[2/2] sound/usb: Update ALSA driver to use media controller API
diff mbox

Message ID dd21d1282a85d620be1aae497b66ccb355e458ba.1431110739.git.shuahkh@osg.samsung.com
State New
Headers show

Commit Message

Shuah Khan May 8, 2015, 7:31 p.m. UTC
Change ALSA driver to use media controller API to share tuner
with DVB and V4L2 drivers that control AU0828 media device.
Media device is created based on a newly added field value
in the struct snd_usb_audio_quirk. Using this approach, the
media controller API usage can be added for a specific device.
In this patch, media controller API is enabled for AU0828 hw.
snd_usb_create_quirk() will check this new field, if set will
create a media device using media_device_get_dr() interface.
media_device_get_dr() will allocate a new media device device
resource or return an existing one if it exists. During probe,
media usb driver could have created the media device. It will
then register the media device if it isn't already registered.
Media device unregister is done from usb_audio_disconnect().

New fields to add support for media entity and links are
added to struct snd_usb_substream. A new media entity for
ALSA and a link from tuner entity to the newly registered
ALSA entity are created from snd_usb_init_substream() and
removed from free_substream(). The state is kept to indicate
if tuner is linked. This is to account for case when tuner
entity doesn't exist. Media pipeline gets started to mark
the tuner busy from snd_usb_substream_capture_trigger in
response to SNDRV_PCM_TRIGGER_START and pipeline is stopped
in response to SNDRV_PCM_TRIGGER_STOP. snd_usb_pcm_close()
stops pipeline to cover the case when SNDRV_PCM_TRIGGER_STOP
isn't issued. Pipeline start and stop are done only when
tuner_linked is set.

Tested with and without CONFIG_MEDIA_CONTROLLER enabled.
Tested tuner entity doesn't exist case as au0828 v4l2
driver is the one that will create the tuner when it gets
updated to use media controller API.

Signed-off-by: Shuah Khan <shuahkh@osg.samsung.com>
---
 sound/usb/card.c         |  5 +++++
 sound/usb/card.h         | 12 ++++++++++
 sound/usb/pcm.c          | 23 ++++++++++++++++++-
 sound/usb/quirks-table.h |  1 +
 sound/usb/quirks.c       | 58 +++++++++++++++++++++++++++++++++++++++++++++++-
 sound/usb/quirks.h       |  6 +++++
 sound/usb/stream.c       | 40 +++++++++++++++++++++++++++++++++
 sound/usb/usbaudio.h     |  1 +
 8 files changed, 144 insertions(+), 2 deletions(-)

Comments

Shuah Khan May 11, 2015, 4:09 p.m. UTC | #1
On 05/08/2015 10:51 PM, Eric Wong wrote:
> Shuah Khan <shuahkh@osg.samsung.com> wrote:
>> @@ -541,13 +591,19 @@ int snd_usb_create_quirk(struct snd_usb_audio *chip,
>>  		[QUIRK_AUDIO_ALIGN_TRANSFER] = create_align_transfer_quirk,
>>  		[QUIRK_AUDIO_STANDARD_MIXER] = create_standard_mixer_quirk,
>>  	};
>> +	int ret;
>>  
>> +	if (quirk->media_device) {
>> +		/* don't want to fail when media_device_init() doesn't work */
>> +		ret = media_device_init(iface);
>> +	}
>>  	if (quirk->type < QUIRK_TYPE_COUNT) {
>> -		return quirk_funcs[quirk->type](chip, iface, driver, quirk);
>> +		ret = quirk_funcs[quirk->type](chip, iface, driver, quirk);
>>  	} else {
>>  		usb_audio_err(chip, "invalid quirk type %d\n", quirk->type);
>>  		return -ENXIO;
>>  	}
>> +	return ret;
>>  }
> 
> What is the point of saving 'ret' of media_device_init if it'll
> only be clobbered or ignored for ENXIO?
> 

Agreed. There is no point in saving it.

thanks,
-- Shuah
Takashi Iwai May 27, 2015, 3:24 p.m. UTC | #2
At Fri,  8 May 2015 13:31:31 -0600,
Shuah Khan wrote:
> 
> Change ALSA driver to use media controller API to share tuner
> with DVB and V4L2 drivers that control AU0828 media device.
> Media device is created based on a newly added field value
> in the struct snd_usb_audio_quirk. Using this approach, the
> media controller API usage can be added for a specific device.
> In this patch, media controller API is enabled for AU0828 hw.
> snd_usb_create_quirk() will check this new field, if set will
> create a media device using media_device_get_dr() interface.
> media_device_get_dr() will allocate a new media device device
> resource or return an existing one if it exists. During probe,
> media usb driver could have created the media device. It will
> then register the media device if it isn't already registered.
> Media device unregister is done from usb_audio_disconnect().
> 
> New fields to add support for media entity and links are
> added to struct snd_usb_substream. A new media entity for
> ALSA and a link from tuner entity to the newly registered
> ALSA entity are created from snd_usb_init_substream() and
> removed from free_substream(). The state is kept to indicate
> if tuner is linked. This is to account for case when tuner
> entity doesn't exist. Media pipeline gets started to mark
> the tuner busy from snd_usb_substream_capture_trigger in
> response to SNDRV_PCM_TRIGGER_START and pipeline is stopped
> in response to SNDRV_PCM_TRIGGER_STOP. snd_usb_pcm_close()
> stops pipeline to cover the case when SNDRV_PCM_TRIGGER_STOP
> isn't issued. Pipeline start and stop are done only when
> tuner_linked is set.
> 
> Tested with and without CONFIG_MEDIA_CONTROLLER enabled.
> Tested tuner entity doesn't exist case as au0828 v4l2
> driver is the one that will create the tuner when it gets
> updated to use media controller API.

I guess it gets broken when CONFIG_MEDIA_SUPPORT=m while
CONFIG_SND*=y.  So, it should be compiled in only when the media
support is built-in or both sound and media are module, i.e.

#ifdef CONFIG_MEDIA_CONTROLLER
#if defined(CONFIG_MEDIA_SUPPORT) || \
    (defined(CONFIG_MEDIA_SUPPORT_MODULE) && defined(MODULE))
#define I_CAN_USE_MEDIA_CONTROLLER
#endif
#endif

> Signed-off-by: Shuah Khan <shuahkh@osg.samsung.com>
> ---
>  sound/usb/card.c         |  5 +++++
>  sound/usb/card.h         | 12 ++++++++++
>  sound/usb/pcm.c          | 23 ++++++++++++++++++-
>  sound/usb/quirks-table.h |  1 +
>  sound/usb/quirks.c       | 58 +++++++++++++++++++++++++++++++++++++++++++++++-
>  sound/usb/quirks.h       |  6 +++++
>  sound/usb/stream.c       | 40 +++++++++++++++++++++++++++++++++
>  sound/usb/usbaudio.h     |  1 +
>  8 files changed, 144 insertions(+), 2 deletions(-)
> 
> diff --git a/sound/usb/card.c b/sound/usb/card.c
> index 1fab977..587fc24 100644
> --- a/sound/usb/card.c
> +++ b/sound/usb/card.c
> @@ -621,6 +621,11 @@ static void usb_audio_disconnect(struct usb_interface *intf)
>  		}
>  	}
>  
> +	/* Nice to check quirk && quirk->media_device
> +	 * need some special handlings. Doesn't look like
> +	 * we have access to quirk here */
> +	media_device_delete(intf);

This should be called once, so better in if (!was_shutdown) block, I
guess.

