xref: /openbmc/linux/sound/soc/sunxi/sun4i-i2s.c (revision 0984d159)
1 /*
2  * Copyright (C) 2015 Andrea Venturi
3  * Andrea Venturi <be17068@iperbole.bo.it>
4  *
5  * Copyright (C) 2016 Maxime Ripard
6  * Maxime Ripard <maxime.ripard@free-electrons.com>
7  *
8  * This program is free software; you can redistribute it and/or
9  * modify it under the terms of the GNU General Public License as
10  * published by the Free Software Foundation; either version 2 of
11  * the License, or (at your option) any later version.
12  */
13 
14 #include <linux/clk.h>
15 #include <linux/dmaengine.h>
16 #include <linux/module.h>
17 #include <linux/platform_device.h>
18 #include <linux/pm_runtime.h>
19 #include <linux/regmap.h>
20 
21 #include <sound/dmaengine_pcm.h>
22 #include <sound/pcm_params.h>
23 #include <sound/soc.h>
24 #include <sound/soc-dai.h>
25 
26 #define SUN4I_I2S_CTRL_REG		0x00
27 #define SUN4I_I2S_CTRL_SDO_EN_MASK		GENMASK(11, 8)
28 #define SUN4I_I2S_CTRL_SDO_EN(sdo)			BIT(8 + (sdo))
29 #define SUN4I_I2S_CTRL_MODE_MASK		BIT(5)
30 #define SUN4I_I2S_CTRL_MODE_SLAVE			(1 << 5)
31 #define SUN4I_I2S_CTRL_MODE_MASTER			(0 << 5)
32 #define SUN4I_I2S_CTRL_TX_EN			BIT(2)
33 #define SUN4I_I2S_CTRL_RX_EN			BIT(1)
34 #define SUN4I_I2S_CTRL_GL_EN			BIT(0)
35 
36 #define SUN4I_I2S_FMT0_REG		0x04
37 #define SUN4I_I2S_FMT0_LRCLK_POLARITY_MASK	BIT(7)
38 #define SUN4I_I2S_FMT0_LRCLK_POLARITY_INVERTED		(1 << 7)
39 #define SUN4I_I2S_FMT0_LRCLK_POLARITY_NORMAL		(0 << 7)
40 #define SUN4I_I2S_FMT0_BCLK_POLARITY_MASK	BIT(6)
41 #define SUN4I_I2S_FMT0_BCLK_POLARITY_INVERTED		(1 << 6)
42 #define SUN4I_I2S_FMT0_BCLK_POLARITY_NORMAL		(0 << 6)
43 #define SUN4I_I2S_FMT0_SR_MASK			GENMASK(5, 4)
44 #define SUN4I_I2S_FMT0_SR(sr)				((sr) << 4)
45 #define SUN4I_I2S_FMT0_WSS_MASK			GENMASK(3, 2)
46 #define SUN4I_I2S_FMT0_WSS(wss)				((wss) << 2)
47 #define SUN4I_I2S_FMT0_FMT_MASK			GENMASK(1, 0)
48 #define SUN4I_I2S_FMT0_FMT_RIGHT_J			(2 << 0)
49 #define SUN4I_I2S_FMT0_FMT_LEFT_J			(1 << 0)
50 #define SUN4I_I2S_FMT0_FMT_I2S				(0 << 0)
51 
52 #define SUN4I_I2S_FMT1_REG		0x08
53 #define SUN4I_I2S_FIFO_TX_REG		0x0c
54 #define SUN4I_I2S_FIFO_RX_REG		0x10
55 
56 #define SUN4I_I2S_FIFO_CTRL_REG		0x14
57 #define SUN4I_I2S_FIFO_CTRL_FLUSH_TX		BIT(25)
58 #define SUN4I_I2S_FIFO_CTRL_FLUSH_RX		BIT(24)
59 #define SUN4I_I2S_FIFO_CTRL_TX_MODE_MASK	BIT(2)
60 #define SUN4I_I2S_FIFO_CTRL_TX_MODE(mode)		((mode) << 2)
61 #define SUN4I_I2S_FIFO_CTRL_RX_MODE_MASK	GENMASK(1, 0)
62 #define SUN4I_I2S_FIFO_CTRL_RX_MODE(mode)		(mode)
63 
