xref: /openbmc/linux/sound/soc/atmel/atmel_ssc_dai.c (revision e553d2a5)
1 // SPDX-License-Identifier: GPL-2.0-or-later
2 /*
3  * atmel_ssc_dai.c  --  ALSA SoC ATMEL SSC Audio Layer Platform driver
4  *
5  * Copyright (C) 2005 SAN People
6  * Copyright (C) 2008 Atmel
7  *
8  * Author: Sedji Gaouaou <sedji.gaouaou@atmel.com>
9  *         ATMEL CORP.
10  *
11  * Based on at91-ssc.c by
12  * Frank Mandarino <fmandarino@endrelia.com>
13  * Based on pxa2xx Platform drivers by
14  * Liam Girdwood <lrg@slimlogic.co.uk>
15  */
16 
17 #include <linux/init.h>
18 #include <linux/module.h>
19 #include <linux/interrupt.h>
20 #include <linux/device.h>
21 #include <linux/delay.h>
22 #include <linux/clk.h>
23 #include <linux/atmel_pdc.h>
24 
25 #include <linux/atmel-ssc.h>
26 #include <sound/core.h>
27 #include <sound/pcm.h>
28 #include <sound/pcm_params.h>
29 #include <sound/initval.h>
30 #include <sound/soc.h>
31 
32 #include "atmel-pcm.h"
33 #include "atmel_ssc_dai.h"
34 
35 
36 #define NUM_SSC_DEVICES		3
37 
38 /*
39  * SSC PDC registers required by the PCM DMA engine.
40  */
41 static struct atmel_pdc_regs pdc_tx_reg = {
42 	.xpr		= ATMEL_PDC_TPR,
43 	.xcr		= ATMEL_PDC_TCR,
44 	.xnpr		= ATMEL_PDC_TNPR,
45 	.xncr		= ATMEL_PDC_TNCR,
46 };
47 
48 static struct atmel_pdc_regs pdc_rx_reg = {
49 	.xpr		= ATMEL_PDC_RPR,
50 	.xcr		= ATMEL_PDC_RCR,
51 	.xnpr		= ATMEL_PDC_RNPR,
52 	.xncr		= ATMEL_PDC_RNCR,
53 };
54 
55 /*
56  * SSC & PDC status bits for transmit and receive.
57  */
58 static struct atmel_ssc_mask ssc_tx_mask = {
59 	.ssc_enable	= SSC_BIT(CR_TXEN),
60 	.ssc_disable	= SSC_BIT(CR_TXDIS),
61 	.ssc_endx	= SSC_BIT(SR_ENDTX),
62 	.ssc_endbuf	= SSC_BIT(SR_TXBUFE),
63 	.ssc_error	= SSC_BIT(SR_OVRUN),
64 	.pdc_enable	= ATMEL_PDC_TXTEN,
65 	.pdc_disable	= ATMEL_PDC_TXTDIS,
66 };
67 
68 static struct atmel_ssc_mask ssc_rx_mask = {
69 	.ssc_enable	= SSC_BIT(CR_RXEN),
70 	.ssc_disable	= SSC_BIT(CR_RXDIS),
71 	.ssc_endx	= SSC_BIT(SR_ENDRX),
72 	.ssc_endbuf	= SSC_BIT(SR_RXBUFF),
73 	.ssc_error	= SSC_BIT(SR_OVRUN),
74 	.pdc_enable	= ATMEL_PDC_RXTEN,
75 	.pdc_disable	= ATMEL_PDC_RXTDIS,
76 };
77 
78 
79 /*
80  * DMA parameters.
81  */
82 static struct atmel_pcm_dma_params ssc_dma_params[NUM_SSC_DEVICES][2] = {
83 	{{
84 	.name		= "SSC0 PCM out",
85 	.pdc		= &pdc_tx_reg,
86 	.mask		= &ssc_tx_mask,
87 	},
88 	{
89 	.name		= "SSC0 PCM in",
90 	.pdc		= &pdc_rx_reg,
91 	.mask		= &ssc_rx_mask,
92 	} },
93 	{{
94 	.name		= "SSC1 PCM out",
95 	.pdc		= &pdc_tx_reg,
96 	.mask		= &ssc_tx_mask,
97 	},
98 	{
99 	.name		= "SSC1 PCM in",
100 	.pdc		= &pdc_rx_reg,
101 	.mask		= &ssc_rx_mask,
102 	} },
103 	{{
104 	.name		= "SSC2 PCM out",
105 	.pdc		= &pdc_tx_reg,
106 	.mask		= &ssc_tx_mask,
107 	},
108 	{
109 	.name		= "SSC2 PCM in",
110 	.pdc		= &pdc_rx_reg,
111 	.mask		= &ssc_rx_mask,
112 	} },
113 };
114 
115 
116 static struct atmel_ssc_info ssc_info[NUM_SSC_DEVICES] = {
117 	{
118 	.name		= "ssc0",
119 	.lock		= __SPIN_LOCK_UNLOCKED(ssc_info[0].lock),
120 	.dir_mask	= SSC_DIR_MASK_UNUSED,
121 	.initialized	= 0,
122 	},
123 	{
124 	.name		= "ssc1",
125 	.lock		= __SPIN_LOCK_UNLOCKED(ssc_info[1].lock),
126 	.dir_mask	= SSC_DIR_MASK_UNUSED,
127 	.initialized	= 0,
128 	},
129 	{
130 	.name		= "ssc2",
131 	.lock		= __SPIN_LOCK_UNLOCKED(ssc_info[2].lock),
132 	.dir_mask	= SSC_DIR_MASK_UNUSED,
133 	.initialized	= 0,
134 	},
135 };
136 
137 
138 /*
139  * SSC interrupt handler.  Passes PDC interrupts to the DMA
140  * interrupt handler in the PCM driver.
