xref: /openbmc/linux/sound/soc/atmel/atmel-i2s.c (revision 63705da3)
1 // SPDX-License-Identifier: GPL-2.0-only
2 /*
3  * Driver for Atmel I2S controller
4  *
5  * Copyright (C) 2015 Atmel Corporation
6  *
7  * Author: Cyrille Pitchen <cyrille.pitchen@atmel.com>
8  */
9 
10 #include <linux/init.h>
11 #include <linux/module.h>
12 #include <linux/device.h>
13 #include <linux/slab.h>
14 #include <linux/delay.h>
15 #include <linux/io.h>
16 #include <linux/clk.h>
17 #include <linux/mfd/syscon.h>
18 
19 #include <sound/core.h>
20 #include <sound/pcm.h>
21 #include <sound/pcm_params.h>
22 #include <sound/initval.h>
23 #include <sound/soc.h>
24 #include <sound/dmaengine_pcm.h>
25 
26 #define ATMEL_I2SC_MAX_TDM_CHANNELS	8
27 
28 /*
29  * ---- I2S Controller Register map ----
30  */
31 #define ATMEL_I2SC_CR		0x0000	/* Control Register */
32 #define ATMEL_I2SC_MR		0x0004	/* Mode Register */
33 #define ATMEL_I2SC_SR		0x0008	/* Status Register */
34 #define ATMEL_I2SC_SCR		0x000c	/* Status Clear Register */
35 #define ATMEL_I2SC_SSR		0x0010	/* Status Set Register */
36 #define ATMEL_I2SC_IER		0x0014	/* Interrupt Enable Register */
37 #define ATMEL_I2SC_IDR		0x0018	/* Interrupt Disable Register */
38 #define ATMEL_I2SC_IMR		0x001c	/* Interrupt Mask Register */
39 #define ATMEL_I2SC_RHR		0x0020	/* Receiver Holding Register */
40 #define ATMEL_I2SC_THR		0x0024	/* Transmitter Holding Register */
41 #define ATMEL_I2SC_VERSION	0x0028	/* Version Register */
42 
43 /*
44  * ---- Control Register (Write-only) ----
45  */
46 #define ATMEL_I2SC_CR_RXEN	BIT(0)	/* Receiver Enable */
47 #define ATMEL_I2SC_CR_RXDIS	BIT(1)	/* Receiver Disable */
48 #define ATMEL_I2SC_CR_CKEN	BIT(2)	/* Clock Enable */
49 #define ATMEL_I2SC_CR_CKDIS	BIT(3)	/* Clock Disable */
50 #define ATMEL_I2SC_CR_TXEN	BIT(4)	/* Transmitter Enable */
51 #define ATMEL_I2SC_CR_TXDIS	BIT(5)	/* Transmitter Disable */
52 #define ATMEL_I2SC_CR_SWRST	BIT(7)	/* Software Reset */
53 
54 /*
55  * ---- Mode Register (Read/Write) ----
56  */
57 #define ATMEL_I2SC_MR_MODE_MASK		GENMASK(0, 0)
58 #define ATMEL_I2SC_MR_MODE_SLAVE	(0 << 0)
59 #define ATMEL_I2SC_MR_MODE_MASTER	(1 << 0)
60 
61 #define ATMEL_I2SC_MR_DATALENGTH_MASK		GENMASK(4, 2)
62 #define ATMEL_I2SC_MR_DATALENGTH_32_BITS	(0 << 2)
63 #define ATMEL_I2SC_MR_DATALENGTH_24_BITS	(1 << 2)
64 #define ATMEL_I2SC_MR_DATALENGTH_20_BITS	(2 << 2)
65 #define ATMEL_I2SC_MR_DATALENGTH_18_BITS	(3 << 2)
66 #define ATMEL_I2SC_MR_DATALENGTH_16_BITS	(4 << 2)
67 #define ATMEL_I2SC_MR_DATALENGTH_16_BITS_COMPACT	(5 << 2)
68 #define ATMEL_I2SC_MR_DATALENGTH_8_BITS		(6 << 2)
69 #define ATMEL_I2SC_MR_DATALENGTH_8_BITS_COMPACT	(7 << 2)
70 
