo)
344 {
345 	struct serial_struct tmp;
346 
347 	if (!retinfo)
348 		return -EFAULT;
349 
350 	memset(&tmp, 0, sizeof(tmp));
351 	tmp.line		= port->serial->minor;
352 	tmp.port		= 0;
353 	tmp.irq			= 0;
354 	tmp.flags		= ASYNC_SKIP_TEST | ASYNC_AUTO_IRQ;
355 	tmp.xmit_fifo_size	= port->bulk_out_size;
356 	tmp.baud_base		= 9600;
357 	tmp.close_delay		= 5*HZ;
358 	tmp.closing_wait	= 30*HZ;
359 
360 	if (copy_to_user(retinfo, &tmp, sizeof(*retinfo)))
361 		return -EFAULT;
362 	return 0;
363 }
364 
365 static int wait_modem_info(struct usb_serial_port *port, unsigned int arg)
366 {
367 	struct ssu100_port_private *priv = usb_get_serial_port_data(port);
368 	struct async_icount prev, cur;
369 	unsigned long flags;
370 
371 	spin_lock_irqsave(&priv->status_lock, flags);
372 	prev = priv->icount;
373 	spin_unlock_irqrestore(&priv->status_lock, flags);
374 
375 	while (1) {
376 		wait_event_interruptible(priv->delta_msr_wait,
377 					 ((priv->icount.rng != prev.rng) ||
378 					  (priv->icount.dsr != prev.dsr) ||
379 					  (priv->icount.dcd != prev.dcd) ||
380 					  (priv->icount.cts != prev.cts)));
381 
382 		if (signal_pending(current))
383 			return -ERESTARTSYS;
384 
385 		spin_lock_irqsave(&priv->status_lock, flags);
386 		cur = priv->icount;
387 		spin_unlock_irqrestore(&priv->status_lock, flags);
388 
389 		if ((prev.rng == cur.rng) &&
390 		    (prev.dsr == cur.dsr) &&
391 		    (prev.dcd == cur.dcd) &&
392 		    (prev.cts == cur.cts))
393 			return -EIO;
394 
395 		if ((arg & TIOCM_RNG && (prev.rng != cur.rng)) ||
396 		    (arg & TIOCM_DSR && (prev.dsr != cur.dsr)) ||
397 		    (arg & TIOCM_CD  && (prev.dcd != cur.dcd)) ||
398 		    (arg & TIOCM_CTS && (prev.cts != cur.cts)))
399 			return 0;
400 	}
401 	return 0;
402 }
403 
404 static int ssu100_get_icount(struct tty_struct *tty,
405 			struct serial_icounter_struct *icount)
406 {
407 	struct usb_serial_port *port = tty->driver_data;
408 	struct ssu100_port_private *priv = usb_get_serial_port_data(port);
409 	struct async_icount cnow = priv->icount;
410 
411 	icount->cts = cnow.cts;
412 	icount->dsr = cnow.dsr;
413 	icount->rng = cnow.rng;
414 	icount->dcd = cnow.dcd;
415 	icount->rx = cnow.rx;
416 	icount->tx = cnow.tx;
417 	icount->frame = cnow.frame;
418 	icount->overrun = cnow.overrun;
419 	icount->parity = cnow.parity;
420 	icount->brk = cnow.brk;
421 	icount->buf_overrun = cnow.buf_overrun;
422 
423 	return 0;
424 }
425 
426 
427 
428 static int ssu100_ioctl(struct tty_struct *tty,
429 		    unsigned int cmd, unsigned long arg)
430 {
431 	struct usb_serial_port *port = tty->driver_data;
432 
433 	dbg("%s cmd 0x%04x", __func__, cmd);
434 
435 	switch (cmd) {
436 	case TIOCGSERIAL:
437 		return get_serial_info(port,
438 				       (struct serial_struct __user *) arg);
439 
440 	case TIOCMIWAIT:
441 		return wait_modem_info(port, arg);
442 
443 	default:
444 		break;
445 	}
446 
447 	dbg("%s arg not supported", __func__);
448 
449 	return -ENOIOCTLCMD;
450 }
451 
452 static int ssu100_attach(struct usb_serial *serial)
453 {
454 	struct ssu100_port_private *priv;
455 	struct usb_serial_port *port = *serial->port;
456 
457 	priv = kzalloc(sizeof(*priv), GFP_KERNEL);
