summaryrefslogtreecommitdiffstats
path: root/drivers/i2c/busses/i2c-mv64xxx.c
blob: b1f42bf409638f166f592eba381ac9848dccb46a (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
/*
 * Driver for the i2c controller on the Marvell line of host bridges
 * (e.g, gt642[46]0, mv643[46]0, mv644[46]0, and Orion SoC family).
 *
 * Author: Mark A. Greer <mgreer@mvista.com>
 *
 * 2005 (c) MontaVista, Software, Inc.  This file is licensed under
 * the terms of the GNU General Public License version 2.  This program
 * is licensed "as is" without any warranty of any kind, whether express
 * or implied.
 */
#include <linux/kernel.h>
#include <linux/slab.h>
#include <linux/module.h>
#include <linux/spinlock.h>
#include <linux/i2c.h>
#include <linux/interrupt.h>
#include <linux/mv643xx_i2c.h>
#include <linux/platform_device.h>
#include <linux/io.h>
#include <linux/of.h>
#include <linux/of_device.h>
#include <linux/of_irq.h>
#include <linux/of_i2c.h>
#include <linux/clk.h>
#include <linux/err.h>

#define MV64XXX_I2C_ADDR_ADDR(val)			((val & 0x7f) << 1)
#define MV64XXX_I2C_BAUD_DIV_N(val)			(val & 0x7)
#define MV64XXX_I2C_BAUD_DIV_M(val)			((val & 0xf) << 3)

#define	MV64XXX_I2C_REG_CONTROL_ACK			0x00000004
#define	MV64XXX_I2C_REG_CONTROL_IFLG			0x00000008
#define	MV64XXX_I2C_REG_CONTROL_STOP			0x00000010
#define	MV64XXX_I2C_REG_CONTROL_START			0x00000020
#define	MV64XXX_I2C_REG_CONTROL_TWSIEN			0x00000040
#define	MV64XXX_I2C_REG_CONTROL_INTEN			0x00000080

/* Ctlr status values */
#define	MV64XXX_I2C_STATUS_BUS_ERR			0x00
#define	MV64XXX_I2C_STATUS_MAST_START			0x08
#define	MV64XXX_I2C_STATUS_MAST_REPEAT_START		0x10
#define	MV64XXX_I2C_STATUS_MAST_WR_ADDR_ACK		0x18
#define	MV64XXX_I2C_STATUS_MAST_WR_ADDR_NO_ACK		0x20
#define	MV64XXX_I2C_STATUS_MAST_WR_ACK			0x28
#define	MV64XXX_I2C_STATUS_MAST_WR_NO_ACK		0x30
#define	MV64XXX_I2C_STATUS_MAST_LOST_ARB		0x38
#define	MV64XXX_I2C_STATUS_MAST_RD_ADDR_ACK		0x40
#define	MV64XXX_I2C_STATUS_MAST_RD_ADDR_NO_ACK		0x48
#define	MV64XXX_I2C_STATUS_MAST_RD_DATA_ACK		0x50
#define	MV64XXX_I2C_STATUS_MAST_RD_DATA_NO_ACK		0x58
#define	MV64XXX_I2C_STATUS_MAST_WR_ADDR_2_ACK		0xd0
#define	MV64XXX_I2C_STATUS_MAST_WR_ADDR_2_NO_ACK	0xd8
#define	MV64XXX_I2C_STATUS_MAST_RD_ADDR_2_ACK		0xe0
#define	MV64XXX_I2C_STATUS_MAST_RD_ADDR_2_NO_ACK	0xe8
#define	MV64XXX_I2C_STATUS_NO_STATUS			0xf8

/* Driver states */
enum {
	MV64XXX_I2C_STATE_INVALID,
	MV64XXX_I2C_STATE_IDLE,
	MV64XXX_I2C_STATE_WAITING_FOR_START_COND,
	MV64XXX_I2C_STATE_WAITING_FOR_RESTART,
	MV64XXX_I2C_STATE_WAITING_FOR_ADDR_1_ACK,
	MV64XXX_I2C_STATE_WAITING_FOR_ADDR_2_ACK,
	MV64XXX_I2C_STATE_WAITING_FOR_SLAVE_ACK,
	MV64XXX_I2C_STATE_WAITING_FOR_SLAVE_DATA,
};

