xref: /linux/sound/soc/atmel/atmel-i2s.c (revision be239684b18e1cdcafcf8c7face4a2f562c745ad)
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 #define I2S_MCK_6M144		6144000UL
167 
168 /* mck = (32 * (imckfs+1) / (imckdiv+1)) * fs */
169 static const struct atmel_i2s_gck_param gck_params[] = {
170 	/* mck = 6.144Mhz */
171 	{  8000, I2S_MCK_6M144,  1, 47},	/* mck =  768 fs */
172 
173 	/* mck = 12.288MHz */
174 	{ 16000, I2S_MCK_12M288, 1, 47},	/* mck =  768 fs */
175 	{ 24000, I2S_MCK_12M288, 3, 63},	/* mck =  512 fs */
176 	{ 32000, I2S_MCK_12M288, 3, 47},	/* mck =  384 fs */
177 	{ 48000, I2S_MCK_12M288, 7, 63},	/* mck =  256 fs */
178 	{ 64000, I2S_MCK_12M288, 7, 47},	/* mck =  192 fs */
179 	{ 96000, I2S_MCK_12M288, 7, 31},	/* mck =  128 fs */
180 	{192000, I2S_MCK_12M288, 7, 15},	/* mck =   64 fs */
181 
182 	/* mck = 11.2896MHz */
183 	{ 11025, I2S_MCK_11M2896, 1, 63},	/* mck = 1024 fs */
184 	{ 22050, I2S_MCK_11M2896, 3, 63},	/* mck =  512 fs */
185 	{ 44100, I2S_MCK_11M2896, 7, 63},	/* mck =  256 fs */
186 	{ 88200, I2S_MCK_11M2896, 7, 31},	/* mck =  128 fs */
187 	{176400, I2S_MCK_11M2896, 7, 15},	/* mck =   64 fs */
188 };
189 
190 struct atmel_i2s_dev;
191 
192 struct atmel_i2s_caps {
193 	int	(*mck_init)(struct atmel_i2s_dev *, struct device_node *np);
194 };
195 
196 struct atmel_i2s_dev {
197 	struct device				*dev;
198 	struct regmap				*regmap;
199 	struct clk				*pclk;
200 	struct clk				*gclk;
201 	struct snd_dmaengine_dai_dma_data	playback;
202 	struct snd_dmaengine_dai_dma_data	capture;
203 	unsigned int				fmt;
204 	const struct atmel_i2s_gck_param	*gck_param;
205 	const struct atmel_i2s_caps		*caps;
206 	int					clk_use_no;
207 };
208 
209 static irqreturn_t atmel_i2s_interrupt(int irq, void *dev_id)
210 {
211 	struct atmel_i2s_dev *dev = dev_id;
212 	unsigned int sr, imr, pending, ch, mask;
213 	irqreturn_t ret = IRQ_NONE;
214 
215 	regmap_read(dev->regmap, ATMEL_I2SC_SR, &sr);
216 	regmap_read(dev->regmap, ATMEL_I2SC_IMR, &imr);
217 	pending = sr & imr;
218 
219 	if (!pending)
220 		return IRQ_NONE;
221 
222 	if (pending & ATMEL_I2SC_INT_RXOR) {
223 		mask = ATMEL_I2SC_SR_RXOR;
224 
225 		for (ch = 0; ch < ATMEL_I2SC_MAX_TDM_CHANNELS; ++ch) {
226 			if (sr & ATMEL_I2SC_SR_RXORCH(ch)) {
227 				mask |= ATMEL_I2SC_SR_RXORCH(ch);
228 				dev_err(dev->dev,
229 					"RX overrun on channel %d\n", ch);
230 			}
231 		}
232 		regmap_write(dev->regmap, ATMEL_I2SC_SCR, mask);
233 		ret = IRQ_HANDLED;
234 	}
235 
236 	if (pending & ATMEL_I2SC_INT_TXUR) {
237 		mask = ATMEL_I2SC_SR_TXUR;
238 
239 		for (ch = 0; ch < ATMEL_I2SC_MAX_TDM_CHANNELS; ++ch) {
240 			if (sr & ATMEL_I2SC_SR_TXURCH(ch)) {
241 				mask |= ATMEL_I2SC_SR_TXURCH(ch);
242 				dev_err(dev->dev,
243 					"TX underrun on channel %d\n", ch);
244 			}
245 		}
246 		regmap_write(dev->regmap, ATMEL_I2SC_SCR, mask);
247 		ret = IRQ_HANDLED;
248 	}
249 
250 	return ret;
251 }
252 
253 #define ATMEL_I2S_RATES		SNDRV_PCM_RATE_8000_192000
254 
255 #define ATMEL_I2S_FORMATS	(SNDRV_PCM_FMTBIT_S8 |		\
256 				 SNDRV_PCM_FMTBIT_S16_LE |	\
257 				 SNDRV_PCM_FMTBIT_S18_3LE |	\
