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v3.15
  1/*
  2 * Apple iSight audio driver
  3 *
  4 * Copyright (c) Clemens Ladisch <clemens@ladisch.de>
  5 * Licensed under the terms of the GNU General Public License, version 2.
  6 */
  7
  8#include <asm/byteorder.h>
  9#include <linux/delay.h>
 10#include <linux/device.h>
 11#include <linux/firewire.h>
 12#include <linux/firewire-constants.h>
 13#include <linux/module.h>
 14#include <linux/mod_devicetable.h>
 15#include <linux/mutex.h>
 16#include <linux/string.h>
 17#include <sound/control.h>
 18#include <sound/core.h>
 19#include <sound/initval.h>
 20#include <sound/pcm.h>
 21#include <sound/tlv.h>
 22#include "lib.h"
 23#include "iso-resources.h"
 24#include "packets-buffer.h"
 25
 26#define OUI_APPLE		0x000a27
 27#define MODEL_APPLE_ISIGHT	0x000008
 28#define SW_ISIGHT_AUDIO		0x000010
 29
 30#define REG_AUDIO_ENABLE	0x000
 31#define  AUDIO_ENABLE		0x80000000
 32#define REG_DEF_AUDIO_GAIN	0x204
 33#define REG_GAIN_RAW_START	0x210
 34#define REG_GAIN_RAW_END	0x214
 35#define REG_GAIN_DB_START	0x218
 36#define REG_GAIN_DB_END		0x21c
 37#define REG_SAMPLE_RATE_INQUIRY	0x280
 38#define REG_ISO_TX_CONFIG	0x300
 39#define  SPEED_SHIFT		16
 40#define REG_SAMPLE_RATE		0x400
 41#define  RATE_48000		0x80000000
 42#define REG_GAIN		0x500
 43#define REG_MUTE		0x504
 44
 45#define MAX_FRAMES_PER_PACKET	475
 46
 47#define QUEUE_LENGTH		20
 48
 49struct isight {
 50	struct snd_card *card;
 51	struct fw_unit *unit;
 52	struct fw_device *device;
 53	u64 audio_base;
 
 54	struct snd_pcm_substream *pcm;
 55	struct mutex mutex;
 56	struct iso_packets_buffer buffer;
 57	struct fw_iso_resources resources;
 58	struct fw_iso_context *context;
 59	bool pcm_active;
 60	bool pcm_running;
 61	bool first_packet;
 62	int packet_index;
 63	u32 total_samples;
 64	unsigned int buffer_pointer;
 65	unsigned int period_counter;
 66	s32 gain_min, gain_max;
 67	unsigned int gain_tlv[4];
 68};
 69
 70struct audio_payload {
 71	__be32 sample_count;
 72	__be32 signature;
 73	__be32 sample_total;
 74	__be32 reserved;
 75	__be16 samples[2 * MAX_FRAMES_PER_PACKET];
 76};
 77
 78MODULE_DESCRIPTION("iSight audio driver");
 79MODULE_AUTHOR("Clemens Ladisch <clemens@ladisch.de>");
 80MODULE_LICENSE("GPL v2");
 81
 82static struct fw_iso_packet audio_packet = {
 83	.payload_length = sizeof(struct audio_payload),
 84	.interrupt = 1,
 85	.header_length = 4,
 86};
 87
 88static void isight_update_pointers(struct isight *isight, unsigned int count)
 89{
 90	struct snd_pcm_runtime *runtime = isight->pcm->runtime;
 91	unsigned int ptr;
 92
 93	smp_wmb(); /* update buffer data before buffer pointer */
 94
 95	ptr = isight->buffer_pointer;
 96	ptr += count;
 97	if (ptr >= runtime->buffer_size)
 98		ptr -= runtime->buffer_size;
 99	ACCESS_ONCE(isight->buffer_pointer) = ptr;
100
101	isight->period_counter += count;
102	if (isight->period_counter >= runtime->period_size) {
103		isight->period_counter -= runtime->period_size;
104		snd_pcm_period_elapsed(isight->pcm);
105	}
106}
107
108static void isight_samples(struct isight *isight,
109			   const __be16 *samples, unsigned int count)
110{
111	struct snd_pcm_runtime *runtime;
112	unsigned int count1;
113
114	if (!ACCESS_ONCE(isight->pcm_running))
115		return;
116
117	runtime = isight->pcm->runtime;
118	if (isight->buffer_pointer + count <= runtime->buffer_size) {
119		memcpy(runtime->dma_area + isight->buffer_pointer * 4,
120		       samples, count * 4);
121	} else {
122		count1 = runtime->buffer_size - isight->buffer_pointer;
123		memcpy(runtime->dma_area + isight->buffer_pointer * 4,
124		       samples, count1 * 4);
125		samples += count1 * 2;
126		memcpy(runtime->dma_area, samples, (count - count1) * 4);
127	}
128
129	isight_update_pointers(isight, count);
130}
131
132static void isight_pcm_abort(struct isight *isight)
133{
134	unsigned long flags;
135
136	if (ACCESS_ONCE(isight->pcm_active)) {
137		snd_pcm_stream_lock_irqsave(isight->pcm, flags);
138		if (snd_pcm_running(isight->pcm))
139			snd_pcm_stop(isight->pcm, SNDRV_PCM_STATE_XRUN);
140		snd_pcm_stream_unlock_irqrestore(isight->pcm, flags);
141	}
142}
143
144static void isight_dropped_samples(struct isight *isight, unsigned int total)
145{
146	struct snd_pcm_runtime *runtime;
147	u32 dropped;
148	unsigned int count1;
149
150	if (!ACCESS_ONCE(isight->pcm_running))
151		return;
152
153	runtime = isight->pcm->runtime;
154	dropped = total - isight->total_samples;
155	if (dropped < runtime->buffer_size) {
156		if (isight->buffer_pointer + dropped <= runtime->buffer_size) {
157			memset(runtime->dma_area + isight->buffer_pointer * 4,
158			       0, dropped * 4);
159		} else {
160			count1 = runtime->buffer_size - isight->buffer_pointer;
161			memset(runtime->dma_area + isight->buffer_pointer * 4,
162			       0, count1 * 4);
163			memset(runtime->dma_area, 0, (dropped - count1) * 4);
164		}
165		isight_update_pointers(isight, dropped);
166	} else {
167		isight_pcm_abort(isight);
168	}
169}
170
171static void isight_packet(struct fw_iso_context *context, u32 cycle,
172			  size_t header_length, void *header, void *data)
173{
174	struct isight *isight = data;
175	const struct audio_payload *payload;
176	unsigned int index, length, count, total;
177	int err;
178
179	if (isight->packet_index < 0)
180		return;
181	index = isight->packet_index;
182	payload = isight->buffer.packets[index].buffer;
183	length = be32_to_cpup(header) >> 16;
184
185	if (likely(length >= 16 &&
186		   payload->signature == cpu_to_be32(0x73676874/*"sght"*/))) {
187		count = be32_to_cpu(payload->sample_count);
188		if (likely(count <= (length - 16) / 4)) {
189			total = be32_to_cpu(payload->sample_total);
190			if (unlikely(total != isight->total_samples)) {
191				if (!isight->first_packet)
192					isight_dropped_samples(isight, total);
193				isight->first_packet = false;
194				isight->total_samples = total;
195			}
196
197			isight_samples(isight, payload->samples, count);
198			isight->total_samples += count;
199		}
200	}
201
202	err = fw_iso_context_queue(isight->context, &audio_packet,
203				   &isight->buffer.iso_buffer,
204				   isight->buffer.packets[index].offset);
205	if (err < 0) {
206		dev_err(&isight->unit->device, "queueing error: %d\n", err);
207		isight_pcm_abort(isight);
208		isight->packet_index = -1;
209		return;
210	}
211	fw_iso_context_queue_flush(isight->context);
212
213	if (++index >= QUEUE_LENGTH)
214		index = 0;
215	isight->packet_index = index;
216}
217
218static int isight_connect(struct isight *isight)
219{
220	int ch, err;
221	__be32 value;
222
223retry_after_bus_reset:
224	ch = fw_iso_resources_allocate(&isight->resources,
225				       sizeof(struct audio_payload),
226				       isight->device->max_speed);
227	if (ch < 0) {
228		err = ch;
229		goto error;
230	}
231
232	value = cpu_to_be32(ch | (isight->device->max_speed << SPEED_SHIFT));
233	err = snd_fw_transaction(isight->unit, TCODE_WRITE_QUADLET_REQUEST,
234				 isight->audio_base + REG_ISO_TX_CONFIG,
235				 &value, 4, FW_FIXED_GENERATION |
236				 isight->resources.generation);
237	if (err == -EAGAIN) {
238		fw_iso_resources_free(&isight->resources);
239		goto retry_after_bus_reset;
240	} else if (err < 0) {
241		goto err_resources;
 
