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