aboutsummaryrefslogtreecommitdiff
path: root/sound/soc/davinci/davinci-i2s.c
blob: 4aad7ecc90a24d974ab86dec2c9f97caa9cf9bb9 (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
/*
 * ALSA SoC I2S (McBSP) Audio Layer for TI DAVINCI processor
 *
 * Author:      Vladimir Barinov, <vbarinov@embeddedalley.com>
 * Copyright:   (C) 2007 MontaVista Software, Inc., <source@mvista.com>
 *
 * 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/init.h>
#include <linux/module.h>
#include <linux/device.h>
#include <linux/delay.h>
#include <linux/io.h>
#include <linux/clk.h>

#include <sound/core.h>
#include <sound/pcm.h>
#include <sound/pcm_params.h>
#include <sound/initval.h>
#include <sound/soc.h>

#include <mach/asp.h>

#include "davinci-pcm.h"


/*
 * NOTE:  terminology here is confusing.
 *
 *  - This driver supports the "Audio Serial Port" (ASP),
 *    found on dm6446, dm355, and other DaVinci chips.
 *
 *  - But it labels it a "Multi-channel Buffered Serial Port"
 *    (McBSP) as on older chips like the dm642 ... which was
 *    backward-compatible, possibly explaining that confusion.
 *
 *  - OMAP chips have a controller called McBSP, which is
 *    incompatible with the DaVinci flavor of McBSP.
 *
 *  - Newer DaVinci chips have a controller called McASP,
 *    incompatible with ASP and with either McBSP.
 *
 * In short:  this uses ASP to implement I2S, not McBSP.
 * And it won't be the only DaVinci implemention of I2S.
 */
#define DAVINCI_MCBSP_DRR_REG	0x00
#define DAVINCI_MCBSP_DXR_REG	0x04
#define DAVINCI_MCBSP_SPCR_REG	0x08
#define DAVINCI_MCBSP_RCR_REG	0x0c
#define DAVINCI_MCBSP_XCR_REG	0x10
#define DAVINCI_MCBSP_SRGR_REG	0x14
#define DAVINCI_MCBSP_PCR_REG	0x24

#define DAVINCI_MCBSP_SPCR_RRST		(1 << 0)
#define DAVINCI_MCBSP_SPCR_RINTM(v)	((v) << 4)
#define DAVINCI_MCBSP_SPCR_XRST		(1 << 16)
#define DAVINCI_MCBSP_SPCR_XINTM(v)	((v) << 20)
#define DAVINCI_MCBSP_SPCR_GRST		(1 << 22)
#define DAVINCI_MCBSP_SPCR_FRST		(1 << 23)
#define DAVINCI_MCBSP_SPCR_FREE		(1 << 25)

#define DAVINCI_MCBSP_RCR_RWDLEN1(v)	((v) << 5)
#define DAVINCI_MCBSP_RCR_RFRLEN1(v)	((v) << 8)
#define DAVINCI_MCBSP_RCR_RDATDLY(v)	((v) << 16)
#define DAVINCI_MCBSP_RCR_RFIG		(1 << 18)
#define DAVINCI_MCBSP_RCR_RWDLEN2(v)	((v) << 21)

#define DAVINCI_MCBSP_XCR_XWDLEN1(v)	((v) << 5)
#define DAVINCI_MCBSP_XCR_XFRLEN1(v)	((v) << 8)
#define DAVINCI_MCBSP_XCR_XDATDLY(v)	((v) << 16)
#define DAVINCI_MCBSP_XCR_XFIG		(1 << 18)
#define DAVINCI_MCBSP_XCR_XWDLEN2(v)	((v) << 21)

#define DAVINCI_MCBSP_SRGR_FWID(v)	((v) << 8)
#define DAVINCI_MCBSP_SRGR_FPER(v)	((v) << 16)
#define DAVINCI_MCBSP_SRGR_FSGM		(1 << 28)

