Add the rt linux 4.1.3-rt3 as base
[kvmfornfv.git] / kernel / sound / firewire / isight.c
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
49 struct 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
70 struct 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
78 MODULE_DESCRIPTION("iSight audio driver");
79 MODULE_AUTHOR("Clemens Ladisch <clemens@ladisch.de>");
80 MODULE_LICENSE("GPL v2");
81
82 static struct fw_iso_packet audio_packet = {
83         .payload_length = sizeof(struct audio_payload),
84         .interrupt = 1,
85         .header_length = 4,
86 };
87
88 static 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
108 static 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
132 static void isight_pcm_abort(struct isight *isight)
133 {
134         if (ACCESS_ONCE(isight->pcm_active))
135                 snd_pcm_stop_xrun(isight->pcm);
136 }
137
138 static void isight_dropped_samples(struct isight *isight, unsigned int total)
139 {
140         struct snd_pcm_runtime *runtime;
141         u32 dropped;
142         unsigned int count1;
143
144         if (!ACCESS_ONCE(isight->pcm_running))
145                 return;
146
147         runtime = isight->pcm->runtime;
148         dropped = total - isight->total_samples;
149         if (dropped < runtime->buffer_size) {
150                 if (isight->buffer_pointer + dropped <= runtime->buffer_size) {
151                         memset(runtime->dma_area + isight->buffer_pointer * 4,
152                                0, dropped * 4);
153                 } else {
154                         count1 = runtime->buffer_size - isight->buffer_pointer;
155                         memset(runtime->dma_area + isight->buffer_pointer * 4,
156                                0, count1 * 4);
157                         memset(runtime->dma_area, 0, (dropped - count1) * 4);
158                 }
159                 isight_update_pointers(isight, dropped);
160         } else {
161                 isight_pcm_abort(isight);
162         }
163 }
164
165 static void isight_packet(struct fw_iso_context *context, u32 cycle,
166                           size_t header_length, void *header, void *data)
167 {
168         struct isight *isight = data;
169         const struct audio_payload *payload;
170         unsigned int index, length, count, total;
171         int err;
172
173         if (isight->packet_index < 0)
174                 return;
175         index = isight->packet_index;
176         payload = isight->buffer.packets[index].buffer;
177         length = be32_to_cpup(header) >> 16;
178
179         if (likely(length >= 16 &&
180                    payload->signature == cpu_to_be32(0x73676874/*"sght"*/))) {
181                 count = be32_to_cpu(payload->sample_count);
182                 if (likely(count <= (length - 16) / 4)) {
183                         total = be32_to_cpu(payload->sample_total);
184                         if (unlikely(total != isight->total_samples)) {
185                                 if (!isight->first_packet)
186                                         isight_dropped_samples(isight, total);
187                                 isight->first_packet = false;
188                                 isight->total_samples = total;
189                         }
190
191                         isight_samples(isight, payload->samples, count);
192                         isight->total_samples += count;
193                 }
194         }
195
196         err = fw_iso_context_queue(isight->context, &audio_packet,
197                                    &isight->buffer.iso_buffer,
198                                    isight->buffer.packets[index].offset);
199         if (err < 0) {
200                 dev_err(&isight->unit->device, "queueing error: %d\n", err);
201                 isight_pcm_abort(isight);
202                 isight->packet_index = -1;
203                 return;
204         }
205         fw_iso_context_queue_flush(isight->context);
206
207         if (++index >= QUEUE_LENGTH)
208                 index = 0;
209         isight->packet_index = index;
210 }
211
212 static int isight_connect(struct isight *isight)
213 {
214         int ch, err;
215         __be32 value;
216
217 retry_after_bus_reset:
218         ch = fw_iso_resources_allocate(&isight->resources,
219                                        sizeof(struct audio_payload),
220                                        isight->device->max_speed);
