[PATCH v2 00/22] Sharing media resources across ALSA and au0828 drivers

@@ -65,6 +65,22 @@ static inline const char *intf_type(struct media_interface *intf)
 		return "v4l2-subdev";
 	case MEDIA_INTF_T_V4L_SWRADIO:
 		return "swradio";
+	case MEDIA_INTF_T_ALSA_PCM_CAPTURE:
+		return "pcm-capture";
+	case MEDIA_INTF_T_ALSA_PCM_PLAYBACK:
+		return "pcm-playback";
+	case MEDIA_INTF_T_ALSA_CONTROL:
+		return "alsa-control";
+	case MEDIA_INTF_T_ALSA_COMPRESS:
+		return "compress";
+	case MEDIA_INTF_T_ALSA_RAWMIDI:
+		return "rawmidi";
+	case MEDIA_INTF_T_ALSA_HWDEP:
+		return "hwdep";
+	case MEDIA_INTF_T_ALSA_SEQUENCER:
+		return "sequencer";
+	case MEDIA_INTF_T_ALSA_TIMER:
+		return "timer";
 	default:
 		return "unknown-intf";
 	}

@@ -265,6 +265,7 @@ struct media_links_enum {
 
 #define MEDIA_INTF_T_DVB_BASE	0x00000100
 #define MEDIA_INTF_T_V4L_BASE	0x00000200
+#define MEDIA_INTF_T_ALSA_BASE	0x00000300
 
 /* Interface types */
 

@@ -280,6 +281,27 @@ struct media_links_enum {
 #define MEDIA_INTF_T_V4L_SUBDEV (MEDIA_INTF_T_V4L_BASE + 3)
 #define MEDIA_INTF_T_V4L_SWRADIO (MEDIA_INTF_T_V4L_BASE + 4)
 
+/**
+ * DOC: Media Controller Next Generation ALSA Interface Types
+ *
+ * MEDIA_INTF_T_ALSA_PCM_CAPTURE - PCM Capture Interface (pcm-capture)
+ * MEDIA_INTF_T_ALSA_PCM_PLAYBACK -  PCM Playback Interface (pcm-playback)
+ * MEDIA_INTF_T_ALSA_CONTROL -  ALSA Control Interface (alsa-control)
+ * MEDIA_INTF_T_ALSA_COMPRESS - ALSA Compression Interface (compress)
+ * MEDIA_INTF_T_ALSA_RAWMIDI - ALSA Raw MIDI Interface (rawmidi)
+ * MEDIA_INTF_T_ALSA_HWDEP - ALSA Hardware Dependent Interface (hwdep)
+ * MEDIA_INTF_T_ALSA_SEQUENCER - ALSA Sequencer (sequencer)
+ * MEDIA_INTF_T_ALSA_TIMER - ALSA Timer (timer)
+ */
+#define MEDIA_INTF_T_ALSA_PCM_CAPTURE   (MEDIA_INTF_T_ALSA_BASE)
+#define MEDIA_INTF_T_ALSA_PCM_PLAYBACK  (MEDIA_INTF_T_ALSA_BASE + 1)
+#define MEDIA_INTF_T_ALSA_CONTROL       (MEDIA_INTF_T_ALSA_BASE + 2)
+#define MEDIA_INTF_T_ALSA_COMPRESS      (MEDIA_INTF_T_ALSA_BASE + 3)
+#define MEDIA_INTF_T_ALSA_RAWMIDI       (MEDIA_INTF_T_ALSA_BASE + 4)
+#define MEDIA_INTF_T_ALSA_HWDEP         (MEDIA_INTF_T_ALSA_BASE + 5)
+#define MEDIA_INTF_T_ALSA_SEQUENCER     (MEDIA_INTF_T_ALSA_BASE + 6)
+#define MEDIA_INTF_T_ALSA_TIMER         (MEDIA_INTF_T_ALSA_BASE + 7)
+
 /*
  * MC next gen API definitions
  *

@@ -98,6 +98,17 @@ struct media_device_info {
 #define MEDIA_ENT_F_IF_AUD_DECODER	(MEDIA_ENT_F_BASE + 42)
 
 /*
+ * DOC: Media Controller Next Generation ALSA Function Entities
+ *
+ * MEDIA_ENT_F_AUDIO_CAPTURE - Audio Capture Function
+ * MEDIA_ENT_F_AUDIO_PLAYBACK - Audio Play Back Function
+ * MEDIA_ENT_F_AUDIO_MIXER - Audio Mixer Function
+*/
+#define MEDIA_ENT_F_AUDIO_CAPTURE	(MEDIA_ENT_F_BASE + 200)
+#define MEDIA_ENT_F_AUDIO_PLAYBACK	(MEDIA_ENT_F_BASE + 201)
+#define MEDIA_ENT_F_AUDIO_MIXER		(MEDIA_ENT_F_BASE + 202)
+
+/*
  * Don't touch on those. The ranges MEDIA_ENT_F_OLD_BASE and
  * MEDIA_ENT_F_OLD_SUBDEV_BASE are kept to keep backward compatibility
  * with the legacy v1 API.The number range is out of range by purpose:

