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 0;
344}
345
346/*
347 * Free B channel structure
348 * Called by "gigaset_freebcs" in common.c
349 */
350static void gigaset_freebcshw(struct bc_state *bcs)
351{
352	/* unused */
353}
354
355/*
356 * Reinitialize B channel structure
357 * This is called by "bcs_reinit" in common.c
358 */
359static void gigaset_reinitbcshw(struct bc_state *bcs)
360{
361	/* nothing to do for M10x */
362}
363
364/*
365 * Free hardware specific device data
366 * This will be called by "gigaset_freecs" in common.c
367 */
368static void gigaset_freecshw(struct cardstate *cs)
369{
370	tasklet_kill(&cs->write_tasklet);
371	if (!cs->hw.ser)
372		return;
373	dev_set_drvdata(&cs->hw.ser->dev.dev, NULL);
374	platform_device_unregister(&cs->hw.ser->dev);
375	kfree(cs->hw.ser);
376	cs->hw.ser = NULL;
377}
378
379static void gigaset_device_release(struct device *dev)
380{
381	struct platform_device *pdev = to_platform_device(dev);
382
383	/* adapted from platform_device_release() in drivers/base/platform.c */
384	kfree(dev->platform_data);
385	kfree(pdev->resource);
386}
387
388/*
389 * Set up hardware specific device data
390 * This is called by "gigaset_initcs" in common.c
391 */
392static int gigaset_initcshw(struct cardstate *cs)
393{
394	int rc;
395	struct ser_cardstate *scs;
396
397	scs = kzalloc(sizeof(struct ser_cardstate), GFP_KERNEL);
398	if (!scs) {
399		pr_err("out of memory\n");
400		return -ENOMEM;
401	}
402	cs->hw.ser = scs;
403
404	cs->hw.ser->dev.name = GIGASET_MODULENAME;
405	cs->hw.ser->dev.id = cs->minor_index;
406	cs->hw.ser->dev.dev.release = gigaset_device_release;
407	rc = platform_device_register(&cs->hw.ser->dev);
408	if (rc != 0) {
409		pr_err("error %d registering platform device\n", rc);
410		kfree(cs->hw.ser);
411		cs->hw.ser = NULL;
412		return rc;
413	}
414	dev_set_drvdata(&cs->hw.ser->dev.dev, cs);
415
416	tasklet_init(&cs->write_tasklet,
417		     gigaset_modem_fill, (unsigned long) cs);
418	return 0;
419}
420
421/*
422 * set modem control lines
423 * Parameters:
424 *	card state structure
425 *	modem control line state ([TIOCM_DTR]|[TIOCM_RTS])
426 * Called by "gigaset_start" and "gigaset_enterconfigmode" in common.c
427 * and by "if_lock" and "if_termios" in interface.c
428 */
429static int gigaset_set_modem_ctrl(struct cardstate *cs, unsigned old_state,
430				  unsigned new_state)
431{
432	struct tty_struct *tty = cs->hw.ser->tty;
433	unsigned int set, clear;
434
435	if (!tty || !tty->driver || !tty->ops->tiocmset)
436		return -EINVAL;
437	set = new_state & ~old_state;
438	clear = old_state & ~new_state;
439	if (!set && !clear)
440		return 0;
441	gig_dbg(DEBUG_IF, "tiocmset set %x clear %x", set, clear);
442	return tty->ops->tiocmset(tty, set, clear);
443}
444
445static int gigaset_baud_rate(struct cardstate *cs, unsigned cflag)
446{
447	return -EINVAL;
448}
449
450static int gigaset_set_line_ctrl(struct cardstate *cs, unsigned cflag)
451{
452	return -EINVAL;
453}
454
455static const struct gigaset_ops ops = {
456	gigaset_write_cmd,
457	gigaset_write_room,
458	gigaset_chars_in_buffer,
459	gigaset_brkchars,
460	gigaset_init_bchannel,
461	gigaset_close_bchannel,
462	gigaset_initbcshw,
463	gigaset_freebcshw,
464	gigaset_reinitbcshw,
465	gigaset_initcshw,
466	gigaset_freecshw,
467	gigaset_set_modem_ctrl,
468	gigaset_baud_rate,
469	gigaset_set_line_ctrl,
470	gigaset_m10x_send_skb,	/* asyncdata.c */
471	gigaset_m10x_input,	/* asyncdata.c */
472};
473
474
475/* Line Discipline Interface */
476/* ========================= */
477
478/* helper functions for cardstate refcounting */
479static struct cardstate *cs_get(struct tty_struct *tty)
480{
481	struct cardstate *cs = tty->disc_data;
482
483	if (!cs || !cs->hw.ser) {
484		gig_dbg(DEBUG_ANY, "%s: no cardstate", __func__);
485		return NULL;
486	}
487	atomic_inc(&cs->hw.ser->refcnt);
488	return cs;
489}
490
491static void cs_put(struct cardstate *cs)
492{
493	if (atomic_dec_and_test(&cs->hw.ser->refcnt))
494		complete(&cs->hw.ser->dead_cmp);
495}
496
497/*
498 * Called by the tty driver when the line discipline is pushed onto the tty.