/* Driver actions */
enum {
	MV64XXX_I2C_ACTION_INVALID,
	MV64XXX_I2C_ACTION_CONTINUE,
	MV64XXX_I2C_ACTION_SEND_START,
	MV64XXX_I2C_ACTION_SEND_RESTART,
	MV64XXX_I2C_ACTION_SEND_ADDR_1,
	MV64XXX_I2C_ACTION_SEND_ADDR_2,
	MV64XXX_I2C_ACTION_SEND_DATA,
	MV64XXX_I2C_ACTION_RCV_DATA,
	MV64XXX_I2C_ACTION_RCV_DATA_STOP,
	MV64XXX_I2C_ACTION_SEND_STOP,
};

struct mv64xxx_i2c_regs {
	u8	addr;
	u8	ext_addr;
	u8	data;
	u8	control;
	u8	status;
	u8	clock;
	u8	soft_reset;
};

struct mv64xxx_i2c_data {
	struct i2c_msg		*msgs;
	int			num_msgs;
	int			irq;
	u32			state;
	u32			action;
	u32			aborting;
	u32			cntl_bits;
	void __iomem		*reg_base;
	struct mv64xxx_i2c_regs	reg_offsets;
	u32			addr1;
	u32			addr2;
	u32			bytes_left;
	u32			byte_posn;
	u32			send_stop;
	u32			block;
	int			rc;
	u32			freq_m;
	u32			freq_n;
#if defined(CONFIG_HAVE_CLK)
	struct clk              *clk;
#endif
	wait_queue_head_t	waitq;
	spinlock_t		lock;
	struct i2c_msg		*msg;
	struct i2c_adapter	adapter;
};

static struct mv64xxx_i2c_regs mv64xxx_i2c_regs_mv64xxx = {
	.addr		= 0x00,
	.ext_addr	= 0x10,
	.data		= 0x04,
	.control	= 0x08,
	.status		= 0x0c,
	.clock		= 0x0c,
	.soft_reset	= 0x1c,
};

static struct mv64xxx_i2c_regs mv64xxx_i2c_regs_sun4i = {
	.addr		= 0x00,
	.ext_addr	= 0x04,
	.data		= 0x08,
	.control	= 0x0c,
	.status		= 0x10,
	.clock		= 0x14,
	.soft_reset	= 0x18,
};

static void
mv64xxx_i2c_prepare_for_io(struct mv64xxx_i2c_data *drv_data,
	struct i2c_msg *msg)
{
	u32	dir = 0;

	drv_data->msg = msg;
	drv_data->byte_posn = 0;
	drv_data->bytes_left = msg->len;
	drv_data->aborting = 0;
	drv_data->rc = 0;
	drv_data->cntl_bits = MV64XXX_I2C_REG_CONTROL_ACK |
		MV64XXX_I2C_REG_CONTROL_INTEN | MV64XXX_I2C_REG_CONTROL_TWSIEN;

	if (msg->flags & I2C_M_RD)
		dir = 1;

	if (msg->flags & I2C_M_TEN) {
		drv_data->addr1 = 0xf0 | (((u32)msg->addr & 0x300) >> 7) | dir;
		drv_data->addr2 = (u32)msg->addr & 0xff;
	} else {
		drv_data->addr1 = MV64XXX_I2C_ADDR_ADDR((u32)msg->addr) | dir;
		drv_data->addr2 = 0;
	}
}

/*
 *****************************************************************************
 *
 *	Finite State Machine & Interrupt Routines
 *
 *****************************************************************************
 */

/* Reset hardware and initialize FSM */
static void
mv64xxx_i2c_hw_init(struct mv64xxx_i2c_data *drv_data)
{
	writel(0, drv_data->reg_base + drv_data->reg_offsets.soft_reset);
	writel(MV64XXX_I2C_BAUD_DIV_M(drv_data->freq_m) | MV64XXX_I2C_BAUD_DIV_N(drv_data->freq_n),
		drv_data->reg_base + drv_data->reg_offsets.clock);
	writel(0, drv_data->reg_base + drv_data->reg_offsets.addr);
	writel(0, drv_data->reg_base + drv_data->reg_offsets.ext_addr);
	writel(MV64XXX_I2C_REG_CONTROL_TWSIEN | MV64XXX_I2C_REG_CONTROL_STOP,
		drv_data->reg_base + drv_data->reg_offsets.control);
	drv_data->state = MV64XXX_I2C_STATE_IDLE;
}

static void
mv64xxx_i2c_fsm(struct mv64xxx_i2c_data *drv_data, u32 status)
{
	/*
	 * If state is idle, then this is likely the remnants of an old
	 * operation that driver has given up on or the user has killed.
	 * If so, issue the stop condition and go to idle.
	 */
	if (drv_data->state == MV64XXX_I2C_STATE_IDLE) {
		drv_data->action = MV64XXX_I2C_ACTION_SEND_STOP;
		return;
	}