@@ -6,7 +6,7 @@ tuner-objs	:=	tuner-core.o
 
 videodev-objs	:=	v4l2-dev.o v4l2-ioctl.o v4l2-device.o v4l2-fh.o \
 			v4l2-event.o v4l2-ctrls.o v4l2-subdev.o v4l2-clk.o \
-			v4l2-async.o
+			v4l2-async.o v4l2-mc.o
 ifeq ($(CONFIG_COMPAT),y)
   videodev-objs += v4l2-compat-ioctl32.o
 endif

@@ -0,0 +1,60 @@
+/*
+ * v4l2-mc.c - Media Controller V4L2 Common Interfaces
+ *
+ * Copyright (C) 2016 Shuah Khan <shuahkh@osg.samsung.com>
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation; either version 2 of the License, or
+ * (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ */
+
+#include <media/v4l2-mc.h>
+#include <media/media-device.h>
+#include <media/videobuf2-core.h>
+#include <media/v4l2-fh.h>
+
+int v4l_enable_media_source(struct video_device *vdev)
+{
+#ifdef CONFIG_MEDIA_CONTROLLER
+	struct media_device *mdev = vdev->entity.graph_obj.mdev;
+	int ret;
+
+	if (!mdev || !mdev->enable_source)
+		return 0;
+	ret = mdev->enable_source(&vdev->entity, &vdev->pipe);
+	if (ret)
+		return -EBUSY;
+	return 0;
+#endif /* CONFIG_MEDIA_CONTROLLER */
+	return 0;
+}
+EXPORT_SYMBOL_GPL(v4l_enable_media_source);
+
+void v4l_disable_media_source(struct video_device *vdev)
+{
+#ifdef CONFIG_MEDIA_CONTROLLER
+	struct media_device *mdev = vdev->entity.graph_obj.mdev;
+
+	if (mdev && mdev->disable_source)
+		mdev->disable_source(&vdev->entity);
+#endif /* CONFIG_MEDIA_CONTROLLER */
+}
+EXPORT_SYMBOL_GPL(v4l_disable_media_source);
+
+int v4l_vb2q_enable_media_source(struct vb2_queue *q)
+{
+#ifdef CONFIG_MEDIA_CONTROLLER
+	struct v4l2_fh *fh = q->owner;
+
+	return v4l_enable_media_source(fh->vdev);
+#endif /* CONFIG_MEDIA_CONTROLLER */
+	return 0;
+}
+EXPORT_SYMBOL_GPL(v4l_vb2q_enable_media_source);
+

@@ -87,6 +87,7 @@ struct video_device
 #if defined(CONFIG_MEDIA_CONTROLLER)
 	struct media_entity entity;
 	struct media_intf_devnode *intf_devnode;
+	struct media_pipeline pipe;
 #endif
 	/* device ops */
 	const struct v4l2_file_operations *fops;

@@ -14,6 +14,11 @@
  * GNU General Public License for more details.
  */
 
+#ifndef _V4L2_MC_H
+#define _V4L2_MC_H
+
+#include <media/v4l2-dev.h>
+
 /**
  * enum tuner_pad_index - tuner pad index for MEDIA_ENT_F_TUNER
  *

@@ -89,3 +94,50 @@ enum demod_pad_index {
 	DEMOD_PAD_VBI_OUT,
 	DEMOD_NUM_PADS
 };
+
+/**
+ * v4l_enable_media_source() -	Hold media source for exclusive use
+ *				if free
+ *
+ * @vdev - poniter to struct video_device
+ *
+ * This interface calls enable_source handler to determine if
+ * media source is free for use. The enable_source handler is
+ * responsible for checking is the media source is free and
+ * start a pipeline between the media source and the media
+ * entity associated with the video device. This interface
+ * should be called from v4l2-core and dvb-core interfaces
+ * that change the source configuration.
+ *
+ * Return: returns zero on success or a negative error code.
+ */
+int v4l_enable_media_source(struct video_device *vdev);
+
+/**
+ * v4l_disable_media_source() -	Release media source
+ *
+ * @vdev - poniter to struct video_device
+ *
+ * This interface calls disable_source handler to release
+ * the media source. The disable_source handler stops the
+ * active media pipeline between the media source and the
+ * media entity associated with the video device.
+ *
+ * Return: returns zero on success or a negative error code.
+ */
+void v4l_disable_media_source(struct video_device *vdev);
+/*
+ * v4l_vb2q_enable_media_tuner -  Hold media source for exclusive use
+ *				  if free.
+ * @q - pointer to struct vb2_queue
+ *
+ * Wrapper for v4l_enable_media_source(). This function should
+ * be called from v4l2-core to enable the media source with
+ * pointer to struct vb2_queue as the input argument. Some
+ * v4l2-core interfaces don't have access to video device and
+ * this interface finds the struct video_device for the q and
+ * calls v4l_enable_media_source().
+ */
+int v4l_vb2q_enable_media_source(struct vb2_queue *q);
+
+#endif /* _V4L2_MC_H */

