auclnt_get_gain
uint8_t auclnt_get_gain(audio_stream_t *);
vol = auclnt_get_gain(auclnt_output_stream(c));
vol = auclnt_get_gain(auclnt_input_stream(c));
(auclnt_get_gain(sp) * AUDIO_MAX_GAIN) / 100;
(auclnt_get_gain(sp) * AUDIO_MAX_GAIN) / 100;