ENGR00066775 i.mx37 spdif driver development

Add spdif tx driver
DMA mode
transfer bit: 16bit/32bit

Signed-off-by: Wallace Wang <r59996@freescale.com>

3 files changed, 1162 insertions, 0 deletions

diff --git a/sound/arm/Kconfig b/sound/arm/Kconfig
index abac8a9f0182..7cd013b65c3b 100644
--- a/sound/arm/Kconfig
+++ b/sound/arm/Kconfig
@@ -3,6 +3,12 @@
 menu "ALSA ARM devices"
 	depends on SND!=n && ARM
 
+config SND_MXC_SPDIF
+        tristate "MXC SPDIF sound card spports"
+        select SND_PCM
+        help
+          Say Y here to enable SPDIF sound card
+
 config SND_SA11XX_UDA1341
 	tristate "SA11xx UDA1341TS driver (iPaq H3600)"
 	depends on ARCH_SA1100 && SND && L3
diff --git a/sound/arm/Makefile b/sound/arm/Makefile
index 33a552ce125c..a8a75b5da3d0 100644
--- a/sound/arm/Makefile
+++ b/sound/arm/Makefile
@@ -19,3 +19,6 @@ snd-pxa2xx-ac97-objs		:= pxa2xx-ac97.o
 #
 CFLAGS_mxc-alsa-pmic.o  = -I$(TOPDIR)/drivers/mxc
 obj-$(CONFIG_SND_MXC_PMIC)	+= mxc-alsa-pmic.o mxc-alsa-mixer.o
+
+CFLGS_mxc_alsa_spdif.o = -I$(TOPDIR)/drivers/mxc
+obj-$(CONFIG_SND_MXC_SPDIF)	+= mxc-alsa-spdif.o
diff --git a/sound/arm/mxc-alsa-spdif.c b/sound/arm/mxc-alsa-spdif.c
new file mode 100644
index 000000000000..3666ad3b6a1b
--- /dev/null
+++ b/sound/arm/mxc-alsa-spdif.c
@@ -0,0 +1,1153 @@
+/*
+ * Copyright 2007-2008 Freescale Semiconductor, Inc. All Rights Reserved.
+ */
+
+/*
+ * The code contained herein is licensed under the GNU General Public
+ * License. You may obtain a copy of the GNU General Public License
+ * Version 2 or later at the following locations:
+ *
+ * http://www.opensource.org/licenses/gpl-license.html
+ * http://www.gnu.org/copyleft/gpl.html
+ */
+
+/*!
+ * @defgroup SOUND_DRV MXC Sound Driver for ALSA
+ */
+
+/*!
+ * @file       mxc-alsa-spdif.c
+ * @brief      this fle       mxc-alsa-spdif.c
+ * @brief      this file implements mxc alsa driver for spdif.
+ *             The spdif tx supports consumer channel for linear PCM and
+ *	       compressed audio data. The supported sample rates are
+ *	       48KHz, 44.1KHz and 32KHz.
+ *
+ * @ingroup SOUND_DRV
+ */
+
+#include <sound/driver.h>
+#include <linux/module.h>
+#include <linux/moduleparam.h>
+#include <linux/platform_device.h>
+#include <linux/init.h>
+#include <linux/errno.h>
+#include <linux/ioctl.h>
+#include <linux/delay.h>
+#include <linux/slab.h>
+#include <linux/dma-mapping.h>
+#include <linux/soundcard.h>
+#include <linux/clk.h>
+#ifdef CONFIG_PM
+#include <linux/pm.h>
+#endif
+
+#include <asm/arch/dma.h>
+#include <asm/mach-types.h>
+#include <asm/io.h>
+#include <asm/irq.h>
+
+#include <sound/core.h>
+#include <sound/pcm.h>
+#include <sound/asoundef.h>
+#include <sound/initval.h>
+#include <sound/control.h>
+
+#define MXC_SPDIF_NAME "MXC_SPDIF"
+
+#define SPDIF_MAX_BUF_SIZE      (32*1024)
+#define SPDIF_DMA_BUF_SIZE	(8*1024)
+#define SPDIF_MIN_PERIOD_SIZE	64
+#define SPDIF_MIN_PERIOD	2
+#define SPDIF_MAX_PERIOD	255
+
+#define SPDIF_REG_SCR   0x00
+#define SPDIF_REG_SIE   0x0C
+#define SPDIF_REG_SIS   0x10
+#define SPDIF_REG_SIC   0x10
+#define SPDIF_REG_STL   0x2C
+#define SPDIF_REG_STR   0x30
+#define SPDIF_REG_STCSCH        0x34
+#define SPDIF_REG_STCSCL        0x38
+#define SPDIF_REG_STC   0x50
+
+/* SPDIF Configuration register */
+#define SCR_TXFIFO_AUTOSYNC     (1 << 17)
+#define SCR_TXFIFO_ZERO         (0 << 10)
+#define SCR_TXFIFO_NORMAL       (1 << 10)
+#define SCR_TXFIFO_ONESAMPLE    (2 << 10)
+#define SCR_DMA_TX_ENABLE       (1 << 8)
+#define SCR_DMA_TX_DISABLE      (0 << 8)
+#define SCR_TXSEL_OFF           (0 << 2)
+#define SCR_TXSEL_RX            (1 << 2)
+#define SCR_TXSEL_NORMAL        (5 << 2)
+
+#define INT_TXFIFO_UNOV         (1 << 19)
+#define INT_TXFIFO_RESYNC       (1 << 18)
+#define INT_TX_EMPTY            (1 << 1)
+
+enum spdif_clk_accuracy {
+	SPDIF_CLK_ACCURACY_LEV2 = 0,
+	SPDIF_CLK_ACCURACY_LEV1 = 2,
+	SPDIF_CLK_ACCURACY_LEV3 = 1,
+	SPDIF_CLK_ACCURACY_RESV = 3
+};
+
+enum spdif_max_wdl {
+	SPDIF_MAX_WDL_20,
+	SPDIF_MAX_WDL_24
+};
+
+enum spdif_wdl {
+	SPDIF_WDL_DEFAULT = 0,
+	SPDIF_WDL_FIFTH = 4,
+	SPDIF_WDL_FOURTH = 3,
+	SPDIF_WDL_THIRD = 2,
+	SPDIF_WDL_SECOND = 1,
+	SPDIF_WDL_MAX = 5
+};
+
+static unsigned long spdif_base_addr;
+
+/*!
