ALSA: Add ALSA driver for Atmel AC97 controller

This patch adds ALSA support for the AC97 controller found on Atmel
AVR32 devices.

Tested on ATSTK1006 + ATSTK1000 with a development board with a AC97
codec.

Signed-off-by: Hans-Christian Egtvedt <hans-christian.egtvedt@atmel.com>
Signed-off-by: Takashi Iwai <tiwai@suse.de>

1 files changed, 932 insertions, 0 deletions

diff --git a/sound/atmel/ac97c.c b/sound/atmel/ac97c.c
new file mode 100644
index 0000000..dd72e00
--- /dev/null
+++ b/sound/atmel/ac97c.c
@@ -0,0 +1,932 @@
+/*
+ * Driver for the Atmel AC97C controller
+ *
+ * Copyright (C) 2005-2009 Atmel Corporation
+ *
+ * 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.
+ */
+#include <linux/clk.h>
+#include <linux/delay.h>
+#include <linux/bitmap.h>
+#include <linux/dmaengine.h>
+#include <linux/dma-mapping.h>
+#include <linux/init.h>
+#include <linux/interrupt.h>
+#include <linux/module.h>
+#include <linux/platform_device.h>
+#include <linux/mutex.h>
+#include <linux/gpio.h>
+#include <linux/io.h>
+
+#include <sound/core.h>
+#include <sound/initval.h>
+#include <sound/pcm.h>
+#include <sound/pcm_params.h>
+#include <sound/ac97_codec.h>
+#include <sound/atmel-ac97c.h>
+#include <sound/memalloc.h>
+
+#include <linux/dw_dmac.h>
+
+#include "ac97c.h"
+
+enum {
+	DMA_TX_READY = 0,
+	DMA_RX_READY,
+	DMA_TX_CHAN_PRESENT,
+	DMA_RX_CHAN_PRESENT,
+};
+
+/* Serialize access to opened variable */
+static DEFINE_MUTEX(opened_mutex);
+
+struct atmel_ac97c_dma {
+	struct dma_chan			*rx_chan;
+	struct dma_chan			*tx_chan;
+};
+
+struct atmel_ac97c {
+	struct clk			*pclk;
+	struct platform_device		*pdev;
+	struct atmel_ac97c_dma		dma;
+
+	struct snd_pcm_substream	*playback_substream;
+	struct snd_pcm_substream	*capture_substream;
+	struct snd_card			*card;
+	struct snd_pcm			*pcm;
+	struct snd_ac97			*ac97;
+	struct snd_ac97_bus		*ac97_bus;
+
+	u64				cur_format;
+	unsigned int			cur_rate;
+	unsigned long			flags;
+	/* Serialize access to opened variable */
+	spinlock_t			lock;
+	void __iomem			*regs;
+	int				opened;
+	int				reset_pin;
+};
+
+#define get_chip(card) ((struct atmel_ac97c *)(card)->private_data)
+
+#define ac97c_writel(chip, reg, val)			\
+	__raw_writel((val), (chip)->regs + AC97C_##reg)
+#define ac97c_readl(chip, reg)				\
+	__raw_readl((chip)->regs + AC97C_##reg)
+
+/* This function is called by the DMA driver. */
+static void atmel_ac97c_dma_playback_period_done(void *arg)
+{
+	struct atmel_ac97c *chip = arg;
+	snd_pcm_period_elapsed(chip->playback_substream);
+}
+
+static void atmel_ac97c_dma_capture_period_done(void *arg)
+{
+	struct atmel_ac97c *chip = arg;
+	snd_pcm_period_elapsed(chip->capture_substream);
+}
+
+static int atmel_ac97c_prepare_dma(struct atmel_ac97c *chip,
+		struct snd_pcm_substream *substream,
+		enum dma_data_direction direction)
+{
+	struct dma_chan			*chan;
+	struct dw_cyclic_desc		*cdesc;
+	struct snd_pcm_runtime		*runtime = substream->runtime;
+	unsigned long			buffer_len, period_len;
+
+	/*
+	 * We don't do DMA on "complex" transfers, i.e. with
+	 * non-halfword-aligned buffers or lengths.
