summaryrefslogtreecommitdiffstats
path: root/sound/soc/codecs/cs4270.c
blob: 7507d468b2004a4d24b578ecc035705d71f9a343 (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
709
710
711
712
713
714
715
716
717
718
719
720
721
722
723
724
725
726
727
728
729
730
731
732
733
734
735
736
737
738
739
740
741
742
743
744
745
746
747
748
749
750
751
752
753
754
755
756
757
758
759
760
761
762
763
764
765
766
767
768
769
770
771
772
773
774
775
776
777
778
779
/*
 * CS4270 ALSA SoC (ASoC) codec driver
 *
 * Author: Timur Tabi <timur@freescale.com>
 *
 * Copyright 2007 Freescale Semiconductor, Inc.  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.
 *
 * This is an ASoC device driver for the Cirrus Logic CS4270 codec.
 *
 * Current features/limitations:
 *
 * 1) Software mode is supported.  Stand-alone mode is automatically
 *    selected if I2C is disabled or if a CS4270 is not found on the I2C
 *    bus.  However, stand-alone mode is only partially implemented because
 *    there is no mechanism yet for this driver and the machine driver to
 *    communicate the values of the M0, M1, MCLK1, and MCLK2 pins.
 * 2) Only I2C is supported, not SPI
 * 3) Only Master mode is supported, not Slave.
 * 4) The machine driver's 'startup' function must call
 *    cs4270_set_dai_sysclk() with the value of MCLK.
 * 5) Only I2S and left-justified modes are supported
 * 6) Power management is not supported
 * 7) The only supported control is volume and hardware mute (if enabled)
 */

#include <linux/module.h>
#include <linux/platform_device.h>
#include <sound/core.h>
#include <sound/soc.h>
#include <sound/initval.h>
#include <linux/i2c.h>

#include "cs4270.h"

/* If I2C is defined, then we support software mode.  However, if we're
   not compiled as module but I2C is, then we can't use I2C calls. */
#if defined(CONFIG_I2C) || (defined(CONFIG_I2C_MODULE) && defined(MODULE))
#define USE_I2C
#endif

/* Private data for the CS4270 */
struct cs4270_private {
	unsigned int mclk; /* Input frequency of the MCLK pin */
	unsigned int mode; /* The mode (I2S or left-justified) */
};

/*
 * The codec isn't really big-endian or little-endian, since the I2S
 * interface requires data to be sent serially with the MSbit first.
 * However, to support BE and LE I2S devices, we specify both here.  That
 * way, ALSA will always match the bit patterns.
 */
#define CS4270_FORMATS (SNDRV_PCM_FMTBIT_S8      | \
			SNDRV_PCM_FMTBIT_S16_LE  | SNDRV_PCM_FMTBIT_S16_BE  | \
			SNDRV_PCM_FMTBIT_S18_3LE | SNDRV_PCM_FMTBIT_S18_3BE | \
			SNDRV_PCM_FMTBIT_S20_3LE | SNDRV_PCM_FMTBIT_S20_3BE | \
			SNDRV_PCM_FMTBIT_S24_3LE | SNDRV_PCM_FMTBIT_S24_3BE | \
			SNDRV_PCM_FMTBIT_S24_LE  | SNDRV_PCM_FMTBIT_S24_BE)

#ifdef USE_I2C

/* CS4270 registers addresses */
#define CS4270_CHIPID	0x01	/* Chip ID */
#define CS4270_PWRCTL	0x02	/* Power Control */
#define CS4270_MODE	0x03	/* Mode Control */
#define CS4270_FORMAT	0x04	/* Serial Format, ADC/DAC Control */
#define CS4270_TRANS	0x05	/* Transition Control */
#define CS4270_MUTE	0x06	/* Mute Control */
#define CS4270_VOLA	0x07	/* DAC Channel A Volume Control */
#define CS4270_VOLB	0x08	/* DAC Channel B Volume Control */

#define CS4270_FIRSTREG	0x01
#define CS4270_LASTREG	0x08
#define CS4270_NUMREGS	(CS4270_LASTREG - CS4270_FIRSTREG + 1)

