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kernel add
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/*
* bebob_yamaha.c - a part of driver for BeBoB based devices
*
* Copyright (c) 2013-2014 Takashi Sakamoto
*
* Licensed under the terms of the GNU General Public License, version 2.
*/
#include "./bebob.h"
/*
* NOTE:
* Yamaha GO44 is not designed to be used as stand-alone mixer. So any streams
* must be accompanied. If changing the state, a LED on the device starts to
* blink and its sync status is false. In this state, the device sounds nothing
* even if streaming. To start streaming at the current sampling rate is only
* way to revocer this state. GO46 is better for stand-alone mixer.
*
* Both of them have a capability to change its sampling rate up to 192.0kHz.
* At 192.0kHz, the device reports 4 PCM-in, 1 MIDI-in, 6 PCM-out, 1 MIDI-out.
* But Yamaha's driver reduce 2 PCM-in, 1 MIDI-in, 2 PCM-out, 1 MIDI-out to use
* 'Extended Stream Format Information Command - Single Request' in 'Additional
* AVC commands' defined by BridgeCo.
* This ALSA driver don't do this because a bit tiresome. Then isochronous
* streaming with many asynchronous transactions brings sounds with noises.
* Unfortunately current 'ffado-mixer' generated many asynchronous transaction
* to observe device's state, mainly check cmp connection and signal format. I
* reccomend users to close ffado-mixer at 192.0kHz if mixer is needless.
*/
static enum snd_bebob_clock_type clk_src_types[] = {
SND_BEBOB_CLOCK_TYPE_INTERNAL,
SND_BEBOB_CLOCK_TYPE_EXTERNAL, /* S/PDIF */
};
static int
clk_src_get(struct snd_bebob *bebob, unsigned int *id)
{
int err;
err = avc_audio_get_selector(bebob->unit, 0, 4, id);
if (err < 0)
return err;
if (*id >= ARRAY_SIZE(clk_src_types))
return -EIO;
return 0;
}
static const struct snd_bebob_clock_spec clock_spec = {
.num = ARRAY_SIZE(clk_src_types),
.types = clk_src_types,
.get = &clk_src_get,
};
static const struct snd_bebob_rate_spec rate_spec = {
.get = &snd_bebob_stream_get_rate,
.set = &snd_bebob_stream_set_rate,
};
const struct snd_bebob_spec yamaha_go_spec = {
.clock = &clock_spec,
.rate = &rate_spec,
.meter = NULL
};
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