64 #define SUN4I_I2S_FIFO_STA_REG		0x18
65 
66 #define SUN4I_I2S_DMA_INT_CTRL_REG	0x1c
67 #define SUN4I_I2S_DMA_INT_CTRL_TX_DRQ_EN	BIT(7)
68 #define SUN4I_I2S_DMA_INT_CTRL_RX_DRQ_EN	BIT(3)
69 
70 #define SUN4I_I2S_INT_STA_REG		0x20
71 
72 #define SUN4I_I2S_CLK_DIV_REG		0x24
73 #define SUN4I_I2S_CLK_DIV_MCLK_EN		BIT(7)
74 #define SUN4I_I2S_CLK_DIV_BCLK_MASK		GENMASK(6, 4)
75 #define SUN4I_I2S_CLK_DIV_BCLK(bclk)			((bclk) << 4)
76 #define SUN4I_I2S_CLK_DIV_MCLK_MASK		GENMASK(3, 0)
77 #define SUN4I_I2S_CLK_DIV_MCLK(mclk)			((mclk) << 0)
78 
79 #define SUN4I_I2S_RX_CNT_REG		0x28
80 #define SUN4I_I2S_TX_CNT_REG		0x2c
81 
82 #define SUN4I_I2S_TX_CHAN_SEL_REG	0x30
83 #define SUN4I_I2S_TX_CHAN_SEL(num_chan)		(((num_chan) - 1) << 0)
84 
85 #define SUN4I_I2S_TX_CHAN_MAP_REG	0x34
86 #define SUN4I_I2S_TX_CHAN_MAP(chan, sample)	((sample) << (chan << 2))
87 
88 #define SUN4I_I2S_RX_CHAN_SEL_REG	0x38
89 #define SUN4I_I2S_RX_CHAN_MAP_REG	0x3c
90 
91 struct sun4i_i2s {
92 	struct clk	*bus_clk;
93 	struct clk	*mod_clk;
94 	struct regmap	*regmap;
95 
96 	struct snd_dmaengine_dai_dma_data	playback_dma_data;
97 };
98 
99 struct sun4i_i2s_clk_div {
100 	u8	div;
101 	u8	val;
102 };
103 
104 static const struct sun4i_i2s_clk_div sun4i_i2s_bclk_div[] = {
105 	{ .div = 2, .val = 0 },
106 	{ .div = 4, .val = 1 },
107 	{ .div = 6, .val = 2 },
108 	{ .div = 8, .val = 3 },
109 	{ .div = 12, .val = 4 },
110 	{ .div = 16, .val = 5 },
111 };
112 
113 static const struct sun4i_i2s_clk_div sun4i_i2s_mclk_div[] = {
114 	{ .div = 1, .val = 0 },
115 	{ .div = 2, .val = 1 },
116 	{ .div = 4, .val = 2 },
117 	{ .div = 6, .val = 3 },
118 	{ .div = 8, .val = 4 },
119 	{ .div = 12, .val = 5 },
120 	{ .div = 16, .val = 6 },
121 	{ .div = 24, .val = 7 },
122 };
123 
124 static int sun4i_i2s_get_bclk_div(struct sun4i_i2s *i2s,
125 				  unsigned int oversample_rate,
126 				  unsigned int word_size)
127 {
128 	int div = oversample_rate / word_size / 2;
129 	int i;
130 
131 	for (i = 0; i < ARRAY_SIZE(sun4i_i2s_bclk_div); i++) {
132 		const struct sun4i_i2s_clk_div *bdiv = &sun4i_i2s_bclk_div[i];
133 
134 		if (bdiv->div == div)
135 			return bdiv->val;
136 	}
137 
138 	return -EINVAL;
139 }
140 
141 static int sun4i_i2s_get_mclk_div(struct sun4i_i2s *i2s,
142 				  unsigned int oversample_rate,
143 				  unsigned int module_rate,
144 				  unsigned int sampling_rate)
145 {
146 	int div = module_rate / sampling_rate / oversample_rate;
147 	int i;
148 
149 	for (i = 0; i < ARRAY_SIZE(sun4i_i2s_mclk_div); i++) {
150 		const struct sun4i_i2s_clk_div *mdiv = &sun4i_i2s_mclk_div[i];
