1 // SPDX-License-Identifier: GPL-2.0-only
2 /*
3  * bebob_yamaha.c - a part of driver for BeBoB based devices
4  *
5  * Copyright (c) 2013-2014 Takashi Sakamoto
6  */
7 
8 #include "./bebob.h"
9 
10 /*
11  * NOTE:
12  * Yamaha GO44 is not designed to be used as stand-alone mixer. So any streams
13  * must be accompanied. If changing the state, a LED on the device starts to
14  * blink and its sync status is false. In this state, the device sounds nothing
15  * even if streaming. To start streaming at the current sampling rate is only
16  * way to recover this state. GO46 is better for stand-alone mixer.
17  *
18  * Both of them have a capability to change its sampling rate up to 192.0kHz.
19  * At 192.0kHz, the device reports 4 PCM-in, 1 MIDI-in, 6 PCM-out, 1 MIDI-out.
20  * But Yamaha's driver reduce 2 PCM-in, 1 MIDI-in, 2 PCM-out, 1 MIDI-out to use
21  * 'Extended Stream Format Information Command - Single Request' in 'Additional
22  * AVC commands' defined by BridgeCo.
23  * This ALSA driver don't do this because a bit tiresome. Then isochronous
24  * streaming with many asynchronous transactions brings sounds with noises.
25  * Unfortunately current 'ffado-mixer' generated many asynchronous transaction
26  * to observe device's state, mainly check cmp connection and signal format. I
27  * recommend users to close ffado-mixer at 192.0kHz if mixer is needless.
28  *
29  * Terratec PHASE 24 FW and PHASE X24 FW are internally the same as
30  * Yamaha GO 44 and GO 46. Yamaha and Terratec had cooperated for these models.
31  */
32 
33 static const enum snd_bebob_clock_type clk_src_types[] = {
34 	SND_BEBOB_CLOCK_TYPE_INTERNAL,
35 	SND_BEBOB_CLOCK_TYPE_EXTERNAL,	/* S/PDIF */
36 };
37 static int
38 clk_src_get(struct snd_bebob *bebob, unsigned int *id)
39 {
40 	int err;
41 
42 	err = avc_audio_get_selector(bebob->unit, 0, 4, id);
43 	if (err < 0)
44 		return err;
45 
46 	if (*id >= ARRAY_SIZE(clk_src_types))
47 		return -EIO;
48 
49 	return 0;
50 }
51 static const struct snd_bebob_clock_spec clock_spec = {
52 	.num	= ARRAY_SIZE(clk_src_types),
53 	.types	= clk_src_types,
54 	.get	= &clk_src_get,
55 };
56 static const struct snd_bebob_rate_spec rate_spec = {
57 	.get	= &snd_bebob_stream_get_rate,
58 	.set	= &snd_bebob_stream_set_rate,
59 };
60 const struct snd_bebob_spec yamaha_terratec_spec = {
61 	.clock	= &clock_spec,
62 	.rate	= &rate_spec,
63 	.meter	= NULL
64 };
65