Subject: [PATCH] ASoC: Add support for BCM2708

From: [email-masked] (Florian Meier)
Date: Wed, 22 May 2013 16:10:20 +0200

This driver adds support for digital audio (I2S)
for the BCM2708 SoC that is used by the
Raspberry Pi. External audio codecs can be
connected to the Raspberry Pi via P5 header.

It relies on cyclic DMA engine support for BCM2708
that is not included in this patch.

The currently supported audio codecs are
TLV320AIC23 and WM8731.

Signed-off-by: Florian Meier <[email-masked]>
---

A Raspberry Pi kernel featuring this driver can be found at
https://github.com/koalo/linux rpi-3.8.y-asocdev

You can find more information about how to use it at
http://blog.koalo.de/2013/05/i2s-support-for-raspberry-pi.html

 sound/soc/Kconfig               |    1 +
 sound/soc/Makefile              |    1 +
 sound/soc/bcm2708/Kconfig       |   29 ++
 sound/soc/bcm2708/Makefile      |   12 +
 sound/soc/bcm2708/bcm2708-i2s.c |  964 +++++++++++++++++++++++++++++++++++++++
 sound/soc/bcm2708/bcm2708-pcm.c |  303 ++++++++++++
 sound/soc/bcm2708/bcm2708-pcm.h |   40 ++
 sound/soc/bcm2708/rpi-mbed.c    |  113 +++++
 sound/soc/bcm2708/rpi-proto.c   |  131 ++++++
 9 files changed, 1594 insertions(+)
 create mode 100644 sound/soc/bcm2708/Kconfig
 create mode 100644 sound/soc/bcm2708/Makefile
 create mode 100644 sound/soc/bcm2708/bcm2708-i2s.c
 create mode 100644 sound/soc/bcm2708/bcm2708-pcm.c
 create mode 100644 sound/soc/bcm2708/bcm2708-pcm.h
 create mode 100644 sound/soc/bcm2708/rpi-mbed.c
 create mode 100644 sound/soc/bcm2708/rpi-proto.c

diff --git a/sound/soc/Kconfig b/sound/soc/Kconfig
index 9e675c7..d3852f8 100644
--- a/sound/soc/Kconfig
+++ b/sound/soc/Kconfig
@@ -36,6 +36,7 @@ config SND_SOC_GENERIC_DMAENGINE_PCM
 # All the supported SoCs
 source "sound/soc/atmel/Kconfig"
 source "sound/soc/au1x/Kconfig"
+source "sound/soc/bcm2708/Kconfig"
 source "sound/soc/blackfin/Kconfig"
 source "sound/soc/cirrus/Kconfig"
 source "sound/soc/davinci/Kconfig"
diff --git a/sound/soc/Makefile b/sound/soc/Makefile
index 197b6ae..eef1a7b 100644
--- a/sound/soc/Makefile
+++ b/sound/soc/Makefile
@@ -14,6 +14,7 @@ obj-$(CONFIG_SND_SOC)	+= codecs/
 obj-$(CONFIG_SND_SOC)	+= generic/
 obj-$(CONFIG_SND_SOC)	+= atmel/
 obj-$(CONFIG_SND_SOC)	+= au1x/
+obj-$(CONFIG_SND_SOC)	+= bcm2708/
 obj-$(CONFIG_SND_SOC)	+= blackfin/
 obj-$(CONFIG_SND_SOC)	+= cirrus/
 obj-$(CONFIG_SND_SOC)	+= davinci/
diff --git a/sound/soc/bcm2708/Kconfig b/sound/soc/bcm2708/Kconfig
new file mode 100644
index 0000000..f47c2c0
--- /dev/null
+++ b/sound/soc/bcm2708/Kconfig
@@ -0,0 +1,29 @@
+config SND_BCM2708_SOC_I2S
+	tristate
+
+config SND_BCM2708_SOC
+	tristate "SoC Audio support for the Broadcom BCM2708 I2S module"
+	depends on MACH_BCM2708
+	select SND_SOC_DMAENGINE_PCM
+	select DMA_BCM2708
+	select SND_SOC_GENERIC_DMAENGINE_PCM
+	help
+	  Say Y or M if you want to add support for codecs attached to
+	  the BCM2708 I2S interface. You will also need
+	  to select the audio interfaces to support below.
+
+config SND_BCM2708_SOC_RPI_CODEC_MBED
+	tristate "Support for AudioCODEC for mbed (TLV320AIC32B)"
+	depends on SND_BCM2708_SOC
+	select SND_BCM2708_SOC_I2S
+	select SND_SOC_TLV320AIC3X
+	help
+	  Say Y if you want to add support for AudioCODEC for mbed (TLV320AIC32B)
+
+config SND_BCM2708_SOC_RPI_CODEC_PROTO
+	tristate "Support for Audio Codec Board - PROTO (WM8731)"
+	depends on SND_BCM2708_SOC
+	select SND_BCM2708_SOC_I2S
+	select SND_SOC_WM8731
+	help
+	  Say Y if you want to add support for Audio Codec Board - PROTO (WM8731)
diff --git a/sound/soc/bcm2708/Makefile b/sound/soc/bcm2708/Makefile
new file mode 100644
index 0000000..284d76d
--- /dev/null
+++ b/sound/soc/bcm2708/Makefile
@@ -0,0 +1,12 @@
+# BCM2708 Platform Support
+snd-soc-bcm2708-objs := bcm2708-pcm.o
+snd-soc-bcm2708-i2s-objs := bcm2708-i2s.o
+snd-soc-rpi-mbed-objs := rpi-mbed.o
+snd-soc-rpi-proto-objs := rpi-proto.o
+
+obj-$(CONFIG_SND_BCM2708_SOC) += snd-soc-bcm2708.o
+obj-$(CONFIG_SND_BCM2708_SOC_I2S) += snd-soc-bcm2708-i2s.o
+
+# BCM2708 Machine Support
+obj-$(CONFIG_SND_BCM2708_SOC_RPI_CODEC_MBED) += snd-soc-rpi-mbed.o
+obj-$(CONFIG_SND_BCM2708_SOC_RPI_CODEC_PROTO) += snd-soc-rpi-proto.o
diff --git a/sound/soc/bcm2708/bcm2708-i2s.c b/sound/soc/bcm2708/bcm2708-i2s.c
new file mode 100644
index 0000000..a8e995f
--- /dev/null
+++ b/sound/soc/bcm2708/bcm2708-i2s.c
@@ -0,0 +1,964 @@
+/*
+ * ALSA SoC I2S Audio Layer for Broadcom BCM2708 SoC
+ *
+ * Author:	Florian Meier, <[email-masked]>
+ *		Copyright 2013
+ *
+ * based on
+ *	Raspberry Pi PCM I2S ALSA Driver
+ *	Copyright (c) by Phil Poole 2013
+ *
+ *	ALSA SoC I2S (McBSP) Audio Layer for TI DAVINCI processor
+ *      Vladimir Barinov, <[email-masked]>
+ *	Copyright (C) 2007 MontaVista Software, Inc., <[email-masked]>
+ *
+ *	OMAP ALSA SoC DAI driver using McBSP port
+ *	Copyright (C) 2008 Nokia Corporation
+ *	Contact: Jarkko Nikula <[email-masked]>
+ *		 Peter Ujfalusi <[email-masked]>
+ *
+ *	Freescale SSI ALSA SoC Digital Audio Interface (DAI) driver
+ *	Author: Timur Tabi <[email-masked]>
+ *	Copyright 2007-2010 Freescale Semiconductor, Inc.
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation; either version 2 of the License, or
+ * (at your option) any later version.