499 * Called in process context.
500 */
501static int
502gigaset_tty_open(struct tty_struct *tty)
503{
504	struct cardstate *cs;
505	int rc;
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		rc = -ENODEV;
520		goto error;
521	}
522
523	cs->dev = &cs->hw.ser->dev.dev;
524	cs->hw.ser->tty = tty;
525	atomic_set(&cs->hw.ser->refcnt, 1);
526	init_completion(&cs->hw.ser->dead_cmp);
527	tty->disc_data = cs;
528
529	/* Set the amount of data we're willing to receive per call
530	 * from the hardware driver to half of the input buffer size
531	 * to leave some reserve.
532	 * Note: We don't do flow control towards the hardware driver.
533	 * If more data is received than will fit into the input buffer,
534	 * it will be dropped and an error will be logged. This should
535	 * never happen as the device is slow and the buffer size ample.
536	 */
537	tty->receive_room = RBUFSIZE/2;
538
539	/* OK.. Initialization of the datastructures and the HW is done.. Now
540	 * startup system and notify the LL that we are ready to run
541	 */
542	if (startmode == SM_LOCKED)
543		cs->mstate = MS_LOCKED;
544	rc = gigaset_start(cs);
545	if (rc < 0) {
546		tasklet_kill(&cs->write_tasklet);
547		goto error;
548	}
549
550	gig_dbg(DEBUG_INIT, "Startup of HLL done");
551	return 0;
552
553error:
554	gig_dbg(DEBUG_INIT, "Startup of HLL failed");
555	tty->disc_data = NULL;
556	gigaset_freecs(cs);
557	return rc;
558}
559
560/*
561 * Called by the tty driver when the line discipline is removed.
562 * Called from process context.
563 */
564static void
565gigaset_tty_close(struct tty_struct *tty)
566{
567	struct cardstate *cs = tty->disc_data;
568
569	gig_dbg(DEBUG_INIT, "Stopping HLL for Gigaset M101");
570
571	if (!cs) {
572		gig_dbg(DEBUG_INIT, "%s: no cardstate", __func__);
573		return;
574	}
575
576	/* prevent other callers from entering ldisc methods */
577	tty->disc_data = NULL;
578
579	if (!cs->hw.ser)
580		pr_err("%s: no hw cardstate\n", __func__);
581	else {
582		/* wait for running methods to finish */
583		if (!atomic_dec_and_test(&cs->hw.ser->refcnt))
584			wait_for_completion(&cs->hw.ser->dead_cmp);
585	}
586
587	/* stop operations */
588	gigaset_stop(cs);
589	tasklet_kill(&cs->write_tasklet);
590	flush_send_queue(cs);
591	cs->dev = NULL;
592	gigaset_freecs(cs);
593
594	gig_dbg(DEBUG_INIT, "Shutdown of HLL done");
595}
596
597/*
598 * Called by the tty driver when the tty line is hung up.
599 * Wait for I/O to driver to complete and unregister ISDN device.
600 * This is already done by the close routine, so just call that.
601 * Called from process context.
602 */
603static int gigaset_tty_hangup(struct tty_struct *tty)
604{
605	gigaset_tty_close(tty);
606	return 0;
607}
608
609/*
610 * Read on the tty.
611 * Unused, received data goes only to the Gigaset driver.
612 */
613static ssize_t
614gigaset_tty_read(struct tty_struct *tty, struct file *file,
615		 unsigned char __user *buf, size_t count)
616{
617	return -EAGAIN;
618}
619
620/*
621 * Write on the tty.
622 * Unused, transmit data comes only from the Gigaset driver.
623 */
624static ssize_t
625gigaset_tty_write(struct tty_struct *tty, struct file *file,
626		  const unsigned char *buf, size_t count)
627{
628	return -EAGAIN;
629}
630
631/*
632 * Ioctl on the tty.
633 * Called in process context only.
634 * May be re-entered by multiple ioctl calling threads.
635 */
636static int
637gigaset_tty_ioctl(struct tty_struct *tty, struct file *file,
638		  unsigned int cmd, unsigned long arg)
639{
640	struct cardstate *cs = cs_get(tty);
641	int rc, val;
642	int __user *p = (int __user *)arg;
643
644	if (!cs)
645		return -ENXIO;
646
647	switch (cmd) {
648
649	case FIONREAD:
650		/* unused, always return zero */
651		val = 0;
652		rc = put_user(val, p);
653		break;
654
655	case TCFLSH:
656		/* flush our buffers and the serial port's buffer */
657		switch (arg) {
658		case TCIFLUSH:
659			/* no own input buffer to flush */
660			break;
661		case TCIOFLUSH:
662		case TCOFLUSH:
663			flush_send_queue(cs);
664			break;
665		}
666		/* Pass through */
667
668	default:
669		/* pass through to underlying serial device */
670		rc = n_tty_ioctl_helper(tty, file, cmd, arg);
671		break;
672	}
673	cs_put(cs);
674	return rc;
675}
676
677/*
678 * Called by the tty driver when a block of data has been received.
