aboutsummaryrefslogtreecommitdiff
path: root/drivers/tty/serial/mxs-auart.c
blob: 3a667eed63d6086c017c8abcc83a597850ec4966 (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
/*
 * Freescale STMP37XX/STMP378X Application UART driver
 *
 * Author: dmitry pervushin <dimka@embeddedalley.com>
 *
 * Copyright 2008-2010 Freescale Semiconductor, Inc.
 * Copyright 2008 Embedded Alley Solutions, Inc All Rights Reserved.
 *
 * The code contained herein is licensed under the GNU General Public
 * License. You may obtain a copy of the GNU General Public License
 * Version 2 or later at the following locations:
 *
 * http://www.opensource.org/licenses/gpl-license.html
 * http://www.gnu.org/copyleft/gpl.html
 */

#include <linux/kernel.h>
#include <linux/errno.h>
#include <linux/init.h>
#include <linux/console.h>
#include <linux/interrupt.h>
#include <linux/module.h>
#include <linux/slab.h>
#include <linux/wait.h>
#include <linux/tty.h>
#include <linux/tty_driver.h>
#include <linux/tty_flip.h>
#include <linux/serial.h>
#include <linux/serial_core.h>
#include <linux/platform_device.h>
#include <linux/device.h>
#include <linux/clk.h>
#include <linux/delay.h>
#include <linux/io.h>
#include <linux/pinctrl/consumer.h>
#include <linux/of_device.h>

#include <asm/cacheflush.h>

#define MXS_AUART_PORTS 5

#define AUART_CTRL0			0x00000000
#define AUART_CTRL0_SET			0x00000004
#define AUART_CTRL0_CLR			0x00000008
#define AUART_CTRL0_TOG			0x0000000c
#define AUART_CTRL1			0x00000010
#define AUART_CTRL1_SET			0x00000014
#define AUART_CTRL1_CLR			0x00000018
#define AUART_CTRL1_TOG			0x0000001c
#define AUART_CTRL2			0x00000020
#define AUART_CTRL2_SET			0x00000024
#define AUART_CTRL2_CLR			0x00000028
#define AUART_CTRL2_TOG			0x0000002c
#define AUART_LINECTRL			0x00000030
#define AUART_LINECTRL_SET		0x00000034
#define AUART_LINECTRL_CLR		0x00000038
#define AUART_LINECTRL_TOG		0x0000003c
#define AUART_LINECTRL2			0x00000040
#define AUART_LINECTRL2_SET		0x00000044
#define AUART_LINECTRL2_CLR		0x00000048
#define AUART_LINECTRL2_TOG		0x0000004c
#define AUART_INTR			0x00000050
#define AUART_INTR_SET			0x00000054
#define AUART_INTR_CLR			0x00000058
#define AUART_INTR_TOG			0x0000005c
#define AUART_DATA			0x00000060
#define AUART_STAT			0x00000070
#define AUART_DEBUG			0x00000080
#define AUART_VERSION			0x00000090
#define AUART_AUTOBAUD			0x000000a0

#define AUART_CTRL0_SFTRST			(1 << 31)
#define AUART_CTRL0_CLKGATE			(1 << 30)

#define AUART_CTRL2_CTSEN			(1 << 15)
#define AUART_CTRL2_RTSEN			(1 << 14)
#define AUART_CTRL2_RTS				(1 << 11)
#define AUART_CTRL2_RXE				(1 << 9)
#define AUART_CTRL2_TXE				(1 << 8)
#define AUART_CTRL2_UARTEN			(1 << 0)

#define AUART_LINECTRL_BAUD_DIVINT_SHIFT	16
#define AUART_LINECTRL_BAUD_DIVINT_MASK		0xffff0000
#define AUART_LINECTRL_BAUD_DIVINT(v)		(((v) & 0xffff) << 16)
#define AUART_LINECTRL_BAUD_DIVFRAC_SHIFT	8
#define AUART_LINECTRL_BAUD_DIVFRAC_MASK	0x00003f00
#define AUART_LINECTRL_BAUD_DIVFRAC(v)		(((v) & 0x3f) << 8)
#define AUART_LINECTRL_WLEN_MASK		0x00000060
#define AUART_LINECTRL_WLEN(v)			(((v) & 0x3) << 5)
#define AUART_LINECTRL_FEN			(1 << 4)
#define AUART_LINECTRL_STP2			(1 << 3)
#define AUART_LINECTRL_EPS			(1 << 2)
#define AUART_LINECTRL_PEN			(1 << 1)
#define AUART_LINECTRL_BRK			(1 << 0)