141  */
142 static irqreturn_t atmel_ssc_interrupt(int irq, void *dev_id)
143 {
144 	struct atmel_ssc_info *ssc_p = dev_id;
145 	struct atmel_pcm_dma_params *dma_params;
146 	u32 ssc_sr;
147 	u32 ssc_substream_mask;
148 	int i;
149 
150 	ssc_sr = (unsigned long)ssc_readl(ssc_p->ssc->regs, SR)
151 			& (unsigned long)ssc_readl(ssc_p->ssc->regs, IMR);
152 
153 	/*
154 	 * Loop through the substreams attached to this SSC.  If
155 	 * a DMA-related interrupt occurred on that substream, call
156 	 * the DMA interrupt handler function, if one has been
157 	 * registered in the dma_params structure by the PCM driver.
158 	 */
159 	for (i = 0; i < ARRAY_SIZE(ssc_p->dma_params); i++) {
160 		dma_params = ssc_p->dma_params[i];
161 
162 		if ((dma_params != NULL) &&
163 			(dma_params->dma_intr_handler != NULL)) {
164 			ssc_substream_mask = (dma_params->mask->ssc_endx |
165 					dma_params->mask->ssc_endbuf);
166 			if (ssc_sr & ssc_substream_mask) {
167 				dma_params->dma_intr_handler(ssc_sr,
168 						dma_params->
169 						substream);
170 			}
171 		}
172 	}
173 
174 	return IRQ_HANDLED;
175 }
176 
177 /*
178  * When the bit clock is input, limit the maximum rate according to the
179  * Serial Clock Ratio Considerations section from the SSC documentation:
180  *
181  *   The Transmitter and the Receiver can be programmed to operate
182  *   with the clock signals provided on either the TK or RK pins.
183  *   This allows the SSC to support many slave-mode data transfers.
184  *   In this case, the maximum clock speed allowed on the RK pin is:
185  *   - Peripheral clock divided by 2 if Receiver Frame Synchro is input
186  *   - Peripheral clock divided by 3 if Receiver Frame Synchro is output
187  *   In addition, the maximum clock speed allowed on the TK pin is:
188  *   - Peripheral clock divided by 6 if Transmit Frame Synchro is input
189  *   - Peripheral clock divided by 2 if Transmit Frame Synchro is output
190  *
191  * When the bit clock is output, limit the rate according to the
192  * SSC divider restrictions.
193  */
194 static int atmel_ssc_hw_rule_rate(struct snd_pcm_hw_params *params,
195 				  struct snd_pcm_hw_rule *rule)
196 {
197 	struct atmel_ssc_info *ssc_p = rule->private;
198 	struct ssc_device *ssc = ssc_p->ssc;
199 	struct snd_interval *i = hw_param_interval(params, rule->var);
200 	struct snd_interval t;
201 	struct snd_ratnum r = {
202 		.den_min = 1,
203 		.den_max = 4095,
204 		.den_step = 1,
205 	};
206 	unsigned int num = 0, den = 0;
207 	int frame_size;
208 	int mck_div = 2;
209 	int ret;
210 
211 	frame_size = snd_soc_params_to_frame_size(params);
212 	if (frame_size < 0)
213 		return frame_size;
214 
215 	switch (ssc_p->daifmt & SND_SOC_DAIFMT_MASTER_MASK) {
216 	case SND_SOC_DAIFMT_CBM_CFS:
217 		if ((ssc_p->dir_mask & SSC_DIR_MASK_CAPTURE)
218 		    && ssc->clk_from_rk_pin)
219 			/* Receiver Frame Synchro (i.e. capture)
220 			 * is output (format is _CFS) and the RK pin
221 			 * is used for input (format is _CBM_).
222 			 */
223 			mck_div = 3;
224 		break;
225 
226 	case SND_SOC_DAIFMT_CBM_CFM:
227 		if ((ssc_p->dir_mask & SSC_DIR_MASK_PLAYBACK)
228 		    && !ssc->clk_from_rk_pin)
229 			/* Transmit Frame Synchro (i.e. playback)
230 			 * is input (format is _CFM) and the TK pin
231 			 * is used for input (format _CBM_ but not
232 			 * using the RK pin).
