1/* This is the serial hardware link layer (HLL) for the Gigaset 307x isdn
2 * DECT base (aka Sinus 45 isdn) using the RS232 DECT data module M101,
3 * written as a line discipline.
4 *
5 * =====================================================================
6 * This program is free software; you can redistribute it and/or
7 * modify it under the terms of the GNU General Public License as
8 * published by the Free Software Foundation; either version 2 of
9 * the License, or (at your option) any later version.
10 * =====================================================================
11 */
12
13#include "gigaset.h"
14#include <linux/module.h>
15#include <linux/moduleparam.h>
16#include <linux/platform_device.h>
17#include <linux/completion.h>
18
19/* Version Information */
20#define DRIVER_AUTHOR "Tilman Schmidt"
21#define DRIVER_DESC "Serial Driver for Gigaset 307x using Siemens M101"
22
23#define GIGASET_MINORS     1
24#define GIGASET_MINOR      0
25#define GIGASET_MODULENAME "ser_gigaset"
26#define GIGASET_DEVNAME    "ttyGS"
27
28/* length limit according to Siemens 3070usb-protokoll.doc ch. 2.1 */
29#define IF_WRITEBUF 264
30
31MODULE_AUTHOR(DRIVER_AUTHOR);
32MODULE_DESCRIPTION(DRIVER_DESC);
33MODULE_LICENSE("GPL");
34MODULE_ALIAS_LDISC(N_GIGASET_M101);
35
36static int startmode = SM_ISDN;
37module_param(startmode, int, S_IRUGO);
38MODULE_PARM_DESC(startmode, "initial operation mode");
39static int cidmode = 1;
40module_param(cidmode, int, S_IRUGO);
41MODULE_PARM_DESC(cidmode, "stay in CID mode when idle");
42
43static struct gigaset_driver *driver;
44
45struct ser_cardstate {
46	struct platform_device	dev;
47	struct tty_struct	*tty;
48	atomic_t		refcnt;
49	struct completion	dead_cmp;
50};
51
52static struct platform_driver device_driver = {
53	.driver = {
54		.name = GIGASET_MODULENAME,
55	},
56};
57
58static void flush_send_queue(struct cardstate *);
59
60/* transmit data from current open skb
61 * result: number of bytes sent or error code < 0
62 */
63static int write_modem(struct cardstate *cs)
64{
65	struct tty_struct *tty = cs->hw.ser->tty;
66	struct bc_state *bcs = &cs->bcs[0];	/* only one channel */
67	struct sk_buff *skb = bcs->tx_skb;
68	int sent = -EOPNOTSUPP;
69
70	WARN_ON(!tty || !tty->ops || !skb);
71
72	if (!skb->len) {
73		dev_kfree_skb_any(skb);
74		bcs->tx_skb = NULL;
75		return -EINVAL;
76	}
77
78	set_bit(TTY_DO_WRITE_WAKEUP, &tty->flags);
79	if (tty->ops->write)
80		sent = tty->ops->write(tty, skb->data, skb->len);
81	gig_dbg(DEBUG_OUTPUT, "write_modem: sent %d", sent);
82	if (sent < 0) {
83		/* error */
84		flush_send_queue(cs);
85		return sent;
86	}
87	skb_pull(skb, sent);
88	if (!skb->len) {
89		/* skb sent completely */
90		gigaset_skb_sent(bcs, skb);
91
92		gig_dbg(DEBUG_INTR, "kfree skb (Adr: %lx)!",
93			(unsigned long) skb);
94		dev_kfree_skb_any(skb);
95		bcs->tx_skb = NULL;
96	}
97	return sent;
98}
99
100/*
101 * transmit first queued command buffer
102 * result: number of bytes sent or error code < 0
103 */
104static int send_cb(struct cardstate *cs)
105{
106	struct tty_struct *tty = cs->hw.ser->tty;
107	struct cmdbuf_t *cb, *tcb;
108	unsigned long flags;
109	int sent = 0;
110
111	WARN_ON(!tty || !tty->ops);
112
113	cb = cs->cmdbuf;
114	if (!cb)
115		return 0;	/* nothing to do */
116
117	if (cb->len) {
118		set_bit(TTY_DO_WRITE_WAKEUP, &tty->flags);
119		sent = tty->ops->write(tty, cb->buf + cb->offset, cb->len);
120		if (sent < 0) {
121			/* error */
122			gig_dbg(DEBUG_OUTPUT, "send_cb: write error %d", sent);
123			flush_send_queue(cs);
124			return sent;
125		}
126		cb->offset += sent;
127		cb->len -= sent;
128		gig_dbg(DEBUG_OUTPUT, "send_cb: sent %d, left %u, queued %u",
129			sent, cb->len, cs->cmdbytes);
130	}
131
132	while (cb && !cb->len) {
133		spin_lock_irqsave(&cs->cmdlock, flags);
134		cs->cmdbytes -= cs->curlen;
135		tcb = cb;
136		cs->cmdbuf = cb = cb->next;
137		if (cb) {
138			cb->prev = NULL;
139			cs->curlen = cb->len;
140		} else {
141			cs->lastcmdbuf = NULL;
142			cs->curlen = 0;
143		}
144		spin_unlock_irqrestore(&cs->cmdlock, flags);
145
146		if (tcb->wake_tasklet)
147			tasklet_schedule(tcb->wake_tasklet);
148		kfree(tcb);
149	}
150	return sent;
151}
152
153/*
154 * send queue tasklet
155 * If there is already a skb opened, put data to the transfer buffer
156 * by calling "write_modem".
