ASoC: multi-component - ASoC Multi-Component Support

This patch extends the ASoC API to allow sound cards to have more than one
CODEC and more than one platform DMA controller. This is achieved by dividing
some current ASoC structures that contain both driver data and device data into
structures that only either contain device data or driver data. i.e.

 struct snd_soc_codec    --->  struct snd_soc_codec (device data)
                          +->  struct snd_soc_codec_driver (driver data)

 struct snd_soc_platform --->  struct snd_soc_platform (device data)
                          +->  struct snd_soc_platform_driver (driver data)

 struct snd_soc_dai      --->  struct snd_soc_dai (device data)
                          +->  struct snd_soc_dai_driver (driver data)

 struct snd_soc_device   --->  deleted

This now allows ASoC to be more tightly aligned with the Linux driver model and
also means that every ASoC codec, platform and (platform) DAI is a kernel
device. ASoC component private data is now stored as device private data.

The ASoC sound card struct snd_soc_card has also been updated to store lists
of it's components rather than a pointer to a codec and platform. The PCM
runtime struct soc_pcm_runtime now has pointers to all its components.

This patch adds DAPM support for ASoC multi-component and removes struct
snd_soc_socdev from DAPM core. All DAPM calls are now made on a card, codec
or runtime PCM level basis rather than using snd_soc_socdev.

Other notable multi-component changes:-

 * Stream operations now de-reference less structures.
 * close_delayed work() now runs on a DAI basis rather than looping all DAIs
   in a card.
 * PM suspend()/resume() operations can now handle N CODECs and Platforms
   per sound card.
 * Added soc_bind_dai_link() to bind the component devices to the sound card.
 * Added soc_dai_link_probe() and soc_dai_link_remove() to probe and remove
   DAI link components.
 * sysfs entries can now be registered per component per card.
 * snd_soc_new_pcms() functionailty rolled into dai_link_probe().
 * snd_soc_register_codec() now does all the codec list and mutex init.

This patch changes the probe() and remove() of the CODEC drivers as follows:-

 o Make CODEC driver a platform driver
 o Moved all struct snd_soc_codec list, mutex, etc initialiasation to core.
 o Removed all static codec pointers (drivers now support > 1 codec dev)
 o snd_soc_register_pcms() now done by core.
 o snd_soc_register_dai() folded into snd_soc_register_codec().

CS4270 portions:
Acked-by: Timur Tabi <timur@freescale.com>

Some TLV320aic23 and Cirrus platform fixes.
Signed-off-by: Ryan Mallon <ryan@bluewatersys.com>

TI CODEC and OMAP fixes
Signed-off-by: Peter Ujfalusi <peter.ujfalusi@nokia.com>
Signed-off-by: Janusz Krzysztofik <jkrzyszt@tis.icnet.pl>
Signed-off-by: Jarkko Nikula <jhnikula@gmail.com>

Samsung platform and misc fixes :-
Signed-off-by: Chanwoo Choi <cw00.choi@samsung.com>
Signed-off-by: Joonyoung Shim <jy0922.shim@samsung.com>
Signed-off-by: Kyungmin Park <kyungmin.park@samsung.com>
Reviewed-by: Jassi Brar <jassi.brar@samsung.com>
Signed-off-by: Seungwhan Youn <sw.youn@samsung.com>

MPC8610 and PPC fixes.
Signed-off-by: Timur Tabi <timur@freescale.com>

i.MX fixes and some core fixes.
Signed-off-by: Sascha Hauer <s.hauer@pengutronix.de>

J4740 platform fixes:-
Signed-off-by: Lars-Peter Clausen <lars@metafoo.de>

CC: Tony Lindgren <tony@atomide.com>
CC: Nicolas Ferre <nicolas.ferre@atmel.com>
CC: Kevin Hilman <khilman@deeprootsystems.com>
CC: Sascha Hauer <s.hauer@pengutronix.de>
CC: Atsushi Nemoto <anemo@mba.ocn.ne.jp>
CC: Kuninori Morimoto <morimoto.kuninori@renesas.com>
CC: Daniel Gloeckner <dg@emlix.com>
CC: Manuel Lauss <mano@roarinelk.homelinux.net>
CC: Mike Frysinger <vapier.adi@gmail.com>
CC: Arnaud Patard <apatard@mandriva.com>
CC: Wan ZongShun <mcuos.com@gmail.com>

Acked-by: Mark Brown <broonie@opensource.wolfsonmicro.com>
Signed-off-by: Liam Girdwood <lrg@slimlogic.co.uk>