+ * @brief Enable/Disable spdif DMA request
+ *
+ * This function is called to enable or disable the dma transfer
+ */
+static int spdif_txdma_cfg(int txdma)
+{
+	unsigned long value;
+
+	value = __raw_readl(SPDIF_REG_SCR + spdif_base_addr) & 0xfffeff;
+	value |= txdma;
+	__raw_writel(value, SPDIF_REG_SCR + spdif_base_addr);
+
+	return 0;
+}
+
+/*!
+ * @brief Enable spdif interrupt
+ *
+ * This function is called to enable relevant interrupts.
+ */
+static int spdif_intr_enable(int intr)
+{
+	unsigned long value;
+
+	value = __raw_readl(SPDIF_REG_SIE + spdif_base_addr) & 0xffffff;
+	value |= intr;
+	__raw_writel(value, SPDIF_REG_SIE + spdif_base_addr);
+
+	return 0;
+}
+
+/*!
+ * @brief Disable spdif interrupt
+ *
+ * This function is called to diable relevant interrupts.
+ */
+static int spdif_intr_disable(int intr)
+{
+	unsigned long value;
+
+	value = __raw_readl(SPDIF_REG_SIE + spdif_base_addr) & 0xffffff;
+	value &= ~intr;
+	__raw_writel(value, SPDIF_REG_SIE + spdif_base_addr);
+
+	return 0;
+}
+
+/*!
+ * @brief Set the clock accuracy level in the channel bit
+ *
+ * This function is called to set the clock accuracy level
+ */
+static int spdif_set_clk_accuracy(enum spdif_clk_accuracy level)
+{
+	unsigned long value;
+
+	value = __raw_readl(SPDIF_REG_STCSCL + spdif_base_addr) & 0xffffcf;
+	value |= (level << 4);
+	__raw_writel(value, SPDIF_REG_STCSCL + spdif_base_addr);
+
+	return 0;
+}
+
+/*!
+ * @brief Set the audio sample rate in the channel status bit
+ *
+ * This function is called to set the audio sample rate to be transfered.
+ */
+static int spdif_set_sample_rate(int src_44100, int src_48000, int sample_rate)
+{
+	unsigned long value;
+
+	value = __raw_readl(SPDIF_REG_STCSCL + spdif_base_addr) & 0xfffff0;
+
+	switch (sample_rate) {
+	case 44100:
+		__raw_writel(value, SPDIF_REG_STCSCL + spdif_base_addr);
+		value = (src_44100 << 8) | 0x07;
+		__raw_writel(value, SPDIF_REG_STC + spdif_base_addr);
+		break;
+	case 48000:
+		value |= 0x04;
+		__raw_writel(value, SPDIF_REG_STCSCL + spdif_base_addr);
+		value = (src_48000 << 8) | 0x07;
+		__raw_writel(value, SPDIF_REG_STC + spdif_base_addr);
+		break;
+	case 32000:
+		value |= 0x0c;
+		__raw_writel(value, SPDIF_REG_STCSCL + spdif_base_addr);
+		value = (src_48000 << 8) | 0x0b;
+		__raw_writel(value, SPDIF_REG_STC + spdif_base_addr);
+		break;
+	}
+
+	return 0;
+}
+
+/*!
+ * @brief Set the lchannel status bit
+ *
+ * This function is called to set the channel status
+ */
+static int spdif_set_channel_status(int value, unsigned long reg)
+{
+	__raw_writel(value & 0xffffff, reg + spdif_base_addr);
+
+	return 0;
+}
+
+/*!
+ * @brief Get spdif interrupt status and clear the interrupt
+ *
+ * This function is called to check relevant interrupt status
+ */
+static int spdif_intr_status(void)
+{
+	unsigned long value;
+
+	value = __raw_readl(SPDIF_REG_SIS + spdif_base_addr) & 0xffffff;
+
+	__raw_writel(0, SPDIF_REG_SIC + spdif_base_addr);
+
+	return value;
+}
+
+/*!
+ * @brief spdif interrupt handler
+ */
+static irqreturn_t spdif_isr(int irq, void *dev_id)
+{
+	unsigned long status, value;
+
+	status = spdif_intr_status();
+	value = __raw_readl(SPDIF_REG_SIE + spdif_base_addr);
+
+	if ((value & (1 << 19)) && (status & 0x80000))
+		pr_info("spdif tx underrun\n");
+	else if ((value & (1 << 18)) && (status & 0x40000))
+		pr_info("spdif tx resync\n");
+	else if ((value & (1 << 1)) && (status & 0x2))
+		pr_info("spdif tx fifo empty\n");
+
+	return IRQ_HANDLED;
+}
+
+/*!
