Create channel-mapping control elements
int snd_pcm_add_chmap_ctls(struct snd_pcm * pcm, int stream, const struct snd_pcm_chmap_elem * chmap, int max_channels, unsigned long private_value, struct snd_pcm_chmap ** info_ret);
pcm
the assigned PCM instance
stream
stream direction
chmap
channel map elements (for query)
max_channels
the max number of channels for the stream
private_value
the value passed to each kcontrol's private_value field
info_ret
store struct snd_pcm_chmap instance if non-NULL
Create channel-mapping control elements assigned to the given PCM stream(s).
Zero if successful, or a negative error value.