#define DAVINCI_MCBSP_PCR_CLKRP		(1 << 0)
#define DAVINCI_MCBSP_PCR_CLKXP		(1 << 1)
#define DAVINCI_MCBSP_PCR_FSRP		(1 << 2)
#define DAVINCI_MCBSP_PCR_FSXP		(1 << 3)
#define DAVINCI_MCBSP_PCR_SCLKME	(1 << 7)
#define DAVINCI_MCBSP_PCR_CLKRM		(1 << 8)
#define DAVINCI_MCBSP_PCR_CLKXM		(1 << 9)
#define DAVINCI_MCBSP_PCR_FSRM		(1 << 10)
#define DAVINCI_MCBSP_PCR_FSXM		(1 << 11)

enum {
	DAVINCI_MCBSP_WORD_8 = 0,
	DAVINCI_MCBSP_WORD_12,
	DAVINCI_MCBSP_WORD_16,
	DAVINCI_MCBSP_WORD_20,
	DAVINCI_MCBSP_WORD_24,
	DAVINCI_MCBSP_WORD_32,
};

static const unsigned char data_type[SNDRV_PCM_FORMAT_S32_LE + 1] = {
	[SNDRV_PCM_FORMAT_S8]		= 1,
	[SNDRV_PCM_FORMAT_S16_LE]	= 2,
	[SNDRV_PCM_FORMAT_S32_LE]	= 4,
};

static const unsigned char asp_word_length[SNDRV_PCM_FORMAT_S32_LE + 1] = {
	[SNDRV_PCM_FORMAT_S8]		= DAVINCI_MCBSP_WORD_8,
	[SNDRV_PCM_FORMAT_S16_LE]	= DAVINCI_MCBSP_WORD_16,
	[SNDRV_PCM_FORMAT_S32_LE]	= DAVINCI_MCBSP_WORD_32,
};

static const unsigned char double_fmt[SNDRV_PCM_FORMAT_S32_LE + 1] = {
	[SNDRV_PCM_FORMAT_S8]		= SNDRV_PCM_FORMAT_S16_LE,
	[SNDRV_PCM_FORMAT_S16_LE]	= SNDRV_PCM_FORMAT_S32_LE,
};

struct davinci_mcbsp_dev {
	struct davinci_pcm_dma_params	dma_params[2];
	void __iomem			*base;
#define MOD_DSP_A	0
#define MOD_DSP_B	1
	int				mode;
	u32				pcr;
	struct clk			*clk;
	/*
	 * Combining both channels into 1 element will at least double the
	 * amount of time between servicing the dma channel, increase
	 * effiency, and reduce the chance of overrun/underrun. But,
	 * it will result in the left & right channels being swapped.
	 *
	 * If relabeling the left and right channels is not possible,
	 * you may want to let the codec know to swap them back.
	 *
	 * It may allow x10 the amount of time to service dma requests,
	 * if the codec is master and is using an unnecessarily fast bit clock
	 * (ie. tlvaic23b), independent of the sample rate. So, having an
	 * entire frame at once means it can be serviced at the sample rate
	 * instead of the bit clock rate.
	 *
	 * In the now unlikely case that an underrun still
	 * occurs, both the left and right samples will be repeated
	 * so that no pops are heard, and the left and right channels
	 * won't end up being swapped because of the underrun.
	 */
	unsigned enable_channel_combine:1;
};

static inline void davinci_mcbsp_write_reg(struct davinci_mcbsp_dev *dev,
					   int reg, u32 val)
{
	__raw_writel(val, dev->base + reg);
}

static inline u32 davinci_mcbsp_read_reg(struct davinci_mcbsp_dev *dev, int reg)
{
	return __raw_readl(dev->base + reg);
}

static void toggle_clock(struct davinci_mcbsp_dev *dev, int playback)
{
	u32 m = playback ? DAVINCI_MCBSP_PCR_CLKXP : DAVINCI_MCBSP_PCR_CLKRP;
	/* The clock needs to toggle to complete reset.
	 * So, fake it by toggling the clk polarity.
	 */
	davinci_mcbsp_write_reg(dev, DAVINCI_MCBSP_PCR_REG, dev->pcr ^ m);
	davinci_mcbsp_write_reg(dev, DAVINCI_MCBSP_PCR_REG, dev->pcr);
}

