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>

1 files changed, 30 insertions, 0 deletions

diff --git a/include/sound/asound.h b/include/sound/asound.h
index 0876a1e76aef..376e75632e07 100644
--- a/include/sound/asound.h
+++ b/include/sound/asound.h
@@ -472,6 +472,36 @@ enum {
         SNDRV_PCM_TSTAMP_TYPE_LAST = SNDRV_PCM_TSTAMP_TYPE_MONOTONIC,
 };
 
+/* channel positions */
+enum {
+        SNDRV_CHMAP_UNKNOWN = 0,
+        SNDRV_CHMAP_FL,         /* front left */
+        SNDRV_CHMAP_FC,         /* front center */
+        SNDRV_CHMAP_FR,         /* front right */
+        SNDRV_CHMAP_FLC,        /* front left center */
+        SNDRV_CHMAP_FRC,        /* front right center */
+        SNDRV_CHMAP_RL,         /* rear left */
+        SNDRV_CHMAP_RC,         /* rear center */
+        SNDRV_CHMAP_RR,         /* rear right */
+        SNDRV_CHMAP_RLC,        /* rear left center */
+        SNDRV_CHMAP_RRC,        /* rear right center */
+        SNDRV_CHMAP_SL,         /* side left */
+        SNDRV_CHMAP_SR,         /* side right */
+        SNDRV_CHMAP_LFE,        /* LFE */
+        SNDRV_CHMAP_FLW,        /* front left wide */
+        SNDRV_CHMAP_FRW,        /* front right wide */
+        SNDRV_CHMAP_FLH,        /* front left high */
+        SNDRV_CHMAP_FCH,        /* front center high */
+        SNDRV_CHMAP_FRH,        /* front right high */
+        SNDRV_CHMAP_TC,         /* top center */
+        SNDRV_CHMAP_NA,         /* N/A, silent */
+        SNDRV_CHMAP_LAST = SNDRV_CHMAP_NA,
+};
+
+#define SNDRV_CHMAP_POSITION_MASK       0xffff
+#define SNDRV_CHMAP_PHASE_INVERSE       (0x01 << 16)
+#define SNDRV_CHMAP_DRIVER_SPEC         (0x02 << 16)
+
 #define SNDRV_PCM_IOCTL_PVERSION        _IOR('A', 0x00, int)
 #define SNDRV_PCM_IOCTL_INFO            _IOR('A', 0x01, struct snd_pcm_info)
 #define SNDRV_PCM_IOCTL_TSTAMP          _IOW('A', 0x02, int)