summaryrefslogtreecommitdiffstats
path: root/drivers/i2c/busses/i2c-omap.c
blob: c73475dd0fba00c2dd5953b3b37ebf5837ad7f37 (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
921
922
923
924
925
926
927
928
929
930
931
932
933
934
935
936
937
938
939
940
941
942
943
944
945
946
947
948
949
950
951
952
953
954
955
956
957
958
/*
 * TI OMAP I2C master mode driver
 *
 * Copyright (C) 2003 MontaVista Software, Inc.
 * Copyright (C) 2005 Nokia Corporation
 * Copyright (C) 2004 - 2007 Texas Instruments.
 *
 * Originally written by MontaVista Software, Inc.
 * Additional contributions by:
 *	Tony Lindgren <tony@atomide.com>
 *	Imre Deak <imre.deak@nokia.com>
 *	Juha Yrjölä <juha.yrjola@solidboot.com>
 *	Syed Khasim <x0khasim@ti.com>
 *	Nishant Menon <nm@ti.com>
 *
 * 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.
 *
 * This program is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
 * GNU General Public License for more details.
 *
 * You should have received a copy of the GNU General Public License
 * along with this program; if not, write to the Free Software
 * Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
 */

#include <linux/module.h>
#include <linux/delay.h>
#include <linux/i2c.h>
#include <linux/err.h>
#include <linux/interrupt.h>
#include <linux/completion.h>
#include <linux/platform_device.h>
#include <linux/clk.h>
#include <linux/io.h>

/* I2C controller revisions */
#define OMAP_I2C_REV_2			0x20

/* I2C controller revisions present on specific hardware */
#define OMAP_I2C_REV_ON_2430		0x36
#define OMAP_I2C_REV_ON_3430		0x3C

/* timeout waiting for the controller to respond */
#define OMAP_I2C_TIMEOUT (msecs_to_jiffies(1000))

#define OMAP_I2C_REV_REG		0x00
#define OMAP_I2C_IE_REG			0x04
#define OMAP_I2C_STAT_REG		0x08
#define OMAP_I2C_IV_REG			0x0c
/* For OMAP3 I2C_IV has changed to I2C_WE (wakeup enable) */
#define OMAP_I2C_WE_REG			0x0c
#define OMAP_I2C_SYSS_REG		0x10
#define OMAP_I2C_BUF_REG		0x14
#define OMAP_I2C_CNT_REG		0x18
#define OMAP_I2C_DATA_REG		0x1c
#define OMAP_I2C_SYSC_REG		0x20
#define OMAP_I2C_CON_REG		0x24
#define OMAP_I2C_OA_REG			0x28
#define OMAP_I2C_SA_REG			0x2c
#define OMAP_I2C_PSC_REG		0x30
#define OMAP_I2C_SCLL_REG		0x34
#define OMAP_I2C_SCLH_REG		0x38
#define OMAP_I2C_SYSTEST_REG		0x3c
#define OMAP_I2C_BUFSTAT_REG		0x40

/* I2C Interrupt Enable Register (OMAP_I2C_IE): */
#define OMAP_I2C_IE_XDR		(1 << 14)	/* TX Buffer drain int enable */
#define OMAP_I2C_IE_RDR		(1 << 13)	/* RX Buffer drain int enable */
#define OMAP_I2C_IE_XRDY	(1 << 4)	/* TX data ready int enable */
#define OMAP_I2C_IE_RRDY	(1 << 3)	/* RX data ready int enable */
#define OMAP_I2C_IE_ARDY	(1 << 2)	/* Access ready int enable */
#define OMAP_I2C_IE_NACK	(1 << 1)	/* No ack interrupt enable */
#define OMAP_I2C_IE_AL		(1 << 0)	/* Arbitration lost int ena */

/* I2C Status Register (OMAP_I2C_STAT): */
#define OMAP_I2C_STAT_XDR	(1 << 14)	/* TX Buffer draining */
#define OMAP_I2C_STAT_RDR	(1 << 13)	/* RX Buffer draining */
#define OMAP_I2C_STAT_BB	(1 << 12)	/* Bus busy */
#define OMAP_I2C_STAT_ROVR	(1 << 11)	/* Receive overrun */
#define OMAP_I2C_STAT_XUDF	(1 << 10)	/* Transmit underflow */
#define OMAP_I2C_STAT_AAS	(1 << 9)	/* Address as slave */
#define OMAP_I2C_STAT_AD0	(1 << 8)	/* Address zero */
#define OMAP_I2C_STAT_XRDY	(1 << 4)	/* Transmit data ready */
#define OMAP_I2C_STAT_RRDY	(1 << 3)	/* Receive data ready */
#define OMAP_I2C_STAT_ARDY	(1 << 2)	/* Register access ready */
#define OMAP_I2C_STAT_NACK	(1 << 1)	/* No ack interrupt enable */
#define OMAP_I2C_STAT_AL	(1 << 0)	/* Arbitration lost int ena */