157 * Otherwise take a new skb out of the queue.
158 */
159static void gigaset_modem_fill(unsigned long data)
160{
161	struct cardstate *cs = (struct cardstate *) data;
162	struct bc_state *bcs;
163	struct sk_buff *nextskb;
164	int sent = 0;
165
166	if (!cs) {
167		gig_dbg(DEBUG_OUTPUT, "%s: no cardstate", __func__);
168		return;
169	}
170	bcs = cs->bcs;
171	if (!bcs) {
172		gig_dbg(DEBUG_OUTPUT, "%s: no cardstate", __func__);
173		return;
174	}
175	if (!bcs->tx_skb) {
176		/* no skb is being sent; send command if any */
177		sent = send_cb(cs);
178		gig_dbg(DEBUG_OUTPUT, "%s: send_cb -> %d", __func__, sent);
179		if (sent)
180			/* something sent or error */
181			return;
182
183		/* no command to send; get skb */
184		nextskb = skb_dequeue(&bcs->squeue);
185		if (!nextskb)
186			/* no skb either, nothing to do */
187			return;
188		bcs->tx_skb = nextskb;
189
190		gig_dbg(DEBUG_INTR, "Dequeued skb (Adr: %lx)",
191			(unsigned long) bcs->tx_skb);
192	}
193
194	/* send skb */
195	gig_dbg(DEBUG_OUTPUT, "%s: tx_skb", __func__);
196	if (write_modem(cs) < 0)
197		gig_dbg(DEBUG_OUTPUT, "%s: write_modem failed", __func__);
198}
199
200/*
201 * throw away all data queued for sending
202 */
203static void flush_send_queue(struct cardstate *cs)
204{
205	struct sk_buff *skb;
206	struct cmdbuf_t *cb;
207	unsigned long flags;
208
209	/* command queue */
210	spin_lock_irqsave(&cs->cmdlock, flags);
211	while ((cb = cs->cmdbuf) != NULL) {
212		cs->cmdbuf = cb->next;
213		if (cb->wake_tasklet)
214			tasklet_schedule(cb->wake_tasklet);
215		kfree(cb);
216	}
217	cs->cmdbuf = cs->lastcmdbuf = NULL;
218	cs->cmdbytes = cs->curlen = 0;
219	spin_unlock_irqrestore(&cs->cmdlock, flags);
220
221	/* data queue */
222	if (cs->bcs->tx_skb)
223		dev_kfree_skb_any(cs->bcs->tx_skb);
224	while ((skb = skb_dequeue(&cs->bcs->squeue)) != NULL)
225		dev_kfree_skb_any(skb);
226}
227
228
229/* Gigaset Driver Interface */
230/* ======================== */
231
232/*
233 * queue an AT command string for transmission to the Gigaset device
234 * parameters:
235 *	cs		controller state structure
236 *	buf		buffer containing the string to send
237 *	len		number of characters to send
238 *	wake_tasklet	tasklet to run when transmission is complete, or NULL
239 * return value:
240 *	number of bytes queued, or error code < 0
241 */
242static int gigaset_write_cmd(struct cardstate *cs, struct cmdbuf_t *cb)
243{
244	unsigned long flags;
245
246	gigaset_dbg_buffer(cs->mstate != MS_LOCKED ?
