diff mbox series

[v3,10/13] ASoC: tegra: Add audio graph based card driver

Message ID 1601573587-15288-11-git-send-email-spujar@nvidia.com
State Superseded
Headers show
Series Audio graph card updates and usage with Tegra210 audio | expand

Commit Message

Sameer Pujar Oct. 1, 2020, 5:33 p.m. UTC
Add Tegra audio machine driver which is based on generic audio graph card
driver. It re-uses most of the common stuff from audio graph driver and
uses the same DT binding. Required Tegra specific customizations are done
in the driver.

Details on the customizations done:

 - Update PLL rates at runtime: Tegra HW supports multiple sample rates
   (multiples of 8x and 11.025x) and both of these groups require different
   PLL rates. Hence there is a requirement to update this at runtime.
   This is achieved by providing a custom 'snd_soc_ops' and in hw_param()
   callback PLL rate is updated as per the sample rate.

 - Internal structure 'tegra_audio_graph_data' is used to maintain clock
   handles of PLL.

 - The 'force_dpcm' flag is set to use DPCM for all DAI links.

 - The 'component_chaining' flag is set to use DPCM with component model.

Signed-off-by: Sameer Pujar <spujar@nvidia.com>
---
 sound/soc/tegra/Kconfig                  |   9 +
 sound/soc/tegra/Makefile                 |   2 +
 sound/soc/tegra/tegra_audio_graph_card.c | 291 +++++++++++++++++++++++++++++++
 3 files changed, 302 insertions(+)
 create mode 100644 sound/soc/tegra/tegra_audio_graph_card.c

Comments

Michał Mirosław Oct. 1, 2020, 7:07 p.m. UTC | #1
On Thu, Oct 01, 2020 at 11:03:04PM +0530, Sameer Pujar wrote:
> Add Tegra audio machine driver which is based on generic audio graph card
> driver. It re-uses most of the common stuff from audio graph driver and
> uses the same DT binding. Required Tegra specific customizations are done
> in the driver.
[...]
> +	switch (srate) {
> +	case 11025:
> +	case 22050:
> +	case 44100:
> +	case 88200:
> +	case 176400:
> +		plla_out0_rate = chip_data->plla_out0_rates[x11_RATE];
> +		plla_rate = chip_data->plla_rates[x11_RATE];
> +		break;
> +	case 8000:
> +	case 16000:
> +	case 32000:
> +	case 48000:
> +	case 96000:
> +	case 192000:
[...]

Do you really need to enumerate the frequencies? Wouldn't just checking
srate % 11025 be enough to divide the set in two? Or just calculating
the PLLA base rate by multiplying?

Best Regards,
Michał Mirosław
Jon Hunter Oct. 1, 2020, 7:44 p.m. UTC | #2
On 01/10/2020 20:07, Michał Mirosław wrote:
> On Thu, Oct 01, 2020 at 11:03:04PM +0530, Sameer Pujar wrote:
>> Add Tegra audio machine driver which is based on generic audio graph card
>> driver. It re-uses most of the common stuff from audio graph driver and
>> uses the same DT binding. Required Tegra specific customizations are done
>> in the driver.
> [...]
>> +	switch (srate) {
>> +	case 11025:
>> +	case 22050:
>> +	case 44100:
>> +	case 88200:
>> +	case 176400:
>> +		plla_out0_rate = chip_data->plla_out0_rates[x11_RATE];
>> +		plla_rate = chip_data->plla_rates[x11_RATE];
>> +		break;
>> +	case 8000:
>> +	case 16000:
>> +	case 32000:
>> +	case 48000:
>> +	case 96000:
>> +	case 192000:
> [...]
> 
> Do you really need to enumerate the frequencies? Wouldn't just checking
> srate % 11025 be enough to divide the set in two? Or just calculating
> the PLLA base rate by multiplying?


This is quite common among other ASoC drivers from what I can see. The
PLL rate does not scale with the srate, we just use a different PLL rate
depending on if the srate is 11025 Hz or 8000 Hz based. I don't see any
need to change the above.