+ *
+ * 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.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program; if not, write to the Free Software
+ * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA
+ */
+
+#include <linux/init.h>
+#include <linux/module.h>
+#include <linux/device.h>
+#include <linux/slab.h>
+#include <linux/delay.h>
+#include <linux/io.h>
+#include <linux/clk.h>
+
+#include <sound/core.h>
+#include <sound/pcm.h>
+#include <sound/pcm_params.h>
+#include <sound/initval.h>
+#include <sound/soc.h>
+
+#include "bcm2708-pcm.h"
+
+/* Clock registers */
+#define BCM2708_CLK_PCMCTL_REG  0x00
+#define BCM2708_CLK_PCMDIV_REG  0x04
+
+/* Clock register settings */
+#define BCM2708_CLK_PASSWD	(0x5a000000)
+#define BCM2708_CLK_MASH(v)	((v) << 9)
+#define BCM2708_CLK_FLIP	(1 << 8)
+#define BCM2708_CLK_BUSY	(1 << 7)
+#define BCM2708_CLK_KILL	(1 << 5)
+#define BCM2708_CLK_ENAB	(1 << 4)
+#define BCM2708_CLK_SRC(v)	(v)
+
+#define BCM2708_CLK_DIVI(v)	((v) << 12)
+#define BCM2708_CLK_DIVF(v)	(v)
+
+enum {
+	BCM2708_CLK_MASH_0 = 0,
+	BCM2708_CLK_MASH_1,
+	BCM2708_CLK_MASH_2,
+	BCM2708_CLK_MASH_3,
+};
+
+enum {
+	BCM2708_CLK_SRC_GND = 0,
+	BCM2708_CLK_SRC_OSC,
+	BCM2708_CLK_SRC_DBG0,
+	BCM2708_CLK_SRC_DBG1,
+	BCM2708_CLK_SRC_PLLA,
+	BCM2708_CLK_SRC_PLLC,
+	BCM2708_CLK_SRC_PLLD,
+	BCM2708_CLK_SRC_HDMI,
+};
+
+/* Most clocks are not useable (freq = 0) */
+static const unsigned int bcm2708_clk_freq[BCM2708_CLK_SRC_HDMI+1] = {
+	[BCM2708_CLK_SRC_GND]		= 0,
+	[BCM2708_CLK_SRC_OSC]		= 19200000,
+	[BCM2708_CLK_SRC_DBG0]		= 0,
+	[BCM2708_CLK_SRC_DBG1]		= 0,
+	[BCM2708_CLK_SRC_PLLA]		= 0,
+	[BCM2708_CLK_SRC_PLLC]		= 0,
+	[BCM2708_CLK_SRC_PLLD]		= 500000000,
+	[BCM2708_CLK_SRC_HDMI]		= 0,
+};
+
+
+/* I2S registers */
+#define BCM2708_I2S_CS_A_REG		0x00
+#define BCM2708_I2S_FIFO_A_REG		0x04
+#define BCM2708_I2S_MODE_A_REG		0x08
+#define BCM2708_I2S_RXC_A_REG		0x0c
+#define BCM2708_I2S_TXC_A_REG		0x10
+#define BCM2708_I2S_DREQ_A_REG		0x14
+#define BCM2708_I2S_INTEN_A_REG		0x18
+#define BCM2708_I2S_INTSTC_A_REG	0x1c
+#define BCM2708_I2S_GRAY_REG		0x20
+
+/* I2S register settings */
+#define BCM2708_I2S_STBY		(1 << 25)
+#define BCM2708_I2S_SYNC		(1 << 24)
+#define BCM2708_I2S_RXSEX		(1 << 23)
+#define BCM2708_I2S_RXF			(1 << 22)
+#define BCM2708_I2S_TXE			(1 << 21)
+#define BCM2708_I2S_RXD			(1 << 20)
+#define BCM2708_I2S_TXD			(1 << 19)
+#define BCM2708_I2S_RXR			(1 << 18)
+#define BCM2708_I2S_TXW			(1 << 17)
+#define BCM2708_I2S_CS_RXERR		(1 << 16)
+#define BCM2708_I2S_CS_TXERR		(1 << 15)
+#define BCM2708_I2S_RXSYNC		(1 << 14)
+#define BCM2708_I2S_TXSYNC		(1 << 13)
+#define BCM2708_I2S_DMAEN		(1 << 9)
+#define BCM2708_I2S_RXTHR(v)		((v) << 7)
+#define BCM2708_I2S_TXTHR(v)		((v) << 5)
+#define BCM2708_I2S_RXCLR		(1 << 4)
+#define BCM2708_I2S_TXCLR		(1 << 3)
+#define BCM2708_I2S_TXON		(1 << 2)
+#define BCM2708_I2S_RXON		(1 << 1)
+#define BCM2708_I2S_EN			(1)
+
+#define BCM2708_I2S_CLKDIS		(1 << 28)
+#define BCM2708_I2S_PDMN		(1 << 27)
+#define BCM2708_I2S_PDME		(1 << 26)
+#define BCM2708_I2S_FRXP		(1 << 25)
+#define BCM2708_I2S_FTXP		(1 << 24)
+#define BCM2708_I2S_CLKM		(1 << 23)
+#define BCM2708_I2S_CLKI		(1 << 22)
+#define BCM2708_I2S_FSM			(1 << 21)
+#define BCM2708_I2S_FSI			(1 << 20)
+#define BCM2708_I2S_FLEN(v)		((v) << 10)
+#define BCM2708_I2S_FSLEN(v)		(v)
+
+#define BCM2708_I2S_CHWEX		(1 << 15)
+#define BCM2708_I2S_CHEN		(1 << 14)
+#define BCM2708_I2S_CHPOS(v)		((v) << 4)
+#define BCM2708_I2S_CHWID(v)		(v)
+#define BCM2708_I2S_CH1(v)		((v) << 16)
+#define BCM2708_I2S_CH2(v)		(v)
+
+#define BCM2708_I2S_TX_PANIC(v)		((v) << 24)
+#define BCM2708_I2S_RX_PANIC(v)		((v) << 16)
+#define BCM2708_I2S_TX(v)		((v) << 8)
+#define BCM2708_I2S_RX(v)		(v)
+
+#define BCM2708_I2S_INT_RXERR		(1 << 3)
+#define BCM2708_I2S_INT_TXERR		(1 << 2)
+#define BCM2708_I2S_INT_RXR		(1 << 1)
+#define BCM2708_I2S_INT_TXW		(1 << 0)
+
+/* I2S DMA interface */
+#define BCM2708_I2S_FIFO_PHYSICAL_ADDR	0x7E203004
+#define BCM2708_DMA_DREQ_PCM_TX		2
+#define BCM2708_DMA_DREQ_PCM_RX		3
+
+/* General device struct */
+struct bcm2708_i2s_dev {
+	struct device				*dev;
+	struct bcm2708_pcm_dma_data		dma_params[2];
+	void __iomem				*i2s_base;
+	void __iomem				*clk_base;
+	unsigned int				fmt;
+	struct snd_pcm_substream		*first_stream;
+	struct snd_pcm_substream		*second_stream;
+};
+
+static inline void bcm2708_i2s_write_reg(struct bcm2708_i2s_dev *dev,
+					   int reg, u32 val)
+{
+	dev_dbg(dev->dev, "I2S write to register %p = %x\n",
+			dev->clk_base + reg, val);
+	__raw_writel(val, dev->i2s_base + reg);
+}
+
+static inline u32 bcm2708_i2s_read_reg(struct bcm2708_i2s_dev *dev, int reg)
+{
+	return __raw_readl(dev->i2s_base + reg);
+}
+
+static inline void bcm2708_i2s_set_bits(struct bcm2708_i2s_dev *dev,
+					   int reg, u32 val)
+{
+	u32 oldval = __raw_readl(dev->i2s_base + reg);
+	bcm2708_i2s_write_reg(dev, reg, oldval | val);
+}
+
+static inline void bcm2708_i2s_clear_bits(struct bcm2708_i2s_dev *dev,
+					   int reg, u32 val)
+{
+	u32 oldval = __raw_readl(dev->i2s_base + reg);
+	bcm2708_i2s_write_reg(dev, reg, oldval & ~val);
+}
+
+static inline void bcm2708_clk_write_reg(struct bcm2708_i2s_dev *dev,
+					   int reg, u32 val)
+{
+	dev_dbg(dev->dev, "PCM clk write to register %p = %x\n",
+			dev->clk_base + reg, val);
+	__raw_writel(val, dev->clk_base + reg);
+}
+
+static inline u32 bcm2708_clk_read_reg(struct bcm2708_i2s_dev *dev, int reg)
+{
+	return __raw_readl(dev->clk_base + reg);
+}
+
+static void bcm2708_i2s_start_clock(struct bcm2708_i2s_dev *dev)
+{
+	/*
+	 * Start the clock if in master mode.