 
 
 
 
 
 
 
 
 
242	}
243
244	return 0;
245
246err_resources:
247	fw_iso_resources_free(&isight->resources);
248error:
249	return err;
250}
251
252static int isight_open(struct snd_pcm_substream *substream)
253{
254	static const struct snd_pcm_hardware hardware = {
255		.info = SNDRV_PCM_INFO_MMAP |
256			SNDRV_PCM_INFO_MMAP_VALID |
257			SNDRV_PCM_INFO_BATCH |
258			SNDRV_PCM_INFO_INTERLEAVED |
259			SNDRV_PCM_INFO_BLOCK_TRANSFER,
260		.formats = SNDRV_PCM_FMTBIT_S16_BE,
261		.rates = SNDRV_PCM_RATE_48000,
262		.rate_min = 48000,
263		.rate_max = 48000,
264		.channels_min = 2,
265		.channels_max = 2,
266		.buffer_bytes_max = 4 * 1024 * 1024,
267		.period_bytes_min = MAX_FRAMES_PER_PACKET * 4,
268		.period_bytes_max = 1024 * 1024,
269		.periods_min = 2,
270		.periods_max = UINT_MAX,
271	};
272	struct isight *isight = substream->private_data;
273
274	substream->runtime->hw = hardware;
275
276	return iso_packets_buffer_init(&isight->buffer, isight->unit,
277				       QUEUE_LENGTH,
278				       sizeof(struct audio_payload),
279				       DMA_FROM_DEVICE);
280}
281
282static int isight_close(struct snd_pcm_substream *substream)
283{
284	struct isight *isight = substream->private_data;
285
286	iso_packets_buffer_destroy(&isight->buffer, isight->unit);
287
288	return 0;
289}
290
291static int isight_hw_params(struct snd_pcm_substream *substream,
292			    struct snd_pcm_hw_params *hw_params)
293{
294	struct isight *isight = substream->private_data;
295	int err;
296
297	err = snd_pcm_lib_alloc_vmalloc_buffer(substream,
298					       params_buffer_bytes(hw_params));
299	if (err < 0)
300		return err;
301
302	ACCESS_ONCE(isight->pcm_active) = true;
303
304	return 0;
305}
306
307static int reg_read(struct isight *isight, int offset, __be32 *value)
308{
309	return snd_fw_transaction(isight->unit, TCODE_READ_QUADLET_REQUEST,
310				  isight->audio_base + offset, value, 4, 0);
311}
312
313static int reg_write(struct isight *isight, int offset, __be32 value)
314{
315	return snd_fw_transaction(isight->unit, TCODE_WRITE_QUADLET_REQUEST,
316				  isight->audio_base + offset, &value, 4, 0);
317}
318
319static void isight_stop_streaming(struct isight *isight)
320{
321	__be32 value;
322
323	if (!isight->context)
324		return;
325
326	fw_iso_context_stop(isight->context);
327	fw_iso_context_destroy(isight->context);
328	isight->context = NULL;
329	fw_iso_resources_free(&isight->resources);
330	value = 0;
331	snd_fw_transaction(isight->unit, TCODE_WRITE_QUADLET_REQUEST,
332			   isight->audio_base + REG_AUDIO_ENABLE,
333			   &value, 4, FW_QUIET);
334}
335
336static int isight_hw_free(struct snd_pcm_substream *substream)
337{
338	struct isight *isight = substream->private_data;
339
340	ACCESS_ONCE(isight->pcm_active) = false;
341
342	mutex_lock(&isight->mutex);
343	isight_stop_streaming(isight);
344	mutex_unlock(&isight->mutex);
345
346	return snd_pcm_lib_free_vmalloc_buffer(substream);
347}
348
349static int isight_start_streaming(struct isight *isight)
350{
351	unsigned int i;
352	int err;
353
354	if (isight->context) {
355		if (isight->packet_index < 0)
356			isight_stop_streaming(isight);
357		else
358			return 0;
359	}
360
361	err = reg_write(isight, REG_SAMPLE_RATE, cpu_to_be32(RATE_48000));
362	if (err < 0)
363		goto error;
364
365	err = isight_connect(isight);
366	if (err < 0)
367		goto error;
368
369	err = reg_write(isight, REG_AUDIO_ENABLE, cpu_to_be32(AUDIO_ENABLE));
370	if (err < 0)
371		goto err_resources;
372
373	isight->context = fw_iso_context_create(isight->device->card,
374						FW_ISO_CONTEXT_RECEIVE,
375						isight->resources.channel,
376						isight->device->max_speed,
377						4, isight_packet, isight);
378	if (IS_ERR(isight->context)) {
379		err = PTR_ERR(isight->context);
380		isight->context = NULL;
381		goto err_resources;
382	}
383
384	for (i = 0; i < QUEUE_LENGTH; ++i) {
385		err = fw_iso_context_queue(isight->context, &audio_packet,
386					   &isight->buffer.iso_buffer,
387					   isight->buffer.packets[i].offset);
388		if (err < 0)
389			goto err_context;
390	}
391
392	isight->first_packet = true;
393	isight->packet_index = 0;
394
395	err = fw_iso_context_start(isight->context, -1, 0,
396				   FW_ISO_CONTEXT_MATCH_ALL_TAGS/*?*/);
397	if (err < 0)
398		goto err_context;
399
400	return 0;
401
402err_context:
403	fw_iso_context_destroy(isight->context);
404	isight->context = NULL;
405err_resources:
406	fw_iso_resources_free(&isight->resources);
407	reg_write(isight, REG_AUDIO_ENABLE, 0);
408error:
409	return err;
410}
411
412static int isight_prepare(struct snd_pcm_substream *substream)
413{
414	struct isight *isight = substream->private_data;
415	int err;
416
417	isight->buffer_pointer = 0;
418	isight->period_counter = 0;
419
420	mutex_lock(&isight->mutex);
421	err = isight_start_streaming(isight);
422	mutex_unlock(&isight->mutex);
423
424	return err;
425}
426
427static int isight_trigger(struct snd_pcm_substream *substream, int cmd)
