xref: /openbmc/linux/sound/soc/fsl/fsl_ssi.c (revision a09d2831)
1 /*
2  * Freescale SSI ALSA SoC Digital Audio Interface (DAI) driver
3  *
4  * Author: Timur Tabi <timur@freescale.com>
5  *
6  * Copyright 2007-2008 Freescale Semiconductor, Inc.  This file is licensed
7  * under the terms of the GNU General Public License version 2.  This
8  * program is licensed "as is" without any warranty of any kind, whether
9  * express or implied.
10  */
11 
12 #include <linux/init.h>
13 #include <linux/module.h>
14 #include <linux/interrupt.h>
15 #include <linux/device.h>
16 #include <linux/delay.h>
17 
18 #include <sound/core.h>
19 #include <sound/pcm.h>
20 #include <sound/pcm_params.h>
21 #include <sound/initval.h>
22 #include <sound/soc.h>
23 
24 #include <asm/immap_86xx.h>
25 
26 #include "fsl_ssi.h"
27 
28 /**
29  * FSLSSI_I2S_RATES: sample rates supported by the I2S
30  *
31  * This driver currently only supports the SSI running in I2S slave mode,
32  * which means the codec determines the sample rate.  Therefore, we tell
33  * ALSA that we support all rates and let the codec driver decide what rates
34  * are really supported.
35  */
36 #define FSLSSI_I2S_RATES (SNDRV_PCM_RATE_5512 | SNDRV_PCM_RATE_8000_192000 | \
37 			  SNDRV_PCM_RATE_CONTINUOUS)
38 
39 /**
40  * FSLSSI_I2S_FORMATS: audio formats supported by the SSI
41  *
42  * This driver currently only supports the SSI running in I2S slave mode.
43  *
44  * The SSI has a limitation in that the samples must be in the same byte
45  * order as the host CPU.  This is because when multiple bytes are written
46  * to the STX register, the bytes and bits must be written in the same
47  * order.  The STX is a shift register, so all the bits need to be aligned
48  * (bit-endianness must match byte-endianness).  Processors typically write
49  * the bits within a byte in the same order that the bytes of a word are
50  * written in.  So if the host CPU is big-endian, then only big-endian
51  * samples will be written to STX properly.
52  */
53 #ifdef __BIG_ENDIAN
54 #define FSLSSI_I2S_FORMATS (SNDRV_PCM_FMTBIT_S8 | SNDRV_PCM_FMTBIT_S16_BE | \
55 	 SNDRV_PCM_FMTBIT_S18_3BE | SNDRV_PCM_FMTBIT_S20_3BE | \
56 	 SNDRV_PCM_FMTBIT_S24_3BE | SNDRV_PCM_FMTBIT_S24_BE)
57 #else
58 #define FSLSSI_I2S_FORMATS (SNDRV_PCM_FMTBIT_S8 | SNDRV_PCM_FMTBIT_S16_LE | \
59 	 SNDRV_PCM_FMTBIT_S18_3LE | SNDRV_PCM_FMTBIT_S20_3LE | \
60 	 SNDRV_PCM_FMTBIT_S24_3LE | SNDRV_PCM_FMTBIT_S24_LE)
61 #endif
62 
63 /* SIER bitflag of interrupts to enable */
64 #define SIER_FLAGS (CCSR_SSI_SIER_TFRC_EN | CCSR_SSI_SIER_TDMAE | \
65 		    CCSR_SSI_SIER_TIE | CCSR_SSI_SIER_TUE0_EN | \
66 		    CCSR_SSI_SIER_TUE1_EN | CCSR_SSI_SIER_RFRC_EN | \
