summaryrefslogtreecommitdiffstats
path: root/drivers/spi/spi_sh_msiof.c
blob: 30973ec16a93d6bd3d0968b04bd3d8b81f534c33 (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
/*
 * SuperH MSIOF SPI Master Interface
 *
 * Copyright (c) 2009 Magnus Damm
 *
 * This program is free software; you can redistribute it and/or modify
 * it under the terms of the GNU General Public License version 2 as
 * published by the Free Software Foundation.
 *
 */

#include <linux/kernel.h>
#include <linux/init.h>
#include <linux/delay.h>
#include <linux/interrupt.h>
#include <linux/platform_device.h>
#include <linux/completion.h>
#include <linux/pm_runtime.h>
#include <linux/gpio.h>
#include <linux/bitmap.h>
#include <linux/clk.h>
#include <linux/io.h>

#include <linux/spi/spi.h>
#include <linux/spi/spi_bitbang.h>
#include <linux/spi/sh_msiof.h>

#include <asm/spi.h>
#include <asm/unaligned.h>

struct sh_msiof_spi_priv {
	struct spi_bitbang bitbang; /* must be first for spi_bitbang.c */
	void __iomem *mapbase;
	struct clk *clk;
	struct platform_device *pdev;
	struct sh_msiof_spi_info *info;
	struct completion done;
	unsigned long flags;
	int tx_fifo_size;
	int rx_fifo_size;
};

#define TMDR1	0x00
#define TMDR2	0x04
#define TMDR3	0x08
#define RMDR1	0x10
#define RMDR2	0x14
#define RMDR3	0x18
#define TSCR	0x20
#define RSCR	0x22
#define CTR	0x28
#define FCTR	0x30
#define STR	0x40
#define IER	0x44
#define TDR1	0x48
#define TDR2	0x4c
#define TFDR	0x50
#define RDR1	0x58
#define RDR2	0x5c
#define RFDR	0x60

#define CTR_TSCKE (1 << 15)
#define CTR_TFSE  (1 << 14)
#define CTR_TXE   (1 << 9)
#define CTR_RXE   (1 << 8)

#define STR_TEOF  (1 << 23)
#define STR_REOF  (1 << 7)

static unsigned long sh_msiof_read(struct sh_msiof_spi_priv *p, int reg_offs)
{
	switch (reg_offs) {
	case TSCR:
	case RSCR:
		return ioread16(p->mapbase + reg_offs);
	default:
		return ioread32(p->mapbase + reg_offs);
	}
}

static void sh_msiof_write(struct sh_msiof_spi_priv *p, int reg_offs,
			   unsigned long value)
{
	switch (reg_offs) {
	case TSCR:
	case RSCR:
		iowrite16(value, p->mapbase + reg_offs);
		break;
	default:
		iowrite32(value, p->mapbase + reg_offs);
		break;
	}
}

static int sh_msiof_modify_ctr_wait(struct sh_msiof_spi_priv *p,
				    unsigned long clr, unsigned long set)
{
	unsigned long mask = clr | set;
	unsigned long data;
	int k;

	data = sh_msiof_read(p, CTR);
	data &= ~clr;
	data |= set;
	sh_msiof_write(p, CTR, data);

	for (k = 100; k > 0; k--) {
		if ((sh_msiof_read(p, CTR) & mask) == set)
			break;

		udelay(10);
	}

	return k > 0 ? 0 : -ETIMEDOUT;
}

static irqreturn_t sh_msiof_spi_irq(int irq, void *data)
{
	struct sh_msiof_spi_priv *p = data;

