xref: /linux/sound/soc/xtensa/xtfpga-i2s.c (revision 18f90d372cf35b387663f1567de701e5393f6eb5)
1 /*
2  * Xtfpga I2S controller driver
3  *
4  * Copyright (c) 2014 Cadence Design Systems Inc.
5  *
6  * This program is free software; you can redistribute it and/or modify
7  * it under the terms of the GNU General Public License version 2 as
8  * published by the Free Software Foundation.
9  */
10 
11 #include <linux/clk.h>
12 #include <linux/io.h>
13 #include <linux/module.h>
14 #include <linux/of.h>
15 #include <linux/platform_device.h>
16 #include <linux/pm_runtime.h>
17 #include <sound/pcm_params.h>
18 #include <sound/soc.h>
19 
20 #define DRV_NAME	"xtfpga-i2s"
21 
22 #define XTFPGA_I2S_VERSION	0x00
23 #define XTFPGA_I2S_CONFIG	0x04
24 #define XTFPGA_I2S_INT_MASK	0x08
25 #define XTFPGA_I2S_INT_STATUS	0x0c
26 #define XTFPGA_I2S_CHAN0_DATA	0x10
27 #define XTFPGA_I2S_CHAN1_DATA	0x14
28 #define XTFPGA_I2S_CHAN2_DATA	0x18
29 #define XTFPGA_I2S_CHAN3_DATA	0x1c
30 
31 #define XTFPGA_I2S_CONFIG_TX_ENABLE	0x1
32 #define XTFPGA_I2S_CONFIG_INT_ENABLE	0x2
33 #define XTFPGA_I2S_CONFIG_LEFT		0x4
34 #define XTFPGA_I2S_CONFIG_RATIO_BASE	8
35 #define XTFPGA_I2S_CONFIG_RATIO_MASK	0x0000ff00
36 #define XTFPGA_I2S_CONFIG_RES_BASE	16
37 #define XTFPGA_I2S_CONFIG_RES_MASK	0x003f0000
38 #define XTFPGA_I2S_CONFIG_LEVEL_BASE	24
39 #define XTFPGA_I2S_CONFIG_LEVEL_MASK	0x0f000000
40 #define XTFPGA_I2S_CONFIG_CHANNEL_BASE	28
41 
42 #define XTFPGA_I2S_INT_UNDERRUN		0x1
43 #define XTFPGA_I2S_INT_LEVEL		0x2
44 #define XTFPGA_I2S_INT_VALID		0x3
45 
46 #define XTFPGA_I2S_FIFO_SIZE		8192
47 
48 /*
49  * I2S controller operation:
50  *
51  * Enabling TX: output 1 period of zeros (starting with left channel)
52  * and then queued data.
53  *
54  * Level status and interrupt: whenever FIFO level is below FIFO trigger,
55  * level status is 1 and an IRQ is asserted (if enabled).
56  *
57  * Underrun status and interrupt: whenever FIFO is empty, underrun status
58  * is 1 and an IRQ is asserted (if enabled).
59  */
60 struct xtfpga_i2s {
61 	struct device *dev;
62 	struct clk *clk;
63 	struct regmap *regmap;
64 	void __iomem *regs;
65 
66 	/* current playback substream. NULL if not playing.
67 	 *
68 	 * Access to that field is synchronized between the interrupt handler
69 	 * and userspace through RCU.
70 	 *
71 	 * Interrupt handler (threaded part) does PIO on substream data in RCU
72 	 * read-side critical section. Trigger callback sets and clears the
73 	 * pointer when the playback is started and stopped with
74 	 * rcu_assign_pointer. When userspace is about to free the playback
75 	 * stream in the pcm_close callback it synchronizes with the interrupt
76 	 * handler by means of synchronize_rcu call.
77 	 */
78 	struct snd_pcm_substream __rcu *tx_substream;
79 	unsigned (*tx_fn)(struct xtfpga_i2s *i2s,
80 			  struct snd_pcm_runtime *runtime,
81 			  unsigned tx_ptr);
82 	unsigned tx_ptr; /* next frame index in the sample buffer */
83 
84 	/* current fifo level estimate.
85 	 * Doesn't have to be perfectly accurate, but must be not less than
86 	 * the actual FIFO level in order to avoid stall on push attempt.