233 			 */
234 			mck_div = 6;
235 		break;
236 	}
237 
238 	switch (ssc_p->daifmt & SND_SOC_DAIFMT_MASTER_MASK) {
239 	case SND_SOC_DAIFMT_CBS_CFS:
240 		r.num = ssc_p->mck_rate / mck_div / frame_size;
241 
242 		ret = snd_interval_ratnum(i, 1, &r, &num, &den);
243 		if (ret >= 0 && den && rule->var == SNDRV_PCM_HW_PARAM_RATE) {
244 			params->rate_num = num;
245 			params->rate_den = den;
246 		}
247 		break;
248 
249 	case SND_SOC_DAIFMT_CBM_CFS:
250 	case SND_SOC_DAIFMT_CBM_CFM:
251 		t.min = 8000;
252 		t.max = ssc_p->mck_rate / mck_div / frame_size;
253 		t.openmin = t.openmax = 0;
254 		t.integer = 0;
255 		ret = snd_interval_refine(i, &t);
256 		break;
257 
258 	default:
259 		ret = -EINVAL;
260 		break;
261 	}
262 
263 	return ret;
264 }
265 
266 /*-------------------------------------------------------------------------*\
267  * DAI functions
268 \*-------------------------------------------------------------------------*/
269 /*
270  * Startup.  Only that one substream allowed in each direction.
271  */
272 static int atmel_ssc_startup(struct snd_pcm_substream *substream,
273 			     struct snd_soc_dai *dai)
274 {
275 	struct platform_device *pdev = to_platform_device(dai->dev);
276 	struct atmel_ssc_info *ssc_p = &ssc_info[pdev->id];
277 	struct atmel_pcm_dma_params *dma_params;
278 	int dir, dir_mask;
279 	int ret;
280 
281 	pr_debug("atmel_ssc_startup: SSC_SR=0x%x\n",
282 		ssc_readl(ssc_p->ssc->regs, SR));
283 
284 	/* Enable PMC peripheral clock for this SSC */
285 	pr_debug("atmel_ssc_dai: Starting clock\n");
286 	clk_enable(ssc_p->ssc->clk);
287 	ssc_p->mck_rate = clk_get_rate(ssc_p->ssc->clk);
288 
289 	/* Reset the SSC unless initialized to keep it in a clean state */
290 	if (!ssc_p->initialized)
291 		ssc_writel(ssc_p->ssc->regs, CR, SSC_BIT(CR_SWRST));
292 
293 	if (substream->stream == SNDRV_PCM_STREAM_PLAYBACK) {
294 		dir = 0;
295 		dir_mask = SSC_DIR_MASK_PLAYBACK;
296 	} else {
297 		dir = 1;
298 		dir_mask = SSC_DIR_MASK_CAPTURE;
299 	}
300 
301 	ret = snd_pcm_hw_rule_add(substream->runtime, 0,
302 				  SNDRV_PCM_HW_PARAM_RATE,
303 				  atmel_ssc_hw_rule_rate,
304 				  ssc_p,
305 				  SNDRV_PCM_HW_PARAM_FRAME_BITS,
306 				  SNDRV_PCM_HW_PARAM_CHANNELS, -1);
307 	if (ret < 0) {
308 		dev_err(dai->dev, "Failed to specify rate rule: %d\n", ret);
309 		return ret;
310 	}
311 
312 	dma_params = &ssc_dma_params[pdev->id][dir];
313 	dma_params->ssc = ssc_p->ssc;
314 	dma_params->substream = substream;
315 
316 	ssc_p->dma_params[dir] = dma_params;
317 
318 	snd_soc_dai_set_dma_data(dai, substream, dma_params);
319 
320 	spin_lock_irq(&ssc_p->lock);
321 	if (ssc_p->dir_mask & dir_mask) {
322 		spin_unlock_irq(&ssc_p->lock);
323 		return -EBUSY;
324 	}
325 	ssc_p->dir_mask |= dir_mask;
326 	spin_unlock_irq(&ssc_p->lock);
327 
328 	return 0;
329 }
330 
331 /*
332  * Shutdown.  Clear DMA parameters and shutdown the SSC if there
333  * are no other substreams open.
334  */
335 static void atmel_ssc_shutdown(struct snd_pcm_substream *substream,
336 			       struct snd_soc_dai *dai)
337 {
338 	struct platform_device *pdev = to_platform_device(dai->dev);
339 	struct atmel_ssc_info *ssc_p = &ssc_info[pdev->id];
340 	struct atmel_pcm_dma_params *dma_params;
341 	int dir, dir_mask;
342 
343 	if (substream->stream == SNDRV_PCM_STREAM_PLAYBACK)
344 		dir = 0;
345 	else
346 		dir = 1;
347 
348 	dma_params = ssc_p->dma_params[dir];
349 
350 	if (dma_params != NULL) {
351 		dma_params->ssc = NULL;
352 		dma_params->substream = NULL;
353 		ssc_p->dma_params[dir] = NULL;
354 	}
355 
356 	dir_mask = 1 << dir;
357 
358 	spin_lock_irq(&ssc_p->lock);
359 	ssc_p->dir_mask &= ~dir_mask;
360 	if (!ssc_p->dir_mask) {
361 		if (ssc_p->initialized) {
362 			free_irq(ssc_p->ssc->irq, ssc_p);
363 			ssc_p->initialized = 0;
364 		}
365 
366 		/* Reset the SSC */
367 		ssc_writel(ssc_p->ssc->regs, CR, SSC_BIT(CR_SWRST));
368 		/* Clear the SSC dividers */
369 		ssc_p->cmr_div = ssc_p->tcmr_period = ssc_p->rcmr_period = 0;
370 		ssc_p->forced_divider = 0;
371 	}
372 	spin_unlock_irq(&ssc_p->lock);
373 
374 	/* Shutdown the SSC clock. */
375 	pr_debug("atmel_ssc_dai: Stopping clock\n");
376 	clk_disable(ssc_p->ssc->clk);
377 }
378 
379 
380 /*
381  * Record the DAI format for use in hw_params().