/* I2C WE wakeup enable register */
#define OMAP_I2C_WE_XDR_WE	(1 << 14)	/* TX drain wakup */
#define OMAP_I2C_WE_RDR_WE	(1 << 13)	/* RX drain wakeup */
#define OMAP_I2C_WE_AAS_WE	(1 << 9)	/* Address as slave wakeup*/
#define OMAP_I2C_WE_BF_WE	(1 << 8)	/* Bus free wakeup */
#define OMAP_I2C_WE_STC_WE	(1 << 6)	/* Start condition wakeup */
#define OMAP_I2C_WE_GC_WE	(1 << 5)	/* General call wakeup */
#define OMAP_I2C_WE_DRDY_WE	(1 << 3)	/* TX/RX data ready wakeup */
#define OMAP_I2C_WE_ARDY_WE	(1 << 2)	/* Reg access ready wakeup */
#define OMAP_I2C_WE_NACK_WE	(1 << 1)	/* No acknowledgment wakeup */
#define OMAP_I2C_WE_AL_WE	(1 << 0)	/* Arbitration lost wakeup */

#define OMAP_I2C_WE_ALL		(OMAP_I2C_WE_XDR_WE | OMAP_I2C_WE_RDR_WE | \
				OMAP_I2C_WE_AAS_WE | OMAP_I2C_WE_BF_WE | \
				OMAP_I2C_WE_STC_WE | OMAP_I2C_WE_GC_WE | \
				OMAP_I2C_WE_DRDY_WE | OMAP_I2C_WE_ARDY_WE | \
				OMAP_I2C_WE_NACK_WE | OMAP_I2C_WE_AL_WE)

/* I2C Buffer Configuration Register (OMAP_I2C_BUF): */
#define OMAP_I2C_BUF_RDMA_EN	(1 << 15)	/* RX DMA channel enable */
#define OMAP_I2C_BUF_RXFIF_CLR	(1 << 14)	/* RX FIFO Clear */
#define OMAP_I2C_BUF_XDMA_EN	(1 << 7)	/* TX DMA channel enable */
#define OMAP_I2C_BUF_TXFIF_CLR	(1 << 6)	/* TX FIFO Clear */

/* I2C Configuration Register (OMAP_I2C_CON): */
#define OMAP_I2C_CON_EN		(1 << 15)	/* I2C module enable */
#define OMAP_I2C_CON_BE		(1 << 14)	/* Big endian mode */
#define OMAP_I2C_CON_OPMODE_HS	(1 << 12)	/* High Speed support */
#define OMAP_I2C_CON_STB	(1 << 11)	/* Start byte mode (master) */
#define OMAP_I2C_CON_MST	(1 << 10)	/* Master/slave mode */
#define OMAP_I2C_CON_TRX	(1 << 9)	/* TX/RX mode (master only) */
#define OMAP_I2C_CON_XA		(1 << 8)	/* Expand address */
#define OMAP_I2C_CON_RM		(1 << 2)	/* Repeat mode (master only) */
#define OMAP_I2C_CON_STP	(1 << 1)	/* Stop cond (master only) */
#define OMAP_I2C_CON_STT	(1 << 0)	/* Start condition (master) */

/* I2C SCL time value when Master */
#define OMAP_I2C_SCLL_HSSCLL	8
#define OMAP_I2C_SCLH_HSSCLH	8

/* I2C System Test Register (OMAP_I2C_SYSTEST): */
#ifdef DEBUG
#define OMAP_I2C_SYSTEST_ST_EN		(1 << 15)	/* System test enable */
#define OMAP_I2C_SYSTEST_FREE		(1 << 14)	/* Free running mode */
#define OMAP_I2C_SYSTEST_TMODE_MASK	(3 << 12)	/* Test mode select */
#define OMAP_I2C_SYSTEST_TMODE_SHIFT	(12)		/* Test mode select */
#define OMAP_I2C_SYSTEST_SCL_I		(1 << 3)	/* SCL line sense in */
#define OMAP_I2C_SYSTEST_SCL_O		(1 << 2)	/* SCL line drive out */
#define OMAP_I2C_SYSTEST_SDA_I		(1 << 1)	/* SDA line sense in */
#define OMAP_I2C_SYSTEST_SDA_O		(1 << 0)	/* SDA line drive out */
#endif

/* OCP_SYSSTATUS bit definitions */
#define SYSS_RESETDONE_MASK		(1 << 0)

/* OCP_SYSCONFIG bit definitions */
#define SYSC_CLOCKACTIVITY_MASK		(0x3 << 8)
#define SYSC_SIDLEMODE_MASK		(0x3 << 3)
#define SYSC_ENAWAKEUP_MASK		(1 << 2)
#define SYSC_SOFTRESET_MASK		(1 << 1)
#define SYSC_AUTOIDLE_MASK		(1 << 0)

