sound/firewire/bebob/bebob_yamaha_terratec.c

   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 };