	/* just disable the interrupt and wake up */
	sh_msiof_write(p, IER, 0);
	complete(&p->done);

	return IRQ_HANDLED;
}

static struct {
	unsigned short div;
	unsigned short scr;
} const sh_msiof_spi_clk_table[] = {
	{ 1, 0x0007 },
	{ 2, 0x0000 },
	{ 4, 0x0001 },
	{ 8, 0x0002 },
	{ 16, 0x0003 },
	{ 32, 0x0004 },
	{ 64, 0x1f00 },
	{ 128, 0x1f01 },
	{ 256, 0x1f02 },
	{ 512, 0x1f03 },
	{ 1024, 0x1f04 },
};

static void sh_msiof_spi_set_clk_regs(struct sh_msiof_spi_priv *p,
				      unsigned long parent_rate,
				      unsigned long spi_hz)
{
	unsigned long div = 1024;
	size_t k;

	if (!WARN_ON(!spi_hz || !parent_rate))
		div = parent_rate / spi_hz;

	/* TODO: make more fine grained */

	for (k = 0; k < ARRAY_SIZE(sh_msiof_spi_clk_table); k++) {
		if (sh_msiof_spi_clk_table[k].div >= div)
			break;
	}

	k = min_t(int, k, ARRAY_SIZE(sh_msiof_spi_clk_table) - 1);

	sh_msiof_write(p, TSCR, sh_msiof_spi_clk_table[k].scr);
	sh_msiof_write(p, RSCR, sh_msiof_spi_clk_table[k].scr);
}

static void sh_msiof_spi_set_pin_regs(struct sh_msiof_spi_priv *p,
				      int cpol, int cpha,
				      int tx_hi_z, int lsb_first)
{
	unsigned long tmp;
	int edge;

	/*
	 * CPOL CPHA     TSCKIZ RSCKIZ TEDG REDG
	 *    0    0         10     10    1    1
	 *    0    1         10     10    0    0
	 *    1    0         11     11    0    0
	 *    1    1         11     11    1    1
	 */
	sh_msiof_write(p, FCTR, 0);
	sh_msiof_write(p, TMDR1, 0xe2000005 | (lsb_first << 24));
	sh_msiof_write(p, RMDR1, 0x22000005 | (lsb_first << 24));

	tmp = 0xa0000000;
	tmp |= cpol << 30; /* TSCKIZ */
	tmp |= cpol << 28; /* RSCKIZ */

	edge = cpol ? cpha : !cpha;

	tmp |= edge << 27; /* TEDG */
	tmp |= edge << 26; /* REDG */
	tmp |= (tx_hi_z ? 2 : 0) << 22; /* TXDIZ */
	sh_msiof_write(p, CTR, tmp);
}

static void sh_msiof_spi_set_mode_regs(struct sh_msiof_spi_priv *p,
				       const void *tx_buf, void *rx_buf,
				       int bits, int words)
{
	unsigned long dr2;

	dr2 = ((bits - 1) << 24) | ((words - 1) << 16);

	if (tx_buf)
		sh_msiof_write(p, TMDR2, dr2);
	else
		sh_msiof_write(p, TMDR2, dr2 | 1);

	if (rx_buf)
		sh_msiof_write(p, RMDR2, dr2);

	sh_msiof_write(p, IER, STR_TEOF | STR_REOF);
}

static void sh_msiof_reset_str(struct sh_msiof_spi_priv *p)
{
	sh_msiof_write(p, STR, sh_msiof_read(p, STR));
}

static void sh_msiof_spi_write_fifo_8(struct sh_msiof_spi_priv *p,
				      const void *tx_buf, int words, int fs)
{
	const unsigned char *buf_8 = tx_buf;
	int k;

	for (k = 0; k < words; k++)
		sh_msiof_write(p, TFDR, buf_8[k] << fs);
}

static void sh_msiof_spi_write_fifo_16(struct sh_msiof_spi_priv *p,
				       const void *tx_buf, int words, int fs)
{
	const unsigned short *buf_16 = tx_buf;
	int k;

	for (k = 0; k < words; k++)
		sh_msiof_write(p, TFDR, buf_16[k] << fs);
}

static void sh_msiof_spi_write_fifo_16u(struct sh_msiof_spi_priv *p,
					const void *tx_buf, int words, int fs)
{
	const unsigned short *buf_16 = tx_buf;
	int k;