	/* The status from the ctlr [mostly] tells us what to do next */
	switch (status) {
	/* Start condition interrupt */
	case MV64XXX_I2C_STATUS_MAST_START: /* 0x08 */
	case MV64XXX_I2C_STATUS_MAST_REPEAT_START: /* 0x10 */
		drv_data->action = MV64XXX_I2C_ACTION_SEND_ADDR_1;
		drv_data->state = MV64XXX_I2C_STATE_WAITING_FOR_ADDR_1_ACK;
		break;

	/* Performing a write */
	case MV64XXX_I2C_STATUS_MAST_WR_ADDR_ACK: /* 0x18 */
		if (drv_data->msg->flags & I2C_M_TEN) {
			drv_data->action = MV64XXX_I2C_ACTION_SEND_ADDR_2;
			drv_data->state =
				MV64XXX_I2C_STATE_WAITING_FOR_ADDR_2_ACK;
			break;
		}
		/* FALLTHRU */
	case MV64XXX_I2C_STATUS_MAST_WR_ADDR_2_ACK: /* 0xd0 */
	case MV64XXX_I2C_STATUS_MAST_WR_ACK: /* 0x28 */
		if ((drv_data->bytes_left == 0)
				|| (drv_data->aborting
					&& (drv_data->byte_posn != 0))) {
			if (drv_data->send_stop || drv_data->aborting) {
				drv_data->action = MV64XXX_I2C_ACTION_SEND_STOP;
				drv_data->state = MV64XXX_I2C_STATE_IDLE;
			} else {
				drv_data->action =
					MV64XXX_I2C_ACTION_SEND_RESTART;
				drv_data->state =
					MV64XXX_I2C_STATE_WAITING_FOR_RESTART;
			}
		} else {
			drv_data->action = MV64XXX_I2C_ACTION_SEND_DATA;
			drv_data->state =
				MV64XXX_I2C_STATE_WAITING_FOR_SLAVE_ACK;
			drv_data->bytes_left--;
		}
		break;

	/* Performing a read */
	case MV64XXX_I2C_STATUS_MAST_RD_ADDR_ACK: /* 40 */
		if (drv_data->msg->flags & I2C_M_TEN) {
			drv_data->action = MV64XXX_I2C_ACTION_SEND_ADDR_2;
			drv_data->state =
				MV64XXX_I2C_STATE_WAITING_FOR_ADDR_2_ACK;
			break;
		}
		/* FALLTHRU */
	case MV64XXX_I2C_STATUS_MAST_RD_ADDR_2_ACK: /* 0xe0 */
		if (drv_data->bytes_left == 0) {
			drv_data->action = MV64XXX_I2C_ACTION_SEND_STOP;
			drv_data->state = MV64XXX_I2C_STATE_IDLE;
			break;
		}
		/* FALLTHRU */
	case MV64XXX_I2C_STATUS_MAST_RD_DATA_ACK: /* 0x50 */
		if (status != MV64XXX_I2C_STATUS_MAST_RD_DATA_ACK)
			drv_data->action = MV64XXX_I2C_ACTION_CONTINUE;
		else {
			drv_data->action = MV64XXX_I2C_ACTION_RCV_DATA;
			drv_data->bytes_left--;
		}
		drv_data->state = MV64XXX_I2C_STATE_WAITING_FOR_SLAVE_DATA;

		if ((drv_data->bytes_left == 1) || drv_data->aborting)
			drv_data->cntl_bits &= ~MV64XXX_I2C_REG_CONTROL_ACK;
		break;

	case MV64XXX_I2C_STATUS_MAST_RD_DATA_NO_ACK: /* 0x58 */
		drv_data->action = MV64XXX_I2C_ACTION_RCV_DATA_STOP;
		drv_data->state = MV64XXX_I2C_STATE_IDLE;
		break;