Apart from that, yes, a good way to call an optional destructor for
quirks would be better.


>  	chip->num_interfaces--;
>  	if (chip->num_interfaces <= 0) {
>  		usb_chip[chip->index] = NULL;
> diff --git a/sound/usb/card.h b/sound/usb/card.h
> index ef580b4..477bdcd 100644
> --- a/sound/usb/card.h
> +++ b/sound/usb/card.h
> @@ -1,6 +1,11 @@
>  #ifndef __USBAUDIO_CARD_H
>  #define __USBAUDIO_CARD_H
>  
> +#ifdef CONFIG_MEDIA_CONTROLLER
> +#include <media/media-device.h>
> +#include <media/media-entity.h>
> +#endif
> +
>  #define MAX_NR_RATES	1024
>  #define MAX_PACKS	6		/* per URB */
>  #define MAX_PACKS_HS	(MAX_PACKS * 8)	/* in high speed mode */
> @@ -155,6 +160,13 @@ struct snd_usb_substream {
>  	} dsd_dop;
>  
>  	bool trigger_tstamp_pending_update; /* trigger timestamp being updated from initial estimate */
> +#ifdef CONFIG_MEDIA_CONTROLLER
> +	struct media_device *media_dev;
> +	struct media_entity media_entity;
> +	struct media_pad media_pads;
> +	struct media_pipeline media_pipe;
> +	bool   tuner_linked;
> +#endif

Maybe a slightly better idea is to allocate these in a new record and
stores the pointer in stream->media_ctl or whatever new field.
Then, a check like
	if (subs->tuner_linked)
can be replaced with
	if (subs->media_ctl)

The whole media-specific stuff can be gathered in a single file,
e.g. sound/usb/media.c, and there you can define the struct.


>  };
>  
>  struct snd_usb_stream {
> diff --git a/sound/usb/pcm.c b/sound/usb/pcm.c
> index b4ef410..c2a40a9 100644
> --- a/sound/usb/pcm.c
> +++ b/sound/usb/pcm.c
> @@ -1225,6 +1225,10 @@ static int snd_usb_pcm_close(struct snd_pcm_substream *substream, int direction)
>  
>  	subs->pcm_substream = NULL;
>  	snd_usb_autosuspend(subs->stream->chip);
> +#ifdef CONFIG_MEDIA_CONTROLLER
> +	if (subs->tuner_linked)
> +		media_entity_pipeline_stop(&subs->media_entity);
> +#endif

Let's define each of such call properly and drop ifdef at each place.


>  	return 0;
>  }
> @@ -1587,9 +1591,22 @@ static int snd_usb_substream_capture_trigger(struct snd_pcm_substream *substream
>  
>  	switch (cmd) {
>  	case SNDRV_PCM_TRIGGER_START:
> +#ifdef CONFIG_MEDIA_CONTROLLER
> +		if (subs->tuner_linked) {
> +			err = media_entity_pipeline_start(&subs->media_entity,
> +							  &subs->media_pipe);
> +			if (err)
> +				return err;
> +		}
> +#endif
>  		err = start_endpoints(subs, false);
> -		if (err < 0)
> +		if (err < 0) {
> +#ifdef CONFIG_MEDIA_CONTROLLER
> +			if (subs->tuner_linked)
> +				media_entity_pipeline_stop(&subs->media_entity);
> +#endif
>  			return err;
> +		}
>  
>  		subs->data_endpoint->retire_data_urb = retire_capture_urb;
>  		subs->running = 1;
> @@ -1597,6 +1614,10 @@ static int snd_usb_substream_capture_trigger(struct snd_pcm_substream *substream
>  	case SNDRV_PCM_TRIGGER_STOP:
>  		stop_endpoints(subs, false);
>  		subs->running = 0;
> +#ifdef CONFIG_MEDIA_CONTROLLER
> +		if (subs->tuner_linked)
> +			media_entity_pipeline_stop(&subs->media_entity);
> +#endif
>  		return 0;
>  	case SNDRV_PCM_TRIGGER_PAUSE_PUSH:
>  		subs->data_endpoint->retire_data_urb = NULL;
> diff --git a/sound/usb/quirks-table.h b/sound/usb/quirks-table.h
> index 2f6d3e9..51c544f 100644
> --- a/sound/usb/quirks-table.h
> +++ b/sound/usb/quirks-table.h
> @@ -2798,6 +2798,7 @@ YAMAHA_DEVICE(0x7010, "UB99"),
>  		.product_name = pname, \
>  		.ifnum = QUIRK_ANY_INTERFACE, \
>  		.type = QUIRK_AUDIO_ALIGN_TRANSFER, \
> +		.media_device = 1, \
>  	} \

I guess this could be implemented with QUIRK_COMPOSITE, too, without
adding a new field.  But it might result in too complex code.  Let's
judge it later.


>  }
>  
> diff --git a/sound/usb/quirks.c b/sound/usb/quirks.c
> index 7c5a701..468e10f 100644
> --- a/sound/usb/quirks.c
> +++ b/sound/usb/quirks.c
> @@ -503,6 +503,56 @@ static int create_standard_mixer_quirk(struct snd_usb_audio *chip,
>  	return snd_usb_create_mixer(chip, quirk->ifnum, 0);
>  }
>  
> +#ifdef CONFIG_MEDIA_CONTROLLER
> +static int media_device_init(struct usb_interface *iface)
> +{
> +	struct media_device *mdev;
> +	struct usb_device *usbdev = interface_to_usbdev(iface);
> +	int ret;
> +
> +	mdev = media_device_get_dr(&usbdev->dev);
> +	if (!mdev)
> +		return -ENOMEM;
> +	if (!media_devnode_is_registered(&mdev->devnode)) {
> +		/* register media device */
> +		mdev->dev = &usbdev->dev;
> +		if (usbdev->product)
> +			strlcpy(mdev->model, usbdev->product,
> +				sizeof(mdev->model));
> +		if (usbdev->serial)
> +			strlcpy(mdev->serial, usbdev->serial,
> +				sizeof(mdev->serial));
> +		strcpy(mdev->bus_info, usbdev->devpath);
> +		mdev->hw_revision = le16_to_cpu(usbdev->descriptor.bcdDevice);
> +		ret = media_device_register(mdev);
> +		if (ret) {
> +			dev_err(&usbdev->dev,
> +				"Couldn't create a media device. Error: %d\n",
> +				ret);
> +			return ret;
> +		}
> +	}
> +	dev_info(&usbdev->dev, "Created media device.\n");
> +	return 0;
> +}
> +
> +void media_device_delete(struct usb_interface *iface)
> +{
> +	struct media_device *mdev;
> +	struct usb_device *usbdev = interface_to_usbdev(iface);
> +
> +	mdev = media_device_find_dr(&usbdev->dev);
> +	if (mdev && media_devnode_is_registered(&mdev->devnode))
> +		media_device_unregister(mdev);
> +	dev_info(&usbdev->dev, "Deleted media device.\n");
> +}
> +#else
> +static inline int media_device_init(struct usb_interface *iface)
> +{
> +	return 0;
> +}
> +#endif

