summaryrefslogtreecommitdiff
path: root/drivers/tty/serial/max3100.c
blob: e238e80cd98143d1a6c988afaca525a7c478ccb3 (plain)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
262
263
264
265
266
267
268
269
270
271
272
273
274
275
276
277
278
279
280
281
282
283
284
285
286
287
288
289
290
291
292
293
294
295
296
297
298
299
300
301
302
303
304
305
306
307
308
309
310
311
312
313
314
315
316
317
318
319
320
321
322
323
324
325
326
327
328
329
330
331
332
333
334
335
336
337
338
339
340
341
342
343
344
345
346
347
348
349
350
351
352
353
354
355
356
357
358
359
360
361
362
363
364
365
366
367
368
369
370
371
372
373
374
375
376
377
378
379
380
381
382
383
384
385
386
387
388
389
390
391
392
393
394
395
396
397
398
399
400
401
402
403
404
405
406
407
408
409
410
411
412
413
414
415
416
417
418
419
420
421
422
423
424
425
426
427
428
429
430
431
432
433
434
435
436
437
438
439
440
441
442
443
444
445
446
447
448
449
450
451
452
453
454
455
456
457
458
459
460
461
462
463
464
465
466
467
468
469
470
471
472
473
474
475
476
477
478
479
480
481
482
483
484
485
486
487
488
489
490
491
492
493
494
495
496
497
498
499
500
501
502
503
504
505
506
507
508
509
510
511
512
513
514
515
516
517
518
519
520
521
522
523
524
525
526
527
528
529
530
531
532
533
534
535
536
537
538
539
540
541
542
543
544
545
546
547
548
549
550
551
552
553
554
555
556
557
558
559
560
561
562
563
564
565
566
567
568
569
570
571
572
573
574
575
576
577
578
579
580
581
582
583
584
585
586
587
588
589
590
591
592
593
594
595
596
597
598
599
600
601
602
603
604
605
606
607
608
609
610
611
612
613
614
615
616
617
618
619
620
621
622
623
624
625
626
627
628
629
630
631
632
633
634
635
636
637
638
639
640
641
642
643
644
645
646
647
648
649
650
651
652
653
654
655
656
657
658
659
660
661
662
663
664
665
666
667
668
669
670
671
672
673
674
675
676
677
678
679
680
681
682
683
684
685
686
687
688
689
690
691
692
693
694
695
696
697
698
699
700
701
702
703
704
705
706
707
708
709
710
711
712
713
714
715
716
717
718
719
720
721
722
723
724
725
726
727
728
729
730
731
732
733
734
735
736
737
738
739
740
741
742
743
744
745
746
747
748
749
750
751
752
753
754
755
756
757
758
759
760
761
762
763
764
765
766
767
768
769
770
771
772
773
774
775
776
777
778
779
780
781
782
783
784
785
786
787
788
789
790
791
792
793
794
795
796
797
798
799
800
801
802
803
804
805
806
807
808
809
810
811
812
813
814
815
816
817
818
819
820
821
822
823
824
825
826
827
828
829
830
831
832
833
834
835
836
837
838
839
840
841
842
843
844
845
846
847
848
849
850
851
852
853
854
855
856
857
858
859
860
861
862
863
864
865
866
867
868
869
870
871
872
873
874
875
876
877
878
879
880
881
882
883
884
885
886
887
888
889
890
891
892
893
894
895
896
897
898
899
900
901
902
903
904
905
906
907
908
909
910
911
912
913
914
915
916
917
918
919
920
/*
 *
 *  Copyright (C) 2008 Christian Pellegrin <chripell@evolware.org>
 *
 * This program is free software; you can redistribute it and/or modify
 * it under the terms of the GNU General Public License as published by
 * the Free Software Foundation; either version 2 of the License, or
 * (at your option) any later version.
 *
 *
 * Notes: the MAX3100 doesn't provide an interrupt on CTS so we have
 * to use polling for flow control. TX empty IRQ is unusable, since
 * writing conf clears FIFO buffer and we cannot have this interrupt
 * always asking us for attention.
 *
 * Example platform data:

 static struct plat_max3100 max3100_plat_data = {
 .loopback = 0,
 .crystal = 0,
 .poll_time = 100,
 };

 static struct spi_board_info spi_board_info[] = {
 {
 .modalias	= "max3100",
 .platform_data	= &max3100_plat_data,
 .irq		= IRQ_EINT12,
 .max_speed_hz	= 5*1000*1000,
 .chip_select	= 0,
 },
 };

