5b78efd2ef
Fixed obsolete *_t typedefs in ASoC documentation. Signed-off-by: Takashi Iwai <tiwai@suse.de> Signed-off-by: Jaroslav Kysela <perex@suse.cz>
58 lines
1.7 KiB
Text
58 lines
1.7 KiB
Text
ASoC Platform Driver
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====================
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An ASoC platform driver can be divided into audio DMA and SoC DAI configuration
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and control. The platform drivers only target the SoC CPU and must have no board
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specific code.
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Audio DMA
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=========
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The platform DMA driver optionally supports the following alsa operations:-
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/* SoC audio ops */
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struct snd_soc_ops {
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int (*startup)(struct snd_pcm_substream *);
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void (*shutdown)(struct snd_pcm_substream *);
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int (*hw_params)(struct snd_pcm_substream *, struct snd_pcm_hw_params *);
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int (*hw_free)(struct snd_pcm_substream *);
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int (*prepare)(struct snd_pcm_substream *);
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int (*trigger)(struct snd_pcm_substream *, int);
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};
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The platform driver exports it's DMA functionailty via struct snd_soc_platform:-
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struct snd_soc_platform {
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char *name;
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int (*probe)(struct platform_device *pdev);
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int (*remove)(struct platform_device *pdev);
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int (*suspend)(struct platform_device *pdev, struct snd_soc_cpu_dai *cpu_dai);
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int (*resume)(struct platform_device *pdev, struct snd_soc_cpu_dai *cpu_dai);
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/* pcm creation and destruction */
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int (*pcm_new)(struct snd_card *, struct snd_soc_codec_dai *, struct snd_pcm *);
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void (*pcm_free)(struct snd_pcm *);
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/* platform stream ops */
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struct snd_pcm_ops *pcm_ops;
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};
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Please refer to the alsa driver documentation for details of audio DMA.
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http://www.alsa-project.org/~iwai/writing-an-alsa-driver/c436.htm
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An example DMA driver is soc/pxa/pxa2xx-pcm.c
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SoC DAI Drivers
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===============
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Each SoC DAI driver must provide the following features:-
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1) Digital audio interface (DAI) description
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2) Digital audio interface configuration
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3) PCM's description
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4) Sysclk configuration
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5) Suspend and resume (optional)
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Please see codec.txt for a description of items 1 - 4.
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