xref: /openbmc/linux/sound/soc/atmel/atmel-i2s.c (revision 73ad0df5)
1 /*
2  * Driver for Atmel I2S controller
3  *
4  * Copyright (C) 2015 Atmel Corporation
5  *
6  * Author: Cyrille Pitchen <cyrille.pitchen@atmel.com>
7  *
8  * This program is free software; you can redistribute it and/or modify it
9  * under the terms of the GNU General Public License version 2 as published by
10  * the Free Software Foundation.
11  *
12  * This program is distributed in the hope that it will be useful, but WITHOUT
13  * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
14  * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License for
15  * more details.
16  *
17  * You should have received a copy of the GNU General Public License along with
18  * this program.  If not, see <http://www.gnu.org/licenses/>.
19  */
20 
21 #include <linux/init.h>
22 #include <linux/module.h>
23 #include <linux/device.h>
24 #include <linux/slab.h>
25 #include <linux/delay.h>
26 #include <linux/io.h>
27 #include <linux/clk.h>
28 #include <linux/mfd/syscon.h>
29 
30 #include <sound/core.h>
31 #include <sound/pcm.h>
32 #include <sound/pcm_params.h>
33 #include <sound/initval.h>
34 #include <sound/soc.h>
35 #include <sound/dmaengine_pcm.h>
36 
37 #define ATMEL_I2SC_MAX_TDM_CHANNELS	8
38 
39 /*
40  * ---- I2S Controller Register map ----
41  */
42 #define ATMEL_I2SC_CR		0x0000	/* Control Register */
43 #define ATMEL_I2SC_MR		0x0004	/* Mode Register */
44 #define ATMEL_I2SC_SR		0x0008	/* Status Register */
45 #define ATMEL_I2SC_SCR		0x000c	/* Status Clear Register */
46 #define ATMEL_I2SC_SSR		0x0010	/* Status Set Register */
47 #define ATMEL_I2SC_IER		0x0014	/* Interrupt Enable Register */
48 #define ATMEL_I2SC_IDR		0x0018	/* Interrupt Disable Register */
49 #define ATMEL_I2SC_IMR		0x001c	/* Interrupt Mask Register */
50 #define ATMEL_I2SC_RHR		0x0020	/* Receiver Holding Register */
51 #define ATMEL_I2SC_THR		0x0024	/* Transmitter Holding Register */
52 #define ATMEL_I2SC_VERSION	0x0028	/* Version Register */
53 
54 /*
55  * ---- Control Register (Write-only) ----
56  */
57 #define ATMEL_I2SC_CR_RXEN	BIT(0)	/* Receiver Enable */
58 #define ATMEL_I2SC_CR_RXDIS	BIT(1)	/* Receiver Disable */
59 #define ATMEL_I2SC_CR_CKEN	BIT(2)	/* Clock Enable */
60 #define ATMEL_I2SC_CR_CKDIS	BIT(3)	/* Clock Disable */
61 #define ATMEL_I2SC_CR_TXEN	BIT(4)	/* Transmitter Enable */
62 #define ATMEL_I2SC_CR_TXDIS	BIT(5)	/* Transmitter Disable */
63 #define ATMEL_I2SC_CR_SWRST	BIT(7)	/* Software Reset */
64 
65 /*
66  * ---- Mode Register (Read/Write) ----
67  */
68 #define ATMEL_I2SC_MR_MODE_MASK		GENMASK(0, 0)
69 #define ATMEL_I2SC_MR_MODE_SLAVE	(0 << 0)
70 #define ATMEL_I2SC_MR_MODE_MASTER	(1 << 0)
71 
72 #define ATMEL_I2SC_MR_DATALENGTH_MASK		GENMASK(4, 2)
73 #define ATMEL_I2SC_MR_DATALENGTH_32_BITS	(0 << 2)
