1 // SPDX-License-Identifier: GPL-2.0+
2 //
3 // Empiatech em28x1 audio extension
4 //
5 // Copyright (C) 2006 Markus Rechberger <mrechberger@gmail.com>
6 //
7 // Copyright (C) 2007-2016 Mauro Carvalho Chehab
8 //	- Port to work with the in-kernel driver
9 //	- Cleanups, fixes, alsa-controls, etc.
10 //
11 // This driver is based on my previous au600 usb pstn audio driver
12 // and inherits all the copyrights
13 //
14 // This program is free software; you can redistribute it and/or modify
15 // it under the terms of the GNU General Public License as published by
16 // the Free Software Foundation; either version 2 of the License, or
17 // (at your option) any later version.
18 //
19 // This program is distributed in the hope that it will be useful,
20 // but WITHOUT ANY WARRANTY; without even the implied warranty of
21 // MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
22 // GNU General Public License for more details.
23 
24 #include "em28xx.h"
25 
26 #include <linux/kernel.h>
27 #include <linux/usb.h>
28 #include <linux/init.h>
29 #include <linux/sound.h>
30 #include <linux/spinlock.h>
31 #include <linux/soundcard.h>
32 #include <linux/slab.h>
33 #include <linux/module.h>
34 #include <sound/core.h>
35 #include <sound/pcm.h>
36 #include <sound/pcm_params.h>
37 #include <sound/info.h>
38 #include <sound/initval.h>
39 #include <sound/control.h>
40 #include <sound/tlv.h>
41 #include <sound/ac97_codec.h>
42 #include <media/v4l2-common.h>
43 
44 static int debug;
45 module_param(debug, int, 0644);
46 MODULE_PARM_DESC(debug, "activates debug info");
47 
48 #define EM28XX_MAX_AUDIO_BUFS		5
49 #define EM28XX_MIN_AUDIO_PACKETS	64
50 
51 #define dprintk(fmt, arg...) do {					\
52 	if (debug)						\
53 		dev_printk(KERN_DEBUG, &dev->intf->dev,			\
54 			   "video: %s: " fmt, __func__, ## arg);	\
55 } while (0)
56 
57 static int index[SNDRV_CARDS] = SNDRV_DEFAULT_IDX;
58 
59 static int em28xx_deinit_isoc_audio(struct em28xx *dev)
60 {
61 	int i;
62 
63 	dprintk("Stopping isoc\n");
64 	for (i = 0; i < dev->adev.num_urb; i++) {
65 		struct urb *urb = dev->adev.urb[i];
66 
67 		if (!irqs_disabled())
68 			usb_kill_urb(urb);
69 		else
70 			usb_unlink_urb(urb);
71 	}
72 
73 	return 0;
74 }
75 
76 static void em28xx_audio_isocirq(struct urb *urb)
77 {
78 	struct em28xx            *dev = urb->context;
79 	int                      i;
80 	unsigned int             oldptr;
81 	int                      period_elapsed = 0;
82 	int                      status;
83 	unsigned char            *cp;
84 	unsigned int             stride;
85 	struct snd_pcm_substream *substream;
86 	struct snd_pcm_runtime   *runtime;
87 
88 	if (dev->disconnected) {
89 		dprintk("device disconnected while streaming. URB status=%d.\n",
90 			urb->status);
91 		atomic_set(&dev->adev.stream_started, 0);
92 		return;
93 	}
94 
95 	switch (urb->status) {
96 	case 0:             /* success */
97 	case -ETIMEDOUT:    /* NAK */
98 		break;
99 	case -ECONNRESET:   /* kill */
100 	case -ENOENT:
101 	case -ESHUTDOWN:
102 		return;
103 	default:            /* error */
104 		dprintk("urb completion error %d.\n", urb->status);
105 		break;
106 	}
107 
108 	if (atomic_read(&dev->adev.stream_started) == 0)
109 		return;
110 
111 	if (dev->adev.capture_pcm_substream) {
112 		substream = dev->adev.capture_pcm_substream;
113 		runtime = substream->runtime;
114 		stride = runtime->frame_bits >> 3;
115 
116 		for (i = 0; i < urb->number_of_packets; i++) {
117 			unsigned long flags;
118 			int length =
119 			    urb->iso_frame_desc[i].actual_length / stride;
120 			cp = (unsigned char *)urb->transfer_buffer +
121 			    urb->iso_frame_desc[i].offset;
122 
123 			if (!length)
124 				continue;
125 
126 			oldptr = dev->adev.hwptr_done_capture;
127 			if (oldptr + length >= runtime->buffer_size) {
128 				unsigned int cnt =
129 				    runtime->buffer_size - oldptr;
130 				memcpy(runtime->dma_area + oldptr * stride, cp,
131 				       cnt * stride);