247			   DEBUG_TRANSCMD : DEBUG_LOCKCMD,
248			   "CMD Transmit", cb->len, cb->buf);
249
250	spin_lock_irqsave(&cs->cmdlock, flags);
251	cb->prev = cs->lastcmdbuf;
252	if (cs->lastcmdbuf)
253		cs->lastcmdbuf->next = cb;
254	else {
255		cs->cmdbuf = cb;
256		cs->curlen = cb->len;
257	}
258	cs->cmdbytes += cb->len;
259	cs->lastcmdbuf = cb;
260	spin_unlock_irqrestore(&cs->cmdlock, flags);
261
262	spin_lock_irqsave(&cs->lock, flags);
263	if (cs->connected)
264		tasklet_schedule(&cs->write_tasklet);
265	spin_unlock_irqrestore(&cs->lock, flags);
266	return cb->len;
267}
268
269/*
270 * tty_driver.write_room interface routine
271 * return number of characters the driver will accept to be written
272 * parameter:
273 *	controller state structure
274 * return value:
275 *	number of characters
276 */
277static int gigaset_write_room(struct cardstate *cs)
278{
279	unsigned bytes;
280
281	bytes = cs->cmdbytes;
282	return bytes < IF_WRITEBUF ? IF_WRITEBUF - bytes : 0;
283}
284
285/*
286 * tty_driver.chars_in_buffer interface routine
287 * return number of characters waiting to be sent
288 * parameter:
289 *	controller state structure
290 * return value:
291 *	number of characters
292 */
293static int gigaset_chars_in_buffer(struct cardstate *cs)
294{
295	return cs->cmdbytes;
296}
297
298/*
299 * implementation of ioctl(GIGASET_BRKCHARS)
300 * parameter:
301 *	controller state structure
302 * return value:
303 *	-EINVAL (unimplemented function)
304 */
305static int gigaset_brkchars(struct cardstate *cs, const unsigned char buf[6])
306{
307	/* not implemented */
308	return -EINVAL;
309}
310
311/*
312 * Open B channel
313 * Called by "do_action" in ev-layer.c
314 */
315static int gigaset_init_bchannel(struct bc_state *bcs)
316{
317	/* nothing to do for M10x */
318	gigaset_bchannel_up(bcs);
319	return 0;
320}
321
322/*
323 * Close B channel
324 * Called by "do_action" in ev-layer.c
325 */
326static int gigaset_close_bchannel(struct bc_state *bcs)
327{
328	/* nothing to do for M10x */
329	gigaset_bchannel_down(bcs);
330	return 0;
331}
332
333/*
334 * Set up B channel structure
335 * This is called by "gigaset_initcs" in common.c
336 */
337static int gigaset_initbcshw(struct bc_state *bcs)
338{
339	/* unused */
340	bcs->hw.ser = NULL;
341	return 0;
342}
343
344/*
345 * Free B channel structure
346 * Called by "gigaset_freebcs" in common.c
347 */
348static void gigaset_freebcshw(struct bc_state *bcs)
349{
350	/* unused */
351}
352
353/*
354 * Reinitialize B channel structure
355 * This is called by "bcs_reinit" in common.c
356 */
357static void gigaset_reinitbcshw(struct bc_state *bcs)
358{
359	/* nothing to do for M10x */
360}
361
362/*
363 * Free hardware specific device data
364 * This will be called by "gigaset_freecs" in common.c
365 */
366static void gigaset_freecshw(struct cardstate *cs)
367{
368	tasklet_kill(&cs->write_tasklet);
369	if (!cs->hw.ser)
370		return;
371	platform_device_unregister(&cs->hw.ser->dev);
372}
373
374static void gigaset_device_release(struct device *dev)
375{
376	struct cardstate *cs = dev_get_drvdata(dev);
377
378	if (!cs)
379		return;
380	dev_set_drvdata(dev, NULL);
381	kfree(cs->hw.ser);
382	cs->hw.ser = NULL;
383}
384
385/*
386 * Set up hardware specific device data
387 * This is called by "gigaset_initcs" in common.c
388 */
389static int gigaset_initcshw(struct cardstate *cs)
390{
391	int rc;
392	struct ser_cardstate *scs;
393
394	scs = kzalloc(sizeof(struct ser_cardstate), GFP_KERNEL);
395	if (!scs) {
396		pr_err("out of memory\n");
397		return -ENOMEM;
398	}
399	cs->hw.ser = scs;