@@ -365,8 +365,8 @@ EXPORT_SYMBOL_GPL(media_entity_graph_walk_next);
  * Pipeline management
  */
 
-__must_check int media_entity_pipeline_start(struct media_entity *entity,
-					     struct media_pipeline *pipe)
+__must_check int __media_entity_pipeline_start(struct media_entity *entity,
+					       struct media_pipeline *pipe)
 {
 	struct media_device *mdev = entity->graph_obj.mdev;
 	struct media_entity_graph *graph = &pipe->graph;

@@ -374,8 +374,6 @@ __must_check int media_entity_pipeline_start(struct media_entity *entity,
 	struct media_link *link;
 	int ret;
 
-	mutex_lock(&mdev->graph_mutex);
-
 	if (!pipe->streaming_count++) {
 		ret = media_entity_graph_walk_init(&pipe->graph, mdev);
 		if (ret)

@@ -456,8 +454,6 @@ __must_check int media_entity_pipeline_start(struct media_entity *entity,
 		}
 	}
 
-	mutex_unlock(&mdev->graph_mutex);
-
 	return 0;
 
 error:

@@ -487,19 +483,28 @@ error_graph_walk_start:
 	if (!--pipe->streaming_count)
 		media_entity_graph_walk_cleanup(graph);
 
-	mutex_unlock(&mdev->graph_mutex);
+	return ret;
+}
+EXPORT_SYMBOL_GPL(__media_entity_pipeline_start);
 
+__must_check int media_entity_pipeline_start(struct media_entity *entity,
+					     struct media_pipeline *pipe)
+{
+	struct media_device *mdev = entity->graph_obj.mdev;
+	int ret;
+
+	mutex_lock(&mdev->graph_mutex);
+	ret = __media_entity_pipeline_start(entity, pipe);
+	mutex_unlock(&mdev->graph_mutex);
 	return ret;
 }
 EXPORT_SYMBOL_GPL(media_entity_pipeline_start);
 
-void media_entity_pipeline_stop(struct media_entity *entity)
+void __media_entity_pipeline_stop(struct media_entity *entity)
 {
-	struct media_device *mdev = entity->graph_obj.mdev;
 	struct media_entity_graph *graph = &entity->pipe->graph;
 	struct media_pipeline *pipe = entity->pipe;
 
-	mutex_lock(&mdev->graph_mutex);
 
 	WARN_ON(!pipe->streaming_count);
 	media_entity_graph_walk_start(graph, entity);

@@ -516,6 +521,15 @@ void media_entity_pipeline_stop(struct media_entity *entity)
 	if (!--pipe->streaming_count)
 		media_entity_graph_walk_cleanup(graph);
 
+}
+EXPORT_SYMBOL_GPL(__media_entity_pipeline_stop);
+
+void media_entity_pipeline_stop(struct media_entity *entity)
+{
+	struct media_device *mdev = entity->graph_obj.mdev;
+
+	mutex_lock(&mdev->graph_mutex);
+	__media_entity_pipeline_stop(entity);
 	mutex_unlock(&mdev->graph_mutex);
 }
 EXPORT_SYMBOL_GPL(media_entity_pipeline_stop);

@@ -832,6 +832,12 @@ media_entity_graph_walk_next(struct media_entity_graph *graph);
  */
 __must_check int media_entity_pipeline_start(struct media_entity *entity,
 					     struct media_pipeline *pipe);
+/**
+ * non-locking __media_entity_pipeline_start() can be called from
+ * code paths that hold the graph_mutex
+ */
+__must_check int __media_entity_pipeline_start(struct media_entity *entity,
+					       struct media_pipeline *pipe);
 
 /**
  * media_entity_pipeline_stop - Mark a pipeline as not streaming

@@ -848,6 +854,12 @@ __must_check int media_entity_pipeline_start(struct media_entity *entity,
 void media_entity_pipeline_stop(struct media_entity *entity);
 