/* Bit masks for the CS4270 registers */
#define CS4270_CHIPID_ID	0xF0
#define CS4270_CHIPID_REV	0x0F
#define CS4270_PWRCTL_FREEZE	0x80
#define CS4270_PWRCTL_PDN_ADC	0x20
#define CS4270_PWRCTL_PDN_DAC	0x02
#define CS4270_PWRCTL_PDN	0x01
#define CS4270_MODE_SPEED_MASK	0x30
#define CS4270_MODE_1X		0x00
#define CS4270_MODE_2X		0x10
#define CS4270_MODE_4X		0x20
#define CS4270_MODE_SLAVE	0x30
#define CS4270_MODE_DIV_MASK	0x0E
#define CS4270_MODE_DIV1	0x00
#define CS4270_MODE_DIV15	0x02
#define CS4270_MODE_DIV2	0x04
#define CS4270_MODE_DIV3	0x06
#define CS4270_MODE_DIV4	0x08
#define CS4270_MODE_POPGUARD	0x01
#define CS4270_FORMAT_FREEZE_A	0x80
#define CS4270_FORMAT_FREEZE_B	0x40
#define CS4270_FORMAT_LOOPBACK	0x20
#define CS4270_FORMAT_DAC_MASK	0x18
#define CS4270_FORMAT_DAC_LJ	0x00
#define CS4270_FORMAT_DAC_I2S	0x08
#define CS4270_FORMAT_DAC_RJ16	0x18
#define CS4270_FORMAT_DAC_RJ24	0x10
#define CS4270_FORMAT_ADC_MASK	0x01
#define CS4270_FORMAT_ADC_LJ	0x00
#define CS4270_FORMAT_ADC_I2S	0x01
#define CS4270_TRANS_ONE_VOL	0x80
#define CS4270_TRANS_SOFT	0x40
#define CS4270_TRANS_ZERO	0x20
#define CS4270_TRANS_INV_ADC_A	0x08
#define CS4270_TRANS_INV_ADC_B	0x10
#define CS4270_TRANS_INV_DAC_A	0x02
#define CS4270_TRANS_INV_DAC_B	0x04
#define CS4270_TRANS_DEEMPH	0x01
#define CS4270_MUTE_AUTO	0x20
#define CS4270_MUTE_ADC_A	0x08
#define CS4270_MUTE_ADC_B	0x10
#define CS4270_MUTE_POLARITY	0x04
#define CS4270_MUTE_DAC_A	0x01
#define CS4270_MUTE_DAC_B	0x02

/*
 * Clock Ratio Selection for Master Mode with I2C enabled
 *
 * The data for this chart is taken from Table 5 of the CS4270 reference
 * manual.
 *
 * This table is used to determine how to program the Mode Control register.
 * It is also used by cs4270_set_dai_sysclk() to tell ALSA which sampling
 * rates the CS4270 currently supports.
 *
 * Each element in this array corresponds to the ratios in mclk_ratios[].
 * These two arrays need to be in sync.
 *
 * 'speed_mode' is the corresponding bit pattern to be written to the
 * MODE bits of the Mode Control Register
 *
 * 'mclk' is the corresponding bit pattern to be wirten to the MCLK bits of
 * the Mode Control Register.
 *
 * In situations where a single ratio is represented by multiple speed
 * modes, we favor the slowest speed.  E.g, for a ratio of 128, we pick
 * double-speed instead of quad-speed.  However, the CS4270 errata states
 * that Divide-By-1.5 can cause failures, so we avoid that mode where
 * possible.
 *
 * ERRATA: There is an errata for the CS4270 where divide-by-1.5 does not
 * work if VD = 3.3V.  If this effects you, select the
 * CONFIG_SND_SOC_CS4270_VD33_ERRATA Kconfig option, and the driver will
 * never select any sample rates that require divide-by-1.5.
 */
static struct {
	unsigned int ratio;
	u8 speed_mode;
	u8 mclk;
} cs4270_mode_ratios[] = {
	{64, CS4270_MODE_4X, CS4270_MODE_DIV1},
#ifndef CONFIG_SND_SOC_CS4270_VD33_ERRATA
	{96, CS4270_MODE_4X, CS4270_MODE_DIV15},
#endif
	{128, CS4270_MODE_2X, CS4270_MODE_DIV1},
	{192, CS4270_MODE_4X, CS4270_MODE_DIV3},
	{256, CS4270_MODE_1X, CS4270_MODE_DIV1},
	{384, CS4270_MODE_2X, CS4270_MODE_DIV3},
	{512, CS4270_MODE_1X, CS4270_MODE_DIV2},
	{768, CS4270_MODE_1X, CS4270_MODE_DIV3},
	{1024, CS4270_MODE_1X, CS4270_MODE_DIV4}
};

