Platform of ASoC framework driven by alsa

One 、 register cpu_dai

I said before. machine Is the connection platform and Codec The bridge , stay machine In the chapter zx297520v3_nau8810_dai_link There is cpu_dai_name and platform_name, as follows ：

static struct snd_soc_dai_link zx297520v3_nau8810_dai_link[] =
{
    
	{
    
		.name = "NAU8810_Media",
		.stream_name = "MultiMedia",
		.codec_name = "nau8810.1-001a", //nau8810.1-001a
		.codec_dai_name = "nau8810-hifi",
		.cpu_dai_name = "MultiMedia",
		.ops = &zx297520v3_nau8810_ops,
		.init = zx297520v3_nau8810_init_paiftx,
		.platform_name	= "zx29-pcm-audio",
	},
	{
    
		.name = "voice_call",
		.stream_name = "voice",
		.codec_name = "nau8810.1-001a",
		.codec_dai_name = "nau8810-hifi",
		.cpu_dai_name = "voice", //"snd-soc-dummy-dai",
		.platform_name	= "snd-soc-dummy",
		.init = zx297520v3_nau8810_init_paiftx,
		.ops = &zx297520v3_nau8810_ops1,
	}
};

Search in code engineering cpu_dai_name “MultiMedia”, stay zx29_i2s.c Find snd_soc_dai_driver Structure ：

static struct snd_soc_dai_driver zx_i2s_dais[] = {
    
	{
    
		.name = "MultiMedia",
		.probe	= zx29_i2s_dai_probe,
		.suspend = zx29_i2s_suspend,
		.resume = zx29_i2s_resume,
		.playback   = {
    
			.stream_name = "MultiMedia Playback",
			.channels_min	= 1,
			.channels_max	= 8,
			.rates		= ZX29_I2S_RATES,
			.formats	= ZX29_I2S_FMTBIT,
		},
		.capture = {
    
			.stream_name = "MultiMedia Capture",
			.channels_min	= 1,
			.channels_max	= 2,
			.rates		= ZX29_I2S_RATES,
			.formats	= ZX29_I2S_FMTBIT,
		},
		.ops	= &zx29_i2s_dai_ops,
	},
	{
    
		.name = "voice",
		.probe = zx29_i2s_dai_probe1,
		.playback = {
    
			.stream_name = "voice Playback",
			.rates = ZX29_I2S_RATES,
			.formats = ZX29_I2S_FMTBIT,
			.channels_min = 1,
			.channels_max = 2,
		},
		.capture = {
    
			.stream_name = "voice Capture",
			.rates = ZX29_I2S_RATES,
			.formats = ZX29_I2S_FMTBIT,
			.channels_min = 1,
			.channels_max = 2,
		},
	}
};

snd_soc_dai_driver Structure ops Point to snd_soc_dai_ops structure , Used to configure and control the dai;playback snd_soc_pcm_stream structure , Used to indicate the dai Number of channels supported , Bit rate , Data format and other capabilities ;capture snd_soc_pcm_stream structure , Used to indicate the dai Number of channels supported , Bit rate , Data format and other capabilities ;

snd_soc_dai_ops Examples are as follows ,

static const struct snd_soc_dai_ops zx29_i2s_dai_ops = {
    
	.trigger	= zx29_i2s_trigger,
	.hw_params	= zx29_i2s_hw_params,
	.set_fmt	= zx29_i2s_set_fmt,
	.set_sysclk = zx29_i2s_set_sysclk,
	.startup	= zx29_i2s_startup,
	.shutdown	= zx29_i2s_shutdown,
};

trigger: The beginning of data transmission , Pause , When resuming and stopping , This function will be called .
hw_params: Driven hw_params Stage , This function will be called .
set_fmt: Set up dai The format of
set_sysclk: Set up dai The master clock of

Look at the registration as a whole cpu_dai The process is as follows , adopt snd_soc_register_dais Just put the above snd_soc_dai_driver zx_i2s_dais It's connected
zx29_i2s_dev_probe
—>snd_soc_register_dais

static __devinit int zx29_i2s_dev_probe(struct platform_device *pdev)
{
    
... ...
	return snd_soc_register_dais(&pdev->dev, zx_i2s_dais, ARRAY_SIZE(zx_i2s_dais));
}

static struct platform_driver zx29_i2s_driver = {
    
	.probe  = zx29_i2s_dev_probe,
	.remove = __devexit_p(zx29_i2s_dev_remove),
	.driver = {
    
		.name = "zx29_i2s",
		.owner = THIS_MODULE,
	},
};

Two 、 register platform

Search in code engineering platform_name"zx29-pcm-audio", stay zx29_pcm.c Found in file platform_driver asoc_dma_driver as follows ：

static int __devinit zx29_asoc_platform_probe(struct platform_device *pdev)
{
    
	return snd_soc_register_platform(&pdev->dev, &zx_asoc_platform);
}

static int __devexit zx29_asoc_platform_remove(struct platform_device *pdev)
{
    
	snd_soc_unregister_platform(&pdev->dev);
	return 0;
}

static struct platform_driver asoc_dma_driver = {
    
	.driver = {
    
		.name = "zx29-pcm-audio",
		.owner = THIS_MODULE,
	},
	.probe = zx29_asoc_platform_probe,
	.remove = __devexit_p(zx29_asoc_platform_remove),
};

In addition to here snd_soc_register_platform Function registration platform Outside , Also pay attention to snd_soc_platform_driver zx_asoc_platform as follows ：

static struct snd_soc_platform_driver zx_asoc_platform = {
    
	.ops		= &dma_ops,
	.pcm_new	= zx29_dma_new,
	.pcm_free	= zx29_dma_free_dma_buffers,
};

static struct snd_pcm_ops dma_ops = {
    
	.open		= zx29_dma_open,
	.close		= zx29_dma_close,
	.ioctl		= snd_pcm_lib_ioctl,
	.hw_params	= zx29_dma_hw_params,
	.hw_free	= zx29_dma_hw_free,
	.prepare	= zx29_dma_prepare,
	.trigger	= zx29_dma_trigger,
	.pointer	= zx29_dma_pointer,
	.mmap		= zx29_dma_mmap,
};

about DMA Application for interpretation 、 Put into use pcm_new、pcm_free, For configuring and starting the transfer, use dma_ops Set of operation functions to complete .
thus ALSA drive asoc Framework machine、ALSA drive asoc Framework Codec、 And this chapter ALSA drive asoc Framework Platform That's it .