aboutsummaryrefslogtreecommitdiffstats
path: root/target/linux/brcm2708/patches-4.19/950-0052-Add-Chris-Boot-s-i2c-driver.patch
blob: cf26302f7106955f12fa3541dc3a653ce8eaa597 (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
From 1f72dfe2738305c57605a8192176117e1641779c Mon Sep 17 00:00:00 2001
From: popcornmix <popcornmix@gmail.com>
Date: Wed, 17 Jun 2015 15:44:08 +0100
Subject: [PATCH] Add Chris Boot's i2c driver
MIME-Version: 1.0
Content-Type: text/plain; charset=UTF-8
Content-Transfer-Encoding: 8bit

i2c-bcm2708: fixed baudrate

Fixed issue where the wrong CDIV value was set for baudrates below 3815 Hz (for 250MHz bus clock).
In that case the computed CDIV value was more than 0xffff. However the CDIV register width is only 16 bits.
This resulted in incorrect setting of CDIV and higher baudrate than intended.
Example: 3500Hz -> CDIV=0x11704 -> CDIV(16bit)=0x1704 -> 42430Hz
After correction: 3500Hz -> CDIV=0x11704 -> CDIV(16bit)=0xffff -> 3815Hz
The correct baudrate is shown in the log after the cdiv > 0xffff correction.

Perform I2C combined transactions when possible

Perform I2C combined transactions whenever possible, within the
restrictions of the Broadcomm Serial Controller.

Disable DONE interrupt during TA poll

Prevent interrupt from being triggered if poll is missed and transfer
starts and finishes.

i2c: Make combined transactions optional and disabled by default

i2c: bcm2708: add device tree support

Add DT support to driver and add to .dtsi file.
Setup pins in .dts file.
i2c is disabled by default.

Signed-off-by: Noralf Tronnes <notro@tronnes.org>

bcm2708: don't register i2c controllers when using DT

The devices for the i2c controllers are in the Device Tree.
Only register devices when not using DT.

Signed-off-by: Noralf Tronnes <notro@tronnes.org>

I2C: Only register the I2C device for the current board revision

i2c_bcm2708: Fix clock reference counting

Fix grabbing lock from atomic context in i2c driver

2 main changes:
- check for timeouts in the bcm2708_bsc_setup function as indicated by this comment:
      /* poll for transfer start bit (should only take 1-20 polls) */
  This implies that the setup function can now fail so account for this everywhere it's called
- Removed the clk_get_rate call from inside the setup function as it locks a mutex and that's not ok since we call it from under a spin lock.

i2c-bcm2708: When using DT, leave the GPIO setup to pinctrl

i2c-bcm2708: Increase timeouts to allow larger transfers

Use the timeout value provided by the I2C_TIMEOUT ioctl when waiting
for completion. The default timeout is 1 second.

See: https://github.com/raspberrypi/linux/issues/260

i2c-bcm2708/BCM270X_DT: Add support for I2C2

The third I2C bus (I2C2) is normally reserved for HDMI use. Careless
use of this bus can break an attached display - use with caution.

It is recommended to disable accesses by VideoCore by setting
hdmi_ignore_edid=1 or hdmi_edid_file=1 in config.txt.

The interface is disabled by default - enable using the
i2c2_iknowwhatimdoing DT parameter.

bcm2708-spi: Don't use static pin configuration with DT

Also remove superfluous error checking - the SPI framework ensures the
validity of the chip_select value.

i2c-bcm2708: Remove non-DT support

Signed-off-by: Noralf Trønnes <noralf@tronnes.org>

Set the BSC_CLKT clock streching timeout to 35ms as per SMBus specs.

Fixes i2c_bcm2708: Write to FIFO correctly - v2 (#1574)

* i2c: fix i2c_bcm2708: Clear FIFO before sending data

Make sure FIFO gets cleared before trying to send
data in case of a repeated start (COMBINED=Y).