67 		    CCSR_SSI_SIER_RDMAE | CCSR_SSI_SIER_RIE | \
68 		    CCSR_SSI_SIER_ROE0_EN | CCSR_SSI_SIER_ROE1_EN)
69 
70 /**
71  * fsl_ssi_private: per-SSI private data
72  *
73  * @name: short name for this device ("SSI0", "SSI1", etc)
74  * @ssi: pointer to the SSI's registers
75  * @ssi_phys: physical address of the SSI registers
76  * @irq: IRQ of this SSI
77  * @first_stream: pointer to the stream that was opened first
78  * @second_stream: pointer to second stream
79  * @dev: struct device pointer
80  * @playback: the number of playback streams opened
81  * @capture: the number of capture streams opened
82  * @asynchronous: 0=synchronous mode, 1=asynchronous mode
83  * @cpu_dai: the CPU DAI for this device
84  * @dev_attr: the sysfs device attribute structure
85  * @stats: SSI statistics
86  */
87 struct fsl_ssi_private {
88 	char name[8];
89 	struct ccsr_ssi __iomem *ssi;
90 	dma_addr_t ssi_phys;
91 	unsigned int irq;
92 	struct snd_pcm_substream *first_stream;
93 	struct snd_pcm_substream *second_stream;
94 	struct device *dev;
95 	unsigned int playback;
96 	unsigned int capture;
97 	int asynchronous;
98 	struct snd_soc_dai cpu_dai;
99 	struct device_attribute dev_attr;
100 
101 	struct {
102 		unsigned int rfrc;
103 		unsigned int tfrc;
104 		unsigned int cmdau;
105 		unsigned int cmddu;
106 		unsigned int rxt;
107 		unsigned int rdr1;
108 		unsigned int rdr0;
109 		unsigned int tde1;
110 		unsigned int tde0;
111 		unsigned int roe1;
112 		unsigned int roe0;
113 		unsigned int tue1;
114 		unsigned int tue0;
115 		unsigned int tfs;
116 		unsigned int rfs;
117 		unsigned int tls;
118 		unsigned int rls;
119 		unsigned int rff1;
120 		unsigned int rff0;
121 		unsigned int tfe1;
122 		unsigned int tfe0;
123 	} stats;
124 };
125 
126 /**
127  * fsl_ssi_isr: SSI interrupt handler
128  *
129  * Although it's possible to use the interrupt handler to send and receive
130  * data to/from the SSI, we use the DMA instead.  Programming is more
131  * complicated, but the performance is much better.
132  *
133  * This interrupt handler is used only to gather statistics.
134  *
135  * @irq: IRQ of the SSI device
136  * @dev_id: pointer to the ssi_private structure for this SSI device
137  */
138 static irqreturn_t fsl_ssi_isr(int irq, void *dev_id)
139 {
140 	struct fsl_ssi_private *ssi_private = dev_id;
141 	struct ccsr_ssi __iomem *ssi = ssi_private->ssi;
142 	irqreturn_t ret = IRQ_NONE;
143 	__be32 sisr;
144 	__be32 sisr2 = 0;
145 
146 	/* We got an interrupt, so read the status register to see what we
147 	   were interrupted for.  We mask it with the Interrupt Enable register
148 	   so that we only check for events that we're interested in.