Cheers
Jon
Dmitry Osipenko Oct. 1, 2020, 8:57 p.m. UTC | #3
01.10.2020 20:33, Sameer Pujar пишет:
> +/* Setup PLL clock as per the given sample rate */
> +static int tegra_audio_graph_update_pll(struct snd_pcm_substream *substream,
> +					struct snd_pcm_hw_params *params)
> +{
> +	struct snd_soc_pcm_runtime *rtd = asoc_substream_to_rtd(substream);
> +	struct asoc_simple_priv *priv = snd_soc_card_get_drvdata(rtd->card);
> +	struct device *dev = rtd->card->dev;
> +	struct tegra_audio_graph_data *graph_data =
> +		(struct tegra_audio_graph_data *)priv->data;
> +	struct tegra_audio_chip_data *chip_data =
> +		(struct tegra_audio_chip_data *)of_device_get_match_data(dev);

void* doesn't need casting
Dmitry Osipenko Oct. 1, 2020, 9:02 p.m. UTC | #4
01.10.2020 23:57, Dmitry Osipenko пишет:
> 01.10.2020 20:33, Sameer Pujar пишет:
>> +/* Setup PLL clock as per the given sample rate */
>> +static int tegra_audio_graph_update_pll(struct snd_pcm_substream *substream,
>> +					struct snd_pcm_hw_params *params)
>> +{
>> +	struct snd_soc_pcm_runtime *rtd = asoc_substream_to_rtd(substream);
>> +	struct asoc_simple_priv *priv = snd_soc_card_get_drvdata(rtd->card);
>> +	struct device *dev = rtd->card->dev;
>> +	struct tegra_audio_graph_data *graph_data =
>> +		(struct tegra_audio_graph_data *)priv->data;
>> +	struct tegra_audio_chip_data *chip_data =
>> +		(struct tegra_audio_chip_data *)of_device_get_match_data(dev);
> 
> void* doesn't need casting
> 

There are several similar places in the code. Not a big deal, but this
makes code less readable than it could be.
Kuninori Morimoto Oct. 2, 2020, 5:34 a.m. UTC | #5
Hi Sameer

> Add Tegra audio machine driver which is based on generic audio graph card
> driver. It re-uses most of the common stuff from audio graph driver and
> uses the same DT binding. Required Tegra specific customizations are done
> in the driver.
(snip)
> +static const struct snd_soc_ops tegra_audio_graph_ops = {
> +	.startup	= asoc_simple_startup,
> +	.shutdown	= asoc_simple_shutdown,
> +	.hw_params	= tegra_audio_graph_hw_params,
> +};

This is just an idea,
but can we use hooks here somehow ?

	.ops_hook_pre
	.ops_hook_func
	.ops_hook_post

	if (priv->ops_hook_pre->func)
		priv->ops_hook_pre->func_pre(...);

	if (priv->ops_hook_func->func)
		priv->ops_hook_func->func(...);	/* driver's function */
	else
		graph_func(...);	/* audio-graph function */
		
	if (priv->ops_hook_post->func)
		priv->ops_hook_post->func(...);