static void davinci_mcbsp_start(struct davinci_mcbsp_dev *dev,
		struct snd_pcm_substream *substream)
{
	struct snd_soc_pcm_runtime *rtd = substream->private_data;
	struct snd_soc_device *socdev = rtd->socdev;
	struct snd_soc_platform *platform = socdev->card->platform;
	int playback = (substream->stream == SNDRV_PCM_STREAM_PLAYBACK);
	u32 spcr;
	u32 mask = playback ? DAVINCI_MCBSP_SPCR_XRST : DAVINCI_MCBSP_SPCR_RRST;
	spcr = davinci_mcbsp_read_reg(dev, DAVINCI_MCBSP_SPCR_REG);
	if (spcr & mask) {
		/* start off disabled */
		davinci_mcbsp_write_reg(dev, DAVINCI_MCBSP_SPCR_REG,
				spcr & ~mask);
		toggle_clock(dev, playback);
	}
	if (dev->pcr & (DAVINCI_MCBSP_PCR_FSXM | DAVINCI_MCBSP_PCR_FSRM |
			DAVINCI_MCBSP_PCR_CLKXM | DAVINCI_MCBSP_PCR_CLKRM)) {
		/* Start the sample generator */
		spcr |= DAVINCI_MCBSP_SPCR_GRST;
		davinci_mcbsp_write_reg(dev, DAVINCI_MCBSP_SPCR_REG, spcr);
	}

	if (playback) {
		/* Stop the DMA to avoid data loss */
		/* while the transmitter is out of reset to handle XSYNCERR */
		if (platform->pcm_ops->trigger) {
			int ret = platform->pcm_ops->trigger(substream,
				SNDRV_PCM_TRIGGER_STOP);
			if (ret < 0)
				printk(KERN_DEBUG "Playback DMA stop failed\n");
		}

		/* Enable the transmitter */
		spcr = davinci_mcbsp_read_reg(dev, DAVINCI_MCBSP_SPCR_REG);
		spcr |= DAVINCI_MCBSP_SPCR_XRST;
		davinci_mcbsp_write_reg(dev, DAVINCI_MCBSP_SPCR_REG, spcr);

		/* wait for any unexpected frame sync error to occur */
		udelay(100);

		/* Disable the transmitter to clear any outstanding XSYNCERR */
		spcr = davinci_mcbsp_read_reg(dev, DAVINCI_MCBSP_SPCR_REG);
		spcr &= ~DAVINCI_MCBSP_SPCR_XRST;
		davinci_mcbsp_write_reg(dev, DAVINCI_MCBSP_SPCR_REG, spcr);
		toggle_clock(dev, playback);

		/* Restart the DMA */
		if (platform->pcm_ops->trigger) {
			int ret = platform->pcm_ops->trigger(substream,
				SNDRV_PCM_TRIGGER_START);
			if (ret < 0)
				printk(KERN_DEBUG "Playback DMA start failed\n");
		}
	}

	/* Enable transmitter or receiver */
	spcr = davinci_mcbsp_read_reg(dev, DAVINCI_MCBSP_SPCR_REG);
	spcr |= mask;

	if (dev->pcr & (DAVINCI_MCBSP_PCR_FSXM | DAVINCI_MCBSP_PCR_FSRM)) {
		/* Start frame sync */
		spcr |= DAVINCI_MCBSP_SPCR_FRST;
	}
	davinci_mcbsp_write_reg(dev, DAVINCI_MCBSP_SPCR_REG, spcr);
}

static void davinci_mcbsp_stop(struct davinci_mcbsp_dev *dev, int playback)
{
	u32 spcr;

	/* Reset transmitter/receiver and sample rate/frame sync generators */
	spcr = davinci_mcbsp_read_reg(dev, DAVINCI_MCBSP_SPCR_REG);
	spcr &= ~(DAVINCI_MCBSP_SPCR_GRST | DAVINCI_MCBSP_SPCR_FRST);
	spcr &= playback ? ~DAVINCI_MCBSP_SPCR_XRST : ~DAVINCI_MCBSP_SPCR_RRST;
	davinci_mcbsp_write_reg(dev, DAVINCI_MCBSP_SPCR_REG, spcr);
	toggle_clock(dev, playback);
}

#define DEFAULT_BITPERSAMPLE	16

static int davinci_i2s_set_dai_fmt(struct snd_soc_dai *cpu_dai,
				   unsigned int fmt)
{
	struct davinci_mcbsp_dev *dev = cpu_dai->private_data;
	unsigned int pcr;
	unsigned int srgr;
	srgr = DAVINCI_MCBSP_SRGR_FSGM |
		DAVINCI_MCBSP_SRGR_FPER(DEFAULT_BITPERSAMPLE * 2 - 1) |
		DAVINCI_MCBSP_SRGR_FWID(DEFAULT_BITPERSAMPLE - 1);