/* The number of MCLK/LRCK ratios supported by the CS4270 */
#define NUM_MCLK_RATIOS		ARRAY_SIZE(cs4270_mode_ratios)

/*
 * Determine the CS4270 samples rates.
 *
 * 'freq' is the input frequency to MCLK.  The other parameters are ignored.
 *
 * The value of MCLK is used to determine which sample rates are supported
 * by the CS4270.  The ratio of MCLK / Fs must be equal to one of nine
 * support values: 64, 96, 128, 192, 256, 384, 512, 768, and 1024.
 *
 * This function calculates the nine ratios and determines which ones match
 * a standard sample rate.  If there's a match, then it is added to the list
 * of support sample rates.
 *
 * This function must be called by the machine driver's 'startup' function,
 * otherwise the list of supported sample rates will not be available in
 * time for ALSA.
 *
 * Note that in stand-alone mode, the sample rate is determined by input
 * pins M0, M1, MDIV1, and MDIV2.  Also in stand-alone mode, divide-by-3
 * is not a programmable option.  However, divide-by-3 is not an available
 * option in stand-alone mode.  This cases two problems: a ratio of 768 is
 * not available (it requires divide-by-3) and B) ratios 192 and 384 can
 * only be selected with divide-by-1.5, but there is an errate that make
 * this selection difficult.
 *
 * In addition, there is no mechanism for communicating with the machine
 * driver what the input settings can be.  This would need to be implemented
 * for stand-alone mode to work.
 */
static int cs4270_set_dai_sysclk(struct snd_soc_dai *codec_dai,
				 int clk_id, unsigned int freq, int dir)
{
	struct snd_soc_codec *codec = codec_dai->codec;
	struct cs4270_private *cs4270 = codec->private_data;
	unsigned int rates = 0;
	unsigned int rate_min = -1;
	unsigned int rate_max = 0;
	unsigned int i;

	cs4270->mclk = freq;

	for (i = 0; i < NUM_MCLK_RATIOS; i++) {
		unsigned int rate = freq / cs4270_mode_ratios[i].ratio;
		rates |= snd_pcm_rate_to_rate_bit(rate);
		if (rate < rate_min)
			rate_min = rate;
		if (rate > rate_max)
			rate_max = rate;
	}
	/* FIXME: soc should support a rate list */
	rates &= ~SNDRV_PCM_RATE_KNOT;

	if (!rates) {
		printk(KERN_ERR "cs4270: could not find a valid sample rate\n");
		return -EINVAL;
	}

	codec_dai->playback.rates = rates;
	codec_dai->playback.rate_min = rate_min;
	codec_dai->playback.rate_max = rate_max;

	codec_dai->capture.rates = rates;
	codec_dai->capture.rate_min = rate_min;
	codec_dai->capture.rate_max = rate_max;

	return 0;
}

/*
 * Configure the codec for the selected audio format
 *
 * This function takes a bitmask of SND_SOC_DAIFMT_x bits and programs the
 * codec accordingly.
 *
 * Currently, this function only supports SND_SOC_DAIFMT_I2S and
 * SND_SOC_DAIFMT_LEFT_J.  The CS4270 codec also supports right-justified
 * data for playback only, but ASoC currently does not support different
 * formats for playback vs. record.
 */
static int cs4270_set_dai_fmt(struct snd_soc_dai *codec_dai,
			      unsigned int format)
{
	struct snd_soc_codec *codec = codec_dai->codec;
	struct cs4270_private *cs4270 = codec->private_data;
	int ret = 0;

	switch (format & SND_SOC_DAIFMT_FORMAT_MASK) {
	case SND_SOC_DAIFMT_I2S:
	case SND_SOC_DAIFMT_LEFT_J:
		cs4270->mode = format & SND_SOC_DAIFMT_FORMAT_MASK;
		break;
	default:
		printk(KERN_ERR "cs4270: invalid DAI format\n");
		ret = -EINVAL;
	}

	return ret;
}

/*
 * A list of addresses on which this CS4270 could use.  I2C addresses are
 * 7 bits.  For the CS4270, the upper four bits are always 1001, and the
 * lower three bits are determined via the AD2, AD1, and AD0 pins
 * (respectively).
 */
static const unsigned short normal_i2c[] = {
	0x48, 0x49, 0x4A, 0x4B, 0x4C, 0x4D, 0x4E, 0x4F, I2C_CLIENT_END
};
I2C_CLIENT_INSMOD;