 /**
+ * non-locking __media_entity_pipeline_stop() can be called from
+ * code paths that hold the graph_mutex
+ */
+void __media_entity_pipeline_stop(struct media_entity *entity);
+
+/**
  * media_devnode_create() - creates and initializes a device node interface
  *
  * @mdev:	pointer to struct &media_device

@@ -805,6 +805,7 @@ int __media_entity_setup_link(struct media_link *link, u32 flags)
 
 	return ret;
 }
+EXPORT_SYMBOL_GPL(__media_entity_setup_link);
 
 int media_entity_setup_link(struct media_link *link, u32 flags)
 {

@@ -134,10 +134,10 @@ static void au0828_unregister_media_device(struct au0828_dev *dev)
 {
 
 #ifdef CONFIG_MEDIA_CONTROLLER
-	if (dev->media_dev) {
+	if (dev->media_dev &&
+		media_devnode_is_registered(&dev->media_dev->devnode)) {
 		media_device_unregister(dev->media_dev);
 		media_device_cleanup(dev->media_dev);
-		kfree(dev->media_dev);
 		dev->media_dev = NULL;
 	}
 #endif

@@ -223,23 +223,24 @@ static int au0828_media_device_init(struct au0828_dev *dev,
 #ifdef CONFIG_MEDIA_CONTROLLER
 	struct media_device *mdev;
 
-	mdev = kzalloc(sizeof(*mdev), GFP_KERNEL);
+	mdev = media_device_get_devres(&udev->dev);
 	if (!mdev)
 		return -ENOMEM;
 
-	mdev->dev = &udev->dev;
+	if (!media_devnode_is_registered(&mdev->devnode)) {
+		mdev->dev = &udev->dev;
 
-	if (!dev->board.name)
-		strlcpy(mdev->model, "unknown au0828", sizeof(mdev->model));
-	else
-		strlcpy(mdev->model, dev->board.name, sizeof(mdev->model));
-	if (udev->serial)
-		strlcpy(mdev->serial, udev->serial, sizeof(mdev->serial));
-	strcpy(mdev->bus_info, udev->devpath);
-	mdev->hw_revision = le16_to_cpu(udev->descriptor.bcdDevice);
-	mdev->driver_version = LINUX_VERSION_CODE;
+		if (udev->product)
+			strlcpy(mdev->model, udev->product,
+				sizeof(mdev->model));
+		if (udev->serial)
+			strlcpy(mdev->serial, udev->serial,
+				sizeof(mdev->serial));
+		strcpy(mdev->bus_info, udev->devpath);
+		mdev->hw_revision = le16_to_cpu(udev->descriptor.bcdDevice);
 
-	media_device_init(mdev);
+		media_device_init(mdev);
+	}
 
 	dev->media_dev = mdev;
 #endif

@@ -227,7 +227,8 @@ static int au0828_media_device_init(struct au0828_dev *dev,
 	if (!mdev)
 		return -ENOMEM;
 
-	if (!media_devnode_is_registered(&mdev->devnode)) {
+	/* check if media device is already initialized */
+	if (!mdev->dev) {
 		mdev->dev = &udev->dev;
 
 		if (udev->product)

@@ -325,6 +326,27 @@ static int au0828_create_media_graph(struct au0828_dev *dev)
 	return 0;
 }
 
+static int au0828_media_device_register(struct au0828_dev *dev,
+					struct usb_device *udev)
+{
+#ifdef CONFIG_MEDIA_CONTROLLER
+	int ret;
+
+	if (dev->media_dev &&
+		!media_devnode_is_registered(&dev->media_dev->devnode)) {
+
+		/* register media device */
+		ret = media_device_register(dev->media_dev);
+		if (ret) {
+			dev_err(&udev->dev,
+				"Media Device Register Error: %d\n", ret);
+			return ret;
+		}
+	}
+#endif
+	return 0;
+}
+
 static int au0828_usb_probe(struct usb_interface *interface,
 	const struct usb_device_id *id)
 {

@@ -452,7 +474,7 @@ static int au0828_usb_probe(struct usb_interface *interface,
 	}
 
 #ifdef CONFIG_MEDIA_CONTROLLER
-	retval = media_device_register(dev->media_dev);
+	retval = au0828_media_device_register(dev, usbdev);
 #endif
 
 done:

@@ -278,9 +278,9 @@ static int au0828_create_media_graph(struct au0828_dev *dev)
 		return -EINVAL;
 
 	if (tuner) {
+		/* create tuner to decoder link in deactivated state */
 		ret = media_create_pad_link(tuner, TUNER_PAD_OUTPUT,
-					    decoder, 0,
-					    MEDIA_LNK_FL_ENABLED);
+					    decoder, 0, 0);
 		if (ret)
 			return ret;
 	}