	/* set master/slave audio interface */
	switch (fmt & SND_SOC_DAIFMT_MASTER_MASK) {
	case SND_SOC_DAIFMT_CBS_CFS:
		/* cpu is master */
		pcr = DAVINCI_MCBSP_PCR_FSXM |
			DAVINCI_MCBSP_PCR_FSRM |
			DAVINCI_MCBSP_PCR_CLKXM |
			DAVINCI_MCBSP_PCR_CLKRM;
		break;
	case SND_SOC_DAIFMT_CBM_CFS:
		/* McBSP CLKR pin is the input for the Sample Rate Generator.
		 * McBSP FSR and FSX are driven by the Sample Rate Generator. */
		pcr = DAVINCI_MCBSP_PCR_SCLKME |
			DAVINCI_MCBSP_PCR_FSXM |
			DAVINCI_MCBSP_PCR_FSRM;
		break;
	case SND_SOC_DAIFMT_CBM_CFM:
		/* codec is master */
		pcr = 0;
		break;
	default:
		printk(KERN_ERR "%s:bad master\n", __func__);
		return -EINVAL;
	}

	/* interface format */
	switch (fmt & SND_SOC_DAIFMT_FORMAT_MASK) {
	case SND_SOC_DAIFMT_I2S:
		/* Davinci doesn't support TRUE I2S, but some codecs will have
		 * the left and right channels contiguous. This allows
		 * dsp_a mode to be used with an inverted normal frame clk.
		 * If your codec is master and does not have contiguous
		 * channels, then you will have sound on only one channel.
		 * Try using a different mode, or codec as slave.
		 *
		 * The TLV320AIC33 is an example of a codec where this works.
		 * It has a variable bit clock frequency allowing it to have
		 * valid data on every bit clock.
		 *
		 * The TLV320AIC23 is an example of a codec where this does not
		 * work. It has a fixed bit clock frequency with progressively
		 * more empty bit clock slots between channels as the sample
		 * rate is lowered.
		 */
		fmt ^= SND_SOC_DAIFMT_NB_IF;
	case SND_SOC_DAIFMT_DSP_A:
		dev->mode = MOD_DSP_A;
		break;
	case SND_SOC_DAIFMT_DSP_B:
		dev->mode = MOD_DSP_B;
		break;
	default:
		printk(KERN_ERR "%s:bad format\n", __func__);
		return -EINVAL;
	}

	switch (fmt & SND_SOC_DAIFMT_INV_MASK) {
	case SND_SOC_DAIFMT_NB_NF:
		/* CLKRP Receive clock polarity,
		 *	1 - sampled on rising edge of CLKR
		 *	valid on rising edge
		 * CLKXP Transmit clock polarity,
		 *	1 - clocked on falling edge of CLKX
		 *	valid on rising edge
		 * FSRP  Receive frame sync pol, 0 - active high
		 * FSXP  Transmit frame sync pol, 0 - active high
		 */
		pcr |= (DAVINCI_MCBSP_PCR_CLKXP | DAVINCI_MCBSP_PCR_CLKRP);
		break;
	case SND_SOC_DAIFMT_IB_IF:
		/* CLKRP Receive clock polarity,
		 *	0 - sampled on falling edge of CLKR
		 *	valid on falling edge
		 * CLKXP Transmit clock polarity,
		 *	0 - clocked on rising edge of CLKX
		 *	valid on falling edge
		 * FSRP  Receive frame sync pol, 1 - active low
		 * FSXP  Transmit frame sync pol, 1 - active low
		 */
		pcr |= (DAVINCI_MCBSP_PCR_FSXP | DAVINCI_MCBSP_PCR_FSRP);
		break;
	case SND_SOC_DAIFMT_NB_IF:
		/* CLKRP Receive clock polarity,
		 *	1 - sampled on rising edge of CLKR
		 *	valid on rising edge
		 * CLKXP Transmit clock polarity,
		 *	1 - clocked on falling edge of CLKX
		 *	valid on rising edge
		 * FSRP  Receive frame sync pol, 1 - active low
		 * FSXP  Transmit frame sync pol, 1 - active low
		 */
		pcr |= (DAVINCI_MCBSP_PCR_CLKXP | DAVINCI_MCBSP_PCR_CLKRP |
			DAVINCI_MCBSP_PCR_FSXP | DAVINCI_MCBSP_PCR_FSRP);
		break;
	case SND_SOC_DAIFMT_IB_NF:
		/* CLKRP Receive clock polarity,
		 *	0 - sampled on falling edge of CLKR
		 *	valid on falling edge
		 * CLKXP Transmit clock polarity,
		 *	0 - clocked on rising edge of CLKX
		 *	valid on falling edge
		 * FSRP  Receive frame sync pol, 0 - active high
		 * FSXP  Transmit frame sync pol, 0 - active high
		 */
		break;
	default:
		return -EINVAL;
	}
	davinci_mcbsp_write_reg(dev, DAVINCI_MCBSP_SRGR_REG, srgr);
	dev->pcr = pcr;
	davinci_mcbsp_write_reg(dev, DAVINCI_MCBSP_PCR_REG, pcr);
	return 0;
}