428{
429	struct isight *isight = substream->private_data;
430
431	switch (cmd) {
432	case SNDRV_PCM_TRIGGER_START:
433		ACCESS_ONCE(isight->pcm_running) = true;
434		break;
435	case SNDRV_PCM_TRIGGER_STOP:
436		ACCESS_ONCE(isight->pcm_running) = false;
437		break;
438	default:
439		return -EINVAL;
440	}
441	return 0;
442}
443
444static snd_pcm_uframes_t isight_pointer(struct snd_pcm_substream *substream)
445{
446	struct isight *isight = substream->private_data;
447
448	return ACCESS_ONCE(isight->buffer_pointer);
449}
450
451static int isight_create_pcm(struct isight *isight)
452{
453	static struct snd_pcm_ops ops = {
454		.open      = isight_open,
455		.close     = isight_close,
456		.ioctl     = snd_pcm_lib_ioctl,
457		.hw_params = isight_hw_params,
458		.hw_free   = isight_hw_free,
459		.prepare   = isight_prepare,
460		.trigger   = isight_trigger,
461		.pointer   = isight_pointer,
462		.page      = snd_pcm_lib_get_vmalloc_page,
463		.mmap      = snd_pcm_lib_mmap_vmalloc,
464	};
465	struct snd_pcm *pcm;
466	int err;
467
468	err = snd_pcm_new(isight->card, "iSight", 0, 0, 1, &pcm);
469	if (err < 0)
470		return err;
471	pcm->private_data = isight;
472	strcpy(pcm->name, "iSight");
473	isight->pcm = pcm->streams[SNDRV_PCM_STREAM_CAPTURE].substream;
474	isight->pcm->ops = &ops;
475
476	return 0;
477}
478
479static int isight_gain_info(struct snd_kcontrol *ctl,
480			    struct snd_ctl_elem_info *info)
481{
482	struct isight *isight = ctl->private_data;
483
484	info->type = SNDRV_CTL_ELEM_TYPE_INTEGER;
485	info->count = 1;
486	info->value.integer.min = isight->gain_min;
487	info->value.integer.max = isight->gain_max;
488
489	return 0;
490}
491
492static int isight_gain_get(struct snd_kcontrol *ctl,
493			   struct snd_ctl_elem_value *value)
494{
495	struct isight *isight = ctl->private_data;
496	__be32 gain;
497	int err;
498
499	err = reg_read(isight, REG_GAIN, &gain);
500	if (err < 0)
501		return err;
502
503	value->value.integer.value[0] = (s32)be32_to_cpu(gain);
504
505	return 0;
506}
507
508static int isight_gain_put(struct snd_kcontrol *ctl,
509			   struct snd_ctl_elem_value *value)
510{
511	struct isight *isight = ctl->private_data;
512
513	if (value->value.integer.value[0] < isight->gain_min ||
514	    value->value.integer.value[0] > isight->gain_max)
515		return -EINVAL;
516
517	return reg_write(isight, REG_GAIN,
518			 cpu_to_be32(value->value.integer.value[0]));
519}
520
521static int isight_mute_get(struct snd_kcontrol *ctl,
522			   struct snd_ctl_elem_value *value)
523{
524	struct isight *isight = ctl->private_data;
525	__be32 mute;
526	int err;
527
528	err = reg_read(isight, REG_MUTE, &mute);
529	if (err < 0)
530		return err;
531
532	value->value.integer.value[0] = !mute;
533
534	return 0;
535}
536
537static int isight_mute_put(struct snd_kcontrol *ctl,
538			   struct snd_ctl_elem_value *value)
539{
540	struct isight *isight = ctl->private_data;
541
542	return reg_write(isight, REG_MUTE,
543			 (__force __be32)!value->value.integer.value[0]);
544}
545
546static int isight_create_mixer(struct isight *isight)
547{
548	static const struct snd_kcontrol_new gain_control = {
549		.iface = SNDRV_CTL_ELEM_IFACE_MIXER,
550		.name = "Mic Capture Volume",
551		.access = SNDRV_CTL_ELEM_ACCESS_READWRITE |
552			  SNDRV_CTL_ELEM_ACCESS_TLV_READ,
553		.info = isight_gain_info,
554		.get = isight_gain_get,
555		.put = isight_gain_put,
556	};
557	static const struct snd_kcontrol_new mute_control = {
558		.iface = SNDRV_CTL_ELEM_IFACE_MIXER,
559		.name = "Mic Capture Switch",
560		.info = snd_ctl_boolean_mono_info,
561		.get = isight_mute_get,
562		.put = isight_mute_put,
563	};
564	__be32 value;
565	struct snd_kcontrol *ctl;
566	int err;
567
568	err = reg_read(isight, REG_GAIN_RAW_START, &value);
569	if (err < 0)
570		return err;
571	isight->gain_min = be32_to_cpu(value);
572
573	err = reg_read(isight, REG_GAIN_RAW_END, &value);
574	if (err < 0)
575		return err;
576	isight->gain_max = be32_to_cpu(value);
577
578	isight->gain_tlv[0] = SNDRV_CTL_TLVT_DB_MINMAX;
579	isight->gain_tlv[1] = 2 * sizeof(unsigned int);
580
581	err = reg_read(isight, REG_GAIN_DB_START, &value);
582	if (err < 0)
583		return err;
584	isight->gain_tlv[2] = (s32)be32_to_cpu(value) * 100;
585
586	err = reg_read(isight, REG_GAIN_DB_END, &value);
587	if (err < 0)
588		return err;
589	isight->gain_tlv[3] = (s32)be32_to_cpu(value) * 100;
590
591	ctl = snd_ctl_new1(&gain_control, isight);
592	if (ctl)
593		ctl->tlv.p = isight->gain_tlv;
594	err = snd_ctl_add(isight->card, ctl);
595	if (err < 0)
596		return err;
597
598	err = snd_ctl_add(isight->card, snd_ctl_new1(&mute_control, isight));
599	if (err < 0)
600		return err;
601
602	return 0;
603}
604
605static void isight_card_free(struct snd_card *card)
606{
607	struct isight *isight = card->private_data;
608
609	fw_iso_resources_destroy(&isight->resources);
610	fw_unit_put(isight->unit);
 