382  */
383 static int atmel_ssc_set_dai_fmt(struct snd_soc_dai *cpu_dai,
384 		unsigned int fmt)
385 {
386 	struct platform_device *pdev = to_platform_device(cpu_dai->dev);
387 	struct atmel_ssc_info *ssc_p = &ssc_info[pdev->id];
388 
389 	ssc_p->daifmt = fmt;
390 	return 0;
391 }
392 
393 /*
394  * Record SSC clock dividers for use in hw_params().
395  */
396 static int atmel_ssc_set_dai_clkdiv(struct snd_soc_dai *cpu_dai,
397 	int div_id, int div)
398 {
399 	struct platform_device *pdev = to_platform_device(cpu_dai->dev);
400 	struct atmel_ssc_info *ssc_p = &ssc_info[pdev->id];
401 
402 	switch (div_id) {
403 	case ATMEL_SSC_CMR_DIV:
404 		/*
405 		 * The same master clock divider is used for both
406 		 * transmit and receive, so if a value has already
407 		 * been set, it must match this value.
408 		 */
409 		if (ssc_p->dir_mask !=
410 			(SSC_DIR_MASK_PLAYBACK | SSC_DIR_MASK_CAPTURE))
411 			ssc_p->cmr_div = div;
412 		else if (ssc_p->cmr_div == 0)
413 			ssc_p->cmr_div = div;
414 		else
415 			if (div != ssc_p->cmr_div)
416 				return -EBUSY;
417 		ssc_p->forced_divider |= BIT(ATMEL_SSC_CMR_DIV);
418 		break;
419 
420 	case ATMEL_SSC_TCMR_PERIOD:
421 		ssc_p->tcmr_period = div;
422 		ssc_p->forced_divider |= BIT(ATMEL_SSC_TCMR_PERIOD);
423 		break;
424 
425 	case ATMEL_SSC_RCMR_PERIOD:
426 		ssc_p->rcmr_period = div;
427 		ssc_p->forced_divider |= BIT(ATMEL_SSC_RCMR_PERIOD);
428 		break;
429 
430 	default:
431 		return -EINVAL;
432 	}
433 
434 	return 0;
435 }
436 
437 /* Is the cpu-dai master of the frame clock? */
438 static int atmel_ssc_cfs(struct atmel_ssc_info *ssc_p)
439 {
440 	switch (ssc_p->daifmt & SND_SOC_DAIFMT_MASTER_MASK) {
441 	case SND_SOC_DAIFMT_CBM_CFS:
442 	case SND_SOC_DAIFMT_CBS_CFS:
443 		return 1;
444 	}
445 	return 0;
446 }
447 
448 /* Is the cpu-dai master of the bit clock? */
449 static int atmel_ssc_cbs(struct atmel_ssc_info *ssc_p)
450 {
451 	switch (ssc_p->daifmt & SND_SOC_DAIFMT_MASTER_MASK) {
452 	case SND_SOC_DAIFMT_CBS_CFM:
453 	case SND_SOC_DAIFMT_CBS_CFS:
454 		return 1;
455 	}
456 	return 0;
457 }
458 
459 /*
460  * Configure the SSC.
461  */
462 static int atmel_ssc_hw_params(struct snd_pcm_substream *substream,
463 	struct snd_pcm_hw_params *params,
464 	struct snd_soc_dai *dai)
465 {
466 	struct platform_device *pdev = to_platform_device(dai->dev);
467 	int id = pdev->id;
468 	struct atmel_ssc_info *ssc_p = &ssc_info[id];
469 	struct ssc_device *ssc = ssc_p->ssc;
470 	struct atmel_pcm_dma_params *dma_params;
471 	int dir, channels, bits;
472 	u32 tfmr, rfmr, tcmr, rcmr;
473 	int ret;
474 	int fslen, fslen_ext, fs_osync, fs_edge;
475 	u32 cmr_div;
476 	u32 tcmr_period;
477 	u32 rcmr_period;
478 
479 	/*
480 	 * Currently, there is only one set of dma params for
481 	 * each direction.  If more are added, this code will
482 	 * have to be changed to select the proper set.
483 	 */
484 	if (substream->stream == SNDRV_PCM_STREAM_PLAYBACK)
485 		dir = 0;
486 	else
487 		dir = 1;
488 
489 	/*
490 	 * If the cpu dai should provide BCLK, but noone has provided the
491 	 * divider needed for that to work, fall back to something sensible.