#define AUART_INTR_RTIEN			(1 << 22)
#define AUART_INTR_TXIEN			(1 << 21)
#define AUART_INTR_RXIEN			(1 << 20)
#define AUART_INTR_CTSMIEN			(1 << 17)
#define AUART_INTR_RTIS				(1 << 6)
#define AUART_INTR_TXIS				(1 << 5)
#define AUART_INTR_RXIS				(1 << 4)
#define AUART_INTR_CTSMIS			(1 << 1)

#define AUART_STAT_BUSY				(1 << 29)
#define AUART_STAT_CTS				(1 << 28)
#define AUART_STAT_TXFE				(1 << 27)
#define AUART_STAT_TXFF				(1 << 25)
#define AUART_STAT_RXFE				(1 << 24)
#define AUART_STAT_OERR				(1 << 19)
#define AUART_STAT_BERR				(1 << 18)
#define AUART_STAT_PERR				(1 << 17)
#define AUART_STAT_FERR				(1 << 16)

static struct uart_driver auart_driver;

struct mxs_auart_port {
	struct uart_port port;

	unsigned int flags;
	unsigned int ctrl;

	unsigned int irq;

	struct clk *clk;
	struct device *dev;
};

static void mxs_auart_stop_tx(struct uart_port *u);

#define to_auart_port(u) container_of(u, struct mxs_auart_port, port)

static inline void mxs_auart_tx_chars(struct mxs_auart_port *s)
{
	struct circ_buf *xmit = &s->port.state->xmit;

	while (!(readl(s->port.membase + AUART_STAT) &
		 AUART_STAT_TXFF)) {
		if (s->port.x_char) {
			s->port.icount.tx++;
			writel(s->port.x_char,
				     s->port.membase + AUART_DATA);
			s->port.x_char = 0;
			continue;
		}
		if (!uart_circ_empty(xmit) && !uart_tx_stopped(&s->port)) {
			s->port.icount.tx++;
			writel(xmit->buf[xmit->tail],
				     s->port.membase + AUART_DATA);
			xmit->tail = (xmit->tail + 1) & (UART_XMIT_SIZE - 1);
		} else
			break;
	}
	if (uart_circ_chars_pending(xmit) < WAKEUP_CHARS)
		uart_write_wakeup(&s->port);

	if (uart_circ_empty(&(s->port.state->xmit)))
		writel(AUART_INTR_TXIEN,
			     s->port.membase + AUART_INTR_CLR);
	else
		writel(AUART_INTR_TXIEN,
			     s->port.membase + AUART_INTR_SET);

	if (uart_tx_stopped(&s->port))
		mxs_auart_stop_tx(&s->port);
}

static void mxs_auart_rx_char(struct mxs_auart_port *s)
{
	int flag;
	u32 stat;
	u8 c;

	c = readl(s->port.membase + AUART_DATA);
	stat = readl(s->port.membase + AUART_STAT);

	flag = TTY_NORMAL;
	s->port.icount.rx++;

	if (stat & AUART_STAT_BERR) {
		s->port.icount.brk++;
		if (uart_handle_break(&s->port))
			goto out;
	} else if (stat & AUART_STAT_PERR) {
		s->port.icount.parity++;
	} else if (stat & AUART_STAT_FERR) {
		s->port.icount.frame++;
	}