611	mutex_destroy(&isight->mutex);
612}
613
614static u64 get_unit_base(struct fw_unit *unit)
615{
616	struct fw_csr_iterator i;
617	int key, value;
618
619	fw_csr_iterator_init(&i, unit->directory);
620	while (fw_csr_iterator_next(&i, &key, &value))
621		if (key == CSR_OFFSET)
622			return CSR_REGISTER_BASE + value * 4;
623	return 0;
624}
625
626static int isight_probe(struct fw_unit *unit,
627			const struct ieee1394_device_id *id)
628{
 
629	struct fw_device *fw_dev = fw_parent_device(unit);
630	struct snd_card *card;
631	struct isight *isight;
632	int err;
633
634	err = snd_card_new(&unit->device, -1, NULL, THIS_MODULE,
635			   sizeof(*isight), &card);
636	if (err < 0)
637		return err;
 
638
639	isight = card->private_data;
640	isight->card = card;
641	mutex_init(&isight->mutex);
642	isight->unit = fw_unit_get(unit);
643	isight->device = fw_dev;
644	isight->audio_base = get_unit_base(unit);
645	if (!isight->audio_base) {
646		dev_err(&unit->device, "audio unit base not found\n");
647		err = -ENXIO;
648		goto err_unit;
649	}
650	fw_iso_resources_init(&isight->resources, unit);
651
652	card->private_free = isight_card_free;
653
654	strcpy(card->driver, "iSight");
655	strcpy(card->shortname, "Apple iSight");
656	snprintf(card->longname, sizeof(card->longname),
657		 "Apple iSight (GUID %08x%08x) at %s, S%d",
658		 fw_dev->config_rom[3], fw_dev->config_rom[4],
659		 dev_name(&unit->device), 100 << fw_dev->max_speed);
660	strcpy(card->mixername, "iSight");
661
662	err = isight_create_pcm(isight);
663	if (err < 0)
664		goto error;
665
666	err = isight_create_mixer(isight);
667	if (err < 0)
668		goto error;
669
670	err = snd_card_register(card);
671	if (err < 0)
672		goto error;
673
674	dev_set_drvdata(&unit->device, isight);
675
676	return 0;
677
678err_unit:
679	fw_unit_put(isight->unit);
 
680	mutex_destroy(&isight->mutex);
681error:
682	snd_card_free(card);
683	return err;
684}
685
686static void isight_bus_reset(struct fw_unit *unit)
687{
688	struct isight *isight = dev_get_drvdata(&unit->device);
689
690	if (fw_iso_resources_update(&isight->resources) < 0) {
691		isight_pcm_abort(isight);
692
693		mutex_lock(&isight->mutex);
694		isight_stop_streaming(isight);
695		mutex_unlock(&isight->mutex);
696	}
697}
698
699static void isight_remove(struct fw_unit *unit)
700{
701	struct isight *isight = dev_get_drvdata(&unit->device);
702
703	isight_pcm_abort(isight);
704
705	snd_card_disconnect(isight->card);
706
707	mutex_lock(&isight->mutex);
708	isight_stop_streaming(isight);
709	mutex_unlock(&isight->mutex);
710
711	snd_card_free_when_closed(isight->card);
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
712}
713
714static const struct ieee1394_device_id isight_id_table[] = {
715	{
716		.match_flags  = IEEE1394_MATCH_SPECIFIER_ID |
717				IEEE1394_MATCH_VERSION,
718		.specifier_id = OUI_APPLE,
719		.version      = SW_ISIGHT_AUDIO,
720	},
721	{ }
722};
723MODULE_DEVICE_TABLE(ieee1394, isight_id_table);
724
725static struct fw_driver isight_driver = {
726	.driver   = {
727		.owner	= THIS_MODULE,
728		.name	= KBUILD_MODNAME,
729		.bus	= &fw_bus_type,
 