@@ -747,17 +747,17 @@ void media_device_unregister(struct media_device *mdev)
 	struct media_entity *next;
 	struct media_interface *intf, *tmp_intf;
 	struct media_entity_notify *notify, *nextp;
+	int ret;
 
 	if (mdev == NULL)
 		return;
 
-	spin_lock(&mdev->lock);
-
-	/* Check if mdev was ever registered at all */
-	if (!media_devnode_is_registered(&mdev->devnode)) {
-		spin_unlock(&mdev->lock);
+	/* Start unregister - continue if necessary */
+	ret = media_devnode_start_unregister(&mdev->devnode);
+	if (ret)
 		return;
-	}
+
+	spin_lock(&mdev->lock);
 
 	/* Remove all entities from the media device */
 	list_for_each_entry_safe(entity, next, &mdev->entities, graph_obj.list)

@@ -272,15 +272,20 @@ error:
 	return ret;
 }
 
-void media_devnode_unregister(struct media_devnode *mdev)
+int __must_check media_devnode_start_unregister(struct media_devnode *mdev)
 {
-	/* Check if mdev was ever registered at all */
-	if (!media_devnode_is_registered(mdev))
-		return;
-
 	mutex_lock(&media_devnode_lock);
+	if (!media_devnode_is_registered(mdev)) {
+		mutex_unlock(&media_devnode_lock);
+		return -EINVAL;
+	}
 	clear_bit(MEDIA_FLAG_REGISTERED, &mdev->flags);
 	mutex_unlock(&media_devnode_lock);
+	return 0;
+}
+
+void media_devnode_unregister(struct media_devnode *mdev)
+{
 	device_unregister(&mdev->dev);
 }
 

@@ -120,6 +120,23 @@ int __must_check media_devnode_register(struct media_devnode *mdev,
 					struct module *owner);
 
 /**
+ * media_devnode_start_unregister - start unregister on a media device node
+ * @mdev: the device node to start unregister
+ *
+ * This clears the MEDIA_FLAG_REGISTERED bit to indicate that unregister
+ * is in progress.
+ *
+ * This function can safely be called if the device node has never been
+ * registered or has already been unregistered.
+ *
+ * Zero is returned on success.
+ *
+ * -EINVAL is returned if the device node has never been
+ * registered or has already been unregistered.
+ */
+int __must_check media_devnode_start_unregister(struct media_devnode *mdev);
+
+/**
  * media_devnode_unregister - unregister a media device node
  * @mdev: the device node to unregister
  *

@@ -15,6 +15,7 @@ config SND_USB_AUDIO
 	select SND_RAWMIDI
 	select SND_PCM
 	select BITREVERSE
+	select SND_USB_AUDIO_USE_MEDIA_CONTROLLER	if MEDIA_CONTROLLER
 	help
 	  Say Y here to include support for USB audio and USB MIDI
 	  devices.

@@ -22,6 +23,9 @@ config SND_USB_AUDIO
 	  To compile this driver as a module, choose M here: the module
 	  will be called snd-usb-audio.
 
+config SND_USB_AUDIO_USE_MEDIA_CONTROLLER
+	bool
+
 config SND_USB_UA101
 	tristate "Edirol UA-101/UA-1000 driver"
 	select SND_PCM

@@ -15,6 +15,8 @@ snd-usb-audio-objs := 	card.o \
 			quirks.o \
 			stream.o
 
+snd-usb-audio-$(CONFIG_SND_USB_AUDIO_USE_MEDIA_CONTROLLER) += media.o
+
 snd-usbmidi-lib-objs := midi.o
 
 # Toplevel Module Dependency

@@ -66,6 +66,7 @@
 #include "format.h"
 #include "power.h"
 #include "stream.h"
+#include "media.h"
 
 MODULE_AUTHOR("Takashi Iwai <tiwai@suse.de>");
 MODULE_DESCRIPTION("USB Audio");

@@ -561,6 +562,11 @@ static int usb_audio_probe(struct usb_interface *intf,
 	if (err < 0)
 		goto __error;
 
+	if (quirk->media_device) {
+		/* don't want to fail when media_device_create() fails */
+		media_device_create(chip, intf);
+	}
+
 	usb_chip[chip->index] = chip;
 	chip->num_interfaces++;
 	usb_set_intfdata(intf, chip);

@@ -617,6 +623,14 @@ static void usb_audio_disconnect(struct usb_interface *intf)
 		list_for_each(p, &chip->midi_list) {
 			snd_usbmidi_disconnect(p);
 		}
+		/*
+		 * Nice to check quirk && quirk->media_device
+		 * need some special handlings. Doesn't look like
+		 * we have access to quirk here
+		 * Acceses mixer_list
+		*/
+		media_device_delete(chip);
+
 		/* release mixer resources */
 		list_for_each_entry(mixer, &chip->mixer_list, list) {
 			snd_usb_mixer_disconnect(mixer);