 * The initial minor number is 209 in the low-density serial port:
 * mknod /dev/ttyMAX0 c 204 209
 */

#define MAX3100_MAJOR 204
#define MAX3100_MINOR 209
/* 4 MAX3100s should be enough for everyone */
#define MAX_MAX3100 4

#include <linux/delay.h>
#include <linux/slab.h>
#include <linux/device.h>
#include <linux/module.h>
#include <linux/serial_core.h>
#include <linux/serial.h>
#include <linux/spi/spi.h>
#include <linux/freezer.h>
#include <linux/tty.h>
#include <linux/tty_flip.h>

#include <linux/serial_max3100.h>

#define MAX3100_C    (1<<14)
#define MAX3100_D    (0<<14)
#define MAX3100_W    (1<<15)
#define MAX3100_RX   (0<<15)

#define MAX3100_WC   (MAX3100_W  | MAX3100_C)
#define MAX3100_RC   (MAX3100_RX | MAX3100_C)
#define MAX3100_WD   (MAX3100_W  | MAX3100_D)
#define MAX3100_RD   (MAX3100_RX | MAX3100_D)
#define MAX3100_CMD  (3 << 14)

#define MAX3100_T    (1<<14)
#define MAX3100_R    (1<<15)

#define MAX3100_FEN  (1<<13)
#define MAX3100_SHDN (1<<12)
#define MAX3100_TM   (1<<11)
#define MAX3100_RM   (1<<10)
#define MAX3100_PM   (1<<9)
#define MAX3100_RAM  (1<<8)
#define MAX3100_IR   (1<<7)
#define MAX3100_ST   (1<<6)
#define MAX3100_PE   (1<<5)
#define MAX3100_L    (1<<4)
#define MAX3100_BAUD (0xf)

#define MAX3100_TE   (1<<10)
#define MAX3100_RAFE (1<<10)
#define MAX3100_RTS  (1<<9)
#define MAX3100_CTS  (1<<9)
#define MAX3100_PT   (1<<8)
#define MAX3100_DATA (0xff)

#define MAX3100_RT   (MAX3100_R | MAX3100_T)
#define MAX3100_RTC  (MAX3100_RT | MAX3100_CTS | MAX3100_RAFE)

/* the following simulate a status reg for ignore_status_mask */
#define MAX3100_STATUS_PE 1
#define MAX3100_STATUS_FE 2
#define MAX3100_STATUS_OE 4

struct max3100_port {
	struct uart_port port;
	struct spi_device *spi;

	int cts;	        /* last CTS received for flow ctrl */
	int tx_empty;		/* last TX empty bit */

	spinlock_t conf_lock;	/* shared data */
	int conf_commit;	/* need to make changes */
	int conf;		/* configuration for the MAX31000
				 * (bits 0-7, bits 8-11 are irqs) */
	int rts_commit;	        /* need to change rts */
	int rts;		/* rts status */
	int baud;		/* current baud rate */

	int parity;		/* keeps track if we should send parity */
#define MAX3100_PARITY_ON 1
#define MAX3100_PARITY_ODD 2
#define MAX3100_7BIT 4
	int rx_enabled;	        /* if we should rx chars */

	int irq;		/* irq assigned to the max3100 */

	int minor;		/* minor number */
	int crystal;		/* 1 if 3.6864Mhz crystal 0 for 1.8432 */
	int loopback;		/* 1 if we are in loopback mode */

	/* for handling irqs: need workqueue since we do spi_sync */
	struct workqueue_struct *workqueue;
	struct work_struct work;
	/* set to 1 to make the workhandler exit as soon as possible */
	int  force_end_work;
	/* need to know we are suspending to avoid deadlock on workqueue */
	int suspending;