492 	 */
493 	cmr_div = ssc_p->cmr_div;
494 	if (!(ssc_p->forced_divider & BIT(ATMEL_SSC_CMR_DIV)) &&
495 	    atmel_ssc_cbs(ssc_p)) {
496 		int bclk_rate = snd_soc_params_to_bclk(params);
497 
498 		if (bclk_rate < 0) {
499 			dev_err(dai->dev, "unable to calculate cmr_div: %d\n",
500 				bclk_rate);
501 			return bclk_rate;
502 		}
503 
504 		cmr_div = DIV_ROUND_CLOSEST(ssc_p->mck_rate, 2 * bclk_rate);
505 	}
506 
507 	/*
508 	 * If the cpu dai should provide LRCLK, but noone has provided the
509 	 * dividers needed for that to work, fall back to something sensible.
510 	 */
511 	tcmr_period = ssc_p->tcmr_period;
512 	rcmr_period = ssc_p->rcmr_period;
513 	if (atmel_ssc_cfs(ssc_p)) {
514 		int frame_size = snd_soc_params_to_frame_size(params);
515 
516 		if (frame_size < 0) {
517 			dev_err(dai->dev,
518 				"unable to calculate tx/rx cmr_period: %d\n",
519 				frame_size);
520 			return frame_size;
521 		}
522 
523 		if (!(ssc_p->forced_divider & BIT(ATMEL_SSC_TCMR_PERIOD)))
524 			tcmr_period = frame_size / 2 - 1;
525 		if (!(ssc_p->forced_divider & BIT(ATMEL_SSC_RCMR_PERIOD)))
526 			rcmr_period = frame_size / 2 - 1;
527 	}
528 
529 	dma_params = ssc_p->dma_params[dir];
530 
531 	channels = params_channels(params);
532 
533 	/*
534 	 * Determine sample size in bits and the PDC increment.
535 	 */
536 	switch (params_format(params)) {
537 	case SNDRV_PCM_FORMAT_S8:
538 		bits = 8;
539 		dma_params->pdc_xfer_size = 1;
540 		break;
541 	case SNDRV_PCM_FORMAT_S16_LE:
542 		bits = 16;
543 		dma_params->pdc_xfer_size = 2;
544 		break;
545 	case SNDRV_PCM_FORMAT_S24_LE:
546 		bits = 24;
547 		dma_params->pdc_xfer_size = 4;
548 		break;
549 	case SNDRV_PCM_FORMAT_S32_LE:
550 		bits = 32;
551 		dma_params->pdc_xfer_size = 4;
552 		break;
553 	default:
554 		printk(KERN_WARNING "atmel_ssc_dai: unsupported PCM format");
555 		return -EINVAL;
556 	}
557 
558 	/*
559 	 * Compute SSC register settings.
560 	 */
561 
562 	fslen_ext = (bits - 1) / 16;
563 	fslen = (bits - 1) % 16;
564 
565 	switch (ssc_p->daifmt & SND_SOC_DAIFMT_FORMAT_MASK) {
566 
567 	case SND_SOC_DAIFMT_LEFT_J:
568 		fs_osync = SSC_FSOS_POSITIVE;
569 		fs_edge = SSC_START_RISING_RF;
570 
571 		rcmr =	  SSC_BF(RCMR_STTDLY, 0);
572 		tcmr =	  SSC_BF(TCMR_STTDLY, 0);
573 
574 		break;
575 
576 	case SND_SOC_DAIFMT_I2S:
577 		fs_osync = SSC_FSOS_NEGATIVE;
578 		fs_edge = SSC_START_FALLING_RF;
579 
580 		rcmr =	  SSC_BF(RCMR_STTDLY, 1);
581 		tcmr =	  SSC_BF(TCMR_STTDLY, 1);
582 
583 		break;
584 
585 	case SND_SOC_DAIFMT_DSP_A:
586 		/*
587 		 * DSP/PCM Mode A format
588 		 *
589 		 * Data is transferred on first BCLK after LRC pulse rising
590 		 * edge.If stereo, the right channel data is contiguous with
591 		 * the left channel data.
592 		 */
593 		fs_osync = SSC_FSOS_POSITIVE;
594 		fs_edge = SSC_START_RISING_RF;
595 		fslen = fslen_ext = 0;
596 
597 		rcmr =	  SSC_BF(RCMR_STTDLY, 1);
598 		tcmr =	  SSC_BF(TCMR_STTDLY, 1);
599 
600 		break;
601 
602 	default:
603 		printk(KERN_WARNING "atmel_ssc_dai: unsupported DAI format 0x%x\n",
604 			ssc_p->daifmt);
605 		return -EINVAL;
606 	}
607 
608 	if (!atmel_ssc_cfs(ssc_p)) {
609 		fslen = fslen_ext = 0;
610 		rcmr_period = tcmr_period = 0;
611 		fs_osync = SSC_FSOS_NONE;
612 	}
613 
614 	rcmr |=	  SSC_BF(RCMR_START, fs_edge);
615 	tcmr |=	  SSC_BF(TCMR_START, fs_edge);
616 
617 	if (atmel_ssc_cbs(ssc_p)) {
618 		/*
619 		 * SSC provides BCLK
620 		 *
621 		 * The SSC transmit and receive clocks are generated from the
622 		 * MCK divider, and the BCLK signal is output
623 		 * on the SSC TK line.