400
401	cs->hw.ser->dev.name = GIGASET_MODULENAME;
402	cs->hw.ser->dev.id = cs->minor_index;
403	cs->hw.ser->dev.dev.release = gigaset_device_release;
404	rc = platform_device_register(&cs->hw.ser->dev);
405	if (rc != 0) {
406		pr_err("error %d registering platform device\n", rc);
407		kfree(cs->hw.ser);
408		cs->hw.ser = NULL;
409		return rc;
410	}
411	dev_set_drvdata(&cs->hw.ser->dev.dev, cs);
412
413	tasklet_init(&cs->write_tasklet,
414		     gigaset_modem_fill, (unsigned long) cs);
415	return 0;
416}
417
418/*
419 * set modem control lines
420 * Parameters:
421 *	card state structure
422 *	modem control line state ([TIOCM_DTR]|[TIOCM_RTS])
423 * Called by "gigaset_start" and "gigaset_enterconfigmode" in common.c
424 * and by "if_lock" and "if_termios" in interface.c
425 */
426static int gigaset_set_modem_ctrl(struct cardstate *cs, unsigned old_state,
427				  unsigned new_state)
428{
429	struct tty_struct *tty = cs->hw.ser->tty;
430	unsigned int set, clear;
431
432	WARN_ON(!tty || !tty->ops);
433	/* tiocmset is an optional tty driver method */
434	if (!tty->ops->tiocmset)
435		return -EINVAL;
436	set = new_state & ~old_state;
437	clear = old_state & ~new_state;
438	if (!set && !clear)
439		return 0;
440	gig_dbg(DEBUG_IF, "tiocmset set %x clear %x", set, clear);
441	return tty->ops->tiocmset(tty, set, clear);
442}
443
444static int gigaset_baud_rate(struct cardstate *cs, unsigned cflag)
445{
446	return -EINVAL;
447}
448
449static int gigaset_set_line_ctrl(struct cardstate *cs, unsigned cflag)
450{
451	return -EINVAL;
452}
453
454static const struct gigaset_ops ops = {
455	gigaset_write_cmd,
456	gigaset_write_room,
457	gigaset_chars_in_buffer,
458	gigaset_brkchars,
459	gigaset_init_bchannel,
460	gigaset_close_bchannel,
461	gigaset_initbcshw,
462	gigaset_freebcshw,
463	gigaset_reinitbcshw,
464	gigaset_initcshw,
465	gigaset_freecshw,
466	gigaset_set_modem_ctrl,
467	gigaset_baud_rate,
468	gigaset_set_line_ctrl,
469	gigaset_m10x_send_skb,	/* asyncdata.c */
470	gigaset_m10x_input,	/* asyncdata.c */
471};
472
473
474/* Line Discipline Interface */
475/* ========================= */
476
477/* helper functions for cardstate refcounting */
478static struct cardstate *cs_get(struct tty_struct *tty)
479{
480	struct cardstate *cs = tty->disc_data;
481
482	if (!cs || !cs->hw.ser) {
483		gig_dbg(DEBUG_ANY, "%s: no cardstate", __func__);
484		return NULL;
485	}
486	atomic_inc(&cs->hw.ser->refcnt);
487	return cs;
488}
489
490static void cs_put(struct cardstate *cs)
491{
492	if (atomic_dec_and_test(&cs->hw.ser->refcnt))
493		complete(&cs->hw.ser->dead_cmp);
494}
495
496/*
497 * Called by the tty driver when the line discipline is pushed onto the tty.
498 * Called in process context.
499 */
500static int
501gigaset_tty_open(struct tty_struct *tty)
502{
503	struct cardstate *cs;
504	int rc;
505
506	gig_dbg(DEBUG_INIT, "Starting HLL for Gigaset M101");
507
508	pr_info(DRIVER_DESC "\n");
509
510	if (!driver) {
511		pr_err("%s: no driver structure\n", __func__);
512		return -ENODEV;
513	}
514
515	/* allocate memory for our device state and initialize it */
516	cs = gigaset_initcs(driver, 1, 1, 0, cidmode, GIGASET_MODULENAME);
517	if (!cs) {
518		rc = -ENODEV;
519		goto error;
520	}
521
522	cs->dev = &cs->hw.ser->dev.dev;
523	cs->hw.ser->tty = tty;
524	atomic_set(&cs->hw.ser->refcnt, 1);
525	init_completion(&cs->hw.ser->dead_cmp);
526	tty->disc_data = cs;
527
528	/* Set the amount of data we're willing to receive per call
529	 * from the hardware driver to half of the input buffer size
530	 * to leave some reserve.
