ALSA: PCM: channel mapping API implementation
This patch implements the basic data types for the standard channel
mapping API handling.
- The definitions of the channel positions and the new TLV types are
added in sound/asound.h and sound/tlv.h, so that they can be
referred from user-space.
- Introduced a new helper function snd_pcm_add_chmap_ctls() to create
control elements representing the channel maps for each PCM
(sub)stream.
- Some standard pre-defined channel maps are provided for
convenience.
Signed-off-by: Takashi Iwai <tiwai@suse.de>
diff --git a/include/sound/tlv.h b/include/sound/tlv.h
index a64d8fe..28c65e1 100644
--- a/include/sound/tlv.h
+++ b/include/sound/tlv.h
@@ -86,4 +86,12 @@
#define TLV_DB_GAIN_MUTE -9999999
+/*
+ * channel-mapping TLV items
+ * TLV length must match with num_channels
+ */
+#define SNDRV_CTL_TLVT_CHMAP_FIXED 0x101 /* fixed channel position */
+#define SNDRV_CTL_TLVT_CHMAP_VAR 0x102 /* channels freely swappable */
+#define SNDRV_CTL_TLVT_CHMAP_PAIRED 0x103 /* pair-wise swappable */
+
#endif /* __SOUND_TLV_H */