	/* hook for suspending MAX3100 via dedicated pin */
	void (*max3100_hw_suspend) (int suspend);

	/* poll time (in ms) for ctrl lines */
	int poll_time;
	/* and its timer */
	struct timer_list	timer;
};

static struct max3100_port *max3100s[MAX_MAX3100]; /* the chips */
static DEFINE_MUTEX(max3100s_lock);		   /* race on probe */

static int max3100_do_parity(struct max3100_port *s, u16 c)
{
	int parity;

	if (s->parity & MAX3100_PARITY_ODD)
		parity = 1;
	else
		parity = 0;

	if (s->parity & MAX3100_7BIT)
		c &= 0x7f;
	else
		c &= 0xff;

	parity = parity ^ (hweight8(c) & 1);
	return parity;
}

static int max3100_check_parity(struct max3100_port *s, u16 c)
{
	return max3100_do_parity(s, c) == ((c >> 8) & 1);
}

static void max3100_calc_parity(struct max3100_port *s, u16 *c)
{
	if (s->parity & MAX3100_7BIT)
		*c &= 0x7f;
	else
		*c &= 0xff;

	if (s->parity & MAX3100_PARITY_ON)
		*c |= max3100_do_parity(s, *c) << 8;
}

static void max3100_work(struct work_struct *w);

static void max3100_dowork(struct max3100_port *s)
{
	if (!s->force_end_work && !work_pending(&s->work) &&
	    !freezing(current) && !s->suspending)
		queue_work(s->workqueue, &s->work);
}

static void max3100_timeout(unsigned long data)
{
	struct max3100_port *s = (struct max3100_port *)data;

	if (s->port.state) {
		max3100_dowork(s);
		mod_timer(&s->timer, jiffies + s->poll_time);
	}
}

static int max3100_sr(struct max3100_port *s, u16 tx, u16 *rx)
{
	struct spi_message message;
	u16 etx, erx;
	int status;
	struct spi_transfer tran = {
		.tx_buf = &etx,
		.rx_buf = &erx,
		.len = 2,
	};

	etx = cpu_to_be16(tx);
	spi_message_init(&message);
	spi_message_add_tail(&tran, &message);
	status = spi_sync(s->spi, &message);
	if (status) {
		dev_warn(&s->spi->dev, "error while calling spi_sync\n");
		return -EIO;
	}
	*rx = be16_to_cpu(erx);
	s->tx_empty = (*rx & MAX3100_T) > 0;
	dev_dbg(&s->spi->dev, "%04x - %04x\n", tx, *rx);
	return 0;
}

static int max3100_handlerx(struct max3100_port *s, u16 rx)
{
	unsigned int ch, flg, status = 0;
	int ret = 0, cts;

	if (rx & MAX3100_R && s->rx_enabled) {
		dev_dbg(&s->spi->dev, "%s\n", __func__);
		ch = rx & (s->parity & MAX3100_7BIT ? 0x7f : 0xff);
		if (rx & MAX3100_RAFE) {
			s->port.icount.frame++;
			flg = TTY_FRAME;
			status |= MAX3100_STATUS_FE;
		} else {
			if (s->parity & MAX3100_PARITY_ON) {
				if (max3100_check_parity(s, rx)) {
					s->port.icount.rx++;
					flg = TTY_NORMAL;
				} else {
					s->port.icount.parity++;
					flg = TTY_PARITY;
					status |= MAX3100_STATUS_PE;
				}
			} else {
				s->port.icount.rx++;
				flg = TTY_NORMAL;
			}
		}
		uart_insert_char(&s->port, status, MAX3100_STATUS_OE, ch, flg);
		ret = 1;
	}

	cts = (rx & MAX3100_CTS) > 0;
	if (s->cts != cts) {
		s->cts = cts;
		uart_handle_cts_change(&s->port, cts ? TIOCM_CTS : 0);
	}

