summaryrefslogtreecommitdiffstats
path: root/drivers/spi/spi-tegra.c
blob: a43ceeb1063a7514389063797c94ee805a90cefb (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
/*
 * Driver for Nvidia TEGRA spi controller.
 *
 * Copyright (C) 2010 Google, Inc.
 *
 * Author:
 *     Erik Gilling <konkers@android.com>
 *
 * This software is licensed under the terms of the GNU General Public
 * License version 2, as published by the Free Software Foundation, and
 * may be copied, distributed, and modified under those terms.
 *
 * 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.
 *
 */

#include <linux/kernel.h>
#include <linux/init.h>
#include <linux/err.h>
#include <linux/platform_device.h>
#include <linux/io.h>
#include <linux/dma-mapping.h>
#include <linux/dmapool.h>
#include <linux/clk.h>
#include <linux/interrupt.h>
#include <linux/delay.h>

#include <linux/spi/spi.h>

#include <mach/dma.h>

#define SLINK_COMMAND		0x000
#define   SLINK_BIT_LENGTH(x)		(((x) & 0x1f) << 0)
#define   SLINK_WORD_SIZE(x)		(((x) & 0x1f) << 5)
#define   SLINK_BOTH_EN			(1 << 10)
#define   SLINK_CS_SW			(1 << 11)
#define   SLINK_CS_VALUE		(1 << 12)
#define   SLINK_CS_POLARITY		(1 << 13)
#define   SLINK_IDLE_SDA_DRIVE_LOW	(0 << 16)
#define   SLINK_IDLE_SDA_DRIVE_HIGH	(1 << 16)
#define   SLINK_IDLE_SDA_PULL_LOW	(2 << 16)
#define   SLINK_IDLE_SDA_PULL_HIGH	(3 << 16)
#define   SLINK_IDLE_SDA_MASK		(3 << 16)
#define   SLINK_CS_POLARITY1		(1 << 20)
#define   SLINK_CK_SDA			(1 << 21)
#define   SLINK_CS_POLARITY2		(1 << 22)
#define   SLINK_CS_POLARITY3		(1 << 23)
#define   SLINK_IDLE_SCLK_DRIVE_LOW	(0 << 24)
#define   SLINK_IDLE_SCLK_DRIVE_HIGH	(1 << 24)
#define   SLINK_IDLE_SCLK_PULL_LOW	(2 << 24)
#define   SLINK_IDLE_SCLK_PULL_HIGH	(3 << 24)
#define   SLINK_IDLE_SCLK_MASK		(3 << 24)
#define   SLINK_M_S			(1 << 28)
#define   SLINK_WAIT			(1 << 29)
#define   SLINK_GO			(1 << 30)
#define   SLINK_ENB			(1 << 31)

#define SLINK_COMMAND2		0x004
#define   SLINK_LSBFE			(1 << 0)
#define   SLINK_SSOE			(1 << 1)
#define   SLINK_SPIE			(1 << 4)
#define   SLINK_BIDIROE			(1 << 6)
#define   SLINK_MODFEN			(1 << 7)
#define   SLINK_INT_SIZE(x)		(((x) & 0x1f) << 8)
#define   SLINK_CS_ACTIVE_BETWEEN	(1 << 17)
#define   SLINK_SS_EN_CS(x)		(((x) & 0x3) << 18)
#define   SLINK_SS_SETUP(x)		(((x) & 0x3) << 20)
#define   SLINK_FIFO_REFILLS_0		(0 << 22)
#define   SLINK_FIFO_REFILLS_1		(1 << 22)
#define   SLINK_FIFO_REFILLS_2		(2 << 22)
#define   SLINK_FIFO_REFILLS_3		(3 << 22)
#define   SLINK_FIFO_REFILLS_MASK	(3 << 22)
#define   SLINK_WAIT_PACK_INT(x)	(((x) & 0x7) << 26)
#define   SLINK_SPC0			(1 << 29)
#define   SLINK_TXEN			(1 << 30)
#define   SLINK_RXEN			(1 << 31)