221         if (ch < 0) {
222                 err = ch;
223                 goto error;
224         }
225
226         value = cpu_to_be32(ch | (isight->device->max_speed << SPEED_SHIFT));
227         err = snd_fw_transaction(isight->unit, TCODE_WRITE_QUADLET_REQUEST,
228                                  isight->audio_base + REG_ISO_TX_CONFIG,
229                                  &value, 4, FW_FIXED_GENERATION |
230                                  isight->resources.generation);
231         if (err == -EAGAIN) {
232                 fw_iso_resources_free(&isight->resources);
233                 goto retry_after_bus_reset;
234         } else if (err < 0) {
235                 goto err_resources;
236         }
237
238         return 0;
239
240 err_resources:
241         fw_iso_resources_free(&isight->resources);
242 error:
243         return err;
244 }
245
246 static int isight_open(struct snd_pcm_substream *substream)
247 {
248         static const struct snd_pcm_hardware hardware = {
249                 .info = SNDRV_PCM_INFO_MMAP |
250                         SNDRV_PCM_INFO_MMAP_VALID |
251                         SNDRV_PCM_INFO_BATCH |
252                         SNDRV_PCM_INFO_INTERLEAVED |
253                         SNDRV_PCM_INFO_BLOCK_TRANSFER,
254                 .formats = SNDRV_PCM_FMTBIT_S16_BE,
255                 .rates = SNDRV_PCM_RATE_48000,
256                 .rate_min = 48000,
257                 .rate_max = 48000,
258                 .channels_min = 2,
259                 .channels_max = 2,
260                 .buffer_bytes_max = 4 * 1024 * 1024,
261                 .period_bytes_min = MAX_FRAMES_PER_PACKET * 4,
262                 .period_bytes_max = 1024 * 1024,
263                 .periods_min = 2,
264                 .periods_max = UINT_MAX,
265         };
266         struct isight *isight = substream->private_data;
267
268         substream->runtime->hw = hardware;
269
270         return iso_packets_buffer_init(&isight->buffer, isight->unit,
271                                        QUEUE_LENGTH,
272                                        sizeof(struct audio_payload),
273                                        DMA_FROM_DEVICE);
274 }
275
276 static int isight_close(struct snd_pcm_substream *substream)
277 {
278         struct isight *isight = substream->private_data;
279
280         iso_packets_buffer_destroy(&isight->buffer, isight->unit);
281
282         return 0;
283 }
284
285 static int isight_hw_params(struct snd_pcm_substream *substream,
286                             struct snd_pcm_hw_params *hw_params)
287 {
288         struct isight *isight = substream->private_data;
289         int err;
290
291         err = snd_pcm_lib_alloc_vmalloc_buffer(substream,
292                                                params_buffer_bytes(hw_params));
293         if (err < 0)
294                 return err;
295
296         ACCESS_ONCE(isight->pcm_active) = true;
297
298         return 0;
299 }
300
301 static int reg_read(struct isight *isight, int offset, __be32 *value)
302 {
303         return snd_fw_transaction(isight->unit, TCODE_READ_QUADLET_REQUEST,
304                                   isight->audio_base + offset, value, 4, 0);
305 }
306
307 static int reg_write(struct isight *isight, int offset, __be32 value)
308 {
309         return snd_fw_transaction(isight->unit, TCODE_WRITE_QUADLET_REQUEST,
310                                   isight->audio_base + offset, &value, 4, 0);
311 }
312
313 static void isight_stop_streaming(struct isight *isight)
314 {
315         __be32 value;
316
317         if (!isight->context)
318                 return;
319
320         fw_iso_context_stop(isight->context);
321         fw_iso_context_destroy(isight->context);
322         isight->context = NULL;
323         fw_iso_resources_free(&isight->resources);
324         value = 0;
325         snd_fw_transaction(isight->unit, TCODE_WRITE_QUADLET_REQUEST,
326                            isight->audio_base + REG_AUDIO_ENABLE,
327                            &value, 4, FW_QUIET);
328 }
329
330 static int isight_hw_free(struct snd_pcm_substream *substream)
331 {
332         struct isight *isight = substream->private_data;
333
334         ACCESS_ONCE(isight->pcm_active) = false;
335
336         mutex_lock(&isight->mutex);
337         isight_stop_streaming(isight);
338         mutex_unlock(&isight->mutex);
339
340         return snd_pcm_lib_free_vmalloc_buffer(substream);
341 }
342
