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Diffstat (limited to 'Documentation/sound/alsa/soc/platform.txt')
| -rw-r--r-- | Documentation/sound/alsa/soc/platform.txt | 58 |
1 files changed, 58 insertions, 0 deletions
diff --git a/Documentation/sound/alsa/soc/platform.txt b/Documentation/sound/alsa/soc/platform.txt new file mode 100644 index 0000000..c88df26 --- /dev/null +++ b/Documentation/sound/alsa/soc/platform.txt @@ -0,0 +1,58 @@ +ASoC Platform Driver +==================== + +An ASoC platform driver can be divided into audio DMA and SoC DAI configuration +and control. 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)(snd_pcm_substream_t *); + void (*shutdown)(snd_pcm_substream_t *); + int (*hw_params)(snd_pcm_substream_t *, snd_pcm_hw_params_t *); + int (*hw_free)(snd_pcm_substream_t *); + int (*prepare)(snd_pcm_substream_t *); + int (*trigger)(snd_pcm_substream_t *, int); +}; + +The platform driver exports it's DMA functionailty via struct snd_soc_platform:- + +struct snd_soc_platform { + 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)(snd_card_t *, struct snd_soc_codec_dai *, snd_pcm_t *); + void (*pcm_free)(snd_pcm_t *); + + /* platform stream ops */ + snd_pcm_ops_t *pcm_ops; +}; + +Please refer to the alsa driver documentation for details of audio DMA. +http://www.alsa-project.org/~iwai/writing-an-alsa-driver/c436.htm + +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. |