151 
152 		if (mdiv->div == div)
153 			return mdiv->val;
154 	}
155 
156 	return -EINVAL;
157 }
158 
159 static int sun4i_i2s_oversample_rates[] = { 128, 192, 256, 384, 512, 768 };
160 
161 static int sun4i_i2s_set_clk_rate(struct sun4i_i2s *i2s,
162 				  unsigned int rate,
163 				  unsigned int word_size)
164 {
165 	unsigned int clk_rate;
166 	int bclk_div, mclk_div;
167 	int ret, i;
168 
169 	switch (rate) {
170 	case 176400:
171 	case 88200:
172 	case 44100:
173 	case 22050:
174 	case 11025:
175 		clk_rate = 22579200;
176 		break;
177 
178 	case 192000:
179 	case 128000:
180 	case 96000:
181 	case 64000:
182 	case 48000:
183 	case 32000:
184 	case 24000:
185 	case 16000:
186 	case 12000:
187 	case 8000:
188 		clk_rate = 24576000;
189 		break;
190 
191 	default:
192 		return -EINVAL;
193 	}
194 
195 	ret = clk_set_rate(i2s->mod_clk, clk_rate);
196 	if (ret)
197 		return ret;
198 
199 	/* Always favor the highest oversampling rate */
200 	for (i = (ARRAY_SIZE(sun4i_i2s_oversample_rates) - 1); i >= 0; i--) {
201 		unsigned int oversample_rate = sun4i_i2s_oversample_rates[i];
202 
203 		bclk_div = sun4i_i2s_get_bclk_div(i2s, oversample_rate,
204 						  word_size);
205 		mclk_div = sun4i_i2s_get_mclk_div(i2s, oversample_rate,
206 						  clk_rate,
207 						  rate);
208 
209 		if ((bclk_div >= 0) && (mclk_div >= 0))
210 			break;
211 	}
212 
213 	if ((bclk_div < 0) || (mclk_div < 0))
214 		return -EINVAL;
215 
216 	regmap_write(i2s->regmap, SUN4I_I2S_CLK_DIV_REG,
217 		     SUN4I_I2S_CLK_DIV_BCLK(bclk_div) |
218 		     SUN4I_I2S_CLK_DIV_MCLK(mclk_div) |
219 		     SUN4I_I2S_CLK_DIV_MCLK_EN);
220 
221 	return 0;
222 }
223 
224 static int sun4i_i2s_hw_params(struct snd_pcm_substream *substream,
225 			       struct snd_pcm_hw_params *params,
226 			       struct snd_soc_dai *dai)
227 {
228 	struct sun4i_i2s *i2s = snd_soc_dai_get_drvdata(dai);
229 	int sr, wss;
230 	u32 width;
231 
232 	if (params_channels(params) != 2)
233 		return -EINVAL;
234 
235 	switch (params_physical_width(params)) {
236 	case 16:
237 		width = DMA_SLAVE_BUSWIDTH_2_BYTES;
238 		break;
239 	default:
240 		return -EINVAL;
241 	}
242 	i2s->playback_dma_data.addr_width = width;
243 
244 	switch (params_width(params)) {
245 	case 16:
246 		sr = 0;
247 		wss = 0;
248 		break;
249 
250 	default:
251 		return -EINVAL;
252 	}
253 
254 	regmap_update_bits(i2s->regmap, SUN4I_I2S_FMT0_REG,
255 			   SUN4I_I2S_FMT0_WSS_MASK | SUN4I_I2S_FMT0_SR_MASK,
256 			   SUN4I_I2S_FMT0_WSS(wss) | SUN4I_I2S_FMT0_SR(sr));