149 	 */
150 	sisr = in_be32(&ssi->sisr) & SIER_FLAGS;
151 
152 	if (sisr & CCSR_SSI_SISR_RFRC) {
153 		ssi_private->stats.rfrc++;
154 		sisr2 |= CCSR_SSI_SISR_RFRC;
155 		ret = IRQ_HANDLED;
156 	}
157 
158 	if (sisr & CCSR_SSI_SISR_TFRC) {
159 		ssi_private->stats.tfrc++;
160 		sisr2 |= CCSR_SSI_SISR_TFRC;
161 		ret = IRQ_HANDLED;
162 	}
163 
164 	if (sisr & CCSR_SSI_SISR_CMDAU) {
165 		ssi_private->stats.cmdau++;
166 		ret = IRQ_HANDLED;
167 	}
168 
169 	if (sisr & CCSR_SSI_SISR_CMDDU) {
170 		ssi_private->stats.cmddu++;
171 		ret = IRQ_HANDLED;
172 	}
173 
174 	if (sisr & CCSR_SSI_SISR_RXT) {
175 		ssi_private->stats.rxt++;
176 		ret = IRQ_HANDLED;
177 	}
178 
179 	if (sisr & CCSR_SSI_SISR_RDR1) {
180 		ssi_private->stats.rdr1++;
181 		ret = IRQ_HANDLED;
182 	}
183 
184 	if (sisr & CCSR_SSI_SISR_RDR0) {
185 		ssi_private->stats.rdr0++;
186 		ret = IRQ_HANDLED;
187 	}
188 
189 	if (sisr & CCSR_SSI_SISR_TDE1) {
190 		ssi_private->stats.tde1++;
191 		ret = IRQ_HANDLED;
192 	}
193 
194 	if (sisr & CCSR_SSI_SISR_TDE0) {
195 		ssi_private->stats.tde0++;
196 		ret = IRQ_HANDLED;
197 	}
198 
199 	if (sisr & CCSR_SSI_SISR_ROE1) {
200 		ssi_private->stats.roe1++;
201 		sisr2 |= CCSR_SSI_SISR_ROE1;
202 		ret = IRQ_HANDLED;
203 	}
204 
205 	if (sisr & CCSR_SSI_SISR_ROE0) {
206 		ssi_private->stats.roe0++;
207 		sisr2 |= CCSR_SSI_SISR_ROE0;
208 		ret = IRQ_HANDLED;
209 	}
210 
211 	if (sisr & CCSR_SSI_SISR_TUE1) {
212 		ssi_private->stats.tue1++;
213 		sisr2 |= CCSR_SSI_SISR_TUE1;
214 		ret = IRQ_HANDLED;
215 	}
216 
217 	if (sisr & CCSR_SSI_SISR_TUE0) {
218 		ssi_private->stats.tue0++;
219 		sisr2 |= CCSR_SSI_SISR_TUE0;
220 		ret = IRQ_HANDLED;
221 	}
222 
223 	if (sisr & CCSR_SSI_SISR_TFS) {
224 		ssi_private->stats.tfs++;
225 		ret = IRQ_HANDLED;
226 	}
227 
228 	if (sisr & CCSR_SSI_SISR_RFS) {
229 		ssi_private->stats.rfs++;
230 		ret = IRQ_HANDLED;
231 	}
232 
233 	if (sisr & CCSR_SSI_SISR_TLS) {
234 		ssi_private->stats.tls++;
235 		ret = IRQ_HANDLED;
236 	}
237 
238 	if (sisr & CCSR_SSI_SISR_RLS) {
239 		ssi_private->stats.rls++;
240 		ret = IRQ_HANDLED;
241 	}
242 
243 	if (sisr & CCSR_SSI_SISR_RFF1) {
244 		ssi_private->stats.rff1++;
245 		ret = IRQ_HANDLED;
246 	}
247 
248 	if (sisr & CCSR_SSI_SISR_RFF0) {
249 		ssi_private->stats.rff0++;
250 		ret = IRQ_HANDLED;
251 	}
252 
253 	if (sisr & CCSR_SSI_SISR_TFE1) {
254 		ssi_private->stats.tfe1++;
255 		ret = IRQ_HANDLED;
256 	}
257 
258 	if (sisr & CCSR_SSI_SISR_TFE0) {
259 		ssi_private->stats.tfe0++;
260 		ret = IRQ_HANDLED;
261 	}
262 
263 	/* Clear the bits that we set */
264 	if (sisr2)
265 		out_be32(&ssi->sisr, sisr2);
266 
267 	return ret;
268 }
269 
270 /**
271  * fsl_ssi_startup: create a new substream
272  *
273  * This is the first function called when a stream is opened.
274  *
275  * If this is the first stream open, then grab the IRQ and program most of
276  * the SSI registers.
277  */
278 static int fsl_ssi_startup(struct snd_pcm_substream *substream,
279 			   struct snd_soc_dai *dai)
280 {
281 	struct snd_soc_pcm_runtime *rtd = substream->private_data;
282 	struct fsl_ssi_private *ssi_private = rtd->dai->cpu_dai->private_data;
283 
284 	/*
285 	 * If this is the first stream opened, then request the IRQ
286 	 * and initialize the SSI registers.