	/*
	 * Mask off conditions which should be ingored.
	 */
	stat &= s->port.read_status_mask;

	if (stat & AUART_STAT_BERR) {
		flag = TTY_BREAK;
	} else if (stat & AUART_STAT_PERR)
		flag = TTY_PARITY;
	else if (stat & AUART_STAT_FERR)
		flag = TTY_FRAME;

	if (stat & AUART_STAT_OERR)
		s->port.icount.overrun++;

	if (uart_handle_sysrq_char(&s->port, c))
		goto out;

	uart_insert_char(&s->port, stat, AUART_STAT_OERR, c, flag);
out:
	writel(stat, s->port.membase + AUART_STAT);
}

static void mxs_auart_rx_chars(struct mxs_auart_port *s)
{
	struct tty_struct *tty = s->port.state->port.tty;
	u32 stat = 0;

	for (;;) {
		stat = readl(s->port.membase + AUART_STAT);
		if (stat & AUART_STAT_RXFE)
			break;
		mxs_auart_rx_char(s);
	}

	writel(stat, s->port.membase + AUART_STAT);
	tty_flip_buffer_push(tty);
}

static int mxs_auart_request_port(struct uart_port *u)
{
	return 0;
}

static int mxs_auart_verify_port(struct uart_port *u,
				    struct serial_struct *ser)
{
	if (u->type != PORT_UNKNOWN && u->type != PORT_IMX)
		return -EINVAL;
	return 0;
}

static void mxs_auart_config_port(struct uart_port *u, int flags)
{
}

static const char *mxs_auart_type(struct uart_port *u)
{
	struct mxs_auart_port *s = to_auart_port(u);

	return dev_name(s->dev);
}

static void mxs_auart_release_port(struct uart_port *u)
{
}

static void mxs_auart_set_mctrl(struct uart_port *u, unsigned mctrl)
{
	struct mxs_auart_port *s = to_auart_port(u);

	u32 ctrl = readl(u->membase + AUART_CTRL2);

	ctrl &= ~AUART_CTRL2_RTSEN;
	if (mctrl & TIOCM_RTS) {
		if (u->state->port.flags & ASYNC_CTS_FLOW)
			ctrl |= AUART_CTRL2_RTSEN;
	}

	s->ctrl = mctrl;
	writel(ctrl, u->membase + AUART_CTRL2);
}

static u32 mxs_auart_get_mctrl(struct uart_port *u)
{
	struct mxs_auart_port *s = to_auart_port(u);
	u32 stat = readl(u->membase + AUART_STAT);
	int ctrl2 = readl(u->membase + AUART_CTRL2);
	u32 mctrl = s->ctrl;

	mctrl &= ~TIOCM_CTS;
	if (stat & AUART_STAT_CTS)
		mctrl |= TIOCM_CTS;

	if (ctrl2 & AUART_CTRL2_RTS)
		mctrl |= TIOCM_RTS;

	return mctrl;
}

static void mxs_auart_settermios(struct uart_port *u,
				 struct ktermios *termios,
				 struct ktermios *old)
{
	u32 bm, ctrl, ctrl2, div;
	unsigned int cflag, baud;

	cflag = termios->c_cflag;

	ctrl = AUART_LINECTRL_FEN;
	ctrl2 = readl(u->membase + AUART_CTRL2);

	/* byte size */
	switch (cflag & CSIZE) {
	case CS5:
		bm = 0;
		break;
	case CS6:
		bm = 1;
		break;
	case CS7:
		bm = 2;
		break;
	case CS8:
		bm = 3;
		break;
	default:
		return;
	}

	ctrl |= AUART_LINECTRL_WLEN(bm);

	/* parity */
	if (cflag & PARENB) {
		ctrl |= AUART_LINECTRL_PEN;
		if ((cflag & PARODD) == 0)
			ctrl |= AUART_LINECTRL_EPS;
	}

	u->read_status_mask = 0;

	if (termios->c_iflag & INPCK)
		u->read_status_mask |= AUART_STAT_PERR;
	if (termios->c_iflag & (BRKINT | PARMRK))
		u->read_status_mask |= AUART_STAT_BERR;