	return ret;
}

static void max3100_work(struct work_struct *w)
{
	struct max3100_port *s = container_of(w, struct max3100_port, work);
	int rxchars;
	u16 tx, rx;
	int conf, cconf, rts, crts;
	struct circ_buf *xmit = &s->port.state->xmit;

	dev_dbg(&s->spi->dev, "%s\n", __func__);

	rxchars = 0;
	do {
		spin_lock(&s->conf_lock);
		conf = s->conf;
		cconf = s->conf_commit;
		s->conf_commit = 0;
		rts = s->rts;
		crts = s->rts_commit;
		s->rts_commit = 0;
		spin_unlock(&s->conf_lock);
		if (cconf)
			max3100_sr(s, MAX3100_WC | conf, &rx);
		if (crts) {
			max3100_sr(s, MAX3100_WD | MAX3100_TE |
				   (s->rts ? MAX3100_RTS : 0), &rx);
			rxchars += max3100_handlerx(s, rx);
		}

		max3100_sr(s, MAX3100_RD, &rx);
		rxchars += max3100_handlerx(s, rx);

		if (rx & MAX3100_T) {
			tx = 0xffff;
			if (s->port.x_char) {
				tx = s->port.x_char;
				s->port.icount.tx++;
				s->port.x_char = 0;
			} else if (!uart_circ_empty(xmit) &&
				   !uart_tx_stopped(&s->port)) {
				tx = xmit->buf[xmit->tail];
				xmit->tail = (xmit->tail + 1) &
					(UART_XMIT_SIZE - 1);
				s->port.icount.tx++;
			}
			if (tx != 0xffff) {
				max3100_calc_parity(s, &tx);
				tx |= MAX3100_WD | (s->rts ? MAX3100_RTS : 0);
				max3100_sr(s, tx, &rx);
				rxchars += max3100_handlerx(s, rx);
			}
		}

		if (rxchars > 16 && s->port.state->port.tty != NULL) {
			tty_flip_buffer_push(s->port.state->port.tty);
			rxchars = 0;
		}
		if (uart_circ_chars_pending(xmit) < WAKEUP_CHARS)
			uart_write_wakeup(&s->port);

	} while (!s->force_end_work &&
		 !freezing(current) &&
		 ((rx & MAX3100_R) ||
		  (!uart_circ_empty(xmit) &&
		   !uart_tx_stopped(&s->port))));

	if (rxchars > 0 && s->port.state->port.tty != NULL)
		tty_flip_buffer_push(s->port.state->port.tty);
}

static irqreturn_t max3100_irq(int irqno, void *dev_id)
{
	struct max3100_port *s = dev_id;

	dev_dbg(&s->spi->dev, "%s\n", __func__);

	max3100_dowork(s);
	return IRQ_HANDLED;
}

static void max3100_enable_ms(struct uart_port *port)
{
	struct max3100_port *s = container_of(port,
					      struct max3100_port,
					      port);

	if (s->poll_time > 0)
		mod_timer(&s->timer, jiffies);
	dev_dbg(&s->spi->dev, "%s\n", __func__);
}

static void max3100_start_tx(struct uart_port *port)
{
	struct max3100_port *s = container_of(port,
					      struct max3100_port,
					      port);

	dev_dbg(&s->spi->dev, "%s\n", __func__);

	max3100_dowork(s);
}

static void max3100_stop_rx(struct uart_port *port)
{
	struct max3100_port *s = container_of(port,
					      struct max3100_port,
					      port);

	dev_dbg(&s->spi->dev, "%s\n", __func__);

	s->rx_enabled = 0;
	spin_lock(&s->conf_lock);
	s->conf &= ~MAX3100_RM;
	s->conf_commit = 1;
	spin_unlock(&s->conf_lock);
	max3100_dowork(s);
}

static unsigned int max3100_tx_empty(struct uart_port *port)
{
	struct max3100_port *s = container_of(port,
					      struct max3100_port,
					      port);

	dev_dbg(&s->spi->dev, "%s\n", __func__);