static int davinci_i2s_hw_params(struct snd_pcm_substream *substream,
				 struct snd_pcm_hw_params *params,
				 struct snd_soc_dai *dai)
{
	struct davinci_mcbsp_dev *dev = dai->private_data;
	struct davinci_pcm_dma_params *dma_params =
					&dev->dma_params[substream->stream];
	struct snd_interval *i = NULL;
	int mcbsp_word_length;
	unsigned int rcr, xcr, srgr;
	u32 spcr;
	snd_pcm_format_t fmt;
	unsigned element_cnt = 1;

	/* general line settings */
	spcr = davinci_mcbsp_read_reg(dev, DAVINCI_MCBSP_SPCR_REG);
	if (substream->stream == SNDRV_PCM_STREAM_CAPTURE) {
		spcr |= DAVINCI_MCBSP_SPCR_RINTM(3) | DAVINCI_MCBSP_SPCR_FREE;
		davinci_mcbsp_write_reg(dev, DAVINCI_MCBSP_SPCR_REG, spcr);
	} else {
		spcr |= DAVINCI_MCBSP_SPCR_XINTM(3) | DAVINCI_MCBSP_SPCR_FREE;
		davinci_mcbsp_write_reg(dev, DAVINCI_MCBSP_SPCR_REG, spcr);
	}

	i = hw_param_interval(params, SNDRV_PCM_HW_PARAM_SAMPLE_BITS);
	srgr = DAVINCI_MCBSP_SRGR_FSGM;
	srgr |= DAVINCI_MCBSP_SRGR_FWID(snd_interval_value(i) - 1);

	i = hw_param_interval(params, SNDRV_PCM_HW_PARAM_FRAME_BITS);
	srgr |= DAVINCI_MCBSP_SRGR_FPER(snd_interval_value(i) - 1);
	davinci_mcbsp_write_reg(dev, DAVINCI_MCBSP_SRGR_REG, srgr);

	rcr = DAVINCI_MCBSP_RCR_RFIG;
	xcr = DAVINCI_MCBSP_XCR_XFIG;
	if (dev->mode == MOD_DSP_B) {
		rcr |= DAVINCI_MCBSP_RCR_RDATDLY(0);
		xcr |= DAVINCI_MCBSP_XCR_XDATDLY(0);
	} else {
		rcr |= DAVINCI_MCBSP_RCR_RDATDLY(1);
		xcr |= DAVINCI_MCBSP_XCR_XDATDLY(1);
	}
	/* Determine xfer data type */
	fmt = params_format(params);
	if ((fmt > SNDRV_PCM_FORMAT_S32_LE) || !data_type[fmt]) {
		printk(KERN_WARNING "davinci-i2s: unsupported PCM format\n");
		return -EINVAL;
	}

	if (params_channels(params) == 2) {
		element_cnt = 2;
		if (double_fmt[fmt] && dev->enable_channel_combine) {
			element_cnt = 1;
			fmt = double_fmt[fmt];
		}
	}
	dma_params->acnt = dma_params->data_type = data_type[fmt];
	dma_params->fifo_level = 0;
	mcbsp_word_length = asp_word_length[fmt];
	rcr |= DAVINCI_MCBSP_RCR_RFRLEN1(element_cnt - 1);
	xcr |= DAVINCI_MCBSP_XCR_XFRLEN1(element_cnt - 1);