 
730	},
731	.probe    = isight_probe,
732	.update   = isight_bus_reset,
733	.remove   = isight_remove,
734	.id_table = isight_id_table,
735};
736
737static int __init alsa_isight_init(void)
738{
739	return driver_register(&isight_driver.driver);
740}
741
742static void __exit alsa_isight_exit(void)
743{
744	driver_unregister(&isight_driver.driver);
745}
746
747module_init(alsa_isight_init);
748module_exit(alsa_isight_exit);
v3.1
  1/*
  2 * Apple iSight audio driver
  3 *
  4 * Copyright (c) Clemens Ladisch <clemens@ladisch.de>
  5 * Licensed under the terms of the GNU General Public License, version 2.
  6 */
  7
  8#include <asm/byteorder.h>
  9#include <linux/delay.h>
 10#include <linux/device.h>
 11#include <linux/firewire.h>
 12#include <linux/firewire-constants.h>
 13#include <linux/module.h>
 14#include <linux/mod_devicetable.h>
 15#include <linux/mutex.h>
 16#include <linux/string.h>
 17#include <sound/control.h>
 18#include <sound/core.h>
 19#include <sound/initval.h>
 20#include <sound/pcm.h>
 21#include <sound/tlv.h>
 22#include "lib.h"
 23#include "iso-resources.h"
 24#include "packets-buffer.h"
 25
 26#define OUI_APPLE		0x000a27
 27#define MODEL_APPLE_ISIGHT	0x000008
 28#define SW_ISIGHT_AUDIO		0x000010
 29
 30#define REG_AUDIO_ENABLE	0x000
 31#define  AUDIO_ENABLE		0x80000000
 32#define REG_DEF_AUDIO_GAIN	0x204
 33#define REG_GAIN_RAW_START	0x210
 34#define REG_GAIN_RAW_END	0x214
 35#define REG_GAIN_DB_START	0x218
 36#define REG_GAIN_DB_END		0x21c
 37#define REG_SAMPLE_RATE_INQUIRY	0x280
 38#define REG_ISO_TX_CONFIG	0x300
 39#define  SPEED_SHIFT		16
 40#define REG_SAMPLE_RATE		0x400
 41#define  RATE_48000		0x80000000
 42#define REG_GAIN		0x500
 43#define REG_MUTE		0x504
 44
 45#define MAX_FRAMES_PER_PACKET	475
 46
 47#define QUEUE_LENGTH		20
 48
 49struct isight {
 50	struct snd_card *card;
 51	struct fw_unit *unit;
 52	struct fw_device *device;
 53	u64 audio_base;
 54	struct fw_address_handler iris_handler;
 55	struct snd_pcm_substream *pcm;
 56	struct mutex mutex;
 57	struct iso_packets_buffer buffer;
 58	struct fw_iso_resources resources;
 59	struct fw_iso_context *context;
 60	bool pcm_active;
 61	bool pcm_running;
 62	bool first_packet;
 63	int packet_index;
 64	u32 total_samples;
 65	unsigned int buffer_pointer;
 66	unsigned int period_counter;
 67	s32 gain_min, gain_max;
 68	unsigned int gain_tlv[4];
 69};
 70
 71struct audio_payload {
 72	__be32 sample_count;
 73	__be32 signature;
 74	__be32 sample_total;
 75	__be32 reserved;
 76	__be16 samples[2 * MAX_FRAMES_PER_PACKET];
 77};
 78
 79MODULE_DESCRIPTION("iSight audio driver");
 80MODULE_AUTHOR("Clemens Ladisch <clemens@ladisch.de>");
 81MODULE_LICENSE("GPL v2");
 82
 83static struct fw_iso_packet audio_packet = {
 84	.payload_length = sizeof(struct audio_payload),
 85	.interrupt = 1,
 86	.header_length = 4,
 87};
 88
 89static void isight_update_pointers(struct isight *isight, unsigned int count)
 90{
 91	struct snd_pcm_runtime *runtime = isight->pcm->runtime;
 92	unsigned int ptr;
 93
 94	smp_wmb(); /* update buffer data before buffer pointer */
 95
 96	ptr = isight->buffer_pointer;
 97	ptr += count;
 98	if (ptr >= runtime->buffer_size)
 99		ptr -= runtime->buffer_size;
100	ACCESS_ONCE(isight->buffer_pointer) = ptr;
101
102	isight->period_counter += count;
103	if (isight->period_counter >= runtime->period_size) {
104		isight->period_counter -= runtime->period_size;
105		snd_pcm_period_elapsed(isight->pcm);
106	}
107}
108
109static void isight_samples(struct isight *isight,
110			   const __be16 *samples, unsigned int count)
111{
112	struct snd_pcm_runtime *runtime;
113	unsigned int count1;
114
115	if (!ACCESS_ONCE(isight->pcm_running))
116		return;
117
118	runtime = isight->pcm->runtime;
119	if (isight->buffer_pointer + count <= runtime->buffer_size) {
120		memcpy(runtime->dma_area + isight->buffer_pointer * 4,
121		       samples, count * 4);
122	} else {
123		count1 = runtime->buffer_size - isight->buffer_pointer;
124		memcpy(runtime->dma_area + isight->buffer_pointer * 4,
125		       samples, count1 * 4);
126		samples += count1 * 2;
127		memcpy(runtime->dma_area, samples, (count - count1) * 4);
128	}
129
130	isight_update_pointers(isight, count);
131}
132
133static void isight_pcm_abort(struct isight *isight)
134{
135	unsigned long flags;
136
137	if (ACCESS_ONCE(isight->pcm_active)) {
138		snd_pcm_stream_lock_irqsave(isight->pcm, flags);
139		if (snd_pcm_running(isight->pcm))
140			snd_pcm_stop(isight->pcm, SNDRV_PCM_STATE_XRUN);
141		snd_pcm_stream_unlock_irqrestore(isight->pcm, flags);
142	}
143}
144
145static void isight_dropped_samples(struct isight *isight, unsigned int total)
146{
147	struct snd_pcm_runtime *runtime;
148	u32 dropped;
149	unsigned int count1;
150
151	if (!ACCESS_ONCE(isight->pcm_running))
152		return;
153
154	runtime = isight->pcm->runtime;
155	dropped = total - isight->total_samples;
156	if (dropped < runtime->buffer_size) {
157		if (isight->buffer_pointer + dropped <= runtime->buffer_size) {
158			memset(runtime->dma_area + isight->buffer_pointer * 4,
159			       0, dropped * 4);
160		} else {
161			count1 = runtime->buffer_size - isight->buffer_pointer;
162			memset(runtime->dma_area + isight->buffer_pointer * 4,
163			       0, count1 * 4);
164			memset(runtime->dma_area, 0, (dropped - count1) * 4);
165		}
166		isight_update_pointers(isight, dropped);
167	} else {
168		isight_pcm_abort(isight);
169	}
170}
171
172static void isight_packet(struct fw_iso_context *context, u32 cycle,
173			  size_t header_length, void *header, void *data)
174{
175	struct isight *isight = data;
176	const struct audio_payload *payload;
177	unsigned int index, length, count, total;
178	int err;
179
180	if (isight->packet_index < 0)
181		return;
182	index = isight->packet_index;
183	payload = isight->buffer.packets[index].buffer;
184	length = be32_to_cpup(header) >> 16;
185
186	if (likely(length >= 16 &&
187		   payload->signature == cpu_to_be32(0x73676874/*"sght"*/))) {
188		count = be32_to_cpu(payload->sample_count);
189		if (likely(count <= (length - 16) / 4)) {
190			total = be32_to_cpu(payload->sample_total);
191			if (unlikely(total != isight->total_samples)) {
192				if (!isight->first_packet)
193					isight_dropped_samples(isight, total);
194				isight->first_packet = false;
195				isight->total_samples = total;
196			}
197
198			isight_samples(isight, payload->samples, count);
199			isight->total_samples += count;
200		}
201	}
202
203	err = fw_iso_context_queue(isight->context, &audio_packet,
204				   &isight->buffer.iso_buffer,
205				   isight->buffer.packets[index].offset);
206	if (err < 0) {
207		dev_err(&isight->unit->device, "queueing error: %d\n", err);
208		isight_pcm_abort(isight);
209		isight->packet_index = -1;
210		return;
211	}
212	fw_iso_context_queue_flush(isight->context);
213
214	if (++index >= QUEUE_LENGTH)
215		index = 0;
216	isight->packet_index = index;
217}
218
219static int isight_connect(struct isight *isight)
220{
221	int ch, err, rcode, errors = 0;
222	__be32 value;
223
224retry_after_bus_reset:
225	ch = fw_iso_resources_allocate(&isight->resources,
226				       sizeof(struct audio_payload),
227				       isight->device->max_speed);
228	if (ch < 0) {
229		err = ch;
230		goto error;
231	}
232
233	value = cpu_to_be32(ch | (isight->device->max_speed << SPEED_SHIFT));
234	for (;;) {
235		rcode = fw_run_transaction(
236				isight->device->card,
237				TCODE_WRITE_QUADLET_REQUEST,
238				isight->device->node_id,
239				isight->resources.generation,
240				isight->device->max_speed,
241				isight->audio_base + REG_ISO_TX_CONFIG,
242				&value, 4);
243		if (rcode == RCODE_COMPLETE) {
244			return 0;
245		} else if (rcode == RCODE_GENERATION) {
246			fw_iso_resources_free(&isight->resources);
247			goto retry_after_bus_reset;
248		} else if (rcode_is_permanent_error(rcode) || ++errors >= 3) {
249			err = -EIO;
250			goto err_resources;
251		}
252		msleep(5);
253	}
254
 