	/* may not be truly up-to-date */
	max3100_dowork(s);
	return s->tx_empty;
}

static unsigned int max3100_get_mctrl(struct uart_port *port)
{
	struct max3100_port *s = container_of(port,
					      struct max3100_port,
					      port);

	dev_dbg(&s->spi->dev, "%s\n", __func__);

	/* may not be truly up-to-date */
	max3100_dowork(s);
	/* always assert DCD and DSR since these lines are not wired */
	return (s->cts ? TIOCM_CTS : 0) | TIOCM_DSR | TIOCM_CAR;
}

static void max3100_set_mctrl(struct uart_port *port, unsigned int mctrl)
{
	struct max3100_port *s = container_of(port,
					      struct max3100_port,
					      port);
	int rts;

	dev_dbg(&s->spi->dev, "%s\n", __func__);

	rts = (mctrl & TIOCM_RTS) > 0;

	spin_lock(&s->conf_lock);
	if (s->rts != rts) {
		s->rts = rts;
		s->rts_commit = 1;
		max3100_dowork(s);
	}
	spin_unlock(&s->conf_lock);
}

static void
max3100_set_termios(struct uart_port *port, struct ktermios *termios,
		    struct ktermios *old)
{
	struct max3100_port *s = container_of(port,
					      struct max3100_port,
					      port);
	int baud = 0;
	unsigned cflag;
	u32 param_new, param_mask, parity = 0;

	dev_dbg(&s->spi->dev, "%s\n", __func__);

	cflag = termios->c_cflag;
	param_new = 0;
	param_mask = 0;

	baud = tty_termios_baud_rate(termios);
	param_new = s->conf & MAX3100_BAUD;
	switch (baud) {
	case 300:
		if (s->crystal)
			baud = s->baud;
		else
			param_new = 15;
		break;
	case 600:
		param_new = 14 + s->crystal;
		break;
	case 1200:
		param_new = 13 + s->crystal;
		break;
	case 2400:
		param_new = 12 + s->crystal;
		break;
	case 4800:
		param_new = 11 + s->crystal;
		break;
	case 9600:
		param_new = 10 + s->crystal;
		break;
	case 19200:
		param_new = 9 + s->crystal;
		break;
	case 38400:
		param_new = 8 + s->crystal;
		break;
	case 57600:
		param_new = 1 + s->crystal;
		break;
	case 115200:
		param_new = 0 + s->crystal;
		break;
	case 230400:
		if (s->crystal)
			param_new = 0;
		else
			baud = s->baud;
		break;
	default:
		baud = s->baud;
	}
	tty_termios_encode_baud_rate(termios, baud, baud);
	s->baud = baud;
	param_mask |= MAX3100_BAUD;

	if ((cflag & CSIZE) == CS8) {
		param_new &= ~MAX3100_L;
		parity &= ~MAX3100_7BIT;
	} else {
		param_new |= MAX3100_L;
		parity |= MAX3100_7BIT;
		cflag = (cflag & ~CSIZE) | CS7;
	}
	param_mask |= MAX3100_L;

	if (cflag & CSTOPB)
		param_new |= MAX3100_ST;
	else
		param_new &= ~MAX3100_ST;
	param_mask |= MAX3100_ST;

	if (cflag & PARENB) {
		param_new |= MAX3100_PE;
		parity |= MAX3100_PARITY_ON;
	} else {
		param_new &= ~MAX3100_PE;
		parity &= ~MAX3100_PARITY_ON;
	}
	param_mask |= MAX3100_PE;

	if (cflag & PARODD)
		parity |= MAX3100_PARITY_ODD;
	else
		parity &= ~MAX3100_PARITY_ODD;

	/* mask termios capabilities we don't support */
	cflag &= ~CMSPAR;
	termios->c_cflag = cflag;

	s->port.ignore_status_mask = 0;
	if (termios->c_iflag & IGNPAR)
		s->port.ignore_status_mask |=
			MAX3100_STATUS_PE | MAX3100_STATUS_FE |
			MAX3100_STATUS_OE;