#define SYSC_IDLEMODE_SMART		0x2
#define SYSC_CLOCKACTIVITY_FCLK		0x2


struct omap_i2c_dev {
	struct device		*dev;
	void __iomem		*base;		/* virtual */
	int			irq;
	struct clk		*iclk;		/* Interface clock */
	struct clk		*fclk;		/* Functional clock */
	struct completion	cmd_complete;
	struct resource		*ioarea;
	u32			speed;		/* Speed of bus in Khz */
	u16			cmd_err;
	u8			*buf;
	size_t			buf_len;
	struct i2c_adapter	adapter;
	u8			fifo_size;	/* use as flag and value
						 * fifo_size==0 implies no fifo
						 * if set, should be trsh+1
						 */
	u8			rev;
	unsigned		b_hw:1;		/* bad h/w fixes */
	unsigned		idle:1;
	u16			iestate;	/* Saved interrupt register */
};

static inline void omap_i2c_write_reg(struct omap_i2c_dev *i2c_dev,
				      int reg, u16 val)
{
	__raw_writew(val, i2c_dev->base + reg);
}

static inline u16 omap_i2c_read_reg(struct omap_i2c_dev *i2c_dev, int reg)
{
	return __raw_readw(i2c_dev->base + reg);
}

static int __init omap_i2c_get_clocks(struct omap_i2c_dev *dev)
{
	int ret;

	dev->iclk = clk_get(dev->dev, "ick");
	if (IS_ERR(dev->iclk)) {
		ret = PTR_ERR(dev->iclk);
		dev->iclk = NULL;
		return ret;
	}

	dev->fclk = clk_get(dev->dev, "fck");
	if (IS_ERR(dev->fclk)) {
		ret = PTR_ERR(dev->fclk);
		if (dev->iclk != NULL) {
			clk_put(dev->iclk);
			dev->iclk = NULL;
		}
		dev->fclk = NULL;
		return ret;
	}

	return 0;
}

static void omap_i2c_put_clocks(struct omap_i2c_dev *dev)
{
	clk_put(dev->fclk);
	dev->fclk = NULL;
	clk_put(dev->iclk);
	dev->iclk = NULL;
}

static void omap_i2c_unidle(struct omap_i2c_dev *dev)
{
	WARN_ON(!dev->idle);

	clk_enable(dev->iclk);
	clk_enable(dev->fclk);
	dev->idle = 0;
	if (dev->iestate)
		omap_i2c_write_reg(dev, OMAP_I2C_IE_REG, dev->iestate);
}

static void omap_i2c_idle(struct omap_i2c_dev *dev)
{
	u16 iv;

	WARN_ON(dev->idle);

	dev->iestate = omap_i2c_read_reg(dev, OMAP_I2C_IE_REG);
	omap_i2c_write_reg(dev, OMAP_I2C_IE_REG, 0);
	if (dev->rev < OMAP_I2C_REV_2) {
		iv = omap_i2c_read_reg(dev, OMAP_I2C_IV_REG); /* Read clears */
	} else {
		omap_i2c_write_reg(dev, OMAP_I2C_STAT_REG, dev->iestate);

		/* Flush posted write before the dev->idle store occurs */
		omap_i2c_read_reg(dev, OMAP_I2C_STAT_REG);
	}
	dev->idle = 1;
	clk_disable(dev->fclk);
	clk_disable(dev->iclk);
}

static int omap_i2c_init(struct omap_i2c_dev *dev)
{
	u16 psc = 0, scll = 0, sclh = 0;
	u16 fsscll = 0, fssclh = 0, hsscll = 0, hssclh = 0;
	unsigned long fclk_rate = 12000000;
	unsigned long timeout;
	unsigned long internal_clk = 0;

	if (dev->rev >= OMAP_I2C_REV_2) {
		omap_i2c_write_reg(dev, OMAP_I2C_SYSC_REG, SYSC_SOFTRESET_MASK);
		/* For some reason we need to set the EN bit before the
		 * reset done bit gets set. */
		timeout = jiffies + OMAP_I2C_TIMEOUT;
		omap_i2c_write_reg(dev, OMAP_I2C_CON_REG, OMAP_I2C_CON_EN);
		while (!(omap_i2c_read_reg(dev, OMAP_I2C_SYSS_REG) &
			 SYSS_RESETDONE_MASK)) {
			if (time_after(jiffies, timeout)) {
				dev_warn(dev->dev, "timeout waiting "
						"for controller reset\n");
				return -ETIMEDOUT;
			}
			msleep(1);
		}

		/* SYSC register is cleared by the reset; rewrite it */
		if (dev->rev == OMAP_I2C_REV_ON_2430) {

			omap_i2c_write_reg(dev, OMAP_I2C_SYSC_REG,
					   SYSC_AUTOIDLE_MASK);