531	 * Note: We don't do flow control towards the hardware driver.
532	 * If more data is received than will fit into the input buffer,
533	 * it will be dropped and an error will be logged. This should
534	 * never happen as the device is slow and the buffer size ample.
535	 */
536	tty->receive_room = RBUFSIZE/2;
537
538	/* OK.. Initialization of the datastructures and the HW is done.. Now
539	 * startup system and notify the LL that we are ready to run
540	 */
541	if (startmode == SM_LOCKED)
542		cs->mstate = MS_LOCKED;
543	rc = gigaset_start(cs);
544	if (rc < 0) {
545		tasklet_kill(&cs->write_tasklet);
546		goto error;
547	}
548
549	gig_dbg(DEBUG_INIT, "Startup of HLL done");
550	return 0;
551
552error:
553	gig_dbg(DEBUG_INIT, "Startup of HLL failed");
554	tty->disc_data = NULL;
555	gigaset_freecs(cs);
556	return rc;
557}
558
559/*
560 * Called by the tty driver when the line discipline is removed.
561 * Called from process context.
562 */
563static void
564gigaset_tty_close(struct tty_struct *tty)
565{
566	struct cardstate *cs = tty->disc_data;
567
568	gig_dbg(DEBUG_INIT, "Stopping HLL for Gigaset M101");
569
570	if (!cs) {
571		gig_dbg(DEBUG_INIT, "%s: no cardstate", __func__);
572		return;
573	}
574
575	/* prevent other callers from entering ldisc methods */
576	tty->disc_data = NULL;
577
578	if (!cs->hw.ser)
579		pr_err("%s: no hw cardstate\n", __func__);
580	else {
581		/* wait for running methods to finish */
582		if (!atomic_dec_and_test(&cs->hw.ser->refcnt))
583			wait_for_completion(&cs->hw.ser->dead_cmp);
584	}
585
586	/* stop operations */
587	gigaset_stop(cs);
588	tasklet_kill(&cs->write_tasklet);
589	flush_send_queue(cs);
590	cs->dev = NULL;
591	gigaset_freecs(cs);
592
593	gig_dbg(DEBUG_INIT, "Shutdown of HLL done");
594}
595
596/*
597 * Called by the tty driver when the tty line is hung up.
598 * Wait for I/O to driver to complete and unregister ISDN device.
599 * This is already done by the close routine, so just call that.
600 * Called from process context.
601 */
602static int gigaset_tty_hangup(struct tty_struct *tty)
603{
604	gigaset_tty_close(tty);
605	return 0;
606}
607
608/*
609 * Ioctl on the tty.
610 * Called in process context only.
611 * May be re-entered by multiple ioctl calling threads.
612 */
613static int
614gigaset_tty_ioctl(struct tty_struct *tty, struct file *file,
615		  unsigned int cmd, unsigned long arg)
616{
617	struct cardstate *cs = cs_get(tty);
618	int rc, val;
619	int __user *p = (int __user *)arg;
620
621	if (!cs)
622		return -ENXIO;
623
624	switch (cmd) {
625
626	case FIONREAD:
627		/* unused, always return zero */
628		val = 0;
629		rc = put_user(val, p);
630		break;
631
632	case TCFLSH:
633		/* flush our buffers and the serial port's buffer */
634		switch (arg) {
635		case TCIFLUSH:
636			/* no own input buffer to flush */
637			break;
638		case TCIOFLUSH:
639		case TCOFLUSH:
640			flush_send_queue(cs);
641			break;
642		}
643		/* Pass through */
644
645	default:
646		/* pass through to underlying serial device */
647		rc = n_tty_ioctl_helper(tty, file, cmd, arg);
648		break;
649	}
650	cs_put(cs);
651	return rc;
652}
653
654/*
655 * Called by the tty driver when a block of data has been received.
656 * Will not be re-entered while running but other ldisc functions
657 * may be called in parallel.
658 * Can be called from hard interrupt level as well as soft interrupt
659 * level or mainline.