	case MV64XXX_I2C_STATUS_MAST_WR_ADDR_NO_ACK: /* 0x20 */
	case MV64XXX_I2C_STATUS_MAST_WR_NO_ACK: /* 30 */
	case MV64XXX_I2C_STATUS_MAST_RD_ADDR_NO_ACK: /* 48 */
		/* Doesn't seem to be a device at other end */
		drv_data->action = MV64XXX_I2C_ACTION_SEND_STOP;
		drv_data->state = MV64XXX_I2C_STATE_IDLE;
		drv_data->rc = -ENXIO;
		break;

	default:
		dev_err(&drv_data->adapter.dev,
			"mv64xxx_i2c_fsm: Ctlr Error -- state: 0x%x, "
			"status: 0x%x, addr: 0x%x, flags: 0x%x\n",
			 drv_data->state, status, drv_data->msg->addr,
			 drv_data->msg->flags);
		drv_data->action = MV64XXX_I2C_ACTION_SEND_STOP;
		mv64xxx_i2c_hw_init(drv_data);
		drv_data->rc = -EIO;
	}
}

static void
mv64xxx_i2c_do_action(struct mv64xxx_i2c_data *drv_data)
{
	switch(drv_data->action) {
	case MV64XXX_I2C_ACTION_SEND_RESTART:
		/* We should only get here if we have further messages */
		BUG_ON(drv_data->num_msgs == 0);

		drv_data->cntl_bits |= MV64XXX_I2C_REG_CONTROL_START;
		writel(drv_data->cntl_bits,
			drv_data->reg_base + drv_data->reg_offsets.control);

		drv_data->msgs++;
		drv_data->num_msgs--;

		/* Setup for the next message */
		mv64xxx_i2c_prepare_for_io(drv_data, drv_data->msgs);

		/*
		 * We're never at the start of the message here, and by this
		 * time it's already too late to do any protocol mangling.
		 * Thankfully, do not advertise support for that feature.
		 */
		drv_data->send_stop = drv_data->num_msgs == 1;
		break;

	case MV64XXX_I2C_ACTION_CONTINUE:
		writel(drv_data->cntl_bits,
			drv_data->reg_base + drv_data->reg_offsets.control);
		break;

	case MV64XXX_I2C_ACTION_SEND_START:
		writel(drv_data->cntl_bits | MV64XXX_I2C_REG_CONTROL_START,
			drv_data->reg_base + drv_data->reg_offsets.control);
		break;

	case MV64XXX_I2C_ACTION_SEND_ADDR_1:
		writel(drv_data->addr1,
			drv_data->reg_base + drv_data->reg_offsets.data);
		writel(drv_data->cntl_bits,
			drv_data->reg_base + drv_data->reg_offsets.control);
		break;

	case MV64XXX_I2C_ACTION_SEND_ADDR_2:
		writel(drv_data->addr2,
			drv_data->reg_base + drv_data->reg_offsets.data);
		writel(drv_data->cntl_bits,
			drv_data->reg_base + drv_data->reg_offsets.control);
		break;

	case MV64XXX_I2C_ACTION_SEND_DATA:
		writel(drv_data->msg->buf[drv_data->byte_posn++],
			drv_data->reg_base + drv_data->reg_offsets.data);
		writel(drv_data->cntl_bits,
			drv_data->reg_base + drv_data->reg_offsets.control);
		break;

	case MV64XXX_I2C_ACTION_RCV_DATA:
		drv_data->msg->buf[drv_data->byte_posn++] =
			readl(drv_data->reg_base + drv_data->reg_offsets.data);
		writel(drv_data->cntl_bits,
			drv_data->reg_base + drv_data->reg_offsets.control);
		break;

	case MV64XXX_I2C_ACTION_RCV_DATA_STOP:
		drv_data->msg->buf[drv_data->byte_posn++] =
			readl(drv_data->reg_base + drv_data->reg_offsets.data);
		drv_data->cntl_bits &= ~MV64XXX_I2C_REG_CONTROL_INTEN;
		writel(drv_data->cntl_bits | MV64XXX_I2C_REG_CONTROL_STOP,
			drv_data->reg_base + drv_data->reg_offsets.control);
		drv_data->block = 0;
		wake_up(&drv_data->waitq);
		break;

