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	if (!tty || !tty->driver || !skb)
71		return -EINVAL;
72
73	if (!skb->len) {
74		dev_kfree_skb_any(skb);
75		bcs->tx_skb = NULL;
76		return -EINVAL;
77	}
78
79	set_bit(TTY_DO_WRITE_WAKEUP, &tty->flags);
80	if (tty->ops->write)
81		sent = tty->ops->write(tty, skb->data, skb->len);
82	gig_dbg(DEBUG_OUTPUT, "write_modem: sent %d", sent);
83	if (sent < 0) {
84		/* error */
85		flush_send_queue(cs);
86		return sent;
87	}
88	skb_pull(skb, sent);
89	if (!skb->len) {
90		/* skb sent completely */
91		gigaset_skb_sent(bcs, skb);
92
93		gig_dbg(DEBUG_INTR, "kfree skb (Adr: %lx)!",
94			(unsigned long) skb);
95		dev_kfree_skb_any(skb);
96		bcs->tx_skb = NULL;
97	}
98	return sent;
99}
100
101/*
102 * transmit first queued command buffer
103 * result: number of bytes sent or error code < 0
104 */
105static int send_cb(struct cardstate *cs)
106{
107	struct tty_struct *tty = cs->hw.ser->tty;
108	struct cmdbuf_t *cb, *tcb;
109	unsigned long flags;
110	int sent = 0;
111
112	if (!tty || !tty->driver)
113		return -EFAULT;
114
115	cb = cs->cmdbuf;
116	if (!cb)
117		return 0;	/* nothing to do */
118
119	if (cb->len) {
120		set_bit(TTY_DO_WRITE_WAKEUP, &tty->flags);
121		sent = tty->ops->write(tty, cb->buf + cb->offset, cb->len);
122		if (sent < 0) {
123			/* error */
124			gig_dbg(DEBUG_OUTPUT, "send_cb: write error %d", sent);
125			flush_send_queue(cs);
126			return sent;
127		}
128		cb->offset += sent;
129		cb->len -= sent;
130		gig_dbg(DEBUG_OUTPUT, "send_cb: sent %d, left %u, queued %u",
131			sent, cb->len, cs->cmdbytes);
132	}
133
134	while (cb && !cb->len) {
135		spin_lock_irqsave(&cs->cmdlock, flags);
136		cs->cmdbytes -= cs->curlen;
137		tcb = cb;
138		cs->cmdbuf = cb = cb->next;
139		if (cb) {
140			cb->prev = NULL;
141			cs->curlen = cb->len;
142		} else {
143			cs->lastcmdbuf = NULL;
144			cs->curlen = 0;
145		}
146		spin_unlock_irqrestore(&cs->cmdlock, flags);
147
148		if (tcb->wake_tasklet)
149			tasklet_schedule(tcb->wake_tasklet);
150		kfree(tcb);
151	}
152	return sent;
153}
154
155/*
156 * send queue tasklet
157 * If there is already a skb opened, put data to the transfer buffer
158 * by calling "write_modem".
159 * Otherwise take a new skb out of the queue.