74 #define ATMEL_I2SC_MR_DATALENGTH_24_BITS	(1 << 2)
75 #define ATMEL_I2SC_MR_DATALENGTH_20_BITS	(2 << 2)
76 #define ATMEL_I2SC_MR_DATALENGTH_18_BITS	(3 << 2)
77 #define ATMEL_I2SC_MR_DATALENGTH_16_BITS	(4 << 2)
78 #define ATMEL_I2SC_MR_DATALENGTH_16_BITS_COMPACT	(5 << 2)
79 #define ATMEL_I2SC_MR_DATALENGTH_8_BITS		(6 << 2)
80 #define ATMEL_I2SC_MR_DATALENGTH_8_BITS_COMPACT	(7 << 2)
81 
82 #define ATMEL_I2SC_MR_FORMAT_MASK	GENMASK(7, 6)
83 #define ATMEL_I2SC_MR_FORMAT_I2S	(0 << 6)
84 #define ATMEL_I2SC_MR_FORMAT_LJ		(1 << 6)  /* Left Justified */
85 #define ATMEL_I2SC_MR_FORMAT_TDM	(2 << 6)
86 #define ATMEL_I2SC_MR_FORMAT_TDMLJ	(3 << 6)
87 
88 /* Left audio samples duplicated to right audio channel */
89 #define ATMEL_I2SC_MR_RXMONO		BIT(8)
90 
91 /* Receiver uses one DMA channel ... */
92 #define ATMEL_I2SC_MR_RXDMA_MASK	GENMASK(9, 9)
93 #define ATMEL_I2SC_MR_RXDMA_SINGLE	(0 << 9)  /* for all audio channels */
94 #define ATMEL_I2SC_MR_RXDMA_MULTIPLE	(1 << 9)  /* per audio channel */
95 
96 /* I2SDO output of I2SC is internally connected to I2SDI input */
97 #define ATMEL_I2SC_MR_RXLOOP		BIT(10)
98 
99 /* Left audio samples duplicated to right audio channel */
100 #define ATMEL_I2SC_MR_TXMONO		BIT(12)
101 
102 /* Transmitter uses one DMA channel ... */
103 #define ATMEL_I2SC_MR_TXDMA_MASK	GENMASK(13, 13)
104 #define ATMEL_I2SC_MR_TXDMA_SINGLE	(0 << 13)  /* for all audio channels */
105 #define ATMEL_I2SC_MR_TXDME_MULTIPLE	(1 << 13)  /* per audio channel */
106 
107 /* x sample transmitted when underrun */
108 #define ATMEL_I2SC_MR_TXSAME_MASK	GENMASK(14, 14)
109 #define ATMEL_I2SC_MR_TXSAME_ZERO	(0 << 14)  /* Zero sample */
110 #define ATMEL_I2SC_MR_TXSAME_PREVIOUS	(1 << 14)  /* Previous sample */
111 
112 /* Audio Clock to I2SC Master Clock ratio */
113 #define ATMEL_I2SC_MR_IMCKDIV_MASK	GENMASK(21, 16)
114 #define ATMEL_I2SC_MR_IMCKDIV(div) \
115 	(((div) << 16) & ATMEL_I2SC_MR_IMCKDIV_MASK)
116 
117 /* Master Clock to fs ratio */
118 #define ATMEL_I2SC_MR_IMCKFS_MASK	GENMASK(29, 24)
119 #define ATMEL_I2SC_MR_IMCKFS(fs) \
120 	(((fs) << 24) & ATMEL_I2SC_MR_IMCKFS_MASK)
121 
122 /* Master Clock mode */
123 #define ATMEL_I2SC_MR_IMCKMODE_MASK	GENMASK(30, 30)
124 /* 0: No master clock generated (selected clock drives I2SCK pin) */
125 #define ATMEL_I2SC_MR_IMCKMODE_I2SCK	(0 << 30)
126 /* 1: master clock generated (internally generated clock drives I2SMCK pin) */
127 #define ATMEL_I2SC_MR_IMCKMODE_I2SMCK	(1 << 30)
128 
129 /* Slot Width */
130 /* 0: slot is 32 bits wide for DATALENGTH = 18/20/24 bits. */
131 /* 1: slot is 24 bits wide for DATALENGTH = 18/20/24 bits. */
132 #define ATMEL_I2SC_MR_IWS		BIT(31)
133 
134 /*
135  * ---- Status Registers ----
136  */
137 #define ATMEL_I2SC_SR_RXEN	BIT(0)	/* Receiver Enabled */