	/* we are sending char from a workqueue so enable */
	s->port.state->port.low_latency = 1;

	if (s->poll_time > 0)
		del_timer_sync(&s->timer);

	uart_update_timeout(port, termios->c_cflag, baud);

	spin_lock(&s->conf_lock);
	s->conf = (s->conf & ~param_mask) | (param_new & param_mask);
	s->conf_commit = 1;
	s->parity = parity;
	spin_unlock(&s->conf_lock);
	max3100_dowork(s);

	if (UART_ENABLE_MS(&s->port, termios->c_cflag))
		max3100_enable_ms(&s->port);
}

static void max3100_shutdown(struct uart_port *port)
{
	struct max3100_port *s = container_of(port,
					      struct max3100_port,
					      port);

	dev_dbg(&s->spi->dev, "%s\n", __func__);

	if (s->suspending)
		return;

	s->force_end_work = 1;

	if (s->poll_time > 0)
		del_timer_sync(&s->timer);

	if (s->workqueue) {
		flush_workqueue(s->workqueue);
		destroy_workqueue(s->workqueue);
		s->workqueue = NULL;
	}
	if (s->irq)
		free_irq(s->irq, s);

	/* set shutdown mode to save power */
	if (s->max3100_hw_suspend)
		s->max3100_hw_suspend(1);
	else  {
		u16 tx, rx;

		tx = MAX3100_WC | MAX3100_SHDN;
		max3100_sr(s, tx, &rx);
	}
}

static int max3100_startup(struct uart_port *port)
{
	struct max3100_port *s = container_of(port,
					      struct max3100_port,
					      port);
	char b[12];

	dev_dbg(&s->spi->dev, "%s\n", __func__);

	s->conf = MAX3100_RM;
	s->baud = s->crystal ? 230400 : 115200;
	s->rx_enabled = 1;

	if (s->suspending)
		return 0;

	s->force_end_work = 0;
	s->parity = 0;
	s->rts = 0;

	sprintf(b, "max3100-%d", s->minor);
	s->workqueue = create_freezable_workqueue(b);
	if (!s->workqueue) {
		dev_warn(&s->spi->dev, "cannot create workqueue\n");
		return -EBUSY;
	}
	INIT_WORK(&s->work, max3100_work);

	if (request_irq(s->irq, max3100_irq,
			IRQF_TRIGGER_FALLING, "max3100", s) < 0) {
		dev_warn(&s->spi->dev, "cannot allocate irq %d\n", s->irq);
		s->irq = 0;
		destroy_workqueue(s->workqueue);
		s->workqueue = NULL;
		return -EBUSY;
	}

	if (s->loopback) {
		u16 tx, rx;
		tx = 0x4001;
		max3100_sr(s, tx, &rx);
	}

	if (s->max3100_hw_suspend)
		s->max3100_hw_suspend(0);
	s->conf_commit = 1;
	max3100_dowork(s);
	/* wait for clock to settle */
	msleep(50);

	max3100_enable_ms(&s->port);

	return 0;
}

static const char *max3100_type(struct uart_port *port)
{
	struct max3100_port *s = container_of(port,
					      struct max3100_port,
					      port);

	dev_dbg(&s->spi->dev, "%s\n", __func__);

	return s->port.type == PORT_MAX3100 ? "MAX3100" : NULL;
}

static void max3100_release_port(struct uart_port *port)
{
	struct max3100_port *s = container_of(port,
					      struct max3100_port,
					      port);

	dev_dbg(&s->spi->dev, "%s\n", __func__);
}

static void max3100_config_port(struct uart_port *port, int flags)
{
	struct max3100_port *s = container_of(port,
					      struct max3100_port,
					      port);

	dev_dbg(&s->spi->dev, "%s\n", __func__);

	if (flags & UART_CONFIG_TYPE)
		s->port.type = PORT_MAX3100;
}

static int max3100_verify_port(struct uart_port *port,
			       struct serial_struct *ser)
{
	struct max3100_port *s = container_of(port,
					      struct max3100_port,
					      port);
	int ret = -EINVAL;

	dev_dbg(&s->spi->dev, "%s\n", __func__);

