xref: /openbmc/linux/sound/drivers/dummy.c (revision f42b3800)
1 /*
2  *  Dummy soundcard
3  *  Copyright (c) by Jaroslav Kysela <perex@perex.cz>
4  *
5  *   This program is free software; you can redistribute it and/or modify
6  *   it under the terms of the GNU General Public License as published by
7  *   the Free Software Foundation; either version 2 of the License, or
8  *   (at your option) any later version.
9  *
10  *   This program is distributed in the hope that it will be useful,
11  *   but WITHOUT ANY WARRANTY; without even the implied warranty of
12  *   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
13  *   GNU General Public License for more details.
14  *
15  *   You should have received a copy of the GNU General Public License
16  *   along with this program; if not, write to the Free Software
17  *   Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307 USA
18  *
19  */
20 
21 #include <linux/init.h>
22 #include <linux/err.h>
23 #include <linux/platform_device.h>
24 #include <linux/jiffies.h>
25 #include <linux/slab.h>
26 #include <linux/time.h>
27 #include <linux/wait.h>
28 #include <linux/moduleparam.h>
29 #include <sound/core.h>
30 #include <sound/control.h>
31 #include <sound/tlv.h>
32 #include <sound/pcm.h>
33 #include <sound/rawmidi.h>
34 #include <sound/initval.h>
35 
36 MODULE_AUTHOR("Jaroslav Kysela <perex@perex.cz>");
37 MODULE_DESCRIPTION("Dummy soundcard (/dev/null)");
38 MODULE_LICENSE("GPL");
39 MODULE_SUPPORTED_DEVICE("{{ALSA,Dummy soundcard}}");
40 
41 #define MAX_PCM_DEVICES		4
42 #define MAX_PCM_SUBSTREAMS	16
43 #define MAX_MIDI_DEVICES	2
44 
45 #if 0 /* emu10k1 emulation */
46 #define MAX_BUFFER_SIZE		(128 * 1024)
47 static int emu10k1_playback_constraints(struct snd_pcm_runtime *runtime)
48 {
49 	int err;
50 	if ((err = snd_pcm_hw_constraint_integer(runtime, SNDRV_PCM_HW_PARAM_PERIODS)) < 0)
51 		return err;
52 	if ((err = snd_pcm_hw_constraint_minmax(runtime, SNDRV_PCM_HW_PARAM_BUFFER_BYTES, 256, UINT_MAX)) < 0)
53 		return err;
54 	return 0;
55 }
56 #define add_playback_constraints emu10k1_playback_constraints
57 #endif
58 
59 #if 0 /* RME9652 emulation */
60 #define MAX_BUFFER_SIZE		(26 * 64 * 1024)
61 #define USE_FORMATS		SNDRV_PCM_FMTBIT_S32_LE
62 #define USE_CHANNELS_MIN	26
63 #define USE_CHANNELS_MAX	26
64 #define USE_PERIODS_MIN		2
65 #define USE_PERIODS_MAX		2
66 #endif
67 
68 #if 0 /* ICE1712 emulation */
69 #define MAX_BUFFER_SIZE		(256 * 1024)
70 #define USE_FORMATS		SNDRV_PCM_FMTBIT_S32_LE
71 #define USE_CHANNELS_MIN	10
72 #define USE_CHANNELS_MAX	10
73 #define USE_PERIODS_MIN		1
74 #define USE_PERIODS_MAX		1024
75 #endif
76 
77 #if 0 /* UDA1341 emulation */
78 #define MAX_BUFFER_SIZE		(16380)
79 #define USE_FORMATS		SNDRV_PCM_FMTBIT_S16_LE
80 #define USE_CHANNELS_MIN	2
81 #define USE_CHANNELS_MAX	2
82 #define USE_PERIODS_MIN		2
83 #define USE_PERIODS_MAX		255