 
255err_resources:
256	fw_iso_resources_free(&isight->resources);
257error:
258	return err;
259}
260
261static int isight_open(struct snd_pcm_substream *substream)
262{
263	static const struct snd_pcm_hardware hardware = {
264		.info = SNDRV_PCM_INFO_MMAP |
265			SNDRV_PCM_INFO_MMAP_VALID |
266			SNDRV_PCM_INFO_BATCH |
267			SNDRV_PCM_INFO_INTERLEAVED |
268			SNDRV_PCM_INFO_BLOCK_TRANSFER,
269		.formats = SNDRV_PCM_FMTBIT_S16_BE,
270		.rates = SNDRV_PCM_RATE_48000,
271		.rate_min = 48000,
272		.rate_max = 48000,
273		.channels_min = 2,
274		.channels_max = 2,
275		.buffer_bytes_max = 4 * 1024 * 1024,
276		.period_bytes_min = MAX_FRAMES_PER_PACKET * 4,
277		.period_bytes_max = 1024 * 1024,
278		.periods_min = 2,
279		.periods_max = UINT_MAX,
280	};
281	struct isight *isight = substream->private_data;
282
283	substream->runtime->hw = hardware;
284
285	return iso_packets_buffer_init(&isight->buffer, isight->unit,
286				       QUEUE_LENGTH,
287				       sizeof(struct audio_payload),
288				       DMA_FROM_DEVICE);
289}
290
291static int isight_close(struct snd_pcm_substream *substream)
292{
293	struct isight *isight = substream->private_data;
294
295	iso_packets_buffer_destroy(&isight->buffer, isight->unit);
296
297	return 0;
298}
299
300static int isight_hw_params(struct snd_pcm_substream *substream,
301			    struct snd_pcm_hw_params *hw_params)
302{
303	struct isight *isight = substream->private_data;
304	int err;
305
306	err = snd_pcm_lib_alloc_vmalloc_buffer(substream,
307					       params_buffer_bytes(hw_params));
308	if (err < 0)
309		return err;
310
311	ACCESS_ONCE(isight->pcm_active) = true;
312
313	return 0;
314}
315
316static int reg_read(struct isight *isight, int offset, __be32 *value)
317{
318	return snd_fw_transaction(isight->unit, TCODE_READ_QUADLET_REQUEST,
319				  isight->audio_base + offset, value, 4);
320}
321
322static int reg_write(struct isight *isight, int offset, __be32 value)
323{
324	return snd_fw_transaction(isight->unit, TCODE_WRITE_QUADLET_REQUEST,
325				  isight->audio_base + offset, &value, 4);
326}
327
328static void isight_stop_streaming(struct isight *isight)
329{
 
 
330	if (!isight->context)
331		return;
332
333	fw_iso_context_stop(isight->context);
334	fw_iso_context_destroy(isight->context);
335	isight->context = NULL;
336	fw_iso_resources_free(&isight->resources);
337	reg_write(isight, REG_AUDIO_ENABLE, 0);
 
 
 