@@ -156,6 +156,7 @@ struct snd_usb_substream {
 	} dsd_dop;
 
 	bool trigger_tstamp_pending_update; /* trigger timestamp being updated from initial estimate */
+	void *media_ctl;
 };
 
 struct snd_usb_stream {

@@ -0,0 +1,319 @@
+/*
+ * media.c - Media Controller specific ALSA driver code
+ *
+ * Copyright (c) 2015 Shuah Khan <shuahkh@osg.samsung.com>
+ * Copyright (c) 2015 Samsung Electronics Co., Ltd.
+ *
+ * This file is released under the GPLv2.
+ */
+
+/*
+ * This file adds Media Controller support to ALSA driver
+ * to use the Media Controller API to share tuner with DVB
+ * and V4L2 drivers that control media device. Media device
+ * is created based on existing quirks framework. Using this
+ * approach, the media controller API usage can be added for
+ * a specific device.
+*/
+
+#include <linux/init.h>
+#include <linux/list.h>
+#include <linux/mutex.h>
+#include <linux/slab.h>
+#include <linux/usb.h>
+
+#include <sound/pcm.h>
+#include <sound/core.h>
+
+#include "usbaudio.h"
+#include "card.h"
+#include "mixer.h"
+#include "media.h"
+
+static int media_enable_source(struct media_ctl *mctl)
+{
+	if (mctl && mctl->media_dev->enable_source)
+		return mctl->media_dev->enable_source(&mctl->media_entity,
+						      &mctl->media_pipe);
+	return 0;
+}
+
+static void media_disable_source(struct media_ctl *mctl)
+{
+	if (mctl && mctl->media_dev->disable_source)
+		mctl->media_dev->disable_source(&mctl->media_entity);
+}
+
+int media_stream_init(struct snd_usb_substream *subs, struct snd_pcm *pcm,
+			int stream)
+{
+	struct media_device *mdev;
+	struct media_ctl *mctl;
+	struct device *pcm_dev = &pcm->streams[stream].dev;
+	u32 intf_type;
+	int ret = 0;
+	u16 mixer_pad;
+	struct media_entity *entity;
+
+	mdev = subs->stream->chip->media_dev;
+	if (!mdev)
+		return -ENODEV;
+
+	if (subs->media_ctl)
+		return 0;
+
+	/* allocate media_ctl */
+	mctl = kzalloc(sizeof(*mctl), GFP_KERNEL);
+	if (!mctl)
+		return -ENOMEM;
+
+	mctl->media_dev = mdev;
+	if (stream == SNDRV_PCM_STREAM_PLAYBACK) {
+		intf_type = MEDIA_INTF_T_ALSA_PCM_PLAYBACK;
+		mctl->media_entity.function = MEDIA_ENT_F_AUDIO_PLAYBACK;
+		mctl->media_pad.flags = MEDIA_PAD_FL_SOURCE;
+		mixer_pad = 1;
+	} else {
+		intf_type = MEDIA_INTF_T_ALSA_PCM_CAPTURE;
+		mctl->media_entity.function = MEDIA_ENT_F_AUDIO_CAPTURE;
+		mctl->media_pad.flags = MEDIA_PAD_FL_SINK;
+		mixer_pad = 2;
+	}
+	mctl->media_entity.name = pcm->name;
+	media_entity_pads_init(&mctl->media_entity, 1, &mctl->media_pad);
+	ret =  media_device_register_entity(mctl->media_dev,
+					    &mctl->media_entity);
+	if (ret)
+		goto err1;
+
+	mctl->intf_devnode = media_devnode_create(mdev, intf_type, 0,
+						  MAJOR(pcm_dev->devt),
+						  MINOR(pcm_dev->devt));
+	if (!mctl->intf_devnode) {
+		ret = -ENOMEM;
+		goto err2;
+	}
+	mctl->intf_link = media_create_intf_link(&mctl->media_entity,
+						 &mctl->intf_devnode->intf,
+						 MEDIA_LNK_FL_ENABLED);
+	if (!mctl->intf_link) {
+		ret = -ENOMEM;
+		goto err3;
+	}
+
+	/* create link between mixer and audio */
+	media_device_for_each_entity(entity, mdev) {
+		switch (entity->function) {
+		case MEDIA_ENT_F_AUDIO_MIXER:
+			ret = media_create_pad_link(entity, mixer_pad,
+						    &mctl->media_entity, 0,
+						    MEDIA_LNK_FL_ENABLED);
+			if (ret)
+				goto err4;
+			break;
+		}
+	}
+
+	subs->media_ctl = mctl;
+	return 0;
+
+err4:
+	media_remove_intf_link(mctl->intf_link);
+err3:
+	media_devnode_remove(mctl->intf_devnode);
+err2:
+	media_device_unregister_entity(&mctl->media_entity);
+err1:
+	kfree(mctl);
+	return ret;
+}
+
+void media_stream_delete(struct snd_usb_substream *subs)
+{
+	struct media_ctl *mctl = subs->media_ctl;
+
+	if (mctl && mctl->media_dev) {
+		struct media_device *mdev;
+
+		mdev = subs->stream->chip->media_dev;
+		if (mdev && media_devnode_is_registered(&mdev->devnode)) {
+			media_devnode_remove(mctl->intf_devnode);
+			media_device_unregister_entity(&mctl->media_entity);
+			media_entity_cleanup(&mctl->media_entity);
+		}
+		kfree(mctl);
+		subs->media_ctl = NULL;
+	}
+}
+