	case MV64XXX_I2C_ACTION_INVALID:
	default:
		dev_err(&drv_data->adapter.dev,
			"mv64xxx_i2c_do_action: Invalid action: %d\n",
			drv_data->action);
		drv_data->rc = -EIO;
		/* FALLTHRU */
	case MV64XXX_I2C_ACTION_SEND_STOP:
		drv_data->cntl_bits &= ~MV64XXX_I2C_REG_CONTROL_INTEN;
		writel(drv_data->cntl_bits | MV64XXX_I2C_REG_CONTROL_STOP,
			drv_data->reg_base + drv_data->reg_offsets.control);
		drv_data->block = 0;
		wake_up(&drv_data->waitq);
		break;
	}
}

static irqreturn_t
mv64xxx_i2c_intr(int irq, void *dev_id)
{
	struct mv64xxx_i2c_data	*drv_data = dev_id;
	unsigned long	flags;
	u32		status;
	irqreturn_t	rc = IRQ_NONE;

	spin_lock_irqsave(&drv_data->lock, flags);
	while (readl(drv_data->reg_base + drv_data->reg_offsets.control) &
						MV64XXX_I2C_REG_CONTROL_IFLG) {
		status = readl(drv_data->reg_base + drv_data->reg_offsets.status);
		mv64xxx_i2c_fsm(drv_data, status);
		mv64xxx_i2c_do_action(drv_data);
		rc = IRQ_HANDLED;
	}
	spin_unlock_irqrestore(&drv_data->lock, flags);

	return rc;
}

/*
 *****************************************************************************
 *
 *	I2C Msg Execution Routines
 *
 *****************************************************************************
 */
static void
mv64xxx_i2c_wait_for_completion(struct mv64xxx_i2c_data *drv_data)
{
	long		time_left;
	unsigned long	flags;
	char		abort = 0;

	time_left = wait_event_timeout(drv_data->waitq,
		!drv_data->block, drv_data->adapter.timeout);

	spin_lock_irqsave(&drv_data->lock, flags);
	if (!time_left) { /* Timed out */
		drv_data->rc = -ETIMEDOUT;
		abort = 1;
	} else if (time_left < 0) { /* Interrupted/Error */
		drv_data->rc = time_left; /* errno value */
		abort = 1;
	}

	if (abort && drv_data->block) {
		drv_data->aborting = 1;
		spin_unlock_irqrestore(&drv_data->lock, flags);

		time_left = wait_event_timeout(drv_data->waitq,
			!drv_data->block, drv_data->adapter.timeout);

		if ((time_left <= 0) && drv_data->block) {
			drv_data->state = MV64XXX_I2C_STATE_IDLE;
			dev_err(&drv_data->adapter.dev,
				"mv64xxx: I2C bus locked, block: %d, "
				"time_left: %d\n", drv_data->block,
				(int)time_left);
			mv64xxx_i2c_hw_init(drv_data);
		}
	} else
		spin_unlock_irqrestore(&drv_data->lock, flags);
}

static int
mv64xxx_i2c_execute_msg(struct mv64xxx_i2c_data *drv_data, struct i2c_msg *msg,
				int is_last)
{
	unsigned long	flags;

	spin_lock_irqsave(&drv_data->lock, flags);
	mv64xxx_i2c_prepare_for_io(drv_data, msg);

	drv_data->action = MV64XXX_I2C_ACTION_SEND_START;
	drv_data->state = MV64XXX_I2C_STATE_WAITING_FOR_START_COND;

	drv_data->send_stop = is_last;
	drv_data->block = 1;
	mv64xxx_i2c_do_action(drv_data);
	spin_unlock_irqrestore(&drv_data->lock, flags);

	mv64xxx_i2c_wait_for_completion(drv_data);
	return drv_data->rc;
}

/*
 *****************************************************************************
 *
 *	I2C Core Support Routines (Interface to higher level I2C code)
 *
 *****************************************************************************
 */
static u32
mv64xxx_i2c_functionality(struct i2c_adapter *adap)
{
	return I2C_FUNC_I2C | I2C_FUNC_10BIT_ADDR | I2C_FUNC_SMBUS_EMUL;
}

static int
mv64xxx_i2c_xfer(struct i2c_adapter *adap, struct i2c_msg msgs[], int num)
{
	struct mv64xxx_i2c_data *drv_data = i2c_get_adapdata(adap);
	int rc, ret = num;