287 	 */
288 	if (!ssi_private->playback && !ssi_private->capture) {
289 		struct ccsr_ssi __iomem *ssi = ssi_private->ssi;
290 		int ret;
291 
292 		ret = request_irq(ssi_private->irq, fsl_ssi_isr, 0,
293 				  ssi_private->name, ssi_private);
294 		if (ret < 0) {
295 			dev_err(substream->pcm->card->dev,
296 				"could not claim irq %u\n", ssi_private->irq);
297 			return ret;
298 		}
299 
300 		/*
301 		 * Section 16.5 of the MPC8610 reference manual says that the
302 		 * SSI needs to be disabled before updating the registers we set
303 		 * here.
304 		 */
305 		clrbits32(&ssi->scr, CCSR_SSI_SCR_SSIEN);
306 
307 		/*
308 		 * Program the SSI into I2S Slave Non-Network Synchronous mode.
309 		 * Also enable the transmit and receive FIFO.
310 		 *
311 		 * FIXME: Little-endian samples require a different shift dir
312 		 */
313 		clrsetbits_be32(&ssi->scr,
314 			CCSR_SSI_SCR_I2S_MODE_MASK | CCSR_SSI_SCR_SYN,
315 			CCSR_SSI_SCR_TFR_CLK_DIS | CCSR_SSI_SCR_I2S_MODE_SLAVE
316 			| (ssi_private->asynchronous ? 0 : CCSR_SSI_SCR_SYN));
317 
318 		out_be32(&ssi->stcr,
319 			 CCSR_SSI_STCR_TXBIT0 | CCSR_SSI_STCR_TFEN0 |
320 			 CCSR_SSI_STCR_TFSI | CCSR_SSI_STCR_TEFS |
321 			 CCSR_SSI_STCR_TSCKP);
322 
323 		out_be32(&ssi->srcr,
324 			 CCSR_SSI_SRCR_RXBIT0 | CCSR_SSI_SRCR_RFEN0 |
325 			 CCSR_SSI_SRCR_RFSI | CCSR_SSI_SRCR_REFS |
326 			 CCSR_SSI_SRCR_RSCKP);
327 
328 		/*
329 		 * The DC and PM bits are only used if the SSI is the clock
330 		 * master.
331 		 */
332 
333 		/* 4. Enable the interrupts and DMA requests */
334 		out_be32(&ssi->sier, SIER_FLAGS);
335 
336 		/*
337 		 * Set the watermark for transmit FIFI 0 and receive FIFO 0. We
338 		 * don't use FIFO 1.  Since the SSI only supports stereo, the
339 		 * watermark should never be an odd number.
340 		 */
341 		out_be32(&ssi->sfcsr,
342 			 CCSR_SSI_SFCSR_TFWM0(6) | CCSR_SSI_SFCSR_RFWM0(2));
343 
344 		/*
345 		 * We keep the SSI disabled because if we enable it, then the
346 		 * DMA controller will start.  It's not supposed to start until
347 		 * the SCR.TE (or SCR.RE) bit is set, but it does anyway.  The
348 		 * DMA controller will transfer one "BWC" of data (i.e. the
349 		 * amount of data that the MR.BWC bits are set to).  The reason
350 		 * this is bad is because at this point, the PCM driver has not
351 		 * finished initializing the DMA controller.
352 		 */
353 	}
354 
355 	if (!ssi_private->first_stream)
356 		ssi_private->first_stream = substream;
357 	else {
358 		/* This is the second stream open, so we need to impose sample
359 		 * rate and maybe sample size constraints.  Note that this can
360 		 * cause a race condition if the second stream is opened before
361 		 * the first stream is fully initialized.
362 		 *
363 		 * We provide some protection by checking to make sure the first
364 		 * stream is initialized, but it's not perfect.  ALSA sometimes
365 		 * re-initializes the driver with a different sample rate or
366 		 * size.  If the second stream is opened before the first stream
367 		 * has received its final parameters, then the second stream may
368 		 * be constrained to the wrong sample rate or size.