87 	 */
88 	unsigned tx_fifo_level;
89 
90 	/* FIFO level at which level interrupt occurs */
91 	unsigned tx_fifo_low;
92 
93 	/* maximal FIFO level */
94 	unsigned tx_fifo_high;
95 };
96 
97 static bool xtfpga_i2s_wr_reg(struct device *dev, unsigned int reg)
98 {
99 	return reg >= XTFPGA_I2S_CONFIG;
100 }
101 
102 static bool xtfpga_i2s_rd_reg(struct device *dev, unsigned int reg)
103 {
104 	return reg < XTFPGA_I2S_CHAN0_DATA;
105 }
106 
107 static bool xtfpga_i2s_volatile_reg(struct device *dev, unsigned int reg)
108 {
109 	return reg == XTFPGA_I2S_INT_STATUS;
110 }
111 
112 static const struct regmap_config xtfpga_i2s_regmap_config = {
113 	.reg_bits = 32,
114 	.reg_stride = 4,
115 	.val_bits = 32,
116 	.max_register = XTFPGA_I2S_CHAN3_DATA,
117 	.writeable_reg = xtfpga_i2s_wr_reg,
118 	.readable_reg = xtfpga_i2s_rd_reg,
119 	.volatile_reg = xtfpga_i2s_volatile_reg,
120 	.cache_type = REGCACHE_FLAT,
121 };
122 
123 /* Generate functions that do PIO from TX DMA area to FIFO for all supported
124  * stream formats.
125  * Functions will be called xtfpga_pcm_tx_<channels>x<sample bits>, e.g.
126  * xtfpga_pcm_tx_2x16 for 16-bit stereo.
127  *
128  * FIFO consists of 32-bit words, one word per channel, always 2 channels.
129  * If I2S interface is configured with smaller sample resolution, only
130  * the LSB of each word is used.
131  */
132 #define xtfpga_pcm_tx_fn(channels, sample_bits) \
133 static unsigned xtfpga_pcm_tx_##channels##x##sample_bits( \
134 	struct xtfpga_i2s *i2s, struct snd_pcm_runtime *runtime, \
135 	unsigned tx_ptr) \
136 { \
137 	const u##sample_bits (*p)[channels] = \
138 		(void *)runtime->dma_area; \
139 \
140 	for (; i2s->tx_fifo_level < i2s->tx_fifo_high; \
141 	     i2s->tx_fifo_level += 2) { \
142 		iowrite32(p[tx_ptr][0], \
143 			  i2s->regs + XTFPGA_I2S_CHAN0_DATA); \
144 		iowrite32(p[tx_ptr][channels - 1], \
145 			  i2s->regs + XTFPGA_I2S_CHAN0_DATA); \
146 		if (++tx_ptr >= runtime->buffer_size) \
147 			tx_ptr = 0; \
148 	} \
149 	return tx_ptr; \
150 }
151 
152 xtfpga_pcm_tx_fn(1, 16)
153 xtfpga_pcm_tx_fn(2, 16)
154 xtfpga_pcm_tx_fn(1, 32)
155 xtfpga_pcm_tx_fn(2, 32)
156 
157 #undef xtfpga_pcm_tx_fn
158 
159 static bool xtfpga_pcm_push_tx(struct xtfpga_i2s *i2s)
160 {
161 	struct snd_pcm_substream *tx_substream;
162 	bool tx_active;
163 
164 	rcu_read_lock();
165 	tx_substream = rcu_dereference(i2s->tx_substream);
166 	tx_active = tx_substream && snd_pcm_running(tx_substream);
167 	if (tx_active) {
168 		unsigned tx_ptr = READ_ONCE(i2s->tx_ptr);
169 		unsigned new_tx_ptr = i2s->tx_fn(i2s, tx_substream->runtime,
170 						 tx_ptr);
171 
172 		cmpxchg(&i2s->tx_ptr, tx_ptr, new_tx_ptr);
173 	}
174 	rcu_read_unlock();
175 
176 	return tx_active;
177 }
178 
179 static void xtfpga_pcm_refill_fifo(struct xtfpga_i2s *i2s)
180 {
181 	unsigned int_status;
182 	unsigned i;
183 
184 	regmap_read(i2s->regmap, XTFPGA_I2S_INT_STATUS,
185 		    &int_status);
186 
187 	for (i = 0; i < 2; ++i) {
188 		bool tx_active = xtfpga_pcm_push_tx(i2s);
189 
190 		regmap_write(i2s->regmap, XTFPGA_I2S_INT_STATUS,
191 			     XTFPGA_I2S_INT_VALID);
192 		if (tx_active)
193 			regmap_read(i2s->regmap, XTFPGA_I2S_INT_STATUS,
194 				    &int_status);
195 
196 		if (!tx_active ||
197 		    !(int_status & XTFPGA_I2S_INT_LEVEL))
198 			break;
199 
200 		/* After the push the level IRQ is still asserted,
201 		 * means FIFO level is below tx_fifo_low. Estimate
202 		 * it as tx_fifo_low.