138 #define ATMEL_I2SC_SR_RXRDY	BIT(1)	/* Receive Ready */
139 #define ATMEL_I2SC_SR_RXOR	BIT(2)	/* Receive Overrun */
140 
141 #define ATMEL_I2SC_SR_TXEN	BIT(4)	/* Transmitter Enabled */
142 #define ATMEL_I2SC_SR_TXRDY	BIT(5)	/* Transmit Ready */
143 #define ATMEL_I2SC_SR_TXUR	BIT(6)	/* Transmit Underrun */
144 
145 /* Receive Overrun Channel */
146 #define ATMEL_I2SC_SR_RXORCH_MASK	GENMASK(15, 8)
147 #define ATMEL_I2SC_SR_RXORCH(ch)	(1 << (((ch) & 0x7) + 8))
148 
149 /* Transmit Underrun Channel */
150 #define ATMEL_I2SC_SR_TXURCH_MASK	GENMASK(27, 20)
151 #define ATMEL_I2SC_SR_TXURCH(ch)	(1 << (((ch) & 0x7) + 20))
152 
153 /*
154  * ---- Interrupt Enable/Disable/Mask Registers ----
155  */
156 #define ATMEL_I2SC_INT_RXRDY	ATMEL_I2SC_SR_RXRDY
157 #define ATMEL_I2SC_INT_RXOR	ATMEL_I2SC_SR_RXOR
158 #define ATMEL_I2SC_INT_TXRDY	ATMEL_I2SC_SR_TXRDY
159 #define ATMEL_I2SC_INT_TXUR	ATMEL_I2SC_SR_TXUR
160 
161 static const struct regmap_config atmel_i2s_regmap_config = {
162 	.reg_bits = 32,
163 	.reg_stride = 4,
164 	.val_bits = 32,
165 	.max_register = ATMEL_I2SC_VERSION,
166 };
167 
168 struct atmel_i2s_gck_param {
169 	int		fs;
170 	unsigned long	mck;
171 	int		imckdiv;
172 	int		imckfs;
173 };
174 
175 #define I2S_MCK_12M288		12288000UL
176 #define I2S_MCK_11M2896		11289600UL
177 
178 /* mck = (32 * (imckfs+1) / (imckdiv+1)) * fs */
179 static const struct atmel_i2s_gck_param gck_params[] = {
180 	/* mck = 12.288MHz */
181 	{  8000, I2S_MCK_12M288, 0, 47},	/* mck = 1536 fs */
182 	{ 16000, I2S_MCK_12M288, 1, 47},	/* mck =  768 fs */
183 	{ 24000, I2S_MCK_12M288, 3, 63},	/* mck =  512 fs */
184 	{ 32000, I2S_MCK_12M288, 3, 47},	/* mck =  384 fs */
185 	{ 48000, I2S_MCK_12M288, 7, 63},	/* mck =  256 fs */
186 	{ 64000, I2S_MCK_12M288, 7, 47},	/* mck =  192 fs */
187 	{ 96000, I2S_MCK_12M288, 7, 31},	/* mck =  128 fs */
188 	{192000, I2S_MCK_12M288, 7, 15},	/* mck =   64 fs */
189 
190 	/* mck = 11.2896MHz */
191 	{ 11025, I2S_MCK_11M2896, 1, 63},	/* mck = 1024 fs */
192 	{ 22050, I2S_MCK_11M2896, 3, 63},	/* mck =  512 fs */
193 	{ 44100, I2S_MCK_11M2896, 7, 63},	/* mck =  256 fs */
194 	{ 88200, I2S_MCK_11M2896, 7, 31},	/* mck =  128 fs */
195 	{176400, I2S_MCK_11M2896, 7, 15},	/* mck =   64 fs */
196 };
197 
198 struct atmel_i2s_dev;
199 
200 struct atmel_i2s_caps {
201 	int	(*mck_init)(struct atmel_i2s_dev *, struct device_node *np);
202 };
203 
204 struct atmel_i2s_dev {
205 	struct device				*dev;
206 	struct regmap				*regmap;
207 	struct clk				*pclk;
208 	struct clk				*gclk;
209 	struct snd_dmaengine_dai_dma_data	playback;
210 	struct snd_dmaengine_dai_dma_data	capture;
211 	unsigned int				fmt;
212 	const struct atmel_i2s_gck_param	*gck_param;
213 	const struct atmel_i2s_caps		*caps;
214 };
215 
216 static irqreturn_t atmel_i2s_interrupt(int irq, void *dev_id)