624 		 */
625 		rcmr |=	  SSC_BF(RCMR_CKS, SSC_CKS_DIV)
626 			| SSC_BF(RCMR_CKO, SSC_CKO_NONE);
627 
628 		tcmr |=	  SSC_BF(TCMR_CKS, SSC_CKS_DIV)
629 			| SSC_BF(TCMR_CKO, SSC_CKO_CONTINUOUS);
630 	} else {
631 		rcmr |=	  SSC_BF(RCMR_CKS, ssc->clk_from_rk_pin ?
632 					SSC_CKS_PIN : SSC_CKS_CLOCK)
633 			| SSC_BF(RCMR_CKO, SSC_CKO_NONE);
634 
635 		tcmr |=	  SSC_BF(TCMR_CKS, ssc->clk_from_rk_pin ?
636 					SSC_CKS_CLOCK : SSC_CKS_PIN)
637 			| SSC_BF(TCMR_CKO, SSC_CKO_NONE);
638 	}
639 
640 	rcmr |=	  SSC_BF(RCMR_PERIOD, rcmr_period)
641 		| SSC_BF(RCMR_CKI, SSC_CKI_RISING);
642 
643 	tcmr |=   SSC_BF(TCMR_PERIOD, tcmr_period)
644 		| SSC_BF(TCMR_CKI, SSC_CKI_FALLING);
645 
646 	rfmr =    SSC_BF(RFMR_FSLEN_EXT, fslen_ext)
647 		| SSC_BF(RFMR_FSEDGE, SSC_FSEDGE_POSITIVE)
648 		| SSC_BF(RFMR_FSOS, fs_osync)
649 		| SSC_BF(RFMR_FSLEN, fslen)
650 		| SSC_BF(RFMR_DATNB, (channels - 1))
651 		| SSC_BIT(RFMR_MSBF)
652 		| SSC_BF(RFMR_LOOP, 0)
653 		| SSC_BF(RFMR_DATLEN, (bits - 1));
654 
655 	tfmr =    SSC_BF(TFMR_FSLEN_EXT, fslen_ext)
656 		| SSC_BF(TFMR_FSEDGE, SSC_FSEDGE_POSITIVE)
657 		| SSC_BF(TFMR_FSDEN, 0)
658 		| SSC_BF(TFMR_FSOS, fs_osync)
659 		| SSC_BF(TFMR_FSLEN, fslen)
660 		| SSC_BF(TFMR_DATNB, (channels - 1))
661 		| SSC_BIT(TFMR_MSBF)
662 		| SSC_BF(TFMR_DATDEF, 0)
663 		| SSC_BF(TFMR_DATLEN, (bits - 1));
664 
665 	if (fslen_ext && !ssc->pdata->has_fslen_ext) {
666 		dev_err(dai->dev, "sample size %d is too large for SSC device\n",
667 			bits);
668 		return -EINVAL;
669 	}
670 
671 	pr_debug("atmel_ssc_hw_params: "
672 			"RCMR=%08x RFMR=%08x TCMR=%08x TFMR=%08x\n",
673 			rcmr, rfmr, tcmr, tfmr);
674 
675 	if (!ssc_p->initialized) {
676 		if (!ssc_p->ssc->pdata->use_dma) {
677 			ssc_writel(ssc_p->ssc->regs, PDC_RPR, 0);
678 			ssc_writel(ssc_p->ssc->regs, PDC_RCR, 0);
679 			ssc_writel(ssc_p->ssc->regs, PDC_RNPR, 0);
680 			ssc_writel(ssc_p->ssc->regs, PDC_RNCR, 0);
681 
682 			ssc_writel(ssc_p->ssc->regs, PDC_TPR, 0);
683 			ssc_writel(ssc_p->ssc->regs, PDC_TCR, 0);
684 			ssc_writel(ssc_p->ssc->regs, PDC_TNPR, 0);
685 			ssc_writel(ssc_p->ssc->regs, PDC_TNCR, 0);
686 		}
687 
688 		ret = request_irq(ssc_p->ssc->irq, atmel_ssc_interrupt, 0,
689 				ssc_p->name, ssc_p);
690 		if (ret < 0) {
691 			printk(KERN_WARNING
692 					"atmel_ssc_dai: request_irq failure\n");
693 			pr_debug("Atmel_ssc_dai: Stopping clock\n");
694 			clk_disable(ssc_p->ssc->clk);
695 			return ret;
696 		}
697 
698 		ssc_p->initialized = 1;
699 	}
700 
701 	/* set SSC clock mode register */
702 	ssc_writel(ssc_p->ssc->regs, CMR, cmr_div);
703 
704 	/* set receive clock mode and format */
705 	ssc_writel(ssc_p->ssc->regs, RCMR, rcmr);
706 	ssc_writel(ssc_p->ssc->regs, RFMR, rfmr);
707 
708 	/* set transmit clock mode and format */
709 	ssc_writel(ssc_p->ssc->regs, TCMR, tcmr);
710 	ssc_writel(ssc_p->ssc->regs, TFMR, tfmr);
711 
712 	pr_debug("atmel_ssc_dai,hw_params: SSC initialized\n");
713 	return 0;
714 }
715 
716 
717 static int atmel_ssc_prepare(struct snd_pcm_substream *substream,
718 			     struct snd_soc_dai *dai)
719 {
720 	struct platform_device *pdev = to_platform_device(dai->dev);
721 	struct atmel_ssc_info *ssc_p = &ssc_info[pdev->id];