160 */
161static void gigaset_modem_fill(unsigned long data)
162{
163	struct cardstate *cs = (struct cardstate *) data;
164	struct bc_state *bcs;
165	struct sk_buff *nextskb;
166	int sent = 0;
167
168	if (!cs) {
169		gig_dbg(DEBUG_OUTPUT, "%s: no cardstate", __func__);
170		return;
171	}
172	bcs = cs->bcs;
173	if (!bcs) {
174		gig_dbg(DEBUG_OUTPUT, "%s: no cardstate", __func__);
175		return;
176	}
177	if (!bcs->tx_skb) {
178		/* no skb is being sent; send command if any */
179		sent = send_cb(cs);
180		gig_dbg(DEBUG_OUTPUT, "%s: send_cb -> %d", __func__, sent);
181		if (sent)
182			/* something sent or error */
183			return;
184
185		/* no command to send; get skb */
186		nextskb = skb_dequeue(&bcs->squeue);
187		if (!nextskb)
188			/* no skb either, nothing to do */
189			return;
190		bcs->tx_skb = nextskb;
191
192		gig_dbg(DEBUG_INTR, "Dequeued skb (Adr: %lx)",
193			(unsigned long) bcs->tx_skb);
194	}
195
196	/* send skb */
197	gig_dbg(DEBUG_OUTPUT, "%s: tx_skb", __func__);
198	if (write_modem(cs) < 0)
199		gig_dbg(DEBUG_OUTPUT, "%s: write_modem failed", __func__);
200}
201
202/*
203 * throw away all data queued for sending
204 */
205static void flush_send_queue(struct cardstate *cs)
206{
207	struct sk_buff *skb;
208	struct cmdbuf_t *cb;
209	unsigned long flags;
210
211	/* command queue */
212	spin_lock_irqsave(&cs->cmdlock, flags);
213	while ((cb = cs->cmdbuf) != NULL) {
214		cs->cmdbuf = cb->next;
215		if (cb->wake_tasklet)
216			tasklet_schedule(cb->wake_tasklet);
217		kfree(cb);
218	}
219	cs->cmdbuf = cs->lastcmdbuf = NULL;
220	cs->cmdbytes = cs->curlen = 0;
221	spin_unlock_irqrestore(&cs->cmdlock, flags);
222
223	/* data queue */
224	if (cs->bcs->tx_skb)
225		dev_kfree_skb_any(cs->bcs->tx_skb);
226	while ((skb = skb_dequeue(&cs->bcs->squeue)) != NULL)
227		dev_kfree_skb_any(skb);
228}
229
230
231/* Gigaset Driver Interface */
232/* ======================== */
233
234/*
235 * queue an AT command string for transmission to the Gigaset device
236 * parameters:
237 *	cs		controller state structure
238 *	buf		buffer containing the string to send
239 *	len		number of characters to send
240 *	wake_tasklet	tasklet to run when transmission is complete, or NULL
241 * return value:
242 *	number of bytes queued, or error code < 0
243 */
244static int gigaset_write_cmd(struct cardstate *cs, struct cmdbuf_t *cb)
245{
246	unsigned long flags;
247
248	gigaset_dbg_buffer(cs->mstate != MS_LOCKED ?
249			   DEBUG_TRANSCMD : DEBUG_LOCKCMD,
250			   "CMD Transmit", cb->len, cb->buf);
251
252	spin_lock_irqsave(&cs->cmdlock, flags);
253	cb->prev = cs->lastcmdbuf;
254	if (cs->lastcmdbuf)
255		cs->lastcmdbuf->next = cb;
256	else {
257		cs->cmdbuf = cb;
258		cs->curlen = cb->len;
259	}
260	cs->cmdbytes += cb->len;
261	cs->lastcmdbuf = cb;
262	spin_unlock_irqrestore(&cs->cmdlock, flags);
263
264	spin_lock_irqsave(&cs->lock, flags);
265	if (cs->connected)
266		tasklet_schedule(&cs->write_tasklet);
267	spin_unlock_irqrestore(&cs->lock, flags);
268	return cb->len;
269}
270
271/*
272 * tty_driver.write_room interface routine
273 * return number of characters the driver will accept to be written
274 * parameter:
275 *	controller state structure
276 * return value:
277 *	number of characters
278 */
279static int gigaset_write_room(struct cardstate *cs)
280{
281	unsigned bytes;
282
283	bytes = cs->cmdbytes;