		} else if (dev->rev >= OMAP_I2C_REV_ON_3430) {
			u32 v;

			v = SYSC_AUTOIDLE_MASK;
			v |= SYSC_ENAWAKEUP_MASK;
			v |= (SYSC_IDLEMODE_SMART <<
			      __ffs(SYSC_SIDLEMODE_MASK));
			v |= (SYSC_CLOCKACTIVITY_FCLK <<
			      __ffs(SYSC_CLOCKACTIVITY_MASK));

			omap_i2c_write_reg(dev, OMAP_I2C_SYSC_REG, v);
			/*
			 * Enabling all wakup sources to stop I2C freezing on
			 * WFI instruction.
			 * REVISIT: Some wkup sources might not be needed.
			 */
			omap_i2c_write_reg(dev, OMAP_I2C_WE_REG,
							OMAP_I2C_WE_ALL);

		}
	}
	omap_i2c_write_reg(dev, OMAP_I2C_CON_REG, 0);

	if (cpu_class_is_omap1()) {
		/*
		 * The I2C functional clock is the armxor_ck, so there's
		 * no need to get "armxor_ck" separately.  Now, if OMAP2420
		 * always returns 12MHz for the functional clock, we can
		 * do this bit unconditionally.
		 */
		fclk_rate = clk_get_rate(dev->fclk);

		/* TRM for 5912 says the I2C clock must be prescaled to be
		 * between 7 - 12 MHz. The XOR input clock is typically
		 * 12, 13 or 19.2 MHz. So we should have code that produces:
		 *
		 * XOR MHz	Divider		Prescaler
		 * 12		1		0
		 * 13		2		1
		 * 19.2		2		1
		 */
		if (fclk_rate > 12000000)
			psc = fclk_rate / 12000000;
	}

	if (cpu_is_omap2430() || cpu_is_omap34xx()) {

		/*
		 * HSI2C controller internal clk rate should be 19.2 Mhz for
		 * HS and for all modes on 2430. On 34xx we can use lower rate
		 * to get longer filter period for better noise suppression.
		 * The filter is iclk (fclk for HS) period.
		 */
		if (dev->speed > 400 || cpu_is_omap_2430())
			internal_clk = 19200;
		else if (dev->speed > 100)
			internal_clk = 9600;
		else
			internal_clk = 4000;
		fclk_rate = clk_get_rate(dev->fclk) / 1000;

		/* Compute prescaler divisor */
		psc = fclk_rate / internal_clk;
		psc = psc - 1;

		/* If configured for High Speed */
		if (dev->speed > 400) {
			unsigned long scl;

			/* For first phase of HS mode */
			scl = internal_clk / 400;
			fsscll = scl - (scl / 3) - 7;
			fssclh = (scl / 3) - 5;

			/* For second phase of HS mode */
			scl = fclk_rate / dev->speed;
			hsscll = scl - (scl / 3) - 7;
			hssclh = (scl / 3) - 5;
		} else if (dev->speed > 100) {
			unsigned long scl;

			/* Fast mode */
			scl = internal_clk / dev->speed;
			fsscll = scl - (scl / 3) - 7;
			fssclh = (scl / 3) - 5;
		} else {
			/* Standard mode */
			fsscll = internal_clk / (dev->speed * 2) - 7;
			fssclh = internal_clk / (dev->speed * 2) - 5;
		}
		scll = (hsscll << OMAP_I2C_SCLL_HSSCLL) | fsscll;
		sclh = (hssclh << OMAP_I2C_SCLH_HSSCLH) | fssclh;
	} else {
		/* Program desired operating rate */
		fclk_rate /= (psc + 1) * 1000;
		if (psc > 2)
			psc = 2;
		scll = fclk_rate / (dev->speed * 2) - 7 + psc;
		sclh = fclk_rate / (dev->speed * 2) - 7 + psc;
	}

	/* Setup clock prescaler to obtain approx 12MHz I2C module clock: */
	omap_i2c_write_reg(dev, OMAP_I2C_PSC_REG, psc);

	/* SCL low and high time values */
	omap_i2c_write_reg(dev, OMAP_I2C_SCLL_REG, scll);
	omap_i2c_write_reg(dev, OMAP_I2C_SCLH_REG, sclh);

	if (dev->fifo_size)
		/* Note: setup required fifo size - 1 */
		omap_i2c_write_reg(dev, OMAP_I2C_BUF_REG,
					(dev->fifo_size - 1) << 8 | /* RTRSH */
					OMAP_I2C_BUF_RXFIF_CLR |
					(dev->fifo_size - 1) | /* XTRSH */
					OMAP_I2C_BUF_TXFIF_CLR);

	/* Take the I2C module out of reset: */
	omap_i2c_write_reg(dev, OMAP_I2C_CON_REG, OMAP_I2C_CON_EN);