#define SLINK_STATUS		0x008
#define   SLINK_COUNT(val)		(((val) >> 0) & 0x1f)
#define   SLINK_WORD(val)		(((val) >> 5) & 0x1f)
#define   SLINK_BLK_CNT(val)		(((val) >> 0) & 0xffff)
#define   SLINK_MODF			(1 << 16)
#define   SLINK_RX_UNF			(1 << 18)
#define   SLINK_TX_OVF			(1 << 19)
#define   SLINK_TX_FULL			(1 << 20)
#define   SLINK_TX_EMPTY		(1 << 21)
#define   SLINK_RX_FULL			(1 << 22)
#define   SLINK_RX_EMPTY		(1 << 23)
#define   SLINK_TX_UNF			(1 << 24)
#define   SLINK_RX_OVF			(1 << 25)
#define   SLINK_TX_FLUSH		(1 << 26)
#define   SLINK_RX_FLUSH		(1 << 27)
#define   SLINK_SCLK			(1 << 28)
#define   SLINK_ERR			(1 << 29)
#define   SLINK_RDY			(1 << 30)
#define   SLINK_BSY			(1 << 31)

#define SLINK_MAS_DATA		0x010
#define SLINK_SLAVE_DATA	0x014

#define SLINK_DMA_CTL		0x018
#define   SLINK_DMA_BLOCK_SIZE(x)	(((x) & 0xffff) << 0)
#define   SLINK_TX_TRIG_1		(0 << 16)
#define   SLINK_TX_TRIG_4		(1 << 16)
#define   SLINK_TX_TRIG_8		(2 << 16)
#define   SLINK_TX_TRIG_16		(3 << 16)
#define   SLINK_TX_TRIG_MASK		(3 << 16)
#define   SLINK_RX_TRIG_1		(0 << 18)
#define   SLINK_RX_TRIG_4		(1 << 18)
#define   SLINK_RX_TRIG_8		(2 << 18)
#define   SLINK_RX_TRIG_16		(3 << 18)
#define   SLINK_RX_TRIG_MASK		(3 << 18)
#define   SLINK_PACKED			(1 << 20)
#define   SLINK_PACK_SIZE_4		(0 << 21)
#define   SLINK_PACK_SIZE_8		(1 << 21)
#define   SLINK_PACK_SIZE_16		(2 << 21)
#define   SLINK_PACK_SIZE_32		(3 << 21)
#define   SLINK_PACK_SIZE_MASK		(3 << 21)
#define   SLINK_IE_TXC			(1 << 26)
#define   SLINK_IE_RXC			(1 << 27)
#define   SLINK_DMA_EN			(1 << 31)

#define SLINK_STATUS2		0x01c
#define   SLINK_TX_FIFO_EMPTY_COUNT(val)	(((val) & 0x3f) >> 0)
#define   SLINK_RX_FIFO_FULL_COUNT(val)		(((val) & 0x3f) >> 16)

#define SLINK_TX_FIFO		0x100
#define SLINK_RX_FIFO		0x180

static const unsigned long spi_tegra_req_sels[] = {
	TEGRA_DMA_REQ_SEL_SL2B1,
	TEGRA_DMA_REQ_SEL_SL2B2,
	TEGRA_DMA_REQ_SEL_SL2B3,
	TEGRA_DMA_REQ_SEL_SL2B4,
};

#define BB_LEN			32

struct spi_tegra_data {
	struct spi_master	*master;
	struct platform_device	*pdev;
	spinlock_t		lock;

	struct clk		*clk;
	void __iomem		*base;
	unsigned long		phys;

	u32			cur_speed;

	struct list_head	queue;
	struct spi_transfer	*cur;
	unsigned		cur_pos;
	unsigned		cur_len;
	unsigned		cur_bytes_per_word;