257 
258 	return sun4i_i2s_set_clk_rate(i2s, params_rate(params),
259 				      params_width(params));
260 }
261 
262 static int sun4i_i2s_set_fmt(struct snd_soc_dai *dai, unsigned int fmt)
263 {
264 	struct sun4i_i2s *i2s = snd_soc_dai_get_drvdata(dai);
265 	u32 val;
266 
267 	/* DAI Mode */
268 	switch (fmt & SND_SOC_DAIFMT_FORMAT_MASK) {
269 	case SND_SOC_DAIFMT_I2S:
270 		val = SUN4I_I2S_FMT0_FMT_I2S;
271 		break;
272 	case SND_SOC_DAIFMT_LEFT_J:
273 		val = SUN4I_I2S_FMT0_FMT_LEFT_J;
274 		break;
275 	case SND_SOC_DAIFMT_RIGHT_J:
276 		val = SUN4I_I2S_FMT0_FMT_RIGHT_J;
277 		break;
278 	default:
279 		return -EINVAL;
280 	}
281 
282 	regmap_update_bits(i2s->regmap, SUN4I_I2S_FMT0_REG,
283 			   SUN4I_I2S_FMT0_FMT_MASK,
284 			   val);
285 
286 	/* DAI clock polarity */
287 	switch (fmt & SND_SOC_DAIFMT_INV_MASK) {
288 	case SND_SOC_DAIFMT_IB_IF:
289 		/* Invert both clocks */
290 		val = SUN4I_I2S_FMT0_BCLK_POLARITY_INVERTED |
291 			SUN4I_I2S_FMT0_LRCLK_POLARITY_INVERTED;
292 		break;
293 	case SND_SOC_DAIFMT_IB_NF:
294 		/* Invert bit clock */
295 		val = SUN4I_I2S_FMT0_BCLK_POLARITY_INVERTED |
296 			SUN4I_I2S_FMT0_LRCLK_POLARITY_NORMAL;
297 		break;
298 	case SND_SOC_DAIFMT_NB_IF:
299 		/* Invert frame clock */
300 		val = SUN4I_I2S_FMT0_LRCLK_POLARITY_INVERTED |
301 			SUN4I_I2S_FMT0_BCLK_POLARITY_NORMAL;
302 		break;
303 	case SND_SOC_DAIFMT_NB_NF:
304 		/* Nothing to do for both normal cases */
305 		val = SUN4I_I2S_FMT0_BCLK_POLARITY_NORMAL |
306 			SUN4I_I2S_FMT0_LRCLK_POLARITY_NORMAL;
307 		break;
308 	default:
309 		return -EINVAL;
310 	}
311 
312 	regmap_update_bits(i2s->regmap, SUN4I_I2S_FMT0_REG,
313 			   SUN4I_I2S_FMT0_BCLK_POLARITY_MASK |
314 			   SUN4I_I2S_FMT0_LRCLK_POLARITY_MASK,
315 			   val);
316 
317 	/* DAI clock master masks */
318 	switch (fmt & SND_SOC_DAIFMT_MASTER_MASK) {
319 	case SND_SOC_DAIFMT_CBS_CFS:
320 		/* BCLK and LRCLK master */
321 		val = SUN4I_I2S_CTRL_MODE_MASTER;
322 		break;
323 	case SND_SOC_DAIFMT_CBM_CFM:
324 		/* BCLK and LRCLK slave */
325 		val = SUN4I_I2S_CTRL_MODE_SLAVE;
326 		break;
327 	default:
328 		return -EINVAL;
329 	}
330 
331 	regmap_update_bits(i2s->regmap, SUN4I_I2S_CTRL_REG,
332 			   SUN4I_I2S_CTRL_MODE_MASK,
333 			   val);
334 
335 	/* Set significant bits in our FIFOs */
336 	regmap_update_bits(i2s->regmap, SUN4I_I2S_FIFO_CTRL_REG,
337 			   SUN4I_I2S_FIFO_CTRL_TX_MODE_MASK |
338 			   SUN4I_I2S_FIFO_CTRL_RX_MODE_MASK,
339 			   SUN4I_I2S_FIFO_CTRL_TX_MODE(1) |
340 			   SUN4I_I2S_FIFO_CTRL_RX_MODE(1));
341 	return 0;