338}
339
340static int isight_hw_free(struct snd_pcm_substream *substream)
341{
342	struct isight *isight = substream->private_data;
343
344	ACCESS_ONCE(isight->pcm_active) = false;
345
346	mutex_lock(&isight->mutex);
347	isight_stop_streaming(isight);
348	mutex_unlock(&isight->mutex);
349
350	return snd_pcm_lib_free_vmalloc_buffer(substream);
351}
352
353static int isight_start_streaming(struct isight *isight)
354{
355	unsigned int i;
356	int err;
357
358	if (isight->context) {
359		if (isight->packet_index < 0)
360			isight_stop_streaming(isight);
361		else
362			return 0;
363	}
364
365	err = reg_write(isight, REG_SAMPLE_RATE, cpu_to_be32(RATE_48000));
366	if (err < 0)
367		goto error;
368
369	err = isight_connect(isight);
370	if (err < 0)
371		goto error;
372
373	err = reg_write(isight, REG_AUDIO_ENABLE, cpu_to_be32(AUDIO_ENABLE));
374	if (err < 0)
375		goto err_resources;
376
377	isight->context = fw_iso_context_create(isight->device->card,
378						FW_ISO_CONTEXT_RECEIVE,
379						isight->resources.channel,
380						isight->device->max_speed,
381						4, isight_packet, isight);
382	if (IS_ERR(isight->context)) {
383		err = PTR_ERR(isight->context);
384		isight->context = NULL;
385		goto err_resources;
386	}
387
388	for (i = 0; i < QUEUE_LENGTH; ++i) {
389		err = fw_iso_context_queue(isight->context, &audio_packet,
390					   &isight->buffer.iso_buffer,
391					   isight->buffer.packets[i].offset);
392		if (err < 0)
393			goto err_context;
394	}
395
396	isight->first_packet = true;
397	isight->packet_index = 0;
398
399	err = fw_iso_context_start(isight->context, -1, 0,
400				   FW_ISO_CONTEXT_MATCH_ALL_TAGS/*?*/);
401	if (err < 0)
402		goto err_context;
403
404	return 0;
405
406err_context:
407	fw_iso_context_destroy(isight->context);
408	isight->context = NULL;
409err_resources:
410	fw_iso_resources_free(&isight->resources);
411	reg_write(isight, REG_AUDIO_ENABLE, 0);
412error:
413	return err;
414}
415
416static int isight_prepare(struct snd_pcm_substream *substream)
417{
418	struct isight *isight = substream->private_data;
419	int err;
420
421	isight->buffer_pointer = 0;
422	isight->period_counter = 0;
423
424	mutex_lock(&isight->mutex);
425	err = isight_start_streaming(isight);
426	mutex_unlock(&isight->mutex);
427
428	return err;
429}
430
431static int isight_trigger(struct snd_pcm_substream *substream, int cmd)
432{
433	struct isight *isight = substream->private_data;
434
435	switch (cmd) {
436	case SNDRV_PCM_TRIGGER_START:
437		ACCESS_ONCE(isight->pcm_running) = true;
438		break;
439	case SNDRV_PCM_TRIGGER_STOP:
440		ACCESS_ONCE(isight->pcm_running) = false;
441		break;
442	default:
443		return -EINVAL;
444	}
445	return 0;
446}
447
448static snd_pcm_uframes_t isight_pointer(struct snd_pcm_substream *substream)
449{
450	struct isight *isight = substream->private_data;
451
452	return ACCESS_ONCE(isight->buffer_pointer);
453}
454
455static int isight_create_pcm(struct isight *isight)
456{
457	static struct snd_pcm_ops ops = {
458		.open      = isight_open,
459		.close     = isight_close,
460		.ioctl     = snd_pcm_lib_ioctl,
461		.hw_params = isight_hw_params,
462		.hw_free   = isight_hw_free,
463		.prepare   = isight_prepare,
464		.trigger   = isight_trigger,
465		.pointer   = isight_pointer,
466		.page      = snd_pcm_lib_get_vmalloc_page,
467		.mmap      = snd_pcm_lib_mmap_vmalloc,
468	};
469	struct snd_pcm *pcm;
470	int err;
471
472	err = snd_pcm_new(isight->card, "iSight", 0, 0, 1, &pcm);
473	if (err < 0)
474		return err;
475	pcm->private_data = isight;
476	strcpy(pcm->name, "iSight");
477	isight->pcm = pcm->streams[SNDRV_PCM_STREAM_CAPTURE].substream;
478	isight->pcm->ops = &ops;
479
480	return 0;
481}
482
483static int isight_gain_info(struct snd_kcontrol *ctl,
484			    struct snd_ctl_elem_info *info)
485{
486	struct isight *isight = ctl->private_data;
487
488	info->type = SNDRV_CTL_ELEM_TYPE_INTEGER;
489	info->count = 1;
490	info->value.integer.min = isight->gain_min;
491	info->value.integer.max = isight->gain_max;
492
493	return 0;
494}
495
496static int isight_gain_get(struct snd_kcontrol *ctl,
497			   struct snd_ctl_elem_value *value)
498{
499	struct isight *isight = ctl->private_data;
500	__be32 gain;
501	int err;
502
503	err = reg_read(isight, REG_GAIN, &gain);
504	if (err < 0)
505		return err;
506
507	value->value.integer.value[0] = (s32)be32_to_cpu(gain);
508
509	return 0;
510}
511
512static int isight_gain_put(struct snd_kcontrol *ctl,
513			   struct snd_ctl_elem_value *value)
514{
515	struct isight *isight = ctl->private_data;
516
517	if (value->value.integer.value[0] < isight->gain_min ||
518	    value->value.integer.value[0] > isight->gain_max)
519		return -EINVAL;
520
521	return reg_write(isight, REG_GAIN,
522			 cpu_to_be32(value->value.integer.value[0]));
523}
524
525static int isight_mute_get(struct snd_kcontrol *ctl,
526			   struct snd_ctl_elem_value *value)
527{
528	struct isight *isight = ctl->private_data;
529	__be32 mute;
530	int err;
531
532	err = reg_read(isight, REG_MUTE, &mute);
533	if (err < 0)
534		return err;
535
536	value->value.integer.value[0] = !mute;
537
538	return 0;
539}
540
541static int isight_mute_put(struct snd_kcontrol *ctl,
542			   struct snd_ctl_elem_value *value)
543{
544	struct isight *isight = ctl->private_data;
545
546	return reg_write(isight, REG_MUTE,
547			 (__force __be32)!value->value.integer.value[0]);
548}
549
550static int isight_create_mixer(struct isight *isight)
551{
552	static const struct snd_kcontrol_new gain_control = {
553		.iface = SNDRV_CTL_ELEM_IFACE_MIXER,
554		.name = "Mic Capture Volume",
555		.access = SNDRV_CTL_ELEM_ACCESS_READWRITE |
556			  SNDRV_CTL_ELEM_ACCESS_TLV_READ,
557		.info = isight_gain_info,
558		.get = isight_gain_get,
559		.put = isight_gain_put,
560	};
561	static const struct snd_kcontrol_new mute_control = {
562		.iface = SNDRV_CTL_ELEM_IFACE_MIXER,
563		.name = "Mic Capture Switch",
564		.info = snd_ctl_boolean_mono_info,
565		.get = isight_mute_get,
566		.put = isight_mute_put,
567	};
568	__be32 value;
569	struct snd_kcontrol *ctl;
570	int err;
571
572	err = reg_read(isight, REG_GAIN_RAW_START, &value);
573	if (err < 0)
574		return err;
575	isight->gain_min = be32_to_cpu(value);
576
577	err = reg_read(isight, REG_GAIN_RAW_END, &value);
578	if (err < 0)
579		return err;
580	isight->gain_max = be32_to_cpu(value);
581
582	isight->gain_tlv[0] = SNDRV_CTL_TLVT_DB_MINMAX;
583	isight->gain_tlv[1] = 2 * sizeof(unsigned int);
584
585	err = reg_read(isight, REG_GAIN_DB_START, &value);
586	if (err < 0)
587		return err;
588	isight->gain_tlv[2] = (s32)be32_to_cpu(value) * 100;
589
590	err = reg_read(isight, REG_GAIN_DB_END, &value);
591	if (err < 0)
592		return err;
593	isight->gain_tlv[3] = (s32)be32_to_cpu(value) * 100;
594
595	ctl = snd_ctl_new1(&gain_control, isight);
596	if (ctl)
597		ctl->tlv.p = isight->gain_tlv;
598	err = snd_ctl_add(isight->card, ctl);
599	if (err < 0)
600		return err;
601
602	err = snd_ctl_add(isight->card, snd_ctl_new1(&mute_control, isight));
603	if (err < 0)
604		return err;
605
606	return 0;
607}
608
609static void isight_card_free(struct snd_card *card)
610{
611	struct isight *isight = card->private_data;
612
613	fw_iso_resources_destroy(&isight->resources);
614	fw_unit_put(isight->unit);
615	fw_device_put(isight->device);
616	mutex_destroy(&isight->mutex);
617}
618
619static u64 get_unit_base(struct fw_unit *unit)
620{
621	struct fw_csr_iterator i;
622	int key, value;
623
624	fw_csr_iterator_init(&i, unit->directory);
625	while (fw_csr_iterator_next(&i, &key, &value))
626		if (key == CSR_OFFSET)
627			return CSR_REGISTER_BASE + value * 4;
628	return 0;
629}
630
631static int isight_probe(struct device *unit_dev)
 