	for (k = 0; k < words; k++)
		sh_msiof_write(p, TFDR, get_unaligned(&buf_16[k]) << fs);
}

static void sh_msiof_spi_write_fifo_32(struct sh_msiof_spi_priv *p,
				       const void *tx_buf, int words, int fs)
{
	const unsigned int *buf_32 = tx_buf;
	int k;

	for (k = 0; k < words; k++)
		sh_msiof_write(p, TFDR, buf_32[k] << fs);
}

static void sh_msiof_spi_write_fifo_32u(struct sh_msiof_spi_priv *p,
					const void *tx_buf, int words, int fs)
{
	const unsigned int *buf_32 = tx_buf;
	int k;

	for (k = 0; k < words; k++)
		sh_msiof_write(p, TFDR, get_unaligned(&buf_32[k]) << fs);
}

static void sh_msiof_spi_read_fifo_8(struct sh_msiof_spi_priv *p,
				     void *rx_buf, int words, int fs)
{
	unsigned char *buf_8 = rx_buf;
	int k;

	for (k = 0; k < words; k++)
		buf_8[k] = sh_msiof_read(p, RFDR) >> fs;
}

static void sh_msiof_spi_read_fifo_16(struct sh_msiof_spi_priv *p,
				      void *rx_buf, int words, int fs)
{
	unsigned short *buf_16 = rx_buf;
	int k;

	for (k = 0; k < words; k++)
		buf_16[k] = sh_msiof_read(p, RFDR) >> fs;
}

static void sh_msiof_spi_read_fifo_16u(struct sh_msiof_spi_priv *p,
				       void *rx_buf, int words, int fs)
{
	unsigned short *buf_16 = rx_buf;
	int k;

	for (k = 0; k < words; k++)
		put_unaligned(sh_msiof_read(p, RFDR) >> fs, &buf_16[k]);
}

static void sh_msiof_spi_read_fifo_32(struct sh_msiof_spi_priv *p,
				      void *rx_buf, int words, int fs)
{
	unsigned int *buf_32 = rx_buf;
	int k;

	for (k = 0; k < words; k++)
		buf_32[k] = sh_msiof_read(p, RFDR) >> fs;
}

static void sh_msiof_spi_read_fifo_32u(struct sh_msiof_spi_priv *p,
				       void *rx_buf, int words, int fs)
{
	unsigned int *buf_32 = rx_buf;
	int k;

	for (k = 0; k < words; k++)
		put_unaligned(sh_msiof_read(p, RFDR) >> fs, &buf_32[k]);
}

static int sh_msiof_spi_bits(struct spi_device *spi, struct spi_transfer *t)
{
	int bits;

	bits = t ? t->bits_per_word : 0;
	bits = bits ? bits : spi->bits_per_word;
	return bits;
}

static unsigned long sh_msiof_spi_hz(struct spi_device *spi,
				     struct spi_transfer *t)
{
	unsigned long hz;

	hz = t ? t->speed_hz : 0;
	hz = hz ? hz : spi->max_speed_hz;
	return hz;
}

static int sh_msiof_spi_setup_transfer(struct spi_device *spi,
				       struct spi_transfer *t)
{
	int bits;

	/* noting to check hz values against since parent clock is disabled */

	bits = sh_msiof_spi_bits(spi, t);
	if (bits < 8)
		return -EINVAL;
	if (bits > 32)
		return -EINVAL;

	return spi_bitbang_setup_transfer(spi, t);
}

static void sh_msiof_spi_chipselect(struct spi_device *spi, int is_on)
{
	struct sh_msiof_spi_priv *p = spi_master_get_devdata(spi->master);
	int value;

	/* chip select is active low unless SPI_CS_HIGH is set */
	if (spi->mode & SPI_CS_HIGH)
		value = (is_on == BITBANG_CS_ACTIVE) ? 1 : 0;
	else
		value = (is_on == BITBANG_CS_ACTIVE) ? 0 : 1;

	if (is_on == BITBANG_CS_ACTIVE) {
		if (!test_and_set_bit(0, &p->flags)) {
			pm_runtime_get_sync(&p->pdev->dev);
			clk_enable(p->clk);
		}

