| Takashi Sakamoto | 5955815 | 2015-09-19 11:21:55 +0900 | [diff] [blame] | 1 | /* |
| 2 | * AM824 format in Audio and Music Data Transmission Protocol (IEC 61883-6) |
| 3 | * |
| 4 | * Copyright (c) 2015 Takashi Sakamoto <o-takashi@sakamocchi.jp> |
| 5 | * |
| 6 | * Licensed under the terms of the GNU General Public License, version 2. |
| 7 | */ |
| 8 | |
| 9 | #include "amdtp-am824.h" |
| 10 | |
| 11 | #define CIP_FMT_AM 0x10 |
| 12 | |
| Takashi Sakamoto | 51c29fd | 2015-09-19 11:21:56 +0900 | [diff] [blame^] | 13 | /* "Clock-based rate control mode" is just supported. */ |
| 14 | #define AMDTP_FDF_AM824 0x00 |
| 15 | |
| 16 | /** |
| 17 | * amdtp_am824_set_parameters - set stream parameters |
| 18 | * @s: the AMDTP stream to configure |
| 19 | * @rate: the sample rate |
| 20 | * @pcm_channels: the number of PCM samples in each data block, to be encoded |
| 21 | * as AM824 multi-bit linear audio |
| 22 | * @midi_ports: the number of MIDI ports (i.e., MPX-MIDI Data Channels) |
| 23 | * @double_pcm_frames: one data block transfers two PCM frames |
| 24 | * |
| 25 | * The parameters must be set before the stream is started, and must not be |
| 26 | * changed while the stream is running. |
| 27 | */ |
| 28 | int amdtp_am824_set_parameters(struct amdtp_stream *s, unsigned int rate, |
| 29 | unsigned int pcm_channels, |
| 30 | unsigned int midi_ports, |
| 31 | bool double_pcm_frames) |
| 32 | { |
| 33 | int err; |
| 34 | |
| 35 | err = amdtp_stream_set_parameters(s, rate, pcm_channels, midi_ports); |
| 36 | if (err < 0) |
| 37 | return err; |
| 38 | |
| 39 | s->fdf = AMDTP_FDF_AM824 | s->sfc; |
| 40 | |
| 41 | /* |
| 42 | * In IEC 61883-6, one data block represents one event. In ALSA, one |
| 43 | * event equals to one PCM frame. But Dice has a quirk at higher |
| 44 | * sampling rate to transfer two PCM frames in one data block. |
| 45 | */ |
| 46 | if (double_pcm_frames) |
| 47 | s->frame_multiplier = 2; |
| 48 | else |
| 49 | s->frame_multiplier = 1; |
| 50 | |
| 51 | return 0; |
| 52 | } |
| 53 | EXPORT_SYMBOL_GPL(amdtp_am824_set_parameters); |
| 54 | |
| Takashi Sakamoto | 5955815 | 2015-09-19 11:21:55 +0900 | [diff] [blame] | 55 | /** |
| 56 | * amdtp_am824_init - initialize an AMDTP stream structure to handle AM824 |
| 57 | * data block |
| 58 | * @s: the AMDTP stream to initialize |
| 59 | * @unit: the target of the stream |
| 60 | * @dir: the direction of stream |
| 61 | * @flags: the packet transmission method to use |
| 62 | */ |
| 63 | int amdtp_am824_init(struct amdtp_stream *s, struct fw_unit *unit, |
| 64 | enum amdtp_stream_direction dir, enum cip_flags flags) |
| 65 | { |
| 66 | return amdtp_stream_init(s, unit, dir, flags, CIP_FMT_AM); |
| 67 | } |
| 68 | EXPORT_SYMBOL_GPL(amdtp_am824_init); |