summaryrefslogtreecommitdiff
path: root/drivers/i2c/busses/i2c-ocores.c
blob: e106af83cef4da5626e534325805aad70be2f617 (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
// SPDX-License-Identifier: GPL-2.0
/*
 * i2c-ocores.c: I2C bus driver for OpenCores I2C controller
 * (https://opencores.org/project/i2c/overview)
 *
 * Peter Korsgaard <peter@korsgaard.com>
 *
 * Support for the GRLIB port of the controller by
 * Andreas Larsson <andreas@gaisler.com>
 */

#include <linux/clk.h>
#include <linux/delay.h>
#include <linux/err.h>
#include <linux/kernel.h>
#include <linux/module.h>
#include <linux/errno.h>
#include <linux/platform_device.h>
#include <linux/i2c.h>
#include <linux/interrupt.h>
#include <linux/wait.h>
#include <linux/platform_data/i2c-ocores.h>
#include <linux/slab.h>
#include <linux/io.h>
#include <linux/log2.h>
#include <linux/spinlock.h>
#include <linux/jiffies.h>

/*
 * 'process_lock' exists because ocores_process() and ocores_process_timeout()
 * can't run in parallel.
 */
struct ocores_i2c {
	void __iomem *base;
	int iobase;
	u32 reg_shift;
	u32 reg_io_width;
	unsigned long flags;
	wait_queue_head_t wait;
	struct i2c_adapter adap;
	struct i2c_msg *msg;
	int pos;
	int nmsgs;
	int state; /* see STATE_ */
	spinlock_t process_lock;
	struct clk *clk;
	int ip_clock_khz;
	int bus_clock_khz;
	void (*setreg)(struct ocores_i2c *i2c, int reg, u8 value);
	u8 (*getreg)(struct ocores_i2c *i2c, int reg);
};

/* registers */
#define OCI2C_PRELOW		0
#define OCI2C_PREHIGH		1
#define OCI2C_CONTROL		2
#define OCI2C_DATA		3
#define OCI2C_CMD		4 /* write only */
#define OCI2C_STATUS		4 /* read only, same address as OCI2C_CMD */

#define OCI2C_CTRL_IEN		0x40
#define OCI2C_CTRL_EN		0x80

#define OCI2C_CMD_START		0x91
#define OCI2C_CMD_STOP		0x41
#define OCI2C_CMD_READ		0x21
#define OCI2C_CMD_WRITE		0x11
#define OCI2C_CMD_READ_ACK	0x21
#define OCI2C_CMD_READ_NACK	0x29
#define OCI2C_CMD_IACK		0x01

#define OCI2C_STAT_IF		0x01
#define OCI2C_STAT_TIP		0x02
#define OCI2C_STAT_ARBLOST	0x20
#define OCI2C_STAT_BUSY		0x40
#define OCI2C_STAT_NACK		0x80

#define STATE_DONE		0
#define STATE_START		1
#define STATE_WRITE		2
#define STATE_READ		3
#define STATE_ERROR		4

#define TYPE_OCORES		0
#define TYPE_GRLIB		1

#define OCORES_FLAG_BROKEN_IRQ BIT(1) /* Broken IRQ for FU540-C000 SoC */

static void oc_setreg_8(struct ocores_i2c *i2c, int reg, u8 value)
{
	iowrite8(value, i2c->base + (reg << i2c->reg_shift));
}

static void oc_setreg_16(struct ocores_i2c *i2c, int reg, u8 value)
{
	iowrite16(value, i2c->base + (reg << i2c->reg_shift));
}

static void oc_setreg_32(struct ocores_i2c *i2c, int reg, u8 value)
{
	iowrite32(value, i2c->base + (reg << i2c->reg_shift));
}

static void oc_setreg_16be(struct ocores_i2c *i2c, int reg, u8 value)
{
	iowrite16be(value, i2c->base + (reg << i2c->reg_shift));
}