217 {
218 	struct atmel_i2s_dev *dev = dev_id;
219 	unsigned int sr, imr, pending, ch, mask;
220 	irqreturn_t ret = IRQ_NONE;
221 
222 	regmap_read(dev->regmap, ATMEL_I2SC_SR, &sr);
223 	regmap_read(dev->regmap, ATMEL_I2SC_IMR, &imr);
224 	pending = sr & imr;
225 
226 	if (!pending)
227 		return IRQ_NONE;
228 
229 	if (pending & ATMEL_I2SC_INT_RXOR) {
230 		mask = ATMEL_I2SC_SR_RXOR;
231 
232 		for (ch = 0; ch < ATMEL_I2SC_MAX_TDM_CHANNELS; ++ch) {
233 			if (sr & ATMEL_I2SC_SR_RXORCH(ch)) {
234 				mask |= ATMEL_I2SC_SR_RXORCH(ch);
235 				dev_err(dev->dev,
236 					"RX overrun on channel %d\n", ch);
237 			}
238 		}
239 		regmap_write(dev->regmap, ATMEL_I2SC_SCR, mask);
240 		ret = IRQ_HANDLED;
241 	}
242 
243 	if (pending & ATMEL_I2SC_INT_TXUR) {
244 		mask = ATMEL_I2SC_SR_TXUR;
245 
246 		for (ch = 0; ch < ATMEL_I2SC_MAX_TDM_CHANNELS; ++ch) {
247 			if (sr & ATMEL_I2SC_SR_TXURCH(ch)) {
248 				mask |= ATMEL_I2SC_SR_TXURCH(ch);
249 				dev_err(dev->dev,
250 					"TX underrun on channel %d\n", ch);
251 			}
252 		}
253 		regmap_write(dev->regmap, ATMEL_I2SC_SCR, mask);
254 		ret = IRQ_HANDLED;
255 	}
256 
257 	return ret;
258 }
259 
260 #define ATMEL_I2S_RATES		SNDRV_PCM_RATE_8000_192000
261 
262 #define ATMEL_I2S_FORMATS	(SNDRV_PCM_FMTBIT_S8 |		\
263 				 SNDRV_PCM_FMTBIT_S16_LE |	\
264 				 SNDRV_PCM_FMTBIT_S18_3LE |	\
265 				 SNDRV_PCM_FMTBIT_S20_3LE |	\
266 				 SNDRV_PCM_FMTBIT_S24_3LE |	\
267 				 SNDRV_PCM_FMTBIT_S24_LE |	\
268 				 SNDRV_PCM_FMTBIT_S32_LE)
269 
270 static int atmel_i2s_set_dai_fmt(struct snd_soc_dai *dai, unsigned int fmt)
271 {
272 	struct atmel_i2s_dev *dev = snd_soc_dai_get_drvdata(dai);
273 
274 	dev->fmt = fmt;
275 	return 0;
276 }
277 
278 static int atmel_i2s_prepare(struct snd_pcm_substream *substream,
279 			     struct snd_soc_dai *dai)
280 {
281 	struct atmel_i2s_dev *dev = snd_soc_dai_get_drvdata(dai);
282 	bool is_playback = (substream->stream == SNDRV_PCM_STREAM_PLAYBACK);
283 	unsigned int rhr, sr = 0;
284 
285 	if (is_playback) {
286 		regmap_read(dev->regmap, ATMEL_I2SC_SR, &sr);
287 		if (sr & ATMEL_I2SC_SR_RXRDY) {
288 			/*
289 			 * The RX Ready flag should not be set. However if here,
290 			 * we flush (read) the Receive Holding Register to start
291 			 * from a clean state.
292 			 */
293 			dev_dbg(dev->dev, "RXRDY is set\n");
294 			regmap_read(dev->regmap, ATMEL_I2SC_RHR, &rhr);
295 		}
296 	}
297 
298 	return 0;
299 }
300 
301 static int atmel_i2s_get_gck_param(struct atmel_i2s_dev *dev, int fs)
302 {
303 	int i, best;
304 
305 	if (!dev->gclk) {
306 		dev_err(dev->dev, "cannot generate the I2S Master Clock\n");
307 		return -EINVAL;
308 	}
309 
310 	/*
311 	 * Find the best possible settings to generate the I2S Master Clock
312 	 * from the PLL Audio.
