Patchwork [v2,1/3] ASoC: tegra: add ac97 host driver

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Submitter Lucas Stach
Date Jan. 5, 2013, 1:18 a.m.
Message ID <1357348725-32139-2-git-send-email-dev@lynxeye.de>
Download mbox | patch
Permalink /patch/209589/
State Not Applicable, archived
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Comments

Lucas Stach - Jan. 5, 2013, 1:18 a.m.
This adds the driver for the Tegra 2x AC97 host controller.

Signed-off-by: Lucas Stach <dev@lynxeye.de>
---
v2:
- squash DT binding file into this patch
- various small fixups all over
---
 .../bindings/sound/nvidia,tegra20-ac97.txt         |  22 +
 sound/soc/tegra/Kconfig                            |  10 +
 sound/soc/tegra/Makefile                           |   2 +
 sound/soc/tegra/tegra20_ac97.c                     | 480 +++++++++++++++++++++
 sound/soc/tegra/tegra20_ac97.h                     |  95 ++++
 5 files changed, 609 insertions(+)
 create mode 100644 Documentation/devicetree/bindings/sound/nvidia,tegra20-ac97.txt
 create mode 100644 sound/soc/tegra/tegra20_ac97.c
 create mode 100644 sound/soc/tegra/tegra20_ac97.h
Stephen Warren - Jan. 8, 2013, 10:10 p.m.
On 01/04/2013 06:18 PM, Lucas Stach wrote:
> This adds the driver for the Tegra 2x AC97 host controller.
> 
> Signed-off-by: Lucas Stach <dev@lynxeye.de>

> diff --git a/Documentation/devicetree/bindings/sound/nvidia,tegra20-ac97.txt b/Documentation/devicetree/bindings/sound/nvidia,tegra20-ac97.txt

> +- nvidia,codec-sync-gpio : The Tegra GPIO controller's phandle and the number
> +  of the GPIO corresponding with the AC97 DAP _FS line
> +Example:

If you have to repost for any reason, you probably want a blank line
before the "Example:" line.

> diff --git a/sound/soc/tegra/tegra20_ac97.c b/sound/soc/tegra/tegra20_ac97.c

> +static void tegra20_ac97_codec_warm_reset(struct snd_ac97 *ac97)
> +{
> +	u32 readback;
> +	unsigned long timeout;
> +
> +	/*
> +	 * although sync line is driven by the DAC pad group warm reset using
> +	 * the controller cmd is not working, have to toggle sync line
> +	 * manually.
> +	 */
> +	gpio_request(workdata->sync_gpio, "codec-sync");
> +
> +	gpio_direction_output(workdata->sync_gpio, 1);

Would it make sense to just request the GPIO during probe()? Or, is the
sync signal used as part of the AC'97 protocol at other times?

> +static inline void tegra20_ac97_start_playback(struct tegra20_ac97 *ac97)
> +{
> +	regmap_update_bits(ac97->regmap, TEGRA20_AC97_FIFO1_SCR,
> +			   TEGRA20_AC97_FIFO_SCR_PB_QRT_MT_EN,
> +			   TEGRA20_AC97_FIFO_SCR_PB_QRT_MT_EN);
> +
> +	regmap_update_bits(ac97->regmap, TEGRA20_AC97_CTRL,
> +			   TEGRA20_AC97_CTRL_PCM_DAC_EN |
> +			   TEGRA20_AC97_CTRL_STM_EN,
> +			   TEGRA20_AC97_CTRL_PCM_DAC_EN |
> +			   TEGRA20_AC97_CTRL_STM_EN);
> +}

That sets both PCM_DAC_EN and STM_EN, but ...

> +static inline void tegra20_ac97_stop_playback(struct tegra20_ac97 *ac97)
> +{
> +	regmap_update_bits(ac97->regmap, TEGRA20_AC97_FIFO1_SCR,
> +			   TEGRA20_AC97_FIFO_SCR_PB_QRT_MT_EN, 0);
> +
> +	regmap_update_bits(ac97->regmap, TEGRA20_AC97_CTRL,
> +			   TEGRA20_AC97_CTRL_PCM_DAC_EN, 0);
> +}

... that only clears DAC_EN. Should it clear STM_EN too?
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Lucas Stach - Jan. 8, 2013, 10:22 p.m.
Am Dienstag, den 08.01.2013, 15:10 -0700 schrieb Stephen Warren:
> On 01/04/2013 06:18 PM, Lucas Stach wrote:
> > This adds the driver for the Tegra 2x AC97 host controller.
> > 
> > Signed-off-by: Lucas Stach <dev@lynxeye.de>
> 
> > diff --git a/Documentation/devicetree/bindings/sound/nvidia,tegra20-ac97.txt b/Documentation/devicetree/bindings/sound/nvidia,tegra20-ac97.txt
> 
> > +- nvidia,codec-sync-gpio : The Tegra GPIO controller's phandle and the number
> > +  of the GPIO corresponding with the AC97 DAP _FS line
> > +Example:
> 
> If you have to repost for any reason, you probably want a blank line
> before the "Example:" line.
> 
> > diff --git a/sound/soc/tegra/tegra20_ac97.c b/sound/soc/tegra/tegra20_ac97.c
> 
> > +static void tegra20_ac97_codec_warm_reset(struct snd_ac97 *ac97)
> > +{
> > +	u32 readback;
> > +	unsigned long timeout;
> > +
> > +	/*
> > +	 * although sync line is driven by the DAC pad group warm reset using
> > +	 * the controller cmd is not working, have to toggle sync line
> > +	 * manually.
> > +	 */
> > +	gpio_request(workdata->sync_gpio, "codec-sync");
> > +
> > +	gpio_direction_output(workdata->sync_gpio, 1);
> 
> Would it make sense to just request the GPIO during probe()? Or, is the
> sync signal used as part of the AC'97 protocol at other times?