static void oc_setreg_32be(struct ocores_i2c *i2c, int reg, u8 value)
{
	iowrite32be(value, i2c->base + (reg << i2c->reg_shift));
}

static inline u8 oc_getreg_8(struct ocores_i2c *i2c, int reg)
{
	return ioread8(i2c->base + (reg << i2c->reg_shift));
}

static inline u8 oc_getreg_16(struct ocores_i2c *i2c, int reg)
{
	return ioread16(i2c->base + (reg << i2c->reg_shift));
}

static inline u8 oc_getreg_32(struct ocores_i2c *i2c, int reg)
{
	return ioread32(i2c->base + (reg << i2c->reg_shift));
}

static inline u8 oc_getreg_16be(struct ocores_i2c *i2c, int reg)
{
	return ioread16be(i2c->base + (reg << i2c->reg_shift));
}

static inline u8 oc_getreg_32be(struct ocores_i2c *i2c, int reg)
{
	return ioread32be(i2c->base + (reg << i2c->reg_shift));
}

static void oc_setreg_io_8(struct ocores_i2c *i2c, int reg, u8 value)
{
	outb(value, i2c->iobase + reg);
}

static inline u8 oc_getreg_io_8(struct ocores_i2c *i2c, int reg)
{
	return inb(i2c->iobase + reg);
}

static inline void oc_setreg(struct ocores_i2c *i2c, int reg, u8 value)
{
	i2c->setreg(i2c, reg, value);
}

static inline u8 oc_getreg(struct ocores_i2c *i2c, int reg)
{
	return i2c->getreg(i2c, reg);
}

static void ocores_process(struct ocores_i2c *i2c, u8 stat)
{
	struct i2c_msg *msg = i2c->msg;
	unsigned long flags;

	/*
	 * If we spin here is because we are in timeout, so we are going
	 * to be in STATE_ERROR. See ocores_process_timeout()
	 */
	spin_lock_irqsave(&i2c->process_lock, flags);

	if ((i2c->state == STATE_DONE) || (i2c->state == STATE_ERROR)) {
		/* stop has been sent */
		oc_setreg(i2c, OCI2C_CMD, OCI2C_CMD_IACK);
		wake_up(&i2c->wait);
		goto out;
	}

	/* error? */
	if (stat & OCI2C_STAT_ARBLOST) {
		i2c->state = STATE_ERROR;
		oc_setreg(i2c, OCI2C_CMD, OCI2C_CMD_STOP);
		goto out;
	}

	if ((i2c->state == STATE_START) || (i2c->state == STATE_WRITE)) {
		i2c->state =
			(msg->flags & I2C_M_RD) ? STATE_READ : STATE_WRITE;

		if (stat & OCI2C_STAT_NACK) {
			i2c->state = STATE_ERROR;
			oc_setreg(i2c, OCI2C_CMD, OCI2C_CMD_STOP);
			goto out;
		}
	} else {
		msg->buf[i2c->pos++] = oc_getreg(i2c, OCI2C_DATA);
	}

	/* end of msg? */
	if (i2c->pos == msg->len) {
		i2c->nmsgs--;
		i2c->msg++;
		i2c->pos = 0;
		msg = i2c->msg;

		if (i2c->nmsgs) {	/* end? */
			/* send start? */
			if (!(msg->flags & I2C_M_NOSTART)) {
				u8 addr = i2c_8bit_addr_from_msg(msg);

				i2c->state = STATE_START;

				oc_setreg(i2c, OCI2C_DATA, addr);
				oc_setreg(i2c, OCI2C_CMD, OCI2C_CMD_START);
				goto out;
			}
			i2c->state = (msg->flags & I2C_M_RD)
				? STATE_READ : STATE_WRITE;
		} else {
			i2c->state = STATE_DONE;
			oc_setreg(i2c, OCI2C_CMD, OCI2C_CMD_STOP);
			goto out;
		}
	}