722 	struct atmel_pcm_dma_params *dma_params;
723 	int dir;
724 
725 	if (substream->stream == SNDRV_PCM_STREAM_PLAYBACK)
726 		dir = 0;
727 	else
728 		dir = 1;
729 
730 	dma_params = ssc_p->dma_params[dir];
731 
732 	ssc_writel(ssc_p->ssc->regs, CR, dma_params->mask->ssc_disable);
733 	ssc_writel(ssc_p->ssc->regs, IDR, dma_params->mask->ssc_error);
734 
735 	pr_debug("%s enabled SSC_SR=0x%08x\n",
736 			dir ? "receive" : "transmit",
737 			ssc_readl(ssc_p->ssc->regs, SR));
738 	return 0;
739 }
740 
741 static int atmel_ssc_trigger(struct snd_pcm_substream *substream,
742 			     int cmd, struct snd_soc_dai *dai)
743 {
744 	struct platform_device *pdev = to_platform_device(dai->dev);
745 	struct atmel_ssc_info *ssc_p = &ssc_info[pdev->id];
746 	struct atmel_pcm_dma_params *dma_params;
747 	int dir;
748 
749 	if (substream->stream == SNDRV_PCM_STREAM_PLAYBACK)
750 		dir = 0;
751 	else
752 		dir = 1;
753 
754 	dma_params = ssc_p->dma_params[dir];
755 
756 	switch (cmd) {
757 	case SNDRV_PCM_TRIGGER_START:
758 	case SNDRV_PCM_TRIGGER_RESUME:
759 	case SNDRV_PCM_TRIGGER_PAUSE_RELEASE:
760 		ssc_writel(ssc_p->ssc->regs, CR, dma_params->mask->ssc_enable);
761 		break;
762 	default:
763 		ssc_writel(ssc_p->ssc->regs, CR, dma_params->mask->ssc_disable);
764 		break;
765 	}
766 
767 	return 0;
768 }
769 
770 #ifdef CONFIG_PM
771 static int atmel_ssc_suspend(struct snd_soc_dai *cpu_dai)
772 {
773 	struct atmel_ssc_info *ssc_p;
774 	struct platform_device *pdev = to_platform_device(cpu_dai->dev);
775 
776 	if (!cpu_dai->active)
777 		return 0;
778 
779 	ssc_p = &ssc_info[pdev->id];
780 
781 	/* Save the status register before disabling transmit and receive */
782 	ssc_p->ssc_state.ssc_sr = ssc_readl(ssc_p->ssc->regs, SR);
783 	ssc_writel(ssc_p->ssc->regs, CR, SSC_BIT(CR_TXDIS) | SSC_BIT(CR_RXDIS));
784 
785 	/* Save the current interrupt mask, then disable unmasked interrupts */
786 	ssc_p->ssc_state.ssc_imr = ssc_readl(ssc_p->ssc->regs, IMR);
787 	ssc_writel(ssc_p->ssc->regs, IDR, ssc_p->ssc_state.ssc_imr);
788 
789 	ssc_p->ssc_state.ssc_cmr = ssc_readl(ssc_p->ssc->regs, CMR);
790 	ssc_p->ssc_state.ssc_rcmr = ssc_readl(ssc_p->ssc->regs, RCMR);
791 	ssc_p->ssc_state.ssc_rfmr = ssc_readl(ssc_p->ssc->regs, RFMR);
792 	ssc_p->ssc_state.ssc_tcmr = ssc_readl(ssc_p->ssc->regs, TCMR);
793 	ssc_p->ssc_state.ssc_tfmr = ssc_readl(ssc_p->ssc->regs, TFMR);
794 
795 	return 0;
796 }
797 
798 
799 
800 static int atmel_ssc_resume(struct snd_soc_dai *cpu_dai)
801 {
802 	struct atmel_ssc_info *ssc_p;
803 	struct platform_device *pdev = to_platform_device(cpu_dai->dev);
804 	u32 cr;
805 
806 	if (!cpu_dai->active)
807 		return 0;
808 
809 	ssc_p = &ssc_info[pdev->id];
810 
811 	/* restore SSC register settings */
812 	ssc_writel(ssc_p->ssc->regs, TFMR, ssc_p->ssc_state.ssc_tfmr);
813 	ssc_writel(ssc_p->ssc->regs, TCMR, ssc_p->ssc_state.ssc_tcmr);
814 	ssc_writel(ssc_p->ssc->regs, RFMR, ssc_p->ssc_state.ssc_rfmr);
815 	ssc_writel(ssc_p->ssc->regs, RCMR, ssc_p->ssc_state.ssc_rcmr);
816 	ssc_writel(ssc_p->ssc->regs, CMR, ssc_p->ssc_state.ssc_cmr);
817 
818 	/* re-enable interrupts */
819 	ssc_writel(ssc_p->ssc->regs, IER, ssc_p->ssc_state.ssc_imr);
820 