* i2c: fix i2c_bcm2708: Only write to FIFO when not full

Check if FIFO can accept data before writing.
To avoid a peripheral read on the last iteration of a loop,
both bcm2708_bsc_fifo_fill and ~drain are changed as well.
---
 drivers/i2c/busses/Kconfig       |  19 ++
 drivers/i2c/busses/Makefile      |   2 +
 drivers/i2c/busses/i2c-bcm2708.c | 512 +++++++++++++++++++++++++++++++
 3 files changed, 533 insertions(+)
 create mode 100644 drivers/i2c/busses/i2c-bcm2708.c

--- a/drivers/i2c/busses/Kconfig
+++ b/drivers/i2c/busses/Kconfig
@@ -8,6 +8,25 @@ menu "I2C Hardware Bus support"
 comment "PC SMBus host controller drivers"
 	depends on PCI
 
+config I2C_BCM2708
+	tristate "BCM2708 BSC"
+	depends on ARCH_BCM2835
+	help
+	  Enabling this option will add BSC (Broadcom Serial Controller)
+	  support for the BCM2708. BSC is a Broadcom proprietary bus compatible
+	  with I2C/TWI/SMBus.
+
+config I2C_BCM2708_BAUDRATE
+	prompt "BCM2708 I2C baudrate"
+	depends on I2C_BCM2708
+	int
+	default 100000
+	help
+	  Set the I2C baudrate. This will alter the default value. A
+	  different baudrate can be set by using a module parameter as well. If
+	  no parameter is provided when loading, this is the value that will be
+	  used.
+
 config I2C_ALI1535
 	tristate "ALI 1535"
 	depends on PCI
--- a/drivers/i2c/busses/Makefile
+++ b/drivers/i2c/busses/Makefile
@@ -3,6 +3,8 @@
 # Makefile for the i2c bus drivers.
 #
 
+obj-$(CONFIG_I2C_BCM2708)	+= i2c-bcm2708.o
+
 # ACPI drivers
 obj-$(CONFIG_I2C_SCMI)		+= i2c-scmi.o
 