Let's move all these media specific code into the single place.


thanks,

Takashi

>  /*
>   * audio-interface quirks
>   *
> @@ -541,13 +591,19 @@ int snd_usb_create_quirk(struct snd_usb_audio *chip,
>  		[QUIRK_AUDIO_ALIGN_TRANSFER] = create_align_transfer_quirk,
>  		[QUIRK_AUDIO_STANDARD_MIXER] = create_standard_mixer_quirk,
>  	};
> +	int ret;
>  
> +	if (quirk->media_device) {
> +		/* don't want to fail when media_device_init() doesn't work */
> +		ret = media_device_init(iface);
> +	}
>  	if (quirk->type < QUIRK_TYPE_COUNT) {
> -		return quirk_funcs[quirk->type](chip, iface, driver, quirk);
> +		ret = quirk_funcs[quirk->type](chip, iface, driver, quirk);
>  	} else {
>  		usb_audio_err(chip, "invalid quirk type %d\n", quirk->type);
>  		return -ENXIO;
>  	}
> +	return ret;
>  }
>  
>  /*
> diff --git a/sound/usb/quirks.h b/sound/usb/quirks.h
> index 2cd71ed..7782f03 100644
> --- a/sound/usb/quirks.h
> +++ b/sound/usb/quirks.h
> @@ -40,4 +40,10 @@ u64 snd_usb_interface_dsd_format_quirks(struct snd_usb_audio *chip,
>  					struct audioformat *fp,
>  					unsigned int sample_bytes);
>  
> +#ifdef CONFIG_MEDIA_CONTROLLER
> +void media_device_delete(struct usb_interface *iface);
> +#else
> +static inline void media_device_delete(struct usb_interface *iface) {}
> +#endif
> +
>  #endif /* __USBAUDIO_QUIRKS_H */
> diff --git a/sound/usb/stream.c b/sound/usb/stream.c
> index 310a382..d19f870 100644
> --- a/sound/usb/stream.c
> +++ b/sound/usb/stream.c
> @@ -52,6 +52,17 @@ static void free_substream(struct snd_usb_substream *subs)
>  		kfree(fp);
>  	}
>  	kfree(subs->rate_list.list);
> +#ifdef CONFIG_MEDIA_CONTROLLER
> +	if (subs->media_dev) {
> +		subs->media_dev = NULL;
> +		subs->tuner_linked = 0;
> +		media_entity_remove_links(&subs->media_entity);
> +		media_device_unregister_entity(&subs->media_entity);
> +		media_entity_cleanup(&subs->media_entity);
> +		pr_info("free_substream(): tuner_linked = %d\n",
> +			subs->tuner_linked);
> +	}
> +#endif
>  }
>  
>  
> @@ -75,6 +86,34 @@ static void snd_usb_audio_pcm_free(struct snd_pcm *pcm)
>  	}
>  }
>  
> +static void media_stream_init(struct snd_usb_substream *subs)
> +{
> +#ifdef CONFIG_MEDIA_CONTROLLER
> +	struct media_entity *entity;
> +	int ret;
> +
> +	subs->media_dev = media_device_find_dr(&subs->dev->dev);
> +	if (!subs->media_dev)
> +		return;
> +	subs->media_entity.type = MEDIA_ENT_T_DEVNODE_ALSA;
> +	media_entity_init(&subs->media_entity, 1, &subs->media_pads, 0);
> +	media_device_register_entity(subs->media_dev, &subs->media_entity);
> +	media_device_for_each_entity(entity, subs->media_dev) {
> +		switch (entity->type) {
> +		case MEDIA_ENT_T_V4L2_SUBDEV_TUNER:
> +			ret = media_entity_create_link(entity, 0,
> +						 &subs->media_entity, 0,
> +						 MEDIA_LNK_FL_ENABLED);
> +			if (ret == 0)
> +				subs->tuner_linked = 1;
> +		break;
> +		}
> +	}
> +	pr_info("media_stream_init(): tuner_linked = %d\n",
> +		subs->tuner_linked);
> +#endif
> +}
> +
>  /*
>   * initialize the substream instance.
>   */
> @@ -104,6 +143,7 @@ static void snd_usb_init_substream(struct snd_usb_stream *as,
>  	subs->ep_num = fp->endpoint;
>  	if (fp->channels > subs->channels_max)
>  		subs->channels_max = fp->channels;
> +	media_stream_init(subs);
>  }
>  
>  /* kctl callbacks for usb-audio channel maps */
> diff --git a/sound/usb/usbaudio.h b/sound/usb/usbaudio.h
> index 91d0380..c2dbf1d 100644
> --- a/sound/usb/usbaudio.h
> +++ b/sound/usb/usbaudio.h
> @@ -108,6 +108,7 @@ struct snd_usb_audio_quirk {
>  	const char *product_name;
>  	int16_t ifnum;
>  	uint16_t type;
> +	bool media_device;
>  	const void *data;
>  };
>  
> -- 
> 2.1.4
>
Hans Verkuil May 29, 2015, 10:43 a.m. UTC | #3
Hi Shuah,

Here are some comments:

On 05/08/2015 09:31 PM, Shuah Khan wrote:
> Change ALSA driver to use media controller API to share tuner
> with DVB and V4L2 drivers that control AU0828 media device.
> Media device is created based on a newly added field value
> in the struct snd_usb_audio_quirk. Using this approach, the
> media controller API usage can be added for a specific device.
> In this patch, media controller API is enabled for AU0828 hw.
> snd_usb_create_quirk() will check this new field, if set will
> create a media device using media_device_get_dr() interface.
> media_device_get_dr() will allocate a new media device device
> resource or return an existing one if it exists. During probe,
> media usb driver could have created the media device. It will
> then register the media device if it isn't already registered.
> Media device unregister is done from usb_audio_disconnect().
> 
> New fields to add support for media entity and links are
> added to struct snd_usb_substream. A new media entity for
> ALSA and a link from tuner entity to the newly registered
> ALSA entity are created from snd_usb_init_substream() and
> removed from free_substream(). The state is kept to indicate
> if tuner is linked. This is to account for case when tuner
> entity doesn't exist. Media pipeline gets started to mark
> the tuner busy from snd_usb_substream_capture_trigger in
> response to SNDRV_PCM_TRIGGER_START and pipeline is stopped
> in response to SNDRV_PCM_TRIGGER_STOP. snd_usb_pcm_close()
> stops pipeline to cover the case when SNDRV_PCM_TRIGGER_STOP
> isn't issued. Pipeline start and stop are done only when
> tuner_linked is set.

What happens if you start streaming (TRIGGER START), stop, streaming
(TRIGGER_STOP) and close the pcm? Wouldn't media_entity_pipeline_stop()
be called twice? Or is that harmless?