Yes, the sync line is used during normal codec operation, that's why
it's explicitly requested and freed in the warm reset function. As
discussed earlier this is ugly, but unavoidable as the Tegra 2 AC97
controller misbehaves when ordered to do the warm reset. So this is just
a software hack to take over the line as a GPIO and do what the hardware
is supposed to do in this situation.
> 
> > +static inline void tegra20_ac97_start_playback(struct tegra20_ac97 *ac97)
> > +{
> > +	regmap_update_bits(ac97->regmap, TEGRA20_AC97_FIFO1_SCR,
> > +			   TEGRA20_AC97_FIFO_SCR_PB_QRT_MT_EN,
> > +			   TEGRA20_AC97_FIFO_SCR_PB_QRT_MT_EN);
> > +
> > +	regmap_update_bits(ac97->regmap, TEGRA20_AC97_CTRL,
> > +			   TEGRA20_AC97_CTRL_PCM_DAC_EN |
> > +			   TEGRA20_AC97_CTRL_STM_EN,
> > +			   TEGRA20_AC97_CTRL_PCM_DAC_EN |
> > +			   TEGRA20_AC97_CTRL_STM_EN);
> > +}
> 
> That sets both PCM_DAC_EN and STM_EN, but ...
> 
> > +static inline void tegra20_ac97_stop_playback(struct tegra20_ac97 *ac97)
> > +{
> > +	regmap_update_bits(ac97->regmap, TEGRA20_AC97_FIFO1_SCR,
> > +			   TEGRA20_AC97_FIFO_SCR_PB_QRT_MT_EN, 0);
> > +
> > +	regmap_update_bits(ac97->regmap, TEGRA20_AC97_CTRL,
> > +			   TEGRA20_AC97_CTRL_PCM_DAC_EN, 0);
> > +}
> 
> ... that only clears DAC_EN. Should it clear STM_EN too?
> 
To be honest I have no idea what STM really is, seems to be some form of
packed format selection. If not set playback outputs only more or less
random noise. Only PCM_EN controls FIFO and DMA operations though, so
it's ok to just disable this to stop playback.

Regards,
Lucas


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Stephen Warren - Jan. 8, 2013, 10:27 p.m.
On 01/08/2013 03:22 PM, Lucas Stach wrote:
> Am Dienstag, den 08.01.2013, 15:10 -0700 schrieb Stephen Warren:
>> On 01/04/2013 06:18 PM, Lucas Stach wrote:
>>> This adds the driver for the Tegra 2x AC97 host controller.

>>> diff --git a/sound/soc/tegra/tegra20_ac97.c b/sound/soc/tegra/tegra20_ac97.c

>>> +static inline void tegra20_ac97_start_playback(struct tegra20_ac97 *ac97)
>>> +{
>>> +	regmap_update_bits(ac97->regmap, TEGRA20_AC97_FIFO1_SCR,
>>> +			   TEGRA20_AC97_FIFO_SCR_PB_QRT_MT_EN,
>>> +			   TEGRA20_AC97_FIFO_SCR_PB_QRT_MT_EN);
>>> +
>>> +	regmap_update_bits(ac97->regmap, TEGRA20_AC97_CTRL,
>>> +			   TEGRA20_AC97_CTRL_PCM_DAC_EN |
>>> +			   TEGRA20_AC97_CTRL_STM_EN,
>>> +			   TEGRA20_AC97_CTRL_PCM_DAC_EN |
>>> +			   TEGRA20_AC97_CTRL_STM_EN);
>>> +}
>>
>> That sets both PCM_DAC_EN and STM_EN, but ...
>>
>>> +static inline void tegra20_ac97_stop_playback(struct tegra20_ac97 *ac97)
>>> +{
>>> +	regmap_update_bits(ac97->regmap, TEGRA20_AC97_FIFO1_SCR,
>>> +			   TEGRA20_AC97_FIFO_SCR_PB_QRT_MT_EN, 0);
>>> +
>>> +	regmap_update_bits(ac97->regmap, TEGRA20_AC97_CTRL,
>>> +			   TEGRA20_AC97_CTRL_PCM_DAC_EN, 0);
>>> +}
>>
>> ... that only clears DAC_EN. Should it clear STM_EN too?
>>
> To be honest I have no idea what STM really is, seems to be some form of
> packed format selection. If not set playback outputs only more or less
> random noise. Only PCM_EN controls FIFO and DMA operations though, so
> it's ok to just disable this to stop playback.