132 				memcpy(runtime->dma_area, cp + cnt * stride,
133 				       length * stride - cnt * stride);
134 			} else {
135 				memcpy(runtime->dma_area + oldptr * stride, cp,
136 				       length * stride);
137 			}
138 
139 			snd_pcm_stream_lock_irqsave(substream, flags);
140 
141 			dev->adev.hwptr_done_capture += length;
142 			if (dev->adev.hwptr_done_capture >=
143 			    runtime->buffer_size)
144 				dev->adev.hwptr_done_capture -=
145 				    runtime->buffer_size;
146 
147 			dev->adev.capture_transfer_done += length;
148 			if (dev->adev.capture_transfer_done >=
149 			    runtime->period_size) {
150 				dev->adev.capture_transfer_done -=
151 				    runtime->period_size;
152 				period_elapsed = 1;
153 			}
154 
155 			snd_pcm_stream_unlock_irqrestore(substream, flags);
156 		}
157 		if (period_elapsed)
158 			snd_pcm_period_elapsed(substream);
159 	}
160 	urb->status = 0;
161 
162 	status = usb_submit_urb(urb, GFP_ATOMIC);
163 	if (status < 0)
164 		dev_err(&dev->intf->dev,
165 			"resubmit of audio urb failed (error=%i)\n",
166 			status);
167 }
168 
169 static int em28xx_init_audio_isoc(struct em28xx *dev)
170 {
171 	int       i, err;
172 
173 	dprintk("Starting isoc transfers\n");
174 
175 	/* Start streaming */
176 	for (i = 0; i < dev->adev.num_urb; i++) {
177 		memset(dev->adev.transfer_buffer[i], 0x80,
178 		       dev->adev.urb[i]->transfer_buffer_length);
179 
180 		err = usb_submit_urb(dev->adev.urb[i], GFP_ATOMIC);
181 		if (err) {
182 			dev_err(&dev->intf->dev,
183 				"submit of audio urb failed (error=%i)\n",
184 				err);
185 			em28xx_deinit_isoc_audio(dev);
186 			atomic_set(&dev->adev.stream_started, 0);
187 			return err;
188 		}
189 	}
190 
191 	return 0;
192 }
193 
194 static const struct snd_pcm_hardware snd_em28xx_hw_capture = {
195 	.info = SNDRV_PCM_INFO_BLOCK_TRANSFER |
196 		SNDRV_PCM_INFO_MMAP           |
197 		SNDRV_PCM_INFO_INTERLEAVED    |
198 		SNDRV_PCM_INFO_BATCH	      |
199 		SNDRV_PCM_INFO_MMAP_VALID,
200 
201 	.formats = SNDRV_PCM_FMTBIT_S16_LE,
202 
203 	.rates = SNDRV_PCM_RATE_48000,
204 
205 	.rate_min = 48000,
206 	.rate_max = 48000,
207 	.channels_min = 2,
208 	.channels_max = 2,
209 	.buffer_bytes_max = 62720 * 8,	/* just about the value in usbaudio.c */
210 
211 	/*
212 	 * The period is 12.288 bytes. Allow a 10% of variation along its
213 	 * value, in order to avoid overruns/underruns due to some clock
214 	 * drift.
215 	 *
216 	 * FIXME: This period assumes 64 packets, and a 48000 PCM rate.
217 	 * Calculate it dynamically.
218 	 */
219 	.period_bytes_min = 11059,
220 	.period_bytes_max = 13516,
221 
222 	.periods_min = 2,
223 	.periods_max = 98,		/* 12544, */
224 };
225 
226 static int snd_em28xx_capture_open(struct snd_pcm_substream *substream)
227 {
228 	struct em28xx *dev = snd_pcm_substream_chip(substream);
229 	struct snd_pcm_runtime *runtime = substream->runtime;
230 	int nonblock, ret = 0;
231 
232 	if (!dev) {
233 		pr_err("em28xx-audio: BUG: em28xx can't find device struct. Can't proceed with open\n");
234 		return -ENODEV;
235 	}
236 
237 	if (dev->disconnected)
238 		return -ENODEV;
239 
240 	dprintk("opening device and trying to acquire exclusive lock\n");
241 
242 	nonblock = !!(substream->f_flags & O_NONBLOCK);
243 	if (nonblock) {
244 		if (!mutex_trylock(&dev->lock))
245 			return -EAGAIN;
246 	} else {
247 		mutex_lock(&dev->lock);
248 	}
249 
250 	runtime->hw = snd_em28xx_hw_capture;
251 
252 	if (dev->adev.users == 0) {
253 		if (!dev->alt || dev->is_audio_only) {
254 			struct usb_device *udev;
255 
256 			udev = interface_to_usbdev(dev->intf);
257 
258 			if (dev->is_audio_only)
259 				/* audio is on a separate interface */
260 				dev->alt = 1;
261 			else
262 				/* audio is on the same interface as video */
263 				dev->alt = 7;
264 				/*
265 				 * FIXME: The intention seems to be to select
266 				 * the alt setting with the largest
267 				 * wMaxPacketSize for the video endpoint.