> 
> Tested with and without CONFIG_MEDIA_CONTROLLER enabled.
> Tested tuner entity doesn't exist case as au0828 v4l2
> driver is the one that will create the tuner when it gets
> updated to use media controller API.
> 
> Signed-off-by: Shuah Khan <shuahkh@osg.samsung.com>
> ---
>  sound/usb/card.c         |  5 +++++
>  sound/usb/card.h         | 12 ++++++++++
>  sound/usb/pcm.c          | 23 ++++++++++++++++++-
>  sound/usb/quirks-table.h |  1 +
>  sound/usb/quirks.c       | 58 +++++++++++++++++++++++++++++++++++++++++++++++-
>  sound/usb/quirks.h       |  6 +++++
>  sound/usb/stream.c       | 40 +++++++++++++++++++++++++++++++++
>  sound/usb/usbaudio.h     |  1 +
>  8 files changed, 144 insertions(+), 2 deletions(-)
> 
> diff --git a/sound/usb/card.c b/sound/usb/card.c
> index 1fab977..587fc24 100644
> --- a/sound/usb/card.c
> +++ b/sound/usb/card.c
> @@ -621,6 +621,11 @@ static void usb_audio_disconnect(struct usb_interface *intf)
>  		}
>  	}
>  
> +	/* Nice to check quirk && quirk->media_device
> +	 * need some special handlings. Doesn't look like
> +	 * we have access to quirk here */
> +	media_device_delete(intf);
> +
>  	chip->num_interfaces--;
>  	if (chip->num_interfaces <= 0) {
>  		usb_chip[chip->index] = NULL;
> diff --git a/sound/usb/card.h b/sound/usb/card.h
> index ef580b4..477bdcd 100644
> --- a/sound/usb/card.h
> +++ b/sound/usb/card.h
> @@ -1,6 +1,11 @@
>  #ifndef __USBAUDIO_CARD_H
>  #define __USBAUDIO_CARD_H
>  
> +#ifdef CONFIG_MEDIA_CONTROLLER
> +#include <media/media-device.h>
> +#include <media/media-entity.h>
> +#endif
> +
>  #define MAX_NR_RATES	1024
>  #define MAX_PACKS	6		/* per URB */
>  #define MAX_PACKS_HS	(MAX_PACKS * 8)	/* in high speed mode */
> @@ -155,6 +160,13 @@ struct snd_usb_substream {
>  	} dsd_dop;
>  
>  	bool trigger_tstamp_pending_update; /* trigger timestamp being updated from initial estimate */
> +#ifdef CONFIG_MEDIA_CONTROLLER
> +	struct media_device *media_dev;
> +	struct media_entity media_entity;
> +	struct media_pad media_pads;
> +	struct media_pipeline media_pipe;
> +	bool   tuner_linked;
> +#endif
>  };
>  
>  struct snd_usb_stream {
> diff --git a/sound/usb/pcm.c b/sound/usb/pcm.c
> index b4ef410..c2a40a9 100644
> --- a/sound/usb/pcm.c
> +++ b/sound/usb/pcm.c
> @@ -1225,6 +1225,10 @@ static int snd_usb_pcm_close(struct snd_pcm_substream *substream, int direction)
>  
>  	subs->pcm_substream = NULL;
>  	snd_usb_autosuspend(subs->stream->chip);
> +#ifdef CONFIG_MEDIA_CONTROLLER
> +	if (subs->tuner_linked)
> +		media_entity_pipeline_stop(&subs->media_entity);
> +#endif
>  
>  	return 0;
>  }
> @@ -1587,9 +1591,22 @@ static int snd_usb_substream_capture_trigger(struct snd_pcm_substream *substream
>  
>  	switch (cmd) {
>  	case SNDRV_PCM_TRIGGER_START:
> +#ifdef CONFIG_MEDIA_CONTROLLER
> +		if (subs->tuner_linked) {
> +			err = media_entity_pipeline_start(&subs->media_entity,
> +							  &subs->media_pipe);
> +			if (err)
> +				return err;
> +		}
> +#endif
>  		err = start_endpoints(subs, false);
> -		if (err < 0)
> +		if (err < 0) {
> +#ifdef CONFIG_MEDIA_CONTROLLER
> +			if (subs->tuner_linked)
> +				media_entity_pipeline_stop(&subs->media_entity);
> +#endif
>  			return err;
> +		}
>  
>  		subs->data_endpoint->retire_data_urb = retire_capture_urb;
>  		subs->running = 1;
> @@ -1597,6 +1614,10 @@ static int snd_usb_substream_capture_trigger(struct snd_pcm_substream *substream
>  	case SNDRV_PCM_TRIGGER_STOP:
>  		stop_endpoints(subs, false);
>  		subs->running = 0;
> +#ifdef CONFIG_MEDIA_CONTROLLER
> +		if (subs->tuner_linked)
> +			media_entity_pipeline_stop(&subs->media_entity);
> +#endif
>  		return 0;
>  	case SNDRV_PCM_TRIGGER_PAUSE_PUSH:
>  		subs->data_endpoint->retire_data_urb = NULL;
> diff --git a/sound/usb/quirks-table.h b/sound/usb/quirks-table.h
> index 2f6d3e9..51c544f 100644
> --- a/sound/usb/quirks-table.h
> +++ b/sound/usb/quirks-table.h
> @@ -2798,6 +2798,7 @@ YAMAHA_DEVICE(0x7010, "UB99"),
>  		.product_name = pname, \
>  		.ifnum = QUIRK_ANY_INTERFACE, \
>  		.type = QUIRK_AUDIO_ALIGN_TRANSFER, \
> +		.media_device = 1, \
>  	} \
>  }
>  
> diff --git a/sound/usb/quirks.c b/sound/usb/quirks.c
> index 7c5a701..468e10f 100644
> --- a/sound/usb/quirks.c
> +++ b/sound/usb/quirks.c
> @@ -503,6 +503,56 @@ static int create_standard_mixer_quirk(struct snd_usb_audio *chip,
>  	return snd_usb_create_mixer(chip, quirk->ifnum, 0);
>  }
>  
> +#ifdef CONFIG_MEDIA_CONTROLLER
> +static int media_device_init(struct usb_interface *iface)
> +{
> +	struct media_device *mdev;
> +	struct usb_device *usbdev = interface_to_usbdev(iface);
> +	int ret;
> +
> +	mdev = media_device_get_dr(&usbdev->dev);
> +	if (!mdev)
> +		return -ENOMEM;
> +	if (!media_devnode_is_registered(&mdev->devnode)) {
> +		/* register media device */
> +		mdev->dev = &usbdev->dev;
> +		if (usbdev->product)
> +			strlcpy(mdev->model, usbdev->product,
> +				sizeof(mdev->model));
> +		if (usbdev->serial)
> +			strlcpy(mdev->serial, usbdev->serial,
> +				sizeof(mdev->serial));
> +		strcpy(mdev->bus_info, usbdev->devpath);
> +		mdev->hw_revision = le16_to_cpu(usbdev->descriptor.bcdDevice);
> +		ret = media_device_register(mdev);
> +		if (ret) {
> +			dev_err(&usbdev->dev,
> +				"Couldn't create a media device. Error: %d\n",
> +				ret);
> +			return ret;
> +		}
> +	}
> +	dev_info(&usbdev->dev, "Created media device.\n");
> +	return 0;
> +}
> +
> +void media_device_delete(struct usb_interface *iface)
> +{
> +	struct media_device *mdev;
> +	struct usb_device *usbdev = interface_to_usbdev(iface);
> +
> +	mdev = media_device_find_dr(&usbdev->dev);
> +	if (mdev && media_devnode_is_registered(&mdev->devnode))
> +		media_device_unregister(mdev);
> +	dev_info(&usbdev->dev, "Deleted media device.\n");
> +}
> +#else
> +static inline int media_device_init(struct usb_interface *iface)
> +{
> +	return 0;
> +}
> +#endif
> +
>  /*
>   * audio-interface quirks
>   *
> @@ -541,13 +591,19 @@ int snd_usb_create_quirk(struct snd_usb_audio *chip,
>  		[QUIRK_AUDIO_ALIGN_TRANSFER] = create_align_transfer_quirk,
>  		[QUIRK_AUDIO_STANDARD_MIXER] = create_standard_mixer_quirk,
>  	};
> +	int ret;
>  
> +	if (quirk->media_device) {
> +		/* don't want to fail when media_device_init() doesn't work */
> +		ret = media_device_init(iface);
> +	}
>  	if (quirk->type < QUIRK_TYPE_COUNT) {
> -		return quirk_funcs[quirk->type](chip, iface, driver, quirk);
> +		ret = quirk_funcs[quirk->type](chip, iface, driver, quirk);
>  	} else {
>  		usb_audio_err(chip, "invalid quirk type %d\n", quirk->type);
>  		return -ENXIO;
>  	}
> +	return ret;
>  }
>  
>  /*
> diff --git a/sound/usb/quirks.h b/sound/usb/quirks.h
> index 2cd71ed..7782f03 100644
> --- a/sound/usb/quirks.h
> +++ b/sound/usb/quirks.h
> @@ -40,4 +40,10 @@ u64 snd_usb_interface_dsd_format_quirks(struct snd_usb_audio *chip,
>  					struct audioformat *fp,
>  					unsigned int sample_bytes);
>  
> +#ifdef CONFIG_MEDIA_CONTROLLER
> +void media_device_delete(struct usb_interface *iface);
> +#else
> +static inline void media_device_delete(struct usb_interface *iface) {}
> +#endif
> +
>  #endif /* __USBAUDIO_QUIRKS_H */
> diff --git a/sound/usb/stream.c b/sound/usb/stream.c
> index 310a382..d19f870 100644
> --- a/sound/usb/stream.c
> +++ b/sound/usb/stream.c
> @@ -52,6 +52,17 @@ static void free_substream(struct snd_usb_substream *subs)
>  		kfree(fp);
>  	}
>  	kfree(subs->rate_list.list);
> +#ifdef CONFIG_MEDIA_CONTROLLER
> +	if (subs->media_dev) {
> +		subs->media_dev = NULL;
> +		subs->tuner_linked = 0;
> +		media_entity_remove_links(&subs->media_entity);
> +		media_device_unregister_entity(&subs->media_entity);
> +		media_entity_cleanup(&subs->media_entity);
> +		pr_info("free_substream(): tuner_linked = %d\n",
> +			subs->tuner_linked);
> +	}
> +#endif
>  }
>  
>  
> @@ -75,6 +86,34 @@ static void snd_usb_audio_pcm_free(struct snd_pcm *pcm)
>  	}
>  }
>  
> +static void media_stream_init(struct snd_usb_substream *subs)
> +{
> +#ifdef CONFIG_MEDIA_CONTROLLER
> +	struct media_entity *entity;
> +	int ret;
> +
> +	subs->media_dev = media_device_find_dr(&subs->dev->dev);
> +	if (!subs->media_dev)
> +		return;
> +	subs->media_entity.type = MEDIA_ENT_T_DEVNODE_ALSA;
> +	media_entity_init(&subs->media_entity, 1, &subs->media_pads, 0);
> +	media_device_register_entity(subs->media_dev, &subs->media_entity);
> +	media_device_for_each_entity(entity, subs->media_dev) {
> +		switch (entity->type) {
> +		case MEDIA_ENT_T_V4L2_SUBDEV_TUNER:
> +			ret = media_entity_create_link(entity, 0,
> +						 &subs->media_entity, 0,
> +						 MEDIA_LNK_FL_ENABLED);