369 		 *
370 		 * FIXME: This code does not handle opening and closing streams
371 		 * repeatedly.  If you open two streams and then close the first
372 		 * one, you may not be able to open another stream until you
373 		 * close the second one as well.
374 		 */
375 		struct snd_pcm_runtime *first_runtime =
376 			ssi_private->first_stream->runtime;
377 
378 		if (!first_runtime->sample_bits) {
379 			dev_err(substream->pcm->card->dev,
380 				"set sample size in %s stream first\n",
381 				substream->stream == SNDRV_PCM_STREAM_PLAYBACK
382 				? "capture" : "playback");
383 			return -EAGAIN;
384 		}
385 
386 		/* If we're in synchronous mode, then we need to constrain
387 		 * the sample size as well.  We don't support independent sample
388 		 * rates in asynchronous mode.
389 		 */
390 		if (!ssi_private->asynchronous)
391 			snd_pcm_hw_constraint_minmax(substream->runtime,
392 				SNDRV_PCM_HW_PARAM_SAMPLE_BITS,
393 				first_runtime->sample_bits,
394 				first_runtime->sample_bits);
395 
396 		ssi_private->second_stream = substream;
397 	}
398 
399 	if (substream->stream == SNDRV_PCM_STREAM_PLAYBACK)
400 		ssi_private->playback++;
401 
402 	if (substream->stream == SNDRV_PCM_STREAM_CAPTURE)
403 		ssi_private->capture++;
404 
405 	return 0;
406 }
407 
408 /**
409  * fsl_ssi_hw_params - program the sample size
410  *
411  * Most of the SSI registers have been programmed in the startup function,
412  * but the word length must be programmed here.  Unfortunately, programming
413  * the SxCCR.WL bits requires the SSI to be temporarily disabled.  This can
414  * cause a problem with supporting simultaneous playback and capture.  If
415  * the SSI is already playing a stream, then that stream may be temporarily
416  * stopped when you start capture.
417  *
418  * Note: The SxCCR.DC and SxCCR.PM bits are only used if the SSI is the
419  * clock master.
420  */
421 static int fsl_ssi_hw_params(struct snd_pcm_substream *substream,
422 	struct snd_pcm_hw_params *hw_params, struct snd_soc_dai *cpu_dai)
423 {
424 	struct fsl_ssi_private *ssi_private = cpu_dai->private_data;
425 
426 	if (substream == ssi_private->first_stream) {
427 		struct ccsr_ssi __iomem *ssi = ssi_private->ssi;
428 		unsigned int sample_size =
429 			snd_pcm_format_width(params_format(hw_params));
430 		u32 wl = CCSR_SSI_SxCCR_WL(sample_size);
431 
432 		/* The SSI should always be disabled at this points (SSIEN=0) */
433 
434 		/* In synchronous mode, the SSI uses STCCR for capture */
435 		if ((substream->stream == SNDRV_PCM_STREAM_PLAYBACK) ||
436 		    !ssi_private->asynchronous)
437 			clrsetbits_be32(&ssi->stccr,
438 					CCSR_SSI_SxCCR_WL_MASK, wl);
439 		else
440 			clrsetbits_be32(&ssi->srccr,
441 					CCSR_SSI_SxCCR_WL_MASK, wl);
442 	}
443 
444 	return 0;
445 }
446 
447 /**
448  * fsl_ssi_trigger: start and stop the DMA transfer.
449  *
450  * This function is called by ALSA to start, stop, pause, and resume the DMA
451  * transfer of data.
452  *
453  * The DMA channel is in external master start and pause mode, which
454  * means the SSI completely controls the flow of data.