+ * @brief Initialize spdif module
+ *
+ * This function is called to set the spdif to initial state.
+ */
+static int spdif_tx_init(void)
+{
+	unsigned long value;
+
+	value = 0x20514;
+	__raw_writel(value, SPDIF_REG_SCR + spdif_base_addr);
+
+	value = 0xc0000;
+	/*Spdif has no watermark, so the underrun interrupt can't be enabled */
+	/*__raw_writel(value, SPDIF_REG_SIE);*/
+
+	/* Default clock source from EXTAL, divider by 8, generate 44.1kHz
+	   sample rate */
+	value = 0x07;
+	__raw_writel(value, SPDIF_REG_STC + spdif_base_addr);
+
+	/* spdif intrrupt bug */
+	if (request_irq(MXC_INT_SPDIF, spdif_isr, 0, "spdif", NULL))
+		return -1;
+
+	return 0;
+
+}
+
+/*!
+ * @brief deinitialize spdif module
+ *
+ * This function is called to stop the spdif
+ */
+static int spdif_tx_exit(void)
+{
+	int value;
+
+	value = __raw_readl(SPDIF_REG_SCR + spdif_base_addr) & 0xffffe3;
+	value |= SCR_TXSEL_OFF;
+	__raw_writel(value, SPDIF_REG_SCR + spdif_base_addr);
+	disable_irq(MXC_INT_SPDIF);
+	free_irq(MXC_INT_SPDIF, NULL);
+
+	return 0;
+}
+
+/*!
+ * This structure represents an audio stream in term of
+ * channel DMA, HW configuration on spdif controller.
+ */
+struct mxc_spdif_stream {
+
+	/*!
+	 * identification string
+	 */
+	char *id;
+	/*!
+	 * device identifier for DMA
+	 */
+	int dma_wchannel;
+	/*!
+	 * we are using this stream for transfer now
+	 */
+	int active:1;
+	/*!
+	 * current transfer period
+	 */
+	int period;
+	/*!
+	 * current count of transfered periods
+	 */
+	int periods;
+	/*!
+	 * are we recording - flag used to do DMA trans. for sync
+	 */
+	int tx_spin;
+	/*!
+	 * for locking in DMA operations
+	 */
+	spinlock_t dma_lock;
+	/*!
+	 * Alsa substream pointer
+	 */
+	struct snd_pcm_substream *stream;
+};
+
+struct spdif_mixer_control {
+
+	/*!
+	 * IEC958 channel status bit
+	 */
+	unsigned char ch_status[4];
+};
+
+struct mxc_spdif_device {
+	/*!
+	 * SPDIF module register base address
+	 */
+	unsigned long __iomem *reg_base;
+
+	/*!
+	 * spdif tx available or not
+	 */
+	int mxc_spdif_tx;
+
+	/*!
+	 * spdif rx available or not
+	 */
+	int mxc_spdif_rx;
+
+	/*!
+	 * spdif 44100 clock src
+	 */
+	int spdif_txclk_44100;
+
+	/*!
+	 * spdif 48000 clock src
+	 */
+	int spdif_txclk_48000;
+
+	/*!
+	 * ALSA SPDIF sound card handle
+	 */
+	struct snd_card *card;
+
+	/*!
+	 * ALSA spdif driver type handle
+	 */
+	struct snd_pcm *pcm;
+
+	struct mxc_spdif_stream s[2];
+};
+
+static struct spdif_mixer_control mxc_spdif_control;
+
+static unsigned int spdif_playback_rates[] = { 32000, 44100, 48000 };
+
+/*!
+  * this structure represents the sample rates supported
+  * by SPDIF
+  */
+static struct snd_pcm_hw_constraint_list hw_playback_rates_stereo = {
+	.count = ARRAY_SIZE(spdif_playback_rates),
+	.list = spdif_playback_rates,
+	.mask = 0,
+};
+
+/*!
+  * This function configures the DMA channel used to transfer
+  * audio from MCU to SPDIF or from SPDIF to MCU
+  *
+  * @param	s	pointer to the structure of the current stream.
+  * @param      callback        pointer to function that will be
+  *                              called when a SDMA TX transfer finishes.
+  *
+  * @return              0 on success, -1 otherwise.
+  */
+static int
+spdif_configure_dma_channel(struct mxc_spdif_stream *s,
+			    mxc_dma_callback_t callback)
+{
+	int ret = -1;
+	int channel = -1;
+
+	if (s->dma_wchannel != 0)
+		mxc_dma_free(s->dma_wchannel);
+
+	if (s->stream->stream == SNDRV_PCM_STREAM_PLAYBACK) {
+		if (s->stream->runtime->sample_bits > 16) {
+			channel =
+			    mxc_dma_request(MXC_DMA_SPDIF_32BIT_TX,
+					    "SPDIF TX DMA");
+		} else {
+			channel =
+			    mxc_dma_request(MXC_DMA_SPDIF_16BIT_TX,
+					    "SPDIF TX DMA");
+		}
+
+		pr_debug("spdif_configure_dma_channel: %d\n", channel);
+	} else if (s->stream->stream == SNDRV_PCM_STREAM_CAPTURE) {
+
+	}
+	ret = mxc_dma_callback_set(channel,
+				   (mxc_dma_callback_t) callback, (void *)s);
+	if (ret != 0) {
+		pr_info("spdif_configure_dma_channel - err\n");
+		mxc_dma_free(channel);
+		return -1;
+	}
+	s->dma_wchannel = channel;
+	return 0;
+}
+
+/*!