342 }
343 
344 static void sun4i_i2s_start_playback(struct sun4i_i2s *i2s)
345 {
346 	/* Flush TX FIFO */
347 	regmap_update_bits(i2s->regmap, SUN4I_I2S_FIFO_CTRL_REG,
348 			   SUN4I_I2S_FIFO_CTRL_FLUSH_TX,
349 			   SUN4I_I2S_FIFO_CTRL_FLUSH_TX);
350 
351 	/* Clear TX counter */
352 	regmap_write(i2s->regmap, SUN4I_I2S_TX_CNT_REG, 0);
353 
354 	/* Enable TX Block */
355 	regmap_update_bits(i2s->regmap, SUN4I_I2S_CTRL_REG,
356 			   SUN4I_I2S_CTRL_TX_EN,
357 			   SUN4I_I2S_CTRL_TX_EN);
358 
359 	/* Enable TX DRQ */
360 	regmap_update_bits(i2s->regmap, SUN4I_I2S_DMA_INT_CTRL_REG,
361 			   SUN4I_I2S_DMA_INT_CTRL_TX_DRQ_EN,
362 			   SUN4I_I2S_DMA_INT_CTRL_TX_DRQ_EN);
363 }
364 
365 
366 static void sun4i_i2s_stop_playback(struct sun4i_i2s *i2s)
367 {
368 	/* Disable TX Block */
369 	regmap_update_bits(i2s->regmap, SUN4I_I2S_CTRL_REG,
370 			   SUN4I_I2S_CTRL_TX_EN,
371 			   0);
372 
373 	/* Disable TX DRQ */
374 	regmap_update_bits(i2s->regmap, SUN4I_I2S_DMA_INT_CTRL_REG,
375 			   SUN4I_I2S_DMA_INT_CTRL_TX_DRQ_EN,
376 			   0);
377 }
378 
379 static int sun4i_i2s_trigger(struct snd_pcm_substream *substream, int cmd,
380 			     struct snd_soc_dai *dai)
381 {
382 	struct sun4i_i2s *i2s = snd_soc_dai_get_drvdata(dai);
383 
384 	switch (cmd) {
385 	case SNDRV_PCM_TRIGGER_START:
386 	case SNDRV_PCM_TRIGGER_PAUSE_RELEASE:
387 	case SNDRV_PCM_TRIGGER_RESUME:
388 		if (substream->stream == SNDRV_PCM_STREAM_PLAYBACK)
389 			sun4i_i2s_start_playback(i2s);
390 		else
391 			return -EINVAL;
392 		break;
393 
394 	case SNDRV_PCM_TRIGGER_STOP:
395 	case SNDRV_PCM_TRIGGER_PAUSE_PUSH:
396 	case SNDRV_PCM_TRIGGER_SUSPEND:
397 		if (substream->stream == SNDRV_PCM_STREAM_PLAYBACK)
398 			sun4i_i2s_stop_playback(i2s);
399 		else
400 			return -EINVAL;
401 		break;
402 
403 	default:
404 		return -EINVAL;
405 	}
406 
407 	return 0;
408 }
409 
410 static int sun4i_i2s_startup(struct snd_pcm_substream *substream,
411 			     struct snd_soc_dai *dai)
412 {
413 	struct sun4i_i2s *i2s = snd_soc_dai_get_drvdata(dai);
414 
415 	/* Enable the whole hardware block */
416 	regmap_write(i2s->regmap, SUN4I_I2S_CTRL_REG,
417 		     SUN4I_I2S_CTRL_GL_EN);
418 
419 	/* Enable the first output line */
420 	regmap_update_bits(i2s->regmap, SUN4I_I2S_CTRL_REG,
421 			   SUN4I_I2S_CTRL_SDO_EN_MASK,
422 			   SUN4I_I2S_CTRL_SDO_EN(0));
423 
424 	/* Enable the first two channels */
425 	regmap_write(i2s->regmap, SUN4I_I2S_TX_CHAN_SEL_REG,
426 		     SUN4I_I2S_TX_CHAN_SEL(2));
427 
428 	/* Map them to the two first samples coming in */
