aboutsummaryrefslogtreecommitdiff
path: root/drivers/i2c/busses/i2c-mpc.c
blob: e86cef300c7d694090a15df38cb627e4182d8c61 (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
/*
 * (C) Copyright 2003-2004
 * Humboldt Solutions Ltd, adrian@humboldt.co.uk.

 * This is a combined i2c adapter and algorithm driver for the
 * MPC107/Tsi107 PowerPC northbridge and processors that include
 * the same I2C unit (8240, 8245, 85xx).
 *
 * Release 0.8
 *
 * 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/module.h>
#include <linux/sched.h>
#include <linux/init.h>
#include <linux/of_platform.h>
#include <linux/of_i2c.h>
#include <linux/slab.h>

#include <linux/io.h>
#include <linux/fsl_devices.h>
#include <linux/i2c.h>
#include <linux/interrupt.h>
#include <linux/delay.h>

#include <asm/mpc52xx.h>
#include <sysdev/fsl_soc.h>

#define DRV_NAME "mpc-i2c"

#define MPC_I2C_CLOCK_LEGACY   0
#define MPC_I2C_CLOCK_PRESERVE (~0U)

#define MPC_I2C_FDR   0x04
#define MPC_I2C_CR    0x08
#define MPC_I2C_SR    0x0c
#define MPC_I2C_DR    0x10
#define MPC_I2C_DFSRR 0x14

#define CCR_MEN  0x80
#define CCR_MIEN 0x40
#define CCR_MSTA 0x20
#define CCR_MTX  0x10
#define CCR_TXAK 0x08
#define CCR_RSTA 0x04

#define CSR_MCF  0x80
#define CSR_MAAS 0x40
#define CSR_MBB  0x20
#define CSR_MAL  0x10
#define CSR_SRW  0x04
#define CSR_MIF  0x02
#define CSR_RXAK 0x01

struct mpc_i2c {
	struct device *dev;
	void __iomem *base;
	u32 interrupt;
	wait_queue_head_t queue;
	struct i2c_adapter adap;
	int irq;
};

struct mpc_i2c_divider {
	u16 divider;
	u16 fdr;	/* including dfsrr */
};

struct mpc_i2c_data {
	void (*setup)(struct device_node *node, struct mpc_i2c *i2c,
		      u32 clock, u32 prescaler);
	u32 prescaler;
};

static inline void writeccr(struct mpc_i2c *i2c, u32 x)
{
	writeb(x, i2c->base + MPC_I2C_CR);
}

static irqreturn_t mpc_i2c_isr(int irq, void *dev_id)
{
	struct mpc_i2c *i2c = dev_id;
	if (readb(i2c->base + MPC_I2C_SR) & CSR_MIF) {
		/* Read again to allow register to stabilise */
		i2c->interrupt = readb(i2c->base + MPC_I2C_SR);
		writeb(0, i2c->base + MPC_I2C_SR);
		wake_up(&i2c->queue);
	}
	return IRQ_HANDLED;
}

/* Sometimes 9th clock pulse isn't generated, and slave doesn't release
 * the bus, because it wants to send ACK.
 * Following sequence of enabling/disabling and sending start/stop generates
 * the pulse, so it's all OK.
 */
static void mpc_i2c_fixup(struct mpc_i2c *i2c)
{
	writeccr(i2c, 0);
	udelay(30);
	writeccr(i2c, CCR_MEN);
	udelay(30);
	writeccr(i2c, CCR_MSTA | CCR_MTX);
	udelay(30);
	writeccr(i2c, CCR_MSTA | CCR_MTX | CCR_MEN);
	udelay(30);
	writeccr(i2c, CCR_MEN);
	udelay(30);
}

static int i2c_wait(struct mpc_i2c *i2c, unsigned timeout, int writing)
{
	unsigned long orig_jiffies = jiffies;
	u32 x;
	int result = 0;

	if (!i2c->irq) {
		while (!(readb(i2c->base + MPC_I2C_SR) & CSR_MIF)) {
			schedule();
			if (time_after(jiffies, orig_jiffies + timeout)) {
				dev_dbg(i2c->dev, "timeout\n");
				writeccr(i2c, 0);
				result = -EIO;
				break;
			}
		}
		x = readb(i2c->base + MPC_I2C_SR);
		writeb(0, i2c->base + MPC_I2C_SR);
	} else {
		/* Interrupt mode */
		result = wait_event_timeout(i2c->queue,
			(i2c->interrupt & CSR_MIF), timeout);