343 static int isight_start_streaming(struct isight *isight)
344 {
345         unsigned int i;
346         int err;
347
348         if (isight->context) {
349                 if (isight->packet_index < 0)
350                         isight_stop_streaming(isight);
351                 else
352                         return 0;
353         }
354
355         err = reg_write(isight, REG_SAMPLE_RATE, cpu_to_be32(RATE_48000));
356         if (err < 0)
357                 goto error;
358
359         err = isight_connect(isight);
360         if (err < 0)
361                 goto error;
362
363         err = reg_write(isight, REG_AUDIO_ENABLE, cpu_to_be32(AUDIO_ENABLE));
364         if (err < 0)
365                 goto err_resources;
366
367         isight->context = fw_iso_context_create(isight->device->card,
368                                                 FW_ISO_CONTEXT_RECEIVE,
369                                                 isight->resources.channel,
370                                                 isight->device->max_speed,
371                                                 4, isight_packet, isight);
372         if (IS_ERR(isight->context)) {
373                 err = PTR_ERR(isight->context);
374                 isight->context = NULL;
375                 goto err_resources;
376         }
377
378         for (i = 0; i < QUEUE_LENGTH; ++i) {
379                 err = fw_iso_context_queue(isight->context, &audio_packet,
380                                            &isight->buffer.iso_buffer,
381                                            isight->buffer.packets[i].offset);
382                 if (err < 0)
383                         goto err_context;
384         }
385
386         isight->first_packet = true;
387         isight->packet_index = 0;
388
389         err = fw_iso_context_start(isight->context, -1, 0,
390                                    FW_ISO_CONTEXT_MATCH_ALL_TAGS/*?*/);
391         if (err < 0)
392                 goto err_context;
393
394         return 0;
395
396 err_context:
397         fw_iso_context_destroy(isight->context);
398         isight->context = NULL;
399 err_resources:
400         fw_iso_resources_free(&isight->resources);
401         reg_write(isight, REG_AUDIO_ENABLE, 0);
402 error:
403         return err;
404 }
405
406 static int isight_prepare(struct snd_pcm_substream *substream)
407 {
408         struct isight *isight = substream->private_data;
409         int err;
410
411         isight->buffer_pointer = 0;
412         isight->period_counter = 0;
413
414         mutex_lock(&isight->mutex);
415         err = isight_start_streaming(isight);
416         mutex_unlock(&isight->mutex);
417
418         return err;
419 }
420
421 static int isight_trigger(struct snd_pcm_substream *substream, int cmd)
422 {
423         struct isight *isight = substream->private_data;
424
425         switch (cmd) {
426         case SNDRV_PCM_TRIGGER_START:
427                 ACCESS_ONCE(isight->pcm_running) = true;
428                 break;
429         case SNDRV_PCM_TRIGGER_STOP:
430                 ACCESS_ONCE(isight->pcm_running) = false;
431                 break;
432         default:
433                 return -EINVAL;
434         }
435         return 0;
436 }
437
438 static snd_pcm_uframes_t isight_pointer(struct snd_pcm_substream *substream)
439 {
440         struct isight *isight = substream->private_data;
441
442         return ACCESS_ONCE(isight->buffer_pointer);
443 }
444
445 static int isight_create_pcm(struct isight *isight)
446 {
447         static struct snd_pcm_ops ops = {
448                 .open      = isight_open,
449                 .close     = isight_close,
450                 .ioctl     = snd_pcm_lib_ioctl,
451                 .hw_params = isight_hw_params,
452                 .hw_free   = isight_hw_free,
453                 .prepare   = isight_prepare,
454                 .trigger   = isight_trigger,
455                 .pointer   = isight_pointer,
456                 .page      = snd_pcm_lib_get_vmalloc_page,
457                 .mmap      = snd_pcm_lib_mmap_vmalloc,
458         };
459         struct snd_pcm *pcm;
460         int err;
461
462         err = snd_pcm_new(isight->card, "iSight", 0, 0, 1, &pcm);
463         if (err < 0)
464                 return err;
465         pcm->private_data = isight;
466         strcpy(pcm->name, "iSight");
467         isight->pcm = pcm->streams[SNDRV_PCM_STREAM_CAPTURE].substream;
468         isight->pcm->ops = &ops;
469