258 				 SNDRV_PCM_FMTBIT_S20_3LE |	\
259 				 SNDRV_PCM_FMTBIT_S24_3LE |	\
260 				 SNDRV_PCM_FMTBIT_S24_LE |	\
261 				 SNDRV_PCM_FMTBIT_S32_LE)
262 
263 static int atmel_i2s_set_dai_fmt(struct snd_soc_dai *dai, unsigned int fmt)
264 {
265 	struct atmel_i2s_dev *dev = snd_soc_dai_get_drvdata(dai);
266 
267 	dev->fmt = fmt;
268 	return 0;
269 }
270 
271 static int atmel_i2s_prepare(struct snd_pcm_substream *substream,
272 			     struct snd_soc_dai *dai)
273 {
274 	struct atmel_i2s_dev *dev = snd_soc_dai_get_drvdata(dai);
275 	bool is_playback = (substream->stream == SNDRV_PCM_STREAM_PLAYBACK);
276 	unsigned int rhr, sr = 0;
277 
278 	if (is_playback) {
279 		regmap_read(dev->regmap, ATMEL_I2SC_SR, &sr);
280 		if (sr & ATMEL_I2SC_SR_RXRDY) {
281 			/*
282 			 * The RX Ready flag should not be set. However if here,
283 			 * we flush (read) the Receive Holding Register to start
284 			 * from a clean state.
285 			 */
286 			dev_dbg(dev->dev, "RXRDY is set\n");
287 			regmap_read(dev->regmap, ATMEL_I2SC_RHR, &rhr);
288 		}
289 	}
290 
291 	return 0;
292 }
293 
294 static int atmel_i2s_get_gck_param(struct atmel_i2s_dev *dev, int fs)
295 {
296 	int i, best;
297 
298 	if (!dev->gclk) {
299 		dev_err(dev->dev, "cannot generate the I2S Master Clock\n");
300 		return -EINVAL;
301 	}
302 
303 	/*
304 	 * Find the best possible settings to generate the I2S Master Clock
305 	 * from the PLL Audio.
306 	 */
307 	dev->gck_param = NULL;
308 	best = INT_MAX;
309 	for (i = 0; i < ARRAY_SIZE(gck_params); ++i) {
310 		const struct atmel_i2s_gck_param *gck_param = &gck_params[i];
311 		int val = abs(fs - gck_param->fs);
312 
313 		if (val < best) {
314 			best = val;
315 			dev->gck_param = gck_param;
316 		}
317 	}
318 
319 	return 0;
320 }
321 
322 static int atmel_i2s_hw_params(struct snd_pcm_substream *substream,
323 			       struct snd_pcm_hw_params *params,
324 			       struct snd_soc_dai *dai)
325 {
326 	struct atmel_i2s_dev *dev = snd_soc_dai_get_drvdata(dai);
327 	bool is_playback = (substream->stream == SNDRV_PCM_STREAM_PLAYBACK);
328 	unsigned int mr = 0, mr_mask;
329 	int ret;
330 
331 	mr_mask = ATMEL_I2SC_MR_FORMAT_MASK | ATMEL_I2SC_MR_MODE_MASK |
332 		ATMEL_I2SC_MR_DATALENGTH_MASK;
333 	if (is_playback)
334 		mr_mask |= ATMEL_I2SC_MR_TXMONO;
335 	else
336 		mr_mask |= ATMEL_I2SC_MR_RXMONO;
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_CLOCK_PROVIDER_MASK) {
349 	case SND_SOC_DAIFMT_BP_FP:
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_BC_FC:
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_update_bits(dev->regmap, ATMEL_I2SC_MR, mr_mask, 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 		if (!dev->clk_use_no) {
511 			err = atmel_i2s_switch_mck_generator(dev, true);
512 			if (err)
513 				return err;
514 		}
515 		dev->clk_use_no++;
516 	}
517 
518 	err = regmap_write(dev->regmap, ATMEL_I2SC_CR, cr);
519 	if (err)
520 		return err;
521 
522 	/* If master stops, disable the audio clock. */
523 	if (is_master && !mck_enabled) {
524 		if (dev->clk_use_no == 1) {