	/* Enable interrupts */
	omap_i2c_write_reg(dev, OMAP_I2C_IE_REG,
			(OMAP_I2C_IE_XRDY | OMAP_I2C_IE_RRDY |
			OMAP_I2C_IE_ARDY | OMAP_I2C_IE_NACK |
			OMAP_I2C_IE_AL)  | ((dev->fifo_size) ?
				(OMAP_I2C_IE_RDR | OMAP_I2C_IE_XDR) : 0));
	return 0;
}

/*
 * Waiting on Bus Busy
 */
static int omap_i2c_wait_for_bb(struct omap_i2c_dev *dev)
{
	unsigned long timeout;

	timeout = jiffies + OMAP_I2C_TIMEOUT;
	while (omap_i2c_read_reg(dev, OMAP_I2C_STAT_REG) & OMAP_I2C_STAT_BB) {
		if (time_after(jiffies, timeout)) {
			dev_warn(dev->dev, "timeout waiting for bus ready\n");
			return -ETIMEDOUT;
		}
		msleep(1);
	}

	return 0;
}

/*
 * Low level master read/write transaction.
 */
static int omap_i2c_xfer_msg(struct i2c_adapter *adap,
			     struct i2c_msg *msg, int stop)
{
	struct omap_i2c_dev *dev = i2c_get_adapdata(adap);
	int r;
	u16 w;

	dev_dbg(dev->dev, "addr: 0x%04x, len: %d, flags: 0x%x, stop: %d\n",
		msg->addr, msg->len, msg->flags, stop);

	if (msg->len == 0)
		return -EINVAL;

	omap_i2c_write_reg(dev, OMAP_I2C_SA_REG, msg->addr);

	/* REVISIT: Could the STB bit of I2C_CON be used with probing? */
	dev->buf = msg->buf;
	dev->buf_len = msg->len;

	omap_i2c_write_reg(dev, OMAP_I2C_CNT_REG, dev->buf_len);

	/* Clear the FIFO Buffers */
	w = omap_i2c_read_reg(dev, OMAP_I2C_BUF_REG);
	w |= OMAP_I2C_BUF_RXFIF_CLR | OMAP_I2C_BUF_TXFIF_CLR;
	omap_i2c_write_reg(dev, OMAP_I2C_BUF_REG, w);

	init_completion(&dev->cmd_complete);
	dev->cmd_err = 0;

	w = OMAP_I2C_CON_EN | OMAP_I2C_CON_MST | OMAP_I2C_CON_STT;

	/* High speed configuration */
	if (dev->speed > 400)
		w |= OMAP_I2C_CON_OPMODE_HS;

	if (msg->flags & I2C_M_TEN)
		w |= OMAP_I2C_CON_XA;
	if (!(msg->flags & I2C_M_RD))
		w |= OMAP_I2C_CON_TRX;

	if (!dev->b_hw && stop)
		w |= OMAP_I2C_CON_STP;

	omap_i2c_write_reg(dev, OMAP_I2C_CON_REG, w);

	/*
	 * Don't write stt and stp together on some hardware.
	 */
	if (dev->b_hw && stop) {
		unsigned long delay = jiffies + OMAP_I2C_TIMEOUT;
		u16 con = omap_i2c_read_reg(dev, OMAP_I2C_CON_REG);
		while (con & OMAP_I2C_CON_STT) {
			con = omap_i2c_read_reg(dev, OMAP_I2C_CON_REG);

			/* Let the user know if i2c is in a bad state */
			if (time_after(jiffies, delay)) {
				dev_err(dev->dev, "controller timed out "
				"waiting for start condition to finish\n");
				return -ETIMEDOUT;
			}
			cpu_relax();
		}

		w |= OMAP_I2C_CON_STP;
		w &= ~OMAP_I2C_CON_STT;
		omap_i2c_write_reg(dev, OMAP_I2C_CON_REG, w);
	}

	/*
	 * REVISIT: We should abort the transfer on signals, but the bus goes
	 * into arbitration and we're currently unable to recover from it.
	 */
	r = wait_for_completion_timeout(&dev->cmd_complete,
					OMAP_I2C_TIMEOUT);
	dev->buf_len = 0;
	if (r < 0)
		return r;
	if (r == 0) {
		dev_err(dev->dev, "controller timed out\n");
		omap_i2c_init(dev);
		return -ETIMEDOUT;
	}

	if (likely(!dev->cmd_err))
		return 0;

	/* We have an error */
	if (dev->cmd_err & (OMAP_I2C_STAT_AL | OMAP_I2C_STAT_ROVR |
			    OMAP_I2C_STAT_XUDF)) {
		omap_i2c_init(dev);
		return -EIO;
	}

	if (dev->cmd_err & OMAP_I2C_STAT_NACK) {
		if (msg->flags & I2C_M_IGNORE_NAK)
			return 0;
		if (stop) {
			w = omap_i2c_read_reg(dev, OMAP_I2C_CON_REG);
			w |= OMAP_I2C_CON_STP;
			omap_i2c_write_reg(dev, OMAP_I2C_CON_REG, w);
		}
		return -EREMOTEIO;
	}
	return -EIO;
}