I'm pretty sure this will change. It certainly will not work in all cases. There are
devices that have two tuners, one for radio, one for TV. Just just picking the first
one wouldn't be sufficient. However, this is something we will need to discuss as part
of the larger MC discussions. A property might help here.

That said, for now this is OK.

Regards,

	Hans

> +			if (ret == 0)
> +				subs->tuner_linked = 1;
> +		break;
> +		}
> +	}
> +	pr_info("media_stream_init(): tuner_linked = %d\n",
> +		subs->tuner_linked);
> +#endif
> +}
> +
>  /*
>   * initialize the substream instance.
>   */
> @@ -104,6 +143,7 @@ static void snd_usb_init_substream(struct snd_usb_stream *as,
>  	subs->ep_num = fp->endpoint;
>  	if (fp->channels > subs->channels_max)
>  		subs->channels_max = fp->channels;
> +	media_stream_init(subs);
>  }
>  
>  /* kctl callbacks for usb-audio channel maps */
> diff --git a/sound/usb/usbaudio.h b/sound/usb/usbaudio.h
> index 91d0380..c2dbf1d 100644
> --- a/sound/usb/usbaudio.h
> +++ b/sound/usb/usbaudio.h
> @@ -108,6 +108,7 @@ struct snd_usb_audio_quirk {
>  	const char *product_name;
>  	int16_t ifnum;
>  	uint16_t type;
> +	bool media_device;
>  	const void *data;
>  };
>  
>
Shuah Khan June 1, 2015, 3:51 p.m. UTC | #4
On 05/27/2015 09:24 AM, Takashi Iwai wrote:
> At Fri,  8 May 2015 13:31:31 -0600,
> Shuah Khan wrote:
>>
>> Change ALSA driver to use media controller API to share tuner
>> with DVB and V4L2 drivers that control AU0828 media device.
>> Media device is created based on a newly added field value
>> in the struct snd_usb_audio_quirk. Using this approach, the
>> media controller API usage can be added for a specific device.
>> In this patch, media controller API is enabled for AU0828 hw.
>> snd_usb_create_quirk() will check this new field, if set will
>> create a media device using media_device_get_dr() interface.
>> media_device_get_dr() will allocate a new media device device
>> resource or return an existing one if it exists. During probe,
>> media usb driver could have created the media device. It will
>> then register the media device if it isn't already registered.
>> Media device unregister is done from usb_audio_disconnect().
>>
>> New fields to add support for media entity and links are
>> added to struct snd_usb_substream. A new media entity for
>> ALSA and a link from tuner entity to the newly registered
>> ALSA entity are created from snd_usb_init_substream() and
>> removed from free_substream(). The state is kept to indicate
>> if tuner is linked. This is to account for case when tuner
>> entity doesn't exist. Media pipeline gets started to mark
>> the tuner busy from snd_usb_substream_capture_trigger in
>> response to SNDRV_PCM_TRIGGER_START and pipeline is stopped
>> in response to SNDRV_PCM_TRIGGER_STOP. snd_usb_pcm_close()
>> stops pipeline to cover the case when SNDRV_PCM_TRIGGER_STOP
>> isn't issued. Pipeline start and stop are done only when
>> tuner_linked is set.
>>
>> Tested with and without CONFIG_MEDIA_CONTROLLER enabled.
>> Tested tuner entity doesn't exist case as au0828 v4l2
>> driver is the one that will create the tuner when it gets
>> updated to use media controller API.
> 
> I guess it gets broken when CONFIG_MEDIA_SUPPORT=m while
> CONFIG_SND*=y.  So, it should be compiled in only when the media
> support is built-in or both sound and media are module, i.e.
> 
> #ifdef CONFIG_MEDIA_CONTROLLER
> #if defined(CONFIG_MEDIA_SUPPORT) || \
>     (defined(CONFIG_MEDIA_SUPPORT_MODULE) && defined(MODULE))
> #define I_CAN_USE_MEDIA_CONTROLLER
> #endif
> #endif
> 
>> Signed-off-by: Shuah Khan <shuahkh@osg.samsung.com>
>> ---
>>  sound/usb/card.c         |  5 +++++
>>  sound/usb/card.h         | 12 ++++++++++
>>  sound/usb/pcm.c          | 23 ++++++++++++++++++-
>>  sound/usb/quirks-table.h |  1 +
>>  sound/usb/quirks.c       | 58 +++++++++++++++++++++++++++++++++++++++++++++++-
>>  sound/usb/quirks.h       |  6 +++++
>>  sound/usb/stream.c       | 40 +++++++++++++++++++++++++++++++++
>>  sound/usb/usbaudio.h     |  1 +
>>  8 files changed, 144 insertions(+), 2 deletions(-)
>>
>> diff --git a/sound/usb/card.c b/sound/usb/card.c
>> index 1fab977..587fc24 100644
>> --- a/sound/usb/card.c
>> +++ b/sound/usb/card.c
>> @@ -621,6 +621,11 @@ static void usb_audio_disconnect(struct usb_interface *intf)
>>  		}
>>  	}
>>  
>> +	/* Nice to check quirk && quirk->media_device
>> +	 * need some special handlings. Doesn't look like
>> +	 * we have access to quirk here */
>> +	media_device_delete(intf);
> 
> This should be called once, so better in if (!was_shutdown) block, I
> guess.