313 	 */
314 	dev->gck_param = NULL;
315 	best = INT_MAX;
316 	for (i = 0; i < ARRAY_SIZE(gck_params); ++i) {
317 		const struct atmel_i2s_gck_param *gck_param = &gck_params[i];
318 		int val = abs(fs - gck_param->fs);
319 
320 		if (val < best) {
321 			best = val;
322 			dev->gck_param = gck_param;
323 		}
324 	}
325 
326 	return 0;
327 }
328 
329 static int atmel_i2s_hw_params(struct snd_pcm_substream *substream,
330 			       struct snd_pcm_hw_params *params,
331 			       struct snd_soc_dai *dai)
332 {
333 	struct atmel_i2s_dev *dev = snd_soc_dai_get_drvdata(dai);
334 	bool is_playback = (substream->stream == SNDRV_PCM_STREAM_PLAYBACK);
335 	unsigned int mr = 0;
336 	int ret;
337 
338 	switch (dev->fmt & SND_SOC_DAIFMT_FORMAT_MASK) {
339 	case SND_SOC_DAIFMT_I2S:
340 		mr |= ATMEL_I2SC_MR_FORMAT_I2S;
341 		break;
342 
343 	default:
344 		dev_err(dev->dev, "unsupported bus format\n");
345 		return -EINVAL;
346 	}
347 
348 	switch (dev->fmt & SND_SOC_DAIFMT_MASTER_MASK) {
349 	case SND_SOC_DAIFMT_CBS_CFS:
350 		/* codec is slave, so cpu is master */
351 		mr |= ATMEL_I2SC_MR_MODE_MASTER;
352 		ret = atmel_i2s_get_gck_param(dev, params_rate(params));
353 		if (ret)
354 			return ret;
355 		break;
356 
357 	case SND_SOC_DAIFMT_CBM_CFM:
358 		/* codec is master, so cpu is slave */
359 		mr |= ATMEL_I2SC_MR_MODE_SLAVE;
360 		dev->gck_param = NULL;
361 		break;
362 
363 	default:
364 		dev_err(dev->dev, "unsupported master/slave mode\n");
365 		return -EINVAL;
366 	}
367 
368 	switch (params_channels(params)) {
369 	case 1:
370 		if (is_playback)
371 			mr |= ATMEL_I2SC_MR_TXMONO;
372 		else
373 			mr |= ATMEL_I2SC_MR_RXMONO;
374 		break;
375 	case 2:
376 		break;
377 	default:
378 		dev_err(dev->dev, "unsupported number of audio channels\n");
379 		return -EINVAL;
380 	}
381 
382 	switch (params_format(params)) {
383 	case SNDRV_PCM_FORMAT_S8:
384 		mr |= ATMEL_I2SC_MR_DATALENGTH_8_BITS;
385 		break;
386 
387 	case SNDRV_PCM_FORMAT_S16_LE:
388 		mr |= ATMEL_I2SC_MR_DATALENGTH_16_BITS;
389 		break;
390 
391 	case SNDRV_PCM_FORMAT_S18_3LE:
392 		mr |= ATMEL_I2SC_MR_DATALENGTH_18_BITS | ATMEL_I2SC_MR_IWS;
393 		break;
394 
395 	case SNDRV_PCM_FORMAT_S20_3LE:
396 		mr |= ATMEL_I2SC_MR_DATALENGTH_20_BITS | ATMEL_I2SC_MR_IWS;
397 		break;
398 
399 	case SNDRV_PCM_FORMAT_S24_3LE:
400 		mr |= ATMEL_I2SC_MR_DATALENGTH_24_BITS | ATMEL_I2SC_MR_IWS;
401 		break;
402 
403 	case SNDRV_PCM_FORMAT_S24_LE:
404 		mr |= ATMEL_I2SC_MR_DATALENGTH_24_BITS;
405 		break;
406 
407 	case SNDRV_PCM_FORMAT_S32_LE:
408 		mr |= ATMEL_I2SC_MR_DATALENGTH_32_BITS;
409 		break;
410 
411 	default:
412 		dev_err(dev->dev, "unsupported size/endianness for audio samples\n");
413 		return -EINVAL;
414 	}
415 
416 	return regmap_write(dev->regmap, ATMEL_I2SC_MR, mr);
417 }
418 
419 static int atmel_i2s_switch_mck_generator(struct atmel_i2s_dev *dev,
420 					  bool enabled)
421 {
422 	unsigned int mr, mr_mask;
423 	unsigned long gclk_rate;
424 	int ret;
425 
426 	mr = 0;