/*
 * Pre-fill the CS4270 register cache.
 *
 * We use the auto-increment feature of the CS4270 to read all registers in
 * one shot.
 */
static int cs4270_fill_cache(struct snd_soc_codec *codec)
{
	u8 *cache = codec->reg_cache;
	struct i2c_client *i2c_client = codec->control_data;
	s32 length;

	length = i2c_smbus_read_i2c_block_data(i2c_client,
		CS4270_FIRSTREG | 0x80, CS4270_NUMREGS, cache);

	if (length != CS4270_NUMREGS) {
		printk(KERN_ERR "cs4270: I2C read failure, addr=0x%x\n",
		       i2c_client->addr);
		return -EIO;
	}

	return 0;
}

/*
 * Read from the CS4270 register cache.
 *
 * This CS4270 registers are cached to avoid excessive I2C I/O operations.
 * After the initial read to pre-fill the cache, the CS4270 never updates
 * the register values, so we won't have a cache coherncy problem.
 */
static unsigned int cs4270_read_reg_cache(struct snd_soc_codec *codec,
	unsigned int reg)
{
	u8 *cache = codec->reg_cache;

	if ((reg < CS4270_FIRSTREG) || (reg > CS4270_LASTREG))
		return -EIO;

	return cache[reg - CS4270_FIRSTREG];
}

/*
 * Write to a CS4270 register via the I2C bus.
 *
 * This function writes the given value to the given CS4270 register, and
 * also updates the register cache.
 *
 * Note that we don't use the hw_write function pointer of snd_soc_codec.
 * That's because it's too clunky: the hw_write_t prototype does not match
 * i2c_smbus_write_byte_data(), and it's just another layer of overhead.
 */
static int cs4270_i2c_write(struct snd_soc_codec *codec, unsigned int reg,
			    unsigned int value)
{
	u8 *cache = codec->reg_cache;

	if ((reg < CS4270_FIRSTREG) || (reg > CS4270_LASTREG))
		return -EIO;

	/* Only perform an I2C operation if the new value is different */
	if (cache[reg - CS4270_FIRSTREG] != value) {
		struct i2c_client *client = codec->control_data;
		if (i2c_smbus_write_byte_data(client, reg, value)) {
			printk(KERN_ERR "cs4270: I2C write failed\n");
			return -EIO;
		}

		/* We've written to the hardware, so update the cache */
		cache[reg - CS4270_FIRSTREG] = value;
	}

	return 0;
}

/*
 * Program the CS4270 with the given hardware parameters.
 *
 * The .ops functions are used to provide board-specific data, like
 * input frequencies, to this driver.  This function takes that information,
 * combines it with the hardware parameters provided, and programs the
 * hardware accordingly.
 */
static int cs4270_hw_params(struct snd_pcm_substream *substream,
			    struct snd_pcm_hw_params *params,
			    struct snd_soc_dai *dai)
{
	struct snd_soc_pcm_runtime *rtd = substream->private_data;
	struct snd_soc_device *socdev = rtd->socdev;
	struct snd_soc_codec *codec = socdev->codec;
	struct cs4270_private *cs4270 = codec->private_data;
	int ret;
	unsigned int i;
	unsigned int rate;
	unsigned int ratio;
	int reg;

	/* Figure out which MCLK/LRCK ratio to use */

	rate = params_rate(params);	/* Sampling rate, in Hz */
	ratio = cs4270->mclk / rate;	/* MCLK/LRCK ratio */

	for (i = 0; i < NUM_MCLK_RATIOS; i++) {
		if (cs4270_mode_ratios[i].ratio == ratio)
			break;
	}

	if (i == NUM_MCLK_RATIOS) {
		/* We did not find a matching ratio */
		printk(KERN_ERR "cs4270: could not find matching ratio\n");
		return -EINVAL;
	}