I'd be tempted to just hard-code those bits on in probe() then, but it's
not a big deal, so not worth spinning the patch for that.

I guess I meant to say,
Reviewed-by: Stephen Warren <swarren@nvidia.com>

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Mark Brown - Jan. 13, 2013, 11:21 p.m.
On Sat, Jan 05, 2013 at 02:18:43AM +0100, Lucas Stach wrote:

> This adds the driver for the Tegra 2x AC97 host controller.

Applied, thanks.

Patch

diff --git a/Documentation/devicetree/bindings/sound/nvidia,tegra20-ac97.txt b/Documentation/devicetree/bindings/sound/nvidia,tegra20-ac97.txt
new file mode 100644
index 0000000..c145497
--- /dev/null
+++ b/Documentation/devicetree/bindings/sound/nvidia,tegra20-ac97.txt
@@ -0,0 +1,22 @@ 
+NVIDIA Tegra 20 AC97 controller
+
+Required properties:
+- compatible : "nvidia,tegra20-ac97"
+- reg : Should contain AC97 controller registers location and length
+- interrupts : Should contain AC97 interrupt
+- nvidia,dma-request-selector : The Tegra DMA controller's phandle and
+  request selector for the AC97 controller
+- nvidia,codec-reset-gpio : The Tegra GPIO controller's phandle and the number
+  of the GPIO used to reset the external AC97 codec
+- nvidia,codec-sync-gpio : The Tegra GPIO controller's phandle and the number
+  of the GPIO corresponding with the AC97 DAP _FS line
+Example:
+
+ac97@70002000 {
+	compatible = "nvidia,tegra20-ac97";
+	reg = <0x70002000 0x200>;
+	interrupts = <0 81 0x04>;
+	nvidia,dma-request-selector = <&apbdma 12>;
+	nvidia,codec-reset-gpio = <&gpio 170 0>;
+	nvidia,codec-sync-gpio = <&gpio 120 0>;
+};
diff --git a/sound/soc/tegra/Kconfig b/sound/soc/tegra/Kconfig
index 19e5fe7..4b3a2b8 100644
--- a/sound/soc/tegra/Kconfig
+++ b/sound/soc/tegra/Kconfig
@@ -6,6 +6,16 @@  config SND_SOC_TEGRA
 	help
 	  Say Y or M here if you want support for SoC audio on Tegra.
 
+config SND_SOC_TEGRA20_AC97
+	tristate
+	depends on SND_SOC_TEGRA && ARCH_TEGRA_2x_SOC
+	select SND_SOC_AC97_BUS
+	select SND_SOC_TEGRA20_DAS
+	help
+	  Say Y or M if you want to add support for codecs attached to the
+	  Tegra20 AC97 interface. You will also need to select the individual
+	  machine drivers to support below.
+
 config SND_SOC_TEGRA20_DAS
 	tristate
 	depends on SND_SOC_TEGRA && ARCH_TEGRA_2x_SOC
diff --git a/sound/soc/tegra/Makefile b/sound/soc/tegra/Makefile
index 391e78a..02513d9 100644
--- a/sound/soc/tegra/Makefile
+++ b/sound/soc/tegra/Makefile
@@ -1,6 +1,7 @@ 
 # Tegra platform Support
 snd-soc-tegra-pcm-objs := tegra_pcm.o
 snd-soc-tegra-utils-objs += tegra_asoc_utils.o
+snd-soc-tegra20-ac97-objs := tegra20_ac97.o
 snd-soc-tegra20-das-objs := tegra20_das.o
 snd-soc-tegra20-i2s-objs := tegra20_i2s.o
 snd-soc-tegra20-spdif-objs := tegra20_spdif.o
@@ -9,6 +10,7 @@  snd-soc-tegra30-i2s-objs := tegra30_i2s.o
 