	/* The tegra spi controller has a bug which causes the first word
	 * in PIO transactions to be garbage.  Since packed DMA transactions
	 * require transfers to be 4 byte aligned we need a bounce buffer
	 * for the generic case.
	 */
	struct tegra_dma_req	rx_dma_req;
	struct tegra_dma_channel *rx_dma;
	u32			*rx_bb;
	dma_addr_t		rx_bb_phys;
};


static inline unsigned long spi_tegra_readl(struct spi_tegra_data *tspi,
					    unsigned long reg)
{
	return readl(tspi->base + reg);
}

static inline void spi_tegra_writel(struct spi_tegra_data *tspi,
				    unsigned long val,
				    unsigned long reg)
{
	writel(val, tspi->base + reg);
}

static void spi_tegra_go(struct spi_tegra_data *tspi)
{
	unsigned long val;

	wmb();

	val = spi_tegra_readl(tspi, SLINK_DMA_CTL);
	val &= ~SLINK_DMA_BLOCK_SIZE(~0) & ~SLINK_DMA_EN;
	val |= SLINK_DMA_BLOCK_SIZE(tspi->rx_dma_req.size / 4 - 1);
	spi_tegra_writel(tspi, val, SLINK_DMA_CTL);

	tegra_dma_enqueue_req(tspi->rx_dma, &tspi->rx_dma_req);

	val |= SLINK_DMA_EN;
	spi_tegra_writel(tspi, val, SLINK_DMA_CTL);
}

static unsigned spi_tegra_fill_tx_fifo(struct spi_tegra_data *tspi,
				  struct spi_transfer *t)
{
	unsigned len = min(t->len - tspi->cur_pos, BB_LEN *
			   tspi->cur_bytes_per_word);
	u8 *tx_buf = (u8 *)t->tx_buf + tspi->cur_pos;
	int i, j;
	unsigned long val;

	val = spi_tegra_readl(tspi, SLINK_COMMAND);
	val &= ~SLINK_WORD_SIZE(~0);
	val |= SLINK_WORD_SIZE(len / tspi->cur_bytes_per_word - 1);
	spi_tegra_writel(tspi, val, SLINK_COMMAND);

	for (i = 0; i < len; i += tspi->cur_bytes_per_word) {
		val = 0;
		for (j = 0; j < tspi->cur_bytes_per_word; j++)
			val |= tx_buf[i + j] << j * 8;

		spi_tegra_writel(tspi, val, SLINK_TX_FIFO);
	}

	tspi->rx_dma_req.size = len / tspi->cur_bytes_per_word * 4;

	return len;
}

static unsigned spi_tegra_drain_rx_fifo(struct spi_tegra_data *tspi,
				  struct spi_transfer *t)
{
	unsigned len = tspi->cur_len;
	u8 *rx_buf = (u8 *)t->rx_buf + tspi->cur_pos;
	int i, j;
	unsigned long val;

	for (i = 0; i < len; i += tspi->cur_bytes_per_word) {
		val = tspi->rx_bb[i / tspi->cur_bytes_per_word];
		for (j = 0; j < tspi->cur_bytes_per_word; j++)
			rx_buf[i + j] = (val >> (j * 8)) & 0xff;
	}

	return len;
}

static void spi_tegra_start_transfer(struct spi_device *spi,
				    struct spi_transfer *t)
{
	struct spi_tegra_data *tspi = spi_master_get_devdata(spi->master);
	u32 speed;
	u8 bits_per_word;
	unsigned long val;

	speed = t->speed_hz ? t->speed_hz : spi->max_speed_hz;
	bits_per_word = t->bits_per_word ? t->bits_per_word  :
		spi->bits_per_word;

	tspi->cur_bytes_per_word = (bits_per_word - 1) / 8 + 1;

	if (speed != tspi->cur_speed)
		clk_set_rate(tspi->clk, speed);

	if (tspi->cur_speed == 0)
		clk_enable(tspi->clk);

	tspi->cur_speed = speed;