> +static int tegra_audio_graph_probe(struct platform_device *pdev)
> +{
> +	struct asoc_simple_priv *priv;
> +	struct device *dev = &pdev->dev;
> +	struct snd_soc_card *card;
> +	struct link_info li;
> +	int err;
> +
> +	/* Allocate the private data and the DAI link array */
> +	priv = devm_kzalloc(dev, sizeof(*priv), GFP_KERNEL);
> +	if (!priv)
> +		return -ENOMEM;
> +
> +	priv->data = (struct tegra_audio_graph_data *)
> +		devm_kzalloc(dev, sizeof(*priv->data), GFP_KERNEL);
> +	if (!priv->data)
> +		return -ENOMEM;
> +
> +	card = simple_priv_to_card(priv);
> +
> +	card->owner = THIS_MODULE;
> +	card->dev = dev;
> +	card->component_chaining = true;
> +	card->probe = tegra_audio_graph_card_probe;
> +
> +	priv->ops = &tegra_audio_graph_ops;
> +	priv->force_dpcm = 1;
> +
> +	memset(&li, 0, sizeof(li));
> +	graph_get_dais_count(priv, &li);
> +	if (!li.link || !li.dais)
> +		return -EINVAL;
> +
> +	err = asoc_simple_init_priv(priv, &li);
> +	if (err < 0)
> +		return err;
> +
> +	err = graph_parse_of(priv);
> +	if (err < 0) {
> +		if (err != -EPROBE_DEFER)
> +			dev_err(dev, "Parse error %d\n", err);
> +		goto cleanup;
> +	}
> +
> +	snd_soc_card_set_drvdata(card, priv);
> +
> +	asoc_simple_debug_info(priv);
> +
> +	err = devm_snd_soc_register_card(dev, card);
> +	if (err < 0)
> +		goto cleanup;
> +
> +	return 0;
> +
> +cleanup:
> +	asoc_simple_clean_reference(card);
> +
> +	return err;
> +}

These are almost same as graph_probe().
Maybe we can separate graph_probe() and export function ?

	struct tegra_audio_graph_data
	{
		struct asoc_simple_priv simple;
		...
	};
	#define simple_to_priv(_simple) container_of((_simple), struct my_priv, simple)

	static int tegra_audio_graph_probe(struct platform_device *pdev)
	{
		struct tegra_audio_graph_data *data;
		struct asoc_simple_priv *priv;

		/* Allocate the private data */
		data = devm_kzalloc(dev, sizeof(*data), GFP_KERNEL);
		if (!data)
			return -ENOMEM;

		/* initial audio-graph */
		ret = audio_graph_init(priv, pdev);
		if (ret < 0)
			return -xxx;

		/* over-write for own settings */
		card = simple_priv_to_card(priv);
		card->component_chaining = true;
		card->probe = tegra_audio_graph_card_probe;

		priv = &data->simple;
		priv->ops_hook_pre = &tegra_audio_graph_ops;
		priv->force_dpcm = 1;

		/* audio-graph remain */
		return audio_graph_prove(priv, pdev);
	}

Thank you for your help !!

Best regards
---
Kuninori Morimoto
Sameer Pujar Oct. 2, 2020, 8:51 a.m. UTC | #6
>>> +/* Setup PLL clock as per the given sample rate */
>>> +static int tegra_audio_graph_update_pll(struct snd_pcm_substream *substream,
>>> +                                    struct snd_pcm_hw_params *params)
>>> +{
>>> +    struct snd_soc_pcm_runtime *rtd = asoc_substream_to_rtd(substream);
>>> +    struct asoc_simple_priv *priv = snd_soc_card_get_drvdata(rtd->card);
>>> +    struct device *dev = rtd->card->dev;
>>> +    struct tegra_audio_graph_data *graph_data =
>>> +            (struct tegra_audio_graph_data *)priv->data;
>>> +    struct tegra_audio_chip_data *chip_data =
>>> +            (struct tegra_audio_chip_data *)of_device_get_match_data(dev);
>> void* doesn't need casting
>>
> There are several similar places in the code. Not a big deal, but this
> makes code less readable than it could be.

I will drop these in next revision.
Sameer Pujar Oct. 2, 2020, 9:08 a.m. UTC | #7
>> Add Tegra audio machine driver which is based on generic audio graph card
>> driver. It re-uses most of the common stuff from audio graph driver and
>> uses the same DT binding. Required Tegra specific customizations are done
>> in the driver.
> (snip)
>> +static const struct snd_soc_ops tegra_audio_graph_ops = {
>> +     .startup        = asoc_simple_startup,
>> +     .shutdown       = asoc_simple_shutdown,
>> +     .hw_params      = tegra_audio_graph_hw_params,
>> +};
> This is just an idea,
> but can we use hooks here somehow ?
>
>          .ops_hook_pre
>          .ops_hook_func
>          .ops_hook_post
>
>          if (priv->ops_hook_pre->func)
>                  priv->ops_hook_pre->func_pre(...);
>
>          if (priv->ops_hook_func->func)
>                  priv->ops_hook_func->func(...); /* driver's function */
>          else
>                  graph_func(...);        /* audio-graph function */
>
>          if (priv->ops_hook_post->func)
>                  priv->ops_hook_post->func(...);