203 		 */
204 		i2s->tx_fifo_level = i2s->tx_fifo_low;
205 	}
206 
207 	if (!(int_status & XTFPGA_I2S_INT_LEVEL))
208 		regmap_write(i2s->regmap, XTFPGA_I2S_INT_MASK,
209 			     XTFPGA_I2S_INT_VALID);
210 	else if (!(int_status & XTFPGA_I2S_INT_UNDERRUN))
211 		regmap_write(i2s->regmap, XTFPGA_I2S_INT_MASK,
212 			     XTFPGA_I2S_INT_UNDERRUN);
213 
214 	if (!(int_status & XTFPGA_I2S_INT_UNDERRUN))
215 		regmap_update_bits(i2s->regmap, XTFPGA_I2S_CONFIG,
216 				   XTFPGA_I2S_CONFIG_INT_ENABLE |
217 				   XTFPGA_I2S_CONFIG_TX_ENABLE,
218 				   XTFPGA_I2S_CONFIG_INT_ENABLE |
219 				   XTFPGA_I2S_CONFIG_TX_ENABLE);
220 	else
221 		regmap_update_bits(i2s->regmap, XTFPGA_I2S_CONFIG,
222 				   XTFPGA_I2S_CONFIG_INT_ENABLE |
223 				   XTFPGA_I2S_CONFIG_TX_ENABLE, 0);
224 }
225 
226 static irqreturn_t xtfpga_i2s_threaded_irq_handler(int irq, void *dev_id)
227 {
228 	struct xtfpga_i2s *i2s = dev_id;
229 	struct snd_pcm_substream *tx_substream;
230 	unsigned config, int_status, int_mask;
231 
232 	regmap_read(i2s->regmap, XTFPGA_I2S_CONFIG, &config);
233 	regmap_read(i2s->regmap, XTFPGA_I2S_INT_MASK, &int_mask);
234 	regmap_read(i2s->regmap, XTFPGA_I2S_INT_STATUS, &int_status);
235 
236 	if (!(config & XTFPGA_I2S_CONFIG_INT_ENABLE) ||
237 	    !(int_status & int_mask & XTFPGA_I2S_INT_VALID))
238 		return IRQ_NONE;
239 
240 	/* Update FIFO level estimate in accordance with interrupt status
241 	 * register.
242 	 */
243 	if (int_status & XTFPGA_I2S_INT_UNDERRUN) {
244 		i2s->tx_fifo_level = 0;
245 		regmap_update_bits(i2s->regmap, XTFPGA_I2S_CONFIG,
246 				   XTFPGA_I2S_CONFIG_TX_ENABLE, 0);
247 	} else {
248 		/* The FIFO isn't empty, but is below tx_fifo_low. Estimate
249 		 * it as tx_fifo_low.
250 		 */
251 		i2s->tx_fifo_level = i2s->tx_fifo_low;
252 	}
253 
254 	rcu_read_lock();
255 	tx_substream = rcu_dereference(i2s->tx_substream);
256 
257 	if (tx_substream && snd_pcm_running(tx_substream)) {
258 		snd_pcm_period_elapsed(tx_substream);
259 		if (int_status & XTFPGA_I2S_INT_UNDERRUN)
260 			dev_dbg_ratelimited(i2s->dev, "%s: underrun\n",
261 					    __func__);
262 	}
263 	rcu_read_unlock();
264 
265 	/* Refill FIFO, update allowed IRQ reasons, enable IRQ if FIFO is
266 	 * not empty.