	if (i2c->state == STATE_READ) {
		oc_setreg(i2c, OCI2C_CMD, i2c->pos == (msg->len-1) ?
			  OCI2C_CMD_READ_NACK : OCI2C_CMD_READ_ACK);
	} else {
		oc_setreg(i2c, OCI2C_DATA, msg->buf[i2c->pos++]);
		oc_setreg(i2c, OCI2C_CMD, OCI2C_CMD_WRITE);
	}

out:
	spin_unlock_irqrestore(&i2c->process_lock, flags);
}

static irqreturn_t ocores_isr(int irq, void *dev_id)
{
	struct ocores_i2c *i2c = dev_id;
	u8 stat = oc_getreg(i2c, OCI2C_STATUS);

	if (i2c->flags & OCORES_FLAG_BROKEN_IRQ) {
		if ((stat & OCI2C_STAT_IF) && !(stat & OCI2C_STAT_BUSY))
			return IRQ_NONE;
	} else if (!(stat & OCI2C_STAT_IF)) {
		return IRQ_NONE;
	}
	ocores_process(i2c, stat);

	return IRQ_HANDLED;
}

/**
 * ocores_process_timeout() - Process timeout event
 * @i2c: ocores I2C device instance
 */
static void ocores_process_timeout(struct ocores_i2c *i2c)
{
	unsigned long flags;

	spin_lock_irqsave(&i2c->process_lock, flags);
	i2c->state = STATE_ERROR;
	oc_setreg(i2c, OCI2C_CMD, OCI2C_CMD_STOP);
	spin_unlock_irqrestore(&i2c->process_lock, flags);
}

/**
 * ocores_wait() - Wait until something change in a given register
 * @i2c: ocores I2C device instance
 * @reg: register to query
 * @mask: bitmask to apply on register value
 * @val: expected result
 * @timeout: timeout in jiffies
 *
 * Timeout is necessary to avoid to stay here forever when the chip
 * does not answer correctly.
 *
 * Return: 0 on success, -ETIMEDOUT on timeout
 */
static int ocores_wait(struct ocores_i2c *i2c,
		       int reg, u8 mask, u8 val,
		       const unsigned long timeout)
{
	unsigned long j;

	j = jiffies + timeout;
	while (1) {
		u8 status = oc_getreg(i2c, reg);

		if ((status & mask) == val)
			break;

		if (time_after(jiffies, j))
			return -ETIMEDOUT;
	}
	return 0;
}

/**
 * ocores_poll_wait() - Wait until is possible to process some data
 * @i2c: ocores I2C device instance
 *
 * Used when the device is in polling mode (interrupts disabled).
 *
 * Return: 0 on success, -ETIMEDOUT on timeout
 */
static int ocores_poll_wait(struct ocores_i2c *i2c)
{
	u8 mask;
	int err;

	if (i2c->state == STATE_DONE || i2c->state == STATE_ERROR) {
		/* transfer is over */
		mask = OCI2C_STAT_BUSY;
	} else {
		/* on going transfer */
		mask = OCI2C_STAT_TIP;
		/*
		 * We wait for the data to be transferred (8bit),
		 * then we start polling on the ACK/NACK bit
		 */
		udelay((8 * 1000) / i2c->bus_clock_khz);
	}

	/*
	 * once we are here we expect to get the expected result immediately
	 * so if after 1ms we timeout then something is broken.
	 */
	err = ocores_wait(i2c, OCI2C_STATUS, mask, 0, msecs_to_jiffies(1));
	if (err)
		dev_warn(i2c->adap.dev.parent,
			 "%s: STATUS timeout, bit 0x%x did not clear in 1ms\n",
			 __func__, mask);
	return err;
}