Right now I just required to populate some flags or structures and do 
not have any specific pre()/post() functions to be called. Can this be 
reserved for later?

>
>
>> +static int tegra_audio_graph_probe(struct platform_device *pdev)
>> +{
>> +     struct asoc_simple_priv *priv;
>> +     struct device *dev = &pdev->dev;
>> +     struct snd_soc_card *card;
>> +     struct link_info li;
>> +     int err;
>> +
>> +     /* Allocate the private data and the DAI link array */
>> +     priv = devm_kzalloc(dev, sizeof(*priv), GFP_KERNEL);
>> +     if (!priv)
>> +             return -ENOMEM;
>> +
>> +     priv->data = (struct tegra_audio_graph_data *)
>> +             devm_kzalloc(dev, sizeof(*priv->data), GFP_KERNEL);
>> +     if (!priv->data)
>> +             return -ENOMEM;
>> +
>> +     card = simple_priv_to_card(priv);
>> +
>> +     card->owner = THIS_MODULE;
>> +     card->dev = dev;
>> +     card->component_chaining = true;
>> +     card->probe = tegra_audio_graph_card_probe;
>> +
>> +     priv->ops = &tegra_audio_graph_ops;
>> +     priv->force_dpcm = 1;
>> +
>> +     memset(&li, 0, sizeof(li));
>> +     graph_get_dais_count(priv, &li);
>> +     if (!li.link || !li.dais)
>> +             return -EINVAL;
>> +
>> +     err = asoc_simple_init_priv(priv, &li);
>> +     if (err < 0)
>> +             return err;
>> +
>> +     err = graph_parse_of(priv);
>> +     if (err < 0) {
>> +             if (err != -EPROBE_DEFER)
>> +                     dev_err(dev, "Parse error %d\n", err);
>> +             goto cleanup;
>> +     }
>> +
>> +     snd_soc_card_set_drvdata(card, priv);
>> +
>> +     asoc_simple_debug_info(priv);
>> +
>> +     err = devm_snd_soc_register_card(dev, card);
>> +     if (err < 0)
>> +             goto cleanup;
>> +
>> +     return 0;
>> +
>> +cleanup:
>> +     asoc_simple_clean_reference(card);
>> +
>> +     return err;
>> +}

> These are almost same as graph_probe().
> Maybe we can separate graph_probe() and export function ?

Yes possible, I can move more stuff into graph_parse_of() which is 
already an exported function in the current series. This can be utilized 
by both generic audio graph and Tegra audio graph.

Something like below,

static int tegra_audio_graph_probe(struct platform_device *pdev)
{
         struct tegra_audio_priv *priv;
         struct device *dev = &pdev->dev;
         struct snd_soc_card *card;

         priv = devm_kzalloc(dev, sizeof(*priv), GFP_KERNEL);
         if (!priv)
                 return -ENOMEM;

         card = simple_priv_to_card(&priv->simple);

         card->owner = THIS_MODULE;
         card->dev = dev;
         card->probe = tegra_audio_graph_card_probe;

         /* graph_parse_of() depends on below */
         card->component_chaining = 1;
         priv->simple.ops = &tegra_audio_graph_ops;
         priv->simple.force_dpcm = 1;

         return graph_parse_of(&priv->simple);
}

Does this sound fine?
Kuninori Morimoto Oct. 4, 2020, 11:20 p.m. UTC | #8
Hi Sameer