	/*
	 * Characters to ignore
	 */
	u->ignore_status_mask = 0;
	if (termios->c_iflag & IGNPAR)
		u->ignore_status_mask |= AUART_STAT_PERR;
	if (termios->c_iflag & IGNBRK) {
		u->ignore_status_mask |= AUART_STAT_BERR;
		/*
		 * If we're ignoring parity and break indicators,
		 * ignore overruns too (for real raw support).
		 */
		if (termios->c_iflag & IGNPAR)
			u->ignore_status_mask |= AUART_STAT_OERR;
	}

	/*
	 * ignore all characters if CREAD is not set
	 */
	if (cflag & CREAD)
		ctrl2 |= AUART_CTRL2_RXE;
	else
		ctrl2 &= ~AUART_CTRL2_RXE;

	/* figure out the stop bits requested */
	if (cflag & CSTOPB)
		ctrl |= AUART_LINECTRL_STP2;

	/* figure out the hardware flow control settings */
	if (cflag & CRTSCTS)
		ctrl2 |= AUART_CTRL2_CTSEN | AUART_CTRL2_RTSEN;
	else
		ctrl2 &= ~(AUART_CTRL2_CTSEN | AUART_CTRL2_RTSEN);

	/* set baud rate */
	baud = uart_get_baud_rate(u, termios, old, 0, u->uartclk);
	div = u->uartclk * 32 / baud;
	ctrl |= AUART_LINECTRL_BAUD_DIVFRAC(div & 0x3F);
	ctrl |= AUART_LINECTRL_BAUD_DIVINT(div >> 6);

	writel(ctrl, u->membase + AUART_LINECTRL);
	writel(ctrl2, u->membase + AUART_CTRL2);

	uart_update_timeout(u, termios->c_cflag, baud);
}

static irqreturn_t mxs_auart_irq_handle(int irq, void *context)
{
	u32 istatus, istat;
	struct mxs_auart_port *s = context;
	u32 stat = readl(s->port.membase + AUART_STAT);

	istatus = istat = readl(s->port.membase + AUART_INTR);

	if (istat & AUART_INTR_CTSMIS) {
		uart_handle_cts_change(&s->port, stat & AUART_STAT_CTS);
		writel(AUART_INTR_CTSMIS,
				s->port.membase + AUART_INTR_CLR);
		istat &= ~AUART_INTR_CTSMIS;
	}

	if (istat & (AUART_INTR_RTIS | AUART_INTR_RXIS)) {
		mxs_auart_rx_chars(s);
		istat &= ~(AUART_INTR_RTIS | AUART_INTR_RXIS);
	}

	if (istat & AUART_INTR_TXIS) {
		mxs_auart_tx_chars(s);
		istat &= ~AUART_INTR_TXIS;
	}

	writel(istatus & (AUART_INTR_RTIS
		| AUART_INTR_TXIS
		| AUART_INTR_RXIS
		| AUART_INTR_CTSMIS),
			s->port.membase + AUART_INTR_CLR);

	return IRQ_HANDLED;
}

static void mxs_auart_reset(struct uart_port *u)
{
	int i;
	unsigned int reg;

	writel(AUART_CTRL0_SFTRST, u->membase + AUART_CTRL0_CLR);

	for (i = 0; i < 10000; i++) {
		reg = readl(u->membase + AUART_CTRL0);
		if (!(reg & AUART_CTRL0_SFTRST))
			break;
		udelay(3);
	}
	writel(AUART_CTRL0_CLKGATE, u->membase + AUART_CTRL0_CLR);
}

static int mxs_auart_startup(struct uart_port *u)
{
	struct mxs_auart_port *s = to_auart_port(u);

	clk_prepare_enable(s->clk);

	writel(AUART_CTRL0_CLKGATE, u->membase + AUART_CTRL0_CLR);

	writel(AUART_CTRL2_UARTEN, u->membase + AUART_CTRL2_SET);

	writel(AUART_INTR_RXIEN | AUART_INTR_RTIEN | AUART_INTR_CTSMIEN,
			u->membase + AUART_INTR);