84 #endif
85 
86 #if 0 /* simple AC97 bridge (intel8x0) with 48kHz AC97 only codec */
87 #define USE_FORMATS		SNDRV_PCM_FMTBIT_S16_LE
88 #define USE_CHANNELS_MIN	2
89 #define USE_CHANNELS_MAX	2
90 #define USE_RATE		SNDRV_PCM_RATE_48000
91 #define USE_RATE_MIN		48000
92 #define USE_RATE_MAX		48000
93 #endif
94 
95 #if 0 /* CA0106 */
96 #define USE_FORMATS		SNDRV_PCM_FMTBIT_S16_LE
97 #define USE_CHANNELS_MIN	2
98 #define USE_CHANNELS_MAX	2
99 #define USE_RATE		(SNDRV_PCM_RATE_48000|SNDRV_PCM_RATE_96000|SNDRV_PCM_RATE_192000)
100 #define USE_RATE_MIN		48000
101 #define USE_RATE_MAX		192000
102 #define MAX_BUFFER_SIZE		((65536-64)*8)
103 #define MAX_PERIOD_SIZE		(65536-64)
104 #define USE_PERIODS_MIN		2
105 #define USE_PERIODS_MAX		8
106 #endif
107 
108 
109 /* defaults */
110 #ifndef MAX_BUFFER_SIZE
111 #define MAX_BUFFER_SIZE		(64*1024)
112 #endif
113 #ifndef MAX_PERIOD_SIZE
114 #define MAX_PERIOD_SIZE		MAX_BUFFER_SIZE
115 #endif
116 #ifndef USE_FORMATS
117 #define USE_FORMATS 		(SNDRV_PCM_FMTBIT_U8 | SNDRV_PCM_FMTBIT_S16_LE)
118 #endif
119 #ifndef USE_RATE
120 #define USE_RATE		SNDRV_PCM_RATE_CONTINUOUS | SNDRV_PCM_RATE_8000_48000
121 #define USE_RATE_MIN		5500
122 #define USE_RATE_MAX		48000
123 #endif
124 #ifndef USE_CHANNELS_MIN
125 #define USE_CHANNELS_MIN 	1
126 #endif
127 #ifndef USE_CHANNELS_MAX
128 #define USE_CHANNELS_MAX 	2
129 #endif
130 #ifndef USE_PERIODS_MIN
131 #define USE_PERIODS_MIN 	1
132 #endif
133 #ifndef USE_PERIODS_MAX
134 #define USE_PERIODS_MAX 	1024
135 #endif
136 #ifndef add_playback_constraints
137 #define add_playback_constraints(x) 0
138 #endif
139 #ifndef add_capture_constraints
140 #define add_capture_constraints(x) 0
141 #endif
142 
143 static int index[SNDRV_CARDS] = SNDRV_DEFAULT_IDX;	/* Index 0-MAX */
144 static char *id[SNDRV_CARDS] = SNDRV_DEFAULT_STR;	/* ID for this card */
145 static int enable[SNDRV_CARDS] = {1, [1 ... (SNDRV_CARDS - 1)] = 0};
146 static int pcm_devs[SNDRV_CARDS] = {[0 ... (SNDRV_CARDS - 1)] = 1};
147 static int pcm_substreams[SNDRV_CARDS] = {[0 ... (SNDRV_CARDS - 1)] = 8};
148 //static int midi_devs[SNDRV_CARDS] = {[0 ... (SNDRV_CARDS - 1)] = 2};
149 
150 module_param_array(index, int, NULL, 0444);
151 MODULE_PARM_DESC(index, "Index value for dummy soundcard.");
152 module_param_array(id, charp, NULL, 0444);
153 MODULE_PARM_DESC(id, "ID string for dummy soundcard.");
154 module_param_array(enable, bool, NULL, 0444);
155 MODULE_PARM_DESC(enable, "Enable this dummy soundcard.");
156 module_param_array(pcm_devs, int, NULL, 0444);
157 MODULE_PARM_DESC(pcm_devs, "PCM devices # (0-4) for dummy driver.");
158 module_param_array(pcm_substreams, int, NULL, 0444);
159 MODULE_PARM_DESC(pcm_substreams, "PCM substreams # (1-16) for dummy driver.");
160 //module_param_array(midi_devs, int, NULL, 0444);
161 //MODULE_PARM_DESC(midi_devs, "MIDI devices # (0-2) for dummy driver.");