		if (unlikely(!(i2c->interrupt & CSR_MIF))) {
			dev_dbg(i2c->dev, "wait timeout\n");
			writeccr(i2c, 0);
			result = -ETIMEDOUT;
		}

		x = i2c->interrupt;
		i2c->interrupt = 0;
	}

	if (result < 0)
		return result;

	if (!(x & CSR_MCF)) {
		dev_dbg(i2c->dev, "unfinished\n");
		return -EIO;
	}

	if (x & CSR_MAL) {
		dev_dbg(i2c->dev, "MAL\n");
		return -EIO;
	}

	if (writing && (x & CSR_RXAK)) {
		dev_dbg(i2c->dev, "No RXAK\n");
		/* generate stop */
		writeccr(i2c, CCR_MEN);
		return -EIO;
	}
	return 0;
}

#if defined(CONFIG_PPC_MPC52xx) || defined(CONFIG_PPC_MPC512x)
static const struct mpc_i2c_divider mpc_i2c_dividers_52xx[] __devinitconst = {
	{20, 0x20}, {22, 0x21}, {24, 0x22}, {26, 0x23},
	{28, 0x24}, {30, 0x01}, {32, 0x25}, {34, 0x02},
	{36, 0x26}, {40, 0x27}, {44, 0x04}, {48, 0x28},
	{52, 0x63}, {56, 0x29}, {60, 0x41}, {64, 0x2a},
	{68, 0x07}, {72, 0x2b}, {80, 0x2c}, {88, 0x09},
	{96, 0x2d}, {104, 0x0a}, {112, 0x2e}, {120, 0x81},
	{128, 0x2f}, {136, 0x47}, {144, 0x0c}, {160, 0x30},
	{176, 0x49}, {192, 0x31}, {208, 0x4a}, {224, 0x32},
	{240, 0x0f}, {256, 0x33}, {272, 0x87}, {288, 0x10},
	{320, 0x34}, {352, 0x89}, {384, 0x35}, {416, 0x8a},
	{448, 0x36}, {480, 0x13}, {512, 0x37}, {576, 0x14},
	{640, 0x38}, {768, 0x39}, {896, 0x3a}, {960, 0x17},
	{1024, 0x3b}, {1152, 0x18}, {1280, 0x3c}, {1536, 0x3d},
	{1792, 0x3e}, {1920, 0x1b}, {2048, 0x3f}, {2304, 0x1c},
	{2560, 0x1d}, {3072, 0x1e}, {3584, 0x7e}, {3840, 0x1f},
	{4096, 0x7f}, {4608, 0x5c}, {5120, 0x5d}, {6144, 0x5e},
	{7168, 0xbe}, {7680, 0x5f}, {8192, 0xbf}, {9216, 0x9c},
	{10240, 0x9d}, {12288, 0x9e}, {15360, 0x9f}
};

static int __devinit mpc_i2c_get_fdr_52xx(struct device_node *node, u32 clock,
					  int prescaler)
{
	const struct mpc_i2c_divider *div = NULL;
	unsigned int pvr = mfspr(SPRN_PVR);
	u32 divider;
	int i;

	if (clock == MPC_I2C_CLOCK_LEGACY)
		return -EINVAL;

	/* Determine divider value */
	divider = mpc5xxx_get_bus_frequency(node) / clock;

	/*
	 * We want to choose an FDR/DFSR that generates an I2C bus speed that
	 * is equal to or lower than the requested speed.
	 */
	for (i = 0; i < ARRAY_SIZE(mpc_i2c_dividers_52xx); i++) {
		div = &mpc_i2c_dividers_52xx[i];
		/* Old MPC5200 rev A CPUs do not support the high bits */
		if (div->fdr & 0xc0 && pvr == 0x80822011)
			continue;
		if (div->divider >= divider)
			break;
	}

	return div ? (int)div->fdr : -EINVAL;
}

static void __devinit mpc_i2c_setup_52xx(struct device_node *node,
					 struct mpc_i2c *i2c,
					 u32 clock, u32 prescaler)
{
	int ret, fdr;

	if (clock == MPC_I2C_CLOCK_PRESERVE) {
		dev_dbg(i2c->dev, "using fdr %d\n",
			readb(i2c->base + MPC_I2C_FDR));
		return;
	}

	ret = mpc_i2c_get_fdr_52xx(node, clock, prescaler);
	fdr = (ret >= 0) ? ret : 0x3f; /* backward compatibility */

	writeb(fdr & 0xff, i2c->base + MPC_I2C_FDR);

	if (ret >= 0)
		dev_info(i2c->dev, "clock %d Hz (fdr=%d)\n", clock, fdr);
}
#else /* !(CONFIG_PPC_MPC52xx || CONFIG_PPC_MPC512x) */
static void __devinit mpc_i2c_setup_52xx(struct device_node *node,
					 struct mpc_i2c *i2c,
					 u32 clock, u32 prescaler)
{
}
#endif /* CONFIG_PPC_MPC52xx || CONFIG_PPC_MPC512x */