429 	regmap_write(i2s->regmap, SUN4I_I2S_TX_CHAN_MAP_REG,
430 		     SUN4I_I2S_TX_CHAN_MAP(0, 0) | SUN4I_I2S_TX_CHAN_MAP(1, 1));
431 
432 	return clk_prepare_enable(i2s->mod_clk);
433 }
434 
435 static void sun4i_i2s_shutdown(struct snd_pcm_substream *substream,
436 			       struct snd_soc_dai *dai)
437 {
438 	struct sun4i_i2s *i2s = snd_soc_dai_get_drvdata(dai);
439 
440 	clk_disable_unprepare(i2s->mod_clk);
441 
442 	/* Disable our output lines */
443 	regmap_update_bits(i2s->regmap, SUN4I_I2S_CTRL_REG,
444 			   SUN4I_I2S_CTRL_SDO_EN_MASK, 0);
445 
446 	/* Disable the whole hardware block */
447 	regmap_write(i2s->regmap, SUN4I_I2S_CTRL_REG, 0);
448 }
449 
450 static const struct snd_soc_dai_ops sun4i_i2s_dai_ops = {
451 	.hw_params	= sun4i_i2s_hw_params,
452 	.set_fmt	= sun4i_i2s_set_fmt,
453 	.shutdown	= sun4i_i2s_shutdown,
454 	.startup	= sun4i_i2s_startup,
455 	.trigger	= sun4i_i2s_trigger,
456 };
457 
458 static int sun4i_i2s_dai_probe(struct snd_soc_dai *dai)
459 {
460 	struct sun4i_i2s *i2s = snd_soc_dai_get_drvdata(dai);
461 
462 	snd_soc_dai_init_dma_data(dai, &i2s->playback_dma_data, NULL);
463 
464 	snd_soc_dai_set_drvdata(dai, i2s);
465 
466 	return 0;
467 }
468 
469 static struct snd_soc_dai_driver sun4i_i2s_dai = {
470 	.probe = sun4i_i2s_dai_probe,
471 	.playback = {
472 		.stream_name = "Playback",
473 		.channels_min = 2,
474 		.channels_max = 2,
475 		.rates = SNDRV_PCM_RATE_8000_192000,
476 		.formats = SNDRV_PCM_FMTBIT_S16_LE,
477 	},
478 	.ops = &sun4i_i2s_dai_ops,
479 	.symmetric_rates = 1,
480 };
481 
482 static const struct snd_soc_component_driver sun4i_i2s_component = {
483 	.name	= "sun4i-dai",
484 };
485 
486 static bool sun4i_i2s_rd_reg(struct device *dev, unsigned int reg)
487 {
488 	switch (reg) {
489 	case SUN4I_I2S_FIFO_TX_REG:
490 		return false;
491 
492 	default:
493 		return true;
494 	}
495 }
496 
497 static bool sun4i_i2s_wr_reg(struct device *dev, unsigned int reg)
498 {
499 	switch (reg) {
500 	case SUN4I_I2S_FIFO_RX_REG:
501 	case SUN4I_I2S_FIFO_STA_REG:
502 		return false;
503 
504 	default:
505 		return true;
506 	}
507 }
508 
509 static bool sun4i_i2s_volatile_reg(struct device *dev, unsigned int reg)
510 {
511 	switch (reg) {
512 	case SUN4I_I2S_FIFO_RX_REG:
513 	case SUN4I_I2S_INT_STA_REG:
514 	case SUN4I_I2S_RX_CNT_REG:
515 	case SUN4I_I2S_TX_CNT_REG:
516 		return true;
517 
518 	default:
519 		return false;
520 	}
521 }
522 
523 static const struct reg_default sun4i_i2s_reg_defaults[] = {
524 	{ SUN4I_I2S_CTRL_REG, 0x00000000 },