--- /dev/null
+++ b/drivers/i2c/busses/i2c-bcm2708.c
@@ -0,0 +1,512 @@
+/*
+ * Driver for Broadcom BCM2708 BSC Controllers
+ *
+ * Copyright (C) 2012 Chris Boot & Frank Buss
+ *
+ * This driver is inspired by:
+ * i2c-ocores.c, by Peter Korsgaard <jacmet@sunsite.dk>
+ *
+ * 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., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA.
+ */
+
+#include <linux/kernel.h>
+#include <linux/module.h>
+#include <linux/spinlock.h>
+#include <linux/clk.h>
+#include <linux/err.h>
+#include <linux/of.h>
+#include <linux/platform_device.h>
+#include <linux/io.h>
+#include <linux/slab.h>
+#include <linux/i2c.h>
+#include <linux/interrupt.h>
+#include <linux/sched.h>
+#include <linux/wait.h>
+
+/* BSC register offsets */
+#define BSC_C			0x00
+#define BSC_S			0x04
+#define BSC_DLEN		0x08
+#define BSC_A			0x0c
+#define BSC_FIFO		0x10
+#define BSC_DIV			0x14
+#define BSC_DEL			0x18
+#define BSC_CLKT		0x1c
+
+/* Bitfields in BSC_C */
+#define BSC_C_I2CEN		0x00008000
+#define BSC_C_INTR		0x00000400
+#define BSC_C_INTT		0x00000200
+#define BSC_C_INTD		0x00000100
+#define BSC_C_ST		0x00000080
+#define BSC_C_CLEAR_1		0x00000020
+#define BSC_C_CLEAR_2		0x00000010
+#define BSC_C_READ		0x00000001
+
+/* Bitfields in BSC_S */
+#define BSC_S_CLKT		0x00000200
+#define BSC_S_ERR		0x00000100
+#define BSC_S_RXF		0x00000080
+#define BSC_S_TXE		0x00000040
+#define BSC_S_RXD		0x00000020
+#define BSC_S_TXD		0x00000010
+#define BSC_S_RXR		0x00000008
+#define BSC_S_TXW		0x00000004
+#define BSC_S_DONE		0x00000002
+#define BSC_S_TA		0x00000001
+
+#define I2C_WAIT_LOOP_COUNT	200
+
+#define DRV_NAME		"bcm2708_i2c"
+
+static unsigned int baudrate;
+module_param(baudrate, uint, S_IRUSR | S_IWUSR | S_IRGRP | S_IWGRP);
+MODULE_PARM_DESC(baudrate, "The I2C baudrate");
+
+static bool combined = false;
+module_param(combined, bool, 0644);
+MODULE_PARM_DESC(combined, "Use combined transactions");
+
+struct bcm2708_i2c {
+	struct i2c_adapter adapter;
+
+	spinlock_t lock;
+	void __iomem *base;
+	int irq;
+	struct clk *clk;
+	u32 cdiv;
+	u32 clk_tout;
+
+	struct completion done;
+
+	struct i2c_msg *msg;
+	int pos;
+	int nmsgs;
+	bool error;
+};
+
+static inline u32 bcm2708_rd(struct bcm2708_i2c *bi, unsigned reg)
+{
+	return readl(bi->base + reg);
+}
+
+static inline void bcm2708_wr(struct bcm2708_i2c *bi, unsigned reg, u32 val)
+{
+	writel(val, bi->base + reg);
+}
+
+static inline void bcm2708_bsc_reset(struct bcm2708_i2c *bi)
+{
+	bcm2708_wr(bi, BSC_C, 0);
+	bcm2708_wr(bi, BSC_S, BSC_S_CLKT | BSC_S_ERR | BSC_S_DONE);
+}
+
+static inline void bcm2708_bsc_fifo_drain(struct bcm2708_i2c *bi)
+{
+	while ((bi->pos < bi->msg->len) && (bcm2708_rd(bi, BSC_S) & BSC_S_RXD))
+		bi->msg->buf[bi->pos++] = bcm2708_rd(bi, BSC_FIFO);
+}
+
+static inline void bcm2708_bsc_fifo_fill(struct bcm2708_i2c *bi)
+{
+	while ((bi->pos < bi->msg->len) && (bcm2708_rd(bi, BSC_S) & BSC_S_TXD))
+		bcm2708_wr(bi, BSC_FIFO, bi->msg->buf[bi->pos++]);
+}
+
+static inline int bcm2708_bsc_setup(struct bcm2708_i2c *bi)
+{
+	u32 cdiv, s, clk_tout;