	rcr |= DAVINCI_MCBSP_RCR_RWDLEN1(mcbsp_word_length) |
		DAVINCI_MCBSP_RCR_RWDLEN2(mcbsp_word_length);
	xcr |= DAVINCI_MCBSP_XCR_XWDLEN1(mcbsp_word_length) |
		DAVINCI_MCBSP_XCR_XWDLEN2(mcbsp_word_length);

	if (substream->stream == SNDRV_PCM_STREAM_PLAYBACK)
		davinci_mcbsp_write_reg(dev, DAVINCI_MCBSP_XCR_REG, xcr);
	else
		davinci_mcbsp_write_reg(dev, DAVINCI_MCBSP_RCR_REG, rcr);
	return 0;
}

static int davinci_i2s_prepare(struct snd_pcm_substream *substream,
		struct snd_soc_dai *dai)
{
	struct davinci_mcbsp_dev *dev = dai->private_data;
	int playback = (substream->stream == SNDRV_PCM_STREAM_PLAYBACK);
	davinci_mcbsp_stop(dev, playback);
	if ((dev->pcr & DAVINCI_MCBSP_PCR_FSXM) == 0) {
		/* codec is master */
		davinci_mcbsp_start(dev, substream);
	}
	return 0;
}

static int davinci_i2s_trigger(struct snd_pcm_substream *substream, int cmd,
			       struct snd_soc_dai *dai)
{
	struct davinci_mcbsp_dev *dev = dai->private_data;
	int ret = 0;
	int playback = (substream->stream == SNDRV_PCM_STREAM_PLAYBACK);
	if ((dev->pcr & DAVINCI_MCBSP_PCR_FSXM) == 0)
		return 0;	/* return if codec is master */

	switch (cmd) {
	case SNDRV_PCM_TRIGGER_START:
	case SNDRV_PCM_TRIGGER_RESUME:
	case SNDRV_PCM_TRIGGER_PAUSE_RELEASE:
		davinci_mcbsp_start(dev, substream);
		break;
	case SNDRV_PCM_TRIGGER_STOP:
	case SNDRV_PCM_TRIGGER_SUSPEND:
	case SNDRV_PCM_TRIGGER_PAUSE_PUSH:
		davinci_mcbsp_stop(dev, playback);
		break;
	default:
		ret = -EINVAL;
	}
	return ret;
}

static void davinci_i2s_shutdown(struct snd_pcm_substream *substream,
		struct snd_soc_dai *dai)
{
	struct davinci_mcbsp_dev *dev = dai->private_data;
	int playback = (substream->stream == SNDRV_PCM_STREAM_PLAYBACK);
	davinci_mcbsp_stop(dev, playback);
}

#define DAVINCI_I2S_RATES	SNDRV_PCM_RATE_8000_96000

static struct snd_soc_dai_ops davinci_i2s_dai_ops = {
	.shutdown	= davinci_i2s_shutdown,
	.prepare	= davinci_i2s_prepare,
	.trigger	= davinci_i2s_trigger,
	.hw_params	= davinci_i2s_hw_params,
	.set_fmt	= davinci_i2s_set_dai_fmt,

};

struct snd_soc_dai davinci_i2s_dai = {
	.name = "davinci-i2s",
	.id = 0,
	.playback = {
		.channels_min = 2,
		.channels_max = 2,
		.rates = DAVINCI_I2S_RATES,
		.formats = SNDRV_PCM_FMTBIT_S16_LE,},
	.capture = {
		.channels_min = 2,
		.channels_max = 2,
		.rates = DAVINCI_I2S_RATES,
		.formats = SNDRV_PCM_FMTBIT_S16_LE,},
	.ops = &davinci_i2s_dai_ops,