+	 */
+	unsigned int master = dev->fmt & SND_SOC_DAIFMT_MASTER_MASK;
+	if (master == SND_SOC_DAIFMT_CBS_CFS
+			|| master == SND_SOC_DAIFMT_CBS_CFM) {
+		unsigned int clkreg = bcm2708_clk_read_reg(dev,
+				BCM2708_CLK_PCMCTL_REG);
+		bcm2708_clk_write_reg(dev, BCM2708_CLK_PCMCTL_REG,
+				BCM2708_CLK_PASSWD | clkreg | BCM2708_CLK_ENAB);
+	}
+}
+
+static void bcm2708_i2s_stop_clock(struct bcm2708_i2s_dev *dev)
+{
+	int timeout = 1000;
+
+	/* stop clock */
+	unsigned int clkreg = bcm2708_clk_read_reg(dev, BCM2708_CLK_PCMCTL_REG);
+	bcm2708_clk_write_reg(dev, BCM2708_CLK_PCMCTL_REG, ~(BCM2708_CLK_ENAB)
+		& (BCM2708_CLK_PASSWD | clkreg));
+
+	/* wait for the BUSY flag going down */
+	while ((bcm2708_clk_read_reg(dev, BCM2708_CLK_PCMCTL_REG)
+				& BCM2708_CLK_BUSY)
+			&& timeout > 0) {
+		timeout--;
+	}
+
+	if (timeout <= 0) {
+		/* KILL the clock */
+		dev_err(dev->dev, "I2S clock didn't stop. Kill the clock!\n");
+		bcm2708_clk_write_reg(dev, BCM2708_CLK_PCMCTL_REG,
+				BCM2708_CLK_KILL | BCM2708_CLK_PASSWD
+				| clkreg);
+	}
+}
+
+static void bcm2708_i2s_clear_fifos(struct bcm2708_i2s_dev *dev)
+{
+	int timeout = 1000;
+	unsigned int syncval;
+
+	/* Backup the current state */
+	unsigned int i2s_active_state = bcm2708_i2s_read_reg(dev,
+			BCM2708_I2S_CS_A_REG)
+			& (BCM2708_I2S_RXON | BCM2708_I2S_TXON);
+
+	unsigned int clk_active_state = bcm2708_clk_read_reg(dev,
+			BCM2708_CLK_PCMCTL_REG) & BCM2708_CLK_ENAB;
+
+	/* Start clock if not running */
+	if (!clk_active_state) {
+		unsigned int clkreg = bcm2708_clk_read_reg(dev,
+				BCM2708_CLK_PCMCTL_REG);
+		bcm2708_clk_write_reg(dev, BCM2708_CLK_PCMCTL_REG,
+				BCM2708_CLK_PASSWD | clkreg | BCM2708_CLK_ENAB);
+	}
+
+	/* Stop I2S module */
+	bcm2708_i2s_clear_bits(dev, BCM2708_I2S_CS_A_REG, BCM2708_I2S_RXON
+							| BCM2708_I2S_TXON);
+
+	/*
+	 * Clear the FIFOs
+	 * Requires at least 2 PCM clock cycles to take effect
+	 */
+	bcm2708_i2s_set_bits(dev, BCM2708_I2S_CS_A_REG, BCM2708_I2S_RXCLR
+							| BCM2708_I2S_TXCLR);
+
+	/* Wait for 2 PCM clock cycles */
+
+	/*
+	 * Toggle the SYNC flag - after 2 PCM clock cycles it can be read back
+	 * FIXME: This does not seem to work for slave mode!
+	 */
+	syncval = bcm2708_i2s_read_reg(dev, BCM2708_I2S_CS_A_REG)
+					& BCM2708_I2S_SYNC;
+	if (syncval)
+		bcm2708_i2s_clear_bits(dev, BCM2708_I2S_CS_A_REG,
+					BCM2708_I2S_SYNC);
+	else
+		bcm2708_i2s_set_bits(dev, BCM2708_I2S_CS_A_REG,
+					BCM2708_I2S_SYNC);
+
+	/* Wait for the SYNC flag changing it's state */
+	while (((bcm2708_i2s_read_reg(dev, BCM2708_I2S_CS_A_REG)
+					& BCM2708_I2S_SYNC) == syncval)
+			&& timeout > 0) {
+		timeout--;
+	}
+
+	if (timeout <= 0)
+		dev_err(dev->dev, "I2S SYNC error!\n");
+
+	/* Stop clock if it was not running before */
+	if (!clk_active_state)
+		bcm2708_i2s_stop_clock(dev);
+
+	/* Restore I2S state */
+	bcm2708_i2s_set_bits(dev, BCM2708_I2S_CS_A_REG, i2s_active_state);
+}
+
+static void bcm2708_i2s_start(struct bcm2708_i2s_dev *dev,
+		struct snd_pcm_substream *substream)
+{
+	bcm2708_i2s_start_clock(dev);
+
+	/*
+	 * Enable the stream.
+	 */
+	if (substream->stream == SNDRV_PCM_STREAM_CAPTURE) {
+		bcm2708_i2s_set_bits(dev, BCM2708_I2S_CS_A_REG,
+				BCM2708_I2S_RXON);
+	} else {
+		bcm2708_i2s_set_bits(dev, BCM2708_I2S_CS_A_REG,
+				BCM2708_I2S_TXON);
+	}
+}
+
+static void bcm2708_i2s_stop(struct bcm2708_i2s_dev *dev,
+		struct snd_pcm_substream *substream)
+{
+	unsigned int still_running;
+
+	if (substream->stream == SNDRV_PCM_STREAM_CAPTURE) {
+		bcm2708_i2s_clear_bits(dev, BCM2708_I2S_CS_A_REG,
+				BCM2708_I2S_RXON);
+	} else {
+		bcm2708_i2s_clear_bits(dev, BCM2708_I2S_CS_A_REG,
+				BCM2708_I2S_TXON);
+	}
+
+	still_running = bcm2708_i2s_read_reg(dev, BCM2708_I2S_CS_A_REG)
+				& (BCM2708_I2S_TXON | BCM2708_I2S_RXON);
+
+	/* Stop also the clock when not SND_SOC_DAIFMT_CONT */
+	if (!still_running && !(dev->fmt & SND_SOC_DAIFMT_CONT))
+		bcm2708_i2s_stop_clock(dev);
+
+}
+
+static int bcm2708_i2s_set_dai_fmt(struct snd_soc_dai *dai,
+				      unsigned int fmt)
+{
+	struct bcm2708_i2s_dev *dev = snd_soc_dai_get_drvdata(dai);
+	dev->fmt = fmt;
+	return 0;
+}
+
+static bool bcm2708_i2s_check_other_stream(struct bcm2708_i2s_dev *dev,
+					struct snd_pcm_substream *substream,
+					struct snd_pcm_substream *other_stream,
+					struct snd_pcm_hw_params *params)
+{
+	if (other_stream->runtime->format &&
+		(other_stream->runtime->format != params_format(params))) {
+		dev_err(dev->dev,
+			"Sample formats of streams are different. %i (%s) != %i (%s) Initialization failed!\n",
+			other_stream->runtime->format,
+			(other_stream->stream ==
+			 SNDRV_PCM_STREAM_PLAYBACK ?
+			 "playback" : "capture"),
+			params_format(params),
+			(substream->stream ==
+			 SNDRV_PCM_STREAM_PLAYBACK ?
+			 "playback" : "capture"));
+		return false;
+	}
+
+	if (other_stream->runtime->rate &&
+			(other_stream->runtime->rate != params_rate(params))) {
+		dev_err(dev->dev,
+			"Sampling rates of streams are different. %i (%s) != %i (%s) Initialization failed!\n",
+			other_stream->runtime->rate,
+			(other_stream->stream ==
+			 SNDRV_PCM_STREAM_PLAYBACK ?
+			 "playback" : "capture"),
+			params_rate(params),
+			(substream->stream ==
+			 SNDRV_PCM_STREAM_PLAYBACK ?
+			 "playback" : "capture"));
+		return false;
+	}
+
+	return true;
+}
+
+static int bcm2708_i2s_hw_params(struct snd_pcm_substream *substream,
+				 struct snd_pcm_hw_params *params,
+				 struct snd_soc_dai *dai)
+{
+	struct bcm2708_i2s_dev *dev = snd_soc_dai_get_drvdata(dai);
+
+	unsigned int sampling_rate = params_rate(params);
+	unsigned int data_length, data_delay, half_frame;
+	unsigned int ch1pos, ch2pos, mode, format;
+	unsigned int mash = BCM2708_CLK_MASH_1;
+	unsigned int divi, divf, target_frequency;
+	int clk_src = -1;
+	unsigned int master = dev->fmt & SND_SOC_DAIFMT_MASTER_MASK;
+	unsigned int bit_master =	(master == SND_SOC_DAIFMT_CBS_CFS
+					|| master == SND_SOC_DAIFMT_CBS_CFM);
+
+	unsigned int frame_master =	(master == SND_SOC_DAIFMT_CBS_CFS
+					|| master == SND_SOC_DAIFMT_CBM_CFS);
+
+	/* Ensure, that both streams have the same settings */
+	struct snd_pcm_substream *other_stream = dev->first_stream;
+	if (other_stream == substream)
+		other_stream = dev->second_stream;
+
+	if (other_stream != NULL
+		&& !bcm2708_i2s_check_other_stream(dev,
+			substream, other_stream, params))
+		return -EINVAL;
+
+	/*
+	 * If a stream is already enabled,
+	 * the registers are already set properly.