		/* Configure pins before asserting CS */
		sh_msiof_spi_set_pin_regs(p, !!(spi->mode & SPI_CPOL),
					  !!(spi->mode & SPI_CPHA),
					  !!(spi->mode & SPI_3WIRE),
					  !!(spi->mode & SPI_LSB_FIRST));
	}

	/* use spi->controller data for CS (same strategy as spi_gpio) */
	gpio_set_value((unsigned)spi->controller_data, value);

	if (is_on == BITBANG_CS_INACTIVE) {
		if (test_and_clear_bit(0, &p->flags)) {
			clk_disable(p->clk);
			pm_runtime_put(&p->pdev->dev);
		}
	}
}

static int sh_msiof_spi_txrx_once(struct sh_msiof_spi_priv *p,
				  void (*tx_fifo)(struct sh_msiof_spi_priv *,
						  const void *, int, int),
				  void (*rx_fifo)(struct sh_msiof_spi_priv *,
						  void *, int, int),
				  const void *tx_buf, void *rx_buf,
				  int words, int bits)
{
	int fifo_shift;
	int ret;

	/* limit maximum word transfer to rx/tx fifo size */
	if (tx_buf)
		words = min_t(int, words, p->tx_fifo_size);
	if (rx_buf)
		words = min_t(int, words, p->rx_fifo_size);

	/* the fifo contents need shifting */
	fifo_shift = 32 - bits;

	/* setup msiof transfer mode registers */
	sh_msiof_spi_set_mode_regs(p, tx_buf, rx_buf, bits, words);

	/* write tx fifo */
	if (tx_buf)
		tx_fifo(p, tx_buf, words, fifo_shift);

	/* setup clock and rx/tx signals */
	ret = sh_msiof_modify_ctr_wait(p, 0, CTR_TSCKE);
	if (rx_buf)
		ret = ret ? ret : sh_msiof_modify_ctr_wait(p, 0, CTR_RXE);
	ret = ret ? ret : sh_msiof_modify_ctr_wait(p, 0, CTR_TXE);

	/* start by setting frame bit */
	INIT_COMPLETION(p->done);
	ret = ret ? ret : sh_msiof_modify_ctr_wait(p, 0, CTR_TFSE);
	if (ret) {
		dev_err(&p->pdev->dev, "failed to start hardware\n");
		goto err;
	}

	/* wait for tx fifo to be emptied / rx fifo to be filled */
	wait_for_completion(&p->done);

	/* read rx fifo */
	if (rx_buf)
		rx_fifo(p, rx_buf, words, fifo_shift);

	/* clear status bits */
	sh_msiof_reset_str(p);

	/* shut down frame, tx/tx and clock signals */
	ret = sh_msiof_modify_ctr_wait(p, CTR_TFSE, 0);
	ret = ret ? ret : sh_msiof_modify_ctr_wait(p, CTR_TXE, 0);
	if (rx_buf)
		ret = ret ? ret : sh_msiof_modify_ctr_wait(p, CTR_RXE, 0);
	ret = ret ? ret : sh_msiof_modify_ctr_wait(p, CTR_TSCKE, 0);
	if (ret) {
		dev_err(&p->pdev->dev, "failed to shut down hardware\n");
		goto err;
	}

	return words;

 err:
	sh_msiof_write(p, IER, 0);
	return ret;
}

static int sh_msiof_spi_txrx(struct spi_device *spi, struct spi_transfer *t)
{
	struct sh_msiof_spi_priv *p = spi_master_get_devdata(spi->master);
	void (*tx_fifo)(struct sh_msiof_spi_priv *, const void *, int, int);
	void (*rx_fifo)(struct sh_msiof_spi_priv *, void *, int, int);
	int bits;
	int bytes_per_word;
	int bytes_done;
	int words;
	int n;

	bits = sh_msiof_spi_bits(spi, t);