+int media_start_pipeline(struct snd_usb_substream *subs)
+{
+	struct media_ctl *mctl = subs->media_ctl;
+
+	if (mctl)
+		return media_enable_source(mctl);
+	return 0;
+}
+
+void media_stop_pipeline(struct snd_usb_substream *subs)
+{
+	struct media_ctl *mctl = subs->media_ctl;
+
+	if (mctl)
+		media_disable_source(mctl);
+}
+
+int media_mixer_init(struct snd_usb_audio *chip)
+{
+	struct device *ctl_dev = &chip->card->ctl_dev;
+	struct media_intf_devnode *ctl_intf;
+	struct usb_mixer_interface *mixer;
+	struct media_device *mdev = chip->media_dev;
+	struct media_mixer_ctl *mctl;
+	u32 intf_type = MEDIA_INTF_T_ALSA_CONTROL;
+	int ret;
+
+	if (!mdev)
+		return -ENODEV;
+
+	ctl_intf = chip->ctl_intf_media_devnode;
+	if (!ctl_intf) {
+		ctl_intf = (void *) media_devnode_create(mdev,
+							 intf_type, 0,
+							 MAJOR(ctl_dev->devt),
+							 MINOR(ctl_dev->devt));
+		if (!ctl_intf)
+			return -ENOMEM;
+		chip->ctl_intf_media_devnode = ctl_intf;
+	}
+
+	list_for_each_entry(mixer, &chip->mixer_list, list) {
+
+		if (mixer->media_mixer_ctl)
+			continue;
+
+		/* allocate media_mixer_ctl */
+		mctl = kzalloc(sizeof(*mctl), GFP_KERNEL);
+		if (!mctl)
+			return -ENOMEM;
+
+		mctl->media_dev = mdev;
+		mctl->media_entity.function = MEDIA_ENT_F_AUDIO_MIXER;
+		mctl->media_entity.name = chip->card->mixername;
+		mctl->media_pad[0].flags = MEDIA_PAD_FL_SINK;
+		mctl->media_pad[1].flags = MEDIA_PAD_FL_SOURCE;
+		mctl->media_pad[2].flags = MEDIA_PAD_FL_SOURCE;
+		media_entity_pads_init(&mctl->media_entity, MEDIA_MIXER_PAD_MAX,
+				  mctl->media_pad);
+		ret =  media_device_register_entity(mctl->media_dev,
+						    &mctl->media_entity);
+		if (ret) {
+			kfree(mctl);
+			return ret;
+		}
+
+		mctl->intf_link = media_create_intf_link(&mctl->media_entity,
+							 &ctl_intf->intf,
+							 MEDIA_LNK_FL_ENABLED);
+		if (!mctl->intf_link) {
+			media_device_unregister_entity(&mctl->media_entity);
+			media_entity_cleanup(&mctl->media_entity);
+			kfree(mctl);
+			return -ENOMEM;
+		}
+		mctl->intf_devnode = ctl_intf;
+		mixer->media_mixer_ctl = mctl;
+	}
+	return 0;
+}
+
+static void media_mixer_delete(struct snd_usb_audio *chip)
+{
+	struct usb_mixer_interface *mixer;
+	struct media_device *mdev = chip->media_dev;
+
+	if (!mdev)
+		return;
+
+	list_for_each_entry(mixer, &chip->mixer_list, list) {
+		struct media_mixer_ctl *mctl;
+
+		mctl = mixer->media_mixer_ctl;
+		if (!mixer->media_mixer_ctl)
+			continue;
+
+		if (media_devnode_is_registered(&mdev->devnode)) {
+			media_device_unregister_entity(&mctl->media_entity);
+			media_entity_cleanup(&mctl->media_entity);
+		}
+		kfree(mctl);
+		mixer->media_mixer_ctl = NULL;
+	}
+	if (media_devnode_is_registered(&mdev->devnode))
+		media_devnode_remove(chip->ctl_intf_media_devnode);
+	chip->ctl_intf_media_devnode = NULL;
+}
+
+int media_device_create(struct snd_usb_audio *chip,
+			struct usb_interface *iface)
+{
+	struct media_device *mdev;
+	struct usb_device *usbdev = interface_to_usbdev(iface);
+	int ret;
+
+	mdev = media_device_get_devres(&usbdev->dev);
+	if (!mdev)
+		return -ENOMEM;
+	if (!mdev->dev) {
+		/* 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);
+		media_device_init(mdev);
+	}
+	if (!media_devnode_is_registered(&mdev->devnode)) {
+		ret = media_device_register(mdev);
+		if (ret) {
+			dev_err(&usbdev->dev,
+				"Couldn't register media device. Error: %d\n",
+				ret);
+			return ret;
+		}
+	}
+
+	/* save media device - avoid lookups */
+	chip->media_dev = mdev;
+
+	/* Create media entities for mixer and control dev */
+	ret = media_mixer_init(chip);
+	if (ret) {
+		dev_err(&usbdev->dev,
+			"Couldn't create media mixer entities. Error: %d\n",
+			ret);
+
+		/* clear saved media_dev */
+		chip->media_dev = NULL;
+
+		return ret;
+	}
+	return 0;
+}
+
+void media_device_delete(struct snd_usb_audio *chip)
+{
+	struct media_device *mdev = chip->media_dev;
+
+	media_mixer_delete(chip);
+
+	if (mdev) {
+		if (media_devnode_is_registered(&mdev->devnode))
+			media_device_unregister(mdev);
+		chip->media_dev = NULL;
+	}
+}