+	 */
+	if (bcm2708_i2s_read_reg(dev, BCM2708_I2S_CS_A_REG)
+			& (BCM2708_I2S_TXON | BCM2708_I2S_RXON))
+		return 0;
+
+	/*
+	 * Adjust the data length according to the format.
+	 * We prefill the half frame length with an integer
+	 * divider of 2400 as explained at the clock settings.
+	 * Maybe it is overwritten there, if the Integer mode
+	 * does not apply.
+	 */
+	switch (params_format(params)) {
+	case SNDRV_PCM_FORMAT_S16_LE:
+		data_length = 16;
+		half_frame = 20;
+		break;
+	case SNDRV_PCM_FORMAT_S32_LE:
+		data_length = 32;
+		half_frame = 40;
+		break;
+	default:
+		return -EINVAL;
+	}
+
+	/*
+	 * Clock Settings
+	 *
+	 * The target frequency of the bit clock is
+	 *	sampling rate * frame length
+	 *
+	 * Integer mode:
+	 * Sampling rates that are multiples of 8000 kHz
+	 * can be driven by the oscillator of 19.2 MHz
+	 * with an integer divider as long as the frame length
+	 * is an integer divider of 19200000/8000=2400 as set up above.
+	 * This is no longer possible if the sampling rate
+	 * is too high (e.g. 192 kHz), because the oscillator is too slow.
+	 *
+	 * MASH mode:
+	 * For all other sampling rates, it is not possible to
+	 * have an integer divider. Approximate the clock
+	 * with the MASH module that induces a slight frequency
+	 * variance. To minimize that it is best to have the fastest
+	 * clock here. That is PLLD with 500 MHz.
+	 */
+	target_frequency = sampling_rate*half_frame*2;
+	clk_src = BCM2708_CLK_SRC_OSC;
+	mash = BCM2708_CLK_MASH_0;
+
+	if (bcm2708_clk_freq[clk_src] % target_frequency == 0
+			&& bit_master && frame_master) {
+		divi = bcm2708_clk_freq[clk_src]/target_frequency;
+		divf = 0;
+	} else {
+		uint64_t dividend;
+
+		/*
+		 * Overwrite half frame length, because the
+		 * above trick is not needed.
+		 * This is fixed, because a bit clock of 64*fs
+		 * seems to be what most codecs want.
+		 * Is it necessary to have this dynamic?
+		 */
+		half_frame = 32;
+		target_frequency = sampling_rate*half_frame*2;
+
+		clk_src = BCM2708_CLK_SRC_PLLD;
+		mash = BCM2708_CLK_MASH_1;
+
+		dividend = bcm2708_clk_freq[clk_src];
+		dividend *= 1024;
+		do_div(dividend, target_frequency);
+		divi = dividend / 1024;
+		divf = dividend % 1024;
+	}
+
+	/* Set clock divider */
+	bcm2708_clk_write_reg(dev, BCM2708_CLK_PCMDIV_REG, BCM2708_CLK_PASSWD
+			| BCM2708_CLK_DIVI(divi)
+			| BCM2708_CLK_DIVF(divf));
+
+	/* Setup clock, but don't start it yet */
+	bcm2708_clk_write_reg(dev, BCM2708_CLK_PCMCTL_REG, BCM2708_CLK_PASSWD
+			| BCM2708_CLK_MASH(mash)
+			| BCM2708_CLK_SRC(clk_src));
+
+
+	/* Setup the frame format */
+	format = BCM2708_I2S_CHEN;
+
+	if (data_length > 24)
+		format |= BCM2708_I2S_CHWEX;
+
+	format |= BCM2708_I2S_CHWID((data_length-8)&0xf);
+
+	switch (dev->fmt & SND_SOC_DAIFMT_FORMAT_MASK) {
+	case SND_SOC_DAIFMT_I2S:
+		data_delay = 1;
+		break;
+	default:
+		/* TODO
+		 * Others are possible but are not implemented at the moment.
+		 */
+		dev_err(dev->dev, "%s:bad format\n", __func__);
+		return -EINVAL;
+	}
+
+	ch1pos = data_delay;
+	ch2pos = half_frame+data_delay;
+
+	switch (params_channels(params)) {
+	case 2:
+		format = BCM2708_I2S_CH1(format) | BCM2708_I2S_CH2(format);
+		format |= BCM2708_I2S_CH1(BCM2708_I2S_CHPOS(ch1pos));
+		format |= BCM2708_I2S_CH2(BCM2708_I2S_CHPOS(ch2pos));
+		break;
+	default:
+		return -EINVAL;
+	}
+
+	/*
+	 * Set format for both streams.
+	 * We cannot set another frame length
+	 * (and therefore word length) anyway,
+	 * so the format will be the same.
+	 */
+	bcm2708_i2s_write_reg(dev, BCM2708_I2S_RXC_A_REG, format);
+	bcm2708_i2s_write_reg(dev, BCM2708_I2S_TXC_A_REG, format);
+
+
+	/* Setup the I2S mode */
+	mode = 0;
+
+	if (data_length <= 16) {
+		/*
+		 * Use frame packed mode (2 channels per 32 bit word)
+		 * We cannot set another frame length in the second stream
+		 * (and therefore word length) anyway,
+		 * so the format will be the same.
+		 */
+		mode |= BCM2708_I2S_FTXP | BCM2708_I2S_FRXP;
+	}
+
+	mode |= BCM2708_I2S_FLEN(half_frame*2-1);
+	mode |= BCM2708_I2S_FSLEN(half_frame);
+
+	/* master or slave? */
+	switch (dev->fmt & SND_SOC_DAIFMT_MASTER_MASK) {
+	case SND_SOC_DAIFMT_CBS_CFS:
+		/* cpu is master */
+		break;
+	case SND_SOC_DAIFMT_CBM_CFS:
+		/*
+		 * codec is bit clock master
+		 * cpu is frame master
+		 */
+		mode |= BCM2708_I2S_CLKM;
+		break;
+	case SND_SOC_DAIFMT_CBS_CFM:
+		/*
+		 * codec is frame master
+		 * cpu is bit clock master
+		 */
+		mode |= BCM2708_I2S_FSM;
+		break;
+	case SND_SOC_DAIFMT_CBM_CFM:
+		/* codec is master */
+		mode |= BCM2708_I2S_CLKM;
+		mode |= BCM2708_I2S_FSM;
+		break;
+	default:
+		dev_err(dev->dev, "%s:bad master\n", __func__);
+		return -EINVAL;
+	}
+
+	/*
+	 * Invert clocks?
+	 *
+	 * The BCM approach seems to be inverted to the classical I2S approach.