> > This is just an idea,
> > but can we use hooks here somehow ?
> > 
> >          .ops_hook_pre
> >          .ops_hook_func
> >          .ops_hook_post
> > 
> >          if (priv->ops_hook_pre->func)
> >                  priv->ops_hook_pre->func_pre(...);
> > 
> >          if (priv->ops_hook_func->func)
> >                  priv->ops_hook_func->func(...); /* driver's function */
> >          else
> >                  graph_func(...);        /* audio-graph function */
> > 
> >          if (priv->ops_hook_post->func)
> >                  priv->ops_hook_post->func(...);
> 
> Right now I just required to populate some flags or structures and do
> not have any specific pre()/post() functions to be called. Can this be
> reserved for later?

Yeah, of course :)

> > These are almost same as graph_probe().
> > Maybe we can separate graph_probe() and export function ?
> 
> Yes possible, I can move more stuff into graph_parse_of() which is
> already an exported function in the current series. This can be
> utilized by both generic audio graph and Tegra audio graph.
> 
> Something like below,
> 
> static int tegra_audio_graph_probe(struct platform_device *pdev)
> {
>         struct tegra_audio_priv *priv;
>         struct device *dev = &pdev->dev;
>         struct snd_soc_card *card;
> 
>         priv = devm_kzalloc(dev, sizeof(*priv), GFP_KERNEL);
>         if (!priv)
>                 return -ENOMEM;
> 
>         card = simple_priv_to_card(&priv->simple);
> 
>         card->owner = THIS_MODULE;
>         card->dev = dev;
>         card->probe = tegra_audio_graph_card_probe;
> 
>         /* graph_parse_of() depends on below */
>         card->component_chaining = 1;
>         priv->simple.ops = &tegra_audio_graph_ops;
>         priv->simple.force_dpcm = 1;
> 
>         return graph_parse_of(&priv->simple);
> }

I think graph side can handle card->owner / card->dev,
but, it looks good to me

Thank you for your help !!

Best regards
---
Kuninori Morimoto
diff mbox series

Patch

diff --git a/sound/soc/tegra/Kconfig b/sound/soc/tegra/Kconfig
index 3d91bd3..9959605 100644
--- a/sound/soc/tegra/Kconfig
+++ b/sound/soc/tegra/Kconfig
@@ -118,6 +118,15 @@  config SND_SOC_TEGRA210_ADMAIF
 	  channel. Buffer size is configurable for each ADMAIIF channel.
 	  Say Y or M if you want to add support for Tegra210 ADMAIF module.
 
+config SND_SOC_TEGRA_AUDIO_GRAPH_CARD
+	tristate "Audio Graph Card based Tegra driver"
+	depends on SND_AUDIO_GRAPH_CARD
+	help
+	  Config to enable Tegra audio machine driver based on generic
+	  audio graph driver. It is a thin driver written to customize
+	  few things for Tegra audio. Most of the code is re-used from
+	  audio graph driver and the same DT bindings are used.
+
 config SND_SOC_TEGRA_RT5640
 	tristate "SoC Audio support for Tegra boards using an RT5640 codec"
 	depends on SND_SOC_TEGRA && I2C && GPIOLIB
diff --git a/sound/soc/tegra/Makefile b/sound/soc/tegra/Makefile
index 60040a0..b17dd6e 100644
--- a/sound/soc/tegra/Makefile
+++ b/sound/soc/tegra/Makefile
@@ -38,6 +38,7 @@  snd-soc-tegra-trimslice-objs := trimslice.o
 snd-soc-tegra-alc5632-objs := tegra_alc5632.o
 snd-soc-tegra-max98090-objs := tegra_max98090.o
 snd-soc-tegra-sgtl5000-objs := tegra_sgtl5000.o
+snd-soc-tegra-audio-graph-card-objs := tegra_audio_graph_card.o
 