162 
163 static struct platform_device *devices[SNDRV_CARDS];
164 
165 #define MIXER_ADDR_MASTER	0
166 #define MIXER_ADDR_LINE		1
167 #define MIXER_ADDR_MIC		2
168 #define MIXER_ADDR_SYNTH	3
169 #define MIXER_ADDR_CD		4
170 #define MIXER_ADDR_LAST		4
171 
172 struct snd_dummy {
173 	struct snd_card *card;
174 	struct snd_pcm *pcm;
175 	spinlock_t mixer_lock;
176 	int mixer_volume[MIXER_ADDR_LAST+1][2];
177 	int capture_source[MIXER_ADDR_LAST+1][2];
178 };
179 
180 struct snd_dummy_pcm {
181 	struct snd_dummy *dummy;
182 	spinlock_t lock;
183 	struct timer_list timer;
184 	unsigned int pcm_size;
185 	unsigned int pcm_count;
186 	unsigned int pcm_bps;		/* bytes per second */
187 	unsigned int pcm_jiffie;	/* bytes per one jiffie */
188 	unsigned int pcm_irq_pos;	/* IRQ position */
189 	unsigned int pcm_buf_pos;	/* position in buffer */
190 	struct snd_pcm_substream *substream;
191 };
192 
193 
194 static inline void snd_card_dummy_pcm_timer_start(struct snd_dummy_pcm *dpcm)
195 {
196 	dpcm->timer.expires = 1 + jiffies;
197 	add_timer(&dpcm->timer);
198 }
199 
200 static inline void snd_card_dummy_pcm_timer_stop(struct snd_dummy_pcm *dpcm)
201 {
202 	del_timer(&dpcm->timer);
203 }
204 
205 static int snd_card_dummy_pcm_trigger(struct snd_pcm_substream *substream, int cmd)
206 {
207 	struct snd_pcm_runtime *runtime = substream->runtime;
208 	struct snd_dummy_pcm *dpcm = runtime->private_data;
209 	int err = 0;
210 
211 	spin_lock(&dpcm->lock);
212 	switch (cmd) {
213 	case SNDRV_PCM_TRIGGER_START:
214 	case SNDRV_PCM_TRIGGER_RESUME:
215 		snd_card_dummy_pcm_timer_start(dpcm);
216 		break;
217 	case SNDRV_PCM_TRIGGER_STOP:
218 	case SNDRV_PCM_TRIGGER_SUSPEND:
219 		snd_card_dummy_pcm_timer_stop(dpcm);
220 		break;
221 	default:
222 		err = -EINVAL;
223 		break;
224 	}
225 	spin_unlock(&dpcm->lock);
226 	return 0;
227 }
228 
229 static int snd_card_dummy_pcm_prepare(struct snd_pcm_substream *substream)
230 {
231 	struct snd_pcm_runtime *runtime = substream->runtime;
232 	struct snd_dummy_pcm *dpcm = runtime->private_data;
233 	unsigned int bps;
234 
235 	bps = runtime->rate * runtime->channels;
236 	bps *= snd_pcm_format_width(runtime->format);
237 	bps /= 8;
238 	if (bps <= 0)
239 		return -EINVAL;
240 	dpcm->pcm_bps = bps;
241 	dpcm->pcm_jiffie = bps / HZ;
242 	dpcm->pcm_size = snd_pcm_lib_buffer_bytes(substream);
243 	dpcm->pcm_count = snd_pcm_lib_period_bytes(substream);
244 	dpcm->pcm_irq_pos = 0;
245 	dpcm->pcm_buf_pos = 0;
246 	return 0;
247 }
248 
249 static void snd_card_dummy_pcm_timer_function(unsigned long data)
250 {
251 	struct snd_dummy_pcm *dpcm = (struct snd_dummy_pcm *)data;
252 	unsigned long flags;
253 
254 	spin_lock_irqsave(&dpcm->lock, flags);
255 	dpcm->timer.expires = 1 + jiffies;
256 	add_timer(&dpcm->timer);
257 	dpcm->pcm_irq_pos += dpcm->pcm_jiffie;
258 	dpcm->pcm_buf_pos += dpcm->pcm_jiffie;