	/*
	 * Enable fifo so all four bytes of a DMA word are written to
	 * output (otherwise, only the LSB is written, ie. 1 in 4 bytes)
	 */
	writel(AUART_LINECTRL_FEN, u->membase + AUART_LINECTRL_SET);

	return 0;
}

static void mxs_auart_shutdown(struct uart_port *u)
{
	struct mxs_auart_port *s = to_auart_port(u);

	writel(AUART_CTRL2_UARTEN, u->membase + AUART_CTRL2_CLR);

	writel(AUART_CTRL0_CLKGATE, u->membase + AUART_CTRL0_SET);

	writel(AUART_INTR_RXIEN | AUART_INTR_RTIEN | AUART_INTR_CTSMIEN,
			u->membase + AUART_INTR_CLR);

	clk_disable_unprepare(s->clk);
}

static unsigned int mxs_auart_tx_empty(struct uart_port *u)
{
	if (readl(u->membase + AUART_STAT) & AUART_STAT_TXFE)
		return TIOCSER_TEMT;
	else
		return 0;
}

static void mxs_auart_start_tx(struct uart_port *u)
{
	struct mxs_auart_port *s = to_auart_port(u);

	/* enable transmitter */
	writel(AUART_CTRL2_TXE, u->membase + AUART_CTRL2_SET);

	mxs_auart_tx_chars(s);
}

static void mxs_auart_stop_tx(struct uart_port *u)
{
	writel(AUART_CTRL2_TXE, u->membase + AUART_CTRL2_CLR);
}

static void mxs_auart_stop_rx(struct uart_port *u)
{
	writel(AUART_CTRL2_RXE, u->membase + AUART_CTRL2_CLR);
}

static void mxs_auart_break_ctl(struct uart_port *u, int ctl)
{
	if (ctl)
		writel(AUART_LINECTRL_BRK,
			     u->membase + AUART_LINECTRL_SET);
	else
		writel(AUART_LINECTRL_BRK,
			     u->membase + AUART_LINECTRL_CLR);
}

static void mxs_auart_enable_ms(struct uart_port *port)
{
	/* just empty */
}

static struct uart_ops mxs_auart_ops = {
	.tx_empty       = mxs_auart_tx_empty,
	.start_tx       = mxs_auart_start_tx,
	.stop_tx	= mxs_auart_stop_tx,
	.stop_rx	= mxs_auart_stop_rx,
	.enable_ms      = mxs_auart_enable_ms,
	.break_ctl      = mxs_auart_break_ctl,
	.set_mctrl	= mxs_auart_set_mctrl,
	.get_mctrl      = mxs_auart_get_mctrl,
	.startup	= mxs_auart_startup,
	.shutdown       = mxs_auart_shutdown,
	.set_termios    = mxs_auart_settermios,
	.type	   	= mxs_auart_type,
	.release_port   = mxs_auart_release_port,
	.request_port   = mxs_auart_request_port,
	.config_port    = mxs_auart_config_port,
	.verify_port    = mxs_auart_verify_port,
};

static struct mxs_auart_port *auart_port[MXS_AUART_PORTS];

#ifdef CONFIG_SERIAL_MXS_AUART_CONSOLE
static void mxs_auart_console_putchar(struct uart_port *port, int ch)
{
	unsigned int to = 1000;

	while (readl(port->membase + AUART_STAT) & AUART_STAT_TXFF) {
		if (!to--)
			break;
		udelay(1);
	}

	writel(ch, port->membase + AUART_DATA);
}

static void
auart_console_write(struct console *co, const char *str, unsigned int count)
{
	struct mxs_auart_port *s;
	struct uart_port *port;
	unsigned int old_ctrl0, old_ctrl2;
	unsigned int to = 1000;

	if (co->index >	MXS_AUART_PORTS || co->index < 0)
		return;

	s = auart_port[co->index];
	port = &s->port;

	clk_enable(s->clk);

	/* First save the CR then disable the interrupts */
	old_ctrl2 = readl(port->membase + AUART_CTRL2);
	old_ctrl0 = readl(port->membase + AUART_CTRL0);

	writel(AUART_CTRL0_CLKGATE,
		     port->membase + AUART_CTRL0_CLR);
	writel(AUART_CTRL2_UARTEN | AUART_CTRL2_TXE,
		     port->membase + AUART_CTRL2_SET);

	uart_console_write(port, str, count, mxs_auart_console_putchar);