268 				 * At least dev->alt should be used instead, but
269 				 * we should probably not touch it at all if it
270 				 * is already >0, because wMaxPacketSize of the
271 				 * audio endpoints seems to be the same for all.
272 				 */
273 			dprintk("changing alternate number on interface %d to %d\n",
274 				dev->ifnum, dev->alt);
275 			usb_set_interface(udev, dev->ifnum, dev->alt);
276 		}
277 
278 		/* Sets volume, mute, etc */
279 		dev->mute = 0;
280 		ret = em28xx_audio_analog_set(dev);
281 		if (ret < 0)
282 			goto err;
283 	}
284 
285 	kref_get(&dev->ref);
286 	dev->adev.users++;
287 	mutex_unlock(&dev->lock);
288 
289 	/* Dynamically adjust the period size */
290 	snd_pcm_hw_constraint_integer(runtime, SNDRV_PCM_HW_PARAM_PERIODS);
291 	snd_pcm_hw_constraint_minmax(runtime, SNDRV_PCM_HW_PARAM_PERIOD_BYTES,
292 				     dev->adev.period * 95 / 100,
293 				     dev->adev.period * 105 / 100);
294 
295 	dev->adev.capture_pcm_substream = substream;
296 
297 	return 0;
298 err:
299 	mutex_unlock(&dev->lock);
300 
301 	dev_err(&dev->intf->dev,
302 		"Error while configuring em28xx mixer\n");
303 	return ret;
304 }
305 
306 static int snd_em28xx_pcm_close(struct snd_pcm_substream *substream)
307 {
308 	struct em28xx *dev = snd_pcm_substream_chip(substream);
309 
310 	dprintk("closing device\n");
311 
312 	dev->mute = 1;
313 	mutex_lock(&dev->lock);
314 	dev->adev.users--;
315 	if (atomic_read(&dev->adev.stream_started) > 0) {
316 		atomic_set(&dev->adev.stream_started, 0);
317 		schedule_work(&dev->adev.wq_trigger);
318 	}
319 
320 	em28xx_audio_analog_set(dev);
321 	mutex_unlock(&dev->lock);
322 	kref_put(&dev->ref, em28xx_free_device);
323 
324 	return 0;
325 }
326 
327 static int snd_em28xx_prepare(struct snd_pcm_substream *substream)
328 {
329 	struct em28xx *dev = snd_pcm_substream_chip(substream);
330 
331 	if (dev->disconnected)
332 		return -ENODEV;
333 
334 	dev->adev.hwptr_done_capture = 0;
335 	dev->adev.capture_transfer_done = 0;
336 
337 	return 0;
338 }
339 
340 static void audio_trigger(struct work_struct *work)
341 {
342 	struct em28xx_audio *adev =
343 			    container_of(work, struct em28xx_audio, wq_trigger);
344 	struct em28xx *dev = container_of(adev, struct em28xx, adev);
345 
346 	if (atomic_read(&adev->stream_started)) {
347 		dprintk("starting capture");
348 		em28xx_init_audio_isoc(dev);
349 	} else {
350 		dprintk("stopping capture");
351 		em28xx_deinit_isoc_audio(dev);
352 	}
353 }
354 
355 static int snd_em28xx_capture_trigger(struct snd_pcm_substream *substream,
356 				      int cmd)
357 {
358 	struct em28xx *dev = snd_pcm_substream_chip(substream);
359 	int retval = 0;
360 
361 	if (dev->disconnected)
362 		return -ENODEV;
363 
364 	switch (cmd) {
365 	case SNDRV_PCM_TRIGGER_PAUSE_RELEASE:
366 	case SNDRV_PCM_TRIGGER_RESUME:
367 	case SNDRV_PCM_TRIGGER_START:
368 		atomic_set(&dev->adev.stream_started, 1);
369 		break;
370 	case SNDRV_PCM_TRIGGER_PAUSE_PUSH:
371 	case SNDRV_PCM_TRIGGER_SUSPEND:
372 	case SNDRV_PCM_TRIGGER_STOP:
373 		atomic_set(&dev->adev.stream_started, 0);
374 		break;
375 	default:
376 		retval = -EINVAL;
377 	}
378 	schedule_work(&dev->adev.wq_trigger);
379 	return retval;
380 }
381 
382 static snd_pcm_uframes_t snd_em28xx_capture_pointer(struct snd_pcm_substream
383 						    *substream)
384 {
385 	unsigned long flags;
386 	struct em28xx *dev;
387 	snd_pcm_uframes_t hwptr_done;
388 
389 	dev = snd_pcm_substream_chip(substream);