427 	mr_mask = (ATMEL_I2SC_MR_IMCKDIV_MASK |
428 		   ATMEL_I2SC_MR_IMCKFS_MASK |
429 		   ATMEL_I2SC_MR_IMCKMODE_MASK);
430 
431 	if (!enabled) {
432 		/* Disable the I2S Master Clock generator. */
433 		ret = regmap_write(dev->regmap, ATMEL_I2SC_CR,
434 				   ATMEL_I2SC_CR_CKDIS);
435 		if (ret)
436 			return ret;
437 
438 		/* Reset the I2S Master Clock generator settings. */
439 		ret = regmap_update_bits(dev->regmap, ATMEL_I2SC_MR,
440 					 mr_mask, mr);
441 		if (ret)
442 			return ret;
443 
444 		/* Disable/unprepare the PMC generated clock. */
445 		clk_disable_unprepare(dev->gclk);
446 
447 		return 0;
448 	}
449 
450 	if (!dev->gck_param)
451 		return -EINVAL;
452 
453 	gclk_rate = dev->gck_param->mck * (dev->gck_param->imckdiv + 1);
454 
455 	ret = clk_set_rate(dev->gclk, gclk_rate);
456 	if (ret)
457 		return ret;
458 
459 	ret = clk_prepare_enable(dev->gclk);
460 	if (ret)
461 		return ret;
462 
463 	/* Update the Mode Register to generate the I2S Master Clock. */
464 	mr |= ATMEL_I2SC_MR_IMCKDIV(dev->gck_param->imckdiv);
465 	mr |= ATMEL_I2SC_MR_IMCKFS(dev->gck_param->imckfs);
466 	mr |= ATMEL_I2SC_MR_IMCKMODE_I2SMCK;
467 	ret = regmap_update_bits(dev->regmap, ATMEL_I2SC_MR, mr_mask, mr);
468 	if (ret)
469 		return ret;
470 
471 	/* Finally enable the I2S Master Clock generator. */
472 	return regmap_write(dev->regmap, ATMEL_I2SC_CR,
473 			    ATMEL_I2SC_CR_CKEN);
474 }
475 
476 static int atmel_i2s_trigger(struct snd_pcm_substream *substream, int cmd,
477 			     struct snd_soc_dai *dai)
478 {
479 	struct atmel_i2s_dev *dev = snd_soc_dai_get_drvdata(dai);
480 	bool is_playback = (substream->stream == SNDRV_PCM_STREAM_PLAYBACK);
481 	bool is_master, mck_enabled;
482 	unsigned int cr, mr;
483 	int err;
484 
485 	switch (cmd) {
486 	case SNDRV_PCM_TRIGGER_START:
487 	case SNDRV_PCM_TRIGGER_RESUME:
488 	case SNDRV_PCM_TRIGGER_PAUSE_RELEASE:
489 		cr = is_playback ? ATMEL_I2SC_CR_TXEN : ATMEL_I2SC_CR_RXEN;
490 		mck_enabled = true;
491 		break;
492 	case SNDRV_PCM_TRIGGER_STOP:
493 	case SNDRV_PCM_TRIGGER_SUSPEND:
494 	case SNDRV_PCM_TRIGGER_PAUSE_PUSH:
495 		cr = is_playback ? ATMEL_I2SC_CR_TXDIS : ATMEL_I2SC_CR_RXDIS;
496 		mck_enabled = false;
497 		break;
498 	default:
499 		return -EINVAL;
500 	}
501 
502 	/* Read the Mode Register to retrieve the master/slave state. */
503 	err = regmap_read(dev->regmap, ATMEL_I2SC_MR, &mr);
504 	if (err)
505 		return err;
506 	is_master = (mr & ATMEL_I2SC_MR_MODE_MASK) == ATMEL_I2SC_MR_MODE_MASTER;
507 
508 	/* If master starts, enable the audio clock. */
509 	if (is_master && mck_enabled)
510 		err = atmel_i2s_switch_mck_generator(dev, true);
511 	if (err)
512 		return err;
513 
514 	err = regmap_write(dev->regmap, ATMEL_I2SC_CR, cr);
515 	if (err)
516 		return err;
517 
518 	/* If master stops, disable the audio clock. */
519 	if (is_master && !mck_enabled)
520 		err = atmel_i2s_switch_mck_generator(dev, false);
521 
522 	return err;
523 }
524 
525 static const struct snd_soc_dai_ops atmel_i2s_dai_ops = {