+	 */
+	switch (dev->fmt & SND_SOC_DAIFMT_INV_MASK) {
+	case SND_SOC_DAIFMT_NB_NF:
+		/* none - therefore, both for BCM */
+		mode |= BCM2708_I2S_CLKI;
+		mode |= BCM2708_I2S_FSI;
+		break;
+	case SND_SOC_DAIFMT_IB_IF:
+		/* both - therefore, none for BCM*/
+		break;
+	case SND_SOC_DAIFMT_NB_IF:
+		/*
+		 * invert only frame sync - therefore,
+		 * invert only bit clock for BCM
+		 */
+		mode |= BCM2708_I2S_CLKI;
+		break;
+	case SND_SOC_DAIFMT_IB_NF:
+		/*
+		 * invert only bit clock - therefore,
+		 * invert only frame sync for BCM
+		 */
+		mode |= BCM2708_I2S_FSI;
+		break;
+	default:
+		return -EINVAL;
+	}
+
+	bcm2708_i2s_write_reg(dev, BCM2708_I2S_MODE_A_REG, mode);
+
+
+	/* Setup the DMA parameters */
+	bcm2708_i2s_set_bits(dev, BCM2708_I2S_CS_A_REG, BCM2708_I2S_RXTHR(1)
+			| BCM2708_I2S_TXTHR(1)
+			| BCM2708_I2S_DMAEN);
+
+	bcm2708_i2s_write_reg(dev, BCM2708_I2S_DREQ_A_REG,
+			  BCM2708_I2S_TX_PANIC(0x10)
+			| BCM2708_I2S_RX_PANIC(0x30)
+			| BCM2708_I2S_TX(0x30)
+			| BCM2708_I2S_RX(0x20));
+
+	/* Clear FIFOs */
+	bcm2708_i2s_clear_fifos(dev);
+
+	return 0;
+}
+
+
+static int bcm2708_i2s_prepare(struct snd_pcm_substream *substream,
+		struct snd_soc_dai *dai)
+{
+	struct bcm2708_i2s_dev *dev = snd_soc_dai_get_drvdata(dai);
+	unsigned int cs_reg;
+
+	bcm2708_i2s_start_clock(dev);
+
+	/*
+	 * Clear both FIFOs if the one that should be started
+	 * is not empty at the moment. This should only happen
+	 * after overrun. Otherwise, hw_params would have cleared
+	 * the FIFO.
+	 */
+	cs_reg = bcm2708_i2s_read_reg(dev, BCM2708_I2S_CS_A_REG);
+
+	switch (substream->stream) {
+	case SNDRV_PCM_STREAM_PLAYBACK:
+		if (cs_reg & BCM2708_I2S_TXE)
+			break;
+	case SNDRV_PCM_STREAM_CAPTURE:
+		if (!(cs_reg & BCM2708_I2S_RXD))
+			break;
+
+		bcm2708_i2s_clear_fifos(dev);
+	}
+
+	return 0;
+}
+
+static int bcm2708_i2s_trigger(struct snd_pcm_substream *substream, int cmd,
+			       struct snd_soc_dai *dai)
+{
+	struct bcm2708_i2s_dev *dev = snd_soc_dai_get_drvdata(dai);
+
+	switch (cmd) {
+	case SNDRV_PCM_TRIGGER_START:
+	case SNDRV_PCM_TRIGGER_RESUME:
+	case SNDRV_PCM_TRIGGER_PAUSE_RELEASE:
+		bcm2708_i2s_start(dev, substream);
+		break;
+	case SNDRV_PCM_TRIGGER_STOP:
+	case SNDRV_PCM_TRIGGER_SUSPEND:
+	case SNDRV_PCM_TRIGGER_PAUSE_PUSH:
+		bcm2708_i2s_stop(dev, substream);
+		break;
+	default:
+		return -EINVAL;
+	}
+
+	return 0;
+}
+
+static int bcm2708_i2s_startup(struct snd_pcm_substream *substream,
+			       struct snd_soc_dai *dai)
+{
+	struct bcm2708_i2s_dev *dev = snd_soc_dai_get_drvdata(dai);
+
+	if (!dev->first_stream) {
+		dev->first_stream = substream;
+
+		/* should this still be running stop it */
+		bcm2708_i2s_stop_clock(dev);
+
+		/* enable PCM block */
+		bcm2708_i2s_set_bits(dev, BCM2708_I2S_CS_A_REG, BCM2708_I2S_EN);
+
+		/*
+		 * Disable STBY
+		 * Requires at least 4 PCM clock cycles to take effect
+		 */
+		bcm2708_i2s_set_bits(dev, BCM2708_I2S_CS_A_REG,
+				BCM2708_I2S_STBY);
+	} else {
+		struct snd_pcm_runtime *first_runtime =
+			dev->first_stream->runtime;
+
+		/*
+		 * This is the second stream open, so we need to impose
+		 * sample size and sampling rate constraints.
+		 * This is because frame length and clock cannot be specified
+		 * seperately.
+		 *
+		 * Note that this can cause a race condition if the
+		 * second stream is opened before the first stream is
+		 * fully initialized.  We provide some protection by
+		 * checking to make sure the first stream is
+		 * initialized, but it's not perfect.  ALSA sometimes
+		 * re-initializes the driver with a different sample
+		 * rate or size.  If the second stream is opened
+		 * before the first stream has received its final
+		 * parameters, then the second stream may be
+		 * constrained to the wrong sample rate or size.
+		 *
+		 * We will continue in case of failure and recheck the
+		 * constraint in hw_params.
+		 */
+		if (!first_runtime->format) {
+			dev_err(substream->pcm->card->dev,
+					"Set format in %s stream first! "
+					"Initialization may fail.\n",
+					substream->stream ==
+					SNDRV_PCM_STREAM_PLAYBACK
+					? "capture" : "playback");
+		} else {
+			snd_pcm_hw_constraint_minmax(substream->runtime,
+					SNDRV_PCM_HW_PARAM_FORMAT,
+					first_runtime->format,
+					first_runtime->format);
+		}
+
+		if (!first_runtime->rate) {
+			dev_err(substream->pcm->card->dev,
+					"Set sampling rate in %s stream first! "
+					"Initialization may fail!\n",
+					substream->stream ==
+					SNDRV_PCM_STREAM_PLAYBACK
+					? "capture" : "playback");
+		} else {
+			snd_pcm_hw_constraint_minmax(substream->runtime,
+					SNDRV_PCM_HW_PARAM_RATE,
+					first_runtime->rate,
+					first_runtime->rate);
+		}
+
+		dev->second_stream = substream;
+	}
+
+	snd_soc_dai_set_dma_data(dai, substream,
+			&dev->dma_params[substream->stream]);
+
+	return 0;
+}
+
+static void bcm2708_i2s_shutdown(struct snd_pcm_substream *substream,
+		struct snd_soc_dai *dai)
+{
+	struct bcm2708_i2s_dev *dev = snd_soc_dai_get_drvdata(dai);
+
+	bcm2708_i2s_stop(dev, substream);
+
+	if (dev->first_stream == substream)
+		dev->first_stream = dev->second_stream;
+
+	dev->second_stream = NULL;
+
+	/* If both streams are stopped, disable module and clock */
+	if (!dev->first_stream) {
+		/* Disable the module */
+		bcm2708_i2s_clear_bits(dev, BCM2708_I2S_CS_A_REG,
+				BCM2708_I2S_EN);
+
+		/*
+		 * Stopping clock is necessary, because stop does
+		 * not stop the clock when SND_SOC_DAIFMT_CONT
+		 */
+		bcm2708_i2s_stop_clock(dev);
+	}
+}
+
+static const struct snd_soc_dai_ops bcm2708_i2s_dai_ops = {
+	.startup	= bcm2708_i2s_startup,
+	.shutdown	= bcm2708_i2s_shutdown,
+	.prepare	= bcm2708_i2s_prepare,
+	.trigger	= bcm2708_i2s_trigger,
+	.hw_params	= bcm2708_i2s_hw_params,
+	.set_fmt	= bcm2708_i2s_set_dai_fmt,
+};
+
+static struct snd_soc_dai_driver bcm2708_i2s_dai = {
+	.playback = {
+		.channels_min = 2,
+		.channels_max = 2,
+		.rates =	SNDRV_PCM_RATE_8000_192000,
+		.formats =	SNDRV_PCM_FMTBIT_S16_LE
+				| SNDRV_PCM_FMTBIT_S32_LE
+		},
+	.capture = {
+		.channels_min = 2,
+		.channels_max = 2,
+		.rates =	SNDRV_PCM_RATE_8000_192000,
+		.formats =	SNDRV_PCM_FMTBIT_S16_LE
+				| SNDRV_PCM_FMTBIT_S32_LE
+		},
+	.ops = &bcm2708_i2s_dai_ops,
+	.symmetric_rates = 1
+};
+
+static void bcm2708_i2s_setup_gpio(void)
+{
+	/*
+	 * This is the common way to handle the GPIO pins for
+	 * the Raspberry Pi.
+	 * TODO Better way would be to handle
+	 * this in the device tree!