	/*
	 * Finally, wait for transmitter to become empty
	 * and restore the TCR
	 */
	while (readl(port->membase + AUART_STAT) & AUART_STAT_BUSY) {
		if (!to--)
			break;
		udelay(1);
	}

	writel(old_ctrl0, port->membase + AUART_CTRL0);
	writel(old_ctrl2, port->membase + AUART_CTRL2);

	clk_disable(s->clk);
}

static void __init
auart_console_get_options(struct uart_port *port, int *baud,
			  int *parity, int *bits)
{
	unsigned int lcr_h, quot;

	if (!(readl(port->membase + AUART_CTRL2) & AUART_CTRL2_UARTEN))
		return;

	lcr_h = readl(port->membase + AUART_LINECTRL);

	*parity = 'n';
	if (lcr_h & AUART_LINECTRL_PEN) {
		if (lcr_h & AUART_LINECTRL_EPS)
			*parity = 'e';
		else
			*parity = 'o';
	}

	if ((lcr_h & AUART_LINECTRL_WLEN_MASK) == AUART_LINECTRL_WLEN(2))
		*bits = 7;
	else
		*bits = 8;

	quot = ((readl(port->membase + AUART_LINECTRL)
			& AUART_LINECTRL_BAUD_DIVINT_MASK))
			    >> (AUART_LINECTRL_BAUD_DIVINT_SHIFT - 6);
	quot |= ((readl(port->membase + AUART_LINECTRL)
			& AUART_LINECTRL_BAUD_DIVFRAC_MASK))
				>> AUART_LINECTRL_BAUD_DIVFRAC_SHIFT;
	if (quot == 0)
		quot = 1;

	*baud = (port->uartclk << 2) / quot;
}

static int __init
auart_console_setup(struct console *co, char *options)
{
	struct mxs_auart_port *s;
	int baud = 9600;
	int bits = 8;
	int parity = 'n';
	int flow = 'n';
	int ret;

	/*
	 * Check whether an invalid uart number has been specified, and
	 * if so, search for the first available port that does have
	 * console support.
	 */
	if (co->index == -1 || co->index >= ARRAY_SIZE(auart_port))
		co->index = 0;
	s = auart_port[co->index];
	if (!s)
		return -ENODEV;

	clk_prepare_enable(s->clk);

	if (options)
		uart_parse_options(options, &baud, &parity, &bits, &flow);
	else
		auart_console_get_options(&s->port, &baud, &parity, &bits);

	ret = uart_set_options(&s->port, co, baud, parity, bits, flow);

	clk_disable_unprepare(s->clk);

	return ret;
}

static struct console auart_console = {
	.name		= "ttyAPP",
	.write		= auart_console_write,
	.device		= uart_console_device,
	.setup		= auart_console_setup,
	.flags		= CON_PRINTBUFFER,
	.index		= -1,
	.data		= &auart_driver,
};
#endif

static struct uart_driver auart_driver = {
	.owner		= THIS_MODULE,
	.driver_name	= "ttyAPP",
	.dev_name	= "ttyAPP",
	.major		= 0,
	.minor		= 0,
	.nr		= MXS_AUART_PORTS,
#ifdef CONFIG_SERIAL_MXS_AUART_CONSOLE
	.cons =		&auart_console,
#endif
};

/*
 * This function returns 1 if pdev isn't a device instatiated by dt, 0 if it
 * could successfully get all information from dt or a negative errno.
 */
static int serial_mxs_probe_dt(struct mxs_auart_port *s,
		struct platform_device *pdev)
{
	struct device_node *np = pdev->dev.of_node;
	int ret;

	if (!np)
		/* no device tree device */
		return 1;

	ret = of_alias_get_id(np, "serial");
	if (ret < 0) {
		dev_err(&pdev->dev, "failed to get alias id: %d\n", ret);
		return ret;
	}
	s->port.line = ret;

	return 0;
}

static int __devinit mxs_auart_probe(struct platform_device *pdev)
{
	struct mxs_auart_port *s;
	u32 version;
	int ret = 0;
	struct resource *r;
	struct pinctrl *pinctrl;