 obj-$(CONFIG_SND_SOC_TEGRA) += snd-soc-tegra-pcm.o
 obj-$(CONFIG_SND_SOC_TEGRA) += snd-soc-tegra-utils.o
+obj-$(CONFIG_SND_SOC_TEGRA20_AC97) += snd-soc-tegra20-ac97.o
 obj-$(CONFIG_SND_SOC_TEGRA20_DAS) += snd-soc-tegra20-das.o
 obj-$(CONFIG_SND_SOC_TEGRA20_I2S) += snd-soc-tegra20-i2s.o
 obj-$(CONFIG_SND_SOC_TEGRA20_SPDIF) += snd-soc-tegra20-spdif.o
diff --git a/sound/soc/tegra/tegra20_ac97.c b/sound/soc/tegra/tegra20_ac97.c
new file mode 100644
index 0000000..1bae73b
--- /dev/null
+++ b/sound/soc/tegra/tegra20_ac97.c
@@ -0,0 +1,480 @@ 
+/*
+ * tegra20_ac97.c - Tegra20 AC97 platform driver
+ *
+ * Copyright (c) 2012 Lucas Stach <dev@lynxeye.de>
+ *
+ * Partly based on code copyright/by:
+ *
+ * Copyright (c) 2011,2012 Toradex Inc.
+ *
+ * This program is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU General Public License
+ * version 2 as published by the Free Software Foundation.
+ *
+ * This program is distributed in the hope that it will be useful, but
+ * WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
+ * General Public License for more details.
+ *
+ */
+
+#include <linux/clk.h>
+#include <linux/delay.h>
+#include <linux/device.h>
+#include <linux/gpio.h>
+#include <linux/io.h>
+#include <linux/jiffies.h>
+#include <linux/module.h>
+#include <linux/of.h>
+#include <linux/of_gpio.h>
+#include <linux/platform_device.h>
+#include <linux/pm_runtime.h>
+#include <linux/regmap.h>
+#include <linux/slab.h>
+#include <sound/core.h>
+#include <sound/pcm.h>
+#include <sound/pcm_params.h>
+#include <sound/soc.h>
+
+#include "tegra_asoc_utils.h"
+#include "tegra20_ac97.h"
+
+#define DRV_NAME "tegra20-ac97"
+
+static struct tegra20_ac97 *workdata;
+
+static void tegra20_ac97_codec_reset(struct snd_ac97 *ac97)
+{
+	u32 readback;
+	unsigned long timeout;
+
+	/* reset line is not driven by DAC pad group, have to toggle GPIO */
+	gpio_set_value(workdata->reset_gpio, 0);
+	udelay(2);
+
+	gpio_set_value(workdata->reset_gpio, 1);
+	udelay(2);
+
+	timeout = jiffies + msecs_to_jiffies(100);
+
+	do {
+		regmap_read(workdata->regmap, TEGRA20_AC97_STATUS1, &readback);
+		if (readback & TEGRA20_AC97_STATUS1_CODEC1_RDY)
+			break;
+		usleep_range(1000, 2000);
+	} while (!time_after(jiffies, timeout));
+}
+
+static void tegra20_ac97_codec_warm_reset(struct snd_ac97 *ac97)
+{
+	u32 readback;
+	unsigned long timeout;
+
+	/*
+	 * although sync line is driven by the DAC pad group warm reset using
+	 * the controller cmd is not working, have to toggle sync line
+	 * manually.
+	 */
+	gpio_request(workdata->sync_gpio, "codec-sync");
+
+	gpio_direction_output(workdata->sync_gpio, 1);
+
+	udelay(2);
+	gpio_set_value(workdata->sync_gpio, 0);
+	udelay(2);
+	gpio_free(workdata->sync_gpio);
+
+	timeout = jiffies + msecs_to_jiffies(100);
+
+	do {
+		regmap_read(workdata->regmap, TEGRA20_AC97_STATUS1, &readback);
+		if (readback & TEGRA20_AC97_STATUS1_CODEC1_RDY)
+			break;
+		usleep_range(1000, 2000);
+	} while (!time_after(jiffies, timeout));
+}
+
+static unsigned short tegra20_ac97_codec_read(struct snd_ac97 *ac97_snd,
+					      unsigned short reg)
+{
+	u32 readback;
+	unsigned long timeout;
+
+	regmap_write(workdata->regmap, TEGRA20_AC97_CMD,
+		     (((reg | 0x80) << TEGRA20_AC97_CMD_CMD_ADDR_SHIFT) &
+		      TEGRA20_AC97_CMD_CMD_ADDR_MASK) |
+		     TEGRA20_AC97_CMD_BUSY);
+
+	timeout = jiffies + msecs_to_jiffies(100);
+
+	do {
+		regmap_read(workdata->regmap, TEGRA20_AC97_STATUS1, &readback);