/*
 * Prepare controller for a transaction and call omap_i2c_xfer_msg
 * to do the work during IRQ processing.
 */
static int
omap_i2c_xfer(struct i2c_adapter *adap, struct i2c_msg msgs[], int num)
{
	struct omap_i2c_dev *dev = i2c_get_adapdata(adap);
	int i;
	int r;

	omap_i2c_unidle(dev);

	r = omap_i2c_wait_for_bb(dev);
	if (r < 0)
		goto out;

	for (i = 0; i < num; i++) {
		r = omap_i2c_xfer_msg(adap, &msgs[i], (i == (num - 1)));
		if (r != 0)
			break;
	}

	if (r == 0)
		r = num;
out:
	omap_i2c_idle(dev);
	return r;
}

static u32
omap_i2c_func(struct i2c_adapter *adap)
{
	return I2C_FUNC_I2C | (I2C_FUNC_SMBUS_EMUL & ~I2C_FUNC_SMBUS_QUICK);
}

static inline void
omap_i2c_complete_cmd(struct omap_i2c_dev *dev, u16 err)
{
	dev->cmd_err |= err;
	complete(&dev->cmd_complete);
}

static inline void
omap_i2c_ack_stat(struct omap_i2c_dev *dev, u16 stat)
{
	omap_i2c_write_reg(dev, OMAP_I2C_STAT_REG, stat);
}

/* rev1 devices are apparently only on some 15xx */
#ifdef CONFIG_ARCH_OMAP15XX

static irqreturn_t
omap_i2c_rev1_isr(int this_irq, void *dev_id)
{
	struct omap_i2c_dev *dev = dev_id;
	u16 iv, w;

	if (dev->idle)
		return IRQ_NONE;

	iv = omap_i2c_read_reg(dev, OMAP_I2C_IV_REG);
	switch (iv) {
	case 0x00:	/* None */
		break;
	case 0x01:	/* Arbitration lost */
		dev_err(dev->dev, "Arbitration lost\n");
		omap_i2c_complete_cmd(dev, OMAP_I2C_STAT_AL);
		break;
	case 0x02:	/* No acknowledgement */
		omap_i2c_complete_cmd(dev, OMAP_I2C_STAT_NACK);
		omap_i2c_write_reg(dev, OMAP_I2C_CON_REG, OMAP_I2C_CON_STP);
		break;
	case 0x03:	/* Register access ready */
		omap_i2c_complete_cmd(dev, 0);
		break;
	case 0x04:	/* Receive data ready */
		if (dev->buf_len) {
			w = omap_i2c_read_reg(dev, OMAP_I2C_DATA_REG);
			*dev->buf++ = w;
			dev->buf_len--;
			if (dev->buf_len) {
				*dev->buf++ = w >> 8;
				dev->buf_len--;
			}
		} else
			dev_err(dev->dev, "RRDY IRQ while no data requested\n");
		break;
	case 0x05:	/* Transmit data ready */
		if (dev->buf_len) {
			w = *dev->buf++;
			dev->buf_len--;
			if (dev->buf_len) {
				w |= *dev->buf++ << 8;
				dev->buf_len--;
			}
			omap_i2c_write_reg(dev, OMAP_I2C_DATA_REG, w);
		} else
			dev_err(dev->dev, "XRDY IRQ while no data to send\n");
		break;
	default:
		return IRQ_NONE;
	}

	return IRQ_HANDLED;
}
#else
#define omap_i2c_rev1_isr		NULL
#endif

static irqreturn_t
omap_i2c_isr(int this_irq, void *dev_id)
{
	struct omap_i2c_dev *dev = dev_id;
	u16 bits;
	u16 stat, w;
	int err, count = 0;

	if (dev->idle)
		return IRQ_NONE;

	bits = omap_i2c_read_reg(dev, OMAP_I2C_IE_REG);
	while ((stat = (omap_i2c_read_reg(dev, OMAP_I2C_STAT_REG))) & bits) {
		dev_dbg(dev->dev, "IRQ (ISR = 0x%04x)\n", stat);
		if (count++ == 100) {
			dev_warn(dev->dev, "Too much work in one IRQ\n");
			break;
		}

		omap_i2c_write_reg(dev, OMAP_I2C_STAT_REG, stat);