	if (ser->type == PORT_UNKNOWN || ser->type == PORT_MAX3100)
		ret = 0;
	return ret;
}

static void max3100_stop_tx(struct uart_port *port)
{
	struct max3100_port *s = container_of(port,
					      struct max3100_port,
					      port);

	dev_dbg(&s->spi->dev, "%s\n", __func__);
}

static int max3100_request_port(struct uart_port *port)
{
	struct max3100_port *s = container_of(port,
					      struct max3100_port,
					      port);

	dev_dbg(&s->spi->dev, "%s\n", __func__);
	return 0;
}

static void max3100_break_ctl(struct uart_port *port, int break_state)
{
	struct max3100_port *s = container_of(port,
					      struct max3100_port,
					      port);

	dev_dbg(&s->spi->dev, "%s\n", __func__);
}

static struct uart_ops max3100_ops = {
	.tx_empty	= max3100_tx_empty,
	.set_mctrl	= max3100_set_mctrl,
	.get_mctrl	= max3100_get_mctrl,
	.stop_tx        = max3100_stop_tx,
	.start_tx	= max3100_start_tx,
	.stop_rx	= max3100_stop_rx,
	.enable_ms      = max3100_enable_ms,
	.break_ctl      = max3100_break_ctl,
	.startup	= max3100_startup,
	.shutdown	= max3100_shutdown,
	.set_termios	= max3100_set_termios,
	.type		= max3100_type,
	.release_port   = max3100_release_port,
	.request_port   = max3100_request_port,
	.config_port	= max3100_config_port,
	.verify_port	= max3100_verify_port,
};

static struct uart_driver max3100_uart_driver = {
	.owner          = THIS_MODULE,
	.driver_name    = "ttyMAX",
	.dev_name       = "ttyMAX",
	.major          = MAX3100_MAJOR,
	.minor          = MAX3100_MINOR,
	.nr             = MAX_MAX3100,
};
static int uart_driver_registered;

static int max3100_probe(struct spi_device *spi)
{
	int i, retval;
	struct plat_max3100 *pdata;
	u16 tx, rx;

	mutex_lock(&max3100s_lock);

	if (!uart_driver_registered) {
		uart_driver_registered = 1;
		retval = uart_register_driver(&max3100_uart_driver);
		if (retval) {
			printk(KERN_ERR "Couldn't register max3100 uart driver\n");
			mutex_unlock(&max3100s_lock);
			return retval;
		}
	}

	for (i = 0; i < MAX_MAX3100; i++)
		if (!max3100s[i])
			break;
	if (i == MAX_MAX3100) {
		dev_warn(&spi->dev, "too many MAX3100 chips\n");
		mutex_unlock(&max3100s_lock);
		return -ENOMEM;
	}

	max3100s[i] = kzalloc(sizeof(struct max3100_port), GFP_KERNEL);
	if (!max3100s[i]) {
		dev_warn(&spi->dev,
			 "kmalloc for max3100 structure %d failed!\n", i);
		mutex_unlock(&max3100s_lock);
		return -ENOMEM;
	}
	max3100s[i]->spi = spi;
	max3100s[i]->irq = spi->irq;
	spin_lock_init(&max3100s[i]->conf_lock);
	dev_set_drvdata(&spi->dev, max3100s[i]);
	pdata = spi->dev.platform_data;
	max3100s[i]->crystal = pdata->crystal;
	max3100s[i]->loopback = pdata->loopback;
	max3100s[i]->poll_time = pdata->poll_time * HZ / 1000;
	if (pdata->poll_time > 0 && max3100s[i]->poll_time == 0)
		max3100s[i]->poll_time = 1;
	max3100s[i]->max3100_hw_suspend = pdata->max3100_hw_suspend;
	max3100s[i]->minor = i;
	init_timer(&max3100s[i]->timer);
	max3100s[i]->timer.function = max3100_timeout;
	max3100s[i]->timer.data = (unsigned long) max3100s[i];