71 #define ATMEL_I2SC_MR_FORMAT_MASK	GENMASK(7, 6)
72 #define ATMEL_I2SC_MR_FORMAT_I2S	(0 << 6)
73 #define ATMEL_I2SC_MR_FORMAT_LJ		(1 << 6)  /* Left Justified */
74 #define ATMEL_I2SC_MR_FORMAT_TDM	(2 << 6)
75 #define ATMEL_I2SC_MR_FORMAT_TDMLJ	(3 << 6)
76 
77 /* Left audio samples duplicated to right audio channel */
78 #define ATMEL_I2SC_MR_RXMONO		BIT(8)
79 
80 /* Receiver uses one DMA channel ... */
81 #define ATMEL_I2SC_MR_RXDMA_MASK	GENMASK(9, 9)
82 #define ATMEL_I2SC_MR_RXDMA_SINGLE	(0 << 9)  /* for all audio channels */
83 #define ATMEL_I2SC_MR_RXDMA_MULTIPLE	(1 << 9)  /* per audio channel */
84 
85 /* I2SDO output of I2SC is internally connected to I2SDI input */
86 #define ATMEL_I2SC_MR_RXLOOP		BIT(10)
87 
88 /* Left audio samples duplicated to right audio channel */
89 #define ATMEL_I2SC_MR_TXMONO		BIT(12)
90 
91 /* Transmitter uses one DMA channel ... */
92 #define ATMEL_I2SC_MR_TXDMA_MASK	GENMASK(13, 13)
93 #define ATMEL_I2SC_MR_TXDMA_SINGLE	(0 << 13)  /* for all audio channels */
94 #define ATMEL_I2SC_MR_TXDME_MULTIPLE	(1 << 13)  /* per audio channel */
95 
96 /* x sample transmitted when underrun */
97 #define ATMEL_I2SC_MR_TXSAME_MASK	GENMASK(14, 14)
98 #define ATMEL_I2SC_MR_TXSAME_ZERO	(0 << 14)  /* Zero sample */
99 #define ATMEL_I2SC_MR_TXSAME_PREVIOUS	(1 << 14)  /* Previous sample */
100 
101 /* Audio Clock to I2SC Master Clock ratio */
102 #define ATMEL_I2SC_MR_IMCKDIV_MASK	GENMASK(21, 16)
103 #define ATMEL_I2SC_MR_IMCKDIV(div) \
104 	(((div) << 16) & ATMEL_I2SC_MR_IMCKDIV_MASK)
105 
106 /* Master Clock to fs ratio */
107 #define ATMEL_I2SC_MR_IMCKFS_MASK	GENMASK(29, 24)
108 #define ATMEL_I2SC_MR_IMCKFS(fs) \
109 	(((fs) << 24) & ATMEL_I2SC_MR_IMCKFS_MASK)
110 
111 /* Master Clock mode */
112 #define ATMEL_I2SC_MR_IMCKMODE_MASK	GENMASK(30, 30)
113 /* 0: No master clock generated (selected clock drives I2SCK pin) */
114 #define ATMEL_I2SC_MR_IMCKMODE_I2SCK	(0 << 30)
115 /* 1: master clock generated (internally generated clock drives I2SMCK pin) */
116 #define ATMEL_I2SC_MR_IMCKMODE_I2SMCK	(1 << 30)
117 
118 /* Slot Width */
119 /* 0: slot is 32 bits wide for DATALENGTH = 18/20/24 bits. */
120 /* 1: slot is 24 bits wide for DATALENGTH = 18/20/24 bits. */
121 #define ATMEL_I2SC_MR_IWS		BIT(31)
122 
123 /*
124  * ---- Status Registers ----
125  */
126 #define ATMEL_I2SC_SR_RXEN	BIT(0)	/* Receiver Enabled */
127 #define ATMEL_I2SC_SR_RXRDY	BIT(1)	/* Receive Ready */
128 #define ATMEL_I2SC_SR_RXOR	BIT(2)	/* Receive Overrun */
129 
130 #define ATMEL_I2SC_SR_TXEN	BIT(4)	/* Transmitter Enabled */
131 #define ATMEL_I2SC_SR_TXRDY	BIT(5)	/* Transmit Ready */
132 #define ATMEL_I2SC_SR_TXUR	BIT(6)	/* Transmit Underrun */