259 	dpcm->pcm_buf_pos %= dpcm->pcm_size;
260 	if (dpcm->pcm_irq_pos >= dpcm->pcm_count) {
261 		dpcm->pcm_irq_pos %= dpcm->pcm_count;
262 		spin_unlock_irqrestore(&dpcm->lock, flags);
263 		snd_pcm_period_elapsed(dpcm->substream);
264 	} else
265 		spin_unlock_irqrestore(&dpcm->lock, flags);
266 }
267 
268 static snd_pcm_uframes_t snd_card_dummy_pcm_pointer(struct snd_pcm_substream *substream)
269 {
270 	struct snd_pcm_runtime *runtime = substream->runtime;
271 	struct snd_dummy_pcm *dpcm = runtime->private_data;
272 
273 	return bytes_to_frames(runtime, dpcm->pcm_buf_pos);
274 }
275 
276 static struct snd_pcm_hardware snd_card_dummy_playback =
277 {
278 	.info =			(SNDRV_PCM_INFO_MMAP | SNDRV_PCM_INFO_INTERLEAVED |
279 				 SNDRV_PCM_INFO_RESUME | SNDRV_PCM_INFO_MMAP_VALID),
280 	.formats =		USE_FORMATS,
281 	.rates =		USE_RATE,
282 	.rate_min =		USE_RATE_MIN,
283 	.rate_max =		USE_RATE_MAX,
284 	.channels_min =		USE_CHANNELS_MIN,
285 	.channels_max =		USE_CHANNELS_MAX,
286 	.buffer_bytes_max =	MAX_BUFFER_SIZE,
287 	.period_bytes_min =	64,
288 	.period_bytes_max =	MAX_PERIOD_SIZE,
289 	.periods_min =		USE_PERIODS_MIN,
290 	.periods_max =		USE_PERIODS_MAX,
291 	.fifo_size =		0,
292 };
293 
294 static struct snd_pcm_hardware snd_card_dummy_capture =
295 {
296 	.info =			(SNDRV_PCM_INFO_MMAP | SNDRV_PCM_INFO_INTERLEAVED |
297 				 SNDRV_PCM_INFO_RESUME | SNDRV_PCM_INFO_MMAP_VALID),
298 	.formats =		USE_FORMATS,
299 	.rates =		USE_RATE,
300 	.rate_min =		USE_RATE_MIN,
301 	.rate_max =		USE_RATE_MAX,
302 	.channels_min =		USE_CHANNELS_MIN,
303 	.channels_max =		USE_CHANNELS_MAX,
304 	.buffer_bytes_max =	MAX_BUFFER_SIZE,
305 	.period_bytes_min =	64,
306 	.period_bytes_max =	MAX_PERIOD_SIZE,
307 	.periods_min =		USE_PERIODS_MIN,
308 	.periods_max =		USE_PERIODS_MAX,
309 	.fifo_size =		0,
310 };
311 
312 static void snd_card_dummy_runtime_free(struct snd_pcm_runtime *runtime)
313 {
314 	kfree(runtime->private_data);
315 }
316 
317 static int snd_card_dummy_hw_params(struct snd_pcm_substream *substream,
318 				    struct snd_pcm_hw_params *hw_params)
319 {
320 	return snd_pcm_lib_malloc_pages(substream, params_buffer_bytes(hw_params));
321 }
322 
323 static int snd_card_dummy_hw_free(struct snd_pcm_substream *substream)
324 {
325 	return snd_pcm_lib_free_pages(substream);
326 }
327 
328 static struct snd_dummy_pcm *new_pcm_stream(struct snd_pcm_substream *substream)
329 {
330 	struct snd_dummy_pcm *dpcm;
331 
332 	dpcm = kzalloc(sizeof(*dpcm), GFP_KERNEL);
333 	if (! dpcm)
334 		return dpcm;
335 	init_timer(&dpcm->timer);
336 	dpcm->timer.data = (unsigned long) dpcm;
337 	dpcm->timer.function = snd_card_dummy_pcm_timer_function;
338 	spin_lock_init(&dpcm->lock);
339 	dpcm->substream = substream;
340 	return dpcm;
341 }
342 
343 static int snd_card_dummy_playback_open(struct snd_pcm_substream *substream)
344 {