+		if (readback & TEGRA20_AC97_STATUS1_STA_VALID1)
+			break;
+		usleep_range(1000, 2000);
+	} while (!time_after(jiffies, timeout));
+
+	return ((readback & TEGRA20_AC97_STATUS1_STA_DATA1_MASK) >>
+		TEGRA20_AC97_STATUS1_STA_DATA1_SHIFT);
+}
+
+static void tegra20_ac97_codec_write(struct snd_ac97 *ac97_snd,
+				     unsigned short reg, unsigned short val)
+{
+	u32 readback;
+	unsigned long timeout;
+
+	regmap_write(workdata->regmap, TEGRA20_AC97_CMD,
+		     ((reg << TEGRA20_AC97_CMD_CMD_ADDR_SHIFT) &
+		      TEGRA20_AC97_CMD_CMD_ADDR_MASK) |
+		     ((val << TEGRA20_AC97_CMD_CMD_DATA_SHIFT) &
+		      TEGRA20_AC97_CMD_CMD_DATA_MASK) |
+		     TEGRA20_AC97_CMD_BUSY);
+
+	timeout = jiffies + msecs_to_jiffies(100);
+
+	do {
+		regmap_read(workdata->regmap, TEGRA20_AC97_CMD, &readback);
+		if (!(readback & TEGRA20_AC97_CMD_BUSY))
+			break;
+		usleep_range(1000, 2000);
+	} while (!time_after(jiffies, timeout));
+}
+
+struct snd_ac97_bus_ops soc_ac97_ops = {
+	.read		= tegra20_ac97_codec_read,
+	.write		= tegra20_ac97_codec_write,
+	.reset		= tegra20_ac97_codec_reset,
+	.warm_reset	= tegra20_ac97_codec_warm_reset,
+};
+EXPORT_SYMBOL_GPL(soc_ac97_ops);
+
+static inline void tegra20_ac97_start_playback(struct tegra20_ac97 *ac97)
+{
+	regmap_update_bits(ac97->regmap, TEGRA20_AC97_FIFO1_SCR,
+			   TEGRA20_AC97_FIFO_SCR_PB_QRT_MT_EN,
+			   TEGRA20_AC97_FIFO_SCR_PB_QRT_MT_EN);
+
+	regmap_update_bits(ac97->regmap, TEGRA20_AC97_CTRL,
+			   TEGRA20_AC97_CTRL_PCM_DAC_EN |
+			   TEGRA20_AC97_CTRL_STM_EN,
+			   TEGRA20_AC97_CTRL_PCM_DAC_EN |
+			   TEGRA20_AC97_CTRL_STM_EN);
+}
+
+static inline void tegra20_ac97_stop_playback(struct tegra20_ac97 *ac97)
+{
+	regmap_update_bits(ac97->regmap, TEGRA20_AC97_FIFO1_SCR,
+			   TEGRA20_AC97_FIFO_SCR_PB_QRT_MT_EN, 0);
+
+	regmap_update_bits(ac97->regmap, TEGRA20_AC97_CTRL,
+			   TEGRA20_AC97_CTRL_PCM_DAC_EN, 0);
+}
+
+static inline void tegra20_ac97_start_capture(struct tegra20_ac97 *ac97)
+{
+	regmap_update_bits(ac97->regmap, TEGRA20_AC97_FIFO1_SCR,
+			   TEGRA20_AC97_FIFO_SCR_REC_FULL_EN,
+			   TEGRA20_AC97_FIFO_SCR_REC_FULL_EN);
+}
+
+static inline void tegra20_ac97_stop_capture(struct tegra20_ac97 *ac97)
+{
+	regmap_update_bits(ac97->regmap, TEGRA20_AC97_FIFO1_SCR,
+			   TEGRA20_AC97_FIFO_SCR_REC_FULL_EN, 0);
+}
+
+static int tegra20_ac97_trigger(struct snd_pcm_substream *substream, int cmd,
+				struct snd_soc_dai *dai)
+{
+	struct tegra20_ac97 *ac97 = snd_soc_dai_get_drvdata(dai);
+
+	switch (cmd) {
+	case SNDRV_PCM_TRIGGER_START:
+	case SNDRV_PCM_TRIGGER_PAUSE_RELEASE:
+	case SNDRV_PCM_TRIGGER_RESUME:
+		if (substream->stream == SNDRV_PCM_STREAM_PLAYBACK)
+			tegra20_ac97_start_playback(ac97);
+		else
+			tegra20_ac97_start_capture(ac97);
+		break;
+	case SNDRV_PCM_TRIGGER_STOP:
+	case SNDRV_PCM_TRIGGER_PAUSE_PUSH:
+	case SNDRV_PCM_TRIGGER_SUSPEND:
+		if (substream->stream == SNDRV_PCM_STREAM_PLAYBACK)
+			tegra20_ac97_stop_playback(ac97);
+		else
+			tegra20_ac97_stop_capture(ac97);
+		break;
+	default:
+		return -EINVAL;
+	}
+
+	return 0;
+}
+
+static const struct snd_soc_dai_ops tegra20_ac97_dai_ops = {
+	.trigger	= tegra20_ac97_trigger,
+};
+
+static int tegra20_ac97_probe(struct snd_soc_dai *dai)
+{
+	struct tegra20_ac97 *ac97 = snd_soc_dai_get_drvdata(dai);
+
+	dai->capture_dma_data = &ac97->capture_dma_data;
+	dai->playback_dma_data = &ac97->playback_dma_data;
+
+	return 0;
+}
+
+static struct snd_soc_dai_driver tegra20_ac97_dai = {