133 
134 /* Receive Overrun Channel */
135 #define ATMEL_I2SC_SR_RXORCH_MASK	GENMASK(15, 8)
136 #define ATMEL_I2SC_SR_RXORCH(ch)	(1 << (((ch) & 0x7) + 8))
137 
138 /* Transmit Underrun Channel */
139 #define ATMEL_I2SC_SR_TXURCH_MASK	GENMASK(27, 20)
140 #define ATMEL_I2SC_SR_TXURCH(ch)	(1 << (((ch) & 0x7) + 20))
141 
142 /*
143  * ---- Interrupt Enable/Disable/Mask Registers ----
144  */
145 #define ATMEL_I2SC_INT_RXRDY	ATMEL_I2SC_SR_RXRDY
146 #define ATMEL_I2SC_INT_RXOR	ATMEL_I2SC_SR_RXOR
147 #define ATMEL_I2SC_INT_TXRDY	ATMEL_I2SC_SR_TXRDY
148 #define ATMEL_I2SC_INT_TXUR	ATMEL_I2SC_SR_TXUR
149 
150 static const struct regmap_config atmel_i2s_regmap_config = {
151 	.reg_bits = 32,
152 	.reg_stride = 4,
153 	.val_bits = 32,
154 	.max_register = ATMEL_I2SC_VERSION,
155 };
156 
157 struct atmel_i2s_gck_param {
158 	int		fs;
159 	unsigned long	mck;
160 	int		imckdiv;
161 	int		imckfs;
162 };
163 
164 #define I2S_MCK_12M288		12288000UL
165 #define I2S_MCK_11M2896		11289600UL
166 
167 /* mck = (32 * (imckfs+1) / (imckdiv+1)) * fs */
168 static const struct atmel_i2s_gck_param gck_params[] = {
169 	/* mck = 12.288MHz */
170 	{  8000, I2S_MCK_12M288, 0, 47},	/* mck = 1536 fs */
171 	{ 16000, I2S_MCK_12M288, 1, 47},	/* mck =  768 fs */
172 	{ 24000, I2S_MCK_12M288, 3, 63},	/* mck =  512 fs */
173 	{ 32000, I2S_MCK_12M288, 3, 47},	/* mck =  384 fs */
174 	{ 48000, I2S_MCK_12M288, 7, 63},	/* mck =  256 fs */
175 	{ 64000, I2S_MCK_12M288, 7, 47},	/* mck =  192 fs */
176 	{ 96000, I2S_MCK_12M288, 7, 31},	/* mck =  128 fs */
177 	{192000, I2S_MCK_12M288, 7, 15},	/* mck =   64 fs */
178 
179 	/* mck = 11.2896MHz */
180 	{ 11025, I2S_MCK_11M2896, 1, 63},	/* mck = 1024 fs */
181 	{ 22050, I2S_MCK_11M2896, 3, 63},	/* mck =  512 fs */
182 	{ 44100, I2S_MCK_11M2896, 7, 63},	/* mck =  256 fs */
183 	{ 88200, I2S_MCK_11M2896, 7, 31},	/* mck =  128 fs */
184 	{176400, I2S_MCK_11M2896, 7, 15},	/* mck =   64 fs */
185 };
186 
187 struct atmel_i2s_dev;
188 
189 struct atmel_i2s_caps {
190 	int	(*mck_init)(struct atmel_i2s_dev *, struct device_node *np);
191 };
192 
193 struct atmel_i2s_dev {
194 	struct device				*dev;
195 	struct regmap				*regmap;
196 	struct clk				*pclk;
197 	struct clk				*gclk;
198 	struct snd_dmaengine_dai_dma_data	playback;
199 	struct snd_dmaengine_dai_dma_data	capture;
200 	unsigned int				fmt;
201 	const struct atmel_i2s_gck_param	*gck_param;
202 	const struct atmel_i2s_caps		*caps;
203 	int					clk_use_no;
204 };
205 
206 static irqreturn_t atmel_i2s_interrupt(int irq, void *dev_id)
207 {
208 	struct atmel_i2s_dev *dev = dev_id;
209 	unsigned int sr, imr, pending, ch, mask;
