ALSA: hda: Virtualize SPDIF out controls

The SPDIF output controls apply to converter widgets. A future change
will create a PCM device per pin widget, and hence a set of SPDIF output
controls per pin widget, for certain HDMI codecs. To support this, we
need the ability to virtualize the SPDIF output controls. Specifically:

* Controls can be "unassigned" from real hardware when a converter is
  not used for the PCM the control was created for.
* Control puts only write to hardware when they are assigned.
* Controls can be "assigned" to real hardware when a converter is picked
  to support output for a particular PCM.
* When a converter is assigned, the hardware is updated to the cached
  configuration.

Signed-off-by: Stephen Warren <swarren@nvidia.com>
Signed-off-by: Takashi Iwai <tiwai@suse.de>

1 files changed, 2 insertions, 0 deletions

diff --git a/sound/pci/hda/hda_codec.h b/sound/pci/hda/hda_codec.h
index 1d21c0624e03..96c35cab57bf 100644
--- a/sound/pci/hda/hda_codec.h
+++ b/sound/pci/hda/hda_codec.h
@@ -954,6 +954,8 @@ struct hda_spdif_out {
 };
 struct hda_spdif_out *snd_hda_spdif_out_of_nid(struct hda_codec *codec,
                                                hda_nid_t nid);
+void snd_hda_spdif_ctls_unassign(struct hda_codec *codec, int idx);
+void snd_hda_spdif_ctls_assign(struct hda_codec *codec, int idx, hda_nid_t nid);
 
 /*
  * Mixer