	/* setup bytes per word and fifo read/write functions */
	if (bits <= 8) {
		bytes_per_word = 1;
		tx_fifo = sh_msiof_spi_write_fifo_8;
		rx_fifo = sh_msiof_spi_read_fifo_8;
	} else if (bits <= 16) {
		bytes_per_word = 2;
		if ((unsigned long)t->tx_buf & 0x01)
			tx_fifo = sh_msiof_spi_write_fifo_16u;
		else
			tx_fifo = sh_msiof_spi_write_fifo_16;

		if ((unsigned long)t->rx_buf & 0x01)
			rx_fifo = sh_msiof_spi_read_fifo_16u;
		else
			rx_fifo = sh_msiof_spi_read_fifo_16;
	} else {
		bytes_per_word = 4;
		if ((unsigned long)t->tx_buf & 0x03)
			tx_fifo = sh_msiof_spi_write_fifo_32u;
		else
			tx_fifo = sh_msiof_spi_write_fifo_32;

		if ((unsigned long)t->rx_buf & 0x03)
			rx_fifo = sh_msiof_spi_read_fifo_32u;
		else
			rx_fifo = sh_msiof_spi_read_fifo_32;
	}

	/* setup clocks (clock already enabled in chipselect()) */
	sh_msiof_spi_set_clk_regs(p, clk_get_rate(p->clk),
				  sh_msiof_spi_hz(spi, t));

	/* transfer in fifo sized chunks */
	words = t->len / bytes_per_word;
	bytes_done = 0;

	while (bytes_done < t->len) {
		n = sh_msiof_spi_txrx_once(p, tx_fifo, rx_fifo,
					   t->tx_buf + bytes_done,
					   t->rx_buf + bytes_done,
					   words, bits);
		if (n < 0)
			break;

		bytes_done += n * bytes_per_word;
		words -= n;
	}

	return bytes_done;
}

static u32 sh_msiof_spi_txrx_word(struct spi_device *spi, unsigned nsecs,
				  u32 word, u8 bits)
{
	BUG(); /* unused but needed by bitbang code */
	return 0;
}

static int sh_msiof_spi_probe(struct platform_device *pdev)
{
	struct resource	*r;
	struct spi_master *master;
	struct sh_msiof_spi_priv *p;
	char clk_name[16];
	int i;
	int ret;

	master = spi_alloc_master(&pdev->dev, sizeof(struct sh_msiof_spi_priv));
	if (master == NULL) {
		dev_err(&pdev->dev, "failed to allocate spi master\n");
		ret = -ENOMEM;
		goto err0;
	}

	p = spi_master_get_devdata(master);

	platform_set_drvdata(pdev, p);
	p->info = pdev->dev.platform_data;
	init_completion(&p->done);

	snprintf(clk_name, sizeof(clk_name), "msiof%d", pdev->id);
	p->clk = clk_get(&pdev->dev, clk_name);
	if (IS_ERR(p->clk)) {
		dev_err(&pdev->dev, "cannot get clock \"%s\"\n", clk_name);
		ret = PTR_ERR(p->clk);
		goto err1;
	}

	r = platform_get_resource(pdev, IORESOURCE_MEM, 0);
	i = platform_get_irq(pdev, 0);
	if (!r || i < 0) {
		dev_err(&pdev->dev, "cannot get platform resources\n");
		ret = -ENOENT;
		goto err2;
	}
	p->mapbase = ioremap_nocache(r->start, resource_size(r));
	if (!p->mapbase) {
		dev_err(&pdev->dev, "unable to ioremap\n");
		ret = -ENXIO;
		goto err2;
	}

	ret = request_irq(i, sh_msiof_spi_irq, IRQF_DISABLED,
			  dev_name(&pdev->dev), p);
	if (ret) {
		dev_err(&pdev->dev, "unable to request irq\n");
		goto err3;
	}

	p->pdev = pdev;
	pm_runtime_enable(&pdev->dev);