/**
 * ocores_process_polling() - It handles an IRQ-less transfer
 * @i2c: ocores I2C device instance
 *
 * Even if IRQ are disabled, the I2C OpenCore IP behavior is exactly the same
 * (only that IRQ are not produced). This means that we can re-use entirely
 * ocores_isr(), we just add our polling code around it.
 *
 * It can run in atomic context
 *
 * Return: 0 on success, -ETIMEDOUT on timeout
 */
static int ocores_process_polling(struct ocores_i2c *i2c)
{
	irqreturn_t ret;
	int err = 0;

	while (1) {
		err = ocores_poll_wait(i2c);
		if (err)
			break; /* timeout */

		ret = ocores_isr(-1, i2c);
		if (ret == IRQ_NONE)
			break; /* all messages have been transferred */
		else {
			if (i2c->flags & OCORES_FLAG_BROKEN_IRQ)
				if (i2c->state == STATE_DONE)
					break;
		}
	}

	return err;
}

static int ocores_xfer_core(struct ocores_i2c *i2c,
			    struct i2c_msg *msgs, int num,
			    bool polling)
{
	int ret = 0;
	u8 ctrl;

	ctrl = oc_getreg(i2c, OCI2C_CONTROL);
	if (polling)
		oc_setreg(i2c, OCI2C_CONTROL, ctrl & ~OCI2C_CTRL_IEN);
	else
		oc_setreg(i2c, OCI2C_CONTROL, ctrl | OCI2C_CTRL_IEN);

	i2c->msg = msgs;
	i2c->pos = 0;
	i2c->nmsgs = num;
	i2c->state = STATE_START;

	oc_setreg(i2c, OCI2C_DATA, i2c_8bit_addr_from_msg(i2c->msg));
	oc_setreg(i2c, OCI2C_CMD, OCI2C_CMD_START);

	if (polling) {
		ret = ocores_process_polling(i2c);
	} else {
		if (wait_event_timeout(i2c->wait,
				       (i2c->state == STATE_ERROR) ||
				       (i2c->state == STATE_DONE), HZ) == 0)
			ret = -ETIMEDOUT;
	}
	if (ret) {
		ocores_process_timeout(i2c);
		return ret;
	}

	return (i2c->state == STATE_DONE) ? num : -EIO;
}

static int ocores_xfer_polling(struct i2c_adapter *adap,
			       struct i2c_msg *msgs, int num)
{
	return ocores_xfer_core(i2c_get_adapdata(adap), msgs, num, true);
}

static int ocores_xfer(struct i2c_adapter *adap,
		       struct i2c_msg *msgs, int num)
{
	return ocores_xfer_core(i2c_get_adapdata(adap), msgs, num, false);
}

static int ocores_init(struct device *dev, struct ocores_i2c *i2c)
{
	int prescale;
	int diff;
	u8 ctrl = oc_getreg(i2c, OCI2C_CONTROL);

	/* make sure the device is disabled */
	ctrl &= ~(OCI2C_CTRL_EN | OCI2C_CTRL_IEN);
	oc_setreg(i2c, OCI2C_CONTROL, ctrl);

	prescale = (i2c->ip_clock_khz / (5 * i2c->bus_clock_khz)) - 1;
	prescale = clamp(prescale, 0, 0xffff);

	diff = i2c->ip_clock_khz / (5 * (prescale + 1)) - i2c->bus_clock_khz;
	if (abs(diff) > i2c->bus_clock_khz / 10) {
		dev_err(dev,
			"Unsupported clock settings: core: %d KHz, bus: %d KHz\n",
			i2c->ip_clock_khz, i2c->bus_clock_khz);
		return -EINVAL;
	}

	oc_setreg(i2c, OCI2C_PRELOW, prescale & 0xff);
	oc_setreg(i2c, OCI2C_PREHIGH, prescale >> 8);