470         return 0;
471 }
472
473 static int isight_gain_info(struct snd_kcontrol *ctl,
474                             struct snd_ctl_elem_info *info)
475 {
476         struct isight *isight = ctl->private_data;
477
478         info->type = SNDRV_CTL_ELEM_TYPE_INTEGER;
479         info->count = 1;
480         info->value.integer.min = isight->gain_min;
481         info->value.integer.max = isight->gain_max;
482
483         return 0;
484 }
485
486 static int isight_gain_get(struct snd_kcontrol *ctl,
487                            struct snd_ctl_elem_value *value)
488 {
489         struct isight *isight = ctl->private_data;
490         __be32 gain;
491         int err;
492
493         err = reg_read(isight, REG_GAIN, &gain);
494         if (err < 0)
495                 return err;
496
497         value->value.integer.value[0] = (s32)be32_to_cpu(gain);
498
499         return 0;
500 }
501
502 static int isight_gain_put(struct snd_kcontrol *ctl,
503                            struct snd_ctl_elem_value *value)
504 {
505         struct isight *isight = ctl->private_data;
506
507         if (value->value.integer.value[0] < isight->gain_min ||
508             value->value.integer.value[0] > isight->gain_max)
509                 return -EINVAL;
510
511         return reg_write(isight, REG_GAIN,
512                          cpu_to_be32(value->value.integer.value[0]));
513 }
514
515 static int isight_mute_get(struct snd_kcontrol *ctl,
516                            struct snd_ctl_elem_value *value)
517 {
518         struct isight *isight = ctl->private_data;
519         __be32 mute;
520         int err;
521
522         err = reg_read(isight, REG_MUTE, &mute);
523         if (err < 0)
524                 return err;
525
526         value->value.integer.value[0] = !mute;
527
528         return 0;
529 }
530
531 static int isight_mute_put(struct snd_kcontrol *ctl,
532                            struct snd_ctl_elem_value *value)
533 {
534         struct isight *isight = ctl->private_data;
535
536         return reg_write(isight, REG_MUTE,
537                          (__force __be32)!value->value.integer.value[0]);
538 }
539
540 static int isight_create_mixer(struct isight *isight)
541 {
542         static const struct snd_kcontrol_new gain_control = {
543                 .iface = SNDRV_CTL_ELEM_IFACE_MIXER,
544                 .name = "Mic Capture Volume",
545                 .access = SNDRV_CTL_ELEM_ACCESS_READWRITE |
546                           SNDRV_CTL_ELEM_ACCESS_TLV_READ,
547                 .info = isight_gain_info,
548                 .get = isight_gain_get,
549                 .put = isight_gain_put,
550         };
551         static const struct snd_kcontrol_new mute_control = {
552                 .iface = SNDRV_CTL_ELEM_IFACE_MIXER,
553                 .name = "Mic Capture Switch",
554                 .info = snd_ctl_boolean_mono_info,
555                 .get = isight_mute_get,
556                 .put = isight_mute_put,
557         };
558         __be32 value;
559         struct snd_kcontrol *ctl;
560         int err;
561
562         err = reg_read(isight, REG_GAIN_RAW_START, &value);
563         if (err < 0)
564                 return err;
565         isight->gain_min = be32_to_cpu(value);
566
567         err = reg_read(isight, REG_GAIN_RAW_END, &value);
568         if (err < 0)
569                 return err;
570         isight->gain_max = be32_to_cpu(value);
571
572         isight->gain_tlv[0] = SNDRV_CTL_TLVT_DB_MINMAX;
573         isight->gain_tlv[1] = 2 * sizeof(unsigned int);
574
575         err = reg_read(isight, REG_GAIN_DB_START, &value);
576         if (err < 0)
577                 return err;
578         isight->gain_tlv[2] = (s32)be32_to_cpu(value) * 100;
579
580         err = reg_read(isight, REG_GAIN_DB_END, &value);
581         if (err < 0)
582                 return err;
583         isight->gain_tlv[3] = (s32)be32_to_cpu(value) * 100;
584
585         ctl = snd_ctl_new1(&gain_control, isight);
586         if (ctl)
587                 ctl->tlv.p = isight->gain_tlv;
588         err = snd_ctl_add(isight->card, ctl);
589         if (err < 0)
590                 return err;
591
592         err = snd_ctl_add(isight->card, snd_ctl_new1(&mute_control, isight));
593         if (err < 0)
594                 return err;
595
596         return 0;
597 }
598
599 static void isight_card_free(struct snd_card *card)
600 {
601         struct isight *isight = card->private_data;
602