525 	{ SUN4I_I2S_FMT0_REG, 0x0000000c },
526 	{ SUN4I_I2S_FMT1_REG, 0x00004020 },
527 	{ SUN4I_I2S_FIFO_CTRL_REG, 0x000400f0 },
528 	{ SUN4I_I2S_DMA_INT_CTRL_REG, 0x00000000 },
529 	{ SUN4I_I2S_CLK_DIV_REG, 0x00000000 },
530 	{ SUN4I_I2S_TX_CHAN_SEL_REG, 0x00000001 },
531 	{ SUN4I_I2S_TX_CHAN_MAP_REG, 0x76543210 },
532 	{ SUN4I_I2S_RX_CHAN_SEL_REG, 0x00000001 },
533 	{ SUN4I_I2S_RX_CHAN_MAP_REG, 0x00003210 },
534 };
535 
536 static const struct regmap_config sun4i_i2s_regmap_config = {
537 	.reg_bits	= 32,
538 	.reg_stride	= 4,
539 	.val_bits	= 32,
540 	.max_register	= SUN4I_I2S_RX_CHAN_MAP_REG,
541 
542 	.cache_type	= REGCACHE_FLAT,
543 	.reg_defaults	= sun4i_i2s_reg_defaults,
544 	.num_reg_defaults	= ARRAY_SIZE(sun4i_i2s_reg_defaults),
545 	.writeable_reg	= sun4i_i2s_wr_reg,
546 	.readable_reg	= sun4i_i2s_rd_reg,
547 	.volatile_reg	= sun4i_i2s_volatile_reg,
548 };
549 
550 static int sun4i_i2s_runtime_resume(struct device *dev)
551 {
552 	struct sun4i_i2s *i2s = dev_get_drvdata(dev);
553 	int ret;
554 
555 	ret = clk_prepare_enable(i2s->bus_clk);
556 	if (ret) {
557 		dev_err(dev, "Failed to enable bus clock\n");
558 		return ret;
559 	}
560 
561 	regcache_cache_only(i2s->regmap, false);
562 	regcache_mark_dirty(i2s->regmap);
563 
564 	ret = regcache_sync(i2s->regmap);
565 	if (ret) {
566 		dev_err(dev, "Failed to sync regmap cache\n");
567 		goto err_disable_clk;
568 	}
569 
570 	return 0;
571 
572 err_disable_clk:
573 	clk_disable_unprepare(i2s->bus_clk);
574 	return ret;
575 }
576 
577 static int sun4i_i2s_runtime_suspend(struct device *dev)
578 {
579 	struct sun4i_i2s *i2s = dev_get_drvdata(dev);
580 
581 	regcache_cache_only(i2s->regmap, true);
582 
583 	clk_disable_unprepare(i2s->bus_clk);
584 
585 	return 0;
586 }
587 
588 static int sun4i_i2s_probe(struct platform_device *pdev)
589 {
590 	struct sun4i_i2s *i2s;
591 	struct resource *res;
592 	void __iomem *regs;
593 	int irq, ret;
594 
595 	i2s = devm_kzalloc(&pdev->dev, sizeof(*i2s), GFP_KERNEL);
596 	if (!i2s)
597 		return -ENOMEM;
598 	platform_set_drvdata(pdev, i2s);
599 
600 	res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
601 	regs = devm_ioremap_resource(&pdev->dev, res);
602 	if (IS_ERR(regs))
603 		return PTR_ERR(regs);
604 
605 	irq = platform_get_irq(pdev, 0);
606 	if (irq < 0) {
607 		dev_err(&pdev->dev, "Can't retrieve our interrupt\n");
608 		return irq;
609 	}
610 
611 	i2s->bus_clk = devm_clk_get(&pdev->dev, "apb");
612 	if (IS_ERR(i2s->bus_clk)) {
613 		dev_err(&pdev->dev, "Can't get our bus clock\n");