1 files changed, 190 insertions, 122 deletions

diff --git a/sound/soc/fsl/fsl_dma.c b/sound/soc/fsl/fsl_dma.c
index 410c7496a18..d09e1941b1f 100644
--- a/sound/soc/fsl/fsl_dma.c
+++ b/sound/soc/fsl/fsl_dma.c
@@ -3,10 +3,11 @@
  *
  * Author: Timur Tabi <timur@freescale.com>
  *
- * Copyright 2007-2008 Freescale Semiconductor, Inc.  This file is licensed
- * under the terms of the GNU General Public License version 2.  This
- * program is licensed "as is" without any warranty of any kind, whether
- * express or implied.
+ * Copyright 2007-2010 Freescale Semiconductor, Inc.
+ *
+ * This file is licensed under the terms of the GNU General Public License
+ * version 2.  This program is licensed "as is" without any warranty of any
+ * kind, whether express or implied.
  *
  * This driver implements ASoC support for the Elo DMA controller, which is
  * the DMA controller on Freescale 83xx, 85xx, and 86xx SOCs. In ALSA terms,
@@ -20,6 +21,8 @@
 #include <linux/interrupt.h>
 #include <linux/delay.h>
 #include <linux/gfp.h>
+#include <linux/of_platform.h>
+#include <linux/list.h>
 
 #include <sound/core.h>
 #include <sound/pcm.h>
@@ -29,6 +32,7 @@
 #include <asm/io.h>
 
 #include "fsl_dma.h"
+#include "fsl_ssi.h"	/* For the offset of stx0 and srx0 */
 
 /*
  * The formats that the DMA controller supports, which is anything
@@ -52,26 +56,16 @@
 #define FSLDMA_PCM_RATES (SNDRV_PCM_RATE_5512 | SNDRV_PCM_RATE_8000_192000 | \
 			  SNDRV_PCM_RATE_CONTINUOUS)
 
-/* DMA global data.  This structure is used by fsl_dma_open() to determine
- * which DMA channels to assign to a substream.  Unfortunately, ASoC V1 does
- * not allow the machine driver to provide this information to the PCM
- * driver in advance, and there's no way to differentiate between the two
- * DMA controllers.  So for now, this driver only supports one SSI device
- * using two DMA channels.  We cannot support multiple DMA devices.
- *
- * ssi_stx_phys: bus address of SSI STX register
- * ssi_srx_phys: bus address of SSI SRX register
- * dma_channel: pointer to the DMA channel's registers
- * irq: IRQ for this DMA channel
- * assigned: set to 1 if that DMA channel is assigned to a substream
- */
-static struct {
+struct dma_object {
+	struct list_head list;
+	struct snd_soc_platform_driver dai;
 	dma_addr_t ssi_stx_phys;
 	dma_addr_t ssi_srx_phys;
-	struct ccsr_dma_channel __iomem *dma_channel[2];
-	unsigned int irq[2];
-	unsigned int assigned[2];
-} dma_global_data;
+	struct ccsr_dma_channel __iomem *channel;
+	unsigned int irq;
+	bool assigned;
+	char path[1];
+};
 
 /*
  * The number of DMA links to use.  Two is the bare minimum, but if you
@@ -88,8 +82,6 @@ static struct {
  * structure.
  *
  * @link[]: array of link descriptors
- * @controller_id: which DMA controller (0, 1, ...)
- * @channel_id: which DMA channel on the controller (0, 1, 2, ...)
  * @dma_channel: pointer to the DMA channel's registers
  * @irq: IRQ for this DMA channel
  * @substream: pointer to the substream object, needed by the ISR
@@ -104,8 +96,6 @@ static struct {
  */
 struct fsl_dma_private {
 	struct fsl_dma_link_descriptor link[NUM_DMA_LINKS];
-	unsigned int controller_id;
-	unsigned int channel_id;
 	struct ccsr_dma_channel __iomem *dma_channel;
 	unsigned int irq;
 	struct snd_pcm_substream *substream;
@@ -212,6 +202,9 @@ static void fsl_dma_update_pointers(struct fsl_dma_private *dma_private)
 static irqreturn_t fsl_dma_isr(int irq, void *dev_id)
 {
 	struct fsl_dma_private *dma_private = dev_id;
+	struct snd_pcm_substream *substream = dma_private->substream;
+	struct snd_soc_pcm_runtime *rtd = substream->private_data;
+	struct device *dev = rtd->platform->dev;
 	struct ccsr_dma_channel __iomem *dma_channel = dma_private->dma_channel;
 	irqreturn_t ret = IRQ_NONE;
 	u32 sr, sr2 = 0;
@@ -222,11 +215,8 @@ static irqreturn_t fsl_dma_isr(int irq, void *dev_id)
 	sr = in_be32(&dma_channel->sr);
 