284	return bytes < IF_WRITEBUF ? IF_WRITEBUF - bytes : 0;
285}
286
287/*
288 * tty_driver.chars_in_buffer interface routine
289 * return number of characters waiting to be sent
290 * parameter:
291 *	controller state structure
292 * return value:
293 *	number of characters
294 */
295static int gigaset_chars_in_buffer(struct cardstate *cs)
296{
297	return cs->cmdbytes;
298}
299
300/*
301 * implementation of ioctl(GIGASET_BRKCHARS)
302 * parameter:
303 *	controller state structure
304 * return value:
305 *	-EINVAL (unimplemented function)
306 */
307static int gigaset_brkchars(struct cardstate *cs, const unsigned char buf[6])
308{
309	/* not implemented */
310	return -EINVAL;
311}
312
313/*
314 * Open B channel
315 * Called by "do_action" in ev-layer.c
316 */
317static int gigaset_init_bchannel(struct bc_state *bcs)
318{
319	/* nothing to do for M10x */
320	gigaset_bchannel_up(bcs);
321	return 0;
322}
323
324/*
325 * Close B channel
326 * Called by "do_action" in ev-layer.c
327 */
328static int gigaset_close_bchannel(struct bc_state *bcs)
329{
330	/* nothing to do for M10x */
331	gigaset_bchannel_down(bcs);
332	return 0;
333}
334
335/*
336 * Set up B channel structure
337 * This is called by "gigaset_initcs" in common.c
338 */
339static int gigaset_initbcshw(struct bc_state *bcs)
340{
341	/* unused */
342	bcs->hw.ser = NULL;
343	return 1;
344}
345
346/*
347 * Free B channel structure
348 * Called by "gigaset_freebcs" in common.c
349 */
350static int gigaset_freebcshw(struct bc_state *bcs)
351{
352	/* unused */
353	return 1;
354}
355
356/*
357 * Reinitialize B channel structure
358 * This is called by "bcs_reinit" in common.c
359 */
360static void gigaset_reinitbcshw(struct bc_state *bcs)
361{
362	/* nothing to do for M10x */
363}
364
365/*
366 * Free hardware specific device data
367 * This will be called by "gigaset_freecs" in common.c
368 */
369static void gigaset_freecshw(struct cardstate *cs)
370{
371	tasklet_kill(&cs->write_tasklet);
372	if (!cs->hw.ser)
373		return;
374	dev_set_drvdata(&cs->hw.ser->dev.dev, NULL);
375	platform_device_unregister(&cs->hw.ser->dev);
376	kfree(cs->hw.ser);
377	cs->hw.ser = NULL;
378}
379
380static void gigaset_device_release(struct device *dev)
381{
382	struct platform_device *pdev = to_platform_device(dev);
383
384	/* adapted from platform_device_release() in drivers/base/platform.c */
385	kfree(dev->platform_data);
386	kfree(pdev->resource);
387}
388
389/*
390 * Set up hardware specific device data
391 * This is called by "gigaset_initcs" in common.c
392 */
393static int gigaset_initcshw(struct cardstate *cs)
394{
395	int rc;
396	struct ser_cardstate *scs;
397
398	scs = kzalloc(sizeof(struct ser_cardstate), GFP_KERNEL);
399	if (!scs) {
400		pr_err("out of memory\n");
401		return 0;
402	}
403	cs->hw.ser = scs;
404
405	cs->hw.ser->dev.name = GIGASET_MODULENAME;
406	cs->hw.ser->dev.id = cs->minor_index;
407	cs->hw.ser->dev.dev.release = gigaset_device_release;
408	rc = platform_device_register(&cs->hw.ser->dev);
409	if (rc != 0) {
410		pr_err("error %d registering platform device\n", rc);
411		kfree(cs->hw.ser);
412		cs->hw.ser = NULL;
413		return 0;
414	}
415	dev_set_drvdata(&cs->hw.ser->dev.dev, cs);
416
417	tasklet_init(&cs->write_tasklet,
418		     gigaset_modem_fill, (unsigned long) cs);
419	return 1;
420}
421
422/*
423 * set modem control lines
424 * Parameters:
425 *	card state structure
426 *	modem control line state ([TIOCM_DTR]|[TIOCM_RTS])
427 * Called by "gigaset_start" and "gigaset_enterconfigmode" in common.c
428 * and by "if_lock" and "if_termios" in interface.c
429 */
430static int gigaset_set_modem_ctrl(struct cardstate *cs, unsigned old_state,
431				  unsigned new_state)
432{
433	struct tty_struct *tty = cs->hw.ser->tty;
434	unsigned int set, clear;
435
436	if (!tty || !tty->driver || !tty->ops->tiocmset)
437		return -EINVAL;
438	set = new_state & ~old_state;
439	clear = old_state & ~new_state;
440	if (!set && !clear)
441		return 0;
442	gig_dbg(DEBUG_IF, "tiocmset set %x clear %x", set, clear);
443	return tty->ops->tiocmset(tty, set, clear);
444}
445
446static int gigaset_baud_rate(struct cardstate *cs, unsigned cflag)
447{
448	return -EINVAL;
449}
450
451static int gigaset_set_line_ctrl(struct cardstate *cs, unsigned cflag)
452{
453	return -EINVAL;
454}
455
456static const struct gigaset_ops ops = {
457	gigaset_write_cmd,
458	gigaset_write_room,
459	gigaset_chars_in_buffer,
460	gigaset_brkchars,
461	gigaset_init_bchannel,
462	gigaset_close_bchannel,
463	gigaset_initbcshw,
464	gigaset_freebcshw,
465	gigaset_reinitbcshw,
466	gigaset_initcshw,
467	gigaset_freecshw,
468	gigaset_set_modem_ctrl,
469	gigaset_baud_rate,
470	gigaset_set_line_ctrl,
471	gigaset_m10x_send_skb,	/* asyncdata.c */
472	gigaset_m10x_input,	/* asyncdata.c */
473};
474
475
476/* Line Discipline Interface */
477/* ========================= */
478
479/* helper functions for cardstate refcounting */
480static struct cardstate *cs_get(struct tty_struct *tty)
481{
482	struct cardstate *cs = tty->disc_data;
483
484	if (!cs || !cs->hw.ser) {
485		gig_dbg(DEBUG_ANY, "%s: no cardstate", __func__);
486		return NULL;
487	}
488	atomic_inc(&cs->hw.ser->refcnt);
489	return cs;
490}
491
492static void cs_put(struct cardstate *cs)
493{
494	if (atomic_dec_and_test(&cs->hw.ser->refcnt))
495		complete(&cs->hw.ser->dead_cmp);
496}
497
498/*
499 * Called by the tty driver when the line discipline is pushed onto the tty.
500 * Called in process context.
501 */
502static int
503gigaset_tty_open(struct tty_struct *tty)
504{
505	struct cardstate *cs;
506
507	gig_dbg(DEBUG_INIT, "Starting HLL for Gigaset M101");
508
509	pr_info(DRIVER_DESC "\n");
510
511	if (!driver) {
512		pr_err("%s: no driver structure\n", __func__);
513		return -ENODEV;
514	}
515
516	/* allocate memory for our device state and initialize it */
517	cs = gigaset_initcs(driver, 1, 1, 0, cidmode, GIGASET_MODULENAME);
518	if (!cs)
519		goto error;
520
521	cs->dev = &cs->hw.ser->dev.dev;
522	cs->hw.ser->tty = tty;
523	atomic_set(&cs->hw.ser->refcnt, 1);
524	init_completion(&cs->hw.ser->dead_cmp);
525
526	tty->disc_data = cs;
527
528	/* OK.. Initialization of the datastructures and the HW is done.. Now
529	 * startup system and notify the LL that we are ready to run
530	 */
531	if (startmode == SM_LOCKED)
532		cs->mstate = MS_LOCKED;
533	if (!gigaset_start(cs)) {
534		tasklet_kill(&cs->write_tasklet);
535		goto error;
536	}
537
538	gig_dbg(DEBUG_INIT, "Startup of HLL done");
539	return 0;
540
541error:
542	gig_dbg(DEBUG_INIT, "Startup of HLL failed");
543	tty->disc_data = NULL;
544	gigaset_freecs(cs);
545	return -ENODEV;
546}
547
548/*
549 * Called by the tty driver when the line discipline is removed.
550 * Called from process context.