+	 */
+	if (runtime->dma_addr & 1 || runtime->buffer_size & 1) {
+		dev_dbg(&chip->pdev->dev, "too complex transfer\n");
+		return -EINVAL;
+	}
+
+	if (direction == DMA_TO_DEVICE)
+		chan = chip->dma.tx_chan;
+	else
+		chan = chip->dma.rx_chan;
+
+	buffer_len = frames_to_bytes(runtime, runtime->buffer_size);
+	period_len = frames_to_bytes(runtime, runtime->period_size);
+
+	cdesc = dw_dma_cyclic_prep(chan, runtime->dma_addr, buffer_len,
+			period_len, direction);
+	if (IS_ERR(cdesc)) {
+		dev_dbg(&chip->pdev->dev, "could not prepare cyclic DMA\n");
+		return PTR_ERR(cdesc);
+	}
+
+	if (direction == DMA_TO_DEVICE) {
+		cdesc->period_callback = atmel_ac97c_dma_playback_period_done;
+		set_bit(DMA_TX_READY, &chip->flags);
+	} else {
+		cdesc->period_callback = atmel_ac97c_dma_capture_period_done;
+		set_bit(DMA_RX_READY, &chip->flags);
+	}
+
+	cdesc->period_callback_param = chip;
+
+	return 0;
+}
+
+static struct snd_pcm_hardware atmel_ac97c_hw = {
+	.info			= (SNDRV_PCM_INFO_MMAP
+				  | SNDRV_PCM_INFO_MMAP_VALID
+				  | SNDRV_PCM_INFO_INTERLEAVED
+				  | SNDRV_PCM_INFO_BLOCK_TRANSFER
+				  | SNDRV_PCM_INFO_JOINT_DUPLEX
+				  | SNDRV_PCM_INFO_RESUME
+				  | SNDRV_PCM_INFO_PAUSE),
+	.formats		= (SNDRV_PCM_FMTBIT_S16_BE
+				  | SNDRV_PCM_FMTBIT_S16_LE),
+	.rates			= (SNDRV_PCM_RATE_CONTINUOUS),
+	.rate_min		= 4000,
+	.rate_max		= 48000,
+	.channels_min		= 1,
+	.channels_max		= 2,
+	.buffer_bytes_max	= 64 * 4096,
+	.period_bytes_min	= 4096,
+	.period_bytes_max	= 4096,
+	.periods_min		= 4,
+	.periods_max		= 64,
+};
+
+static int atmel_ac97c_playback_open(struct snd_pcm_substream *substream)
+{
+	struct atmel_ac97c *chip = snd_pcm_substream_chip(substream);
+	struct snd_pcm_runtime *runtime = substream->runtime;
+
+	mutex_lock(&opened_mutex);
+	chip->opened++;
+	runtime->hw = atmel_ac97c_hw;
+	if (chip->cur_rate) {
+		runtime->hw.rate_min = chip->cur_rate;
+		runtime->hw.rate_max = chip->cur_rate;
+	}
+	if (chip->cur_format)
+		runtime->hw.formats = (1ULL << chip->cur_format);
+	mutex_unlock(&opened_mutex);
+	chip->playback_substream = substream;
+	return 0;
+}
+
+static int atmel_ac97c_capture_open(struct snd_pcm_substream *substream)
+{
+	struct atmel_ac97c *chip = snd_pcm_substream_chip(substream);
+	struct snd_pcm_runtime *runtime = substream->runtime;
+
+	mutex_lock(&opened_mutex);
+	chip->opened++;
+	runtime->hw = atmel_ac97c_hw;
+	if (chip->cur_rate) {
+		runtime->hw.rate_min = chip->cur_rate;
+		runtime->hw.rate_max = chip->cur_rate;
+	}
+	if (chip->cur_format)
+		runtime->hw.formats = (1ULL << chip->cur_format);
+	mutex_unlock(&opened_mutex);
+	chip->capture_substream = substream;
+	return 0;
+}
+
+static int atmel_ac97c_playback_close(struct snd_pcm_substream *substream)
+{
+	struct atmel_ac97c *chip = snd_pcm_substream_chip(substream);
+
+	mutex_lock(&opened_mutex);
+	chip->opened--;
+	if (!chip->opened) {
+		chip->cur_rate = 0;
+		chip->cur_format = 0;
+	}
+	mutex_unlock(&opened_mutex);
+
+	chip->playback_substream = NULL;
+
+	return 0;
+}
+
+static int atmel_ac97c_capture_close(struct snd_pcm_substream *substream)