	val = spi_tegra_readl(tspi, SLINK_COMMAND2);
	val &= ~SLINK_SS_EN_CS(~0) | SLINK_RXEN | SLINK_TXEN;
	if (t->rx_buf)
		val |= SLINK_RXEN;
	if (t->tx_buf)
		val |= SLINK_TXEN;
	val |= SLINK_SS_EN_CS(spi->chip_select);
	val |= SLINK_SPIE;
	spi_tegra_writel(tspi, val, SLINK_COMMAND2);

	val = spi_tegra_readl(tspi, SLINK_COMMAND);
	val &= ~SLINK_BIT_LENGTH(~0);
	val |= SLINK_BIT_LENGTH(bits_per_word - 1);

	/* FIXME: should probably control CS manually so that we can be sure
	 * it does not go low between transfer and to support delay_usecs
	 * correctly.
	 */
	val &= ~SLINK_IDLE_SCLK_MASK & ~SLINK_CK_SDA & ~SLINK_CS_SW;

	if (spi->mode & SPI_CPHA)
		val |= SLINK_CK_SDA;

	if (spi->mode & SPI_CPOL)
		val |= SLINK_IDLE_SCLK_DRIVE_HIGH;
	else
		val |= SLINK_IDLE_SCLK_DRIVE_LOW;

	val |= SLINK_M_S;

	spi_tegra_writel(tspi, val, SLINK_COMMAND);

	spi_tegra_writel(tspi, SLINK_RX_FLUSH | SLINK_TX_FLUSH, SLINK_STATUS);

	tspi->cur = t;
	tspi->cur_pos = 0;
	tspi->cur_len = spi_tegra_fill_tx_fifo(tspi, t);

	spi_tegra_go(tspi);
}

static void spi_tegra_start_message(struct spi_device *spi,
				    struct spi_message *m)
{
	struct spi_transfer *t;

	m->actual_length = 0;
	m->status = 0;

	t = list_first_entry(&m->transfers, struct spi_transfer, transfer_list);
	spi_tegra_start_transfer(spi, t);
}

static void tegra_spi_rx_dma_complete(struct tegra_dma_req *req)
{
	struct spi_tegra_data *tspi = req->dev;
	unsigned long flags;
	struct spi_message *m;
	struct spi_device *spi;
	int timeout = 0;
	unsigned long val;

	/* the SPI controller may come back with both the BSY and RDY bits
	 * set.  In this case we need to wait for the BSY bit to clear so
	 * that we are sure the DMA is finished.  1000 reads was empirically
	 * determined to be long enough.
	 */
	while (timeout++ < 1000) {
		if (!(spi_tegra_readl(tspi, SLINK_STATUS) & SLINK_BSY))
			break;
	}

	spin_lock_irqsave(&tspi->lock, flags);

	val = spi_tegra_readl(tspi, SLINK_STATUS);
	val |= SLINK_RDY;
	spi_tegra_writel(tspi, val, SLINK_STATUS);

	m = list_first_entry(&tspi->queue, struct spi_message, queue);

	if (timeout >= 1000)
		m->status = -EIO;

	spi = m->state;

	tspi->cur_pos += spi_tegra_drain_rx_fifo(tspi, tspi->cur);
	m->actual_length += tspi->cur_pos;

	if (tspi->cur_pos < tspi->cur->len) {
		tspi->cur_len = spi_tegra_fill_tx_fifo(tspi, tspi->cur);
		spi_tegra_go(tspi);
	} else if (!list_is_last(&tspi->cur->transfer_list,
				 &m->transfers)) {
		tspi->cur =  list_first_entry(&tspi->cur->transfer_list,
					      struct spi_transfer,
					      transfer_list);
		spi_tegra_start_transfer(spi, tspi->cur);
	} else {
		list_del(&m->queue);

		m->complete(m->context);

		if (!list_empty(&tspi->queue)) {
			m = list_first_entry(&tspi->queue, struct spi_message,
					     queue);
			spi = m->state;
			spi_tegra_start_message(spi, m);
		} else {
			clk_disable(tspi->clk);
			tspi->cur_speed = 0;
		}
	}