+	u32 c = BSC_C_I2CEN | BSC_C_INTD | BSC_C_ST | BSC_C_CLEAR_1;
+	int wait_loops = I2C_WAIT_LOOP_COUNT;
+
+	/* Can't call clk_get_rate as it locks a mutex and here we are spinlocked.
+	 * Use the value that we cached in the probe.
+	 */
+	cdiv = bi->cdiv;
+	clk_tout = bi->clk_tout;
+
+	if (bi->msg->flags & I2C_M_RD)
+		c |= BSC_C_INTR | BSC_C_READ;
+	else
+		c |= BSC_C_INTT;
+
+	bcm2708_wr(bi, BSC_CLKT, clk_tout);
+	bcm2708_wr(bi, BSC_DIV, cdiv);
+	bcm2708_wr(bi, BSC_A, bi->msg->addr);
+	bcm2708_wr(bi, BSC_DLEN, bi->msg->len);
+	if (combined)
+	{
+		/* Do the next two messages meet combined transaction criteria?
+		   - Current message is a write, next message is a read
+		   - Both messages to same slave address
+		   - Write message can fit inside FIFO (16 bytes or less) */
+		if ( (bi->nmsgs > 1) &&
+			!(bi->msg[0].flags & I2C_M_RD) && (bi->msg[1].flags & I2C_M_RD) &&
+			 (bi->msg[0].addr == bi->msg[1].addr) && (bi->msg[0].len <= 16)) {
+
+			/* Clear FIFO */
+			bcm2708_wr(bi, BSC_C, BSC_C_CLEAR_1);
+
+			/* Fill FIFO with entire write message (16 byte FIFO) */
+			while (bi->pos < bi->msg->len) {
+				bcm2708_wr(bi, BSC_FIFO, bi->msg->buf[bi->pos++]);
+			}
+			/* Start write transfer (no interrupts, don't clear FIFO) */
+			bcm2708_wr(bi, BSC_C, BSC_C_I2CEN | BSC_C_ST);
+
+			/* poll for transfer start bit (should only take 1-20 polls) */
+			do {
+				s = bcm2708_rd(bi, BSC_S);
+			} while (!(s & (BSC_S_TA | BSC_S_ERR | BSC_S_CLKT | BSC_S_DONE)) && --wait_loops >= 0);
+
+			/* did we time out or some error occured? */
+			if (wait_loops < 0 || (s & (BSC_S_ERR | BSC_S_CLKT))) {
+				return -1;
+			}
+
+			/* Send next read message before the write transfer finishes. */
+			bi->nmsgs--;
+			bi->msg++;
+			bi->pos = 0;
+			bcm2708_wr(bi, BSC_DLEN, bi->msg->len);
+			c = BSC_C_I2CEN | BSC_C_INTD | BSC_C_INTR | BSC_C_ST | BSC_C_READ;
+		}
+	}
+	bcm2708_wr(bi, BSC_C, c);
+
+	return 0;
+}
+
+static irqreturn_t bcm2708_i2c_interrupt(int irq, void *dev_id)
+{
+	struct bcm2708_i2c *bi = dev_id;
+	bool handled = true;
+	u32 s;
+	int ret;
+
+	spin_lock(&bi->lock);
+
+	/* we may see camera interrupts on the "other" I2C channel
+		   Just return if we've not sent anything */
+	if (!bi->nmsgs || !bi->msg) {
+		goto early_exit;
+	}
+
+	s = bcm2708_rd(bi, BSC_S);
+
+	if (s & (BSC_S_CLKT | BSC_S_ERR)) {
+		bcm2708_bsc_reset(bi);
+		bi->error = true;
+
+		bi->msg = 0; /* to inform the that all work is done */
+		bi->nmsgs = 0;
+		/* wake up our bh */
+		complete(&bi->done);
+	} else if (s & BSC_S_DONE) {
+		bi->nmsgs--;
+
+		if (bi->msg->flags & I2C_M_RD) {
+			bcm2708_bsc_fifo_drain(bi);
+		}
+
+		bcm2708_bsc_reset(bi);
+
+		if (bi->nmsgs) {
+			/* advance to next message */
+			bi->msg++;
+			bi->pos = 0;
+			ret = bcm2708_bsc_setup(bi);
+			if (ret < 0) {
+				bcm2708_bsc_reset(bi);
+				bi->error = true;
+				bi->msg = 0; /* to inform the that all work is done */
+				bi->nmsgs = 0;
+				/* wake up our bh */
+				complete(&bi->done);
+				goto early_exit;
+			}
+		} else {
+			bi->msg = 0; /* to inform the that all work is done */