#ifdef CONFIG_PPC_MPC512x
static void __devinit mpc_i2c_setup_512x(struct device_node *node,
					 struct mpc_i2c *i2c,
					 u32 clock, u32 prescaler)
{
	struct device_node *node_ctrl;
	void __iomem *ctrl;
	const u32 *pval;
	u32 idx;

	/* Enable I2C interrupts for mpc5121 */
	node_ctrl = of_find_compatible_node(NULL, NULL,
					    "fsl,mpc5121-i2c-ctrl");
	if (node_ctrl) {
		ctrl = of_iomap(node_ctrl, 0);
		if (ctrl) {
			/* Interrupt enable bits for i2c-0/1/2: bit 24/26/28 */
			pval = of_get_property(node, "reg", NULL);
			idx = (*pval & 0xff) / 0x20;
			setbits32(ctrl, 1 << (24 + idx * 2));
			iounmap(ctrl);
		}
		of_node_put(node_ctrl);
	}

	/* The clock setup for the 52xx works also fine for the 512x */
	mpc_i2c_setup_52xx(node, i2c, clock, prescaler);
}
#else /* CONFIG_PPC_MPC512x */
static void __devinit mpc_i2c_setup_512x(struct device_node *node,
					 struct mpc_i2c *i2c,
					 u32 clock, u32 prescaler)
{
}
#endif /* CONFIG_PPC_MPC512x */

#ifdef CONFIG_FSL_SOC
static const struct mpc_i2c_divider mpc_i2c_dividers_8xxx[] __devinitconst = {
	{160, 0x0120}, {192, 0x0121}, {224, 0x0122}, {256, 0x0123},
	{288, 0x0100}, {320, 0x0101}, {352, 0x0601}, {384, 0x0102},
	{416, 0x0602}, {448, 0x0126}, {480, 0x0103}, {512, 0x0127},
	{544, 0x0b03}, {576, 0x0104}, {608, 0x1603}, {640, 0x0105},
	{672, 0x2003}, {704, 0x0b05}, {736, 0x2b03}, {768, 0x0106},
	{800, 0x3603}, {832, 0x0b06}, {896, 0x012a}, {960, 0x0107},
	{1024, 0x012b}, {1088, 0x1607}, {1152, 0x0108}, {1216, 0x2b07},
	{1280, 0x0109}, {1408, 0x1609}, {1536, 0x010a}, {1664, 0x160a},
	{1792, 0x012e}, {1920, 0x010b}, {2048, 0x012f}, {2176, 0x2b0b},
	{2304, 0x010c}, {2560, 0x010d}, {2816, 0x2b0d}, {3072, 0x010e},
	{3328, 0x2b0e}, {3584, 0x0132}, {3840, 0x010f}, {4096, 0x0133},
	{4608, 0x0110}, {5120, 0x0111}, {6144, 0x0112}, {7168, 0x0136},
	{7680, 0x0113}, {8192, 0x0137}, {9216, 0x0114}, {10240, 0x0115},
	{12288, 0x0116}, {14336, 0x013a}, {15360, 0x0117}, {16384, 0x013b},
	{18432, 0x0118}, {20480, 0x0119}, {24576, 0x011a}, {28672, 0x013e},
	{30720, 0x011b}, {32768, 0x013f}, {36864, 0x011c}, {40960, 0x011d},
	{49152, 0x011e}, {61440, 0x011f}
};

static u32 __devinit mpc_i2c_get_sec_cfg_8xxx(void)
{
	struct device_node *node = NULL;
	u32 __iomem *reg;
	u32 val = 0;

	node = of_find_node_by_name(NULL, "global-utilities");
	if (node) {
		const u32 *prop = of_get_property(node, "reg", NULL);
		if (prop) {
			/*
			 * Map and check POR Device Status Register 2
			 * (PORDEVSR2) at 0xE0014
			 */
			reg = ioremap(get_immrbase() + *prop + 0x14, 0x4);
			if (!reg)
				printk(KERN_ERR
				       "Error: couldn't map PORDEVSR2\n");
			else
				val = in_be32(reg) & 0x00000080; /* sec-cfg */
			iounmap(reg);
		}
	}
	if (node)
		of_node_put(node);

	return val;
}

static int __devinit mpc_i2c_get_fdr_8xxx(struct device_node *node, u32 clock,
					  u32 prescaler)
{
	const struct mpc_i2c_divider *div = NULL;
	u32 divider;
	int i;

	if (clock == MPC_I2C_CLOCK_LEGACY)
		return -EINVAL;