660 * Parameters:
661 *	tty	tty structure
662 *	buf	buffer containing received characters
663 *	cflags	buffer containing error flags for received characters (ignored)
664 *	count	number of received characters
665 */
666static void
667gigaset_tty_receive(struct tty_struct *tty, const unsigned char *buf,
668		    char *cflags, int count)
669{
670	struct cardstate *cs = cs_get(tty);
671	unsigned tail, head, n;
672	struct inbuf_t *inbuf;
673
674	if (!cs)
675		return;
676	inbuf = cs->inbuf;
677	if (!inbuf) {
678		dev_err(cs->dev, "%s: no inbuf\n", __func__);
679		cs_put(cs);
680		return;
681	}
682
683	tail = inbuf->tail;
684	head = inbuf->head;
685	gig_dbg(DEBUG_INTR, "buffer state: %u -> %u, receive %u bytes",
686		head, tail, count);
687
688	if (head <= tail) {
689		/* possible buffer wraparound */
690		n = min_t(unsigned, count, RBUFSIZE - tail);
691		memcpy(inbuf->data + tail, buf, n);
692		tail = (tail + n) % RBUFSIZE;
693		buf += n;
694		count -= n;
695	}
696
697	if (count > 0) {
698		/* tail < head and some data left */
699		n = head - tail - 1;
700		if (count > n) {
701			dev_err(cs->dev,
702				"inbuf overflow, discarding %d bytes\n",
703				count - n);
704			count = n;
705		}
706		memcpy(inbuf->data + tail, buf, count);
707		tail += count;
708	}
709
710	gig_dbg(DEBUG_INTR, "setting tail to %u", tail);
711	inbuf->tail = tail;
712
713	/* Everything was received .. Push data into handler */
714	gig_dbg(DEBUG_INTR, "%s-->BH", __func__);
715	gigaset_schedule_event(cs);
716	cs_put(cs);
717}
718
719/*
720 * Called by the tty driver when there's room for more data to send.
721 */
722static void
723gigaset_tty_wakeup(struct tty_struct *tty)
724{
725	struct cardstate *cs = cs_get(tty);
726
727	clear_bit(TTY_DO_WRITE_WAKEUP, &tty->flags);
728	if (!cs)
729		return;
730	tasklet_schedule(&cs->write_tasklet);
731	cs_put(cs);
732}
733
734static struct tty_ldisc_ops gigaset_ldisc = {
735	.owner		= THIS_MODULE,
736	.magic		= TTY_LDISC_MAGIC,
737	.name		= "ser_gigaset",
738	.open		= gigaset_tty_open,
739	.close		= gigaset_tty_close,
740	.hangup		= gigaset_tty_hangup,
741	.ioctl		= gigaset_tty_ioctl,
742	.receive_buf	= gigaset_tty_receive,
743	.write_wakeup	= gigaset_tty_wakeup,
744};
745
746
747/* Initialization / Shutdown */
748/* ========================= */
749
750static int __init ser_gigaset_init(void)
751{
752	int rc;
753
754	gig_dbg(DEBUG_INIT, "%s", __func__);
755	rc = platform_driver_register(&device_driver);
756	if (rc != 0) {
757		pr_err("error %d registering platform driver\n", rc);
758		return rc;
759	}
760
761	/* allocate memory for our driver state and initialize it */
762	driver = gigaset_initdriver(GIGASET_MINOR, GIGASET_MINORS,
763				    GIGASET_MODULENAME, GIGASET_DEVNAME,
764				    &ops, THIS_MODULE);
765	if (!driver)
766		goto error;
767
768	rc = tty_register_ldisc(N_GIGASET_M101, &gigaset_ldisc);
769	if (rc != 0) {
770		pr_err("error %d registering line discipline\n", rc);
771		goto error;
772	}
773
774	return 0;
775
776error:
777	if (driver) {
778		gigaset_freedriver(driver);
779		driver = NULL;
780	}
781	platform_driver_unregister(&device_driver);
782	return rc;
783}
784
785static void __exit ser_gigaset_exit(void)
786{
787	int rc;
788
789	gig_dbg(DEBUG_INIT, "%s", __func__);
790
791	if (driver) {
792		gigaset_freedriver(driver);
793		driver = NULL;
794	}
795
796	rc = tty_unregister_ldisc(N_GIGASET_M101);
797	if (rc != 0)
798		pr_err("error %d unregistering line discipline\n", rc);
799
800	platform_driver_unregister(&device_driver);
801}
802
803module_init(ser_gigaset_init);
804module_exit(ser_gigaset_exit);
805