390 	if (dev->disconnected)
391 		return SNDRV_PCM_POS_XRUN;
392 
393 	spin_lock_irqsave(&dev->adev.slock, flags);
394 	hwptr_done = dev->adev.hwptr_done_capture;
395 	spin_unlock_irqrestore(&dev->adev.slock, flags);
396 
397 	return hwptr_done;
398 }
399 
400 /*
401  * AC97 volume control support
402  */
403 static int em28xx_vol_info(struct snd_kcontrol *kcontrol,
404 			   struct snd_ctl_elem_info *info)
405 {
406 	struct em28xx *dev = snd_kcontrol_chip(kcontrol);
407 
408 	if (dev->disconnected)
409 		return -ENODEV;
410 
411 	info->type = SNDRV_CTL_ELEM_TYPE_INTEGER;
412 	info->count = 2;
413 	info->value.integer.min = 0;
414 	info->value.integer.max = 0x1f;
415 
416 	return 0;
417 }
418 
419 static int em28xx_vol_put(struct snd_kcontrol *kcontrol,
420 			  struct snd_ctl_elem_value *value)
421 {
422 	struct em28xx *dev = snd_kcontrol_chip(kcontrol);
423 	struct snd_pcm_substream *substream = dev->adev.capture_pcm_substream;
424 	u16 val = (0x1f - (value->value.integer.value[0] & 0x1f)) |
425 		  (0x1f - (value->value.integer.value[1] & 0x1f)) << 8;
426 	int nonblock = 0;
427 	int rc;
428 
429 	if (dev->disconnected)
430 		return -ENODEV;
431 
432 	if (substream)
433 		nonblock = !!(substream->f_flags & O_NONBLOCK);
434 	if (nonblock) {
435 		if (!mutex_trylock(&dev->lock))
436 			return -EAGAIN;
437 	} else {
438 		mutex_lock(&dev->lock);
439 	}
440 	rc = em28xx_read_ac97(dev, kcontrol->private_value);
441 	if (rc < 0)
442 		goto err;
443 
444 	val |= rc & 0x8000;	/* Preserve the mute flag */
445 
446 	rc = em28xx_write_ac97(dev, kcontrol->private_value, val);
447 	if (rc < 0)
448 		goto err;
449 
450 	dprintk("%sleft vol %d, right vol %d (0x%04x) to ac97 volume control 0x%04x\n",
451 		(val & 0x8000) ? "muted " : "",
452 		0x1f - ((val >> 8) & 0x1f), 0x1f - (val & 0x1f),
453 		val, (int)kcontrol->private_value);
454 
455 err:
456 	mutex_unlock(&dev->lock);
457 	return rc;
458 }
459 
460 static int em28xx_vol_get(struct snd_kcontrol *kcontrol,
461 			  struct snd_ctl_elem_value *value)
462 {
463 	struct em28xx *dev = snd_kcontrol_chip(kcontrol);
464 	struct snd_pcm_substream *substream = dev->adev.capture_pcm_substream;
465 	int nonblock = 0;
466 	int val;
467 
468 	if (dev->disconnected)
469 		return -ENODEV;
470 
471 	if (substream)
472 		nonblock = !!(substream->f_flags & O_NONBLOCK);
473 	if (nonblock) {
474 		if (!mutex_trylock(&dev->lock))
475 			return -EAGAIN;
476 	} else {
477 		mutex_lock(&dev->lock);
478 	}
479 	val = em28xx_read_ac97(dev, kcontrol->private_value);
480 	mutex_unlock(&dev->lock);
481 	if (val < 0)
482 		return val;
483 
484 	dprintk("%sleft vol %d, right vol %d (0x%04x) from ac97 volume control 0x%04x\n",
485 		(val & 0x8000) ? "muted " : "",
486 		0x1f - ((val >> 8) & 0x1f), 0x1f - (val & 0x1f),
487 		val, (int)kcontrol->private_value);
488 
489 	value->value.integer.value[0] = 0x1f - (val & 0x1f);
490 	value->value.integer.value[1] = 0x1f - ((val >> 8) & 0x1f);
491 
492 	return 0;
493 }
494 
495 static int em28xx_vol_put_mute(struct snd_kcontrol *kcontrol,
496 			       struct snd_ctl_elem_value *value)
497 {
498 	struct em28xx *dev = snd_kcontrol_chip(kcontrol);
499 	u16 val = value->value.integer.value[0];
500 	struct snd_pcm_substream *substream = dev->adev.capture_pcm_substream;
501 	int nonblock = 0;
502 	int rc;
503 
504 	if (dev->disconnected)
505 		return -ENODEV;
506 
507 	if (substream)
508 		nonblock = !!(substream->f_flags & O_NONBLOCK);
509 	if (nonblock) {