+	 */
+#define INP_GPIO(g) *(gpio+((g)/10)) &= ~(7<<(((g)%10)*3))
+#define SET_GPIO_ALT(g,a) *(gpio+(((g)/10))) |= (((a)<=3?(a)+4:(a)==4?3:2)<<(((g)%10)*3))
+
+	unsigned int *gpio;
+	int pin;
+	gpio = ioremap(GPIO_BASE, SZ_16K);
+
+	/* SPI is on GPIO 7..11 */
+	for (pin = 28; pin <= 31; pin++) {
+		INP_GPIO(pin);		/* set mode to GPIO input first */
+		SET_GPIO_ALT(pin, 2);	/* set mode to ALT 0 */
+	}
+#undef INP_GPIO
+#undef SET_GPIO_ALT
+}
+
+static int bcm2708_i2s_probe(struct platform_device *pdev)
+{
+	struct bcm2708_i2s_dev *dev;
+	int i;
+	void __iomem *base[2];
+
+	/* request both ioareas */
+	for (i = 0; i <= 1; i++) {
+		struct resource *mem, *ioarea;
+		mem = platform_get_resource(pdev, IORESOURCE_MEM, i);
+		if (!mem) {
+			dev_err(&pdev->dev, "I2S probe: Memory resource could not be found.\n");
+			return -ENODEV;
+		}
+
+		ioarea = devm_request_mem_region(&pdev->dev, mem->start,
+					   resource_size(mem),
+					   pdev->name);
+		if (!ioarea) {
+			dev_err(&pdev->dev, "I2S probe: Memory region already claimed.\n");
+			return -EBUSY;
+		}
+
+		base[i] = devm_ioremap(&pdev->dev, mem->start,
+				resource_size(mem));
+		if (!base[i]) {
+			dev_err(&pdev->dev, "I2S probe: ioremap failed.\n");
+			return -ENOMEM;
+		}
+	}
+
+	dev = devm_kzalloc(&pdev->dev, sizeof(struct bcm2708_i2s_dev),
+			   GFP_KERNEL);
+	if (!dev) {
+		dev_err(&pdev->dev, "I2S probe: kzalloc failed.\n");
+		return -ENOMEM;
+	}
+
+	dev->i2s_base = base[0];
+	dev->clk_base = base[1];
+
+	bcm2708_i2s_setup_gpio();
+
+	/* Set the appropriate DMA parameters */
+	dev->dma_params[SNDRV_PCM_STREAM_PLAYBACK].port_addr =
+		(dma_addr_t)BCM2708_I2S_FIFO_PHYSICAL_ADDR;
+	dev->dma_params[SNDRV_PCM_STREAM_CAPTURE].port_addr =
+		(dma_addr_t)BCM2708_I2S_FIFO_PHYSICAL_ADDR;
+
+	dev->dma_params[SNDRV_PCM_STREAM_PLAYBACK].dma_req =
+		BCM2708_DMA_DREQ_PCM_TX;
+	dev->dma_params[SNDRV_PCM_STREAM_CAPTURE].dma_req =
+		BCM2708_DMA_DREQ_PCM_RX;
+
+	/* Store the pdev */
+	dev->dev = &pdev->dev;
+	dev_set_drvdata(&pdev->dev, dev);
+
+	return snd_soc_register_dai(&pdev->dev, &bcm2708_i2s_dai);
+}
+
+static int bcm2708_i2s_remove(struct platform_device *pdev)
+{
+	snd_soc_unregister_dai(&pdev->dev);
+	return 0;
+}
+
+static struct platform_driver bcm2708_i2s_driver = {
+	.probe		= bcm2708_i2s_probe,
+	.remove		= bcm2708_i2s_remove,
+	.driver		= {
+		.name	= "bcm2708-i2s",
+		.owner	= THIS_MODULE,
+	},
+};
+
+module_platform_driver(bcm2708_i2s_driver);
+
+MODULE_AUTHOR("Florian Meier");
+MODULE_DESCRIPTION("BCM2708 I2S Interface");
+MODULE_LICENSE("GPL");
diff --git a/sound/soc/bcm2708/bcm2708-pcm.c b/sound/soc/bcm2708/bcm2708-pcm.c
new file mode 100644
index 0000000..4b3e688
--- /dev/null
+++ b/sound/soc/bcm2708/bcm2708-pcm.c
@@ -0,0 +1,303 @@
+/*
+ * ALSA PCM interface for Broadcom BCM2708 SoC
+ *
+ * Author:	Florian Meier, <[email-masked]>
+ *		Copyright 2013
+ *
+ * based on
+ *	ALSA PCM interface for the OMAP SoC
+ *	Copyright (C) 2008 Nokia Corporation
+ *	Contact: Jarkko Nikula <[email-masked]>
+ *	Peter Ujfalusi <[email-masked]>
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation; either version 2 of the License, or
+ * (at your option) any later version.
+ *
+ * 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.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program; if not, write to the Free Software
+ * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA
+ *
+ * TODO This should be transferred to the generic DMA engine driver
+ *	as soon as the official BCM2708 kernel migrates to 3.10.
+ *	Otherwise, it would be difficult to test.
+ */
+
+#include <linux/dma-mapping.h>
+#include <linux/slab.h>
+#include <linux/module.h>
+#include <linux/bcm2708-dmaengine.h>
+#include <sound/core.h>
+#include <sound/pcm.h>
+#include <sound/pcm_params.h>
+#include <sound/dmaengine_pcm.h>
+#include <sound/soc.h>
+
+#include "bcm2708-pcm.h"
+
+static const struct snd_pcm_hardware bcm2708_pcm_hardware = {
+	.info			= SNDRV_PCM_INFO_MMAP |
+				  SNDRV_PCM_INFO_MMAP_VALID |
+				  SNDRV_PCM_INFO_INTERLEAVED |
+				  SNDRV_PCM_INFO_PAUSE |
+				  SNDRV_PCM_INFO_RESUME |
+				  SNDRV_PCM_INFO_JOINT_DUPLEX |
+				  SNDRV_PCM_INFO_NO_PERIOD_WAKEUP,
+	.formats		= SNDRV_PCM_FMTBIT_S16_LE |
+				  SNDRV_PCM_FMTBIT_S32_LE,
+	.period_bytes_min	= 32,
+	.period_bytes_max	= 64 * 1024,
+	.periods_min		= 2,
+	.periods_max		= 255,
+	.buffer_bytes_max	= 128 * 1024,
+};
+
+static int bcm2708_pcm_hw_params(struct snd_pcm_substream *substream,
+			      struct snd_pcm_hw_params *params)
+{
+	struct snd_pcm_runtime *runtime = substream->runtime;
+	struct snd_soc_pcm_runtime *rtd = substream->private_data;
+	struct bcm2708_pcm_dma_data *dma_data;
+	struct bcm2708_dma_slave_config config;
+	struct dma_chan *chan;
+	int err = 0;
+
+	/* get DMA data (e.g. FIFO address and DREQ) */
+	dma_data = snd_soc_dai_get_dma_data(rtd->cpu_dai, substream);
+
+	/*
+	 * There seems to be no use for bufferless
+	 * transfer with this SoC.