210 	irqreturn_t ret = IRQ_NONE;
211 
212 	regmap_read(dev->regmap, ATMEL_I2SC_SR, &sr);
213 	regmap_read(dev->regmap, ATMEL_I2SC_IMR, &imr);
214 	pending = sr & imr;
215 
216 	if (!pending)
217 		return IRQ_NONE;
218 
219 	if (pending & ATMEL_I2SC_INT_RXOR) {
220 		mask = ATMEL_I2SC_SR_RXOR;
221 
222 		for (ch = 0; ch < ATMEL_I2SC_MAX_TDM_CHANNELS; ++ch) {
223 			if (sr & ATMEL_I2SC_SR_RXORCH(ch)) {
224 				mask |= ATMEL_I2SC_SR_RXORCH(ch);
225 				dev_err(dev->dev,
226 					"RX overrun on channel %d\n", ch);
227 			}
228 		}
229 		regmap_write(dev->regmap, ATMEL_I2SC_SCR, mask);
230 		ret = IRQ_HANDLED;
231 	}
232 
233 	if (pending & ATMEL_I2SC_INT_TXUR) {
234 		mask = ATMEL_I2SC_SR_TXUR;
235 
236 		for (ch = 0; ch < ATMEL_I2SC_MAX_TDM_CHANNELS; ++ch) {
237 			if (sr & ATMEL_I2SC_SR_TXURCH(ch)) {
238 				mask |= ATMEL_I2SC_SR_TXURCH(ch);
239 				dev_err(dev->dev,
240 					"TX underrun on channel %d\n", ch);
241 			}
242 		}
243 		regmap_write(dev->regmap, ATMEL_I2SC_SCR, mask);
244 		ret = IRQ_HANDLED;
245 	}
246 
247 	return ret;
248 }
249 
250 #define ATMEL_I2S_RATES		SNDRV_PCM_RATE_8000_192000
251 
252 #define ATMEL_I2S_FORMATS	(SNDRV_PCM_FMTBIT_S8 |		\
253 				 SNDRV_PCM_FMTBIT_S16_LE |	\
254 				 SNDRV_PCM_FMTBIT_S18_3LE |	\
255 				 SNDRV_PCM_FMTBIT_S20_3LE |	\
256 				 SNDRV_PCM_FMTBIT_S24_3LE |	\
257 				 SNDRV_PCM_FMTBIT_S24_LE |	\
258 				 SNDRV_PCM_FMTBIT_S32_LE)
259 
260 static int atmel_i2s_set_dai_fmt(struct snd_soc_dai *dai, unsigned int fmt)
261 {
262 	struct atmel_i2s_dev *dev = snd_soc_dai_get_drvdata(dai);
263 
264 	dev->fmt = fmt;
265 	return 0;
266 }
267 
268 static int atmel_i2s_prepare(struct snd_pcm_substream *substream,
269 			     struct snd_soc_dai *dai)
270 {
271 	struct atmel_i2s_dev *dev = snd_soc_dai_get_drvdata(dai);
272 	bool is_playback = (substream->stream == SNDRV_PCM_STREAM_PLAYBACK);
273 	unsigned int rhr, sr = 0;
274 
275 	if (is_playback) {
276 		regmap_read(dev->regmap, ATMEL_I2SC_SR, &sr);
277 		if (sr & ATMEL_I2SC_SR_RXRDY) {
278 			/*
279 			 * The RX Ready flag should not be set. However if here,
280 			 * we flush (read) the Receive Holding Register to start
281 			 * from a clean state.
282 			 */
283 			dev_dbg(dev->dev, "RXRDY is set\n");
284 			regmap_read(dev->regmap, ATMEL_I2SC_RHR, &rhr);
285 		}
286 	}
287 
288 	return 0;
289 }
290 
291 static int atmel_i2s_get_gck_param(struct atmel_i2s_dev *dev, int fs)
292 {
293 	int i, best;
294 
295 	if (!dev->gclk) {
296 		dev_err(dev->dev, "cannot generate the I2S Master Clock\n");
297 		return -EINVAL;
298 	}
299 
300 	/*
301 	 * Find the best possible settings to generate the I2S Master Clock
302 	 * from the PLL Audio.