+{
+	struct atmel_ac97c *chip = snd_pcm_substream_chip(substream);
+
+	mutex_lock(&opened_mutex);
+	chip->opened--;
+	if (!chip->opened) {
+		chip->cur_rate = 0;
+		chip->cur_format = 0;
+	}
+	mutex_unlock(&opened_mutex);
+
+	chip->capture_substream = NULL;
+
+	return 0;
+}
+
+static int atmel_ac97c_playback_hw_params(struct snd_pcm_substream *substream,
+		struct snd_pcm_hw_params *hw_params)
+{
+	struct atmel_ac97c *chip = snd_pcm_substream_chip(substream);
+	int retval;
+
+	retval = snd_pcm_lib_malloc_pages(substream,
+					params_buffer_bytes(hw_params));
+	if (retval < 0)
+		return retval;
+	/* snd_pcm_lib_malloc_pages returns 1 if buffer is changed. */
+	if (retval == 1)
+		if (test_and_clear_bit(DMA_TX_READY, &chip->flags))
+			dw_dma_cyclic_free(chip->dma.tx_chan);
+
+	/* Set restrictions to params. */
+	mutex_lock(&opened_mutex);
+	chip->cur_rate = params_rate(hw_params);
+	chip->cur_format = params_format(hw_params);
+	mutex_unlock(&opened_mutex);
+
+	return retval;
+}
+
+static int atmel_ac97c_capture_hw_params(struct snd_pcm_substream *substream,
+		struct snd_pcm_hw_params *hw_params)
+{
+	struct atmel_ac97c *chip = snd_pcm_substream_chip(substream);
+	int retval;
+
+	retval = snd_pcm_lib_malloc_pages(substream,
+					params_buffer_bytes(hw_params));
+	if (retval < 0)
+		return retval;
+	/* snd_pcm_lib_malloc_pages returns 1 if buffer is changed. */
+	if (retval == 1)
+		if (test_and_clear_bit(DMA_RX_READY, &chip->flags))
+			dw_dma_cyclic_free(chip->dma.rx_chan);
+
+	/* Set restrictions to params. */
+	mutex_lock(&opened_mutex);
+	chip->cur_rate = params_rate(hw_params);
+	chip->cur_format = params_format(hw_params);
+	mutex_unlock(&opened_mutex);
+
+	return retval;
+}
+
+static int atmel_ac97c_playback_hw_free(struct snd_pcm_substream *substream)
+{
+	struct atmel_ac97c *chip = snd_pcm_substream_chip(substream);
+	if (test_and_clear_bit(DMA_TX_READY, &chip->flags))
+		dw_dma_cyclic_free(chip->dma.tx_chan);
+	return snd_pcm_lib_free_pages(substream);
+}
+
+static int atmel_ac97c_capture_hw_free(struct snd_pcm_substream *substream)
+{
+	struct atmel_ac97c *chip = snd_pcm_substream_chip(substream);
+	if (test_and_clear_bit(DMA_RX_READY, &chip->flags))
+		dw_dma_cyclic_free(chip->dma.rx_chan);
+	return snd_pcm_lib_free_pages(substream);
+}
+
+static int atmel_ac97c_playback_prepare(struct snd_pcm_substream *substream)
+{
+	struct atmel_ac97c *chip = snd_pcm_substream_chip(substream);
+	struct snd_pcm_runtime *runtime = substream->runtime;
+	unsigned long word = 0;
+	int retval;
+
+	/* assign channels to AC97C channel A */
+	switch (runtime->channels) {
+	case 1:
+		word |= AC97C_CH_ASSIGN(PCM_LEFT, A);
+		break;
+	case 2:
+		word |= AC97C_CH_ASSIGN(PCM_LEFT, A)
+			| AC97C_CH_ASSIGN(PCM_RIGHT, A);
+		break;
+	default:
+		/* TODO: support more than two channels */
+		return -EINVAL;
+		break;
+	}
+	ac97c_writel(chip, OCA, word);
+
+	/* configure sample format and size */
+	word = AC97C_CMR_DMAEN | AC97C_CMR_SIZE_16;
+
+	switch (runtime->format) {
+	case SNDRV_PCM_FORMAT_S16_LE:
+		word |= AC97C_CMR_CEM_LITTLE;