455  */
456 static int fsl_ssi_trigger(struct snd_pcm_substream *substream, int cmd,
457 			   struct snd_soc_dai *dai)
458 {
459 	struct snd_soc_pcm_runtime *rtd = substream->private_data;
460 	struct fsl_ssi_private *ssi_private = rtd->dai->cpu_dai->private_data;
461 	struct ccsr_ssi __iomem *ssi = ssi_private->ssi;
462 
463 	switch (cmd) {
464 	case SNDRV_PCM_TRIGGER_START:
465 		clrbits32(&ssi->scr, CCSR_SSI_SCR_SSIEN);
466 	case SNDRV_PCM_TRIGGER_PAUSE_RELEASE:
467 		if (substream->stream == SNDRV_PCM_STREAM_PLAYBACK)
468 			setbits32(&ssi->scr,
469 				CCSR_SSI_SCR_SSIEN | CCSR_SSI_SCR_TE);
470 		else
471 			setbits32(&ssi->scr,
472 				CCSR_SSI_SCR_SSIEN | CCSR_SSI_SCR_RE);
473 		break;
474 
475 	case SNDRV_PCM_TRIGGER_STOP:
476 	case SNDRV_PCM_TRIGGER_PAUSE_PUSH:
477 		if (substream->stream == SNDRV_PCM_STREAM_PLAYBACK)
478 			clrbits32(&ssi->scr, CCSR_SSI_SCR_TE);
479 		else
480 			clrbits32(&ssi->scr, CCSR_SSI_SCR_RE);
481 		break;
482 
483 	default:
484 		return -EINVAL;
485 	}
486 
487 	return 0;
488 }
489 
490 /**
491  * fsl_ssi_shutdown: shutdown the SSI
492  *
493  * Shutdown the SSI if there are no other substreams open.
494  */
495 static void fsl_ssi_shutdown(struct snd_pcm_substream *substream,
496 			     struct snd_soc_dai *dai)
497 {
498 	struct snd_soc_pcm_runtime *rtd = substream->private_data;
499 	struct fsl_ssi_private *ssi_private = rtd->dai->cpu_dai->private_data;
500 
501 	if (substream->stream == SNDRV_PCM_STREAM_PLAYBACK)
502 		ssi_private->playback--;
503 
504 	if (substream->stream == SNDRV_PCM_STREAM_CAPTURE)
505 		ssi_private->capture--;
506 
507 	if (ssi_private->first_stream == substream)
508 		ssi_private->first_stream = ssi_private->second_stream;
509 
510 	ssi_private->second_stream = NULL;
511 
512 	/*
513 	 * If this is the last active substream, disable the SSI and release
514 	 * the IRQ.
515 	 */
516 	if (!ssi_private->playback && !ssi_private->capture) {
517 		struct ccsr_ssi __iomem *ssi = ssi_private->ssi;
518 
519 		clrbits32(&ssi->scr, CCSR_SSI_SCR_SSIEN);
520 
521 		free_irq(ssi_private->irq, ssi_private);
522 	}
523 }
524 
525 /**
526  * fsl_ssi_set_sysclk: set the clock frequency and direction
527  *
528  * This function is called by the machine driver to tell us what the clock
529  * frequency and direction are.
530  *
531  * Currently, we only support operating as a clock slave (SND_SOC_CLOCK_IN),
532  * and we don't care about the frequency.  Return an error if the direction
533  * is not SND_SOC_CLOCK_IN.
534  *
535  * @clk_id: reserved, should be zero
536  * @freq: the frequency of the given clock ID, currently ignored
537  * @dir: SND_SOC_CLOCK_IN (clock slave) or SND_SOC_CLOCK_OUT (clock master)
538  */
539 static int fsl_ssi_set_sysclk(struct snd_soc_dai *cpu_dai,
540 			      int clk_id, unsigned int freq, int dir)
541 {
542 
543 	return (dir == SND_SOC_CLOCK_IN) ? 0 : -EINVAL;
544 }
545 
546 /**
547  * fsl_ssi_set_fmt: set the serial format.
548  *
549  * This function is called by the machine driver to tell us what serial
550  * format to use.
551  *
552  * Currently, we only support I2S mode.  Return an error if the format is
553  * not SND_SOC_DAIFMT_I2S.