345 	struct snd_pcm_runtime *runtime = substream->runtime;
346 	struct snd_dummy_pcm *dpcm;
347 	int err;
348 
349 	if ((dpcm = new_pcm_stream(substream)) == NULL)
350 		return -ENOMEM;
351 	runtime->private_data = dpcm;
352 	runtime->private_free = snd_card_dummy_runtime_free;
353 	runtime->hw = snd_card_dummy_playback;
354 	if (substream->pcm->device & 1) {
355 		runtime->hw.info &= ~SNDRV_PCM_INFO_INTERLEAVED;
356 		runtime->hw.info |= SNDRV_PCM_INFO_NONINTERLEAVED;
357 	}
358 	if (substream->pcm->device & 2)
359 		runtime->hw.info &= ~(SNDRV_PCM_INFO_MMAP|SNDRV_PCM_INFO_MMAP_VALID);
360 	if ((err = add_playback_constraints(runtime)) < 0) {
361 		kfree(dpcm);
362 		return err;
363 	}
364 
365 	return 0;
366 }
367 
368 static int snd_card_dummy_capture_open(struct snd_pcm_substream *substream)
369 {
370 	struct snd_pcm_runtime *runtime = substream->runtime;
371 	struct snd_dummy_pcm *dpcm;
372 	int err;
373 
374 	if ((dpcm = new_pcm_stream(substream)) == NULL)
375 		return -ENOMEM;
376 	runtime->private_data = dpcm;
377 	runtime->private_free = snd_card_dummy_runtime_free;
378 	runtime->hw = snd_card_dummy_capture;
379 	if (substream->pcm->device == 1) {
380 		runtime->hw.info &= ~SNDRV_PCM_INFO_INTERLEAVED;
381 		runtime->hw.info |= SNDRV_PCM_INFO_NONINTERLEAVED;
382 	}
383 	if (substream->pcm->device & 2)
384 		runtime->hw.info &= ~(SNDRV_PCM_INFO_MMAP|SNDRV_PCM_INFO_MMAP_VALID);
385 	if ((err = add_capture_constraints(runtime)) < 0) {
386 		kfree(dpcm);
387 		return err;
388 	}
389 
390 	return 0;
391 }
392 
393 static int snd_card_dummy_playback_close(struct snd_pcm_substream *substream)
394 {
395 	return 0;
396 }
397 
398 static int snd_card_dummy_capture_close(struct snd_pcm_substream *substream)
399 {
400 	return 0;
401 }
402 
403 static struct snd_pcm_ops snd_card_dummy_playback_ops = {
404 	.open =			snd_card_dummy_playback_open,
405 	.close =		snd_card_dummy_playback_close,
406 	.ioctl =		snd_pcm_lib_ioctl,
407 	.hw_params =		snd_card_dummy_hw_params,
408 	.hw_free =		snd_card_dummy_hw_free,
409 	.prepare =		snd_card_dummy_pcm_prepare,
410 	.trigger =		snd_card_dummy_pcm_trigger,
411 	.pointer =		snd_card_dummy_pcm_pointer,
412 };
413 
414 static struct snd_pcm_ops snd_card_dummy_capture_ops = {
415 	.open =			snd_card_dummy_capture_open,
416 	.close =		snd_card_dummy_capture_close,
417 	.ioctl =		snd_pcm_lib_ioctl,
418 	.hw_params =		snd_card_dummy_hw_params,
419 	.hw_free =		snd_card_dummy_hw_free,
420 	.prepare =		snd_card_dummy_pcm_prepare,
421 	.trigger =		snd_card_dummy_pcm_trigger,
422 	.pointer =		snd_card_dummy_pcm_pointer,
423 };
424 
425 static int __devinit snd_card_dummy_pcm(struct snd_dummy *dummy, int device,
426 					int substreams)
427 {
428 	struct snd_pcm *pcm;
429 	int err;
430 
431 	if ((err = snd_pcm_new(dummy->card, "Dummy PCM", device,
432 			       substreams, substreams, &pcm)) < 0)
433 		return err;