+	.name = "tegra-ac97-pcm",
+	.ac97_control = 1,
+	.probe = tegra20_ac97_probe,
+	.playback = {
+		.stream_name = "PCM Playback",
+		.channels_min = 2,
+		.channels_max = 2,
+		.rates = SNDRV_PCM_RATE_8000_48000,
+		.formats = SNDRV_PCM_FMTBIT_S16_LE,
+	},
+	.capture = {
+		.stream_name = "PCM Capture",
+		.channels_min = 2,
+		.channels_max = 2,
+		.rates = SNDRV_PCM_RATE_8000_48000,
+		.formats = SNDRV_PCM_FMTBIT_S16_LE,
+	},
+	.ops = &tegra20_ac97_dai_ops,
+};
+
+static bool tegra20_ac97_wr_rd_reg(struct device *dev, unsigned int reg)
+{
+	switch (reg) {
+	case TEGRA20_AC97_CTRL:
+	case TEGRA20_AC97_CMD:
+	case TEGRA20_AC97_STATUS1:
+	case TEGRA20_AC97_FIFO1_SCR:
+	case TEGRA20_AC97_FIFO_TX1:
+	case TEGRA20_AC97_FIFO_RX1:
+		return true;
+	default:
+		break;
+	}
+
+	return false;
+}
+
+static bool tegra20_ac97_volatile_reg(struct device *dev, unsigned int reg)
+{
+	switch (reg) {
+	case TEGRA20_AC97_STATUS1:
+	case TEGRA20_AC97_FIFO1_SCR:
+	case TEGRA20_AC97_FIFO_TX1:
+	case TEGRA20_AC97_FIFO_RX1:
+		return true;
+	default:
+		break;
+	}
+
+	return false;
+}
+
+static bool tegra20_ac97_precious_reg(struct device *dev, unsigned int reg)
+{
+	switch (reg) {
+	case TEGRA20_AC97_FIFO_TX1:
+	case TEGRA20_AC97_FIFO_RX1:
+		return true;
+	default:
+		break;
+	}
+
+	return false;
+}
+
+static const struct regmap_config tegra20_ac97_regmap_config = {
+	.reg_bits = 32,
+	.reg_stride = 4,
+	.val_bits = 32,
+	.max_register = TEGRA20_AC97_FIFO_RX1,
+	.writeable_reg = tegra20_ac97_wr_rd_reg,
+	.readable_reg = tegra20_ac97_wr_rd_reg,
+	.volatile_reg = tegra20_ac97_volatile_reg,
+	.precious_reg = tegra20_ac97_precious_reg,
+	.cache_type = REGCACHE_RBTREE,
+};
+
+static int tegra20_ac97_platform_probe(struct platform_device *pdev)
+{
+	struct tegra20_ac97 *ac97;
+	struct resource *mem, *memregion;
+	u32 of_dma[2];
+	void __iomem *regs;
+	int ret = 0;
+
+	ac97 = devm_kzalloc(&pdev->dev, sizeof(struct tegra20_ac97),
+			    GFP_KERNEL);
+	if (!ac97) {
+		dev_err(&pdev->dev, "Can't allocate tegra20_ac97\n");
+		ret = -ENOMEM;
+		goto err;
+	}
+	dev_set_drvdata(&pdev->dev, ac97);
+
+	ac97->clk_ac97 = clk_get(&pdev->dev, NULL);
+	if (IS_ERR(ac97->clk_ac97)) {
+		dev_err(&pdev->dev, "Can't retrieve ac97 clock\n");
+		ret = PTR_ERR(ac97->clk_ac97);
+		goto err;
+	}
+
+	mem = platform_get_resource(pdev, IORESOURCE_MEM, 0);
+	if (!mem) {
+		dev_err(&pdev->dev, "No memory resource\n");
+		ret = -ENODEV;
+		goto err_clk_put;
+	}
+
+	memregion = devm_request_mem_region(&pdev->dev, mem->start,
+					    resource_size(mem), DRV_NAME);
+	if (!memregion) {
+		dev_err(&pdev->dev, "Memory region already claimed\n");
+		ret = -EBUSY;
+		goto err_clk_put;
+	}
+
+	regs = devm_ioremap(&pdev->dev, mem->start, resource_size(mem));
+	if (!regs) {
+		dev_err(&pdev->dev, "ioremap failed\n");
+		ret = -ENOMEM;
+		goto err_clk_put;
+	}
+
+	ac97->regmap = devm_regmap_init_mmio(&pdev->dev, regs,
+					    &tegra20_ac97_regmap_config);
+	if (IS_ERR(ac97->regmap)) {
+		dev_err(&pdev->dev, "regmap init failed\n");
+		ret = PTR_ERR(ac97->regmap);
+		goto err_clk_put;
+	}
+
+	if (of_property_read_u32_array(pdev->dev.of_node,
+				       "nvidia,dma-request-selector",
+				       of_dma, 2) < 0) {
+		dev_err(&pdev->dev, "No DMA resource\n");
+		ret = -ENODEV;
+		goto err_clk_put;
+	}
+
+	ac97->reset_gpio = of_get_named_gpio(pdev->dev.of_node,
+					     "nvidia,codec-reset-gpio", 0);
+	if (gpio_is_valid(ac97->reset_gpio)) {