	spin_unlock_irqrestore(&tspi->lock, flags);
}

static int spi_tegra_setup(struct spi_device *spi)
{
	struct spi_tegra_data *tspi = spi_master_get_devdata(spi->master);
	unsigned long cs_bit;
	unsigned long val;
	unsigned long flags;

	dev_dbg(&spi->dev, "setup %d bpw, %scpol, %scpha, %dHz\n",
		spi->bits_per_word,
		spi->mode & SPI_CPOL ? "" : "~",
		spi->mode & SPI_CPHA ? "" : "~",
		spi->max_speed_hz);


	switch (spi->chip_select) {
	case 0:
		cs_bit = SLINK_CS_POLARITY;
		break;

	case 1:
		cs_bit = SLINK_CS_POLARITY1;
		break;

	case 2:
		cs_bit = SLINK_CS_POLARITY2;
		break;

	case 4:
		cs_bit = SLINK_CS_POLARITY3;
		break;

	default:
		return -EINVAL;
	}

	spin_lock_irqsave(&tspi->lock, flags);

	val = spi_tegra_readl(tspi, SLINK_COMMAND);
	if (spi->mode & SPI_CS_HIGH)
		val |= cs_bit;
	else
		val &= ~cs_bit;
	spi_tegra_writel(tspi, val, SLINK_COMMAND);

	spin_unlock_irqrestore(&tspi->lock, flags);

	return 0;
}

static int spi_tegra_transfer(struct spi_device *spi, struct spi_message *m)
{
	struct spi_tegra_data *tspi = spi_master_get_devdata(spi->master);
	struct spi_transfer *t;
	unsigned long flags;
	int was_empty;

	if (list_empty(&m->transfers) || !m->complete)
		return -EINVAL;

	list_for_each_entry(t, &m->transfers, transfer_list) {
		if (t->bits_per_word < 0 || t->bits_per_word > 32)
			return -EINVAL;

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

		if (!t->rx_buf && !t->tx_buf)
			return -EINVAL;
	}

	m->state = spi;

	spin_lock_irqsave(&tspi->lock, flags);
	was_empty = list_empty(&tspi->queue);
	list_add_tail(&m->queue, &tspi->queue);

	if (was_empty)
		spi_tegra_start_message(spi, m);

	spin_unlock_irqrestore(&tspi->lock, flags);

	return 0;
}

static int __init spi_tegra_probe(struct platform_device *pdev)
{
	struct spi_master	*master;
	struct spi_tegra_data	*tspi;
	struct resource		*r;
	int ret;

	master = spi_alloc_master(&pdev->dev, sizeof *tspi);
	if (master == NULL) {
		dev_err(&pdev->dev, "master allocation failed\n");
		return -ENOMEM;
	}

	/* the spi->mode bits understood by this driver: */
	master->mode_bits = SPI_CPOL | SPI_CPHA | SPI_CS_HIGH;

	master->bus_num = pdev->id;

	master->setup = spi_tegra_setup;
	master->transfer = spi_tegra_transfer;
	master->num_chipselect = 4;

	dev_set_drvdata(&pdev->dev, master);
	tspi = spi_master_get_devdata(master);
	tspi->master = master;
	tspi->pdev = pdev;
	spin_lock_init(&tspi->lock);

	r = platform_get_resource(pdev, IORESOURCE_MEM, 0);
	if (r == NULL) {
		ret = -ENODEV;
		goto err0;
	}

	if (!request_mem_region(r->start, resource_size(r),
				dev_name(&pdev->dev))) {
		ret = -EBUSY;
		goto err0;
	}

	tspi->phys = r->start;
	tspi->base = ioremap(r->start, resource_size(r));
	if (!tspi->base) {
		dev_err(&pdev->dev, "can't ioremap iomem\n");
		ret = -ENOMEM;
		goto err1;
	}

	tspi->clk = clk_get(&pdev->dev, NULL);
	if (IS_ERR(tspi->clk)) {
		dev_err(&pdev->dev, "can not get clock\n");
		ret = PTR_ERR(tspi->clk);
		goto err2;
	}