	/* Init the device */
	oc_setreg(i2c, OCI2C_CMD, OCI2C_CMD_IACK);
	oc_setreg(i2c, OCI2C_CONTROL, ctrl | OCI2C_CTRL_EN);

	return 0;
}


static u32 ocores_func(struct i2c_adapter *adap)
{
	return I2C_FUNC_I2C | I2C_FUNC_SMBUS_EMUL;
}

static struct i2c_algorithm ocores_algorithm = {
	.master_xfer = ocores_xfer,
	.master_xfer_atomic = ocores_xfer_polling,
	.functionality = ocores_func,
};

static const struct i2c_adapter ocores_adapter = {
	.owner = THIS_MODULE,
	.name = "i2c-ocores",
	.class = I2C_CLASS_DEPRECATED,
	.algo = &ocores_algorithm,
};

static const struct of_device_id ocores_i2c_match[] = {
	{
		.compatible = "opencores,i2c-ocores",
		.data = (void *)TYPE_OCORES,
	},
	{
		.compatible = "aeroflexgaisler,i2cmst",
		.data = (void *)TYPE_GRLIB,
	},
	{
		.compatible = "sifive,fu540-c000-i2c",
	},
	{
		.compatible = "sifive,i2c0",
	},
	{},
};
MODULE_DEVICE_TABLE(of, ocores_i2c_match);

#ifdef CONFIG_OF
/*
 * Read and write functions for the GRLIB port of the controller. Registers are
 * 32-bit big endian and the PRELOW and PREHIGH registers are merged into one
 * register. The subsequent registers have their offsets decreased accordingly.
 */
static u8 oc_getreg_grlib(struct ocores_i2c *i2c, int reg)
{
	u32 rd;
	int rreg = reg;

	if (reg != OCI2C_PRELOW)
		rreg--;
	rd = ioread32be(i2c->base + (rreg << i2c->reg_shift));
	if (reg == OCI2C_PREHIGH)
		return (u8)(rd >> 8);
	else
		return (u8)rd;
}

static void oc_setreg_grlib(struct ocores_i2c *i2c, int reg, u8 value)
{
	u32 curr, wr;
	int rreg = reg;

	if (reg != OCI2C_PRELOW)
		rreg--;
	if (reg == OCI2C_PRELOW || reg == OCI2C_PREHIGH) {
		curr = ioread32be(i2c->base + (rreg << i2c->reg_shift));
		if (reg == OCI2C_PRELOW)
			wr = (curr & 0xff00) | value;
		else
			wr = (((u32)value) << 8) | (curr & 0xff);
	} else {
		wr = value;
	}
	iowrite32be(wr, i2c->base + (rreg << i2c->reg_shift));
}

static int ocores_i2c_of_probe(struct platform_device *pdev,
				struct ocores_i2c *i2c)
{
	struct device_node *np = pdev->dev.of_node;
	const struct of_device_id *match;
	u32 val;
	u32 clock_frequency;
	bool clock_frequency_present;

	if (of_property_read_u32(np, "reg-shift", &i2c->reg_shift)) {
		/* no 'reg-shift', check for deprecated 'regstep' */
		if (!of_property_read_u32(np, "regstep", &val)) {
			if (!is_power_of_2(val)) {
				dev_err(&pdev->dev, "invalid regstep %d\n",
					val);
				return -EINVAL;
			}
			i2c->reg_shift = ilog2(val);
			dev_warn(&pdev->dev,
				"regstep property deprecated, use reg-shift\n");
		}
	}

	clock_frequency_present = !of_property_read_u32(np, "clock-frequency",
							&clock_frequency);
	i2c->bus_clock_khz = 100;

	i2c->clk = devm_clk_get_optional_enabled(&pdev->dev, NULL);
	if (IS_ERR(i2c->clk))
		return dev_err_probe(&pdev->dev, PTR_ERR(i2c->clk),
				     "devm_clk_get_optional_enabled failed\n");