+		ret = devm_gpio_request_one(&pdev->dev, ac97->reset_gpio,
+					    GPIOF_OUT_INIT_HIGH, "codec-reset");
+		if (ret) {
+			dev_err(&pdev->dev, "could not get codec-reset GPIO\n");
+			goto err_clk_put;
+		}
+	} else {
+		dev_err(&pdev->dev, "no codec-reset GPIO supplied\n");
+		goto err_clk_put;
+	}
+
+	ac97->sync_gpio = of_get_named_gpio(pdev->dev.of_node,
+					    "nvidia,codec-sync-gpio", 0);
+	if (!gpio_is_valid(ac97->sync_gpio)) {
+		dev_err(&pdev->dev, "no codec-sync GPIO supplied\n");
+		goto err_clk_put;
+	}
+
+	ac97->capture_dma_data.addr = mem->start + TEGRA20_AC97_FIFO_RX1;
+	ac97->capture_dma_data.wrap = 4;
+	ac97->capture_dma_data.width = 32;
+	ac97->capture_dma_data.req_sel = of_dma[1];
+
+	ac97->playback_dma_data.addr = mem->start + TEGRA20_AC97_FIFO_TX1;
+	ac97->playback_dma_data.wrap = 4;
+	ac97->playback_dma_data.width = 32;
+	ac97->playback_dma_data.req_sel = of_dma[1];
+
+	ret = snd_soc_register_dais(&pdev->dev, &tegra20_ac97_dai, 1);
+	if (ret) {
+		dev_err(&pdev->dev, "Could not register DAI: %d\n", ret);
+		ret = -ENOMEM;
+		goto err_clk_put;
+	}
+
+	ret = tegra_pcm_platform_register(&pdev->dev);
+	if (ret) {
+		dev_err(&pdev->dev, "Could not register PCM: %d\n", ret);
+		goto err_unregister_dai;
+	}
+
+	ret = tegra_asoc_utils_init(&ac97->util_data, &pdev->dev);
+	if (ret)
+		goto err_unregister_pcm;
+
+	ret = tegra_asoc_utils_set_ac97_rate(&ac97->util_data);
+	if (ret)
+		goto err_asoc_utils_fini;
+
+	ret = clk_prepare_enable(ac97->clk_ac97);
+	if (ret) {
+		dev_err(&pdev->dev, "clk_enable failed: %d\n", ret);
+		goto err_asoc_utils_fini;
+	}
+
+	/* XXX: crufty ASoC AC97 API - only one AC97 codec allowed */
+	workdata = ac97;
+
+	return 0;
+
+err_asoc_utils_fini:
+	tegra_asoc_utils_fini(&ac97->util_data);
+err_unregister_pcm:
+	tegra_pcm_platform_unregister(&pdev->dev);
+err_unregister_dai:
+	snd_soc_unregister_dai(&pdev->dev);
+err_clk_put:
+	clk_put(ac97->clk_ac97);
+err:
+	return ret;
+}
+
+static int tegra20_ac97_platform_remove(struct platform_device *pdev)
+{
+	struct tegra20_ac97 *ac97 = dev_get_drvdata(&pdev->dev);
+
+	tegra_pcm_platform_unregister(&pdev->dev);
+	snd_soc_unregister_dai(&pdev->dev);
+
+	tegra_asoc_utils_fini(&ac97->util_data);
+
+	clk_disable_unprepare(ac97->clk_ac97);
+	clk_put(ac97->clk_ac97);
+
+	return 0;
+}
+
+static const struct of_device_id tegra20_ac97_of_match[] __devinitconst = {
+	{ .compatible = "nvidia,tegra20-ac97", },
+	{},
+};
+
+static struct platform_driver tegra20_ac97_driver = {
+	.driver = {
+		.name = DRV_NAME,
+		.owner = THIS_MODULE,
+		.of_match_table = tegra20_ac97_of_match,
+	},
+	.probe = tegra20_ac97_platform_probe,
+	.remove = tegra20_ac97_platform_remove,
+};
+module_platform_driver(tegra20_ac97_driver);
+
+MODULE_AUTHOR("Lucas Stach");
+MODULE_DESCRIPTION("Tegra20 AC97 ASoC driver");
+MODULE_LICENSE("GPL v2");
+MODULE_ALIAS("platform:" DRV_NAME);
+MODULE_DEVICE_TABLE(of, tegra20_ac97_of_match);
diff --git a/sound/soc/tegra/tegra20_ac97.h b/sound/soc/tegra/tegra20_ac97.h
new file mode 100644
index 0000000..dddc682
--- /dev/null
+++ b/sound/soc/tegra/tegra20_ac97.h
@@ -0,0 +1,95 @@ 
+/*
+ * tegra20_ac97.h - Definitions for the Tegra20 AC97 controller driver
+ *
+ * Copyright (c) 2012 Lucas Stach <dev@lynxeye.de>
+ *
+ * Partly based on code copyright/by:
+ *
+ * Copyright (c) 2011,2012 Toradex Inc.
+ *
+ * This program is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU General Public License