525 			err = atmel_i2s_switch_mck_generator(dev, false);
526 			if (err)
527 				return err;
528 		}
529 		dev->clk_use_no--;
530 	}
531 
532 	return err;
533 }
534 
535 static int atmel_i2s_dai_probe(struct snd_soc_dai *dai)
536 {
537 	struct atmel_i2s_dev *dev = snd_soc_dai_get_drvdata(dai);
538 
539 	snd_soc_dai_init_dma_data(dai, &dev->playback, &dev->capture);
540 	return 0;
541 }
542 
543 static const struct snd_soc_dai_ops atmel_i2s_dai_ops = {
544 	.probe		= atmel_i2s_dai_probe,
545 	.prepare	= atmel_i2s_prepare,
546 	.trigger	= atmel_i2s_trigger,
547 	.hw_params	= atmel_i2s_hw_params,
548 	.set_fmt	= atmel_i2s_set_dai_fmt,
549 };
550 
551 static struct snd_soc_dai_driver atmel_i2s_dai = {
552 	.playback = {
553 		.channels_min = 1,
554 		.channels_max = 2,
555 		.rates = ATMEL_I2S_RATES,
556 		.formats = ATMEL_I2S_FORMATS,
557 	},
558 	.capture = {
559 		.channels_min = 1,
560 		.channels_max = 2,
561 		.rates = ATMEL_I2S_RATES,
562 		.formats = ATMEL_I2S_FORMATS,
563 	},
564 	.ops = &atmel_i2s_dai_ops,
565 	.symmetric_rate = 1,
566 	.symmetric_sample_bits = 1,
567 };
568 
569 static const struct snd_soc_component_driver atmel_i2s_component = {
570 	.name			= "atmel-i2s",
571 	.legacy_dai_naming	= 1,
572 };
573 
574 static int atmel_i2s_sama5d2_mck_init(struct atmel_i2s_dev *dev,
575 				      struct device_node *np)
576 {
577 	struct clk *muxclk;
578 	int err;
579 
580 	if (!dev->gclk)
581 		return 0;
582 
583 	/* muxclk is optional, so we return error for probe defer only */
584 	muxclk = devm_clk_get(dev->dev, "muxclk");
585 	if (IS_ERR(muxclk)) {
586 		err = PTR_ERR(muxclk);
587 		if (err == -EPROBE_DEFER)
588 			return -EPROBE_DEFER;
589 		dev_dbg(dev->dev,
590 			"failed to get the I2S clock control: %d\n", err);
591 		return 0;
592 	}
593 
594 	return clk_set_parent(muxclk, dev->gclk);
595 }
596 
597 static const struct atmel_i2s_caps atmel_i2s_sama5d2_caps = {
598 	.mck_init = atmel_i2s_sama5d2_mck_init,
599 };
600 
601 static const struct of_device_id atmel_i2s_dt_ids[] = {
602 	{
603 		.compatible = "atmel,sama5d2-i2s",
604 		.data = (void *)&atmel_i2s_sama5d2_caps,
605 	},
606 
607 	{ /* sentinel */ }
608 };
609 
610 MODULE_DEVICE_TABLE(of, atmel_i2s_dt_ids);
611 
612 static int atmel_i2s_probe(struct platform_device *pdev)
613 {
614 	struct device_node *np = pdev->dev.of_node;
615 	const struct of_device_id *match;
616 	struct atmel_i2s_dev *dev;
617 	struct resource *mem;
618 	struct regmap *regmap;
619 	void __iomem *base;
620 	int irq;
621 	int err;
622 	unsigned int pcm_flags = 0;
623 	unsigned int version;
624 
625 	/* Get memory for driver data. */
626 	dev = devm_kzalloc(&pdev->dev, sizeof(*dev), GFP_KERNEL);
627 	if (!dev)
628 		return -ENOMEM;
629 
630 	/* Get hardware capabilities. */
631 	match = of_match_node(atmel_i2s_dt_ids, np);
632 	if (match)
633 		dev->caps = match->data;
634 
635 	/* Map I/O registers. */
636 	base = devm_platform_get_and_ioremap_resource(pdev, 0, &mem);
637 	if (IS_ERR(base))
638 		return PTR_ERR(base);
639 
640 	regmap = devm_regmap_init_mmio(&pdev->dev, base,
641 				       &atmel_i2s_regmap_config);