267 	 */
268 	xtfpga_pcm_refill_fifo(i2s);
269 
270 	return IRQ_HANDLED;
271 }
272 
273 static int xtfpga_i2s_startup(struct snd_pcm_substream *substream,
274 			      struct snd_soc_dai *dai)
275 {
276 	struct xtfpga_i2s *i2s = snd_soc_dai_get_drvdata(dai);
277 
278 	snd_soc_dai_set_dma_data(dai, substream, i2s);
279 	return 0;
280 }
281 
282 static int xtfpga_i2s_hw_params(struct snd_pcm_substream *substream,
283 				struct snd_pcm_hw_params *params,
284 				struct snd_soc_dai *dai)
285 {
286 	struct xtfpga_i2s *i2s = snd_soc_dai_get_drvdata(dai);
287 	unsigned srate = params_rate(params);
288 	unsigned channels = params_channels(params);
289 	unsigned period_size = params_period_size(params);
290 	unsigned sample_size = snd_pcm_format_width(params_format(params));
291 	unsigned freq, ratio, level;
292 	int err;
293 
294 	regmap_update_bits(i2s->regmap, XTFPGA_I2S_CONFIG,
295 			   XTFPGA_I2S_CONFIG_RES_MASK,
296 			   sample_size << XTFPGA_I2S_CONFIG_RES_BASE);
297 
298 	freq = 256 * srate;
299 	err = clk_set_rate(i2s->clk, freq);
300 	if (err < 0)
301 		return err;
302 
303 	/* ratio field of the config register controls MCLK->I2S clock
304 	 * derivation: I2S clock = MCLK / (2 * (ratio + 2)).
305 	 *
306 	 * So with MCLK = 256 * sample rate ratio is 0 for 32 bit stereo
307 	 * and 2 for 16 bit stereo.
308 	 */
309 	ratio = (freq - (srate * sample_size * 8)) /
310 		(srate * sample_size * 4);
311 
312 	regmap_update_bits(i2s->regmap, XTFPGA_I2S_CONFIG,
313 			   XTFPGA_I2S_CONFIG_RATIO_MASK,
314 			   ratio << XTFPGA_I2S_CONFIG_RATIO_BASE);
315 
316 	i2s->tx_fifo_low = XTFPGA_I2S_FIFO_SIZE / 2;
317 
318 	/* period_size * 2: FIFO always gets 2 samples per frame */
319 	for (level = 1;
320 	     i2s->tx_fifo_low / 2 >= period_size * 2 &&
321 	     level < (XTFPGA_I2S_CONFIG_LEVEL_MASK >>
322 		      XTFPGA_I2S_CONFIG_LEVEL_BASE); ++level)
323 		i2s->tx_fifo_low /= 2;
324 
325 	i2s->tx_fifo_high = 2 * i2s->tx_fifo_low;
326 
327 	regmap_update_bits(i2s->regmap, XTFPGA_I2S_CONFIG,
328 			   XTFPGA_I2S_CONFIG_LEVEL_MASK,
329 			   level << XTFPGA_I2S_CONFIG_LEVEL_BASE);
330 
331 	dev_dbg(i2s->dev,
332 		"%s srate: %u, channels: %u, sample_size: %u, period_size: %u\n",
333 		__func__, srate, channels, sample_size, period_size);
334 	dev_dbg(i2s->dev, "%s freq: %u, ratio: %u, level: %u\n",
335 		__func__, freq, ratio, level);
336 
337 	return 0;
338 }
339 
340 static int xtfpga_i2s_set_fmt(struct snd_soc_dai *cpu_dai,
341 			      unsigned int fmt)
342 {
343 	if ((fmt & SND_SOC_DAIFMT_INV_MASK) != SND_SOC_DAIFMT_NB_NF)
344 		return -EINVAL;
345 	if ((fmt & SND_SOC_DAIFMT_MASTER_MASK) != SND_SOC_DAIFMT_CBS_CFS)
346 		return -EINVAL;
347 	if ((fmt & SND_SOC_DAIFMT_FORMAT_MASK) != SND_SOC_DAIFMT_I2S)
348 		return -EINVAL;
349 
350 	return 0;
351 }
352 
353 /* PCM */
354 
355 static const struct snd_pcm_hardware xtfpga_pcm_hardware = {