	/* The standard version of MSIOF use 64 word FIFOs */
	p->tx_fifo_size = 64;
	p->rx_fifo_size = 64;

	/* Platform data may override FIFO sizes */
	if (p->info->tx_fifo_override)
		p->tx_fifo_size = p->info->tx_fifo_override;
	if (p->info->rx_fifo_override)
		p->rx_fifo_size = p->info->rx_fifo_override;

	/* init master and bitbang code */
	master->mode_bits = SPI_CPOL | SPI_CPHA | SPI_CS_HIGH;
	master->mode_bits |= SPI_LSB_FIRST | SPI_3WIRE;
	master->flags = 0;
	master->bus_num = pdev->id;
	master->num_chipselect = p->info->num_chipselect;
	master->setup = spi_bitbang_setup;
	master->cleanup = spi_bitbang_cleanup;

	p->bitbang.master = master;
	p->bitbang.chipselect = sh_msiof_spi_chipselect;
	p->bitbang.setup_transfer = sh_msiof_spi_setup_transfer;
	p->bitbang.txrx_bufs = sh_msiof_spi_txrx;
	p->bitbang.txrx_word[SPI_MODE_0] = sh_msiof_spi_txrx_word;
	p->bitbang.txrx_word[SPI_MODE_1] = sh_msiof_spi_txrx_word;
	p->bitbang.txrx_word[SPI_MODE_2] = sh_msiof_spi_txrx_word;
	p->bitbang.txrx_word[SPI_MODE_3] = sh_msiof_spi_txrx_word;

	ret = spi_bitbang_start(&p->bitbang);
	if (ret == 0)
		return 0;

	pm_runtime_disable(&pdev->dev);
 err3:
	iounmap(p->mapbase);
 err2:
	clk_put(p->clk);
 err1:
	spi_master_put(master);
 err0:
	return ret;
}

static int sh_msiof_spi_remove(struct platform_device *pdev)
{
	struct sh_msiof_spi_priv *p = platform_get_drvdata(pdev);
	int ret;

	ret = spi_bitbang_stop(&p->bitbang);
	if (!ret) {
		pm_runtime_disable(&pdev->dev);
		free_irq(platform_get_irq(pdev, 0), sh_msiof_spi_irq);
		iounmap(p->mapbase);
		clk_put(p->clk);
		spi_master_put(p->bitbang.master);
	}
	return ret;
}

static int sh_msiof_spi_runtime_nop(struct device *dev)
{
	/* Runtime PM callback shared between ->runtime_suspend()
	 * and ->runtime_resume(). Simply returns success.
	 *
	 * This driver re-initializes all registers after
	 * pm_runtime_get_sync() anyway so there is no need
	 * to save and restore registers here.
	 */
	return 0;
}

static struct dev_pm_ops sh_msiof_spi_dev_pm_ops = {
	.runtime_suspend = sh_msiof_spi_runtime_nop,
	.runtime_resume = sh_msiof_spi_runtime_nop,
};

static struct platform_driver sh_msiof_spi_drv = {
	.probe		= sh_msiof_spi_probe,
	.remove		= sh_msiof_spi_remove,
	.driver		= {
		.name		= "spi_sh_msiof",
		.owner		= THIS_MODULE,
		.pm		= &sh_msiof_spi_dev_pm_ops,
	},
};

static int __init sh_msiof_spi_init(void)
{
	return platform_driver_register(&sh_msiof_spi_drv);
}
module_init(sh_msiof_spi_init);

static void __exit sh_msiof_spi_exit(void)
{
	platform_driver_unregister(&sh_msiof_spi_drv);
}
module_exit(sh_msiof_spi_exit);

MODULE_DESCRIPTION("SuperH MSIOF SPI Master Interface Driver");
MODULE_AUTHOR("Magnus Damm");
MODULE_LICENSE("GPL v2");
MODULE_ALIAS("platform:spi_sh_msiof");
OpenPOWER on IntegriCloud