632{
633	struct fw_unit *unit = fw_unit(unit_dev);
634	struct fw_device *fw_dev = fw_parent_device(unit);
635	struct snd_card *card;
636	struct isight *isight;
637	int err;
638
639	err = snd_card_create(-1, NULL, THIS_MODULE, sizeof(*isight), &card);
 
640	if (err < 0)
641		return err;
642	snd_card_set_dev(card, unit_dev);
643
644	isight = card->private_data;
645	isight->card = card;
646	mutex_init(&isight->mutex);
647	isight->unit = fw_unit_get(unit);
648	isight->device = fw_device_get(fw_dev);
649	isight->audio_base = get_unit_base(unit);
650	if (!isight->audio_base) {
651		dev_err(&unit->device, "audio unit base not found\n");
652		err = -ENXIO;
653		goto err_unit;
654	}
655	fw_iso_resources_init(&isight->resources, unit);
656
657	card->private_free = isight_card_free;
658
659	strcpy(card->driver, "iSight");
660	strcpy(card->shortname, "Apple iSight");
661	snprintf(card->longname, sizeof(card->longname),
662		 "Apple iSight (GUID %08x%08x) at %s, S%d",
663		 fw_dev->config_rom[3], fw_dev->config_rom[4],
664		 dev_name(&unit->device), 100 << fw_dev->max_speed);
665	strcpy(card->mixername, "iSight");
666
667	err = isight_create_pcm(isight);
668	if (err < 0)
669		goto error;
670
671	err = isight_create_mixer(isight);
672	if (err < 0)
673		goto error;
674
675	err = snd_card_register(card);
676	if (err < 0)
677		goto error;
678
679	dev_set_drvdata(unit_dev, isight);
680
681	return 0;
682
683err_unit:
684	fw_unit_put(isight->unit);
685	fw_device_put(isight->device);
686	mutex_destroy(&isight->mutex);
687error:
688	snd_card_free(card);
689	return err;
690}
691
692static int isight_remove(struct device *dev)
693{
694	struct isight *isight = dev_get_drvdata(dev);
 
 
 
 
 
 
 
 
 
 
 
 
 
695
696	isight_pcm_abort(isight);
697
698	snd_card_disconnect(isight->card);
699
700	mutex_lock(&isight->mutex);
701	isight_stop_streaming(isight);
702	mutex_unlock(&isight->mutex);
703
704	snd_card_free_when_closed(isight->card);
705
706	return 0;
707}
708
709static void isight_bus_reset(struct fw_unit *unit)
710{
711	struct isight *isight = dev_get_drvdata(&unit->device);
712
713	if (fw_iso_resources_update(&isight->resources) < 0) {
714		isight_pcm_abort(isight);
715
716		mutex_lock(&isight->mutex);
717		isight_stop_streaming(isight);
718		mutex_unlock(&isight->mutex);
719	}
720}
721
722static const struct ieee1394_device_id isight_id_table[] = {
723	{
724		.match_flags  = IEEE1394_MATCH_SPECIFIER_ID |
725				IEEE1394_MATCH_VERSION,
726		.specifier_id = OUI_APPLE,
727		.version      = SW_ISIGHT_AUDIO,
728	},
729	{ }
730};
731MODULE_DEVICE_TABLE(ieee1394, isight_id_table);
732
733static struct fw_driver isight_driver = {
734	.driver   = {
735		.owner	= THIS_MODULE,
736		.name	= KBUILD_MODNAME,
737		.bus	= &fw_bus_type,
738		.probe	= isight_probe,
739		.remove	= isight_remove,
740	},
 
741	.update   = isight_bus_reset,
 
742	.id_table = isight_id_table,
743};
744
745static int __init alsa_isight_init(void)
746{
747	return driver_register(&isight_driver.driver);
748}
749
750static void __exit alsa_isight_exit(void)
751{
752	driver_unregister(&isight_driver.driver);
753}
754
755module_init(alsa_isight_init);
756module_exit(alsa_isight_exit);