Documentation/sound/soc/codec-to-codec.rst

Source file repositories/reference/linux-study-clean/Documentation/sound/soc/codec-to-codec.rst

File Facts

System: Linux kernel
Corpus path: Documentation/sound/soc/codec-to-codec.rst
Extension: .rst
Size: 3932 bytes
Lines: 116
Domain: Support Tooling And Documentation
Bucket: Documentation
Inferred role: Support Tooling And Documentation: documentation
Status: atlas-only

Why This File Exists

Repository support layer: documentation, build tooling, samples, user-space helper tools, generated initramfs support, licenses, and validation utilities.

Repository support layer: documentation, build tooling, samples, user-space helper tools, generated initramfs support, licenses, and validation utilities.
Defines or uses C structs; map object ownership, embedded links, reference counts, and lock ownership.

Dependency Surface

No C-style include directives detected by the generator.

Detected Declarations

No top-level syscall, struct, function, initcall, or export declaration detected by the generator.

Annotated Snippet

==============================================
Creating codec to codec dai link for ALSA dapm
==============================================

Mostly the flow of audio is always from CPU to codec so your system
will look as below:
::

   ---------          ---------
  |         |  dai   |         |
      CPU    ------->    codec
  |         |        |         |
   ---------          ---------

In case your system looks as below:
::

                       ---------
                      |         |
                        codec-2
                      |         |
                      ---------
                           |
                         dai-2
                           |
   ----------          ---------
  |          |  dai-1 |         |
      CPU     ------->  codec-1
  |          |        |         |
   ----------          ---------
                           |
                         dai-3
                           |
                       ---------
                      |         |
                        codec-3
                      |         |
                       ---------

Suppose codec-2 is a bluetooth chip and codec-3 is connected to
a speaker and you have a below scenario:
codec-2 will receive the audio data and the user wants to play that
audio through codec-3 without involving the CPU.This
aforementioned case is the ideal case when codec to codec
connection should be used.

Your dai_link should appear as below in your machine
file:
::

 /*
  * this pcm stream only supports 24 bit, 2 channel and
  * 48k sampling rate.
  */
 static const struct snd_soc_pcm_stream dsp_codec_params = {
        .formats = SNDRV_PCM_FMTBIT_S24_LE,
        .rate_min = 48000,
        .rate_max = 48000,
        .channels_min = 2,
        .channels_max = 2,
 };

 {
    .name = "CPU-DSP",
    .stream_name = "CPU-DSP",
    .cpu_dai_name = "samsung-i2s.0",
    .codec_name = "codec-2,
    .codec_dai_name = "codec-2-dai_name",
    .platform_name = "samsung-i2s.0",
    .dai_fmt = SND_SOC_DAIFMT_I2S | SND_SOC_DAIFMT_NB_NF

Annotation

Atlas domain: Support Tooling And Documentation / Documentation.
Implementation status: atlas-only.

Implementation Notes

This generated page is the file-by-file coverage layer; curated subsystem chapters should link here when they synthesize a multi-file control flow.
Core OS pages should be promoted from atlas-only to deep-reviewed when they explain data structures, invariants, locking, lifecycle, and C implementation snippets.
Driver-family pages are intentionally pattern-oriented unless they are part of the selected PCIe/NVMe representative device path.