@@ -0,0 +1,72 @@
+/*
+ * media.h - Media Controller specific ALSA driver code
+ *
+ * Copyright (c) 2015 Shuah Khan <shuahkh@osg.samsung.com>
+ * Copyright (c) 2015 Samsung Electronics Co., Ltd.
+ *
+ * This file is released under the GPLv2.
+ */
+
+/*
+ * This file adds Media Controller support to ALSA driver
+ * to use the Media Controller API to share tuner with DVB
+ * and V4L2 drivers that control media device. Media device
+ * is created based on existing quirks framework. Using this
+ * approach, the media controller API usage can be added for
+ * a specific device.
+*/
+#ifndef __MEDIA_H
+
+#ifdef CONFIG_SND_USB_AUDIO_USE_MEDIA_CONTROLLER
+
+#include <media/media-device.h>
+#include <media/media-entity.h>
+#include <sound/asound.h>
+
+struct media_ctl {
+	struct media_device *media_dev;
+	struct media_entity media_entity;
+	struct media_intf_devnode *intf_devnode;
+	struct media_link *intf_link;
+	struct media_pad media_pad;
+	struct media_pipeline media_pipe;
+};
+
+/*
+ * One source pad each for SNDRV_PCM_STREAM_CAPTURE and
+ * SNDRV_PCM_STREAM_PLAYBACK. One for sink pad to link
+ * to AUDIO Source
+*/
+#define MEDIA_MIXER_PAD_MAX    (SNDRV_PCM_STREAM_LAST + 2)
+
+struct media_mixer_ctl {
+	struct media_device *media_dev;
+	struct media_entity media_entity;
+	struct media_intf_devnode *intf_devnode;
+	struct media_link *intf_link;
+	struct media_pad media_pad[MEDIA_MIXER_PAD_MAX];
+	struct media_pipeline media_pipe;
+};
+
+int media_device_create(struct snd_usb_audio *chip,
+			struct usb_interface *iface);
+void media_device_delete(struct snd_usb_audio *chip);
+int media_stream_init(struct snd_usb_substream *subs, struct snd_pcm *pcm,
+			int stream);
+void media_stream_delete(struct snd_usb_substream *subs);
+int media_start_pipeline(struct snd_usb_substream *subs);
+void media_stop_pipeline(struct snd_usb_substream *subs);
+#else
+static inline int media_device_create(struct snd_usb_audio *chip,
+				      struct usb_interface *iface)
+						{ return 0; }
+static inline void media_device_delete(struct snd_usb_audio *chip) { }
+static inline int media_stream_init(struct snd_usb_substream *subs,
+					struct snd_pcm *pcm, int stream)
+						{ return 0; }
+static inline void media_stream_delete(struct snd_usb_substream *subs) { }
+static inline int media_start_pipeline(struct snd_usb_substream *subs)
+					{ return 0; }
+static inline void media_stop_pipeline(struct snd_usb_substream *subs) { }
+#endif
+#endif /* __MEDIA_H */