510 		if (!mutex_trylock(&dev->lock))
511 			return -EAGAIN;
512 	} else {
513 		mutex_lock(&dev->lock);
514 	}
515 	rc = em28xx_read_ac97(dev, kcontrol->private_value);
516 	if (rc < 0)
517 		goto err;
518 
519 	if (val)
520 		rc &= 0x1f1f;
521 	else
522 		rc |= 0x8000;
523 
524 	rc = em28xx_write_ac97(dev, kcontrol->private_value, rc);
525 	if (rc < 0)
526 		goto err;
527 
528 	dprintk("%sleft vol %d, right vol %d (0x%04x) to ac97 volume control 0x%04x\n",
529 		(val & 0x8000) ? "muted " : "",
530 		0x1f - ((val >> 8) & 0x1f), 0x1f - (val & 0x1f),
531 		val, (int)kcontrol->private_value);
532 
533 err:
534 	mutex_unlock(&dev->lock);
535 	return rc;
536 }
537 
538 static int em28xx_vol_get_mute(struct snd_kcontrol *kcontrol,
539 			       struct snd_ctl_elem_value *value)
540 {
541 	struct em28xx *dev = snd_kcontrol_chip(kcontrol);
542 	struct snd_pcm_substream *substream = dev->adev.capture_pcm_substream;
543 	int nonblock = 0;
544 	int val;
545 
546 	if (dev->disconnected)
547 		return -ENODEV;
548 
549 	if (substream)
550 		nonblock = !!(substream->f_flags & O_NONBLOCK);
551 	if (nonblock) {
552 		if (!mutex_trylock(&dev->lock))
553 			return -EAGAIN;
554 	} else {
555 		mutex_lock(&dev->lock);
556 	}
557 	val = em28xx_read_ac97(dev, kcontrol->private_value);
558 	mutex_unlock(&dev->lock);
559 	if (val < 0)
560 		return val;
561 
562 	if (val & 0x8000)
563 		value->value.integer.value[0] = 0;
564 	else
565 		value->value.integer.value[0] = 1;
566 
567 	dprintk("%sleft vol %d, right vol %d (0x%04x) from ac97 volume control 0x%04x\n",
568 		(val & 0x8000) ? "muted " : "",
569 		0x1f - ((val >> 8) & 0x1f), 0x1f - (val & 0x1f),
570 		val, (int)kcontrol->private_value);
571 
572 	return 0;
573 }
574 
575 static const DECLARE_TLV_DB_SCALE(em28xx_db_scale, -3450, 150, 0);
576 
577 static int em28xx_cvol_new(struct snd_card *card, struct em28xx *dev,
578 			   char *name, int id)
579 {
580 	int err;
581 	char ctl_name[44];
582 	struct snd_kcontrol *kctl;
583 	struct snd_kcontrol_new tmp;
584 
585 	memset(&tmp, 0, sizeof(tmp));
586 	tmp.iface = SNDRV_CTL_ELEM_IFACE_MIXER,
587 	tmp.private_value = id,
588 	tmp.name  = ctl_name,
589 
590 	/* Add Mute Control */
591 	sprintf(ctl_name, "%s Switch", name);
592 	tmp.get  = em28xx_vol_get_mute;
593 	tmp.put  = em28xx_vol_put_mute;
594 	tmp.info = snd_ctl_boolean_mono_info;
595 	kctl = snd_ctl_new1(&tmp, dev);
596 	err = snd_ctl_add(card, kctl);
597 	if (err < 0)
598 		return err;
599 	dprintk("Added control %s for ac97 volume control 0x%04x\n",
600 		ctl_name, id);
601 
602 	memset(&tmp, 0, sizeof(tmp));
603 	tmp.iface = SNDRV_CTL_ELEM_IFACE_MIXER,
604 	tmp.private_value = id,
605 	tmp.name  = ctl_name,
606 
607 	/* Add Volume Control */
608 	sprintf(ctl_name, "%s Volume", name);
609 	tmp.get   = em28xx_vol_get;
610 	tmp.put   = em28xx_vol_put;
611 	tmp.info  = em28xx_vol_info;
612 	tmp.tlv.p = em28xx_db_scale,
613 	kctl = snd_ctl_new1(&tmp, dev);
614 	err = snd_ctl_add(card, kctl);
615 	if (err < 0)
616 		return err;
617 	dprintk("Added control %s for ac97 volume control 0x%04x\n",
618 		ctl_name, id);
619 
620 	return 0;
621 }
622 
623 /*
624  * register/unregister code and data
625  */
626 static const struct snd_pcm_ops snd_em28xx_pcm_capture = {
627 	.open      = snd_em28xx_capture_open,
628 	.close     = snd_em28xx_pcm_close,
629 	.prepare   = snd_em28xx_prepare,
630 	.trigger   = snd_em28xx_capture_trigger,
631 	.pointer   = snd_em28xx_capture_pointer,
632 };
633 