Moved it under if (!was_shutdown) block.

> 
> Apart from that, yes, a good way to call an optional destructor for
> quirks would be better.

Maybe something to look into as an enhancement for quirk handling.

> 
> 
>>  	chip->num_interfaces--;
>>  	if (chip->num_interfaces <= 0) {
>>  		usb_chip[chip->index] = NULL;
>> diff --git a/sound/usb/card.h b/sound/usb/card.h
>> index ef580b4..477bdcd 100644
>> --- a/sound/usb/card.h
>> +++ b/sound/usb/card.h
>> @@ -1,6 +1,11 @@
>>  #ifndef __USBAUDIO_CARD_H
>>  #define __USBAUDIO_CARD_H
>>  
>> +#ifdef CONFIG_MEDIA_CONTROLLER
>> +#include <media/media-device.h>
>> +#include <media/media-entity.h>
>> +#endif
>> +
>>  #define MAX_NR_RATES	1024
>>  #define MAX_PACKS	6		/* per URB */
>>  #define MAX_PACKS_HS	(MAX_PACKS * 8)	/* in high speed mode */
>> @@ -155,6 +160,13 @@ struct snd_usb_substream {
>>  	} dsd_dop;
>>  
>>  	bool trigger_tstamp_pending_update; /* trigger timestamp being updated from initial estimate */
>> +#ifdef CONFIG_MEDIA_CONTROLLER
>> +	struct media_device *media_dev;
>> +	struct media_entity media_entity;
>> +	struct media_pad media_pads;
>> +	struct media_pipeline media_pipe;
>> +	bool   tuner_linked;
>> +#endif
> 
> Maybe a slightly better idea is to allocate these in a new record and
> stores the pointer in stream->media_ctl or whatever new field.
> Then, a check like
> 	if (subs->tuner_linked)
> can be replaced with
> 	if (subs->media_ctl)
> 
> The whole media-specific stuff can be gathered in a single file,
> e.g. sound/usb/media.c, and there you can define the struct.
> 
> 
>>  };
>>  
>>  struct snd_usb_stream {
>> diff --git a/sound/usb/pcm.c b/sound/usb/pcm.c
>> index b4ef410..c2a40a9 100644
>> --- a/sound/usb/pcm.c
>> +++ b/sound/usb/pcm.c
>> @@ -1225,6 +1225,10 @@ static int snd_usb_pcm_close(struct snd_pcm_substream *substream, int direction)
>>  
>>  	subs->pcm_substream = NULL;
>>  	snd_usb_autosuspend(subs->stream->chip);
>> +#ifdef CONFIG_MEDIA_CONTROLLER
>> +	if (subs->tuner_linked)
>> +		media_entity_pipeline_stop(&subs->media_entity);
>> +#endif
> 
> Let's define each of such call properly and drop ifdef at each place.
> 
> 
>>  	return 0;
>>  }
>> @@ -1587,9 +1591,22 @@ static int snd_usb_substream_capture_trigger(struct snd_pcm_substream *substream
>>  
>>  	switch (cmd) {
>>  	case SNDRV_PCM_TRIGGER_START:
>> +#ifdef CONFIG_MEDIA_CONTROLLER
>> +		if (subs->tuner_linked) {
>> +			err = media_entity_pipeline_start(&subs->media_entity,
>> +							  &subs->media_pipe);
>> +			if (err)
>> +				return err;
>> +		}
>> +#endif
>>  		err = start_endpoints(subs, false);
>> -		if (err < 0)
>> +		if (err < 0) {
>> +#ifdef CONFIG_MEDIA_CONTROLLER
>> +			if (subs->tuner_linked)
>> +				media_entity_pipeline_stop(&subs->media_entity);
>> +#endif
>>  			return err;
>> +		}
>>  
>>  		subs->data_endpoint->retire_data_urb = retire_capture_urb;
>>  		subs->running = 1;
>> @@ -1597,6 +1614,10 @@ static int snd_usb_substream_capture_trigger(struct snd_pcm_substream *substream
>>  	case SNDRV_PCM_TRIGGER_STOP:
>>  		stop_endpoints(subs, false);
>>  		subs->running = 0;
>> +#ifdef CONFIG_MEDIA_CONTROLLER
>> +		if (subs->tuner_linked)
>> +			media_entity_pipeline_stop(&subs->media_entity);
>> +#endif
>>  		return 0;
>>  	case SNDRV_PCM_TRIGGER_PAUSE_PUSH:
>>  		subs->data_endpoint->retire_data_urb = NULL;
>> diff --git a/sound/usb/quirks-table.h b/sound/usb/quirks-table.h
>> index 2f6d3e9..51c544f 100644
>> --- a/sound/usb/quirks-table.h
>> +++ b/sound/usb/quirks-table.h
>> @@ -2798,6 +2798,7 @@ YAMAHA_DEVICE(0x7010, "UB99"),
>>  		.product_name = pname, \
>>  		.ifnum = QUIRK_ANY_INTERFACE, \
>>  		.type = QUIRK_AUDIO_ALIGN_TRANSFER, \
>> +		.media_device = 1, \
>>  	} \
> 
> I guess this could be implemented with QUIRK_COMPOSITE, too, without
> adding a new field.  But it might result in too complex code.  Let's
> judge it later.
> 

I looked into this. Looks like there is one quirk type allowed
at this time. My initial thought was to make .type an array of
quirk types so a device could have multiple quirk types. I opted
to go with the simpler route to add a new field instead.