	INIT_LIST_HEAD(&tspi->queue);

	tspi->rx_dma = tegra_dma_allocate_channel(TEGRA_DMA_MODE_ONESHOT);
	if (!tspi->rx_dma) {
		dev_err(&pdev->dev, "can not allocate rx dma channel\n");
		ret = -ENODEV;
		goto err3;
	}

	tspi->rx_bb = dma_alloc_coherent(&pdev->dev, sizeof(u32) * BB_LEN,
					 &tspi->rx_bb_phys, GFP_KERNEL);
	if (!tspi->rx_bb) {
		dev_err(&pdev->dev, "can not allocate rx bounce buffer\n");
		ret = -ENOMEM;
		goto err4;
	}

	tspi->rx_dma_req.complete = tegra_spi_rx_dma_complete;
	tspi->rx_dma_req.to_memory = 1;
	tspi->rx_dma_req.dest_addr = tspi->rx_bb_phys;
	tspi->rx_dma_req.dest_bus_width = 32;
	tspi->rx_dma_req.source_addr = tspi->phys + SLINK_RX_FIFO;
	tspi->rx_dma_req.source_bus_width = 32;
	tspi->rx_dma_req.source_wrap = 4;
	tspi->rx_dma_req.req_sel = spi_tegra_req_sels[pdev->id];
	tspi->rx_dma_req.dev = tspi;

	master->dev.of_node = pdev->dev.of_node;
	ret = spi_register_master(master);

	if (ret < 0)
		goto err5;

	return ret;

err5:
	dma_free_coherent(&pdev->dev, sizeof(u32) * BB_LEN,
			  tspi->rx_bb, tspi->rx_bb_phys);
err4:
	tegra_dma_free_channel(tspi->rx_dma);
err3:
	clk_put(tspi->clk);
err2:
	iounmap(tspi->base);
err1:
	release_mem_region(r->start, resource_size(r));
err0:
	spi_master_put(master);
	return ret;
}

static int __devexit spi_tegra_remove(struct platform_device *pdev)
{
	struct spi_master	*master;
	struct spi_tegra_data	*tspi;
	struct resource		*r;

	master = dev_get_drvdata(&pdev->dev);
	tspi = spi_master_get_devdata(master);

	spi_unregister_master(master);
	tegra_dma_free_channel(tspi->rx_dma);

	dma_free_coherent(&pdev->dev, sizeof(u32) * BB_LEN,
			  tspi->rx_bb, tspi->rx_bb_phys);

	clk_put(tspi->clk);
	iounmap(tspi->base);

	r = platform_get_resource(pdev, IORESOURCE_MEM, 0);
	release_mem_region(r->start, resource_size(r));

	return 0;
}

MODULE_ALIAS("platform:spi_tegra");

#ifdef CONFIG_OF
static struct of_device_id spi_tegra_of_match_table[] __devinitdata = {
	{ .compatible = "nvidia,tegra250-spi", },
	{}
};
MODULE_DEVICE_TABLE(of, spi_tegra_of_match_table);
#else /* CONFIG_OF */
#define spi_tegra_of_match_table NULL
#endif /* CONFIG_OF */

static struct platform_driver spi_tegra_driver = {
	.driver = {
		.name =		"spi_tegra",
		.owner =	THIS_MODULE,
		.of_match_table = spi_tegra_of_match_table,
	},
	.remove =	__devexit_p(spi_tegra_remove),
};

static int __init spi_tegra_init(void)
{
	return platform_driver_probe(&spi_tegra_driver, spi_tegra_probe);
}
module_init(spi_tegra_init);

static void __exit spi_tegra_exit(void)
{
	platform_driver_unregister(&spi_tegra_driver);
}
module_exit(spi_tegra_exit);

MODULE_LICENSE("GPL");