 obj-$(CONFIG_SND_SOC_TEGRA_RT5640) += snd-soc-tegra-rt5640.o
 obj-$(CONFIG_SND_SOC_TEGRA_RT5677) += snd-soc-tegra-rt5677.o
@@ -48,3 +49,4 @@  obj-$(CONFIG_SND_SOC_TEGRA_TRIMSLICE) += snd-soc-tegra-trimslice.o
 obj-$(CONFIG_SND_SOC_TEGRA_ALC5632) += snd-soc-tegra-alc5632.o
 obj-$(CONFIG_SND_SOC_TEGRA_MAX98090) += snd-soc-tegra-max98090.o
 obj-$(CONFIG_SND_SOC_TEGRA_SGTL5000) += snd-soc-tegra-sgtl5000.o
+obj-$(CONFIG_SND_SOC_TEGRA_AUDIO_GRAPH_CARD) += snd-soc-tegra-audio-graph-card.o
diff --git a/sound/soc/tegra/tegra_audio_graph_card.c b/sound/soc/tegra/tegra_audio_graph_card.c
new file mode 100644
index 0000000..cfbd3f0
--- /dev/null
+++ b/sound/soc/tegra/tegra_audio_graph_card.c
@@ -0,0 +1,291 @@ 
+// SPDX-License-Identifier: GPL-2.0-only
+//
+// tegra_audio_graph_card.c - Audio Graph based Tegra Machine Driver
+//
+// Copyright (c) 2020 NVIDIA CORPORATION.  All rights reserved.
+
+#include <linux/math64.h>
+#include <linux/module.h>
+#include <linux/of_device.h>
+#include <linux/platform_device.h>
+#include <sound/graph_card.h>
+#include <sound/pcm_params.h>
+
+#define MAX_PLLA_OUT0_DIV 128
+
+enum srate_type {
+	/*
+	 * Sample rates multiple of 8000 Hz and below are supported:
+	 * ( 8000, 16000, 32000, 48000, 96000, 192000 Hz )
+	 */
+	x8_RATE,
+
+	/*
+	 * Sample rates multiple of 11025 Hz and below are supported:
+	 * ( 11025, 22050, 44100, 88200, 176400 Hz )
+	 */
+	x11_RATE,
+
+	NUM_RATE_TYPE,
+};
+
+struct tegra_audio_graph_data {
+	struct clk *clk_plla_out0;
+	struct clk *clk_plla;
+};
+
+struct tegra_audio_chip_data {
+	unsigned int plla_out0_rates[NUM_RATE_TYPE];
+	unsigned int plla_rates[NUM_RATE_TYPE];
+};
+
+/* Setup PLL clock as per the given sample rate */
+static int tegra_audio_graph_update_pll(struct snd_pcm_substream *substream,
+					struct snd_pcm_hw_params *params)
+{
+	struct snd_soc_pcm_runtime *rtd = asoc_substream_to_rtd(substream);
+	struct asoc_simple_priv *priv = snd_soc_card_get_drvdata(rtd->card);
+	struct device *dev = rtd->card->dev;
+	struct tegra_audio_graph_data *graph_data =
+		(struct tegra_audio_graph_data *)priv->data;
+	struct tegra_audio_chip_data *chip_data =
+		(struct tegra_audio_chip_data *)of_device_get_match_data(dev);
+	unsigned int srate = params_rate(params);
+	unsigned int plla_rate, plla_out0_rate, bclk;
+	int err;
+
+	/* There is nothing to configure */
+	if (!chip_data)
+		return 0;
+
+	switch (srate) {
+	case 11025:
+	case 22050:
+	case 44100:
+	case 88200:
+	case 176400:
+		plla_out0_rate = chip_data->plla_out0_rates[x11_RATE];
+		plla_rate = chip_data->plla_rates[x11_RATE];
+		break;
+	case 8000:
+	case 16000:
+	case 32000:
+	case 48000:
+	case 96000:
+	case 192000:
+		plla_out0_rate = chip_data->plla_out0_rates[x8_RATE];
+		plla_rate = chip_data->plla_rates[x8_RATE];
+		break;
+	default:
+		dev_err(rtd->card->dev, "Unsupported sample rate %u\n",
+			srate);
+		return -EINVAL;
+	}
+
+	/*