+ * version 2 as published by the Free Software Foundation.
+ *
+ * This program is distributed in the hope that it will be useful, but
+ * WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
+ * General Public License for more details.
+ *
+ */
+
+#ifndef __TEGRA20_AC97_H__
+#define __TEGRA20_AC97_H__
+
+#include "tegra_pcm.h"
+
+#define TEGRA20_AC97_CTRL				0x00
+#define TEGRA20_AC97_CMD				0x04
+#define TEGRA20_AC97_STATUS1				0x08
+/* ... */
+#define TEGRA20_AC97_FIFO1_SCR				0x1c
+/* ... */
+#define TEGRA20_AC97_FIFO_TX1				0x40
+#define TEGRA20_AC97_FIFO_RX1				0x80
+
+/* TEGRA20_AC97_CTRL */
+#define TEGRA20_AC97_CTRL_STM2_EN			(1 << 16)
+#define TEGRA20_AC97_CTRL_DOUBLE_SAMPLING_EN		(1 << 11)
+#define TEGRA20_AC97_CTRL_IO_CNTRL_EN			(1 << 10)
+#define TEGRA20_AC97_CTRL_HSET_DAC_EN			(1 << 9)
+#define TEGRA20_AC97_CTRL_LINE2_DAC_EN			(1 << 8)
+#define TEGRA20_AC97_CTRL_PCM_LFE_EN			(1 << 7)
+#define TEGRA20_AC97_CTRL_PCM_SUR_EN			(1 << 6)
+#define TEGRA20_AC97_CTRL_PCM_CEN_DAC_EN		(1 << 5)
+#define TEGRA20_AC97_CTRL_LINE1_DAC_EN			(1 << 4)
+#define TEGRA20_AC97_CTRL_PCM_DAC_EN			(1 << 3)
+#define TEGRA20_AC97_CTRL_COLD_RESET			(1 << 2)
+#define TEGRA20_AC97_CTRL_WARM_RESET			(1 << 1)
+#define TEGRA20_AC97_CTRL_STM_EN			(1 << 0)
+
+/* TEGRA20_AC97_CMD */
+#define TEGRA20_AC97_CMD_CMD_ADDR_SHIFT			24
+#define TEGRA20_AC97_CMD_CMD_ADDR_MASK			(0xff << TEGRA20_AC97_CMD_CMD_ADDR_SHIFT)
+#define TEGRA20_AC97_CMD_CMD_DATA_SHIFT			8
+#define TEGRA20_AC97_CMD_CMD_DATA_MASK			(0xffff << TEGRA20_AC97_CMD_CMD_DATA_SHIFT)
+#define TEGRA20_AC97_CMD_CMD_ID_SHIFT			2
+#define TEGRA20_AC97_CMD_CMD_ID_MASK			(0x3 << TEGRA20_AC97_CMD_CMD_ID_SHIFT)
+#define TEGRA20_AC97_CMD_BUSY				(1 << 0)
+
+/* TEGRA20_AC97_STATUS1 */
+#define TEGRA20_AC97_STATUS1_STA_ADDR1_SHIFT		24
+#define TEGRA20_AC97_STATUS1_STA_ADDR1_MASK		(0xff << TEGRA20_AC97_STATUS1_STA_ADDR1_SHIFT)
+#define TEGRA20_AC97_STATUS1_STA_DATA1_SHIFT		8
+#define TEGRA20_AC97_STATUS1_STA_DATA1_MASK		(0xffff << TEGRA20_AC97_STATUS1_STA_DATA1_SHIFT)
+#define TEGRA20_AC97_STATUS1_STA_VALID1			(1 << 2)
+#define TEGRA20_AC97_STATUS1_STANDBY1			(1 << 1)
+#define TEGRA20_AC97_STATUS1_CODEC1_RDY			(1 << 0)
+
+/* TEGRA20_AC97_FIFO1_SCR */
+#define TEGRA20_AC97_FIFO_SCR_REC_MT_CNT_SHIFT		27
+#define TEGRA20_AC97_FIFO_SCR_REC_MT_CNT_MASK		(0x1f << TEGRA20_AC97_FIFO_SCR_REC_MT_CNT_SHIFT)
+#define TEGRA20_AC97_FIFO_SCR_PB_MT_CNT_SHIFT		22
+#define TEGRA20_AC97_FIFO_SCR_PB_MT_CNT_MASK		(0x1f << TEGRA20_AC97_FIFO_SCR_PB_MT_CNT_SHIFT)
+#define TEGRA20_AC97_FIFO_SCR_REC_OVERRUN_INT_STA	(1 << 19)
+#define TEGRA20_AC97_FIFO_SCR_PB_UNDERRUN_INT_STA	(1 << 18)
+#define TEGRA20_AC97_FIFO_SCR_REC_FORCE_MT		(1 << 17)
+#define TEGRA20_AC97_FIFO_SCR_PB_FORCE_MT		(1 << 16)
+#define TEGRA20_AC97_FIFO_SCR_REC_FULL_EN		(1 << 15)
+#define TEGRA20_AC97_FIFO_SCR_REC_3QRT_FULL_EN		(1 << 14)
+#define TEGRA20_AC97_FIFO_SCR_REC_QRT_FULL_EN		(1 << 13)
+#define TEGRA20_AC97_FIFO_SCR_REC_EMPTY_EN		(1 << 12)
+#define TEGRA20_AC97_FIFO_SCR_PB_NOT_FULL_EN		(1 << 11)
+#define TEGRA20_AC97_FIFO_SCR_PB_QRT_MT_EN		(1 << 10)
+#define TEGRA20_AC97_FIFO_SCR_PB_3QRT_MT_EN		(1 << 9)
+#define TEGRA20_AC97_FIFO_SCR_PB_EMPTY_MT_EN		(1 << 8)
+
+struct tegra20_ac97 {
+	struct clk *clk_ac97;
+	struct tegra_pcm_dma_params capture_dma_data;
+	struct tegra_pcm_dma_params playback_dma_data;
+	struct regmap *regmap;
+	int reset_gpio;
+	int sync_gpio;
+	struct tegra_asoc_utils_data util_data;
+};
+#endif /* __TEGRA20_AC97_H__ */