603         fw_iso_resources_destroy(&isight->resources);
604         fw_unit_put(isight->unit);
605         mutex_destroy(&isight->mutex);
606 }
607
608 static u64 get_unit_base(struct fw_unit *unit)
609 {
610         struct fw_csr_iterator i;
611         int key, value;
612
613         fw_csr_iterator_init(&i, unit->directory);
614         while (fw_csr_iterator_next(&i, &key, &value))
615                 if (key == CSR_OFFSET)
616                         return CSR_REGISTER_BASE + value * 4;
617         return 0;
618 }
619
620 static int isight_probe(struct fw_unit *unit,
621                         const struct ieee1394_device_id *id)
622 {
623         struct fw_device *fw_dev = fw_parent_device(unit);
624         struct snd_card *card;
625         struct isight *isight;
626         int err;
627
628         err = snd_card_new(&unit->device, -1, NULL, THIS_MODULE,
629                            sizeof(*isight), &card);
630         if (err < 0)
631                 return err;
632
633         isight = card->private_data;
634         isight->card = card;
635         mutex_init(&isight->mutex);
636         isight->unit = fw_unit_get(unit);
637         isight->device = fw_dev;
638         isight->audio_base = get_unit_base(unit);
639         if (!isight->audio_base) {
640                 dev_err(&unit->device, "audio unit base not found\n");
641                 err = -ENXIO;
642                 goto err_unit;
643         }
644         fw_iso_resources_init(&isight->resources, unit);
645
646         card->private_free = isight_card_free;
647
648         strcpy(card->driver, "iSight");
649         strcpy(card->shortname, "Apple iSight");
650         snprintf(card->longname, sizeof(card->longname),
651                  "Apple iSight (GUID %08x%08x) at %s, S%d",
652                  fw_dev->config_rom[3], fw_dev->config_rom[4],
653                  dev_name(&unit->device), 100 << fw_dev->max_speed);
654         strcpy(card->mixername, "iSight");
655
656         err = isight_create_pcm(isight);
657         if (err < 0)
658                 goto error;
659
660         err = isight_create_mixer(isight);
661         if (err < 0)
662                 goto error;
663
664         err = snd_card_register(card);
665         if (err < 0)
666                 goto error;
667
668         dev_set_drvdata(&unit->device, isight);
669
670         return 0;
671
672 err_unit:
673         fw_unit_put(isight->unit);
674         mutex_destroy(&isight->mutex);
675 error:
676         snd_card_free(card);
677         return err;
678 }
679
680 static void isight_bus_reset(struct fw_unit *unit)
681 {
682         struct isight *isight = dev_get_drvdata(&unit->device);
683
684         if (fw_iso_resources_update(&isight->resources) < 0) {
685                 isight_pcm_abort(isight);
686
687                 mutex_lock(&isight->mutex);
688                 isight_stop_streaming(isight);
689                 mutex_unlock(&isight->mutex);
690         }
691 }
692
693 static void isight_remove(struct fw_unit *unit)
694 {
695         struct isight *isight = dev_get_drvdata(&unit->device);
696
697         isight_pcm_abort(isight);
698
699         snd_card_disconnect(isight->card);
700
701         mutex_lock(&isight->mutex);
702         isight_stop_streaming(isight);
703         mutex_unlock(&isight->mutex);
704
705         snd_card_free_when_closed(isight->card);
706 }
707
708 static const struct ieee1394_device_id isight_id_table[] = {
709         {
710                 .match_flags  = IEEE1394_MATCH_SPECIFIER_ID |
711                                 IEEE1394_MATCH_VERSION,
712                 .specifier_id = OUI_APPLE,
713                 .version      = SW_ISIGHT_AUDIO,
714         },
715         { }
716 };
717 MODULE_DEVICE_TABLE(ieee1394, isight_id_table);
718
719 static struct fw_driver isight_driver = {
720         .driver   = {
721                 .owner  = THIS_MODULE,
722                 .name   = KBUILD_MODNAME,
723                 .bus    = &fw_bus_type,
724         },
725         .probe    = isight_probe,
726         .update   = isight_bus_reset,
727         .remove   = isight_remove,
728         .id_table = isight_id_table,
729 };
730
731 static int __init alsa_isight_init(void)
732 {
733         return driver_register(&isight_driver.driver);
734 }
735
736 static void __exit alsa_isight_exit(void)
737 {
738         driver_unregister(&isight_driver.driver);
739 }
740
741 module_init(alsa_isight_init);
742 module_exit(alsa_isight_exit);