458 	if (!priv) {
459 		dev_err(&port->dev, "%s- kmalloc(%Zd) failed.\n", __func__,
460 			sizeof(*priv));
461 		return -ENOMEM;
462 	}
463 
464 	spin_lock_init(&priv->status_lock);
465 	init_waitqueue_head(&priv->delta_msr_wait);
466 	usb_set_serial_port_data(port, priv);
467 
468 	return ssu100_initdevice(serial->dev);
469 }
470 
471 static int ssu100_tiocmget(struct tty_struct *tty)
472 {
473 	struct usb_serial_port *port = tty->driver_data;
474 	struct usb_device *dev = port->serial->dev;
475 	u8 *d;
476 	int r;
477 
478 	d = kzalloc(2, GFP_KERNEL);
479 	if (!d)
480 		return -ENOMEM;
481 
482 	r = ssu100_getregister(dev, 0, UART_MCR, d);
483 	if (r < 0)
484 		goto mget_out;
485 
486 	r = ssu100_getregister(dev, 0, UART_MSR, d+1);
487 	if (r < 0)
488 		goto mget_out;
489 
490 	r = (d[0] & UART_MCR_DTR ? TIOCM_DTR : 0) |
491 		(d[0] & UART_MCR_RTS ? TIOCM_RTS : 0) |
492 		(d[1] & UART_MSR_CTS ? TIOCM_CTS : 0) |
493 		(d[1] & UART_MSR_DCD ? TIOCM_CAR : 0) |
494 		(d[1] & UART_MSR_RI ? TIOCM_RI : 0) |
495 		(d[1] & UART_MSR_DSR ? TIOCM_DSR : 0);
496 
497 mget_out:
498 	kfree(d);
499 	return r;
500 }
501 
502 static int ssu100_tiocmset(struct tty_struct *tty,
503 			   unsigned int set, unsigned int clear)
504 {
505 	struct usb_serial_port *port = tty->driver_data;
506 	struct usb_device *dev = port->serial->dev;
507 
508 	return update_mctrl(dev, set, clear);
509 }
510 
511 static void ssu100_dtr_rts(struct usb_serial_port *port, int on)
512 {
513 	struct usb_device *dev = port->serial->dev;
514 
515 	mutex_lock(&port->serial->disc_mutex);
516 	if (!port->serial->disconnected) {
517 		/* Disable flow control */
518 		if (!on &&
519 		    ssu100_setregister(dev, 0, UART_MCR, 0) < 0)
520 			dev_err(&port->dev, "error from flowcontrol urb\n");
521 		/* drop RTS and DTR */
522 		if (on)
523 			set_mctrl(dev, TIOCM_DTR | TIOCM_RTS);
524 		else
525 			clear_mctrl(dev, TIOCM_DTR | TIOCM_RTS);
526 	}
527 	mutex_unlock(&port->serial->disc_mutex);
528 }
529 
530 static void ssu100_update_msr(struct usb_serial_port *port, u8 msr)
531 {
532 	struct ssu100_port_private *priv = usb_get_serial_port_data(port);
533 	unsigned long flags;
534 
535 	spin_lock_irqsave(&priv->status_lock, flags);
536 	priv->shadowMSR = msr;
537 	spin_unlock_irqrestore(&priv->status_lock, flags);
538 
539 	if (msr & UART_MSR_ANY_DELTA) {
540 		/* update input line counters */
541 		if (msr & UART_MSR_DCTS)
542 			priv->icount.cts++;
543 		if (msr & UART_MSR_DDSR)
544 			priv->icount.dsr++;
545 		if (msr & UART_MSR_DDCD)
546 			priv->icount.dcd++;
547 		if (msr & UART_MSR_TERI)
548 			priv->icount.rng++;
549 		wake_up_interruptible(&priv->delta_msr_wait);
550 	}
551 }
552 
553 static void ssu100_update_lsr(struct usb_serial_port *port, u8 lsr,
554 			      char *tty_flag)
555 {
556 	struct ssu100_port_private *priv = usb_get_serial_port_data(port);
557 	unsigned long flags;
558 
559 	spin_lock_irqsave(&priv->status_lock, flags);
560 	priv->shadowLSR = lsr;
561 	spin_unlock_irqrestore(&priv->status_lock, flags);
562 
563 	*tty_flag = TTY_NORMAL;
564 	if (lsr & UART_LSR_BRK_ERROR_BITS) {
565 		/* we always want to update icount, but we only want to