303 	 */
304 	dev->gck_param = NULL;
305 	best = INT_MAX;
306 	for (i = 0; i < ARRAY_SIZE(gck_params); ++i) {
307 		const struct atmel_i2s_gck_param *gck_param = &gck_params[i];
308 		int val = abs(fs - gck_param->fs);
309 
310 		if (val < best) {
311 			best = val;
312 			dev->gck_param = gck_param;
313 		}
314 	}
315 
316 	return 0;
317 }
318 
319 static int atmel_i2s_hw_params(struct snd_pcm_substream *substream,
320 			       struct snd_pcm_hw_params *params,
321 			       struct snd_soc_dai *dai)
322 {
323 	struct atmel_i2s_dev *dev = snd_soc_dai_get_drvdata(dai);
324 	bool is_playback = (substream->stream == SNDRV_PCM_STREAM_PLAYBACK);
325 	unsigned int mr = 0, mr_mask;
326 	int ret;
327 
328 	mr_mask = ATMEL_I2SC_MR_FORMAT_MASK | ATMEL_I2SC_MR_MODE_MASK |
329 		ATMEL_I2SC_MR_DATALENGTH_MASK;
330 	if (is_playback)
331 		mr_mask |= ATMEL_I2SC_MR_TXMONO;
332 	else
333 		mr_mask |= ATMEL_I2SC_MR_RXMONO;
334 
335 	switch (dev->fmt & SND_SOC_DAIFMT_FORMAT_MASK) {
336 	case SND_SOC_DAIFMT_I2S:
337 		mr |= ATMEL_I2SC_MR_FORMAT_I2S;
338 		break;
339 
340 	default:
341 		dev_err(dev->dev, "unsupported bus format\n");
342 		return -EINVAL;
343 	}
344 
345 	switch (dev->fmt & SND_SOC_DAIFMT_CLOCK_PROVIDER_MASK) {
346 	case SND_SOC_DAIFMT_CBC_CFC:
347 		/* codec is slave, so cpu is master */
348 		mr |= ATMEL_I2SC_MR_MODE_MASTER;
349 		ret = atmel_i2s_get_gck_param(dev, params_rate(params));
350 		if (ret)
351 			return ret;
352 		break;
353 
354 	case SND_SOC_DAIFMT_CBP_CFP:
355 		/* codec is master, so cpu is slave */
356 		mr |= ATMEL_I2SC_MR_MODE_SLAVE;
357 		dev->gck_param = NULL;
358 		break;
359 
360 	default:
361 		dev_err(dev->dev, "unsupported master/slave mode\n");
362 		return -EINVAL;
363 	}
364 
365 	switch (params_channels(params)) {
366 	case 1:
367 		if (is_playback)
368 			mr |= ATMEL_I2SC_MR_TXMONO;
369 		else
370 			mr |= ATMEL_I2SC_MR_RXMONO;
371 		break;
372 	case 2:
373 		break;
374 	default:
375 		dev_err(dev->dev, "unsupported number of audio channels\n");
376 		return -EINVAL;
377 	}
378 
379 	switch (params_format(params)) {
380 	case SNDRV_PCM_FORMAT_S8:
381 		mr |= ATMEL_I2SC_MR_DATALENGTH_8_BITS;
382 		break;
383 
384 	case SNDRV_PCM_FORMAT_S16_LE:
385 		mr |= ATMEL_I2SC_MR_DATALENGTH_16_BITS;
386 		break;
387 
388 	case SNDRV_PCM_FORMAT_S18_3LE:
389 		mr |= ATMEL_I2SC_MR_DATALENGTH_18_BITS | ATMEL_I2SC_MR_IWS;
390 		break;
391 
392 	case SNDRV_PCM_FORMAT_S20_3LE:
393 		mr |= ATMEL_I2SC_MR_DATALENGTH_20_BITS | ATMEL_I2SC_MR_IWS;
394 		break;
395 
396 	case SNDRV_PCM_FORMAT_S24_3LE:
397 		mr |= ATMEL_I2SC_MR_DATALENGTH_24_BITS | ATMEL_I2SC_MR_IWS;
398 		break;
399 
400 	case SNDRV_PCM_FORMAT_S24_LE:
401 		mr |= ATMEL_I2SC_MR_DATALENGTH_24_BITS;
402 		break;
403 
404 	case SNDRV_PCM_FORMAT_S32_LE:
405 		mr |= ATMEL_I2SC_MR_DATALENGTH_32_BITS;
406 		break;
407 
408 	default:
409 		dev_err(dev->dev, "unsupported size/endianness for audio samples\n");
410 		return -EINVAL;
411 	}
412 
413 	return regmap_update_bits(dev->regmap, ATMEL_I2SC_MR, mr_mask, mr);
414 }
415 
416 static int atmel_i2s_switch_mck_generator(struct atmel_i2s_dev *dev,