+		break;
+	case SNDRV_PCM_FORMAT_S16_BE: /* fall through */
+	default:
+		word &= ~(AC97C_CMR_CEM_LITTLE);
+		break;
+	}
+
+	ac97c_writel(chip, CAMR, word);
+
+	/* set variable rate if needed */
+	if (runtime->rate != 48000) {
+		word = ac97c_readl(chip, MR);
+		word |= AC97C_MR_VRA;
+		ac97c_writel(chip, MR, word);
+	} else {
+		word = ac97c_readl(chip, MR);
+		word &= ~(AC97C_MR_VRA);
+		ac97c_writel(chip, MR, word);
+	}
+
+	retval = snd_ac97_set_rate(chip->ac97, AC97_PCM_FRONT_DAC_RATE,
+			runtime->rate);
+	if (retval)
+		dev_dbg(&chip->pdev->dev, "could not set rate %d Hz\n",
+				runtime->rate);
+
+	if (!test_bit(DMA_TX_READY, &chip->flags))
+		retval = atmel_ac97c_prepare_dma(chip, substream,
+				DMA_TO_DEVICE);
+
+	return retval;
+}
+
+static int atmel_ac97c_capture_prepare(struct snd_pcm_substream *substream)
+{
+	struct atmel_ac97c *chip = snd_pcm_substream_chip(substream);
+	struct snd_pcm_runtime *runtime = substream->runtime;
+	unsigned long word = 0;
+	int retval;
+
+	/* assign channels to AC97C channel A */
+	switch (runtime->channels) {
+	case 1:
+		word |= AC97C_CH_ASSIGN(PCM_LEFT, A);
+		break;
+	case 2:
+		word |= AC97C_CH_ASSIGN(PCM_LEFT, A)
+			| AC97C_CH_ASSIGN(PCM_RIGHT, A);
+		break;
+	default:
+		/* TODO: support more than two channels */
+		return -EINVAL;
+		break;
+	}
+	ac97c_writel(chip, ICA, word);
+
+	/* configure sample format and size */
+	word = AC97C_CMR_DMAEN | AC97C_CMR_SIZE_16;
+
+	switch (runtime->format) {
+	case SNDRV_PCM_FORMAT_S16_LE:
+		word |= AC97C_CMR_CEM_LITTLE;
+		break;
+	case SNDRV_PCM_FORMAT_S16_BE: /* fall through */
+	default:
+		word &= ~(AC97C_CMR_CEM_LITTLE);
+		break;
+	}
+
+	ac97c_writel(chip, CAMR, word);
+
+	/* set variable rate if needed */
+	if (runtime->rate != 48000) {
+		word = ac97c_readl(chip, MR);
+		word |= AC97C_MR_VRA;
+		ac97c_writel(chip, MR, word);
+	} else {
+		word = ac97c_readl(chip, MR);
+		word &= ~(AC97C_MR_VRA);
+		ac97c_writel(chip, MR, word);
+	}
+
+	retval = snd_ac97_set_rate(chip->ac97, AC97_PCM_LR_ADC_RATE,
+			runtime->rate);
+	if (retval)
+		dev_dbg(&chip->pdev->dev, "could not set rate %d Hz\n",
+				runtime->rate);
+
+	if (!test_bit(DMA_RX_READY, &chip->flags))
+		retval = atmel_ac97c_prepare_dma(chip, substream,
+				DMA_FROM_DEVICE);
+
+	return retval;
+}
+
+static int
+atmel_ac97c_playback_trigger(struct snd_pcm_substream *substream, int cmd)
+{
+	struct atmel_ac97c *chip = snd_pcm_substream_chip(substream);
+	unsigned long camr;
+	int retval = 0;
+
+	camr = ac97c_readl(chip, CAMR);
+
+	switch (cmd) {
+	case SNDRV_PCM_TRIGGER_PAUSE_RELEASE: /* fall through */
+	case SNDRV_PCM_TRIGGER_RESUME: /* fall through */
+	case SNDRV_PCM_TRIGGER_START:
+		retval = dw_dma_cyclic_start(chip->dma.tx_chan);
+		if (retval)
+			goto out;
+		camr |= AC97C_CMR_CENA;
+		break;
+	case SNDRV_PCM_TRIGGER_PAUSE_PUSH: /* fall through */
+	case SNDRV_PCM_TRIGGER_SUSPEND: /* fall through */
+	case SNDRV_PCM_TRIGGER_STOP:
+		dw_dma_cyclic_stop(chip->dma.tx_chan);
+		if (chip->opened <= 1)
+			camr &= ~AC97C_CMR_CENA;
+		break;
+	default:
+		retval = -EINVAL;