+  * This function gets the dma pointer position during playback.
+  * Our DMA implementation does not allow to retrieve this position
+  * when a transfert is active, so, it answers the middle of
+  * the current period beeing transfered
+  *
+  * @param	s	pointer to the structure of the current stream.
+  *
+  */
+static u_int spdif_get_playback_dma_pos(struct mxc_spdif_stream *s)
+{
+	struct snd_pcm_substream *substream;
+	struct snd_pcm_runtime *runtime;
+	unsigned int offset = 0;
+	substream = s->stream;
+	runtime = substream->runtime;
+
+	/* tx_spin value is used here to check if a transfer is active */
+	if (s->tx_spin) {
+		offset =
+		    (runtime->period_size * (s->periods)) +
+		    (runtime->period_size >> 1);
+		if (offset >= runtime->buffer_size)
+			offset = runtime->period_size >> 1;
+		pr_debug("MXC: audio_get_dma_pos offset  %d, buffer_size %d\n",
+			 offset, (int)runtime->buffer_size);
+	} else {
+		offset = (runtime->period_size * (s->periods));
+		if (offset >= runtime->buffer_size)
+			offset = 0;
+		pr_debug
+		    ("MXC: spdif_get_dma_pos BIS offset  %d, buffer_size %d\n",
+		     offset, (int)runtime->buffer_size);
+	}
+	return offset;
+}
+
+/*!
+  * This function stops the current dma transfert for playback
+  * and clears the dma pointers.
+  *
+  * @param	s	pointer to the structure of the current stream.
+  *
+  */
+static void spdif_stop_tx(struct mxc_spdif_stream *s)
+{
+	unsigned long flags;
+	struct snd_pcm_substream *substream;
+	struct snd_pcm_runtime *runtime;
+	unsigned int dma_size;
+	unsigned int offset;
+	substream = s->stream;
+	runtime = substream->runtime;
+	dma_size = frames_to_bytes(runtime, runtime->period_size);
+	offset = dma_size * s->periods;
+	spin_lock_irqsave(&s->dma_lock, flags);
+	s->active = 0;
+	s->period = 0;
+	s->periods = 0;
+
+	/* this stops the dma channel and clears the buffer ptrs */
+	mxc_dma_disable(s->dma_wchannel);
+	spdif_txdma_cfg(SCR_DMA_TX_DISABLE);
+	dma_unmap_single(NULL, runtime->dma_addr + offset, dma_size,
+			 DMA_TO_DEVICE);
+	spin_unlock_irqrestore(&s->dma_lock, flags);
+}
+
+/*!
+  * This function is called whenever a new audio block needs to be
+  * transferred to SPDIF. The function receives the address and the size
+  * of the new block and start a new DMA transfer.
+  *
+  * @param	s	pointer to the structure of the current stream.
+  *
+  */
+static void spdif_start_tx(struct mxc_spdif_stream *s)
+{
+	struct snd_pcm_substream *substream;
+	struct snd_pcm_runtime *runtime;
+	unsigned int dma_size = 0;
+	unsigned int offset;
+	int ret = 0;
+	mxc_dma_requestbuf_t dma_request;
+	substream = s->stream;
+	runtime = substream->runtime;
+	memset(&dma_request, 0, sizeof(mxc_dma_requestbuf_t));
+	if (s->active) {
+		dma_size = frames_to_bytes(runtime, runtime->period_size);
+		offset = dma_size * s->period;
+		dma_request.src_addr =
+		    (dma_addr_t) (dma_map_single
+				  (NULL, runtime->dma_area + offset, dma_size,
+				   DMA_TO_DEVICE));
+
+		dma_request.dst_addr = (dma_addr_t) (SPDIF_BASE_ADDR + 0x2c);
+
+		dma_request.num_of_bytes = dma_size;
+		mxc_dma_config(s->dma_wchannel, &dma_request, 1,
+			       MXC_DMA_MODE_WRITE);
+		ret = mxc_dma_enable(s->dma_wchannel);
+		spdif_txdma_cfg(SCR_DMA_TX_ENABLE);
+		s->tx_spin = 1;
+		if (ret) {
+			pr_info("audio_process_dma: cannot queue DMA \
+				buffer\n");
+			return;
+		}
+		s->period++;
+		s->period %= runtime->periods;
+
+		if ((s->period > s->periods)
+		    && ((s->period - s->periods) > 1)) {
+			pr_debug("audio playback chain dma: already double \
+				buffered\n");
+			return;
+		}
+
+		if ((s->period < s->periods)
+		    && ((s->period + runtime->periods - s->periods) > 1)) {
+			pr_debug("audio playback chain dma: already double  \
+				buffered\n");
+			return;
+		}
+
+		if (s->period == s->periods) {
+			pr_debug("audio playback chain dma: s->period == \
+				s->periods\n");
+			return;
+		}
+
+		if (snd_pcm_playback_hw_avail(runtime) <
+		    2 * runtime->period_size) {
+			pr_debug("audio playback chain dma: available data \
+				is not enough\n");
+			return;
+		}
+
+		pr_debug
+		    ("audio playback chain dma:to set up the 2nd dma buffer\n");
+
+		offset = dma_size * s->period;
+		dma_request.src_addr =
+		    (dma_addr_t) (dma_map_single
+				  (NULL, runtime->dma_area + offset, dma_size,
+				   DMA_TO_DEVICE));
+		mxc_dma_config(s->dma_wchannel, &dma_request, 1,
+			       MXC_DMA_MODE_WRITE);
+		ret = mxc_dma_enable(s->dma_wchannel);
+		s->period++;
+		s->period %= runtime->periods;
+
+	}
+	return;
+}
+
+/*!