	dev_dbg(&spi->dev, "%s: adding port %d\n", __func__, i);
	max3100s[i]->port.irq = max3100s[i]->irq;
	max3100s[i]->port.uartclk = max3100s[i]->crystal ? 3686400 : 1843200;
	max3100s[i]->port.fifosize = 16;
	max3100s[i]->port.ops = &max3100_ops;
	max3100s[i]->port.flags = UPF_SKIP_TEST | UPF_BOOT_AUTOCONF;
	max3100s[i]->port.line = i;
	max3100s[i]->port.type = PORT_MAX3100;
	max3100s[i]->port.dev = &spi->dev;
	retval = uart_add_one_port(&max3100_uart_driver, &max3100s[i]->port);
	if (retval < 0)
		dev_warn(&spi->dev,
			 "uart_add_one_port failed for line %d with error %d\n",
			 i, retval);

	/* set shutdown mode to save power. Will be woken-up on open */
	if (max3100s[i]->max3100_hw_suspend)
		max3100s[i]->max3100_hw_suspend(1);
	else {
		tx = MAX3100_WC | MAX3100_SHDN;
		max3100_sr(max3100s[i], tx, &rx);
	}
	mutex_unlock(&max3100s_lock);
	return 0;
}

static int max3100_remove(struct spi_device *spi)
{
	struct max3100_port *s = dev_get_drvdata(&spi->dev);
	int i;

	mutex_lock(&max3100s_lock);

	/* find out the index for the chip we are removing */
	for (i = 0; i < MAX_MAX3100; i++)
		if (max3100s[i] == s) {
			dev_dbg(&spi->dev, "%s: removing port %d\n", __func__, i);
			uart_remove_one_port(&max3100_uart_driver, &max3100s[i]->port);
			kfree(max3100s[i]);
			max3100s[i] = NULL;
			break;
		}

	WARN_ON(i == MAX_MAX3100);
	
	/* check if this is the last chip we have */
	for (i = 0; i < MAX_MAX3100; i++)
		if (max3100s[i]) {
			mutex_unlock(&max3100s_lock);
			return 0;
		}
	pr_debug("removing max3100 driver\n");
	uart_unregister_driver(&max3100_uart_driver);

	mutex_unlock(&max3100s_lock);
	return 0;
}

#ifdef CONFIG_PM

static int max3100_suspend(struct spi_device *spi, pm_message_t state)
{
	struct max3100_port *s = dev_get_drvdata(&spi->dev);

	dev_dbg(&s->spi->dev, "%s\n", __func__);

	disable_irq(s->irq);

	s->suspending = 1;
	uart_suspend_port(&max3100_uart_driver, &s->port);

	if (s->max3100_hw_suspend)
		s->max3100_hw_suspend(1);
	else {
		/* no HW suspend, so do SW one */
		u16 tx, rx;

		tx = MAX3100_WC | MAX3100_SHDN;
		max3100_sr(s, tx, &rx);
	}
	return 0;
}

static int max3100_resume(struct spi_device *spi)
{
	struct max3100_port *s = dev_get_drvdata(&spi->dev);

	dev_dbg(&s->spi->dev, "%s\n", __func__);

	if (s->max3100_hw_suspend)
		s->max3100_hw_suspend(0);
	uart_resume_port(&max3100_uart_driver, &s->port);
	s->suspending = 0;

	enable_irq(s->irq);

	s->conf_commit = 1;
	if (s->workqueue)
		max3100_dowork(s);

	return 0;
}

#else
#define max3100_suspend NULL
#define max3100_resume  NULL
#endif

static struct spi_driver max3100_driver = {
	.driver = {
		.name		= "max3100",
		.owner		= THIS_MODULE,
	},

	.probe		= max3100_probe,
	.remove		= max3100_remove,
	.suspend	= max3100_suspend,
	.resume		= max3100_resume,
};

module_spi_driver(max3100_driver);

MODULE_DESCRIPTION("MAX3100 driver");
MODULE_AUTHOR("Christian Pellegrin <chripell@evolware.org>");
MODULE_LICENSE("GPL");
MODULE_ALIAS("spi:max3100");