+		goto out;
+	}
+
+	ac97c_writel(chip, CAMR, camr);
+out:
+	return retval;
+}
+
+static int
+atmel_ac97c_capture_trigger(struct snd_pcm_substream *substream, int cmd)
+{
+	struct atmel_ac97c *chip = snd_pcm_substream_chip(substream);
+	unsigned long camr;
+	int retval = 0;
+
+	camr = ac97c_readl(chip, CAMR);
+
+	switch (cmd) {
+	case SNDRV_PCM_TRIGGER_PAUSE_RELEASE: /* fall through */
+	case SNDRV_PCM_TRIGGER_RESUME: /* fall through */
+	case SNDRV_PCM_TRIGGER_START:
+		retval = dw_dma_cyclic_start(chip->dma.rx_chan);
+		if (retval)
+			goto out;
+		camr |= AC97C_CMR_CENA;
+		break;
+	case SNDRV_PCM_TRIGGER_PAUSE_PUSH: /* fall through */
+	case SNDRV_PCM_TRIGGER_SUSPEND: /* fall through */
+	case SNDRV_PCM_TRIGGER_STOP:
+		dw_dma_cyclic_stop(chip->dma.rx_chan);
+		if (chip->opened <= 1)
+			camr &= ~AC97C_CMR_CENA;
+		break;
+	default:
+		retval = -EINVAL;
+		break;
+	}
+
+	ac97c_writel(chip, CAMR, camr);
+out:
+	return retval;
+}
+
+static snd_pcm_uframes_t
+atmel_ac97c_playback_pointer(struct snd_pcm_substream *substream)
+{
+	struct atmel_ac97c	*chip = snd_pcm_substream_chip(substream);
+	struct snd_pcm_runtime	*runtime = substream->runtime;
+	snd_pcm_uframes_t	frames;
+	unsigned long		bytes;
+
+	bytes = dw_dma_get_src_addr(chip->dma.tx_chan);
+	bytes -= runtime->dma_addr;
+
+	frames = bytes_to_frames(runtime, bytes);
+	if (frames >= runtime->buffer_size)
+		frames -= runtime->buffer_size;
+	return frames;
+}
+
+static snd_pcm_uframes_t
+atmel_ac97c_capture_pointer(struct snd_pcm_substream *substream)
+{
+	struct atmel_ac97c	*chip = snd_pcm_substream_chip(substream);
+	struct snd_pcm_runtime	*runtime = substream->runtime;
+	snd_pcm_uframes_t	frames;
+	unsigned long		bytes;
+
+	bytes = dw_dma_get_dst_addr(chip->dma.rx_chan);
+	bytes -= runtime->dma_addr;
+
+	frames = bytes_to_frames(runtime, bytes);
+	if (frames >= runtime->buffer_size)
+		frames -= runtime->buffer_size;
+	return frames;
+}
+
+static struct snd_pcm_ops atmel_ac97_playback_ops = {
+	.open		= atmel_ac97c_playback_open,
+	.close		= atmel_ac97c_playback_close,
+	.ioctl		= snd_pcm_lib_ioctl,
+	.hw_params	= atmel_ac97c_playback_hw_params,
+	.hw_free	= atmel_ac97c_playback_hw_free,
+	.prepare	= atmel_ac97c_playback_prepare,
+	.trigger	= atmel_ac97c_playback_trigger,
+	.pointer	= atmel_ac97c_playback_pointer,
+};
+
+static struct snd_pcm_ops atmel_ac97_capture_ops = {
+	.open		= atmel_ac97c_capture_open,
+	.close		= atmel_ac97c_capture_close,
+	.ioctl		= snd_pcm_lib_ioctl,
+	.hw_params	= atmel_ac97c_capture_hw_params,
+	.hw_free	= atmel_ac97c_capture_hw_free,
+	.prepare	= atmel_ac97c_capture_prepare,
+	.trigger	= atmel_ac97c_capture_trigger,
+	.pointer	= atmel_ac97c_capture_pointer,
+};
+
+static int __devinit atmel_ac97c_pcm_new(struct atmel_ac97c *chip)
+{
+	struct snd_pcm		*pcm;
+	struct snd_pcm_hardware	hw = atmel_ac97c_hw;
+	int			capture, playback, retval;
+
+	capture = test_bit(DMA_RX_CHAN_PRESENT, &chip->flags);
+	playback = test_bit(DMA_TX_CHAN_PRESENT, &chip->flags);
+
+	retval = snd_pcm_new(chip->card, chip->card->shortname,
+			chip->pdev->id, playback, capture, &pcm);