> 
>>  }
>>  
>> diff --git a/sound/usb/quirks.c b/sound/usb/quirks.c
>> index 7c5a701..468e10f 100644
>> --- a/sound/usb/quirks.c
>> +++ b/sound/usb/quirks.c
>> @@ -503,6 +503,56 @@ static int create_standard_mixer_quirk(struct snd_usb_audio *chip,
>>  	return snd_usb_create_mixer(chip, quirk->ifnum, 0);
>>  }
>>  
>> +#ifdef CONFIG_MEDIA_CONTROLLER
>> +static int media_device_init(struct usb_interface *iface)
>> +{
>> +	struct media_device *mdev;
>> +	struct usb_device *usbdev = interface_to_usbdev(iface);
>> +	int ret;
>> +
>> +	mdev = media_device_get_dr(&usbdev->dev);
>> +	if (!mdev)
>> +		return -ENOMEM;
>> +	if (!media_devnode_is_registered(&mdev->devnode)) {
>> +		/* register media device */
>> +		mdev->dev = &usbdev->dev;
>> +		if (usbdev->product)
>> +			strlcpy(mdev->model, usbdev->product,
>> +				sizeof(mdev->model));
>> +		if (usbdev->serial)
>> +			strlcpy(mdev->serial, usbdev->serial,
>> +				sizeof(mdev->serial));
>> +		strcpy(mdev->bus_info, usbdev->devpath);
>> +		mdev->hw_revision = le16_to_cpu(usbdev->descriptor.bcdDevice);
>> +		ret = media_device_register(mdev);
>> +		if (ret) {
>> +			dev_err(&usbdev->dev,
>> +				"Couldn't create a media device. Error: %d\n",
>> +				ret);
>> +			return ret;
>> +		}
>> +	}
>> +	dev_info(&usbdev->dev, "Created media device.\n");
>> +	return 0;
>> +}
>> +
>> +void media_device_delete(struct usb_interface *iface)
>> +{
>> +	struct media_device *mdev;
>> +	struct usb_device *usbdev = interface_to_usbdev(iface);
>> +
>> +	mdev = media_device_find_dr(&usbdev->dev);
>> +	if (mdev && media_devnode_is_registered(&mdev->devnode))
>> +		media_device_unregister(mdev);
>> +	dev_info(&usbdev->dev, "Deleted media device.\n");
>> +}
>> +#else
>> +static inline int media_device_init(struct usb_interface *iface)
>> +{
>> +	return 0;
>> +}
>> +#endif
> 
> Let's move all these media specific code into the single place.
> 

Moved all the media specific code into a new file. I will send
v2 that covers Hans's comments as well later on this week.

P.S: Entity part of the code needs updates once Property API
solidifies.

thanks,
-- Shuah

Patch
diff mbox

diff --git a/sound/usb/card.c b/sound/usb/card.c
index 1fab977..587fc24 100644
--- a/sound/usb/card.c
+++ b/sound/usb/card.c
@@ -621,6 +621,11 @@  static void usb_audio_disconnect(struct usb_interface *intf)
 		}
 	}
 
+	/* Nice to check quirk && quirk->media_device
+	 * need some special handlings. Doesn't look like
+	 * we have access to quirk here */
+	media_device_delete(intf);
+
 	chip->num_interfaces--;
 	if (chip->num_interfaces <= 0) {
 		usb_chip[chip->index] = NULL;
diff --git a/sound/usb/card.h b/sound/usb/card.h
index ef580b4..477bdcd 100644
--- a/sound/usb/card.h
+++ b/sound/usb/card.h
@@ -1,6 +1,11 @@ 
 #ifndef __USBAUDIO_CARD_H
 #define __USBAUDIO_CARD_H
 
+#ifdef CONFIG_MEDIA_CONTROLLER
+#include <media/media-device.h>
+#include <media/media-entity.h>
+#endif
+
 #define MAX_NR_RATES	1024
 #define MAX_PACKS	6		/* per URB */
 #define MAX_PACKS_HS	(MAX_PACKS * 8)	/* in high speed mode */
@@ -155,6 +160,13 @@  struct snd_usb_substream {
 	} dsd_dop;
 
 	bool trigger_tstamp_pending_update; /* trigger timestamp being updated from initial estimate */
+#ifdef CONFIG_MEDIA_CONTROLLER
+	struct media_device *media_dev;
+	struct media_entity media_entity;
+	struct media_pad media_pads;
+	struct media_pipeline media_pipe;
+	bool   tuner_linked;
+#endif
 };
 
 struct snd_usb_stream {
diff --git a/sound/usb/pcm.c b/sound/usb/pcm.c
index b4ef410..c2a40a9 100644
--- a/sound/usb/pcm.c
+++ b/sound/usb/pcm.c
@@ -1225,6 +1225,10 @@  static int snd_usb_pcm_close(struct snd_pcm_substream *substream, int direction)
 
 	subs->pcm_substream = NULL;
 	snd_usb_autosuspend(subs->stream->chip);
+#ifdef CONFIG_MEDIA_CONTROLLER
+	if (subs->tuner_linked)
+		media_entity_pipeline_stop(&subs->media_entity);
+#endif
 
 	return 0;
 }
@@ -1587,9 +1591,22 @@  static int snd_usb_substream_capture_trigger(struct snd_pcm_substream *substream
 
 	switch (cmd) {
 	case SNDRV_PCM_TRIGGER_START:
+#ifdef CONFIG_MEDIA_CONTROLLER
+		if (subs->tuner_linked) {
+			err = media_entity_pipeline_start(&subs->media_entity,
+							  &subs->media_pipe);
+			if (err)
+				return err;
+		}
+#endif
 		err = start_endpoints(subs, false);
-		if (err < 0)
+		if (err < 0) {
+#ifdef CONFIG_MEDIA_CONTROLLER
+			if (subs->tuner_linked)
+				media_entity_pipeline_stop(&subs->media_entity);
+#endif
 			return err;
+		}
 
 		subs->data_endpoint->retire_data_urb = retire_capture_urb;
 		subs->running = 1;
@@ -1597,6 +1614,10 @@  static int snd_usb_substream_capture_trigger(struct snd_pcm_substream *substream
 	case SNDRV_PCM_TRIGGER_STOP:
 		stop_endpoints(subs, false);
 		subs->running = 0;
+#ifdef CONFIG_MEDIA_CONTROLLER
+		if (subs->tuner_linked)
+			media_entity_pipeline_stop(&subs->media_entity);
+#endif
 		return 0;
 	case SNDRV_PCM_TRIGGER_PAUSE_PUSH:
 		subs->data_endpoint->retire_data_urb = NULL;
diff --git a/sound/usb/quirks-table.h b/sound/usb/quirks-table.h
index 2f6d3e9..51c544f 100644
--- a/sound/usb/quirks-table.h
+++ b/sound/usb/quirks-table.h
@@ -2798,6 +2798,7 @@  YAMAHA_DEVICE(0x7010, "UB99"),
 		.product_name = pname, \
 		.ifnum = QUIRK_ANY_INTERFACE, \
 		.type = QUIRK_AUDIO_ALIGN_TRANSFER, \
+		.media_device = 1, \
 	} \
 }
 
diff --git a/sound/usb/quirks.c b/sound/usb/quirks.c
index 7c5a701..468e10f 100644
--- a/sound/usb/quirks.c
+++ b/sound/usb/quirks.c
@@ -503,6 +503,56 @@  static int create_standard_mixer_quirk(struct snd_usb_audio *chip,
 	return snd_usb_create_mixer(chip, quirk->ifnum, 0);
 }
 