 	if (sr & CCSR_DMA_SR_TE) {
-		dev_err(dma_private->substream->pcm->card->dev,
-			"DMA transmit error (controller=%u channel=%u irq=%u\n",
-			dma_private->controller_id,
-			dma_private->channel_id, irq);
-		fsl_dma_abort_stream(dma_private->substream);
+		dev_err(dev, "dma transmit error\n");
+		fsl_dma_abort_stream(substream);
 		sr2 |= CCSR_DMA_SR_TE;
 		ret = IRQ_HANDLED;
 	}
@@ -235,11 +225,8 @@ static irqreturn_t fsl_dma_isr(int irq, void *dev_id)
 		ret = IRQ_HANDLED;
 
 	if (sr & CCSR_DMA_SR_PE) {
-		dev_err(dma_private->substream->pcm->card->dev,
-			"DMA%u programming error (channel=%u irq=%u)\n",
-			dma_private->controller_id,
-			dma_private->channel_id, irq);
-		fsl_dma_abort_stream(dma_private->substream);
+		dev_err(dev, "dma programming error\n");
+		fsl_dma_abort_stream(substream);
 		sr2 |= CCSR_DMA_SR_PE;
 		ret = IRQ_HANDLED;
 	}
@@ -253,8 +240,6 @@ static irqreturn_t fsl_dma_isr(int irq, void *dev_id)
 		ret = IRQ_HANDLED;
 
 	if (sr & CCSR_DMA_SR_EOSI) {
-		struct snd_pcm_substream *substream = dma_private->substream;
-
 		/* Tell ALSA we completed a period. */
 		snd_pcm_period_elapsed(substream);
 
@@ -305,10 +290,8 @@ static int fsl_dma_new(struct snd_card *card, struct snd_soc_dai *dai,
 		fsl_dma_hardware.buffer_bytes_max,
 		&pcm->streams[0].substream->dma_buffer);
 	if (ret) {
-		dev_err(card->dev,
-			"Can't allocate playback DMA buffer (size=%u)\n",
-			fsl_dma_hardware.buffer_bytes_max);
-		return -ENOMEM;
+		dev_err(card->dev, "can't allocate playback dma buffer\n");
+		return ret;
 	}
 
 	ret = snd_dma_alloc_pages(SNDRV_DMA_TYPE_DEV, card->dev,
@@ -316,10 +299,8 @@ static int fsl_dma_new(struct snd_card *card, struct snd_soc_dai *dai,
 		&pcm->streams[1].substream->dma_buffer);
 	if (ret) {
 		snd_dma_free_pages(&pcm->streams[0].substream->dma_buffer);
-		dev_err(card->dev,
-			"Can't allocate capture DMA buffer (size=%u)\n",
-			fsl_dma_hardware.buffer_bytes_max);
-		return -ENOMEM;
+		dev_err(card->dev, "can't allocate capture dma buffer\n");
+		return ret;
 	}
 
 	return 0;
@@ -390,6 +371,10 @@ static int fsl_dma_new(struct snd_card *card, struct snd_soc_dai *dai,
 static int fsl_dma_open(struct snd_pcm_substream *substream)
 {
 	struct snd_pcm_runtime *runtime = substream->runtime;
+	struct snd_soc_pcm_runtime *rtd = substream->private_data;
+	struct device *dev = rtd->platform->dev;
+	struct dma_object *dma =
+		container_of(rtd->platform->driver, struct dma_object, dai);
 	struct fsl_dma_private *dma_private;
 	struct ccsr_dma_channel __iomem *dma_channel;
 	dma_addr_t ld_buf_phys;
@@ -407,52 +392,44 @@ static int fsl_dma_open(struct snd_pcm_substream *substream)
 	ret = snd_pcm_hw_constraint_integer(runtime,
 		SNDRV_PCM_HW_PARAM_PERIODS);
 	if (ret < 0) {
-		dev_err(substream->pcm->card->dev, "invalid buffer size\n");
+		dev_err(dev, "invalid buffer size\n");
 		return ret;
 	}
 
 	channel = substream->stream == SNDRV_PCM_STREAM_PLAYBACK ? 0 : 1;
 
-	if (dma_global_data.assigned[channel]) {
-		dev_err(substream->pcm->card->dev,
-			"DMA channel already assigned\n");
+	if (dma->assigned) {
+		dev_err(dev, "dma channel already assigned\n");
 		return -EBUSY;
 	}
 