+	 */
+	if (!dma_data)
+		return 0;
+
+	snd_pcm_set_runtime_buffer(substream, &substream->dma_buffer);
+	runtime->dma_bytes = params_buffer_bytes(params);
+
+	chan = snd_dmaengine_pcm_get_chan(substream);
+	if (!chan)
+		return -EINVAL;
+
+	/* fills in addr_width and direction */
+	err = snd_hwparams_to_dma_slave_config(substream, params, &config.cfg);
+	if (err)
+		return err;
+
+	/* Override the *_dma addr_width if requested by the DAI driver */
+	if (substream->stream == SNDRV_PCM_STREAM_PLAYBACK)
+		config.cfg.dst_addr_width = DMA_SLAVE_BUSWIDTH_4_BYTES;
+	else
+		config.cfg.src_addr_width = DMA_SLAVE_BUSWIDTH_4_BYTES;
+
+	config.cfg.src_addr = dma_data->port_addr;
+	config.cfg.dst_addr = dma_data->port_addr;
+	config.cfg.src_maxburst = dma_data->packet_size;
+	config.cfg.dst_maxburst = dma_data->packet_size;
+	config.sync_dreq = dma_data->dma_req;
+
+	return dmaengine_slave_config(chan, &config.cfg);
+}
+
+static int bcm2708_pcm_hw_free(struct snd_pcm_substream *substream)
+{
+	snd_pcm_set_runtime_buffer(substream, NULL);
+	return 0;
+}
+
+static int bcm2708_pcm_trigger(struct snd_pcm_substream *substream, int cmd)
+{
+	struct snd_soc_pcm_runtime *rtd = substream->private_data;
+	struct bcm2708_pcm_dma_data *dma_data;
+	int ret = 0;
+
+	dma_data = snd_soc_dai_get_dma_data(rtd->cpu_dai, substream);
+
+	switch (cmd) {
+	case SNDRV_PCM_TRIGGER_START:
+	case SNDRV_PCM_TRIGGER_RESUME:
+	case SNDRV_PCM_TRIGGER_PAUSE_RELEASE:
+		break;
+
+	case SNDRV_PCM_TRIGGER_STOP:
+	case SNDRV_PCM_TRIGGER_SUSPEND:
+	case SNDRV_PCM_TRIGGER_PAUSE_PUSH:
+		break;
+	default:
+		ret = -EINVAL;
+	}
+
+	if (ret == 0)
+		ret = snd_dmaengine_pcm_trigger(substream, cmd);
+
+	return ret;
+}
+
+static snd_pcm_uframes_t bcm2708_pcm_pointer(
+		struct snd_pcm_substream *substream)
+{
+	return snd_dmaengine_pcm_pointer(substream);
+}
+
+static int bcm2708_pcm_open(struct snd_pcm_substream *substream)
+{
+	struct snd_pcm_runtime *runtime = substream->runtime;
+	struct snd_soc_pcm_runtime *rtd = substream->private_data;
+	struct bcm2708_pcm_dma_data *dma_data;
+	int ret;
+
+	snd_soc_set_runtime_hwparams(substream, &bcm2708_pcm_hardware);
+
+	/* Ensure that buffer size is a multiple of period size */
+	ret = snd_pcm_hw_constraint_integer(runtime,
+					    SNDRV_PCM_HW_PARAM_PERIODS);
+	if (ret < 0)
+		return ret;
+
+	dma_data = snd_soc_dai_get_dma_data(rtd->cpu_dai, substream);
+	return snd_dmaengine_pcm_open(substream, NULL, NULL);
+}
+
+static int bcm2708_pcm_close(struct snd_pcm_substream *substream)
+{
+	snd_dmaengine_pcm_close(substream);
+	return 0;
+}
+
+static int bcm2708_pcm_mmap(struct snd_pcm_substream *substream,
+	struct vm_area_struct *vma)
+{
+	struct snd_pcm_runtime *runtime = substream->runtime;
+
+	return dma_mmap_writecombine(substream->pcm->card->dev, vma,
+				     runtime->dma_area,
+				     runtime->dma_addr,
+				     runtime->dma_bytes);
+}
+
+static struct snd_pcm_ops bcm2708_pcm_ops = {
+	.open		= bcm2708_pcm_open,
+	.close		= bcm2708_pcm_close,
+	.ioctl		= snd_pcm_lib_ioctl,
+	.hw_params	= bcm2708_pcm_hw_params,
+	.hw_free	= bcm2708_pcm_hw_free,
+	.trigger	= bcm2708_pcm_trigger,
+	.pointer	= bcm2708_pcm_pointer,
+	.mmap		= bcm2708_pcm_mmap,
+};
+
+static u64 bcm2708_pcm_dmamask = DMA_BIT_MASK(64);
+
+static int bcm2708_pcm_preallocate_dma_buffer(struct snd_pcm *pcm,
+	int stream)
+{
+	struct snd_pcm_substream *substream = pcm->streams[stream].substream;
+	struct snd_dma_buffer *buf = &substream->dma_buffer;
+	size_t size = bcm2708_pcm_hardware.buffer_bytes_max;
+
+	buf->dev.type = SNDRV_DMA_TYPE_DEV;
+	buf->dev.dev = pcm->card->dev;
+	buf->private_data = NULL;
+	buf->area = dma_alloc_writecombine(pcm->card->dev, size,
+					   &buf->addr, GFP_KERNEL);
+	if (!buf->area)
+		return -ENOMEM;
+
+	buf->bytes = size;
+	return 0;
+}
+
+static void bcm2708_pcm_free_dma_buffers(struct snd_pcm *pcm)
+{
+	struct snd_pcm_substream *substream;
+	struct snd_dma_buffer *buf;
+	int stream;
+
+	for (stream = 0; stream < 2; stream++) {
+		substream = pcm->streams[stream].substream;
+		if (!substream)
+			continue;
+
+		buf = &substream->dma_buffer;
+		if (!buf->area)
+			continue;
+
+		dma_free_writecombine(pcm->card->dev, buf->bytes,
+				      buf->area, buf->addr);
+		buf->area = NULL;
+	}
+}
+
+static int bcm2708_pcm_new(struct snd_soc_pcm_runtime *rtd)
+{
+	struct snd_card *card = rtd->card->snd_card;
+	struct snd_pcm *pcm = rtd->pcm;
+	int ret = 0;
+
+	if (!card->dev->dma_mask)
+		card->dev->dma_mask = &bcm2708_pcm_dmamask;
+	if (!card->dev->coherent_dma_mask)
+		card->dev->coherent_dma_mask = DMA_BIT_MASK(64);
+
+	if (pcm->streams[SNDRV_PCM_STREAM_PLAYBACK].substream) {
+		ret = bcm2708_pcm_preallocate_dma_buffer(pcm,
+			SNDRV_PCM_STREAM_PLAYBACK);
+		if (ret)
+			goto out;
+	}
+
+	if (pcm->streams[SNDRV_PCM_STREAM_CAPTURE].substream) {
+		ret = bcm2708_pcm_preallocate_dma_buffer(pcm,
+			SNDRV_PCM_STREAM_CAPTURE);
+		if (ret)
+			goto out;
+	}
+
+out:
+	/* free preallocated buffers in case of error */
+	if (ret)
+		bcm2708_pcm_free_dma_buffers(pcm);
+
+	return ret;
+}
+
+static struct snd_soc_platform_driver bcm2708_soc_platform = {
+	.ops		= &bcm2708_pcm_ops,
+	.pcm_new	= bcm2708_pcm_new,
+	.pcm_free	= bcm2708_pcm_free_dma_buffers,
+};
+
+static int bcm2708_pcm_probe(struct platform_device *pdev)
+{
+	return snd_soc_register_platform(&pdev->dev,
+			&bcm2708_soc_platform);
+}
+
+static int bcm2708_pcm_remove(struct platform_device *pdev)
+{
+	snd_soc_unregister_platform(&pdev->dev);
+	return 0;
+}
+
+static struct platform_driver bcm2708_pcm_driver = {
+	.driver = {
+			.name = "bcm2708-pcm-audio",
+			.owner = THIS_MODULE,
+	},
+
+	.probe = bcm2708_pcm_probe,
+	.remove = bcm2708_pcm_remove,
+};
+
+module_platform_driver(bcm2708_pcm_driver);
+
+MODULE_AUTHOR("Florian Meier");
+MODULE_DESCRIPTION("BCM2708 PCM DMA module");
+MODULE_LICENSE("GPL");
+MODULE_ALIAS("platform:bcm2708-pcm-audio");
diff --git a/sound/soc/bcm2708/bcm2708-pcm.h b/sound/soc/bcm2708/bcm2708-pcm.h
new file mode 100644
index 0000000..e6a6acb
--- /dev/null
+++ b/sound/soc/bcm2708/bcm2708-pcm.h
@@ -0,0 +1,40 @@
+/*
+ * ALSA PCM interface for Broadcom BCM2708 SoC
+ *
+ * Author:	Florian Meier, <[email-masked]>
+ *		Copyright 2013
+ *
+ * based on
+ *	ALSA PCM interface for the OMAP SoC
+ *	Copyright (C) 2008 Nokia Corporation
+ *	Contact: Jarkko Nikula <[email-masked]>
+ *		 Peter Ujfalusi <[email-masked]>
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation; either version 2 of the License, or
+ * (at your option) any later version.
+ *
+ * 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.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program; if not, write to the Free Software
+ * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA
+ */
+
+#ifndef __BCM2708_PCM_H__
+#define __BCM2708_PCM_H__
+
+struct snd_pcm_substream;
+
+struct bcm2708_pcm_dma_data {
+	char		*name;		/* stream identifier */
+	int		dma_req;	/* DMA request line */
+	unsigned long	port_addr;	/* transmit/receive register */
+	int		packet_size;
+};
+
+#endif
diff --git a/sound/soc/bcm2708/rpi-mbed.c b/sound/soc/bcm2708/rpi-mbed.c
new file mode 100644
index 0000000..cb8d25f
--- /dev/null
+++ b/sound/soc/bcm2708/rpi-mbed.c
@@ -0,0 +1,113 @@
+/*
+ * ASoC driver for mbed AudioCODEC (with a TLV320AIC23B)
+ * connected to a Raspberry Pi
+ *
+ * Author:	Florian Meier, <[email-masked]>
+ *		Copyright 2013
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation; either version 2 of the License, or
+ * (at your option) any later version.