566 		 * update tty_flag for one case */
567 		if (lsr & UART_LSR_BI) {
568 			priv->icount.brk++;
569 			*tty_flag = TTY_BREAK;
570 			usb_serial_handle_break(port);
571 		}
572 		if (lsr & UART_LSR_PE) {
573 			priv->icount.parity++;
574 			if (*tty_flag == TTY_NORMAL)
575 				*tty_flag = TTY_PARITY;
576 		}
577 		if (lsr & UART_LSR_FE) {
578 			priv->icount.frame++;
579 			if (*tty_flag == TTY_NORMAL)
580 				*tty_flag = TTY_FRAME;
581 		}
582 		if (lsr & UART_LSR_OE){
583 			priv->icount.overrun++;
584 			if (*tty_flag == TTY_NORMAL)
585 				*tty_flag = TTY_OVERRUN;
586 		}
587 	}
588 
589 }
590 
591 static int ssu100_process_packet(struct urb *urb,
592 				 struct tty_struct *tty)
593 {
594 	struct usb_serial_port *port = urb->context;
595 	char *packet = (char *)urb->transfer_buffer;
596 	char flag = TTY_NORMAL;
597 	u32 len = urb->actual_length;
598 	int i;
599 	char *ch;
600 
601 	if ((len >= 4) &&
602 	    (packet[0] == 0x1b) && (packet[1] == 0x1b) &&
603 	    ((packet[2] == 0x00) || (packet[2] == 0x01))) {
604 		if (packet[2] == 0x00) {
605 			ssu100_update_lsr(port, packet[3], &flag);
606 			if (flag == TTY_OVERRUN)
607 				tty_insert_flip_char(tty, 0, TTY_OVERRUN);
608 		}
609 		if (packet[2] == 0x01)
610 			ssu100_update_msr(port, packet[3]);
611 
612 		len -= 4;
613 		ch = packet + 4;
614 	} else
615 		ch = packet;
616 
617 	if (!len)
618 		return 0;	/* status only */
619 
620 	if (port->port.console && port->sysrq) {
621 		for (i = 0; i < len; i++, ch++) {
622 			if (!usb_serial_handle_sysrq_char(port, *ch))
623 				tty_insert_flip_char(tty, *ch, flag);
624 		}
625 	} else
626 		tty_insert_flip_string_fixed_flag(tty, ch, flag, len);
627 
628 	return len;
629 }
630 
631 static void ssu100_process_read_urb(struct urb *urb)
632 {
633 	struct usb_serial_port *port = urb->context;
634 	struct tty_struct *tty;
635 	int count;
636 
637 	tty = tty_port_tty_get(&port->port);
638 	if (!tty)
639 		return;
640 
641 	count = ssu100_process_packet(urb, tty);
642 
643 	if (count)
644 		tty_flip_buffer_push(tty);
645 	tty_kref_put(tty);
646 }
647 
648 static struct usb_serial_driver ssu100_device = {
649 	.driver = {
650 		.owner = THIS_MODULE,
651 		.name = "ssu100",
652 	},
653 	.description	     = DRIVER_DESC,
654 	.id_table	     = id_table,
655 	.num_ports	     = 1,
656 	.open		     = ssu100_open,
657 	.close		     = ssu100_close,
658 	.attach              = ssu100_attach,
659 	.release             = ssu100_release,
660 	.dtr_rts             = ssu100_dtr_rts,
661 	.process_read_urb    = ssu100_process_read_urb,
662 	.tiocmget            = ssu100_tiocmget,
663 	.tiocmset            = ssu100_tiocmset,
664 	.get_icount	     = ssu100_get_icount,
665 	.ioctl               = ssu100_ioctl,
666 	.set_termios         = ssu100_set_termios,
667 	.disconnect          = usb_serial_generic_disconnect,
668 };
669 
670 static struct usb_serial_driver * const serial_drivers[] = {
671 	&ssu100_device, NULL
672 };
673 
674 module_usb_serial_driver(ssu100_driver, serial_drivers);
675 
676 MODULE_DESCRIPTION(DRIVER_DESC);
677 MODULE_LICENSE("GPL");
678 
679 module_param(debug, bool, S_IRUGO | S_IWUSR);
680 MODULE_PARM_DESC(debug, "Debug enabled or not");
681