434 	dummy->pcm = pcm;
435 	snd_pcm_set_ops(pcm, SNDRV_PCM_STREAM_PLAYBACK, &snd_card_dummy_playback_ops);
436 	snd_pcm_set_ops(pcm, SNDRV_PCM_STREAM_CAPTURE, &snd_card_dummy_capture_ops);
437 	pcm->private_data = dummy;
438 	pcm->info_flags = 0;
439 	strcpy(pcm->name, "Dummy PCM");
440 	snd_pcm_lib_preallocate_pages_for_all(pcm, SNDRV_DMA_TYPE_CONTINUOUS,
441 					      snd_dma_continuous_data(GFP_KERNEL),
442 					      0, 64*1024);
443 	return 0;
444 }
445 
446 #define DUMMY_VOLUME(xname, xindex, addr) \
447 { .iface = SNDRV_CTL_ELEM_IFACE_MIXER, \
448   .access = SNDRV_CTL_ELEM_ACCESS_READWRITE | SNDRV_CTL_ELEM_ACCESS_TLV_READ, \
449   .name = xname, .index = xindex, \
450   .info = snd_dummy_volume_info, \
451   .get = snd_dummy_volume_get, .put = snd_dummy_volume_put, \
452   .private_value = addr, \
453   .tlv = { .p = db_scale_dummy } }
454 
455 static int snd_dummy_volume_info(struct snd_kcontrol *kcontrol,
456 				 struct snd_ctl_elem_info *uinfo)
457 {
458 	uinfo->type = SNDRV_CTL_ELEM_TYPE_INTEGER;
459 	uinfo->count = 2;
460 	uinfo->value.integer.min = -50;
461 	uinfo->value.integer.max = 100;
462 	return 0;
463 }
464 
465 static int snd_dummy_volume_get(struct snd_kcontrol *kcontrol,
466 				struct snd_ctl_elem_value *ucontrol)
467 {
468 	struct snd_dummy *dummy = snd_kcontrol_chip(kcontrol);
469 	int addr = kcontrol->private_value;
470 
471 	spin_lock_irq(&dummy->mixer_lock);
472 	ucontrol->value.integer.value[0] = dummy->mixer_volume[addr][0];
473 	ucontrol->value.integer.value[1] = dummy->mixer_volume[addr][1];
474 	spin_unlock_irq(&dummy->mixer_lock);
475 	return 0;
476 }
477 
478 static int snd_dummy_volume_put(struct snd_kcontrol *kcontrol,
479 				struct snd_ctl_elem_value *ucontrol)
480 {
481 	struct snd_dummy *dummy = snd_kcontrol_chip(kcontrol);
482 	int change, addr = kcontrol->private_value;
483 	int left, right;
484 
485 	left = ucontrol->value.integer.value[0];
486 	if (left < -50)
487 		left = -50;
488 	if (left > 100)
489 		left = 100;
490 	right = ucontrol->value.integer.value[1];
491 	if (right < -50)
492 		right = -50;
493 	if (right > 100)
494 		right = 100;
495 	spin_lock_irq(&dummy->mixer_lock);
496 	change = dummy->mixer_volume[addr][0] != left ||
497 	         dummy->mixer_volume[addr][1] != right;
498 	dummy->mixer_volume[addr][0] = left;
499 	dummy->mixer_volume[addr][1] = right;
500 	spin_unlock_irq(&dummy->mixer_lock);
501 	return change;
502 }
503 
504 static const DECLARE_TLV_DB_SCALE(db_scale_dummy, -4500, 30, 0);
505 
506 #define DUMMY_CAPSRC(xname, xindex, addr) \
507 { .iface = SNDRV_CTL_ELEM_IFACE_MIXER, .name = xname, .index = xindex, \
508   .info = snd_dummy_capsrc_info, \
509   .get = snd_dummy_capsrc_get, .put = snd_dummy_capsrc_put, \
510   .private_value = addr }
511 
512 #define snd_dummy_capsrc_info	snd_ctl_boolean_stereo_info
513 
514 static int snd_dummy_capsrc_get(struct snd_kcontrol *kcontrol,