+ *
+ * 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.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program; if not, write to the Free Software
+ * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA
+ */
+
+#include <linux/module.h>
+#include <linux/platform_device.h>
+
+#include <sound/core.h>
+#include <sound/pcm.h>
+#include <sound/soc.h>
+#include <sound/jack.h>
+
+#include "../codecs/tlv320aic23.h"
+
+static int snd_rpi_mbed_init(struct snd_soc_pcm_runtime *rtd)
+{
+	return 0;
+}
+
+static int snd_rpi_mbed_hw_params(struct snd_pcm_substream *substream,
+				       struct snd_pcm_hw_params *params)
+{
+	struct snd_soc_pcm_runtime *rtd = substream->private_data;
+	struct snd_soc_dai *codec_dai = rtd->codec_dai;
+	int sysclk;
+
+	sysclk = 12000000; /* this is fixed on this board */
+
+	/* set tlv320aic23 sysclk */
+	snd_soc_dai_set_sysclk(codec_dai, 0, sysclk, 0);
+
+	return 0;
+}
+
+/* machine stream operations */
+static struct snd_soc_ops snd_rpi_mbed_ops = {
+	.hw_params = snd_rpi_mbed_hw_params,
+};
+
+static struct snd_soc_dai_link snd_rpi_mbed_dai[] = {
+{
+	.name		= "TLV320AIC23",
+	.stream_name	= "TLV320AIC23 HiFi",
+	.cpu_dai_name	= "bcm2708-i2s.0",
+	.codec_dai_name	= "tlv320aic23-hifi",
+	.platform_name	= "bcm2708-pcm-audio.0",
+	.codec_name	= "tlv320aic23-codec.1-001b",
+	.dai_fmt	= SND_SOC_DAIFMT_I2S | SND_SOC_DAIFMT_NB_NF |
+				SND_SOC_DAIFMT_CBS_CFS,
+	.ops		= &snd_rpi_mbed_ops,
+	.init		= snd_rpi_mbed_init,
+},
+};
+
+/* audio machine driver */
+static struct snd_soc_card snd_rpi_mbed = {
+	.name	 = "snd_rpi_mbed",
+	.dai_link     = snd_rpi_mbed_dai,
+	.num_links    = ARRAY_SIZE(snd_rpi_mbed_dai),
+};
+
+static int snd_rpi_mbed_probe(struct platform_device *pdev)
+{
+	int ret = 0;
+
+	snd_rpi_mbed.dev = &pdev->dev;
+	ret = snd_soc_register_card(&snd_rpi_mbed);
+	if (ret) {
+		dev_err(&pdev->dev,
+				"snd_soc_register_card() failed: %d\n", ret);
+	}
+
+	return ret;
+}
+
+
+static int snd_rpi_mbed_remove(struct platform_device *pdev)
+{
+	return snd_soc_unregister_card(&snd_rpi_mbed);
+}
+
+static struct platform_driver snd_rpi_mbed_driver = {
+	.driver = {
+		.name   = "snd-rpi-mbed",
+		.owner  = THIS_MODULE,
+	},
+	.probe	  = snd_rpi_mbed_probe,
+	.remove	 = snd_rpi_mbed_remove,
+};
+
+module_platform_driver(snd_rpi_mbed_driver);
+
+MODULE_AUTHOR("Florian Meier");
+MODULE_DESCRIPTION("ASoC Driver for Raspberry Pi connected to mbed AudioCODEC");
+MODULE_LICENSE("GPL");
diff --git a/sound/soc/bcm2708/rpi-proto.c b/sound/soc/bcm2708/rpi-proto.c
new file mode 100644
index 0000000..25be85a
--- /dev/null
+++ b/sound/soc/bcm2708/rpi-proto.c
@@ -0,0 +1,131 @@
+/*
+ * ASoC driver for PROTO AudioCODEC (with a WM8731)
+ * connected to a Raspberry Pi
+ *
+ * Author:	Florian Meier, <[email-masked]>
+ *		Copyright 2013
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation; either version 2 of the License, or
+ * (at your option) any later version.
+ *
+ * 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.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program; if not, write to the Free Software
+ * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA
+ */
+
+#include <linux/module.h>
+#include <linux/platform_device.h>
+
+#include <sound/core.h>
+#include <sound/pcm.h>
+#include <sound/soc.h>
+#include <sound/jack.h>
+
+#include "../codecs/wm8731.h"
+
+static const unsigned int wm8731_rates_12288000[] = {
+	8000, 32000, 48000, 96000,
+};
+
+static struct snd_pcm_hw_constraint_list wm8731_constraints_12288000 = {
+	.list = wm8731_rates_12288000,
+	.count = ARRAY_SIZE(wm8731_rates_12288000),
+};
+
+static int snd_rpi_proto_startup(struct snd_pcm_substream *substream)
+{
+	/* Setup constraints, because there is a 12.288 MHz XTAL on the board */
+	snd_pcm_hw_constraint_list(substream->runtime, 0,
+				SNDRV_PCM_HW_PARAM_RATE,
+				&wm8731_constraints_12288000);
+	return 0;
+}
+
+static int snd_rpi_proto_hw_params(struct snd_pcm_substream *substream,
+				       struct snd_pcm_hw_params *params)
+{
+	struct snd_soc_pcm_runtime *rtd = substream->private_data;
+	struct snd_soc_dai *codec_dai = rtd->codec_dai;
+	int sysclk = 12288000; /* This is fixed on this board */
+
+	/* Set proto sysclk */
+	int ret = snd_soc_dai_set_sysclk(codec_dai, WM8731_SYSCLK_XTAL,
+		sysclk, SND_SOC_CLOCK_IN);
+	if (ret < 0) {
+		dev_err(substream->pcm->dev,
+				"Failed to set WM8731 SYSCLK: %d\n", ret);
+		return ret;
+	}
+
+	return 0;
+}
+
+/* machine stream operations */
+static struct snd_soc_ops snd_rpi_proto_ops = {
+	.startup = snd_rpi_proto_startup,
+	.hw_params = snd_rpi_proto_hw_params,
+};
+
+static struct snd_soc_dai_link snd_rpi_proto_dai[] = {
+{
+	.name		= "WM8731",
+	.stream_name	= "WM8731 HiFi",
+	.cpu_dai_name	= "bcm2708-i2s.0",
+	.codec_dai_name	= "wm8731-hifi",
+	.platform_name	= "bcm2708-pcm-audio.0",
+	.codec_name	= "wm8731.1-001a",
+	.dai_fmt	= SND_SOC_DAIFMT_I2S
+				| SND_SOC_DAIFMT_NB_NF
+				| SND_SOC_DAIFMT_CBM_CFM,
+	.ops		= &snd_rpi_proto_ops,
+},
+};
+
+/* audio machine driver */
+static struct snd_soc_card snd_rpi_proto = {
+	.name		= "snd_rpi_proto",
+	.dai_link	= snd_rpi_proto_dai,
+	.num_links	= ARRAY_SIZE(snd_rpi_proto_dai),
+};
+
+static int snd_rpi_proto_probe(struct platform_device *pdev)
+{
+	int ret = 0;
+
+	snd_rpi_proto.dev = &pdev->dev;
+	ret = snd_soc_register_card(&snd_rpi_proto);
+	if (ret) {
+		dev_err(&pdev->dev,
+				"snd_soc_register_card() failed: %d\n", ret);
+	}
+
+	return ret;
+}
+
+
+static int snd_rpi_proto_remove(struct platform_device *pdev)
+{
+	return snd_soc_unregister_card(&snd_rpi_proto);
+}
+
+static struct platform_driver snd_rpi_proto_driver = {
+	.driver = {
+		.name   = "snd-rpi-proto",
+		.owner  = THIS_MODULE,
+	},
+	.probe	  = snd_rpi_proto_probe,
+	.remove	 = snd_rpi_proto_remove,
+};
+
+module_platform_driver(snd_rpi_proto_driver);
+
+MODULE_AUTHOR("Florian Meier");
+MODULE_DESCRIPTION("ASoC Driver for Raspberry Pi connected to PROTO board (WM8731)");
+MODULE_LICENSE("GPL");
-- 
1.7.9.5