614 		return PTR_ERR(i2s->bus_clk);
615 	}
616 
617 	i2s->regmap = devm_regmap_init_mmio(&pdev->dev, regs,
618 					    &sun4i_i2s_regmap_config);
619 	if (IS_ERR(i2s->regmap)) {
620 		dev_err(&pdev->dev, "Regmap initialisation failed\n");
621 		return PTR_ERR(i2s->regmap);
622 	}
623 
624 	i2s->mod_clk = devm_clk_get(&pdev->dev, "mod");
625 	if (IS_ERR(i2s->mod_clk)) {
626 		dev_err(&pdev->dev, "Can't get our mod clock\n");
627 		return PTR_ERR(i2s->mod_clk);
628 	}
629 
630 	i2s->playback_dma_data.addr = res->start + SUN4I_I2S_FIFO_TX_REG;
631 	i2s->playback_dma_data.maxburst = 4;
632 
633 	pm_runtime_enable(&pdev->dev);
634 	if (!pm_runtime_enabled(&pdev->dev)) {
635 		ret = sun4i_i2s_runtime_resume(&pdev->dev);
636 		if (ret)
637 			goto err_pm_disable;
638 	}
639 
640 	ret = devm_snd_soc_register_component(&pdev->dev,
641 					      &sun4i_i2s_component,
642 					      &sun4i_i2s_dai, 1);
643 	if (ret) {
644 		dev_err(&pdev->dev, "Could not register DAI\n");
645 		goto err_suspend;
646 	}
647 
648 	ret = snd_dmaengine_pcm_register(&pdev->dev, NULL, 0);
649 	if (ret) {
650 		dev_err(&pdev->dev, "Could not register PCM\n");
651 		goto err_suspend;
652 	}
653 
654 	return 0;
655 
656 err_suspend:
657 	if (!pm_runtime_status_suspended(&pdev->dev))
658 		sun4i_i2s_runtime_suspend(&pdev->dev);
659 err_pm_disable:
660 	pm_runtime_disable(&pdev->dev);
661 
662 	return ret;
663 }
664 
665 static int sun4i_i2s_remove(struct platform_device *pdev)
666 {
667 	snd_dmaengine_pcm_unregister(&pdev->dev);
668 
669 	pm_runtime_disable(&pdev->dev);
670 	if (!pm_runtime_status_suspended(&pdev->dev))
671 		sun4i_i2s_runtime_suspend(&pdev->dev);
672 
673 	return 0;
674 }
675 
676 static const struct of_device_id sun4i_i2s_match[] = {
677 	{ .compatible = "allwinner,sun4i-a10-i2s", },
678 	{}
679 };
680 MODULE_DEVICE_TABLE(of, sun4i_i2s_match);
681 
682 static const struct dev_pm_ops sun4i_i2s_pm_ops = {
683 	.runtime_resume		= sun4i_i2s_runtime_resume,
684 	.runtime_suspend	= sun4i_i2s_runtime_suspend,
685 };
686 
687 static struct platform_driver sun4i_i2s_driver = {
688 	.probe	= sun4i_i2s_probe,
689 	.remove	= sun4i_i2s_remove,
690 	.driver	= {
691 		.name		= "sun4i-i2s",
692 		.of_match_table	= sun4i_i2s_match,
693 		.pm		= &sun4i_i2s_pm_ops,
694 	},
695 };
696 module_platform_driver(sun4i_i2s_driver);
697 
698 MODULE_AUTHOR("Andrea Venturi <be17068@iperbole.bo.it>");
699 MODULE_AUTHOR("Maxime Ripard <maxime.ripard@free-electrons.com>");
700 MODULE_DESCRIPTION("Allwinner A10 I2S driver");
701 MODULE_LICENSE("GPL");
702