642 	if (IS_ERR(regmap))
643 		return PTR_ERR(regmap);
644 
645 	/* Request IRQ. */
646 	irq = platform_get_irq(pdev, 0);
647 	if (irq < 0)
648 		return irq;
649 
650 	err = devm_request_irq(&pdev->dev, irq, atmel_i2s_interrupt, 0,
651 			       dev_name(&pdev->dev), dev);
652 	if (err)
653 		return err;
654 
655 	/* Get the peripheral clock. */
656 	dev->pclk = devm_clk_get(&pdev->dev, "pclk");
657 	if (IS_ERR(dev->pclk)) {
658 		err = PTR_ERR(dev->pclk);
659 		dev_err(&pdev->dev,
660 			"failed to get the peripheral clock: %d\n", err);
661 		return err;
662 	}
663 
664 	/* Get audio clock to generate the I2S Master Clock (I2S_MCK) */
665 	dev->gclk = devm_clk_get(&pdev->dev, "gclk");
666 	if (IS_ERR(dev->gclk)) {
667 		if (PTR_ERR(dev->gclk) == -EPROBE_DEFER)
668 			return -EPROBE_DEFER;
669 		/* Master Mode not supported */
670 		dev->gclk = NULL;
671 	}
672 	dev->dev = &pdev->dev;
673 	dev->regmap = regmap;
674 	platform_set_drvdata(pdev, dev);
675 
676 	/* Do hardware specific settings to initialize I2S_MCK generator */
677 	if (dev->caps && dev->caps->mck_init) {
678 		err = dev->caps->mck_init(dev, np);
679 		if (err)
680 			return err;
681 	}
682 
683 	/* Enable the peripheral clock. */
684 	err = clk_prepare_enable(dev->pclk);
685 	if (err)
686 		return err;
687 
688 	/* Get IP version. */
689 	regmap_read(dev->regmap, ATMEL_I2SC_VERSION, &version);
690 	dev_info(&pdev->dev, "hw version: %#x\n", version);
691 
692 	/* Enable error interrupts. */
693 	regmap_write(dev->regmap, ATMEL_I2SC_IER,
694 		     ATMEL_I2SC_INT_RXOR | ATMEL_I2SC_INT_TXUR);
695 
696 	err = devm_snd_soc_register_component(&pdev->dev,
697 					      &atmel_i2s_component,
698 					      &atmel_i2s_dai, 1);
699 	if (err) {
700 		dev_err(&pdev->dev, "failed to register DAI: %d\n", err);
701 		clk_disable_unprepare(dev->pclk);
702 		return err;
703 	}
704 
705 	/* Prepare DMA config. */
706 	dev->playback.addr	= (dma_addr_t)mem->start + ATMEL_I2SC_THR;
707 	dev->playback.maxburst	= 1;
708 	dev->capture.addr	= (dma_addr_t)mem->start + ATMEL_I2SC_RHR;
709 	dev->capture.maxburst	= 1;
710 
711 	if (of_property_match_string(np, "dma-names", "rx-tx") == 0)
712 		pcm_flags |= SND_DMAENGINE_PCM_FLAG_HALF_DUPLEX;
713 	err = devm_snd_dmaengine_pcm_register(&pdev->dev, NULL, pcm_flags);
714 	if (err) {
715 		dev_err(&pdev->dev, "failed to register PCM: %d\n", err);
716 		clk_disable_unprepare(dev->pclk);
717 		return err;
718 	}
719 
720 	return 0;
721 }
722 
723 static void atmel_i2s_remove(struct platform_device *pdev)
724 {
725 	struct atmel_i2s_dev *dev = platform_get_drvdata(pdev);
726 
727 	clk_disable_unprepare(dev->pclk);
728 }
729 
730 static struct platform_driver atmel_i2s_driver = {
731 	.driver		= {
732 		.name	= "atmel_i2s",
733 		.of_match_table	= atmel_i2s_dt_ids,
734 	},
735 	.probe		= atmel_i2s_probe,
736 	.remove_new	= atmel_i2s_remove,
737 };
738 module_platform_driver(atmel_i2s_driver);
739 
740 MODULE_DESCRIPTION("Atmel I2S Controller driver");
741 MODULE_AUTHOR("Cyrille Pitchen <cyrille.pitchen@atmel.com>");
742 MODULE_LICENSE("GPL v2");
743