634 static void em28xx_audio_free_urb(struct em28xx *dev)
635 {
636 	struct usb_device *udev = interface_to_usbdev(dev->intf);
637 	int i;
638 
639 	for (i = 0; i < dev->adev.num_urb; i++) {
640 		struct urb *urb = dev->adev.urb[i];
641 
642 		if (!urb)
643 			continue;
644 
645 		usb_free_coherent(udev, urb->transfer_buffer_length,
646 				  dev->adev.transfer_buffer[i],
647 				  urb->transfer_dma);
648 
649 		usb_free_urb(urb);
650 	}
651 	kfree(dev->adev.urb);
652 	kfree(dev->adev.transfer_buffer);
653 	dev->adev.num_urb = 0;
654 }
655 
656 /* high bandwidth multiplier, as encoded in highspeed endpoint descriptors */
657 static int em28xx_audio_ep_packet_size(struct usb_device *udev,
658 				       struct usb_endpoint_descriptor *e)
659 {
660 	int size = le16_to_cpu(e->wMaxPacketSize);
661 
662 	if (udev->speed == USB_SPEED_HIGH)
663 		return (size & 0x7ff) *  (1 + (((size) >> 11) & 0x03));
664 
665 	return size & 0x7ff;
666 }
667 
668 static int em28xx_audio_urb_init(struct em28xx *dev)
669 {
670 	struct usb_interface *intf;
671 	struct usb_endpoint_descriptor *e, *ep = NULL;
672 	struct usb_device *udev = interface_to_usbdev(dev->intf);
673 	int                 i, ep_size, interval, num_urb, npackets;
674 	int		    urb_size, bytes_per_transfer;
675 	u8 alt;
676 
677 	if (dev->ifnum)
678 		alt = 1;
679 	else
680 		alt = 7;
681 
682 	intf = usb_ifnum_to_if(udev, dev->ifnum);
683 
684 	if (intf->num_altsetting <= alt) {
685 		dev_err(&dev->intf->dev, "alt %d doesn't exist on interface %d\n",
686 			dev->ifnum, alt);
687 		return -ENODEV;
688 	}
689 
690 	for (i = 0; i < intf->altsetting[alt].desc.bNumEndpoints; i++) {
691 		e = &intf->altsetting[alt].endpoint[i].desc;
692 		if (!usb_endpoint_dir_in(e))
693 			continue;
694 		if (e->bEndpointAddress == EM28XX_EP_AUDIO) {
695 			ep = e;
696 			break;
697 		}
698 	}
699 
700 	if (!ep) {
701 		dev_err(&dev->intf->dev, "Couldn't find an audio endpoint");
702 		return -ENODEV;
703 	}
704 
705 	ep_size = em28xx_audio_ep_packet_size(udev, ep);
706 	interval = 1 << (ep->bInterval - 1);
707 
708 	dev_info(&dev->intf->dev,
709 		 "Endpoint 0x%02x %s on intf %d alt %d interval = %d, size %d\n",
710 		 EM28XX_EP_AUDIO, usb_speed_string(udev->speed),
711 		 dev->ifnum, alt, interval, ep_size);
712 
713 	/* Calculate the number and size of URBs to better fit the audio samples */
714 
715 	/*
716 	 * Estimate the number of bytes per DMA transfer.
717 	 *
718 	 * This is given by the bit rate (for now, only 48000 Hz) multiplied
719 	 * by 2 channels and 2 bytes/sample divided by the number of microframe
720 	 * intervals and by the microframe rate (125 us)
721 	 */
722 	bytes_per_transfer = DIV_ROUND_UP(48000 * 2 * 2, 125 * interval);
723 
724 	/*
725 	 * Estimate the number of transfer URBs. Don't let it go past the
726 	 * maximum number of URBs that is known to be supported by the device.
727 	 */
728 	num_urb = DIV_ROUND_UP(bytes_per_transfer, ep_size);
729 	if (num_urb > EM28XX_MAX_AUDIO_BUFS)
730 		num_urb = EM28XX_MAX_AUDIO_BUFS;
731 
732 	/*
733 	 * Now that we know the number of bytes per transfer and the number of
734 	 * URBs, estimate the typical size of an URB, in order to adjust the
735 	 * minimal number of packets.
736 	 */
737 	urb_size = bytes_per_transfer / num_urb;
738 
739 	/*
740 	 * Now, calculate the amount of audio packets to be filled on each
741 	 * URB. In order to preserve the old behaviour, use a minimal
742 	 * threshold for this value.