+	if (retval)
+		return retval;
+
+	if (capture)
+		snd_pcm_set_ops(pcm, SNDRV_PCM_STREAM_CAPTURE,
+				&atmel_ac97_capture_ops);
+	if (playback)
+		snd_pcm_set_ops(pcm, SNDRV_PCM_STREAM_PLAYBACK,
+				&atmel_ac97_playback_ops);
+
+	retval = snd_pcm_lib_preallocate_pages_for_all(pcm, SNDRV_DMA_TYPE_DEV,
+			&chip->pdev->dev, hw.periods_min * hw.period_bytes_min,
+			hw.buffer_bytes_max);
+	if (retval)
+		return retval;
+
+	pcm->private_data = chip;
+	pcm->info_flags = 0;
+	strcpy(pcm->name, chip->card->shortname);
+	chip->pcm = pcm;
+
+	return 0;
+}
+
+static int atmel_ac97c_mixer_new(struct atmel_ac97c *chip)
+{
+	struct snd_ac97_template template;
+	memset(&template, 0, sizeof(template));
+	template.private_data = chip;
+	return snd_ac97_mixer(chip->ac97_bus, &template, &chip->ac97);
+}
+
+static void atmel_ac97c_write(struct snd_ac97 *ac97, unsigned short reg,
+		unsigned short val)
+{
+	struct atmel_ac97c *chip = get_chip(ac97);
+	unsigned long word;
+	int timeout = 40;
+
+	word = (reg & 0x7f) << 16 | val;
+
+	do {
+		if (ac97c_readl(chip, COSR) & AC97C_CSR_TXRDY) {
+			ac97c_writel(chip, COTHR, word);
+			return;
+		}
+		udelay(1);
+	} while (--timeout);
+
+	dev_dbg(&chip->pdev->dev, "codec write timeout\n");
+}
+
+static unsigned short atmel_ac97c_read(struct snd_ac97 *ac97,
+		unsigned short reg)
+{
+	struct atmel_ac97c *chip = get_chip(ac97);
+	unsigned long word;
+	int timeout = 40;
+	int write = 10;
+
+	word = (0x80 | (reg & 0x7f)) << 16;
+
+	if ((ac97c_readl(chip, COSR) & AC97C_CSR_RXRDY) != 0)
+		ac97c_readl(chip, CORHR);
+
+retry_write:
+	timeout = 40;
+
+	do {
+		if ((ac97c_readl(chip, COSR) & AC97C_CSR_TXRDY) != 0) {
+			ac97c_writel(chip, COTHR, word);
+			goto read_reg;
+		}
+		udelay(10);
+	} while (--timeout);
+
+	if (!--write)
+		goto timed_out;
+	goto retry_write;
+
+read_reg:
+	do {
+		if ((ac97c_readl(chip, COSR) & AC97C_CSR_RXRDY) != 0) {
+			unsigned short val = ac97c_readl(chip, CORHR);
+			return val;
+		}
+		udelay(10);
+	} while (--timeout);
+
+	if (!--write)
+		goto timed_out;
+	goto retry_write;
+
+timed_out:
+	dev_dbg(&chip->pdev->dev, "codec read timeout\n");
+	return 0xffff;
+}
+
+static bool filter(struct dma_chan *chan, void *slave)
+{
+	struct dw_dma_slave *dws = slave;
+
+	if (dws->dma_dev == chan->device->dev) {
+		chan->private = dws;
+		return true;
+	} else
+		return false;
+}
+
+static void atmel_ac97c_reset(struct atmel_ac97c *chip)
+{
+	ac97c_writel(chip, MR, AC97C_MR_WRST);
+
+	if (gpio_is_valid(chip->reset_pin)) {
+		gpio_set_value(chip->reset_pin, 0);
+		/* AC97 v2.2 specifications says minimum 1 us. */
+		udelay(10);
+		gpio_set_value(chip->reset_pin, 1);
+	}
+
+	udelay(1);
+	ac97c_writel(chip, MR, AC97C_MR_ENA);
+}
+
+static int __devinit atmel_ac97c_probe(struct platform_device *pdev)
+{
+	struct snd_card			*card;
+	struct atmel_ac97c		*chip;
+	struct resource			*regs;
+	struct ac97c_platform_data	*pdata;
+	struct clk			*pclk;
+	static struct snd_ac97_bus_ops	ops = {
+		.write	= atmel_ac97c_write,
+		.read	= atmel_ac97c_read,
+	};
+	int				retval;
+