+  * This is a callback which will be called
+  * when a TX transfer finishes. The call occurs
+  * in interrupt context.
+  *
+  * @param	data	pointer to the structure of the current stream
+  * @param	error	DMA error flag
+  * @param	count	number of bytes transfered by the DMA
+  */
+static void spdif_tx_callback(void *data, int error, unsigned int count)
+{
+	struct mxc_spdif_stream *s;
+	struct snd_pcm_substream *substream;
+	struct snd_pcm_runtime *runtime;
+	unsigned int dma_size;
+	unsigned int previous_period;
+	unsigned int offset;
+	s = data;
+	substream = s->stream;
+	runtime = substream->runtime;
+	previous_period = s->periods;
+	dma_size = frames_to_bytes(runtime, runtime->period_size);
+	offset = dma_size * previous_period;
+	s->tx_spin = 0;
+	s->periods++;
+	s->periods %= runtime->periods;
+	dma_unmap_single(NULL, runtime->dma_addr + offset, dma_size,
+			 DMA_TO_DEVICE);
+	if (s->active)
+		snd_pcm_period_elapsed(s->stream);
+	spin_lock(&s->dma_lock);
+	spdif_start_tx(s);
+	spin_unlock(&s->dma_lock);
+}
+
+/*!
+  * This function is a dispatcher of command to be executed
+  * by the driver for playback.
+  *
+  * @param	substream	pointer to the structure of the current stream.
+  * @param	cmd		command to be executed
+  *
+  * @return              0 on success, -1 otherwise.
+  */
+static int
+snd_mxc_spdif_playback_trigger(struct snd_pcm_substream *substream, int cmd)
+{
+	struct mxc_spdif_device *chip;
+	struct mxc_spdif_stream *s;
+	int err = 0;
+	chip = snd_pcm_substream_chip(substream);
+	s = &chip->s[SNDRV_PCM_STREAM_PLAYBACK];
+	spin_lock(&s->dma_lock);
+	switch (cmd) {
+	case SNDRV_PCM_TRIGGER_START:
+		s->tx_spin = 0;
+		s->active = 1;
+		spdif_start_tx(s);
+		break;
+	case SNDRV_PCM_TRIGGER_STOP:
+		spdif_stop_tx(s);
+		break;
+	case SNDRV_PCM_TRIGGER_SUSPEND:
+		s->active = 0;
+		s->periods = 0;
+		break;
+	case SNDRV_PCM_TRIGGER_RESUME:
+		s->active = 1;
+		s->tx_spin = 0;
+		spdif_start_tx(s);
+		break;
+	case SNDRV_PCM_TRIGGER_PAUSE_PUSH:
+		s->active = 0;
+		break;
+	case SNDRV_PCM_TRIGGER_PAUSE_RELEASE:
+		s->active = 1;
+		s->tx_spin = 0;
+		spdif_start_tx(s);
+		break;
+	default:
+		err = -EINVAL;
+		break;
+	}
+	spin_unlock(&s->dma_lock);
+	return err;
+}
+
+/*!
+  * This function configures the hardware to allow audio
+  * playback operations. It is called by ALSA framework.
+  *
+  * @param	substream	pointer to the structure of the current stream.
+  *
+  * @return              0 on success, -1 otherwise.
+  */
+static int snd_mxc_spdif_playback_prepare(struct snd_pcm_substream *substream)
+{
+	struct mxc_spdif_device *chip;
+	struct snd_pcm_runtime *runtime;
+	int err;
+	unsigned int ch_status;
+	chip = snd_pcm_substream_chip(substream);
+	runtime = substream->runtime;
+	spdif_tx_init();
+	ch_status =
+	    ((mxc_spdif_control.ch_status[2] << 16) | (mxc_spdif_control.
+						       ch_status[1] << 8) |
+	     mxc_spdif_control.ch_status[0]);
+	spdif_set_channel_status(ch_status, SPDIF_REG_STCSCH);
+	ch_status = mxc_spdif_control.ch_status[3];
+	spdif_set_channel_status(ch_status, SPDIF_REG_STCSCL);
+	spdif_intr_enable(INT_TXFIFO_RESYNC);
+	spdif_set_sample_rate(chip->spdif_txclk_44100, chip->spdif_txclk_48000,
+			      runtime->rate);
+	spdif_set_clk_accuracy(SPDIF_CLK_ACCURACY_LEV2);
+	/* setup DMA controller for spdif tx */
+	err = spdif_configure_dma_channel(&chip->
+					  s[SNDRV_PCM_STREAM_PLAYBACK],
+					  spdif_tx_callback);
+	if (err < 0) {
+		pr_info("snd_mxc_spdif_playback_prepare - err < 0\n");
+		return err;
+	}
+	return 0;
+}
+
+/*!
+  * This function gets the current playback pointer position.
+  * It is called by ALSA framework.
+  *
+  * @param	substream	pointer to the structure of the current stream.