	s = kzalloc(sizeof(struct mxs_auart_port), GFP_KERNEL);
	if (!s) {
		ret = -ENOMEM;
		goto out;
	}

	ret = serial_mxs_probe_dt(s, pdev);
	if (ret > 0)
		s->port.line = pdev->id < 0 ? 0 : pdev->id;
	else if (ret < 0)
		goto out_free;

	pinctrl = devm_pinctrl_get_select_default(&pdev->dev);
	if (IS_ERR(pinctrl)) {
		ret = PTR_ERR(pinctrl);
		goto out_free;
	}

	s->clk = clk_get(&pdev->dev, NULL);
	if (IS_ERR(s->clk)) {
		ret = PTR_ERR(s->clk);
		goto out_free;
	}

	r = platform_get_resource(pdev, IORESOURCE_MEM, 0);
	if (!r) {
		ret = -ENXIO;
		goto out_free_clk;
	}

	s->port.mapbase = r->start;
	s->port.membase = ioremap(r->start, resource_size(r));
	s->port.ops = &mxs_auart_ops;
	s->port.iotype = UPIO_MEM;
	s->port.fifosize = 16;
	s->port.uartclk = clk_get_rate(s->clk);
	s->port.type = PORT_IMX;
	s->port.dev = s->dev = get_device(&pdev->dev);

	s->flags = 0;
	s->ctrl = 0;

	s->irq = platform_get_irq(pdev, 0);
	s->port.irq = s->irq;
	ret = request_irq(s->irq, mxs_auart_irq_handle, 0, dev_name(&pdev->dev), s);
	if (ret)
		goto out_free_clk;

	platform_set_drvdata(pdev, s);

	auart_port[s->port.line] = s;

	mxs_auart_reset(&s->port);

	ret = uart_add_one_port(&auart_driver, &s->port);
	if (ret)
		goto out_free_irq;

	version = readl(s->port.membase + AUART_VERSION);
	dev_info(&pdev->dev, "Found APPUART %d.%d.%d\n",
	       (version >> 24) & 0xff,
	       (version >> 16) & 0xff, version & 0xffff);

	return 0;

out_free_irq:
	auart_port[pdev->id] = NULL;
	free_irq(s->irq, s);
out_free_clk:
	clk_put(s->clk);
out_free:
	kfree(s);
out:
	return ret;
}

static int __devexit mxs_auart_remove(struct platform_device *pdev)
{
	struct mxs_auart_port *s = platform_get_drvdata(pdev);

	uart_remove_one_port(&auart_driver, &s->port);

	auart_port[pdev->id] = NULL;

	clk_put(s->clk);
	free_irq(s->irq, s);
	kfree(s);

	return 0;
}

static struct of_device_id mxs_auart_dt_ids[] = {
	{ .compatible = "fsl,imx23-auart", },
	{ /* sentinel */ }
};
MODULE_DEVICE_TABLE(of, mxs_auart_dt_ids);

static struct platform_driver mxs_auart_driver = {
	.probe = mxs_auart_probe,
	.remove = __devexit_p(mxs_auart_remove),
	.driver = {
		.name = "mxs-auart",
		.owner = THIS_MODULE,
		.of_match_table = mxs_auart_dt_ids,
	},
};

static int __init mxs_auart_init(void)
{
	int r;

	r = uart_register_driver(&auart_driver);
	if (r)
		goto out;

	r = platform_driver_register(&mxs_auart_driver);
	if (r)
		goto out_err;

	return 0;
out_err:
	uart_unregister_driver(&auart_driver);
out:
	return r;
}

static void __exit mxs_auart_exit(void)
{
	platform_driver_unregister(&mxs_auart_driver);
	uart_unregister_driver(&auart_driver);
}

module_init(mxs_auart_init);
module_exit(mxs_auart_exit);
MODULE_LICENSE("GPL");
MODULE_DESCRIPTION("Freescale MXS application uart driver");
MODULE_ALIAS("platform:mxs-auart");