515 				struct snd_ctl_elem_value *ucontrol)
516 {
517 	struct snd_dummy *dummy = snd_kcontrol_chip(kcontrol);
518 	int addr = kcontrol->private_value;
519 
520 	spin_lock_irq(&dummy->mixer_lock);
521 	ucontrol->value.integer.value[0] = dummy->capture_source[addr][0];
522 	ucontrol->value.integer.value[1] = dummy->capture_source[addr][1];
523 	spin_unlock_irq(&dummy->mixer_lock);
524 	return 0;
525 }
526 
527 static int snd_dummy_capsrc_put(struct snd_kcontrol *kcontrol, struct snd_ctl_elem_value *ucontrol)
528 {
529 	struct snd_dummy *dummy = snd_kcontrol_chip(kcontrol);
530 	int change, addr = kcontrol->private_value;
531 	int left, right;
532 
533 	left = ucontrol->value.integer.value[0] & 1;
534 	right = ucontrol->value.integer.value[1] & 1;
535 	spin_lock_irq(&dummy->mixer_lock);
536 	change = dummy->capture_source[addr][0] != left &&
537 	         dummy->capture_source[addr][1] != right;
538 	dummy->capture_source[addr][0] = left;
539 	dummy->capture_source[addr][1] = right;
540 	spin_unlock_irq(&dummy->mixer_lock);
541 	return change;
542 }
543 
544 static struct snd_kcontrol_new snd_dummy_controls[] = {
545 DUMMY_VOLUME("Master Volume", 0, MIXER_ADDR_MASTER),
546 DUMMY_CAPSRC("Master Capture Switch", 0, MIXER_ADDR_MASTER),
547 DUMMY_VOLUME("Synth Volume", 0, MIXER_ADDR_SYNTH),
548 DUMMY_CAPSRC("Synth Capture Switch", 0, MIXER_ADDR_SYNTH),
549 DUMMY_VOLUME("Line Volume", 0, MIXER_ADDR_LINE),
550 DUMMY_CAPSRC("Line Capture Switch", 0, MIXER_ADDR_LINE),
551 DUMMY_VOLUME("Mic Volume", 0, MIXER_ADDR_MIC),
552 DUMMY_CAPSRC("Mic Capture Switch", 0, MIXER_ADDR_MIC),
553 DUMMY_VOLUME("CD Volume", 0, MIXER_ADDR_CD),
554 DUMMY_CAPSRC("CD Capture Switch", 0, MIXER_ADDR_CD)
555 };
556 
557 static int __devinit snd_card_dummy_new_mixer(struct snd_dummy *dummy)
558 {
559 	struct snd_card *card = dummy->card;
560 	unsigned int idx;
561 	int err;
562 
563 	snd_assert(dummy != NULL, return -EINVAL);
564 	spin_lock_init(&dummy->mixer_lock);
565 	strcpy(card->mixername, "Dummy Mixer");
566 
567 	for (idx = 0; idx < ARRAY_SIZE(snd_dummy_controls); idx++) {
568 		if ((err = snd_ctl_add(card, snd_ctl_new1(&snd_dummy_controls[idx], dummy))) < 0)
569 			return err;
570 	}
571 	return 0;
572 }
573 
574 static int __devinit snd_dummy_probe(struct platform_device *devptr)
575 {
576 	struct snd_card *card;
577 	struct snd_dummy *dummy;
578 	int idx, err;
579 	int dev = devptr->id;
580 
581 	card = snd_card_new(index[dev], id[dev], THIS_MODULE,
582 			    sizeof(struct snd_dummy));
583 	if (card == NULL)
584 		return -ENOMEM;
585 	dummy = card->private_data;
586 	dummy->card = card;
587 	for (idx = 0; idx < MAX_PCM_DEVICES && idx < pcm_devs[dev]; idx++) {
588 		if (pcm_substreams[dev] < 1)
589 			pcm_substreams[dev] = 1;
590 		if (pcm_substreams[dev] > MAX_PCM_SUBSTREAMS)
591 			pcm_substreams[dev] = MAX_PCM_SUBSTREAMS;