+  *
+  */
+static snd_pcm_uframes_t
+snd_mxc_spdif_playback_pointer(struct snd_pcm_substream *substream)
+{
+	struct mxc_spdif_device *chip;
+	chip = snd_pcm_substream_chip(substream);
+	return spdif_get_playback_dma_pos(&chip->s[SNDRV_PCM_STREAM_PLAYBACK]);
+}
+
+static struct snd_pcm_hardware snd_spdif_playback_hw = {
+	.info =
+	    (SNDRV_PCM_INFO_INTERLEAVED | SNDRV_PCM_INFO_BLOCK_TRANSFER |
+	     SNDRV_PCM_INFO_MMAP | SNDRV_PCM_INFO_HALF_DUPLEX |
+	     SNDRV_PCM_INFO_MMAP_VALID | SNDRV_PCM_INFO_PAUSE |
+	     SNDRV_PCM_INFO_RESUME),
+	.formats = SNDRV_PCM_FMTBIT_S16_LE | SNDRV_PCM_FMTBIT_S32_LE,
+	.rates =
+	    SNDRV_PCM_RATE_32000 | SNDRV_PCM_RATE_44100 | SNDRV_PCM_RATE_48000,
+	.rate_min = 32000,
+	.rate_max = 48000,
+	.channels_min = 2,
+	.channels_max = 2,
+	.buffer_bytes_max = SPDIF_MAX_BUF_SIZE,
+	.period_bytes_min = SPDIF_MIN_PERIOD_SIZE,
+	.period_bytes_max = SPDIF_DMA_BUF_SIZE,
+	.periods_min = SPDIF_MIN_PERIOD,
+	.periods_max = SPDIF_MAX_PERIOD,
+	.fifo_size = 0,
+};
+
+/*!
+  * This function opens a spdif device in playback mode
+  * It is called by ALSA framework.
+  *
+  * @param	substream	pointer to the structure of the current stream.
+  *
+  * @return              0 on success, -1 otherwise.
+  */
+static int snd_card_mxc_spdif_playback_open(struct snd_pcm_substream *substream)
+{
+	struct mxc_spdif_device *chip;
+	struct snd_pcm_runtime *runtime;
+	int err;
+	struct mxc_spdif_platform_data *spdif_data;
+
+	chip = snd_pcm_substream_chip(substream);
+	spdif_data = chip->card->dev->platform_data;
+	clk_enable(spdif_data->spdif_clk);
+	runtime = substream->runtime;
+	chip->s[SNDRV_PCM_STREAM_PLAYBACK].stream = substream;
+	runtime->hw = snd_spdif_playback_hw;
+	err = snd_pcm_hw_constraint_list(runtime, 0,
+					 SNDRV_PCM_HW_PARAM_RATE,
+					 &hw_playback_rates_stereo);
+	if (err < 0)
+		return err;
+	err =
+	    snd_pcm_hw_constraint_integer(runtime, SNDRV_PCM_HW_PARAM_PERIODS);
+	if (err < 0)
+		return err;
+	return 0;
+}
+
+/*!
+  * This function closes an spdif device for playback.
+  * It is called by ALSA framework.
+  *
+  * @param	substream	pointer to the structure of the current stream.
+  *
+  * @return              0 on success, -1 otherwise.
+  */
+static int snd_card_mxc_spdif_playback_close(struct snd_pcm_substream
+					     *substream)
+{
+	struct mxc_spdif_device *chip;
+	struct mxc_spdif_platform_data *spdif_data;
+
+	chip = snd_pcm_substream_chip(substream);
+	spdif_data = chip->card->dev->platform_data;
+	spdif_intr_disable(INT_TXFIFO_UNOV | INT_TXFIFO_RESYNC | INT_TX_EMPTY);
+	spdif_tx_exit();
+	clk_disable(spdif_data->spdif_clk);
+	mxc_dma_free(chip->s[SNDRV_PCM_STREAM_PLAYBACK].dma_wchannel);
+	chip->s[SNDRV_PCM_STREAM_PLAYBACK].dma_wchannel = 0;
+	return 0;
+}
+
+/*!
+  * This function configure the Audio HW in terms of memory allocation.
+  * It is called by ALSA framework.
+  *
+  * @param	substream	pointer to the structure of the current stream.
+  * @param	hw_params	Pointer to hardware paramters structure
+  *
+  * @return              0 on success, -1 otherwise.
+  */
+static int snd_mxc_spdif_hw_params(struct snd_pcm_substream
+				   *substream, struct snd_pcm_hw_params
+				   *hw_params)
+{
+	struct snd_pcm_runtime *runtime;
+	int ret = 0;
+	runtime = substream->runtime;
+	ret =
+	    snd_pcm_lib_malloc_pages(substream, params_buffer_bytes(hw_params));
+	if (ret < 0) {
+		pr_info("snd_mxc_spdif_hw_params - ret: %d\n", ret);
+		return ret;
+	}
+	runtime->dma_addr = virt_to_phys(runtime->dma_area);
+	return ret;
+}
+
+/*!
+  * This function frees the spdif hardware at the end of playback.
+  *
+  * @param	substream	pointer to the structure of the current stream.
+  *
+  * @return              0 on success, -1 otherwise.
+  */
+static int snd_mxc_spdif_hw_free(struct snd_pcm_substream *substream)
+{
+	return snd_pcm_lib_free_pages(substream);
+}
+
+/*!