356 	.info = SNDRV_PCM_INFO_INTERLEAVED |
357 		SNDRV_PCM_INFO_MMAP_VALID |
358 		SNDRV_PCM_INFO_BLOCK_TRANSFER,
359 	.formats		= SNDRV_PCM_FMTBIT_S16_LE |
360 				  SNDRV_PCM_FMTBIT_S32_LE,
361 	.channels_min		= 1,
362 	.channels_max		= 2,
363 	.period_bytes_min	= 2,
364 	.period_bytes_max	= XTFPGA_I2S_FIFO_SIZE / 2 * 8,
365 	.periods_min		= 2,
366 	.periods_max		= XTFPGA_I2S_FIFO_SIZE * 8 / 2,
367 	.buffer_bytes_max	= XTFPGA_I2S_FIFO_SIZE * 8,
368 	.fifo_size		= 16,
369 };
370 
371 static int xtfpga_pcm_open(struct snd_pcm_substream *substream)
372 {
373 	struct snd_pcm_runtime *runtime = substream->runtime;
374 	struct snd_soc_pcm_runtime *rtd = substream->private_data;
375 	void *p;
376 
377 	snd_soc_set_runtime_hwparams(substream, &xtfpga_pcm_hardware);
378 	p = snd_soc_dai_get_dma_data(rtd->cpu_dai, substream);
379 	runtime->private_data = p;
380 
381 	return 0;
382 }
383 
384 static int xtfpga_pcm_close(struct snd_pcm_substream *substream)
385 {
386 	synchronize_rcu();
387 	return 0;
388 }
389 
390 static int xtfpga_pcm_hw_params(struct snd_pcm_substream *substream,
391 				struct snd_pcm_hw_params *hw_params)
392 {
393 	int ret;
394 	struct snd_pcm_runtime *runtime = substream->runtime;
395 	struct xtfpga_i2s *i2s = runtime->private_data;
396 	unsigned channels = params_channels(hw_params);
397 
398 	switch (channels) {
399 	case 1:
400 	case 2:
401 		break;
402 
403 	default:
404 		return -EINVAL;
405 
406 	}
407 
408 	switch (params_format(hw_params)) {
409 	case SNDRV_PCM_FORMAT_S16_LE:
410 		i2s->tx_fn = (channels == 1) ?
411 			xtfpga_pcm_tx_1x16 :
412 			xtfpga_pcm_tx_2x16;
413 		break;
414 
415 	case SNDRV_PCM_FORMAT_S32_LE:
416 		i2s->tx_fn = (channels == 1) ?
417 			xtfpga_pcm_tx_1x32 :
418 			xtfpga_pcm_tx_2x32;
419 		break;
420 
421 	default:
422 		return -EINVAL;
423 	}
424 
425 	ret = snd_pcm_lib_malloc_pages(substream,
426 				       params_buffer_bytes(hw_params));
427 	return ret;
428 }
429 
430 static int xtfpga_pcm_trigger(struct snd_pcm_substream *substream, int cmd)
431 {
432 	int ret = 0;
433 	struct snd_pcm_runtime *runtime = substream->runtime;
434 	struct xtfpga_i2s *i2s = runtime->private_data;
435 
436 	switch (cmd) {
437 	case SNDRV_PCM_TRIGGER_START:
438 	case SNDRV_PCM_TRIGGER_RESUME:
439 	case SNDRV_PCM_TRIGGER_PAUSE_RELEASE:
440 		WRITE_ONCE(i2s->tx_ptr, 0);
441 		rcu_assign_pointer(i2s->tx_substream, substream);
442 		xtfpga_pcm_refill_fifo(i2s);
443 		break;
444 
445 	case SNDRV_PCM_TRIGGER_STOP:
446 	case SNDRV_PCM_TRIGGER_SUSPEND:
447 	case SNDRV_PCM_TRIGGER_PAUSE_PUSH:
448 		rcu_assign_pointer(i2s->tx_substream, NULL);
449 		break;
450 
451 	default:
452 		ret = -EINVAL;
453 		break;
454 	}
455 	return ret;
456 }
457 
458 static snd_pcm_uframes_t xtfpga_pcm_pointer(struct snd_pcm_substream *substream)
459 {
460 	struct snd_pcm_runtime *runtime = substream->runtime;