743 	 */
744 	npackets = EM28XX_MIN_AUDIO_PACKETS;
745 	if (urb_size > ep_size * npackets)
746 		npackets = DIV_ROUND_UP(urb_size, ep_size);
747 
748 	dev_info(&dev->intf->dev,
749 		 "Number of URBs: %d, with %d packets and %d size\n",
750 		 num_urb, npackets, urb_size);
751 
752 	/* Estimate the bytes per period */
753 	dev->adev.period = urb_size * npackets;
754 
755 	/* Allocate space to store the number of URBs to be used */
756 
757 	dev->adev.transfer_buffer = kcalloc(num_urb,
758 					    sizeof(*dev->adev.transfer_buffer),
759 					    GFP_KERNEL);
760 	if (!dev->adev.transfer_buffer)
761 		return -ENOMEM;
762 
763 	dev->adev.urb = kcalloc(num_urb, sizeof(*dev->adev.urb), GFP_KERNEL);
764 	if (!dev->adev.urb) {
765 		kfree(dev->adev.transfer_buffer);
766 		return -ENOMEM;
767 	}
768 
769 	/* Alloc memory for each URB and for each transfer buffer */
770 	dev->adev.num_urb = num_urb;
771 	for (i = 0; i < num_urb; i++) {
772 		struct urb *urb;
773 		int j, k;
774 		void *buf;
775 
776 		urb = usb_alloc_urb(npackets, GFP_KERNEL);
777 		if (!urb) {
778 			em28xx_audio_free_urb(dev);
779 			return -ENOMEM;
780 		}
781 		dev->adev.urb[i] = urb;
782 
783 		buf = usb_alloc_coherent(udev, npackets * ep_size, GFP_KERNEL,
784 					 &urb->transfer_dma);
785 		if (!buf) {
786 			dev_err(&dev->intf->dev,
787 				"usb_alloc_coherent failed!\n");
788 			em28xx_audio_free_urb(dev);
789 			return -ENOMEM;
790 		}
791 		dev->adev.transfer_buffer[i] = buf;
792 
793 		urb->dev = udev;
794 		urb->context = dev;
795 		urb->pipe = usb_rcvisocpipe(udev, EM28XX_EP_AUDIO);
796 		urb->transfer_flags = URB_ISO_ASAP | URB_NO_TRANSFER_DMA_MAP;
797 		urb->transfer_buffer = buf;
798 		urb->interval = interval;
799 		urb->complete = em28xx_audio_isocirq;
800 		urb->number_of_packets = npackets;
801 		urb->transfer_buffer_length = ep_size * npackets;
802 
803 		for (j = k = 0; j < npackets; j++, k += ep_size) {
804 			urb->iso_frame_desc[j].offset = k;
805 			urb->iso_frame_desc[j].length = ep_size;
806 		}
807 	}
808 
809 	return 0;
810 }
811 
812 static int em28xx_audio_init(struct em28xx *dev)
813 {
814 	struct em28xx_audio *adev = &dev->adev;
815 	struct usb_device *udev = interface_to_usbdev(dev->intf);
816 	struct snd_pcm      *pcm;
817 	struct snd_card     *card;
818 	static int          devnr;
819 	int		    err;
820 
821 	if (dev->usb_audio_type != EM28XX_USB_AUDIO_VENDOR) {
822 		/*
823 		 * This device does not support the extension (in this case
824 		 * the device is expecting the snd-usb-audio module or
825 		 * doesn't have analog audio support at all)
826 		 */
827 		return 0;
828 	}
829 
830 	dev_info(&dev->intf->dev, "Binding audio extension\n");
831 
832 	kref_get(&dev->ref);
833 
834 	dev_info(&dev->intf->dev,
835 		 "em28xx-audio.c: Copyright (C) 2006 Markus Rechberger\n");
836 	dev_info(&dev->intf->dev,
837 		 "em28xx-audio.c: Copyright (C) 2007-2016 Mauro Carvalho Chehab\n");
838 
839 	err = snd_card_new(&dev->intf->dev, index[devnr], "Em28xx Audio",
840 			   THIS_MODULE, 0, &card);
841 	if (err < 0)
842 		return err;
843 
844 	spin_lock_init(&adev->slock);
845 	adev->sndcard = card;
846 	adev->udev = udev;
847 
848 	err = snd_pcm_new(card, "Em28xx Audio", 0, 0, 1, &pcm);
849 	if (err < 0)
850 		goto card_free;
851 
852 	snd_pcm_set_ops(pcm, SNDRV_PCM_STREAM_CAPTURE, &snd_em28xx_pcm_capture);
853 	snd_pcm_set_managed_buffer_all(pcm, SNDRV_DMA_TYPE_VMALLOC, NULL, 0, 0);
854 	pcm->info_flags = 0;
855 	pcm->private_data = dev;
856 	strscpy(pcm->name, "Empia 28xx Capture", sizeof(pcm->name));
857 
858 	strscpy(card->driver, "Em28xx-Audio", sizeof(card->driver));