	i2c->ip_clock_khz = clk_get_rate(i2c->clk) / 1000;
	if (clock_frequency_present)
		i2c->bus_clock_khz = clock_frequency / 1000;
	if (i2c->ip_clock_khz == 0) {
		if (of_property_read_u32(np, "opencores,ip-clock-frequency",
						&val)) {
			if (!clock_frequency_present) {
				dev_err(&pdev->dev,
					"Missing required parameter 'opencores,ip-clock-frequency'\n");
				return -ENODEV;
			}
			i2c->ip_clock_khz = clock_frequency / 1000;
			dev_warn(&pdev->dev,
				 "Deprecated usage of the 'clock-frequency' property, please update to 'opencores,ip-clock-frequency'\n");
		} else {
			i2c->ip_clock_khz = val / 1000;
			if (clock_frequency_present)
				i2c->bus_clock_khz = clock_frequency / 1000;
		}
	}

	of_property_read_u32(pdev->dev.of_node, "reg-io-width",
				&i2c->reg_io_width);

	match = of_match_node(ocores_i2c_match, pdev->dev.of_node);
	if (match && (long)match->data == TYPE_GRLIB) {
		dev_dbg(&pdev->dev, "GRLIB variant of i2c-ocores\n");
		i2c->setreg = oc_setreg_grlib;
		i2c->getreg = oc_getreg_grlib;
	}

	return 0;
}
#else
#define ocores_i2c_of_probe(pdev, i2c) -ENODEV
#endif

static int ocores_i2c_probe(struct platform_device *pdev)
{
	struct ocores_i2c *i2c;
	struct ocores_i2c_platform_data *pdata;
	struct resource *res;
	int irq;
	int ret;
	int i;

	i2c = devm_kzalloc(&pdev->dev, sizeof(*i2c), GFP_KERNEL);
	if (!i2c)
		return -ENOMEM;

	spin_lock_init(&i2c->process_lock);

	res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
	if (res) {
		i2c->base = devm_ioremap_resource(&pdev->dev, res);
		if (IS_ERR(i2c->base))
			return PTR_ERR(i2c->base);
	} else {
		res = platform_get_resource(pdev, IORESOURCE_IO, 0);
		if (!res)
			return -EINVAL;
		i2c->iobase = res->start;
		if (!devm_request_region(&pdev->dev, res->start,
					 resource_size(res),
					 pdev->name)) {
			dev_err(&pdev->dev, "Can't get I/O resource.\n");
			return -EBUSY;
		}
		i2c->setreg = oc_setreg_io_8;
		i2c->getreg = oc_getreg_io_8;
	}

	pdata = dev_get_platdata(&pdev->dev);
	if (pdata) {
		i2c->reg_shift = pdata->reg_shift;
		i2c->reg_io_width = pdata->reg_io_width;
		i2c->ip_clock_khz = pdata->clock_khz;
		if (pdata->bus_khz)
			i2c->bus_clock_khz = pdata->bus_khz;
		else
			i2c->bus_clock_khz = 100;
	} else {
		ret = ocores_i2c_of_probe(pdev, i2c);
		if (ret)
			return ret;
	}

	if (i2c->reg_io_width == 0)
		i2c->reg_io_width = 1; /* Set to default value */

	if (!i2c->setreg || !i2c->getreg) {
		bool be = pdata ? pdata->big_endian :
			of_device_is_big_endian(pdev->dev.of_node);

		switch (i2c->reg_io_width) {
		case 1:
			i2c->setreg = oc_setreg_8;
			i2c->getreg = oc_getreg_8;
			break;

		case 2:
			i2c->setreg = be ? oc_setreg_16be : oc_setreg_16;
			i2c->getreg = be ? oc_getreg_16be : oc_getreg_16;
			break;

		case 4:
			i2c->setreg = be ? oc_setreg_32be : oc_setreg_32;
			i2c->getreg = be ? oc_getreg_32be : oc_getreg_32;
			break;

		default:
			dev_err(&pdev->dev, "Unsupported I/O width (%d)\n",
				i2c->reg_io_width);
			return -EINVAL;
		}
	}

	init_waitqueue_head(&i2c->wait);

