diff options
Diffstat (limited to 'sound/firewire/amdtp-am824.c')
| -rw-r--r-- | sound/firewire/amdtp-am824.c | 42 |
1 files changed, 42 insertions, 0 deletions
diff --git a/sound/firewire/amdtp-am824.c b/sound/firewire/amdtp-am824.c index da4b643eff40..f5edcbfa3157 100644 --- a/sound/firewire/amdtp-am824.c +++ b/sound/firewire/amdtp-am824.c @@ -10,6 +10,48 @@ #define CIP_FMT_AM 0x10 +/* "Clock-based rate control mode" is just supported. */ +#define AMDTP_FDF_AM824 0x00 + +/** + * amdtp_am824_set_parameters - set stream parameters + * @s: the AMDTP stream to configure + * @rate: the sample rate + * @pcm_channels: the number of PCM samples in each data block, to be encoded + * as AM824 multi-bit linear audio + * @midi_ports: the number of MIDI ports (i.e., MPX-MIDI Data Channels) + * @double_pcm_frames: one data block transfers two PCM frames + * + * The parameters must be set before the stream is started, and must not be + * changed while the stream is running. + */ +int amdtp_am824_set_parameters(struct amdtp_stream *s, unsigned int rate, + unsigned int pcm_channels, + unsigned int midi_ports, + bool double_pcm_frames) +{ + int err; + + err = amdtp_stream_set_parameters(s, rate, pcm_channels, midi_ports); + if (err < 0) + return err; + + s->fdf = AMDTP_FDF_AM824 | s->sfc; + + /* + * In IEC 61883-6, one data block represents one event. In ALSA, one + * event equals to one PCM frame. But Dice has a quirk at higher + * sampling rate to transfer two PCM frames in one data block. + */ + if (double_pcm_frames) + s->frame_multiplier = 2; + else + s->frame_multiplier = 1; + + return 0; +} +EXPORT_SYMBOL_GPL(amdtp_am824_set_parameters); + /** * amdtp_am824_init - initialize an AMDTP stream structure to handle AM824 * data block |