859 	strscpy(card->shortname, "Em28xx Audio", sizeof(card->shortname));
860 	strscpy(card->longname, "Empia Em28xx Audio", sizeof(card->longname));
861 
862 	INIT_WORK(&adev->wq_trigger, audio_trigger);
863 
864 	if (dev->audio_mode.ac97 != EM28XX_NO_AC97) {
865 		em28xx_cvol_new(card, dev, "Video", AC97_VIDEO);
866 		em28xx_cvol_new(card, dev, "Line In", AC97_LINE);
867 		em28xx_cvol_new(card, dev, "Phone", AC97_PHONE);
868 		em28xx_cvol_new(card, dev, "Microphone", AC97_MIC);
869 		em28xx_cvol_new(card, dev, "CD", AC97_CD);
870 		em28xx_cvol_new(card, dev, "AUX", AC97_AUX);
871 		em28xx_cvol_new(card, dev, "PCM", AC97_PCM);
872 
873 		em28xx_cvol_new(card, dev, "Master", AC97_MASTER);
874 		em28xx_cvol_new(card, dev, "Line", AC97_HEADPHONE);
875 		em28xx_cvol_new(card, dev, "Mono", AC97_MASTER_MONO);
876 		em28xx_cvol_new(card, dev, "LFE", AC97_CENTER_LFE_MASTER);
877 		em28xx_cvol_new(card, dev, "Surround", AC97_SURROUND_MASTER);
878 	}
879 
880 	err = em28xx_audio_urb_init(dev);
881 	if (err)
882 		goto card_free;
883 
884 	err = snd_card_register(card);
885 	if (err < 0)
886 		goto urb_free;
887 
888 	dev_info(&dev->intf->dev, "Audio extension successfully initialized\n");
889 	return 0;
890 
891 urb_free:
892 	em28xx_audio_free_urb(dev);
893 
894 card_free:
895 	snd_card_free(card);
896 	adev->sndcard = NULL;
897 
898 	return err;
899 }
900 
901 static int em28xx_audio_fini(struct em28xx *dev)
902 {
903 	if (!dev)
904 		return 0;
905 
906 	if (dev->usb_audio_type != EM28XX_USB_AUDIO_VENDOR) {
907 		/*
908 		 * This device does not support the extension (in this case
909 		 * the device is expecting the snd-usb-audio module or
910 		 * doesn't have analog audio support at all)
911 		 */
912 		return 0;
913 	}
914 
915 	dev_info(&dev->intf->dev, "Closing audio extension\n");
916 
917 	if (dev->adev.sndcard) {
918 		snd_card_disconnect(dev->adev.sndcard);
919 		flush_work(&dev->adev.wq_trigger);
920 
921 		em28xx_audio_free_urb(dev);
922 
923 		snd_card_free(dev->adev.sndcard);
924 		dev->adev.sndcard = NULL;
925 	}
926 
927 	kref_put(&dev->ref, em28xx_free_device);
928 	return 0;
929 }
930 
931 static int em28xx_audio_suspend(struct em28xx *dev)
932 {
933 	if (!dev)
934 		return 0;
935 
936 	if (dev->usb_audio_type != EM28XX_USB_AUDIO_VENDOR)
937 		return 0;
938 
939 	dev_info(&dev->intf->dev, "Suspending audio extension\n");
940 	em28xx_deinit_isoc_audio(dev);
941 	atomic_set(&dev->adev.stream_started, 0);
942 	return 0;
943 }
944 
945 static int em28xx_audio_resume(struct em28xx *dev)
946 {
947 	if (!dev)
948 		return 0;
949 
950 	if (dev->usb_audio_type != EM28XX_USB_AUDIO_VENDOR)
951 		return 0;
952 
953 	dev_info(&dev->intf->dev, "Resuming audio extension\n");
954 	/* Nothing to do other than schedule_work() ?? */
955 	schedule_work(&dev->adev.wq_trigger);
956 	return 0;
957 }
958 
959 static struct em28xx_ops audio_ops = {
960 	.id   = EM28XX_AUDIO,
961 	.name = "Em28xx Audio Extension",
962 	.init = em28xx_audio_init,
963 	.fini = em28xx_audio_fini,
964 	.suspend = em28xx_audio_suspend,
965 	.resume = em28xx_audio_resume,
966 };
967 
968 static int __init em28xx_alsa_register(void)
969 {
970 	return em28xx_register_extension(&audio_ops);
971 }
972 
973 static void __exit em28xx_alsa_unregister(void)
974 {
975 	em28xx_unregister_extension(&audio_ops);
976 }
977 
978 MODULE_LICENSE("GPL v2");
979 MODULE_AUTHOR("Markus Rechberger <mrechberger@gmail.com>");
980 MODULE_AUTHOR("Mauro Carvalho Chehab");
981 MODULE_DESCRIPTION(DRIVER_DESC " - audio interface");
982 MODULE_VERSION(EM28XX_VERSION);
983 
984 module_init(em28xx_alsa_register);
985 module_exit(em28xx_alsa_unregister);
986