554  *
555  * @format: one of SND_SOC_DAIFMT_xxx
556  */
557 static int fsl_ssi_set_fmt(struct snd_soc_dai *cpu_dai, unsigned int format)
558 {
559 	return (format == SND_SOC_DAIFMT_I2S) ? 0 : -EINVAL;
560 }
561 
562 /**
563  * fsl_ssi_dai_template: template CPU DAI for the SSI
564  */
565 static struct snd_soc_dai_ops fsl_ssi_dai_ops = {
566 	.startup	= fsl_ssi_startup,
567 	.hw_params	= fsl_ssi_hw_params,
568 	.shutdown	= fsl_ssi_shutdown,
569 	.trigger	= fsl_ssi_trigger,
570 	.set_sysclk	= fsl_ssi_set_sysclk,
571 	.set_fmt	= fsl_ssi_set_fmt,
572 };
573 
574 static struct snd_soc_dai fsl_ssi_dai_template = {
575 	.playback = {
576 		/* The SSI does not support monaural audio. */
577 		.channels_min = 2,
578 		.channels_max = 2,
579 		.rates = FSLSSI_I2S_RATES,
580 		.formats = FSLSSI_I2S_FORMATS,
581 	},
582 	.capture = {
583 		.channels_min = 2,
584 		.channels_max = 2,
585 		.rates = FSLSSI_I2S_RATES,
586 		.formats = FSLSSI_I2S_FORMATS,
587 	},
588 	.ops = &fsl_ssi_dai_ops,
589 };
590 
591 /* Show the statistics of a flag only if its interrupt is enabled.  The
592  * compiler will optimze this code to a no-op if the interrupt is not
593  * enabled.
594  */
595 #define SIER_SHOW(flag, name) \
596 	do { \
597 		if (SIER_FLAGS & CCSR_SSI_SIER_##flag) \
598 			length += sprintf(buf + length, #name "=%u\n", \
599 				ssi_private->stats.name); \
600 	} while (0)
601 
602 
603 /**
604  * fsl_sysfs_ssi_show: display SSI statistics
605  *
606  * Display the statistics for the current SSI device.  To avoid confusion,
607  * we only show those counts that are enabled.
608  */
609 static ssize_t fsl_sysfs_ssi_show(struct device *dev,
610 	struct device_attribute *attr, char *buf)
611 {
612 	struct fsl_ssi_private *ssi_private =
613 		container_of(attr, struct fsl_ssi_private, dev_attr);
614 	ssize_t length = 0;
615 
616 	SIER_SHOW(RFRC_EN, rfrc);
617 	SIER_SHOW(TFRC_EN, tfrc);
618 	SIER_SHOW(CMDAU_EN, cmdau);
619 	SIER_SHOW(CMDDU_EN, cmddu);
620 	SIER_SHOW(RXT_EN, rxt);
621 	SIER_SHOW(RDR1_EN, rdr1);
622 	SIER_SHOW(RDR0_EN, rdr0);
623 	SIER_SHOW(TDE1_EN, tde1);
624 	SIER_SHOW(TDE0_EN, tde0);
625 	SIER_SHOW(ROE1_EN, roe1);
626 	SIER_SHOW(ROE0_EN, roe0);
627 	SIER_SHOW(TUE1_EN, tue1);
628 	SIER_SHOW(TUE0_EN, tue0);
629 	SIER_SHOW(TFS_EN, tfs);
630 	SIER_SHOW(RFS_EN, rfs);
631 	SIER_SHOW(TLS_EN, tls);
632 	SIER_SHOW(RLS_EN, rls);
633 	SIER_SHOW(RFF1_EN, rff1);
634 	SIER_SHOW(RFF0_EN, rff0);
635 	SIER_SHOW(TFE1_EN, tfe1);
636 	SIER_SHOW(TFE0_EN, tfe0);
637 
638 	return length;
639 }
640 
641 /**
642  * fsl_ssi_create_dai: create a snd_soc_dai structure
643  *
644  * This function is called by the machine driver to create a snd_soc_dai
645  * structure.  The function creates an ssi_private object, which contains
646  * the snd_soc_dai.  It also creates the sysfs statistics device.