	/* Freeze and power-down the codec */

	ret = snd_soc_write(codec, CS4270_PWRCTL, CS4270_PWRCTL_FREEZE |
			    CS4270_PWRCTL_PDN_ADC | CS4270_PWRCTL_PDN_DAC |
			    CS4270_PWRCTL_PDN);
	if (ret < 0) {
		printk(KERN_ERR "cs4270: I2C write failed\n");
		return ret;
	}

	/* Program the mode control register */

	reg = snd_soc_read(codec, CS4270_MODE);
	reg &= ~(CS4270_MODE_SPEED_MASK | CS4270_MODE_DIV_MASK);
	reg |= cs4270_mode_ratios[i].speed_mode | cs4270_mode_ratios[i].mclk;

	ret = snd_soc_write(codec, CS4270_MODE, reg);
	if (ret < 0) {
		printk(KERN_ERR "cs4270: I2C write failed\n");
		return ret;
	}

	/* Program the format register */

	reg = snd_soc_read(codec, CS4270_FORMAT);
	reg &= ~(CS4270_FORMAT_DAC_MASK | CS4270_FORMAT_ADC_MASK);

	switch (cs4270->mode) {
	case SND_SOC_DAIFMT_I2S:
		reg |= CS4270_FORMAT_DAC_I2S | CS4270_FORMAT_ADC_I2S;
		break;
	case SND_SOC_DAIFMT_LEFT_J:
		reg |= CS4270_FORMAT_DAC_LJ | CS4270_FORMAT_ADC_LJ;
		break;
	default:
		printk(KERN_ERR "cs4270: unknown format\n");
		return -EINVAL;
	}

	ret = snd_soc_write(codec, CS4270_FORMAT, reg);
	if (ret < 0) {
		printk(KERN_ERR "cs4270: I2C write failed\n");
		return ret;
	}

	/* Disable auto-mute.  This feature appears to be buggy, because in
	   some situations, auto-mute will not deactivate when it should. */

	reg = snd_soc_read(codec, CS4270_MUTE);
	reg &= ~CS4270_MUTE_AUTO;
	ret = snd_soc_write(codec, CS4270_MUTE, reg);
	if (ret < 0) {
		printk(KERN_ERR "cs4270: I2C write failed\n");
		return ret;
	}

	/* Disable automatic volume control.  It's enabled by default, and
	 * it causes volume change commands to be delayed, sometimes until
	 * after playback has started.
	 */

	reg = cs4270_read_reg_cache(codec, CS4270_TRANS);
	reg &= ~(CS4270_TRANS_SOFT | CS4270_TRANS_ZERO);
	ret = cs4270_i2c_write(codec, CS4270_TRANS, reg);
	if (ret < 0) {
		printk(KERN_ERR "I2C write failed\n");
		return ret;
	}

	/* Thaw and power-up the codec */

	ret = snd_soc_write(codec, CS4270_PWRCTL, 0);
	if (ret < 0) {
		printk(KERN_ERR "cs4270: I2C write failed\n");
		return ret;
	}

	return ret;
}

#ifdef CONFIG_SND_SOC_CS4270_HWMUTE

/*
 * Set the CS4270 external mute
 *
 * This function toggles the mute bits in the MUTE register.  The CS4270's
 * mute capability is intended for external muting circuitry, so if the
 * board does not have the MUTEA or MUTEB pins connected to such circuitry,
 * then this function will do nothing.
 */
static int cs4270_mute(struct snd_soc_dai *dai, int mute)
{
	struct snd_soc_codec *codec = dai->codec;
	int reg6;

	reg6 = snd_soc_read(codec, CS4270_MUTE);

	if (mute)
		reg6 |= CS4270_MUTE_ADC_A | CS4270_MUTE_ADC_B |
			CS4270_MUTE_DAC_A | CS4270_MUTE_DAC_B;
	else
		reg6 &= ~(CS4270_MUTE_ADC_A | CS4270_MUTE_ADC_B |
			  CS4270_MUTE_DAC_A | CS4270_MUTE_DAC_B);

	return snd_soc_write(codec, CS4270_MUTE, reg6);
}

#endif

static int cs4270_i2c_probe(struct i2c_client *, const struct i2c_device_id *);