+	 * Below is the clock relation:
+	 *
+	 *	PLLA
+	 *	  |
+	 *	  |--> PLLA_OUT0
+	 *		  |
+	 *		  |---> I2S modules
+	 *		  |
+	 *		  |---> DMIC modules
+	 *		  |
+	 *		  |---> DSPK modules
+	 *
+	 *
+	 * Default PLLA_OUT0 rate might be too high when I/O is running
+	 * at minimum PCM configurations. This may result in incorrect
+	 * clock rates and glitchy audio. The maximum divider is 128
+	 * and any thing higher than that won't work. Thus reduce PLLA_OUT0
+	 * to work for lower configurations.
+	 *
+	 * This problem is seen for I2S only, as DMIC and DSPK minimum
+	 * clock requirements are under allowed divider limits.
+	 */
+	bclk = srate * params_channels(params) * params_width(params);
+	if (div_u64(plla_out0_rate, bclk) > MAX_PLLA_OUT0_DIV)
+		plla_out0_rate >>= 1;
+
+	dev_dbg(rtd->card->dev,
+		"Update clock rates: PLLA(= %u Hz) and PLLA_OUT0(= %u Hz)\n",
+		plla_rate, plla_out0_rate);
+
+	/* Set PLLA rate */
+	err = clk_set_rate(graph_data->clk_plla, plla_rate);
+	if (err) {
+		dev_err(rtd->card->dev,
+			"Can't set plla rate for %u, err: %d\n",
+			plla_rate, err);
+		return err;
+	}
+
+	/* Set PLLA_OUT0 rate */
+	err = clk_set_rate(graph_data->clk_plla_out0, plla_out0_rate);
+	if (err) {
+		dev_err(rtd->card->dev,
+			"Can't set plla_out0 rate %u, err: %d\n",
+			plla_out0_rate, err);
+		return err;
+	}
+
+	return err;
+}
+
+static int tegra_audio_graph_hw_params(struct snd_pcm_substream *substream,
+				       struct snd_pcm_hw_params *params)
+{
+	struct snd_soc_pcm_runtime *rtd = asoc_substream_to_rtd(substream);
+	struct snd_soc_dai *cpu_dai = asoc_rtd_to_cpu(rtd, 0);
+	int err;
+
+	/*
+	 * This gets called for each DAI link (FE or BE) when DPCM is used.
+	 * We may not want to update PLLA rate for each call. So PLLA update
+	 * must be restricted to external I/O links (I2S, DMIC or DSPK) since
+	 * they actually depend on it. I/O modules update their clocks in
+	 * hw_param() of their respective component driver and PLLA rate
+	 * update here helps them to derive appropriate rates.
+	 *
+	 * TODO: When more HW accelerators get added (like sample rate
+	 * converter, volume gain controller etc., which don't really
+	 * depend on PLLA) we need a better way to filter here.
+	 */
+	if (cpu_dai->driver->ops && rtd->dai_link->no_pcm) {
+		err = tegra_audio_graph_update_pll(substream, params);
+		if (err)
+			return err;
+	}
+
+	return asoc_simple_hw_params(substream, params);
+}
+
+static const struct snd_soc_ops tegra_audio_graph_ops = {
+	.startup	= asoc_simple_startup,
+	.shutdown	= asoc_simple_shutdown,
+	.hw_params	= tegra_audio_graph_hw_params,
+};
+
+static int tegra_audio_graph_card_probe(struct snd_soc_card *card)
+{
+	struct asoc_simple_priv *priv = snd_soc_card_get_drvdata(card);
+	struct tegra_audio_graph_data *graph_data =
+		(struct tegra_audio_graph_data *)priv->data;
+
+	graph_data->clk_plla = devm_clk_get(card->dev, "pll_a");