+	regs = platform_get_resource(pdev, IORESOURCE_MEM, 0);
+	if (!regs) {
+		dev_dbg(&pdev->dev, "no memory resource\n");
+		return -ENXIO;
+	}
+
+	pdata = pdev->dev.platform_data;
+	if (!pdata) {
+		dev_dbg(&pdev->dev, "no platform data\n");
+		return -ENXIO;
+	}
+
+	pclk = clk_get(&pdev->dev, "pclk");
+	if (IS_ERR(pclk)) {
+		dev_dbg(&pdev->dev, "no peripheral clock\n");
+		return PTR_ERR(pclk);
+	}
+	clk_enable(pclk);
+
+	retval = snd_card_create(SNDRV_DEFAULT_IDX1, SNDRV_DEFAULT_STR1,
+			THIS_MODULE, sizeof(struct atmel_ac97c), &card);
+	if (retval) {
+		dev_dbg(&pdev->dev, "could not create sound card device\n");
+		goto err_snd_card_new;
+	}
+
+	chip = get_chip(card);
+
+	spin_lock_init(&chip->lock);
+
+	strcpy(card->driver, "Atmel AC97C");
+	strcpy(card->shortname, "Atmel AC97C");
+	sprintf(card->longname, "Atmel AC97 controller");
+
+	chip->card = card;
+	chip->pclk = pclk;
+	chip->pdev = pdev;
+	chip->regs = ioremap(regs->start, regs->end - regs->start + 1);
+
+	if (!chip->regs) {
+		dev_dbg(&pdev->dev, "could not remap register memory\n");
+		goto err_ioremap;
+	}
+
+	if (gpio_is_valid(pdata->reset_pin)) {
+		if (gpio_request(pdata->reset_pin, "reset_pin")) {
+			dev_dbg(&pdev->dev, "reset pin not available\n");
+			chip->reset_pin = -ENODEV;
+		} else {
+			gpio_direction_output(pdata->reset_pin, 1);
+			chip->reset_pin = pdata->reset_pin;
+		}
+	}
+
+	snd_card_set_dev(card, &pdev->dev);
+
+	retval = snd_ac97_bus(card, 0, &ops, chip, &chip->ac97_bus);
+	if (retval) {
+		dev_dbg(&pdev->dev, "could not register on ac97 bus\n");
+		goto err_ac97_bus;
+	}
+
+	atmel_ac97c_reset(chip);
+
+	retval = atmel_ac97c_mixer_new(chip);
+	if (retval) {
+		dev_dbg(&pdev->dev, "could not register ac97 mixer\n");
+		goto err_ac97_bus;
+	}
+
+	if (pdata->rx_dws.dma_dev) {
+		struct dw_dma_slave *dws = &pdata->rx_dws;
+		dma_cap_mask_t mask;
+
+		dws->rx_reg = regs->start + AC97C_CARHR + 2;
+
+		dma_cap_zero(mask);
+		dma_cap_set(DMA_SLAVE, mask);
+
+		chip->dma.rx_chan = dma_request_channel(mask, filter, dws);
+
+		dev_info(&chip->pdev->dev, "using %s for DMA RX\n",
+					chip->dma.rx_chan->dev->device.bus_id);
+		set_bit(DMA_RX_CHAN_PRESENT, &chip->flags);
+	}
+
+	if (pdata->tx_dws.dma_dev) {
+		struct dw_dma_slave *dws = &pdata->tx_dws;
+		dma_cap_mask_t mask;
+
+		dws->tx_reg = regs->start + AC97C_CATHR + 2;
+
+		dma_cap_zero(mask);
+		dma_cap_set(DMA_SLAVE, mask);
+
+		chip->dma.tx_chan = dma_request_channel(mask, filter, dws);
+
+		dev_info(&chip->pdev->dev, "using %s for DMA TX\n",
+					chip->dma.tx_chan->dev->device.bus_id);
+		set_bit(DMA_TX_CHAN_PRESENT, &chip->flags);
+	}
+
+	if (!test_bit(DMA_RX_CHAN_PRESENT, &chip->flags) &&
+			!test_bit(DMA_TX_CHAN_PRESENT, &chip->flags)) {
+		dev_dbg(&pdev->dev, "DMA not available\n");
+		retval = -ENODEV;
+		goto err_dma;
+	}
+
+	retval = atmel_ac97c_pcm_new(chip);
+	if (retval) {
+		dev_dbg(&pdev->dev, "could not register ac97 pcm device\n");
+		goto err_dma;
+	}
+
+	retval = snd_card_register(card);
+	if (retval) {
+		dev_dbg(&pdev->dev, "could not register sound card\n");
+		goto err_ac97_bus;