+  * This structure is the list of operation that the driver
+  * must provide for the playback interface
+  */
+static struct snd_pcm_ops snd_card_mxc_spdif_playback_ops = {
+	.open = snd_card_mxc_spdif_playback_open,
+	.close = snd_card_mxc_spdif_playback_close,
+	.ioctl = snd_pcm_lib_ioctl,
+	.hw_params = snd_mxc_spdif_hw_params,
+	.hw_free = snd_mxc_spdif_hw_free,
+	.prepare = snd_mxc_spdif_playback_prepare,
+	.trigger = snd_mxc_spdif_playback_trigger,
+	.pointer = snd_mxc_spdif_playback_pointer,
+};
+
+static struct snd_pcm_ops snd_card_mxc_spdif_capture_ops = {
+	.open = NULL,
+	.close = NULL,
+	.ioctl = NULL,
+	.hw_params = NULL,
+	.hw_free = NULL,
+	.prepare = NULL,
+	.trigger = NULL,
+	.pointer = NULL,
+};
+
+/*!
+  * This functions initializes the playback audio device supported by
+  * spdif
+  *
+  * @param	mxc_spdif	pointer to the sound card structure.
+  *
+  */
+void mxc_init_spdif_device(struct mxc_spdif_device *mxc_spdif)
+{
+	if (mxc_spdif->mxc_spdif_tx) {
+		mxc_spdif->s[SNDRV_PCM_STREAM_PLAYBACK].id = "spdif tx";
+		mxc_spdif_control.ch_status[0] =
+		    IEC958_AES0_CON_NOT_COPYRIGHT |
+		    IEC958_AES0_CON_EMPHASIS_5015;
+		mxc_spdif_control.ch_status[1] = IEC958_AES1_CON_DIGDIGCONV_ID;
+		mxc_spdif_control.ch_status[2] = 0x00;
+		mxc_spdif_control.ch_status[3] =
+		    IEC958_AES3_CON_FS_44100 | IEC958_AES3_CON_CLOCK_1000PPM;
+	}
+	if (mxc_spdif->mxc_spdif_rx) {
+
+		/*Add code here if capture is available */
+	}
+
+}
+
+static int mxc_pb_spdif_info(struct snd_kcontrol *kcontrol,
+			     struct snd_ctl_elem_info *uinfo)
+{
+	uinfo->type = SNDRV_CTL_ELEM_TYPE_IEC958;
+	uinfo->count = 1;
+	return 0;
+}
+
+static int mxc_pb_spdif_get(struct snd_kcontrol *kcontrol,
+			    struct snd_ctl_elem_value *uvalue)
+{
+	uvalue->value.iec958.status[0] = mxc_spdif_control.ch_status[0];
+	uvalue->value.iec958.status[1] = mxc_spdif_control.ch_status[1];
+	uvalue->value.iec958.status[2] = mxc_spdif_control.ch_status[2];
+	uvalue->value.iec958.status[3] = mxc_spdif_control.ch_status[3];
+	return 0;
+}
+
+static int mxc_pb_spdif_put(struct snd_kcontrol *kcontrol,
+			    struct snd_ctl_elem_value *uvalue)
+{
+	unsigned int ch_status;
+	mxc_spdif_control.ch_status[0] = uvalue->value.iec958.status[0];
+	mxc_spdif_control.ch_status[1] = uvalue->value.iec958.status[1];
+	mxc_spdif_control.ch_status[2] = uvalue->value.iec958.status[2];
+	mxc_spdif_control.ch_status[3] = uvalue->value.iec958.status[3];
+	ch_status =
+	    ((mxc_spdif_control.ch_status[2] << 16) | (mxc_spdif_control.
+						       ch_status[1] << 8) |
+	     mxc_spdif_control.ch_status[0]);
+	spdif_set_channel_status(ch_status, SPDIF_REG_STCSCH);
+	ch_status = mxc_spdif_control.ch_status[3];
+	spdif_set_channel_status(ch_status, SPDIF_REG_STCSCL);
+	return 0;
+}
+
+/*!
+ * This structure defines the spdif control interface
+ */
+struct snd_kcontrol_new snd_mxc_spdif_playback __devinitdata = {
+	.iface = SNDRV_CTL_ELEM_IFACE_MIXER,
+	.name = SNDRV_CTL_NAME_IEC958("", PLAYBACK, DEFAULT),
+	.info = mxc_pb_spdif_info,
+	.get = mxc_pb_spdif_get,
+	.put = mxc_pb_spdif_put,
+};
+
+/*!
+  * This function the soundcard structure.
+  *
+  * @param	mxc_spdif	pointer to the sound card structure.
+  *
+  * @return              0 on success, -1 otherwise.
+  */
+static int snd_card_mxc_spdif_pcm(struct mxc_spdif_device *mxc_spdif)
+{
+	struct snd_pcm *pcm;
+	int err;
+	err = snd_pcm_new(mxc_spdif->card, MXC_SPDIF_NAME, 0,
+			  mxc_spdif->mxc_spdif_tx,
+			  mxc_spdif->mxc_spdif_rx, &pcm);
+	if (err < 0)
+		return err;
+
+	snd_pcm_lib_preallocate_pages_for_all(pcm,
+					      SNDRV_DMA_TYPE_CONTINUOUS,
+					      snd_dma_continuous_data
+					      (GFP_KERNEL),
+					      SPDIF_MAX_BUF_SIZE * 2,
+					      SPDIF_MAX_BUF_SIZE * 2);
+	if (mxc_spdif->mxc_spdif_tx)
+		snd_pcm_set_ops(pcm,
+				SNDRV_PCM_STREAM_PLAYBACK,
+				&snd_card_mxc_spdif_playback_ops);
+	if (mxc_spdif->mxc_spdif_rx)
+		snd_pcm_set_ops(pcm,
+				SNDRV_PCM_STREAM_CAPTURE,
+				&snd_card_mxc_spdif_capture_ops);
+	pcm->private_data = mxc_spdif;
+	pcm->info_flags = 0;
+	strncpy(pcm->name, MXC_SPDIF_NAME, sizeof(pcm->name));
+	mxc_spdif->pcm = pcm;
+	mxc_init_spdif_device(mxc_spdif);
+	return 0;
+}
+
+/*!