		err = 0;
		if (stat & OMAP_I2C_STAT_NACK) {
			err |= OMAP_I2C_STAT_NACK;
			omap_i2c_write_reg(dev, OMAP_I2C_CON_REG,
					   OMAP_I2C_CON_STP);
		}
		if (stat & OMAP_I2C_STAT_AL) {
			dev_err(dev->dev, "Arbitration lost\n");
			err |= OMAP_I2C_STAT_AL;
		}
		if (stat & (OMAP_I2C_STAT_ARDY | OMAP_I2C_STAT_NACK |
					OMAP_I2C_STAT_AL))
			omap_i2c_complete_cmd(dev, err);
		if (stat & (OMAP_I2C_STAT_RRDY | OMAP_I2C_STAT_RDR)) {
			u8 num_bytes = 1;
			if (dev->fifo_size) {
				if (stat & OMAP_I2C_STAT_RRDY)
					num_bytes = dev->fifo_size;
				else
					num_bytes = omap_i2c_read_reg(dev,
							OMAP_I2C_BUFSTAT_REG);
			}
			while (num_bytes) {
				num_bytes--;
				w = omap_i2c_read_reg(dev, OMAP_I2C_DATA_REG);
				if (dev->buf_len) {
					*dev->buf++ = w;
					dev->buf_len--;
					/* Data reg from 2430 is 8 bit wide */
					if (!cpu_is_omap2430() &&
							!cpu_is_omap34xx()) {
						if (dev->buf_len) {
							*dev->buf++ = w >> 8;
							dev->buf_len--;
						}
					}
				} else {
					if (stat & OMAP_I2C_STAT_RRDY)
						dev_err(dev->dev,
							"RRDY IRQ while no data"
								" requested\n");
					if (stat & OMAP_I2C_STAT_RDR)
						dev_err(dev->dev,
							"RDR IRQ while no data"
								" requested\n");
					break;
				}
			}
			omap_i2c_ack_stat(dev,
				stat & (OMAP_I2C_STAT_RRDY | OMAP_I2C_STAT_RDR));
			continue;
		}
		if (stat & (OMAP_I2C_STAT_XRDY | OMAP_I2C_STAT_XDR)) {
			u8 num_bytes = 1;
			if (dev->fifo_size) {
				if (stat & OMAP_I2C_STAT_XRDY)
					num_bytes = dev->fifo_size;
				else
					num_bytes = omap_i2c_read_reg(dev,
							OMAP_I2C_BUFSTAT_REG);
			}
			while (num_bytes) {
				num_bytes--;
				w = 0;
				if (dev->buf_len) {
					w = *dev->buf++;
					dev->buf_len--;
					/* Data reg from  2430 is 8 bit wide */
					if (!cpu_is_omap2430() &&
							!cpu_is_omap34xx()) {
						if (dev->buf_len) {
							w |= *dev->buf++ << 8;
							dev->buf_len--;
						}
					}
				} else {
					if (stat & OMAP_I2C_STAT_XRDY)
						dev_err(dev->dev,
							"XRDY IRQ while no "
							"data to send\n");
					if (stat & OMAP_I2C_STAT_XDR)
						dev_err(dev->dev,
							"XDR IRQ while no "
							"data to send\n");
					break;
				}
				omap_i2c_write_reg(dev, OMAP_I2C_DATA_REG, w);
			}
			omap_i2c_ack_stat(dev,
				stat & (OMAP_I2C_STAT_XRDY | OMAP_I2C_STAT_XDR));
			continue;
		}
		if (stat & OMAP_I2C_STAT_ROVR) {
			dev_err(dev->dev, "Receive overrun\n");
			dev->cmd_err |= OMAP_I2C_STAT_ROVR;
		}
		if (stat & OMAP_I2C_STAT_XUDF) {
			dev_err(dev->dev, "Transmit underflow\n");
			dev->cmd_err |= OMAP_I2C_STAT_XUDF;
		}
	}

	return count ? IRQ_HANDLED : IRQ_NONE;
}

static const struct i2c_algorithm omap_i2c_algo = {
	.master_xfer	= omap_i2c_xfer,
	.functionality	= omap_i2c_func,
};

static int __init
omap_i2c_probe(struct platform_device *pdev)
{
	struct omap_i2c_dev	*dev;
	struct i2c_adapter	*adap;
	struct resource		*mem, *irq, *ioarea;
	irq_handler_t isr;
	int r;
	u32 speed = 0;

	/* NOTE: driver uses the static register mapping */
	mem = platform_get_resource(pdev, IORESOURCE_MEM, 0);
	if (!mem) {
		dev_err(&pdev->dev, "no mem resource?\n");
		return -ENODEV;
	}
	irq = platform_get_resource(pdev, IORESOURCE_IRQ, 0);
	if (!irq) {
		dev_err(&pdev->dev, "no irq resource?\n");
		return -ENODEV;
	}

	ioarea = request_mem_region(mem->start, (mem->end - mem->start) + 1,
			pdev->name);
	if (!ioarea) {
		dev_err(&pdev->dev, "I2C region already claimed\n");
		return -EBUSY;
	}