	/* Determine proper divider value */
	if (of_device_is_compatible(node, "fsl,mpc8544-i2c"))
		prescaler = mpc_i2c_get_sec_cfg_8xxx() ? 3 : 2;
	if (!prescaler)
		prescaler = 1;

	divider = fsl_get_sys_freq() / clock / prescaler;

	pr_debug("I2C: src_clock=%d clock=%d divider=%d\n",
		 fsl_get_sys_freq(), clock, divider);

	/*
	 * We want to choose an FDR/DFSR that generates an I2C bus speed that
	 * is equal to or lower than the requested speed.
	 */
	for (i = 0; i < ARRAY_SIZE(mpc_i2c_dividers_8xxx); i++) {
		div = &mpc_i2c_dividers_8xxx[i];
		if (div->divider >= divider)
			break;
	}

	return div ? (int)div->fdr : -EINVAL;
}

static void __devinit mpc_i2c_setup_8xxx(struct device_node *node,
					 struct mpc_i2c *i2c,
					 u32 clock, u32 prescaler)
{
	int ret, fdr;

	if (clock == MPC_I2C_CLOCK_PRESERVE) {
		dev_dbg(i2c->dev, "using dfsrr %d, fdr %d\n",
			readb(i2c->base + MPC_I2C_DFSRR),
			readb(i2c->base + MPC_I2C_FDR));
		return;
	}

	ret = mpc_i2c_get_fdr_8xxx(node, clock, prescaler);
	fdr = (ret >= 0) ? ret : 0x1031; /* backward compatibility */

	writeb(fdr & 0xff, i2c->base + MPC_I2C_FDR);
	writeb((fdr >> 8) & 0xff, i2c->base + MPC_I2C_DFSRR);

	if (ret >= 0)
		dev_info(i2c->dev, "clock %d Hz (dfsrr=%d fdr=%d)\n",
			 clock, fdr >> 8, fdr & 0xff);
}

#else /* !CONFIG_FSL_SOC */
static void __devinit mpc_i2c_setup_8xxx(struct device_node *node,
					 struct mpc_i2c *i2c,
					 u32 clock, u32 prescaler)
{
}
#endif /* CONFIG_FSL_SOC */

static void mpc_i2c_start(struct mpc_i2c *i2c)
{
	/* Clear arbitration */
	writeb(0, i2c->base + MPC_I2C_SR);
	/* Start with MEN */
	writeccr(i2c, CCR_MEN);
}

static void mpc_i2c_stop(struct mpc_i2c *i2c)
{
	writeccr(i2c, CCR_MEN);
}

static int mpc_write(struct mpc_i2c *i2c, int target,
		     const u8 *data, int length, int restart)
{
	int i, result;
	unsigned timeout = i2c->adap.timeout;
	u32 flags = restart ? CCR_RSTA : 0;

	/* Start as master */
	writeccr(i2c, CCR_MIEN | CCR_MEN | CCR_MSTA | CCR_MTX | flags);
	/* Write target byte */
	writeb((target << 1), i2c->base + MPC_I2C_DR);

	result = i2c_wait(i2c, timeout, 1);
	if (result < 0)
		return result;

	for (i = 0; i < length; i++) {
		/* Write data byte */
		writeb(data[i], i2c->base + MPC_I2C_DR);

		result = i2c_wait(i2c, timeout, 1);
		if (result < 0)
			return result;
	}

	return 0;
}

static int mpc_read(struct mpc_i2c *i2c, int target,
		    u8 *data, int length, int restart)
{
	unsigned timeout = i2c->adap.timeout;
	int i, result;
	u32 flags = restart ? CCR_RSTA : 0;