+	if (IS_ERR(graph_data->clk_plla)) {
+		dev_err(card->dev, "Can't retrieve clk pll_a\n");
+		return PTR_ERR(graph_data->clk_plla);
+	}
+
+	graph_data->clk_plla_out0 = devm_clk_get(card->dev, "plla_out0");
+	if (IS_ERR(graph_data->clk_plla_out0)) {
+		dev_err(card->dev, "Can't retrieve clk plla_out0\n");
+		return PTR_ERR(graph_data->clk_plla_out0);
+	}
+
+	return graph_card_probe(card);
+}
+
+static int tegra_audio_graph_probe(struct platform_device *pdev)
+{
+	struct asoc_simple_priv *priv;
+	struct device *dev = &pdev->dev;
+	struct snd_soc_card *card;
+	struct link_info li;
+	int err;
+
+	/* Allocate the private data and the DAI link array */
+	priv = devm_kzalloc(dev, sizeof(*priv), GFP_KERNEL);
+	if (!priv)
+		return -ENOMEM;
+
+	priv->data = (struct tegra_audio_graph_data *)
+		devm_kzalloc(dev, sizeof(*priv->data), GFP_KERNEL);
+	if (!priv->data)
+		return -ENOMEM;
+
+	card = simple_priv_to_card(priv);
+
+	card->owner = THIS_MODULE;
+	card->dev = dev;
+	card->component_chaining = true;
+	card->probe = tegra_audio_graph_card_probe;
+
+	priv->ops = &tegra_audio_graph_ops;
+	priv->force_dpcm = 1;
+
+	memset(&li, 0, sizeof(li));
+	graph_get_dais_count(priv, &li);
+	if (!li.link || !li.dais)
+		return -EINVAL;
+
+	err = asoc_simple_init_priv(priv, &li);
+	if (err < 0)
+		return err;
+
+	err = graph_parse_of(priv);
+	if (err < 0) {
+		if (err != -EPROBE_DEFER)
+			dev_err(dev, "Parse error %d\n", err);
+		goto cleanup;
+	}
+
+	snd_soc_card_set_drvdata(card, priv);
+
+	asoc_simple_debug_info(priv);
+
+	err = devm_snd_soc_register_card(dev, card);
+	if (err < 0)
+		goto cleanup;
+
+	return 0;
+
+cleanup:
+	asoc_simple_clean_reference(card);
+
+	return err;
+}
+
+static const struct tegra_audio_chip_data tegra210_data = {
+	/* PLLA */
+	.plla_rates[x8_RATE] = 368640000,
+	.plla_rates[x11_RATE] = 338688000,
+	/* PLLA_OUT0 */
+	.plla_out0_rates[x8_RATE] = 49152000,
+	.plla_out0_rates[x11_RATE] = 45158400,
+};
+
+static const struct tegra_audio_chip_data tegra186_data = {
+	/* PLLA */
+	.plla_rates[x8_RATE] = 245760000,
+	.plla_rates[x11_RATE] = 270950400,
+	/* PLLA_OUT0 */
+	.plla_out0_rates[x8_RATE] = 49152000,
+	.plla_out0_rates[x11_RATE] = 45158400,
+};
+
+static const struct of_device_id graph_of_tegra_match[] = {
+	{ .compatible = "nvidia,tegra210-audio-graph-card",
+	  .data = &tegra210_data },
+	{ .compatible = "nvidia,tegra186-audio-graph-card",
+	  .data = &tegra186_data },
+	{},
+};
+MODULE_DEVICE_TABLE(of, graph_of_tegra_match);
+
+static struct platform_driver tegra_audio_graph_card = {
+	.driver = {
+		.name = "tegra-audio-graph-card",
+		.pm = &snd_soc_pm_ops,
+		.of_match_table = graph_of_tegra_match,
+	},
+	.probe = tegra_audio_graph_probe,
+};
+module_platform_driver(tegra_audio_graph_card);
+
+MODULE_LICENSE("GPL v2");
+MODULE_DESCRIPTION("ASoC Tegra Audio Graph Sound Card");
+MODULE_AUTHOR("Sameer Pujar <spujar@nvidia.com>");