+#ifdef CONFIG_MEDIA_CONTROLLER
+static int media_device_init(struct usb_interface *iface)
+{
+	struct media_device *mdev;
+	struct usb_device *usbdev = interface_to_usbdev(iface);
+	int ret;
+
+	mdev = media_device_get_dr(&usbdev->dev);
+	if (!mdev)
+		return -ENOMEM;
+	if (!media_devnode_is_registered(&mdev->devnode)) {
+		/* register media device */
+		mdev->dev = &usbdev->dev;
+		if (usbdev->product)
+			strlcpy(mdev->model, usbdev->product,
+				sizeof(mdev->model));
+		if (usbdev->serial)
+			strlcpy(mdev->serial, usbdev->serial,
+				sizeof(mdev->serial));
+		strcpy(mdev->bus_info, usbdev->devpath);
+		mdev->hw_revision = le16_to_cpu(usbdev->descriptor.bcdDevice);
+		ret = media_device_register(mdev);
+		if (ret) {
+			dev_err(&usbdev->dev,
+				"Couldn't create a media device. Error: %d\n",
+				ret);
+			return ret;
+		}
+	}
+	dev_info(&usbdev->dev, "Created media device.\n");
+	return 0;
+}
+
+void media_device_delete(struct usb_interface *iface)
+{
+	struct media_device *mdev;
+	struct usb_device *usbdev = interface_to_usbdev(iface);
+
+	mdev = media_device_find_dr(&usbdev->dev);
+	if (mdev && media_devnode_is_registered(&mdev->devnode))
+		media_device_unregister(mdev);
+	dev_info(&usbdev->dev, "Deleted media device.\n");
+}
+#else
+static inline int media_device_init(struct usb_interface *iface)
+{
+	return 0;
+}
+#endif
+
 /*
  * audio-interface quirks
  *
@@ -541,13 +591,19 @@  int snd_usb_create_quirk(struct snd_usb_audio *chip,
 		[QUIRK_AUDIO_ALIGN_TRANSFER] = create_align_transfer_quirk,
 		[QUIRK_AUDIO_STANDARD_MIXER] = create_standard_mixer_quirk,
 	};
+	int ret;
 
+	if (quirk->media_device) {
+		/* don't want to fail when media_device_init() doesn't work */
+		ret = media_device_init(iface);
+	}
 	if (quirk->type < QUIRK_TYPE_COUNT) {
-		return quirk_funcs[quirk->type](chip, iface, driver, quirk);
+		ret = quirk_funcs[quirk->type](chip, iface, driver, quirk);
 	} else {
 		usb_audio_err(chip, "invalid quirk type %d\n", quirk->type);
 		return -ENXIO;
 	}
+	return ret;
 }
 
 /*
diff --git a/sound/usb/quirks.h b/sound/usb/quirks.h
index 2cd71ed..7782f03 100644
--- a/sound/usb/quirks.h
+++ b/sound/usb/quirks.h
@@ -40,4 +40,10 @@  u64 snd_usb_interface_dsd_format_quirks(struct snd_usb_audio *chip,
 					struct audioformat *fp,
 					unsigned int sample_bytes);
 
+#ifdef CONFIG_MEDIA_CONTROLLER
+void media_device_delete(struct usb_interface *iface);
+#else
+static inline void media_device_delete(struct usb_interface *iface) {}
+#endif
+
 #endif /* __USBAUDIO_QUIRKS_H */
diff --git a/sound/usb/stream.c b/sound/usb/stream.c
index 310a382..d19f870 100644
--- a/sound/usb/stream.c
+++ b/sound/usb/stream.c
@@ -52,6 +52,17 @@  static void free_substream(struct snd_usb_substream *subs)
 		kfree(fp);
 	}
 	kfree(subs->rate_list.list);
+#ifdef CONFIG_MEDIA_CONTROLLER
+	if (subs->media_dev) {
+		subs->media_dev = NULL;
+		subs->tuner_linked = 0;
+		media_entity_remove_links(&subs->media_entity);
+		media_device_unregister_entity(&subs->media_entity);
+		media_entity_cleanup(&subs->media_entity);
+		pr_info("free_substream(): tuner_linked = %d\n",
+			subs->tuner_linked);
+	}
+#endif
 }
 
 
@@ -75,6 +86,34 @@  static void snd_usb_audio_pcm_free(struct snd_pcm *pcm)
 	}
 }
 
+static void media_stream_init(struct snd_usb_substream *subs)
+{
+#ifdef CONFIG_MEDIA_CONTROLLER
+	struct media_entity *entity;
+	int ret;
+
+	subs->media_dev = media_device_find_dr(&subs->dev->dev);
+	if (!subs->media_dev)
+		return;
+	subs->media_entity.type = MEDIA_ENT_T_DEVNODE_ALSA;
+	media_entity_init(&subs->media_entity, 1, &subs->media_pads, 0);
+	media_device_register_entity(subs->media_dev, &subs->media_entity);
+	media_device_for_each_entity(entity, subs->media_dev) {
+		switch (entity->type) {
+		case MEDIA_ENT_T_V4L2_SUBDEV_TUNER:
+			ret = media_entity_create_link(entity, 0,
+						 &subs->media_entity, 0,
+						 MEDIA_LNK_FL_ENABLED);
+			if (ret == 0)
+				subs->tuner_linked = 1;
+		break;
+		}
+	}
+	pr_info("media_stream_init(): tuner_linked = %d\n",
+		subs->tuner_linked);
+#endif
+}
+
 /*
  * initialize the substream instance.
  */
@@ -104,6 +143,7 @@  static void snd_usb_init_substream(struct snd_usb_stream *as,
 	subs->ep_num = fp->endpoint;
 	if (fp->channels > subs->channels_max)
 		subs->channels_max = fp->channels;
+	media_stream_init(subs);
 }
 
 /* kctl callbacks for usb-audio channel maps */
diff --git a/sound/usb/usbaudio.h b/sound/usb/usbaudio.h
index 91d0380..c2dbf1d 100644
--- a/sound/usb/usbaudio.h
+++ b/sound/usb/usbaudio.h
@@ -108,6 +108,7 @@  struct snd_usb_audio_quirk {
 	const char *product_name;
 	int16_t ifnum;
 	uint16_t type;
+	bool media_device;
 	const void *data;
 };