551 */
552static void
553gigaset_tty_close(struct tty_struct *tty)
554{
555	struct cardstate *cs = tty->disc_data;
556
557	gig_dbg(DEBUG_INIT, "Stopping HLL for Gigaset M101");
558
559	if (!cs) {
560		gig_dbg(DEBUG_INIT, "%s: no cardstate", __func__);
561		return;
562	}
563
564	/* prevent other callers from entering ldisc methods */
565	tty->disc_data = NULL;
566
567	if (!cs->hw.ser)
568		pr_err("%s: no hw cardstate\n", __func__);
569	else {
570		/* wait for running methods to finish */
571		if (!atomic_dec_and_test(&cs->hw.ser->refcnt))
572			wait_for_completion(&cs->hw.ser->dead_cmp);
573	}
574
575	/* stop operations */
576	gigaset_stop(cs);
577	tasklet_kill(&cs->write_tasklet);
578	flush_send_queue(cs);
579	cs->dev = NULL;
580	gigaset_freecs(cs);
581
582	gig_dbg(DEBUG_INIT, "Shutdown of HLL done");
583}
584
585/*
586 * Called by the tty driver when the tty line is hung up.
587 * Wait for I/O to driver to complete and unregister ISDN device.
588 * This is already done by the close routine, so just call that.
589 * Called from process context.
590 */
591static int gigaset_tty_hangup(struct tty_struct *tty)
592{
593	gigaset_tty_close(tty);
594	return 0;
595}
596
597/*
598 * Read on the tty.
599 * Unused, received data goes only to the Gigaset driver.
600 */
601static ssize_t
602gigaset_tty_read(struct tty_struct *tty, struct file *file,
603		 unsigned char __user *buf, size_t count)
604{
605	return -EAGAIN;
606}
607
608/*
609 * Write on the tty.
610 * Unused, transmit data comes only from the Gigaset driver.
611 */
612static ssize_t
613gigaset_tty_write(struct tty_struct *tty, struct file *file,
614		  const unsigned char *buf, size_t count)
615{
616	return -EAGAIN;
617}
618
619/*
620 * Ioctl on the tty.
621 * Called in process context only.
622 * May be re-entered by multiple ioctl calling threads.
623 */
624static int
625gigaset_tty_ioctl(struct tty_struct *tty, struct file *file,
626		  unsigned int cmd, unsigned long arg)
627{
628	struct cardstate *cs = cs_get(tty);
629	int rc, val;
630	int __user *p = (int __user *)arg;
631
632	if (!cs)
633		return -ENXIO;
634
635	switch (cmd) {
636
637	case FIONREAD:
638		/* unused, always return zero */
639		val = 0;
640		rc = put_user(val, p);
641		break;
642
643	case TCFLSH:
644		/* flush our buffers and the serial port's buffer */
645		switch (arg) {
646		case TCIFLUSH:
647			/* no own input buffer to flush */
648			break;
649		case TCIOFLUSH:
650		case TCOFLUSH:
651			flush_send_queue(cs);
652			break;
653		}
654		/* Pass through */
655
656	default:
657		/* pass through to underlying serial device */
658		rc = n_tty_ioctl_helper(tty, file, cmd, arg);
659		break;
660	}
661	cs_put(cs);
662	return rc;
663}
664
665/*
666 * Called by the tty driver when a block of data has been received.
667 * Will not be re-entered while running but other ldisc functions
668 * may be called in parallel.
669 * Can be called from hard interrupt level as well as soft interrupt
670 * level or mainline.