	BUG_ON(drv_data->msgs != NULL);
	drv_data->msgs = msgs;
	drv_data->num_msgs = num;

	rc = mv64xxx_i2c_execute_msg(drv_data, &msgs[0], num == 1);
	if (rc < 0)
		ret = rc;

	drv_data->num_msgs = 0;
	drv_data->msgs = NULL;

	return ret;
}

static const struct i2c_algorithm mv64xxx_i2c_algo = {
	.master_xfer = mv64xxx_i2c_xfer,
	.functionality = mv64xxx_i2c_functionality,
};

/*
 *****************************************************************************
 *
 *	Driver Interface & Early Init Routines
 *
 *****************************************************************************
 */
static const struct of_device_id mv64xxx_i2c_of_match_table[] = {
	{ .compatible = "allwinner,sun4i-i2c", .data = &mv64xxx_i2c_regs_sun4i},
	{ .compatible = "marvell,mv64xxx-i2c", .data = &mv64xxx_i2c_regs_mv64xxx},
	{}
};
MODULE_DEVICE_TABLE(of, mv64xxx_i2c_of_match_table);

#ifdef CONFIG_OF
static int
mv64xxx_calc_freq(const int tclk, const int n, const int m)
{
	return tclk / (10 * (m + 1) * (2 << n));
}

static bool
mv64xxx_find_baud_factors(const u32 req_freq, const u32 tclk, u32 *best_n,
			  u32 *best_m)
{
	int freq, delta, best_delta = INT_MAX;
	int m, n;

	for (n = 0; n <= 7; n++)
		for (m = 0; m <= 15; m++) {
			freq = mv64xxx_calc_freq(tclk, n, m);
			delta = req_freq - freq;
			if (delta >= 0 && delta < best_delta) {
				*best_m = m;
				*best_n = n;
				best_delta = delta;
			}
			if (best_delta == 0)
				return true;
		}
	if (best_delta == INT_MAX)
		return false;
	return true;
}

static int
mv64xxx_of_config(struct mv64xxx_i2c_data *drv_data,
		  struct device *dev)
{
	const struct of_device_id *device;
	struct device_node *np = dev->of_node;
	u32 bus_freq, tclk;
	int rc = 0;

	/* CLK is mandatory when using DT to describe the i2c bus. We
	 * need to know tclk in order to calculate bus clock
	 * factors.
	 */
#if !defined(CONFIG_HAVE_CLK)
	/* Have OF but no CLK */
	return -ENODEV;
#else
	if (IS_ERR(drv_data->clk)) {
		rc = -ENODEV;
		goto out;
	}
	tclk = clk_get_rate(drv_data->clk);

	rc = of_property_read_u32(np, "clock-frequency", &bus_freq);
	if (rc)
		bus_freq = 100000; /* 100kHz by default */

	if (!mv64xxx_find_baud_factors(bus_freq, tclk,
				       &drv_data->freq_n, &drv_data->freq_m)) {
		rc = -EINVAL;
		goto out;
	}
	drv_data->irq = irq_of_parse_and_map(np, 0);

	/* Its not yet defined how timeouts will be specified in device tree.
	 * So hard code the value to 1 second.
	 */
	drv_data->adapter.timeout = HZ;

	device = of_match_device(mv64xxx_i2c_of_match_table, dev);
	if (!device)
		return -ENODEV;

	memcpy(&drv_data->reg_offsets, device->data, sizeof(drv_data->reg_offsets));

out:
	return rc;
#endif
}
#else /* CONFIG_OF */
static int
mv64xxx_of_config(struct mv64xxx_i2c_data *drv_data,
		  struct device *dev)
{
	return -ENODEV;
}
#endif /* CONFIG_OF */

static int
mv64xxx_i2c_probe(struct platform_device *pd)
{
	struct mv64xxx_i2c_data		*drv_data;
	struct mv64xxx_i2c_pdata	*pdata = pd->dev.platform_data;
	struct resource	*r;
	int	rc;

	if ((!pdata && !pd->dev.of_node))
		return -ENODEV;

	drv_data = devm_kzalloc(&pd->dev, sizeof(struct mv64xxx_i2c_data),
				GFP_KERNEL);
	if (!drv_data)
		return -ENOMEM;

	r = platform_get_resource(pd, IORESOURCE_MEM, 0);
	drv_data->reg_base = devm_ioremap_resource(&pd->dev, r);
	if (IS_ERR(drv_data->reg_base))
		return PTR_ERR(drv_data->reg_base);

	strlcpy(drv_data->adapter.name, MV64XXX_I2C_CTLR_NAME " adapter",
		sizeof(drv_data->adapter.name));

	init_waitqueue_head(&drv_data->waitq);
	spin_lock_init(&drv_data->lock);