/* A list of non-DAPM controls that the CS4270 supports */
static const struct snd_kcontrol_new cs4270_snd_controls[] = {
	SOC_DOUBLE_R("Master Playback Volume",
		CS4270_VOLA, CS4270_VOLB, 0, 0xFF, 1)
};

static const struct i2c_device_id cs4270_id[] = {
	{"cs4270", 0},
	{}
};
MODULE_DEVICE_TABLE(i2c, cs4270_id);

static struct i2c_driver cs4270_i2c_driver = {
	.driver = {
		.name = "CS4270 I2C",
		.owner = THIS_MODULE,
	},
	.id_table = cs4270_id,
	.probe = cs4270_i2c_probe,
};

/*
 * Global variable to store socdev for i2c probe function.
 *
 * If struct i2c_driver had a private_data field, we wouldn't need to use
 * cs4270_socdec.  This is the only way to pass the socdev structure to
 * cs4270_i2c_probe().
 *
 * The real solution to cs4270_socdev is to create a mechanism
 * that maps I2C addresses to snd_soc_device structures.  Perhaps the
 * creation of the snd_soc_device object should be moved out of
 * cs4270_probe() and into cs4270_i2c_probe(), but that would make this
 * driver dependent on I2C.  The CS4270 supports "stand-alone" mode, whereby
 * the chip is *not* connected to the I2C bus, but is instead configured via
 * input pins.
 */
static struct snd_soc_device *cs4270_socdev;

/*
 * Initialize the I2C interface of the CS4270
 *
 * This function is called for whenever the I2C subsystem finds a device
 * at a particular address.
 *
 * Note: snd_soc_new_pcms() must be called before this function can be called,
 * because of snd_ctl_add().
 */
static int cs4270_i2c_probe(struct i2c_client *i2c_client,
	const struct i2c_device_id *id)
{
	struct snd_soc_device *socdev = cs4270_socdev;
	struct snd_soc_codec *codec = socdev->codec;
	int i;
	int ret = 0;

	/* Probing all possible addresses has one drawback: if there are
	   multiple CS4270s on the bus, then you cannot specify which
	   socdev is matched with which CS4270.  For now, we just reject
	   this I2C device if the socdev already has one attached. */
	if (codec->control_data)
		return -ENODEV;

	/* Note: codec_dai->codec is NULL here */

	codec->reg_cache = kzalloc(CS4270_NUMREGS, GFP_KERNEL);
	if (!codec->reg_cache) {
		printk(KERN_ERR "cs4270: could not allocate register cache\n");
		ret = -ENOMEM;
		goto error;
	}

	/* Verify that we have a CS4270 */

	ret = i2c_smbus_read_byte_data(i2c_client, CS4270_CHIPID);
	if (ret < 0) {
		printk(KERN_ERR "cs4270: failed to read I2C\n");
		goto error;
	}
	/* The top four bits of the chip ID should be 1100. */
	if ((ret & 0xF0) != 0xC0) {
		/* The device at this address is not a CS4270 codec */
		ret = -ENODEV;
		goto error;
	}

	printk(KERN_INFO "cs4270: found device at I2C address %X\n",
		i2c_client->addr);
	printk(KERN_INFO "cs4270: hardware revision %X\n", ret & 0xF);

	codec->control_data = i2c_client;
	codec->read = cs4270_read_reg_cache;
	codec->write = cs4270_i2c_write;
	codec->reg_cache_size = CS4270_NUMREGS;

	/* The I2C interface is set up, so pre-fill our register cache */

	ret = cs4270_fill_cache(codec);
	if (ret < 0) {
		printk(KERN_ERR "cs4270: failed to fill register cache\n");
		goto error;
	}

	/* Add the non-DAPM controls */

	for (i = 0; i < ARRAY_SIZE(cs4270_snd_controls); i++) {
		struct snd_kcontrol *kctrl =
		snd_soc_cnew(&cs4270_snd_controls[i], codec, NULL);

		ret = snd_ctl_add(codec->card, kctrl);
		if (ret < 0)
			goto error;
	}

	i2c_set_clientdata(i2c_client, codec);

	return 0;

error:
	codec->control_data = NULL;

	kfree(codec->reg_cache);
	codec->reg_cache = NULL;
	codec->reg_cache_size = 0;

	return ret;
}

#endif /* USE_I2C*/

struct snd_soc_dai cs4270_dai = {
	.name = "CS4270",
	.playback = {
		.stream_name = "Playback",
		.channels_min = 1,
		.channels_max = 2,
		.rates = 0,
		.formats = CS4270_FORMATS,
	},
	.capture = {
		.stream_name = "Capture",
		.channels_min = 1,
		.channels_max = 2,
		.rates = 0,
		.formats = CS4270_FORMATS,
	},
};
EXPORT_SYMBOL_GPL(cs4270_dai);