	irq = platform_get_irq_optional(pdev, 0);
	/*
	 * Since the SoC does have an interrupt, its DT has an interrupt
	 * property - But this should be bypassed as the IRQ logic in this
	 * SoC is broken.
	 */
	if (of_device_is_compatible(pdev->dev.of_node,
				    "sifive,fu540-c000-i2c")) {
		i2c->flags |= OCORES_FLAG_BROKEN_IRQ;
		irq = -ENXIO;
	}

	if (irq == -ENXIO) {
		ocores_algorithm.master_xfer = ocores_xfer_polling;
	} else {
		if (irq < 0)
			return irq;
	}

	if (ocores_algorithm.master_xfer != ocores_xfer_polling) {
		ret = devm_request_any_context_irq(&pdev->dev, irq,
						   ocores_isr, 0,
						   pdev->name, i2c);
		if (ret) {
			dev_err(&pdev->dev, "Cannot claim IRQ\n");
			return ret;
		}
	}

	ret = ocores_init(&pdev->dev, i2c);
	if (ret)
		return ret;

	/* hook up driver to tree */
	platform_set_drvdata(pdev, i2c);
	i2c->adap = ocores_adapter;
	i2c_set_adapdata(&i2c->adap, i2c);
	i2c->adap.dev.parent = &pdev->dev;
	i2c->adap.dev.of_node = pdev->dev.of_node;

	/* add i2c adapter to i2c tree */
	ret = i2c_add_adapter(&i2c->adap);
	if (ret)
		return ret;

	/* add in known devices to the bus */
	if (pdata) {
		for (i = 0; i < pdata->num_devices; i++)
			i2c_new_client_device(&i2c->adap, pdata->devices + i);
	}

	return 0;
}

static void ocores_i2c_remove(struct platform_device *pdev)
{
	struct ocores_i2c *i2c = platform_get_drvdata(pdev);
	u8 ctrl = oc_getreg(i2c, OCI2C_CONTROL);

	/* disable i2c logic */
	ctrl &= ~(OCI2C_CTRL_EN | OCI2C_CTRL_IEN);
	oc_setreg(i2c, OCI2C_CONTROL, ctrl);

	/* remove adapter & data */
	i2c_del_adapter(&i2c->adap);
}

static int ocores_i2c_suspend(struct device *dev)
{
	struct ocores_i2c *i2c = dev_get_drvdata(dev);
	u8 ctrl = oc_getreg(i2c, OCI2C_CONTROL);

	/* make sure the device is disabled */
	ctrl &= ~(OCI2C_CTRL_EN | OCI2C_CTRL_IEN);
	oc_setreg(i2c, OCI2C_CONTROL, ctrl);

	clk_disable_unprepare(i2c->clk);
	return 0;
}

static int ocores_i2c_resume(struct device *dev)
{
	struct ocores_i2c *i2c = dev_get_drvdata(dev);
	unsigned long rate;
	int ret;

	ret = clk_prepare_enable(i2c->clk);
	if (ret)
		return dev_err_probe(dev, ret, "clk_prepare_enable failed\n");
	rate = clk_get_rate(i2c->clk) / 1000;
	if (rate)
		i2c->ip_clock_khz = rate;
	return ocores_init(dev, i2c);
}

static DEFINE_NOIRQ_DEV_PM_OPS(ocores_i2c_pm,
			       ocores_i2c_suspend, ocores_i2c_resume);

static struct platform_driver ocores_i2c_driver = {
	.probe   = ocores_i2c_probe,
	.remove_new = ocores_i2c_remove,
	.driver  = {
		.name = "ocores-i2c",
		.of_match_table = ocores_i2c_match,
		.pm = pm_sleep_ptr(&ocores_i2c_pm),
	},
};

module_platform_driver(ocores_i2c_driver);

MODULE_AUTHOR("Peter Korsgaard <peter@korsgaard.com>");
MODULE_DESCRIPTION("OpenCores I2C bus driver");
MODULE_LICENSE("GPL");
MODULE_ALIAS("platform:ocores-i2c");