671 * Parameters:
672 *	tty	tty structure
673 *	buf	buffer containing received characters
674 *	cflags	buffer containing error flags for received characters (ignored)
675 *	count	number of received characters
676 */
677static void
678gigaset_tty_receive(struct tty_struct *tty, const unsigned char *buf,
679		    char *cflags, int count)
680{
681	struct cardstate *cs = cs_get(tty);
682	unsigned tail, head, n;
683	struct inbuf_t *inbuf;
684
685	if (!cs)
686		return;
687	inbuf = cs->inbuf;
688	if (!inbuf) {
689		dev_err(cs->dev, "%s: no inbuf\n", __func__);
690		cs_put(cs);
691		return;
692	}
693
694	tail = inbuf->tail;
695	head = inbuf->head;
696	gig_dbg(DEBUG_INTR, "buffer state: %u -> %u, receive %u bytes",
697		head, tail, count);
698
699	if (head <= tail) {
700		/* possible buffer wraparound */
701		n = min_t(unsigned, count, RBUFSIZE - tail);
702		memcpy(inbuf->data + tail, buf, n);
703		tail = (tail + n) % RBUFSIZE;
704		buf += n;
705		count -= n;
706	}
707
708	if (count > 0) {
709		/* tail < head and some data left */
710		n = head - tail - 1;
711		if (count > n) {
712			dev_err(cs->dev,
713				"inbuf overflow, discarding %d bytes\n",
714				count - n);
715			count = n;
716		}
717		memcpy(inbuf->data + tail, buf, count);
718		tail += count;
719	}
720
721	gig_dbg(DEBUG_INTR, "setting tail to %u", tail);
722	inbuf->tail = tail;
723
724	/* Everything was received .. Push data into handler */
725	gig_dbg(DEBUG_INTR, "%s-->BH", __func__);
726	gigaset_schedule_event(cs);
727	cs_put(cs);
728}
729
730/*
731 * Called by the tty driver when there's room for more data to send.
732 */
733static void
734gigaset_tty_wakeup(struct tty_struct *tty)
735{
736	struct cardstate *cs = cs_get(tty);
737
738	clear_bit(TTY_DO_WRITE_WAKEUP, &tty->flags);
739	if (!cs)
740		return;
741	tasklet_schedule(&cs->write_tasklet);
742	cs_put(cs);
743}
744
745static struct tty_ldisc_ops gigaset_ldisc = {
746	.owner		= THIS_MODULE,
747	.magic		= TTY_LDISC_MAGIC,
748	.name		= "ser_gigaset",
749	.open		= gigaset_tty_open,
750	.close		= gigaset_tty_close,
751	.hangup		= gigaset_tty_hangup,
752	.read		= gigaset_tty_read,
753	.write		= gigaset_tty_write,
754	.ioctl		= gigaset_tty_ioctl,
755	.receive_buf	= gigaset_tty_receive,
756	.write_wakeup	= gigaset_tty_wakeup,
757};
758
759
760/* Initialization / Shutdown */
761/* ========================= */
762
763static int __init ser_gigaset_init(void)
764{
765	int rc;
766
767	gig_dbg(DEBUG_INIT, "%s", __func__);
768	rc = platform_driver_register(&device_driver);
769	if (rc != 0) {
770		pr_err("error %d registering platform driver\n", rc);
771		return rc;
772	}
773
774	/* allocate memory for our driver state and initialize it */
775	driver = gigaset_initdriver(GIGASET_MINOR, GIGASET_MINORS,
776				    GIGASET_MODULENAME, GIGASET_DEVNAME,
777				    &ops, THIS_MODULE);
778	if (!driver)
779		goto error;
780
781	rc = tty_register_ldisc(N_GIGASET_M101, &gigaset_ldisc);
782	if (rc != 0) {
783		pr_err("error %d registering line discipline\n", rc);
784		goto error;
785	}
786
787	return 0;
788
789error:
790	if (driver) {
791		gigaset_freedriver(driver);
792		driver = NULL;
793	}
794	platform_driver_unregister(&device_driver);
795	return rc;
796}
797
798static void __exit ser_gigaset_exit(void)
799{
800	int rc;
801
802	gig_dbg(DEBUG_INIT, "%s", __func__);
803
804	if (driver) {
805		gigaset_freedriver(driver);
806		driver = NULL;
807	}
808
809	rc = tty_unregister_ldisc(N_GIGASET_M101);
810	if (rc != 0)
811		pr_err("error %d unregistering line discipline\n", rc);
812
813	platform_driver_unregister(&device_driver);
814}
815
816module_init(ser_gigaset_init);
817module_exit(ser_gigaset_exit);
818