526 	.prepare	= atmel_i2s_prepare,
527 	.trigger	= atmel_i2s_trigger,
528 	.hw_params	= atmel_i2s_hw_params,
529 	.set_fmt	= atmel_i2s_set_dai_fmt,
530 };
531 
532 static int atmel_i2s_dai_probe(struct snd_soc_dai *dai)
533 {
534 	struct atmel_i2s_dev *dev = snd_soc_dai_get_drvdata(dai);
535 
536 	snd_soc_dai_init_dma_data(dai, &dev->playback, &dev->capture);
537 	return 0;
538 }
539 
540 static struct snd_soc_dai_driver atmel_i2s_dai = {
541 	.probe	= atmel_i2s_dai_probe,
542 	.playback = {
543 		.channels_min = 1,
544 		.channels_max = 2,
545 		.rates = ATMEL_I2S_RATES,
546 		.formats = ATMEL_I2S_FORMATS,
547 	},
548 	.capture = {
549 		.channels_min = 1,
550 		.channels_max = 2,
551 		.rates = ATMEL_I2S_RATES,
552 		.formats = ATMEL_I2S_FORMATS,
553 	},
554 	.ops = &atmel_i2s_dai_ops,
555 	.symmetric_rates = 1,
556 };
557 
558 static const struct snd_soc_component_driver atmel_i2s_component = {
559 	.name	= "atmel-i2s",
560 };
561 
562 static int atmel_i2s_sama5d2_mck_init(struct atmel_i2s_dev *dev,
563 				      struct device_node *np)
564 {
565 	struct clk *muxclk;
566 	int err;
567 
568 	if (!dev->gclk)
569 		return 0;
570 
571 	/* muxclk is optional, so we return error for probe defer only */
572 	muxclk = devm_clk_get(dev->dev, "muxclk");
573 	if (IS_ERR(muxclk)) {
574 		err = PTR_ERR(muxclk);
575 		if (err == -EPROBE_DEFER)
576 			return -EPROBE_DEFER;
577 		dev_warn(dev->dev,
578 			 "failed to get the I2S clock control: %d\n", err);
579 		return 0;
580 	}
581 
582 	return clk_set_parent(muxclk, dev->gclk);
583 }
584 
585 static const struct atmel_i2s_caps atmel_i2s_sama5d2_caps = {
586 	.mck_init = atmel_i2s_sama5d2_mck_init,
587 };
588 
589 static const struct of_device_id atmel_i2s_dt_ids[] = {
590 	{
591 		.compatible = "atmel,sama5d2-i2s",
592 		.data = (void *)&atmel_i2s_sama5d2_caps,
593 	},
594 
595 	{ /* sentinel */ }
596 };
597 
598 MODULE_DEVICE_TABLE(of, atmel_i2s_dt_ids);
599 
600 static int atmel_i2s_probe(struct platform_device *pdev)
601 {
602 	struct device_node *np = pdev->dev.of_node;
603 	const struct of_device_id *match;
604 	struct atmel_i2s_dev *dev;
605 	struct resource *mem;
606 	struct regmap *regmap;
607 	void __iomem *base;
608 	int irq;
609 	int err = -ENXIO;
610 	unsigned int pcm_flags = 0;
611 	unsigned int version;
612 
613 	/* Get memory for driver data. */
614 	dev = devm_kzalloc(&pdev->dev, sizeof(*dev), GFP_KERNEL);
615 	if (!dev)
616 		return -ENOMEM;
617 
618 	/* Get hardware capabilities. */
619 	match = of_match_node(atmel_i2s_dt_ids, np);
620 	if (match)
621 		dev->caps = match->data;
622 
623 	/* Map I/O registers. */
624 	mem = platform_get_resource(pdev, IORESOURCE_MEM, 0);
625 	base = devm_ioremap_resource(&pdev->dev, mem);
626 	if (IS_ERR(base))
627 		return PTR_ERR(base);
628 
629 	regmap = devm_regmap_init_mmio(&pdev->dev, base,
630 				       &atmel_i2s_regmap_config);
631 	if (IS_ERR(regmap))
632 		return PTR_ERR(regmap);
633 
634 	/* Request IRQ. */
635 	irq = platform_get_irq(pdev, 0);