+	}
+
+	platform_set_drvdata(pdev, card);
+
+	dev_info(&pdev->dev, "Atmel AC97 controller at 0x%p\n",
+			chip->regs);
+
+	return 0;
+
+err_dma:
+	if (test_bit(DMA_RX_CHAN_PRESENT, &chip->flags))
+		dma_release_channel(chip->dma.rx_chan);
+	if (test_bit(DMA_TX_CHAN_PRESENT, &chip->flags))
+		dma_release_channel(chip->dma.tx_chan);
+	clear_bit(DMA_RX_CHAN_PRESENT, &chip->flags);
+	clear_bit(DMA_TX_CHAN_PRESENT, &chip->flags);
+	chip->dma.rx_chan = NULL;
+	chip->dma.tx_chan = NULL;
+err_ac97_bus:
+	snd_card_set_dev(card, NULL);
+
+	if (gpio_is_valid(chip->reset_pin))
+		gpio_free(chip->reset_pin);
+
+	iounmap(chip->regs);
+err_ioremap:
+	snd_card_free(card);
+err_snd_card_new:
+	clk_disable(pclk);
+	clk_put(pclk);
+	return retval;
+}
+
+#ifdef CONFIG_PM
+static int atmel_ac97c_suspend(struct platform_device *pdev, pm_message_t msg)
+{
+	struct snd_card *card = platform_get_drvdata(pdev);
+	struct atmel_ac97c *chip = card->private_data;
+
+	if (test_bit(DMA_RX_READY, &chip->flags))
+		dw_dma_cyclic_stop(chip->dma.rx_chan);
+	if (test_bit(DMA_TX_READY, &chip->flags))
+		dw_dma_cyclic_stop(chip->dma.tx_chan);
+	clk_disable(chip->pclk);
+
+	return 0;
+}
+
+static int atmel_ac97c_resume(struct platform_device *pdev)
+{
+	struct snd_card *card = platform_get_drvdata(pdev);
+	struct atmel_ac97c *chip = card->private_data;
+
+	clk_enable(chip->pclk);
+	if (test_bit(DMA_RX_READY, &chip->flags))
+		dw_dma_cyclic_start(chip->dma.rx_chan);
+	if (test_bit(DMA_TX_READY, &chip->flags))
+		dw_dma_cyclic_start(chip->dma.tx_chan);
+
+	return 0;
+}
+#else
+#define atmel_ac97c_suspend NULL
+#define atmel_ac97c_resume NULL
+#endif
+
+static int __devexit atmel_ac97c_remove(struct platform_device *pdev)
+{
+	struct snd_card *card = platform_get_drvdata(pdev);
+	struct atmel_ac97c *chip = get_chip(card);
+
+	if (gpio_is_valid(chip->reset_pin))
+		gpio_free(chip->reset_pin);
+
+	clk_disable(chip->pclk);
+	clk_put(chip->pclk);
+	iounmap(chip->regs);
+
+	if (test_bit(DMA_RX_CHAN_PRESENT, &chip->flags))
+		dma_release_channel(chip->dma.rx_chan);
+	if (test_bit(DMA_TX_CHAN_PRESENT, &chip->flags))
+		dma_release_channel(chip->dma.tx_chan);
+	clear_bit(DMA_RX_CHAN_PRESENT, &chip->flags);
+	clear_bit(DMA_TX_CHAN_PRESENT, &chip->flags);
+	chip->dma.rx_chan = NULL;
+	chip->dma.tx_chan = NULL;
+
+	snd_card_set_dev(card, NULL);
+	snd_card_free(card);
+
+	platform_set_drvdata(pdev, NULL);
+
+	return 0;
+}
+
+static struct platform_driver atmel_ac97c_driver = {
+	.remove		= __devexit_p(atmel_ac97c_remove),
+	.driver		= {
+		.name	= "atmel_ac97c",
+	},
+	.suspend	= atmel_ac97c_suspend,
+	.resume		= atmel_ac97c_resume,
+};
+
+static int __init atmel_ac97c_init(void)
+{
+	return platform_driver_probe(&atmel_ac97c_driver,
+			atmel_ac97c_probe);
+}
+module_init(atmel_ac97c_init);
+
+static void __exit atmel_ac97c_exit(void)
+{
+	platform_driver_unregister(&atmel_ac97c_driver);
+}
+module_exit(atmel_ac97c_exit);
+
+MODULE_LICENSE("GPL");
+MODULE_DESCRIPTION("Driver for Atmel AC97 controller");
+MODULE_AUTHOR("Hans-Christian Egtvedt <hans-christian.egtvedt@atmel.com>");