417 					  bool enabled)
418 {
419 	unsigned int mr, mr_mask;
420 	unsigned long gclk_rate;
421 	int ret;
422 
423 	mr = 0;
424 	mr_mask = (ATMEL_I2SC_MR_IMCKDIV_MASK |
425 		   ATMEL_I2SC_MR_IMCKFS_MASK |
426 		   ATMEL_I2SC_MR_IMCKMODE_MASK);
427 
428 	if (!enabled) {
429 		/* Disable the I2S Master Clock generator. */
430 		ret = regmap_write(dev->regmap, ATMEL_I2SC_CR,
431 				   ATMEL_I2SC_CR_CKDIS);
432 		if (ret)
433 			return ret;
434 
435 		/* Reset the I2S Master Clock generator settings. */
436 		ret = regmap_update_bits(dev->regmap, ATMEL_I2SC_MR,
437 					 mr_mask, mr);
438 		if (ret)
439 			return ret;
440 
441 		/* Disable/unprepare the PMC generated clock. */
442 		clk_disable_unprepare(dev->gclk);
443 
444 		return 0;
445 	}
446 
447 	if (!dev->gck_param)
448 		return -EINVAL;
449 
450 	gclk_rate = dev->gck_param->mck * (dev->gck_param->imckdiv + 1);
451 
452 	ret = clk_set_rate(dev->gclk, gclk_rate);
453 	if (ret)
454 		return ret;
455 
456 	ret = clk_prepare_enable(dev->gclk);
457 	if (ret)
458 		return ret;
459 
460 	/* Update the Mode Register to generate the I2S Master Clock. */
461 	mr |= ATMEL_I2SC_MR_IMCKDIV(dev->gck_param->imckdiv);
462 	mr |= ATMEL_I2SC_MR_IMCKFS(dev->gck_param->imckfs);
463 	mr |= ATMEL_I2SC_MR_IMCKMODE_I2SMCK;
464 	ret = regmap_update_bits(dev->regmap, ATMEL_I2SC_MR, mr_mask, mr);
465 	if (ret)
466 		return ret;
467 
468 	/* Finally enable the I2S Master Clock generator. */
469 	return regmap_write(dev->regmap, ATMEL_I2SC_CR,
470 			    ATMEL_I2SC_CR_CKEN);
471 }
472 
473 static int atmel_i2s_trigger(struct snd_pcm_substream *substream, int cmd,
474 			     struct snd_soc_dai *dai)
475 {
476 	struct atmel_i2s_dev *dev = snd_soc_dai_get_drvdata(dai);
477 	bool is_playback = (substream->stream == SNDRV_PCM_STREAM_PLAYBACK);
478 	bool is_master, mck_enabled;
479 	unsigned int cr, mr;
480 	int err;
481 
482 	switch (cmd) {
483 	case SNDRV_PCM_TRIGGER_START:
484 	case SNDRV_PCM_TRIGGER_RESUME:
485 	case SNDRV_PCM_TRIGGER_PAUSE_RELEASE:
486 		cr = is_playback ? ATMEL_I2SC_CR_TXEN : ATMEL_I2SC_CR_RXEN;
487 		mck_enabled = true;
488 		break;
489 	case SNDRV_PCM_TRIGGER_STOP:
490 	case SNDRV_PCM_TRIGGER_SUSPEND:
491 	case SNDRV_PCM_TRIGGER_PAUSE_PUSH:
492 		cr = is_playback ? ATMEL_I2SC_CR_TXDIS : ATMEL_I2SC_CR_RXDIS;
493 		mck_enabled = false;
494 		break;
495 	default:
496 		return -EINVAL;
497 	}
498 
499 	/* Read the Mode Register to retrieve the master/slave state. */
500 	err = regmap_read(dev->regmap, ATMEL_I2SC_MR, &mr);
501 	if (err)
502 		return err;
503 	is_master = (mr & ATMEL_I2SC_MR_MODE_MASK) == ATMEL_I2SC_MR_MODE_MASTER;
504 
505 	/* If master starts, enable the audio clock. */
506 	if (is_master && mck_enabled) {
507 		if (!dev->clk_use_no) {
508 			err = atmel_i2s_switch_mck_generator(dev, true);
509 			if (err)
510 				return err;
511 		}
512 		dev->clk_use_no++;
513 	}
514 
515 	err = regmap_write(dev->regmap, ATMEL_I2SC_CR, cr);
516 	if (err)
517 		return err;
518 
519 	/* If master stops, disable the audio clock. */
520 	if (is_master && !mck_enabled) {
521 		if (dev->clk_use_no == 1) {