636 	if (irq < 0)
637 		return irq;
638 
639 	err = devm_request_irq(&pdev->dev, irq, atmel_i2s_interrupt, 0,
640 			       dev_name(&pdev->dev), dev);
641 	if (err)
642 		return err;
643 
644 	/* Get the peripheral clock. */
645 	dev->pclk = devm_clk_get(&pdev->dev, "pclk");
646 	if (IS_ERR(dev->pclk)) {
647 		err = PTR_ERR(dev->pclk);
648 		dev_err(&pdev->dev,
649 			"failed to get the peripheral clock: %d\n", err);
650 		return err;
651 	}
652 
653 	/* Get audio clock to generate the I2S Master Clock (I2S_MCK) */
654 	dev->gclk = devm_clk_get(&pdev->dev, "gclk");
655 	if (IS_ERR(dev->gclk)) {
656 		if (PTR_ERR(dev->gclk) == -EPROBE_DEFER)
657 			return -EPROBE_DEFER;
658 		/* Master Mode not supported */
659 		dev->gclk = NULL;
660 	}
661 	dev->dev = &pdev->dev;
662 	dev->regmap = regmap;
663 	platform_set_drvdata(pdev, dev);
664 
665 	/* Do hardware specific settings to initialize I2S_MCK generator */
666 	if (dev->caps && dev->caps->mck_init) {
667 		err = dev->caps->mck_init(dev, np);
668 		if (err)
669 			return err;
670 	}
671 
672 	/* Enable the peripheral clock. */
673 	err = clk_prepare_enable(dev->pclk);
674 	if (err)
675 		return err;
676 
677 	/* Get IP version. */
678 	regmap_read(dev->regmap, ATMEL_I2SC_VERSION, &version);
679 	dev_info(&pdev->dev, "hw version: %#x\n", version);
680 
681 	/* Enable error interrupts. */
682 	regmap_write(dev->regmap, ATMEL_I2SC_IER,
683 		     ATMEL_I2SC_INT_RXOR | ATMEL_I2SC_INT_TXUR);
684 
685 	err = devm_snd_soc_register_component(&pdev->dev,
686 					      &atmel_i2s_component,
687 					      &atmel_i2s_dai, 1);
688 	if (err) {
689 		dev_err(&pdev->dev, "failed to register DAI: %d\n", err);
690 		clk_disable_unprepare(dev->pclk);
691 		return err;
692 	}
693 
694 	/* Prepare DMA config. */
695 	dev->playback.addr	= (dma_addr_t)mem->start + ATMEL_I2SC_THR;
696 	dev->playback.maxburst	= 1;
697 	dev->capture.addr	= (dma_addr_t)mem->start + ATMEL_I2SC_RHR;
698 	dev->capture.maxburst	= 1;
699 
700 	if (of_property_match_string(np, "dma-names", "rx-tx") == 0)
701 		pcm_flags |= SND_DMAENGINE_PCM_FLAG_HALF_DUPLEX;
702 	err = devm_snd_dmaengine_pcm_register(&pdev->dev, NULL, pcm_flags);
703 	if (err) {
704 		dev_err(&pdev->dev, "failed to register PCM: %d\n", err);
705 		clk_disable_unprepare(dev->pclk);
706 		return err;
707 	}
708 
709 	return 0;
710 }
711 
712 static int atmel_i2s_remove(struct platform_device *pdev)
713 {
714 	struct atmel_i2s_dev *dev = platform_get_drvdata(pdev);
715 
716 	clk_disable_unprepare(dev->pclk);
717 
718 	return 0;
719 }
720 
721 static struct platform_driver atmel_i2s_driver = {
722 	.driver		= {
723 		.name	= "atmel_i2s",
724 		.of_match_table	= of_match_ptr(atmel_i2s_dt_ids),
725 	},
726 	.probe		= atmel_i2s_probe,
727 	.remove		= atmel_i2s_remove,
728 };
729 module_platform_driver(atmel_i2s_driver);
730 
731 MODULE_DESCRIPTION("Atmel I2S Controller driver");
732 MODULE_AUTHOR("Cyrille Pitchen <cyrille.pitchen@atmel.com>");
733 MODULE_LICENSE("GPL v2");
734