diff options
author | Jonathan Corbet <corbet@lwn.net> | 2016-11-18 16:19:28 -0700 |
---|---|---|
committer | Jonathan Corbet <corbet@lwn.net> | 2016-11-18 16:19:28 -0700 |
commit | 726d661fea3e3f76d36515c74e4ce58e7789418e (patch) | |
tree | 0f996a1d5c0cca796b135378beb66e9829fae854 /Documentation/sound/soc/platform.rst | |
parent | Merge tag 'v4.9-rc4' into sound (diff) | |
parent | ASoC: doc: ReSTize codec_to_codec.txt (diff) | |
download | linux-dev-726d661fea3e3f76d36515c74e4ce58e7789418e.tar.xz linux-dev-726d661fea3e3f76d36515c74e4ce58e7789418e.zip |
Merge remote-tracking branch 'sound/topic/restize-docs' into sound
Bring in the sphinxification of the sound documentation.
Diffstat (limited to 'Documentation/sound/soc/platform.rst')
-rw-r--r-- | Documentation/sound/soc/platform.rst | 82 |
1 files changed, 82 insertions, 0 deletions
diff --git a/Documentation/sound/soc/platform.rst b/Documentation/sound/soc/platform.rst new file mode 100644 index 000000000000..d5574904d981 --- /dev/null +++ b/Documentation/sound/soc/platform.rst @@ -0,0 +1,82 @@ +==================== +ASoC Platform Driver +==================== + +An ASoC platform driver class can be divided into audio DMA drivers, SoC DAI +drivers and DSP drivers. The platform drivers only target the SoC CPU and must +have no board specific code. + +Audio DMA +========= + +The platform DMA driver optionally supports the following ALSA operations:- +:: + + /* SoC audio ops */ + struct snd_soc_ops { + int (*startup)(struct snd_pcm_substream *); + void (*shutdown)(struct snd_pcm_substream *); + int (*hw_params)(struct snd_pcm_substream *, struct snd_pcm_hw_params *); + int (*hw_free)(struct snd_pcm_substream *); + int (*prepare)(struct snd_pcm_substream *); + int (*trigger)(struct snd_pcm_substream *, int); + }; + +The platform driver exports its DMA functionality via struct +snd_soc_platform_driver:- +:: + + struct snd_soc_platform_driver { + char *name; + + int (*probe)(struct platform_device *pdev); + int (*remove)(struct platform_device *pdev); + int (*suspend)(struct platform_device *pdev, struct snd_soc_cpu_dai *cpu_dai); + int (*resume)(struct platform_device *pdev, struct snd_soc_cpu_dai *cpu_dai); + + /* pcm creation and destruction */ + int (*pcm_new)(struct snd_card *, struct snd_soc_codec_dai *, struct snd_pcm *); + void (*pcm_free)(struct snd_pcm *); + + /* + * For platform caused delay reporting. + * Optional. + */ + snd_pcm_sframes_t (*delay)(struct snd_pcm_substream *, + struct snd_soc_dai *); + + /* platform stream ops */ + struct snd_pcm_ops *pcm_ops; + }; + +Please refer to the ALSA driver documentation for details of audio DMA. +http://www.alsa-project.org/~iwai/writing-an-alsa-driver/ + +An example DMA driver is soc/pxa/pxa2xx-pcm.c + + +SoC DAI Drivers +=============== + +Each SoC DAI driver must provide the following features:- + +1. Digital audio interface (DAI) description +2. Digital audio interface configuration +3. PCM's description +4. SYSCLK configuration +5. Suspend and resume (optional) + +Please see codec.txt for a description of items 1 - 4. + + +SoC DSP Drivers +=============== + +Each SoC DSP driver usually supplies the following features :- + +1. DAPM graph +2. Mixer controls +3. DMA IO to/from DSP buffers (if applicable) +4. Definition of DSP front end (FE) PCM devices. + +Please see DPCM.txt for a description of item 4. |