522 			err = atmel_i2s_switch_mck_generator(dev, false);
523 			if (err)
524 				return err;
525 		}
526 		dev->clk_use_no--;
527 	}
528 
529 	return err;
530 }
531 
532 static const struct snd_soc_dai_ops atmel_i2s_dai_ops = {
533 	.prepare	= atmel_i2s_prepare,
534 	.trigger	= atmel_i2s_trigger,
535 	.hw_params	= atmel_i2s_hw_params,
536 	.set_fmt	= atmel_i2s_set_dai_fmt,
537 };
538 
539 static int atmel_i2s_dai_probe(struct snd_soc_dai *dai)
540 {
541 	struct atmel_i2s_dev *dev = snd_soc_dai_get_drvdata(dai);
542 
543 	snd_soc_dai_init_dma_data(dai, &dev->playback, &dev->capture);
544 	return 0;
545 }
546 
547 static struct snd_soc_dai_driver atmel_i2s_dai = {
548 	.probe	= atmel_i2s_dai_probe,
549 	.playback = {
550 		.channels_min = 1,
551 		.channels_max = 2,
552 		.rates = ATMEL_I2S_RATES,
553 		.formats = ATMEL_I2S_FORMATS,
554 	},
555 	.capture = {
556 		.channels_min = 1,
557 		.channels_max = 2,
558 		.rates = ATMEL_I2S_RATES,
559 		.formats = ATMEL_I2S_FORMATS,
560 	},
561 	.ops = &atmel_i2s_dai_ops,
562 	.symmetric_rate = 1,
563 	.symmetric_sample_bits = 1,
564 };
565 
566 static const struct snd_soc_component_driver atmel_i2s_component = {
567 	.name	= "atmel-i2s",
568 };
569 
570 static int atmel_i2s_sama5d2_mck_init(struct atmel_i2s_dev *dev,
571 				      struct device_node *np)
572 {
573 	struct clk *muxclk;
574 	int err;
575 
576 	if (!dev->gclk)
577 		return 0;
578 
579 	/* muxclk is optional, so we return error for probe defer only */
580 	muxclk = devm_clk_get(dev->dev, "muxclk");
581 	if (IS_ERR(muxclk)) {
582 		err = PTR_ERR(muxclk);
583 		if (err == -EPROBE_DEFER)
584 			return -EPROBE_DEFER;
585 		dev_dbg(dev->dev,
586 			"failed to get the I2S clock control: %d\n", err);
587 		return 0;
588 	}
589 
590 	return clk_set_parent(muxclk, dev->gclk);
591 }
592 
593 static const struct atmel_i2s_caps atmel_i2s_sama5d2_caps = {
594 	.mck_init = atmel_i2s_sama5d2_mck_init,
595 };
596 
597 static const struct of_device_id atmel_i2s_dt_ids[] = {
598 	{
599 		.compatible = "atmel,sama5d2-i2s",
600 		.data = (void *)&atmel_i2s_sama5d2_caps,
601 	},
602 
603 	{ /* sentinel */ }
604 };
605 
606 MODULE_DEVICE_TABLE(of, atmel_i2s_dt_ids);
607 
608 static int atmel_i2s_probe(struct platform_device *pdev)
609 {
610 	struct device_node *np = pdev->dev.of_node;
611 	const struct of_device_id *match;
612 	struct atmel_i2s_dev *dev;
613 	struct resource *mem;
614 	struct regmap *regmap;
615 	void __iomem *base;
616 	int irq;
617 	int err;
618 	unsigned int pcm_flags = 0;
619 	unsigned int version;
620 
621 	/* Get memory for driver data. */
622 	dev = devm_kzalloc(&pdev->dev, sizeof(*dev), GFP_KERNEL);
623 	if (!dev)
624 		return -ENOMEM;
625 
626 	/* Get hardware capabilities. */
627 	match = of_match_node(atmel_i2s_dt_ids, np);
628 	if (match)
629 		dev->caps = match->data;
630 
631 	/* Map I/O registers. */
632 	base = devm_platform_get_and_ioremap_resource(pdev, 0, &mem);
633 	if (IS_ERR(base))
634 		return PTR_ERR(base);
635 
636 	regmap = devm_regmap_init_mmio(&pdev->dev, base,
637 				       &atmel_i2s_regmap_config);