461 	struct xtfpga_i2s *i2s = runtime->private_data;
462 	snd_pcm_uframes_t pos = READ_ONCE(i2s->tx_ptr);
463 
464 	return pos < runtime->buffer_size ? pos : 0;
465 }
466 
467 static int xtfpga_pcm_new(struct snd_soc_pcm_runtime *rtd)
468 {
469 	struct snd_card *card = rtd->card->snd_card;
470 	size_t size = xtfpga_pcm_hardware.buffer_bytes_max;
471 
472 	snd_pcm_lib_preallocate_pages_for_all(rtd->pcm, SNDRV_DMA_TYPE_DEV,
473 					      card->dev, size, size);
474 	return 0;
475 }
476 
477 static const struct snd_pcm_ops xtfpga_pcm_ops = {
478 	.open		= xtfpga_pcm_open,
479 	.close		= xtfpga_pcm_close,
480 	.ioctl		= snd_pcm_lib_ioctl,
481 	.hw_params	= xtfpga_pcm_hw_params,
482 	.trigger	= xtfpga_pcm_trigger,
483 	.pointer	= xtfpga_pcm_pointer,
484 };
485 
486 static const struct snd_soc_component_driver xtfpga_i2s_component = {
487 	.name		= DRV_NAME,
488 	.pcm_new	= xtfpga_pcm_new,
489 	.ops		= &xtfpga_pcm_ops,
490 };
491 
492 static const struct snd_soc_dai_ops xtfpga_i2s_dai_ops = {
493 	.startup	= xtfpga_i2s_startup,
494 	.hw_params      = xtfpga_i2s_hw_params,
495 	.set_fmt        = xtfpga_i2s_set_fmt,
496 };
497 
498 static struct snd_soc_dai_driver xtfpga_i2s_dai[] = {
499 	{
500 		.name = "xtfpga-i2s",
501 		.id = 0,
502 		.playback = {
503 			.channels_min = 1,
504 			.channels_max = 2,
505 			.rates = SNDRV_PCM_RATE_8000_96000,
506 			.formats = SNDRV_PCM_FMTBIT_S16_LE |
507 				   SNDRV_PCM_FMTBIT_S32_LE,
508 		},
509 		.ops = &xtfpga_i2s_dai_ops,
510 	},
511 };
512 
513 static int xtfpga_i2s_runtime_suspend(struct device *dev)
514 {
515 	struct xtfpga_i2s *i2s = dev_get_drvdata(dev);
516 
517 	clk_disable_unprepare(i2s->clk);
518 	return 0;
519 }
520 
521 static int xtfpga_i2s_runtime_resume(struct device *dev)
522 {
523 	struct xtfpga_i2s *i2s = dev_get_drvdata(dev);
524 	int ret;
525 
526 	ret = clk_prepare_enable(i2s->clk);
527 	if (ret) {
528 		dev_err(dev, "clk_prepare_enable failed: %d\n", ret);
529 		return ret;
530 	}
531 	return 0;
532 }
533 
534 static int xtfpga_i2s_probe(struct platform_device *pdev)
535 {
536 	struct xtfpga_i2s *i2s;
537 	struct resource *mem;
538 	int err, irq;
539 
540 	i2s = devm_kzalloc(&pdev->dev, sizeof(*i2s), GFP_KERNEL);
541 	if (!i2s) {
542 		err = -ENOMEM;
543 		goto err;
544 	}
545 	platform_set_drvdata(pdev, i2s);
546 	i2s->dev = &pdev->dev;
547 	dev_dbg(&pdev->dev, "dev: %p, i2s: %p\n", &pdev->dev, i2s);
548 
549 	mem = platform_get_resource(pdev, IORESOURCE_MEM, 0);
550 	i2s->regs = devm_ioremap_resource(&pdev->dev, mem);
551 	if (IS_ERR(i2s->regs)) {
552 		err = PTR_ERR(i2s->regs);
553 		goto err;
554 	}
555 
556 	i2s->regmap = devm_regmap_init_mmio(&pdev->dev, i2s->regs,
557 					    &xtfpga_i2s_regmap_config);
558 	if (IS_ERR(i2s->regmap)) {
559 		dev_err(&pdev->dev, "regmap init failed\n");
560 		err = PTR_ERR(i2s->regmap);
561 		goto err;
562 	}
563 