	dev = kzalloc(sizeof(struct omap_i2c_dev), GFP_KERNEL);
	if (!dev) {
		r = -ENOMEM;
		goto err_release_region;
	}

	if (pdev->dev.platform_data != NULL)
		speed = *(u32 *)pdev->dev.platform_data;
	else
		speed = 100;	/* Defualt speed */

	dev->speed = speed;
	dev->idle = 1;
	dev->dev = &pdev->dev;
	dev->irq = irq->start;
	dev->base = ioremap(mem->start, mem->end - mem->start + 1);
	if (!dev->base) {
		r = -ENOMEM;
		goto err_free_mem;
	}

	platform_set_drvdata(pdev, dev);

	if ((r = omap_i2c_get_clocks(dev)) != 0)
		goto err_iounmap;

	omap_i2c_unidle(dev);

	dev->rev = omap_i2c_read_reg(dev, OMAP_I2C_REV_REG) & 0xff;

	if (cpu_is_omap2430() || cpu_is_omap34xx()) {
		u16 s;

		/* Set up the fifo size - Get total size */
		s = (omap_i2c_read_reg(dev, OMAP_I2C_BUFSTAT_REG) >> 14) & 0x3;
		dev->fifo_size = 0x8 << s;

		/*
		 * Set up notification threshold as half the total available
		 * size. This is to ensure that we can handle the status on int
		 * call back latencies.
		 */
		dev->fifo_size = (dev->fifo_size / 2);
		dev->b_hw = 1; /* Enable hardware fixes */
	}

	/* reset ASAP, clearing any IRQs */
	omap_i2c_init(dev);

	isr = (dev->rev < OMAP_I2C_REV_2) ? omap_i2c_rev1_isr : omap_i2c_isr;
	r = request_irq(dev->irq, isr, 0, pdev->name, dev);

	if (r) {
		dev_err(dev->dev, "failure requesting irq %i\n", dev->irq);
		goto err_unuse_clocks;
	}

	dev_info(dev->dev, "bus %d rev%d.%d at %d kHz\n",
		 pdev->id, dev->rev >> 4, dev->rev & 0xf, dev->speed);

	omap_i2c_idle(dev);

	adap = &dev->adapter;
	i2c_set_adapdata(adap, dev);
	adap->owner = THIS_MODULE;
	adap->class = I2C_CLASS_HWMON;
	strncpy(adap->name, "OMAP I2C adapter", sizeof(adap->name));
	adap->algo = &omap_i2c_algo;
	adap->dev.parent = &pdev->dev;

	/* i2c device drivers may be active on return from add_adapter() */
	adap->nr = pdev->id;
	r = i2c_add_numbered_adapter(adap);
	if (r) {
		dev_err(dev->dev, "failure adding adapter\n");
		goto err_free_irq;
	}

	return 0;

err_free_irq:
	free_irq(dev->irq, dev);
err_unuse_clocks:
	omap_i2c_write_reg(dev, OMAP_I2C_CON_REG, 0);
	omap_i2c_idle(dev);
	omap_i2c_put_clocks(dev);
err_iounmap:
	iounmap(dev->base);
err_free_mem:
	platform_set_drvdata(pdev, NULL);
	kfree(dev);
err_release_region:
	release_mem_region(mem->start, (mem->end - mem->start) + 1);

	return r;
}

static int
omap_i2c_remove(struct platform_device *pdev)
{
	struct omap_i2c_dev	*dev = platform_get_drvdata(pdev);
	struct resource		*mem;

	platform_set_drvdata(pdev, NULL);

	free_irq(dev->irq, dev);
	i2c_del_adapter(&dev->adapter);
	omap_i2c_write_reg(dev, OMAP_I2C_CON_REG, 0);
	omap_i2c_put_clocks(dev);
	iounmap(dev->base);
	kfree(dev);
	mem = platform_get_resource(pdev, IORESOURCE_MEM, 0);
	release_mem_region(mem->start, (mem->end - mem->start) + 1);
	return 0;
}

static struct platform_driver omap_i2c_driver = {
	.probe		= omap_i2c_probe,
	.remove		= omap_i2c_remove,
	.driver		= {
		.name	= "i2c_omap",
		.owner	= THIS_MODULE,
	},
};

/* I2C may be needed to bring up other drivers */
static int __init
omap_i2c_init_driver(void)
{
	return platform_driver_register(&omap_i2c_driver);
}
subsys_initcall(omap_i2c_init_driver);

static void __exit omap_i2c_exit_driver(void)
{
	platform_driver_unregister(&omap_i2c_driver);
}
module_exit(omap_i2c_exit_driver);

MODULE_AUTHOR("MontaVista Software, Inc. (and others)");
MODULE_DESCRIPTION("TI OMAP I2C bus adapter");
MODULE_LICENSE("GPL");
MODULE_ALIAS("platform:i2c_omap");
OpenPOWER on IntegriCloud