592 		if ((err = snd_card_dummy_pcm(dummy, idx, pcm_substreams[dev])) < 0)
593 			goto __nodev;
594 	}
595 	if ((err = snd_card_dummy_new_mixer(dummy)) < 0)
596 		goto __nodev;
597 	strcpy(card->driver, "Dummy");
598 	strcpy(card->shortname, "Dummy");
599 	sprintf(card->longname, "Dummy %i", dev + 1);
600 
601 	snd_card_set_dev(card, &devptr->dev);
602 
603 	if ((err = snd_card_register(card)) == 0) {
604 		platform_set_drvdata(devptr, card);
605 		return 0;
606 	}
607       __nodev:
608 	snd_card_free(card);
609 	return err;
610 }
611 
612 static int __devexit snd_dummy_remove(struct platform_device *devptr)
613 {
614 	snd_card_free(platform_get_drvdata(devptr));
615 	platform_set_drvdata(devptr, NULL);
616 	return 0;
617 }
618 
619 #ifdef CONFIG_PM
620 static int snd_dummy_suspend(struct platform_device *pdev, pm_message_t state)
621 {
622 	struct snd_card *card = platform_get_drvdata(pdev);
623 	struct snd_dummy *dummy = card->private_data;
624 
625 	snd_power_change_state(card, SNDRV_CTL_POWER_D3hot);
626 	snd_pcm_suspend_all(dummy->pcm);
627 	return 0;
628 }
629 
630 static int snd_dummy_resume(struct platform_device *pdev)
631 {
632 	struct snd_card *card = platform_get_drvdata(pdev);
633 
634 	snd_power_change_state(card, SNDRV_CTL_POWER_D0);
635 	return 0;
636 }
637 #endif
638 
639 #define SND_DUMMY_DRIVER	"snd_dummy"
640 
641 static struct platform_driver snd_dummy_driver = {
642 	.probe		= snd_dummy_probe,
643 	.remove		= __devexit_p(snd_dummy_remove),
644 #ifdef CONFIG_PM
645 	.suspend	= snd_dummy_suspend,
646 	.resume		= snd_dummy_resume,
647 #endif
648 	.driver		= {
649 		.name	= SND_DUMMY_DRIVER
650 	},
651 };
652 
653 static void snd_dummy_unregister_all(void)
654 {
655 	int i;
656 
657 	for (i = 0; i < ARRAY_SIZE(devices); ++i)
658 		platform_device_unregister(devices[i]);
659 	platform_driver_unregister(&snd_dummy_driver);
660 }
661 
662 static int __init alsa_card_dummy_init(void)
663 {
664 	int i, cards, err;
665 
666 	if ((err = platform_driver_register(&snd_dummy_driver)) < 0)
667 		return err;
668 
669 	cards = 0;
670 	for (i = 0; i < SNDRV_CARDS; i++) {
671 		struct platform_device *device;
672 		if (! enable[i])
673 			continue;
674 		device = platform_device_register_simple(SND_DUMMY_DRIVER,
675 							 i, NULL, 0);
676 		if (IS_ERR(device))
677 			continue;
678 		if (!platform_get_drvdata(device)) {
679 			platform_device_unregister(device);
680 			continue;
681 		}
682 		devices[i] = device;
683 		cards++;
684 	}
685 	if (!cards) {
686 #ifdef MODULE
687 		printk(KERN_ERR "Dummy soundcard not found or device busy\n");
688 #endif
689 		snd_dummy_unregister_all();
690 		return -ENODEV;
691 	}
692 	return 0;
693 }
694 
695 static void __exit alsa_card_dummy_exit(void)
696 {
697 	snd_dummy_unregister_all();
698 }
699 
700 module_init(alsa_card_dummy_init)
701 module_exit(alsa_card_dummy_exit)
702