+			bi->nmsgs = 0;
+			/* wake up our bh */
+			complete(&bi->done);
+		}
+	} else if (s & BSC_S_TXW) {
+		bcm2708_bsc_fifo_fill(bi);
+	} else if (s & BSC_S_RXR) {
+		bcm2708_bsc_fifo_drain(bi);
+	} else {
+		handled = false;
+	}
+
+early_exit:
+	spin_unlock(&bi->lock);
+
+	return handled ? IRQ_HANDLED : IRQ_NONE;
+}
+
+static int bcm2708_i2c_master_xfer(struct i2c_adapter *adap,
+	struct i2c_msg *msgs, int num)
+{
+	struct bcm2708_i2c *bi = adap->algo_data;
+	unsigned long flags;
+	int ret;
+
+	spin_lock_irqsave(&bi->lock, flags);
+
+	reinit_completion(&bi->done);
+	bi->msg = msgs;
+	bi->pos = 0;
+	bi->nmsgs = num;
+	bi->error = false;
+
+	ret = bcm2708_bsc_setup(bi);
+
+	spin_unlock_irqrestore(&bi->lock, flags);
+
+	/* check the result of the setup */
+	if (ret < 0)
+	{
+		dev_err(&adap->dev, "transfer setup timed out\n");
+		goto error_timeout;
+	}
+
+	ret = wait_for_completion_timeout(&bi->done, adap->timeout);
+	if (ret == 0) {
+		dev_err(&adap->dev, "transfer timed out\n");
+		goto error_timeout;
+	}
+
+	ret = bi->error ? -EIO : num;
+	return ret;
+
+error_timeout:
+	spin_lock_irqsave(&bi->lock, flags);
+	bcm2708_bsc_reset(bi);
+	bi->msg = 0; /* to inform the interrupt handler that there's nothing else to be done */
+	bi->nmsgs = 0;
+	spin_unlock_irqrestore(&bi->lock, flags);
+	return -ETIMEDOUT;
+}
+
+static u32 bcm2708_i2c_functionality(struct i2c_adapter *adap)
+{
+	return I2C_FUNC_I2C | /*I2C_FUNC_10BIT_ADDR |*/ I2C_FUNC_SMBUS_EMUL;
+}
+
+static struct i2c_algorithm bcm2708_i2c_algorithm = {
+	.master_xfer = bcm2708_i2c_master_xfer,
+	.functionality = bcm2708_i2c_functionality,
+};
+
+static int bcm2708_i2c_probe(struct platform_device *pdev)
+{
+	struct resource *regs;
+	int irq, err = -ENOMEM;
+	struct clk *clk;
+	struct bcm2708_i2c *bi;
+	struct i2c_adapter *adap;
+	unsigned long bus_hz;
+	u32 cdiv, clk_tout;
+	u32 baud;
+
+	baud = CONFIG_I2C_BCM2708_BAUDRATE;
+
+	if (pdev->dev.of_node) {
+		u32 bus_clk_rate;
+		pdev->id = of_alias_get_id(pdev->dev.of_node, "i2c");
+		if (pdev->id < 0) {
+			dev_err(&pdev->dev, "alias is missing\n");
+			return -EINVAL;
+		}
+		if (!of_property_read_u32(pdev->dev.of_node,
+					"clock-frequency", &bus_clk_rate))
+			baud = bus_clk_rate;
+		else
+			dev_warn(&pdev->dev,
+				"Could not read clock-frequency property\n");
+	}
+
+	if (baudrate)
+		baud = baudrate;
+
+	regs = platform_get_resource(pdev, IORESOURCE_MEM, 0);
+	if (!regs) {
+		dev_err(&pdev->dev, "could not get IO memory\n");
+		return -ENXIO;
+	}
+
+	irq = platform_get_irq(pdev, 0);
+	if (irq < 0) {
+		dev_err(&pdev->dev, "could not get IRQ\n");
+		return irq;
+	}
+
+	clk = clk_get(&pdev->dev, NULL);
+	if (IS_ERR(clk)) {
+		dev_err(&pdev->dev, "could not find clk: %ld\n", PTR_ERR(clk));
+		return PTR_ERR(clk);
+	}
+
+	err = clk_prepare_enable(clk);
+	if (err) {
+		dev_err(&pdev->dev, "could not enable clk: %d\n", err);
+		goto out_clk_put;
+	}
+
+	bi = kzalloc(sizeof(*bi), GFP_KERNEL);
+	if (!bi)
+		goto out_clk_disable;
+
+	platform_set_drvdata(pdev, bi);
+
+	adap = &bi->adapter;