679 * Will not be re-entered while running but other ldisc functions
680 * may be called in parallel.
681 * Can be called from hard interrupt level as well as soft interrupt
682 * level or mainline.
683 * Parameters:
684 *	tty	tty structure
685 *	buf	buffer containing received characters
686 *	cflags	buffer containing error flags for received characters (ignored)
687 *	count	number of received characters
688 */
689static void
690gigaset_tty_receive(struct tty_struct *tty, const unsigned char *buf,
691		    char *cflags, int count)
692{
693	struct cardstate *cs = cs_get(tty);
694	unsigned tail, head, n;
695	struct inbuf_t *inbuf;
696
697	if (!cs)
698		return;
699	inbuf = cs->inbuf;
700	if (!inbuf) {
701		dev_err(cs->dev, "%s: no inbuf\n", __func__);
702		cs_put(cs);
703		return;
704	}
705
706	tail = inbuf->tail;
707	head = inbuf->head;
708	gig_dbg(DEBUG_INTR, "buffer state: %u -> %u, receive %u bytes",
709		head, tail, count);
710
711	if (head <= tail) {
712		/* possible buffer wraparound */
713		n = min_t(unsigned, count, RBUFSIZE - tail);
714		memcpy(inbuf->data + tail, buf, n);
715		tail = (tail + n) % RBUFSIZE;
716		buf += n;
717		count -= n;
718	}
719
720	if (count > 0) {
721		/* tail < head and some data left */
722		n = head - tail - 1;
723		if (count > n) {
724			dev_err(cs->dev,
725				"inbuf overflow, discarding %d bytes\n",
726				count - n);
727			count = n;
728		}
729		memcpy(inbuf->data + tail, buf, count);
730		tail += count;
731	}
732
733	gig_dbg(DEBUG_INTR, "setting tail to %u", tail);
734	inbuf->tail = tail;
735
736	/* Everything was received .. Push data into handler */
737	gig_dbg(DEBUG_INTR, "%s-->BH", __func__);
738	gigaset_schedule_event(cs);
739	cs_put(cs);
740}
741
742/*
743 * Called by the tty driver when there's room for more data to send.
744 */
745static void
746gigaset_tty_wakeup(struct tty_struct *tty)
747{
748	struct cardstate *cs = cs_get(tty);
749
750	clear_bit(TTY_DO_WRITE_WAKEUP, &tty->flags);
751	if (!cs)
752		return;
753	tasklet_schedule(&cs->write_tasklet);
754	cs_put(cs);
755}
756
757static struct tty_ldisc_ops gigaset_ldisc = {
758	.owner		= THIS_MODULE,
759	.magic		= TTY_LDISC_MAGIC,
760	.name		= "ser_gigaset",
761	.open		= gigaset_tty_open,
762	.close		= gigaset_tty_close,
763	.hangup		= gigaset_tty_hangup,
764	.read		= gigaset_tty_read,
765	.write		= gigaset_tty_write,
766	.ioctl		= gigaset_tty_ioctl,
767	.receive_buf	= gigaset_tty_receive,
768	.write_wakeup	= gigaset_tty_wakeup,
769};
770
771
772/* Initialization / Shutdown */
773/* ========================= */
774
775static int __init ser_gigaset_init(void)
776{
777	int rc;
778
779	gig_dbg(DEBUG_INIT, "%s", __func__);
780	rc = platform_driver_register(&device_driver);
781	if (rc != 0) {
782		pr_err("error %d registering platform driver\n", rc);
783		return rc;
784	}
785
786	/* allocate memory for our driver state and initialize it */
787	driver = gigaset_initdriver(GIGASET_MINOR, GIGASET_MINORS,
788				    GIGASET_MODULENAME, GIGASET_DEVNAME,
789				    &ops, THIS_MODULE);
790	if (!driver)
791		goto error;
792
793	rc = tty_register_ldisc(N_GIGASET_M101, &gigaset_ldisc);
794	if (rc != 0) {
795		pr_err("error %d registering line discipline\n", rc);
796		goto error;
797	}
798
799	return 0;
800
801error:
802	if (driver) {
803		gigaset_freedriver(driver);
804		driver = NULL;
805	}
806	platform_driver_unregister(&device_driver);
807	return rc;
808}
809
810static void __exit ser_gigaset_exit(void)
811{
812	int rc;
813
814	gig_dbg(DEBUG_INIT, "%s", __func__);
815
816	if (driver) {
817		gigaset_freedriver(driver);
818		driver = NULL;
819	}
820
821	rc = tty_unregister_ldisc(N_GIGASET_M101);
822	if (rc != 0)
823		pr_err("error %d unregistering line discipline\n", rc);
824
825	platform_driver_unregister(&device_driver);
826}
827
828module_init(ser_gigaset_init);
829module_exit(ser_gigaset_exit);
830