};
EXPORT_SYMBOL_GPL(davinci_i2s_dai);

static int davinci_i2s_probe(struct platform_device *pdev)
{
	struct snd_platform_data *pdata = pdev->dev.platform_data;
	struct davinci_mcbsp_dev *dev;
	struct resource *mem, *ioarea, *res;
	int ret;

	mem = platform_get_resource(pdev, IORESOURCE_MEM, 0);
	if (!mem) {
		dev_err(&pdev->dev, "no mem resource?\n");
		return -ENODEV;
	}

	ioarea = request_mem_region(mem->start, (mem->end - mem->start) + 1,
				    pdev->name);
	if (!ioarea) {
		dev_err(&pdev->dev, "McBSP region already claimed\n");
		return -EBUSY;
	}

	dev = kzalloc(sizeof(struct davinci_mcbsp_dev), GFP_KERNEL);
	if (!dev) {
		ret = -ENOMEM;
		goto err_release_region;
	}
	if (pdata) {
		dev->enable_channel_combine = pdata->enable_channel_combine;
		dev->dma_params[SNDRV_PCM_STREAM_PLAYBACK].sram_size =
			pdata->sram_size_playback;
		dev->dma_params[SNDRV_PCM_STREAM_CAPTURE].sram_size =
			pdata->sram_size_capture;
	}
	dev->clk = clk_get(&pdev->dev, NULL);
	if (IS_ERR(dev->clk)) {
		ret = -ENODEV;
		goto err_free_mem;
	}
	clk_enable(dev->clk);

	dev->base = (void __iomem *)IO_ADDRESS(mem->start);

	dev->dma_params[SNDRV_PCM_STREAM_PLAYBACK].dma_addr =
	    (dma_addr_t)(io_v2p(dev->base) + DAVINCI_MCBSP_DXR_REG);

	dev->dma_params[SNDRV_PCM_STREAM_CAPTURE].dma_addr =
	    (dma_addr_t)(io_v2p(dev->base) + DAVINCI_MCBSP_DRR_REG);

	/* first TX, then RX */
	res = platform_get_resource(pdev, IORESOURCE_DMA, 0);
	if (!res) {
		dev_err(&pdev->dev, "no DMA resource\n");
		ret = -ENXIO;
		goto err_free_mem;
	}
	dev->dma_params[SNDRV_PCM_STREAM_PLAYBACK].channel = res->start;

	res = platform_get_resource(pdev, IORESOURCE_DMA, 1);
	if (!res) {
		dev_err(&pdev->dev, "no DMA resource\n");
		ret = -ENXIO;
		goto err_free_mem;
	}
	dev->dma_params[SNDRV_PCM_STREAM_CAPTURE].channel = res->start;

	davinci_i2s_dai.private_data = dev;
	davinci_i2s_dai.capture.dma_data = dev->dma_params;
	davinci_i2s_dai.playback.dma_data = dev->dma_params;
	ret = snd_soc_register_dai(&davinci_i2s_dai);
	if (ret != 0)
		goto err_free_mem;

	return 0;

err_free_mem:
	kfree(dev);
err_release_region:
	release_mem_region(mem->start, (mem->end - mem->start) + 1);

	return ret;
}

static int davinci_i2s_remove(struct platform_device *pdev)
{
	struct davinci_mcbsp_dev *dev = davinci_i2s_dai.private_data;
	struct resource *mem;

	snd_soc_unregister_dai(&davinci_i2s_dai);
	clk_disable(dev->clk);
	clk_put(dev->clk);
	dev->clk = NULL;
	kfree(dev);
	mem = platform_get_resource(pdev, IORESOURCE_MEM, 0);
	release_mem_region(mem->start, (mem->end - mem->start) + 1);

	return 0;
}

static struct platform_driver davinci_mcbsp_driver = {
	.probe		= davinci_i2s_probe,
	.remove		= davinci_i2s_remove,
	.driver		= {
		.name	= "davinci-asp",
		.owner	= THIS_MODULE,
	},
};

static int __init davinci_i2s_init(void)
{
	return platform_driver_register(&davinci_mcbsp_driver);
}
module_init(davinci_i2s_init);

static void __exit davinci_i2s_exit(void)
{
	platform_driver_unregister(&davinci_mcbsp_driver);
}
module_exit(davinci_i2s_exit);

MODULE_AUTHOR("Vladimir Barinov");
MODULE_DESCRIPTION("TI DAVINCI I2S (McBSP) SoC Interface");
MODULE_LICENSE("GPL");