#if defined(CONFIG_HAVE_CLK)
	/* Not all platforms have a clk */
	drv_data->clk = devm_clk_get(&pd->dev, NULL);
	if (!IS_ERR(drv_data->clk)) {
		clk_prepare(drv_data->clk);
		clk_enable(drv_data->clk);
	}
#endif
	if (pdata) {
		drv_data->freq_m = pdata->freq_m;
		drv_data->freq_n = pdata->freq_n;
		drv_data->irq = platform_get_irq(pd, 0);
		drv_data->adapter.timeout = msecs_to_jiffies(pdata->timeout);
		memcpy(&drv_data->reg_offsets, &mv64xxx_i2c_regs_mv64xxx, sizeof(drv_data->reg_offsets));
	} else if (pd->dev.of_node) {
		rc = mv64xxx_of_config(drv_data, &pd->dev);
		if (rc)
			goto exit_clk;
	}
	if (drv_data->irq < 0) {
		rc = -ENXIO;
		goto exit_clk;
	}

	drv_data->adapter.dev.parent = &pd->dev;
	drv_data->adapter.algo = &mv64xxx_i2c_algo;
	drv_data->adapter.owner = THIS_MODULE;
	drv_data->adapter.class = I2C_CLASS_HWMON | I2C_CLASS_SPD;
	drv_data->adapter.nr = pd->id;
	drv_data->adapter.dev.of_node = pd->dev.of_node;
	platform_set_drvdata(pd, drv_data);
	i2c_set_adapdata(&drv_data->adapter, drv_data);

	mv64xxx_i2c_hw_init(drv_data);

	rc = request_irq(drv_data->irq, mv64xxx_i2c_intr, 0,
			 MV64XXX_I2C_CTLR_NAME, drv_data);
	if (rc) {
		dev_err(&drv_data->adapter.dev,
			"mv64xxx: Can't register intr handler irq%d: %d\n",
			drv_data->irq, rc);
		goto exit_clk;
	} else if ((rc = i2c_add_numbered_adapter(&drv_data->adapter)) != 0) {
		dev_err(&drv_data->adapter.dev,
			"mv64xxx: Can't add i2c adapter, rc: %d\n", -rc);
		goto exit_free_irq;
	}

	of_i2c_register_devices(&drv_data->adapter);

	return 0;

exit_free_irq:
	free_irq(drv_data->irq, drv_data);
exit_clk:
#if defined(CONFIG_HAVE_CLK)
	/* Not all platforms have a clk */
	if (!IS_ERR(drv_data->clk)) {
		clk_disable(drv_data->clk);
		clk_unprepare(drv_data->clk);
	}
#endif
	return rc;
}

static int
mv64xxx_i2c_remove(struct platform_device *dev)
{
	struct mv64xxx_i2c_data		*drv_data = platform_get_drvdata(dev);

	i2c_del_adapter(&drv_data->adapter);
	free_irq(drv_data->irq, drv_data);
#if defined(CONFIG_HAVE_CLK)
	/* Not all platforms have a clk */
	if (!IS_ERR(drv_data->clk)) {
		clk_disable(drv_data->clk);
		clk_unprepare(drv_data->clk);
	}
#endif

	return 0;
}

static struct platform_driver mv64xxx_i2c_driver = {
	.probe	= mv64xxx_i2c_probe,
	.remove	= mv64xxx_i2c_remove,
	.driver	= {
		.owner	= THIS_MODULE,
		.name	= MV64XXX_I2C_CTLR_NAME,
		.of_match_table = of_match_ptr(mv64xxx_i2c_of_match_table),
	},
};

module_platform_driver(mv64xxx_i2c_driver);

MODULE_AUTHOR("Mark A. Greer <mgreer@mvista.com>");
MODULE_DESCRIPTION("Marvell mv64xxx host bridge i2c ctlr driver");
MODULE_LICENSE("GPL");