564 	i2s->clk = devm_clk_get(&pdev->dev, NULL);
565 	if (IS_ERR(i2s->clk)) {
566 		dev_err(&pdev->dev, "couldn't get clock\n");
567 		err = PTR_ERR(i2s->clk);
568 		goto err;
569 	}
570 
571 	regmap_write(i2s->regmap, XTFPGA_I2S_CONFIG,
572 		     (0x1 << XTFPGA_I2S_CONFIG_CHANNEL_BASE));
573 	regmap_write(i2s->regmap, XTFPGA_I2S_INT_STATUS, XTFPGA_I2S_INT_VALID);
574 	regmap_write(i2s->regmap, XTFPGA_I2S_INT_MASK, XTFPGA_I2S_INT_UNDERRUN);
575 
576 	irq = platform_get_irq(pdev, 0);
577 	if (irq < 0) {
578 		dev_err(&pdev->dev, "No IRQ resource\n");
579 		err = irq;
580 		goto err;
581 	}
582 	err = devm_request_threaded_irq(&pdev->dev, irq, NULL,
583 					xtfpga_i2s_threaded_irq_handler,
584 					IRQF_SHARED | IRQF_ONESHOT,
585 					pdev->name, i2s);
586 	if (err < 0) {
587 		dev_err(&pdev->dev, "request_irq failed\n");
588 		goto err;
589 	}
590 
591 	err = devm_snd_soc_register_component(&pdev->dev,
592 					      &xtfpga_i2s_component,
593 					      xtfpga_i2s_dai,
594 					      ARRAY_SIZE(xtfpga_i2s_dai));
595 	if (err < 0) {
596 		dev_err(&pdev->dev, "couldn't register component\n");
597 		goto err;
598 	}
599 
600 	pm_runtime_enable(&pdev->dev);
601 	if (!pm_runtime_enabled(&pdev->dev)) {
602 		err = xtfpga_i2s_runtime_resume(&pdev->dev);
603 		if (err)
604 			goto err_pm_disable;
605 	}
606 	return 0;
607 
608 err_pm_disable:
609 	pm_runtime_disable(&pdev->dev);
610 err:
611 	dev_err(&pdev->dev, "%s: err = %d\n", __func__, err);
612 	return err;
613 }
614 
615 static int xtfpga_i2s_remove(struct platform_device *pdev)
616 {
617 	struct xtfpga_i2s *i2s = dev_get_drvdata(&pdev->dev);
618 
619 	if (i2s->regmap && !IS_ERR(i2s->regmap)) {
620 		regmap_write(i2s->regmap, XTFPGA_I2S_CONFIG, 0);
621 		regmap_write(i2s->regmap, XTFPGA_I2S_INT_MASK, 0);
622 		regmap_write(i2s->regmap, XTFPGA_I2S_INT_STATUS,
623 			     XTFPGA_I2S_INT_VALID);
624 	}
625 	pm_runtime_disable(&pdev->dev);
626 	if (!pm_runtime_status_suspended(&pdev->dev))
627 		xtfpga_i2s_runtime_suspend(&pdev->dev);
628 	return 0;
629 }
630 
631 #ifdef CONFIG_OF
632 static const struct of_device_id xtfpga_i2s_of_match[] = {
633 	{ .compatible = "cdns,xtfpga-i2s", },
634 	{},
635 };
636 MODULE_DEVICE_TABLE(of, xtfpga_i2s_of_match);
637 #endif
638 
639 static const struct dev_pm_ops xtfpga_i2s_pm_ops = {
640 	SET_RUNTIME_PM_OPS(xtfpga_i2s_runtime_suspend,
641 			   xtfpga_i2s_runtime_resume, NULL)
642 };
643 
644 static struct platform_driver xtfpga_i2s_driver = {
645 	.probe   = xtfpga_i2s_probe,
646 	.remove  = xtfpga_i2s_remove,
647 	.driver  = {
648 		.name = "xtfpga-i2s",
649 		.of_match_table = of_match_ptr(xtfpga_i2s_of_match),
650 		.pm = &xtfpga_i2s_pm_ops,
651 	},
652 };
653 
654 module_platform_driver(xtfpga_i2s_driver);
655 
656 MODULE_AUTHOR("Max Filippov <jcmvbkbc@gmail.com>");
657 MODULE_DESCRIPTION("xtfpga I2S controller driver");
658 MODULE_LICENSE("GPL v2");
659