	/* Switch to read - restart */
	writeccr(i2c, CCR_MIEN | CCR_MEN | CCR_MSTA | CCR_MTX | flags);
	/* Write target address byte - this time with the read flag set */
	writeb((target << 1) | 1, i2c->base + MPC_I2C_DR);

	result = i2c_wait(i2c, timeout, 1);
	if (result < 0)
		return result;

	if (length) {
		if (length == 1)
			writeccr(i2c, CCR_MIEN | CCR_MEN | CCR_MSTA | CCR_TXAK);
		else
			writeccr(i2c, CCR_MIEN | CCR_MEN | CCR_MSTA);
		/* Dummy read */
		readb(i2c->base + MPC_I2C_DR);
	}

	for (i = 0; i < length; i++) {
		result = i2c_wait(i2c, timeout, 0);
		if (result < 0)
			return result;

		/* Generate txack on next to last byte */
		if (i == length - 2)
			writeccr(i2c, CCR_MIEN | CCR_MEN | CCR_MSTA | CCR_TXAK);
		/* Do not generate stop on last byte */
		if (i == length - 1)
			writeccr(i2c, CCR_MIEN | CCR_MEN | CCR_MSTA | CCR_MTX);
		data[i] = readb(i2c->base + MPC_I2C_DR);
	}

	return length;
}

static int mpc_xfer(struct i2c_adapter *adap, struct i2c_msg *msgs, int num)
{
	struct i2c_msg *pmsg;
	int i;
	int ret = 0;
	unsigned long orig_jiffies = jiffies;
	struct mpc_i2c *i2c = i2c_get_adapdata(adap);

	mpc_i2c_start(i2c);

	/* Allow bus up to 1s to become not busy */
	while (readb(i2c->base + MPC_I2C_SR) & CSR_MBB) {
		if (signal_pending(current)) {
			dev_dbg(i2c->dev, "Interrupted\n");
			writeccr(i2c, 0);
			return -EINTR;
		}
		if (time_after(jiffies, orig_jiffies + HZ)) {
			dev_dbg(i2c->dev, "timeout\n");
			if (readb(i2c->base + MPC_I2C_SR) ==
			    (CSR_MCF | CSR_MBB | CSR_RXAK))
				mpc_i2c_fixup(i2c);
			return -EIO;
		}
		schedule();
	}

	for (i = 0; ret >= 0 && i < num; i++) {
		pmsg = &msgs[i];
		dev_dbg(i2c->dev,
			"Doing %s %d bytes to 0x%02x - %d of %d messages\n",
			pmsg->flags & I2C_M_RD ? "read" : "write",
			pmsg->len, pmsg->addr, i + 1, num);
		if (pmsg->flags & I2C_M_RD)
			ret =
			    mpc_read(i2c, pmsg->addr, pmsg->buf, pmsg->len, i);
		else
			ret =
			    mpc_write(i2c, pmsg->addr, pmsg->buf, pmsg->len, i);
	}
	mpc_i2c_stop(i2c);
	return (ret < 0) ? ret : num;
}

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

static const struct i2c_algorithm mpc_algo = {
	.master_xfer = mpc_xfer,
	.functionality = mpc_functionality,
};

static struct i2c_adapter mpc_ops = {
	.owner = THIS_MODULE,
	.name = "MPC adapter",
	.algo = &mpc_algo,
	.timeout = HZ,
};

static int __devinit fsl_i2c_probe(struct of_device *op,
				   const struct of_device_id *match)
{
	struct mpc_i2c *i2c;
	const u32 *prop;
	u32 clock = MPC_I2C_CLOCK_LEGACY;
	int result = 0;
	int plen;

	i2c = kzalloc(sizeof(*i2c), GFP_KERNEL);
	if (!i2c)
		return -ENOMEM;

	i2c->dev = &op->dev; /* for debug and error output */

	init_waitqueue_head(&i2c->queue);

	i2c->base = of_iomap(op->node, 0);
	if (!i2c->base) {
		dev_err(i2c->dev, "failed to map controller\n");
		result = -ENOMEM;
		goto fail_map;
	}

	i2c->irq = irq_of_parse_and_map(op->node, 0);
	if (i2c->irq) { /* no i2c->irq implies polling */
		result = request_irq(i2c->irq, mpc_i2c_isr,
				     IRQF_SHARED, "i2c-mpc", i2c);
		if (result < 0) {
			dev_err(i2c->dev, "failed to attach interrupt\n");
			goto fail_request;
		}
	}

	if (of_get_property(op->node, "fsl,preserve-clocking", NULL)) {
		clock = MPC_I2C_CLOCK_PRESERVE;
	} else {
		prop = of_get_property(op->node, "clock-frequency", &plen);
		if (prop && plen == sizeof(u32))
			clock = *prop;
	}