647  */
648 struct snd_soc_dai *fsl_ssi_create_dai(struct fsl_ssi_info *ssi_info)
649 {
650 	struct snd_soc_dai *fsl_ssi_dai;
651 	struct fsl_ssi_private *ssi_private;
652 	int ret = 0;
653 	struct device_attribute *dev_attr;
654 
655 	ssi_private = kzalloc(sizeof(struct fsl_ssi_private), GFP_KERNEL);
656 	if (!ssi_private) {
657 		dev_err(ssi_info->dev, "could not allocate DAI object\n");
658 		return NULL;
659 	}
660 	memcpy(&ssi_private->cpu_dai, &fsl_ssi_dai_template,
661 	       sizeof(struct snd_soc_dai));
662 
663 	fsl_ssi_dai = &ssi_private->cpu_dai;
664 	dev_attr = &ssi_private->dev_attr;
665 
666 	sprintf(ssi_private->name, "ssi%u", (u8) ssi_info->id);
667 	ssi_private->ssi = ssi_info->ssi;
668 	ssi_private->ssi_phys = ssi_info->ssi_phys;
669 	ssi_private->irq = ssi_info->irq;
670 	ssi_private->dev = ssi_info->dev;
671 	ssi_private->asynchronous = ssi_info->asynchronous;
672 
673 	dev_set_drvdata(ssi_private->dev, fsl_ssi_dai);
674 
675 	/* Initialize the the device_attribute structure */
676 	dev_attr->attr.name = "ssi-stats";
677 	dev_attr->attr.mode = S_IRUGO;
678 	dev_attr->show = fsl_sysfs_ssi_show;
679 
680 	ret = device_create_file(ssi_private->dev, dev_attr);
681 	if (ret) {
682 		dev_err(ssi_info->dev, "could not create sysfs %s file\n",
683 			ssi_private->dev_attr.attr.name);
684 		kfree(fsl_ssi_dai);
685 		return NULL;
686 	}
687 
688 	fsl_ssi_dai->private_data = ssi_private;
689 	fsl_ssi_dai->name = ssi_private->name;
690 	fsl_ssi_dai->id = ssi_info->id;
691 	fsl_ssi_dai->dev = ssi_info->dev;
692 	fsl_ssi_dai->symmetric_rates = 1;
693 
694 	ret = snd_soc_register_dai(fsl_ssi_dai);
695 	if (ret != 0) {
696 		dev_err(ssi_info->dev, "failed to register DAI: %d\n", ret);
697 		kfree(fsl_ssi_dai);
698 		return NULL;
699 	}
700 
701 	return fsl_ssi_dai;
702 }
703 EXPORT_SYMBOL_GPL(fsl_ssi_create_dai);
704 
705 /**
706  * fsl_ssi_destroy_dai: destroy the snd_soc_dai object
707  *
708  * This function undoes the operations of fsl_ssi_create_dai()
709  */
710 void fsl_ssi_destroy_dai(struct snd_soc_dai *fsl_ssi_dai)
711 {
712 	struct fsl_ssi_private *ssi_private =
713 	container_of(fsl_ssi_dai, struct fsl_ssi_private, cpu_dai);
714 
715 	device_remove_file(ssi_private->dev, &ssi_private->dev_attr);
716 
717 	snd_soc_unregister_dai(&ssi_private->cpu_dai);
718 
719 	kfree(ssi_private);
720 }
721 EXPORT_SYMBOL_GPL(fsl_ssi_destroy_dai);
722 
723 static int __init fsl_ssi_init(void)
724 {
725 	printk(KERN_INFO "Freescale Synchronous Serial Interface (SSI) ASoC Driver\n");
726 
727 	return 0;
728 }
729 module_init(fsl_ssi_init);
730 
731 MODULE_AUTHOR("Timur Tabi <timur@freescale.com>");
732 MODULE_DESCRIPTION("Freescale Synchronous Serial Interface (SSI) ASoC Driver");
733 MODULE_LICENSE("GPL");
734