+	adap->class = I2C_CLASS_HWMON | I2C_CLASS_DDC;
+	adap->algo = &bcm2708_i2c_algorithm;
+	adap->algo_data = bi;
+	adap->dev.parent = &pdev->dev;
+	adap->nr = pdev->id;
+	strlcpy(adap->name, dev_name(&pdev->dev), sizeof(adap->name));
+	adap->dev.of_node = pdev->dev.of_node;
+
+	switch (pdev->id) {
+	case 0:
+		adap->class = I2C_CLASS_HWMON;
+		break;
+	case 1:
+		adap->class = I2C_CLASS_DDC;
+		break;
+	case 2:
+		adap->class = I2C_CLASS_DDC;
+		break;
+	default:
+		dev_err(&pdev->dev, "can only bind to BSC 0, 1 or 2\n");
+		err = -ENXIO;
+		goto out_free_bi;
+	}
+
+	spin_lock_init(&bi->lock);
+	init_completion(&bi->done);
+
+	bi->base = ioremap(regs->start, resource_size(regs));
+	if (!bi->base) {
+		dev_err(&pdev->dev, "could not remap memory\n");
+		goto out_free_bi;
+	}
+
+	bi->irq = irq;
+	bi->clk = clk;
+
+	err = request_irq(irq, bcm2708_i2c_interrupt, IRQF_SHARED,
+			dev_name(&pdev->dev), bi);
+	if (err) {
+		dev_err(&pdev->dev, "could not request IRQ: %d\n", err);
+		goto out_iounmap;
+	}
+
+	bcm2708_bsc_reset(bi);
+
+	err = i2c_add_numbered_adapter(adap);
+	if (err < 0) {
+		dev_err(&pdev->dev, "could not add I2C adapter: %d\n", err);
+		goto out_free_irq;
+	}
+
+	bus_hz = clk_get_rate(bi->clk);
+	cdiv = bus_hz / baud;
+	if (cdiv > 0xffff) {
+		cdiv = 0xffff;
+		baud = bus_hz / cdiv;
+	}
+
+	clk_tout = 35/1000*baud; //35ms timeout as per SMBus specs.
+	if (clk_tout > 0xffff)
+		clk_tout = 0xffff;
+	
+	bi->cdiv = cdiv;
+	bi->clk_tout = clk_tout;
+
+	dev_info(&pdev->dev, "BSC%d Controller at 0x%08lx (irq %d) (baudrate %d)\n",
+		pdev->id, (unsigned long)regs->start, irq, baud);
+
+	return 0;
+
+out_free_irq:
+	free_irq(bi->irq, bi);
+out_iounmap:
+	iounmap(bi->base);
+out_free_bi:
+	kfree(bi);
+out_clk_disable:
+	clk_disable_unprepare(clk);
+out_clk_put:
+	clk_put(clk);
+	return err;
+}
+
+static int bcm2708_i2c_remove(struct platform_device *pdev)
+{
+	struct bcm2708_i2c *bi = platform_get_drvdata(pdev);
+
+	platform_set_drvdata(pdev, NULL);
+
+	i2c_del_adapter(&bi->adapter);
+	free_irq(bi->irq, bi);
+	iounmap(bi->base);
+	clk_disable_unprepare(bi->clk);
+	clk_put(bi->clk);
+	kfree(bi);
+
+	return 0;
+}
+
+static const struct of_device_id bcm2708_i2c_of_match[] = {
+        { .compatible = "brcm,bcm2708-i2c" },
+        {},
+};
+MODULE_DEVICE_TABLE(of, bcm2708_i2c_of_match);
+
+static struct platform_driver bcm2708_i2c_driver = {
+	.driver		= {
+		.name	= DRV_NAME,
+		.owner	= THIS_MODULE,
+		.of_match_table = bcm2708_i2c_of_match,
+	},
+	.probe		= bcm2708_i2c_probe,
+	.remove		= bcm2708_i2c_remove,
+};
+
+// module_platform_driver(bcm2708_i2c_driver);
+
+
+static int __init bcm2708_i2c_init(void)
+{
+	return platform_driver_register(&bcm2708_i2c_driver);
+}
+
+static void __exit bcm2708_i2c_exit(void)
+{
+	platform_driver_unregister(&bcm2708_i2c_driver);
+}
+
+module_init(bcm2708_i2c_init);
+module_exit(bcm2708_i2c_exit);
+
+
+
+MODULE_DESCRIPTION("BSC controller driver for Broadcom BCM2708");
+MODULE_AUTHOR("Chris Boot <bootc@bootc.net>");
+MODULE_LICENSE("GPL v2");
+MODULE_ALIAS("platform:" DRV_NAME);