/*
 * ASoC probe function
 *
 * This function is called when the machine driver calls
 * platform_device_add().
 */
static int cs4270_probe(struct platform_device *pdev)
{
	struct snd_soc_device *socdev = platform_get_drvdata(pdev);
	struct snd_soc_codec *codec;
	int ret = 0;

	printk(KERN_INFO "CS4270 ALSA SoC Codec\n");

	/* Allocate enough space for the snd_soc_codec structure
	   and our private data together. */
	codec = kzalloc(ALIGN(sizeof(struct snd_soc_codec), 4) +
			sizeof(struct cs4270_private), GFP_KERNEL);
	if (!codec) {
		printk(KERN_ERR "cs4270: Could not allocate codec structure\n");
		return -ENOMEM;
	}

	mutex_init(&codec->mutex);
	INIT_LIST_HEAD(&codec->dapm_widgets);
	INIT_LIST_HEAD(&codec->dapm_paths);

	codec->name = "CS4270";
	codec->owner = THIS_MODULE;
	codec->dai = &cs4270_dai;
	codec->num_dai = 1;
	codec->private_data = (void *) codec +
		ALIGN(sizeof(struct snd_soc_codec), 4);

	socdev->codec = codec;

	/* Register PCMs */

	ret = snd_soc_new_pcms(socdev, SNDRV_DEFAULT_IDX1, SNDRV_DEFAULT_STR1);
	if (ret < 0) {
		printk(KERN_ERR "cs4270: failed to create PCMs\n");
		goto error_free_codec;
	}

#ifdef USE_I2C
	cs4270_socdev = socdev;

	ret = i2c_add_driver(&cs4270_i2c_driver);
	if (ret) {
		printk(KERN_ERR "cs4270: failed to attach driver");
		goto error_free_pcms;
	}

	/* Did we find a CS4270 on the I2C bus? */
	if (codec->control_data) {
		/* Initialize codec ops */
		cs4270_dai.ops.hw_params = cs4270_hw_params;
		cs4270_dai.ops.set_sysclk = cs4270_set_dai_sysclk;
		cs4270_dai.ops.set_fmt = cs4270_set_dai_fmt;
#ifdef CONFIG_SND_SOC_CS4270_HWMUTE
		cs4270_dai.ops.digital_mute = cs4270_mute;
#endif
	} else
		printk(KERN_INFO "cs4270: no I2C device found, "
			"using stand-alone mode\n");
#else
	printk(KERN_INFO "cs4270: I2C disabled, using stand-alone mode\n");
#endif

	ret = snd_soc_register_card(socdev);
	if (ret < 0) {
		printk(KERN_ERR "cs4270: failed to register card\n");
		goto error_del_driver;
	}

	return 0;

error_del_driver:
#ifdef USE_I2C
	i2c_del_driver(&cs4270_i2c_driver);

error_free_pcms:
#endif
	snd_soc_free_pcms(socdev);

error_free_codec:
	kfree(socdev->codec);
	socdev->codec = NULL;

	return ret;
}

static int cs4270_remove(struct platform_device *pdev)
{
	struct snd_soc_device *socdev = platform_get_drvdata(pdev);

	snd_soc_free_pcms(socdev);

#ifdef USE_I2C
	i2c_del_driver(&cs4270_i2c_driver);
#endif

	kfree(socdev->codec);
	socdev->codec = NULL;

	return 0;
}

/*
 * ASoC codec device structure
 *
 * Assign this variable to the codec_dev field of the machine driver's
 * snd_soc_device structure.
 */
struct snd_soc_codec_device soc_codec_device_cs4270 = {
	.probe = 	cs4270_probe,
	.remove = 	cs4270_remove
};
EXPORT_SYMBOL_GPL(soc_codec_device_cs4270);

MODULE_AUTHOR("Timur Tabi <timur@freescale.com>");
MODULE_DESCRIPTION("Cirrus Logic CS4270 ALSA SoC Codec Driver");
MODULE_LICENSE("GPL");
OpenPOWER on IntegriCloud