diff options
Diffstat (limited to 'include/uapi/sound/firewire.h')
| -rw-r--r-- | include/uapi/sound/firewire.h | 30 |
1 files changed, 30 insertions, 0 deletions
diff --git a/include/uapi/sound/firewire.h b/include/uapi/sound/firewire.h index 347fd7a05596..82d4765fbeee 100644 --- a/include/uapi/sound/firewire.h +++ b/include/uapi/sound/firewire.h @@ -143,4 +143,34 @@ struct snd_firewire_motu_register_dsp_meter { __u8 data[SNDRV_FIREWIRE_MOTU_REGISTER_DSP_METER_COUNT]; }; +// In below MOTU models, software is allowed to control their DSP by command in frame of +// asynchronous transaction to 0x'ffff'0001'0000: +// +// - 828 mk3 (FireWire only and Hybrid) +// - 896 mk3 (FireWire only and Hybrid) +// - Ultralite mk3 (FireWire only and Hybrid) +// - Traveler mk3 +// - Track 16 +// +// On the other hand, the states of hardware meter is split into specific messages included in the +// sequence of isochronous packet. ALSA firewire-motu driver gathers the message and allow userspace +// application to read it via ioctl. + +#define SNDRV_FIREWIRE_MOTU_COMMAND_DSP_METER_COUNT 400 + +/** + * struct snd_firewire_motu_command_dsp_meter - the container for meter information in DSP + * controlled by command + * @data: Signal level meters. The mapping between position and signal channel is model-dependent. + * + * The structure expresses the part of DSP status for hardware meter. The 32 bit storage is + * estimated to include IEEE 764 32 bit single precision floating point (binary32) value. It is + * expected to be linear value (not logarithm) for audio signal level between 0.0 and +1.0. However, + * the last two quadlets (data[398] and data[399]) are filled with 0xffffffff since they are the + * marker of one period. + */ +struct snd_firewire_motu_command_dsp_meter { + __u32 data[SNDRV_FIREWIRE_MOTU_COMMAND_DSP_METER_COUNT]; +}; + #endif /* _UAPI_SOUND_FIREWIRE_H_INCLUDED */ |