638 	if (IS_ERR(regmap))
639 		return PTR_ERR(regmap);
640 
641 	/* Request IRQ. */
642 	irq = platform_get_irq(pdev, 0);
643 	if (irq < 0)
644 		return irq;
645 
646 	err = devm_request_irq(&pdev->dev, irq, atmel_i2s_interrupt, 0,
647 			       dev_name(&pdev->dev), dev);
648 	if (err)
649 		return err;
650 
651 	/* Get the peripheral clock. */
652 	dev->pclk = devm_clk_get(&pdev->dev, "pclk");
653 	if (IS_ERR(dev->pclk)) {
654 		err = PTR_ERR(dev->pclk);
655 		dev_err(&pdev->dev,
656 			"failed to get the peripheral clock: %d\n", err);
657 		return err;
658 	}
659 
660 	/* Get audio clock to generate the I2S Master Clock (I2S_MCK) */
661 	dev->gclk = devm_clk_get(&pdev->dev, "gclk");
662 	if (IS_ERR(dev->gclk)) {
663 		if (PTR_ERR(dev->gclk) == -EPROBE_DEFER)
664 			return -EPROBE_DEFER;
665 		/* Master Mode not supported */
666 		dev->gclk = NULL;
667 	}
668 	dev->dev = &pdev->dev;
669 	dev->regmap = regmap;
670 	platform_set_drvdata(pdev, dev);
671 
672 	/* Do hardware specific settings to initialize I2S_MCK generator */
673 	if (dev->caps && dev->caps->mck_init) {
674 		err = dev->caps->mck_init(dev, np);
675 		if (err)
676 			return err;
677 	}
678 
679 	/* Enable the peripheral clock. */
680 	err = clk_prepare_enable(dev->pclk);
681 	if (err)
682 		return err;
683 
684 	/* Get IP version. */
685 	regmap_read(dev->regmap, ATMEL_I2SC_VERSION, &version);
686 	dev_info(&pdev->dev, "hw version: %#x\n", version);
687 
688 	/* Enable error interrupts. */
689 	regmap_write(dev->regmap, ATMEL_I2SC_IER,
690 		     ATMEL_I2SC_INT_RXOR | ATMEL_I2SC_INT_TXUR);
691 
692 	err = devm_snd_soc_register_component(&pdev->dev,
693 					      &atmel_i2s_component,
694 					      &atmel_i2s_dai, 1);
695 	if (err) {
696 		dev_err(&pdev->dev, "failed to register DAI: %d\n", err);
697 		clk_disable_unprepare(dev->pclk);
698 		return err;
699 	}
700 
701 	/* Prepare DMA config. */
702 	dev->playback.addr	= (dma_addr_t)mem->start + ATMEL_I2SC_THR;
703 	dev->playback.maxburst	= 1;
704 	dev->capture.addr	= (dma_addr_t)mem->start + ATMEL_I2SC_RHR;
705 	dev->capture.maxburst	= 1;
706 
707 	if (of_property_match_string(np, "dma-names", "rx-tx") == 0)
708 		pcm_flags |= SND_DMAENGINE_PCM_FLAG_HALF_DUPLEX;
709 	err = devm_snd_dmaengine_pcm_register(&pdev->dev, NULL, pcm_flags);
710 	if (err) {
711 		dev_err(&pdev->dev, "failed to register PCM: %d\n", err);
712 		clk_disable_unprepare(dev->pclk);
713 		return err;
714 	}
715 
716 	return 0;
717 }
718 
719 static int atmel_i2s_remove(struct platform_device *pdev)
720 {
721 	struct atmel_i2s_dev *dev = platform_get_drvdata(pdev);
722 
723 	clk_disable_unprepare(dev->pclk);
724 
725 	return 0;
726 }
727 
728 static struct platform_driver atmel_i2s_driver = {
729 	.driver		= {
730 		.name	= "atmel_i2s",
731 		.of_match_table	= of_match_ptr(atmel_i2s_dt_ids),
732 	},
733 	.probe		= atmel_i2s_probe,
734 	.remove		= atmel_i2s_remove,
735 };
736 module_platform_driver(atmel_i2s_driver);
737 
738 MODULE_DESCRIPTION("Atmel I2S Controller driver");
739 MODULE_AUTHOR("Cyrille Pitchen <cyrille.pitchen@atmel.com>");
740 MODULE_LICENSE("GPL v2");
741