[alsa-devel] [PATCH MC Next Gen 1/2] sound/usb: Create media mixer function and control interface entities

[Shuah Khan]

Add support for creating MEDIA_ENT_F_AUDIO_MIXER entity for
each mixer and a MEDIA_INTF_T_ALSA_CONTROL control interface
entity that links to mixer entities. MEDIA_INTF_T_ALSA_CONTROL
entity corresponds to the control device for the card.

Signed-off-by: Shuah Khan <shuahkh at osg.samsung.com>
---
 sound/usb/card.c     |  5 ++++
 sound/usb/media.c    | 85 ++++++++++++++++++++++++++++++++++++++++++++++++++++
 sound/usb/media.h    |  4 +++
 sound/usb/mixer.h    |  1 +
 sound/usb/usbaudio.h |  1 +
 5 files changed, 96 insertions(+)

diff --git a/sound/usb/card.c b/sound/usb/card.c
index 469d2bf..d004cb4 100644
--- a/sound/usb/card.c
+++ b/sound/usb/card.c
@@ -560,6 +560,9 @@ static int usb_audio_probe(struct usb_interface *intf,
 	if (err < 0)
 		goto __error;
 
+	/* Create media entities for mixer and control dev */
+	media_mixer_init(chip);
+
 	usb_chip[chip->index] = chip;
 	chip->num_interfaces++;
 	chip->probing = 0;
@@ -616,6 +619,8 @@ static void usb_audio_disconnect(struct usb_interface *intf)
 		list_for_each(p, &chip->midi_list) {
 			snd_usbmidi_disconnect(p);
 		}
+		/* delete mixer media resources */
+		media_mixer_delete(chip);
 		/* release mixer resources */
 		list_for_each_entry(mixer, &chip->mixer_list, list) {
 			snd_usb_mixer_disconnect(mixer);
diff --git a/sound/usb/media.c b/sound/usb/media.c
index 0cbfee6..54b4052 100644
--- a/sound/usb/media.c
+++ b/sound/usb/media.c
@@ -199,4 +199,89 @@ void media_stop_pipeline(struct snd_usb_substream *subs)
 	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;
+	struct media_ctl *mctl;
+	u32 intf_type = MEDIA_INTF_T_ALSA_CONTROL;
+	int ret;
+
+	mdev = media_device_find_devres(&chip->dev->dev);
+	if (!mdev)
+		return -ENODEV;
+
+	ctl_intf = (struct media_intf_devnode *) 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;
+	}
+
+	list_for_each_entry(mixer, &chip->mixer_list, list) {
+
+		if (mixer->media_ctl)
+			continue;
+
+		/* allocate media_ctl */
+		mctl = kzalloc(sizeof(struct media_ctl), GFP_KERNEL);
+		if (!mctl)
+			return -ENOMEM;
+
+		mixer->media_ctl = (void *) mctl;
+		mctl->media_dev = mdev;
+
+		mctl->media_entity.function = MEDIA_ENT_F_AUDIO_MIXER;
+		mctl->media_entity.name = chip->card->mixername;
+		mctl->media_pad.flags = MEDIA_PAD_FL_SINK;
+		media_entity_init(&mctl->media_entity, 1, &mctl->media_pad);
+		ret =  media_device_register_entity(mctl->media_dev,
+						    &mctl->media_entity);
+		if (ret)
+			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);
+			return -ENOMEM;
+		}
+		mctl->intf_devnode = ctl_intf;
+	}
+	return 0;
+}
+
+void media_mixer_delete(struct snd_usb_audio *chip)
+{
+	struct usb_mixer_interface *mixer;
+	struct media_device *mdev;
+
+	mdev = media_device_find_devres(&chip->dev->dev);
+	if (!mdev)
+		return;
+
+	list_for_each_entry(mixer, &chip->mixer_list, list) {
+		struct media_ctl *mctl = mixer->media_ctl;
+
+		if (!mixer->media_ctl)
+			continue;
+
+		media_entity_remove_links(&mctl->media_entity);
+		media_device_unregister_entity(&mctl->media_entity);
+		media_entity_cleanup(&mctl->media_entity);
+		mctl->media_dev = NULL;
+		mctl->intf_devnode = NULL;
+		kfree(mctl);
+		mixer->media_ctl = NULL;
+	}
+	media_devnode_remove(chip->ctl_intf_media_devnode);
+}
+
 #endif
diff --git a/sound/usb/media.h b/sound/usb/media.h
index cdcfb80..fec46413 100644
--- a/sound/usb/media.h
+++ b/sound/usb/media.h
@@ -37,6 +37,8 @@ int media_stream_init(struct snd_usb_substream *subs, struct snd_pcm *pcm,
 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);
+int media_mixer_init(struct snd_usb_audio *chip);
+void media_mixer_delete(struct snd_usb_audio *chip);
 #else
 static inline int media_device_init(struct snd_usb_audio *chip,
 					struct usb_interface *iface)
@@ -49,5 +51,7 @@ 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) { }
+static int media_mixer_init(struct snd_usb_audio *chip) { return 0; }
+static void media_mixer_delete(struct snd_usb_audio *chip) { }
 #endif
 #endif /* __MEDIA_H */
diff --git a/sound/usb/mixer.h b/sound/usb/mixer.h
index d3268f0..1f9eed3 100644
--- a/sound/usb/mixer.h
+++ b/sound/usb/mixer.h
@@ -22,6 +22,7 @@ struct usb_mixer_interface {
 	struct urb *rc_urb;
 	struct usb_ctrlrequest *rc_setup_packet;
 	u8 rc_buffer[6];
+	void *media_ctl;
 };
 
 #define MAX_CHANNELS	16	/* max logical channels */
diff --git a/sound/usb/usbaudio.h b/sound/usb/usbaudio.h
index c2dbf1d..b2be7c3 100644
--- a/sound/usb/usbaudio.h
+++ b/sound/usb/usbaudio.h
@@ -59,6 +59,7 @@ struct snd_usb_audio {
 	bool autoclock;			/* from the 'autoclock' module param */
 
 	struct usb_host_interface *ctrl_intf;	/* the audio control interface */
+	void *ctl_intf_media_devnode;
 };
 
 #define usb_audio_err(chip, fmt, args...) \
-- 
2.1.4