	if (match->data) {
		struct mpc_i2c_data *data = match->data;
		data->setup(op->node, i2c, clock, data->prescaler);
	} else {
		/* Backwards compatibility */
		if (of_get_property(op->node, "dfsrr", NULL))
			mpc_i2c_setup_8xxx(op->node, i2c, clock, 0);
	}

	dev_set_drvdata(&op->dev, i2c);

	i2c->adap = mpc_ops;
	i2c_set_adapdata(&i2c->adap, i2c);
	i2c->adap.dev.parent = &op->dev;

	result = i2c_add_adapter(&i2c->adap);
	if (result < 0) {
		dev_err(i2c->dev, "failed to add adapter\n");
		goto fail_add;
	}
	of_register_i2c_devices(&i2c->adap, op->node);

	return result;

 fail_add:
	dev_set_drvdata(&op->dev, NULL);
	free_irq(i2c->irq, i2c);
 fail_request:
	irq_dispose_mapping(i2c->irq);
	iounmap(i2c->base);
 fail_map:
	kfree(i2c);
	return result;
};

static int __devexit fsl_i2c_remove(struct of_device *op)
{
	struct mpc_i2c *i2c = dev_get_drvdata(&op->dev);

	i2c_del_adapter(&i2c->adap);
	dev_set_drvdata(&op->dev, NULL);

	if (i2c->irq)
		free_irq(i2c->irq, i2c);

	irq_dispose_mapping(i2c->irq);
	iounmap(i2c->base);
	kfree(i2c);
	return 0;
};

static struct mpc_i2c_data mpc_i2c_data_512x __devinitdata = {
	.setup = mpc_i2c_setup_512x,
};

static struct mpc_i2c_data mpc_i2c_data_52xx __devinitdata = {
	.setup = mpc_i2c_setup_52xx,
};

static struct mpc_i2c_data mpc_i2c_data_8313 __devinitdata = {
	.setup = mpc_i2c_setup_8xxx,
};

static struct mpc_i2c_data mpc_i2c_data_8543 __devinitdata = {
	.setup = mpc_i2c_setup_8xxx,
	.prescaler = 2,
};

static struct mpc_i2c_data mpc_i2c_data_8544 __devinitdata = {
	.setup = mpc_i2c_setup_8xxx,
	.prescaler = 3,
};

static const struct of_device_id mpc_i2c_of_match[] = {
	{.compatible = "mpc5200-i2c", .data = &mpc_i2c_data_52xx, },
	{.compatible = "fsl,mpc5200b-i2c", .data = &mpc_i2c_data_52xx, },
	{.compatible = "fsl,mpc5200-i2c", .data = &mpc_i2c_data_52xx, },
	{.compatible = "fsl,mpc5121-i2c", .data = &mpc_i2c_data_512x, },
	{.compatible = "fsl,mpc8313-i2c", .data = &mpc_i2c_data_8313, },
	{.compatible = "fsl,mpc8543-i2c", .data = &mpc_i2c_data_8543, },
	{.compatible = "fsl,mpc8544-i2c", .data = &mpc_i2c_data_8544, },
	/* Backward compatibility */
	{.compatible = "fsl-i2c", },
	{},
};
MODULE_DEVICE_TABLE(of, mpc_i2c_of_match);

/* Structure for a device driver */
static struct of_platform_driver mpc_i2c_driver = {
	.match_table	= mpc_i2c_of_match,
	.probe		= fsl_i2c_probe,
	.remove		= __devexit_p(fsl_i2c_remove),
	.driver		= {
		.owner	= THIS_MODULE,
		.name	= DRV_NAME,
	},
};

static int __init fsl_i2c_init(void)
{
	int rv;

	rv = of_register_platform_driver(&mpc_i2c_driver);
	if (rv)
		printk(KERN_ERR DRV_NAME
		       " of_register_platform_driver failed (%i)\n", rv);
	return rv;
}

static void __exit fsl_i2c_exit(void)
{
	of_unregister_platform_driver(&mpc_i2c_driver);
}

module_init(fsl_i2c_init);
module_exit(fsl_i2c_exit);

MODULE_AUTHOR("Adrian Cox <adrian@humboldt.co.uk>");
MODULE_DESCRIPTION("I2C-Bus adapter for MPC107 bridge and "
		   "MPC824x/83xx/85xx/86xx/512x/52xx processors");
MODULE_LICENSE("GPL");