821 	/* Re-enable receive and transmit as appropriate */
822 	cr = 0;
823 	cr |=
824 	    (ssc_p->ssc_state.ssc_sr & SSC_BIT(SR_RXEN)) ? SSC_BIT(CR_RXEN) : 0;
825 	cr |=
826 	    (ssc_p->ssc_state.ssc_sr & SSC_BIT(SR_TXEN)) ? SSC_BIT(CR_TXEN) : 0;
827 	ssc_writel(ssc_p->ssc->regs, CR, cr);
828 
829 	return 0;
830 }
831 #else /* CONFIG_PM */
832 #  define atmel_ssc_suspend	NULL
833 #  define atmel_ssc_resume	NULL
834 #endif /* CONFIG_PM */
835 
836 #define ATMEL_SSC_FORMATS (SNDRV_PCM_FMTBIT_S8     | SNDRV_PCM_FMTBIT_S16_LE |\
837 			  SNDRV_PCM_FMTBIT_S24_LE | SNDRV_PCM_FMTBIT_S32_LE)
838 
839 static const struct snd_soc_dai_ops atmel_ssc_dai_ops = {
840 	.startup	= atmel_ssc_startup,
841 	.shutdown	= atmel_ssc_shutdown,
842 	.prepare	= atmel_ssc_prepare,
843 	.trigger	= atmel_ssc_trigger,
844 	.hw_params	= atmel_ssc_hw_params,
845 	.set_fmt	= atmel_ssc_set_dai_fmt,
846 	.set_clkdiv	= atmel_ssc_set_dai_clkdiv,
847 };
848 
849 static struct snd_soc_dai_driver atmel_ssc_dai = {
850 		.suspend = atmel_ssc_suspend,
851 		.resume = atmel_ssc_resume,
852 		.playback = {
853 			.channels_min = 1,
854 			.channels_max = 2,
855 			.rates = SNDRV_PCM_RATE_CONTINUOUS,
856 			.rate_min = 8000,
857 			.rate_max = 384000,
858 			.formats = ATMEL_SSC_FORMATS,},
859 		.capture = {
860 			.channels_min = 1,
861 			.channels_max = 2,
862 			.rates = SNDRV_PCM_RATE_CONTINUOUS,
863 			.rate_min = 8000,
864 			.rate_max = 384000,
865 			.formats = ATMEL_SSC_FORMATS,},
866 		.ops = &atmel_ssc_dai_ops,
867 };
868 
869 static const struct snd_soc_component_driver atmel_ssc_component = {
870 	.name		= "atmel-ssc",
871 };
872 
873 static int asoc_ssc_init(struct device *dev)
874 {
875 	struct ssc_device *ssc = dev_get_drvdata(dev);
876 	int ret;
877 
878 	ret = devm_snd_soc_register_component(dev, &atmel_ssc_component,
879 					 &atmel_ssc_dai, 1);
880 	if (ret) {
881 		dev_err(dev, "Could not register DAI: %d\n", ret);
882 		return ret;
883 	}
884 
885 	if (ssc->pdata->use_dma)
886 		ret = atmel_pcm_dma_platform_register(dev);
887 	else
888 		ret = atmel_pcm_pdc_platform_register(dev);
889 
890 	if (ret) {
891 		dev_err(dev, "Could not register PCM: %d\n", ret);
892 		return ret;
893 	}
894 
895 	return 0;
896 }
897 
898 /**
899  * atmel_ssc_set_audio - Allocate the specified SSC for audio use.
900  */
901 int atmel_ssc_set_audio(int ssc_id)
902 {
903 	struct ssc_device *ssc;
904 	int ret;
905 
906 	/* If we can grab the SSC briefly to parent the DAI device off it */
907 	ssc = ssc_request(ssc_id);
908 	if (IS_ERR(ssc)) {
909 		pr_err("Unable to parent ASoC SSC DAI on SSC: %ld\n",
910 			PTR_ERR(ssc));
911 		return PTR_ERR(ssc);
912 	} else {
913 		ssc_info[ssc_id].ssc = ssc;
914 	}
915 
916 	ret = asoc_ssc_init(&ssc->pdev->dev);
917 
918 	return ret;
919 }
920 EXPORT_SYMBOL_GPL(atmel_ssc_set_audio);
921 
922 void atmel_ssc_put_audio(int ssc_id)
923 {
924 	struct ssc_device *ssc = ssc_info[ssc_id].ssc;
925 
926 	ssc_free(ssc);
927 }
928 EXPORT_SYMBOL_GPL(atmel_ssc_put_audio);
929 
930 /* Module information */
931 MODULE_AUTHOR("Sedji Gaouaou, sedji.gaouaou@atmel.com, www.atmel.com");
932 MODULE_DESCRIPTION("ATMEL SSC ASoC Interface");
933 MODULE_LICENSE("GPL");
934