+  * This function initializes the driver in terms of memory of the soundcard
+  * and some basic HW clock settings.
+  *
+  * @param	pdev	Pointer to the platform device
+  * @return              0 on success, -1 otherwise.
+  */
+static int mxc_alsa_spdif_probe(struct platform_device
+				*pdev)
+{
+	int err;
+	struct snd_card *card;
+	struct mxc_spdif_device *chip;
+	struct resource *res;
+	struct mxc_spdif_platform_data *spdif_platform_data;
+
+	res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
+	if (!res)
+		return -ENOENT;
+
+	/* register the soundcard */
+	card = snd_card_new(SNDRV_DEFAULT_IDX1, SNDRV_DEFAULT_STR1, THIS_MODULE,
+			    sizeof(struct mxc_spdif_device));
+	if (card == NULL)
+		return -ENOMEM;
+	chip = card->private_data;
+	chip->card = card;
+	card->dev = &pdev->dev;
+	chip->reg_base = ioremap(res->start, res->end - res->start + 1);
+	spdif_base_addr = (unsigned long)chip->reg_base;
+	spdif_platform_data =
+	    (struct mxc_spdif_platform_data *)pdev->dev.platform_data;
+	chip->mxc_spdif_tx = spdif_platform_data->spdif_tx;
+	chip->mxc_spdif_rx = spdif_platform_data->spdif_rx;
+	chip->spdif_txclk_44100 = spdif_platform_data->spdif_clk_44100;
+	chip->spdif_txclk_48000 = spdif_platform_data->spdif_clk_48000;
+	err = snd_card_mxc_spdif_pcm(chip);
+	if (err < 0)
+		goto nodev;
+	err = snd_ctl_add(card,
+			  snd_ctl_new1(&snd_mxc_spdif_playback,
+				       &mxc_spdif_control));
+	if (err < 0)
+		return err;
+
+	if (chip->mxc_spdif_tx)
+		spin_lock_init(&chip->s[SNDRV_PCM_STREAM_PLAYBACK].dma_lock);
+	if (chip->mxc_spdif_rx)
+		spin_lock_init(&chip->s[SNDRV_PCM_STREAM_CAPTURE].dma_lock);
+	strcpy(card->driver, MXC_SPDIF_NAME);
+	strcpy(card->shortname, "MXC SPDIF TX/RX");
+	sprintf(card->longname, "MXC Freescale with SPDIF");
+	err = snd_card_register(card);
+	if (err == 0) {
+		pr_debug(KERN_INFO "MXC spdif support initialized\n");
+		platform_set_drvdata(pdev, card);
+		return 0;
+	}
+
+      nodev:
+	snd_card_free(card);
+	return err;
+}
+
+/*!
+  * This function releases the sound card and unmap the io address
+  *
+  * @param      pdev    Pointer to the platform device
+  * @return              0 on success, -1 otherwise.
+  */
+
+static int mxc_alsa_spdif_remove(struct platform_device *pdev)
+{
+	struct mxc_spdif_device *chip;
+	struct snd_card *card;
+	card = platform_get_drvdata(pdev);
+	chip = card->private_data;
+	iounmap(chip->reg_base);
+	snd_card_free(card);
+	platform_set_drvdata(pdev, NULL);
+	return 0;
+}
+
+#ifdef CONFIG_PM
+/*!
+  * This function suspends all active streams.
+  *
+  * TBD
+  *
+  * @param	card	pointer to the sound card structure.
+  * @param	state	requested state
+  *
+  * @return              0 on success, -1 otherwise.
+  */
+static int snd_mxc_spdif_suspend(struct platform_device *pdev,
+				 pm_message_t state)
+{
+	return 0;
+}
+
+/*!
+  * This function resumes all suspended streams.
+  *
+  * TBD
+  *
+  * @param	card	pointer to the sound card structure.
+  * @param	state	requested state
+  *
+  * @return              0 on success, -1 otherwise.
+  */
+static int snd_mxc_spdif_resume(struct platform_device *pdev)
+{
+	return 0;
+}
+#endif
+
+static struct platform_driver mxc_alsa_spdif_driver = {
+	.probe = mxc_alsa_spdif_probe,
+	.remove = mxc_alsa_spdif_remove,
+#ifdef CONFIG_PM
+	.suspend = mxc_alsa_spdif_suspend,
+	.resume = mxc_alsa_spdif_resume,
+#endif
+	.driver = {
+		   .name = "mxc_alsa_spdif",
+		   },
+};
+
+/*!
+  * This function registers the sound driver structure.
+  *
+  */
+static int __init mxc_alsa_spdif_init(void)
+{
+	return platform_driver_register(&mxc_alsa_spdif_driver);
+}
+
+/*!
+  * This function frees the sound driver structure.
+  *
+  */
+static void __exit mxc_alsa_spdif_exit(void)
+{
+	platform_driver_unregister(&mxc_alsa_spdif_driver);
+}
+
+module_init(mxc_alsa_spdif_init);
+module_exit(mxc_alsa_spdif_exit);
+MODULE_AUTHOR("FREESCALE SEMICONDUCTOR");
+MODULE_LICENSE("GPL");
+MODULE_DESCRIPTION("MXC ALSA driver for SPDIF");