-	dma_private = dma_alloc_coherent(substream->pcm->card->dev,
-		sizeof(struct fsl_dma_private), &ld_buf_phys, GFP_KERNEL);
+	dma_private = dma_alloc_coherent(dev, sizeof(struct fsl_dma_private),
+					 &ld_buf_phys, GFP_KERNEL);
 	if (!dma_private) {
-		dev_err(substream->pcm->card->dev,
-			"can't allocate DMA private data\n");
+		dev_err(dev, "can't allocate dma private data\n");
 		return -ENOMEM;
 	}
 	if (substream->stream == SNDRV_PCM_STREAM_PLAYBACK)
-		dma_private->ssi_sxx_phys = dma_global_data.ssi_stx_phys;
+		dma_private->ssi_sxx_phys = dma->ssi_stx_phys;
 	else
-		dma_private->ssi_sxx_phys = dma_global_data.ssi_srx_phys;
+		dma_private->ssi_sxx_phys = dma->ssi_srx_phys;
 
-	dma_private->dma_channel = dma_global_data.dma_channel[channel];
-	dma_private->irq = dma_global_data.irq[channel];
+	dma_private->dma_channel = dma->channel;
+	dma_private->irq = dma->irq;
 	dma_private->substream = substream;
 	dma_private->ld_buf_phys = ld_buf_phys;
 	dma_private->dma_buf_phys = substream->dma_buffer.addr;
 
-	/* We only support one DMA controller for now */
-	dma_private->controller_id = 0;
-	dma_private->channel_id = channel;
-
 	ret = request_irq(dma_private->irq, fsl_dma_isr, 0, "DMA", dma_private);
 	if (ret) {
-		dev_err(substream->pcm->card->dev,
-			"can't register ISR for IRQ %u (ret=%i)\n",
+		dev_err(dev, "can't register ISR for IRQ %u (ret=%i)\n",
 			dma_private->irq, ret);
-		dma_free_coherent(substream->pcm->card->dev,
-			sizeof(struct fsl_dma_private),
+		dma_free_coherent(dev, sizeof(struct fsl_dma_private),
 			dma_private, dma_private->ld_buf_phys);
 		return ret;
 	}
 
-	dma_global_data.assigned[channel] = 1;
+	dma->assigned = 1;
 
 	snd_pcm_set_runtime_buffer(substream, &substream->dma_buffer);
 	snd_soc_set_runtime_hwparams(substream, &fsl_dma_hardware);
@@ -546,6 +523,8 @@ static int fsl_dma_hw_params(struct snd_pcm_substream *substream,
 {
 	struct snd_pcm_runtime *runtime = substream->runtime;
 	struct fsl_dma_private *dma_private = runtime->private_data;
+	struct snd_soc_pcm_runtime *rtd = substream->private_data;
+	struct device *dev = rtd->platform->dev;
 
 	/* Number of bits per sample */
 	unsigned int sample_size =
@@ -606,8 +585,7 @@ static int fsl_dma_hw_params(struct snd_pcm_substream *substream,
 		break;
 	default:
 		/* We should never get here */
-		dev_err(substream->pcm->card->dev,
-			"unsupported sample size %u\n", sample_size);
+		dev_err(dev, "unsupported sample size %u\n", sample_size);
 		return -EINVAL;
 	}
 
@@ -689,6 +667,8 @@ static snd_pcm_uframes_t fsl_dma_pointer(struct snd_pcm_substream *substream)
 {
 	struct snd_pcm_runtime *runtime = substream->runtime;
 	struct fsl_dma_private *dma_private = runtime->private_data;
+	struct snd_soc_pcm_runtime *rtd = substream->private_data;
+	struct device *dev = rtd->platform->dev;
 	struct ccsr_dma_channel __iomem *dma_channel = dma_private->dma_channel;
 	dma_addr_t position;
 	snd_pcm_uframes_t frames;
@@ -710,8 +690,7 @@ static snd_pcm_uframes_t fsl_dma_pointer(struct snd_pcm_substream *substream)
 
 	if ((position < dma_private->dma_buf_phys) ||
 	    (position > dma_private->dma_buf_end)) {
-		dev_err(substream->pcm->card->dev,
-			"dma pointer is out of range, halting stream\n");
+		dev_err(dev, "dma pointer is out of range, halting stream\n");
 		return SNDRV_PCM_POS_XRUN;
 	}
 
@@ -772,26 +751,28 @@ static int fsl_dma_close(struct snd_pcm_substream *substream)
 {
 	struct snd_pcm_runtime *runtime = substream->runtime;
 	struct fsl_dma_private *dma_private = runtime->private_data;
-	int dir = substream->stream == SNDRV_PCM_STREAM_PLAYBACK ? 0 : 1;
+	struct snd_soc_pcm_runtime *rtd = substream->private_data;
+	struct device *dev = rtd->platform->dev;
+	struct dma_object *dma =
+		container_of(rtd->platform->driver, struct dma_object, dai);
 
 	if (dma_private) {
 		if (dma_private->irq)
 			free_irq(dma_private->irq, dma_private);
 
 		if (dma_private->ld_buf_phys) {
-			dma_unmap_single(substream->pcm->card->dev,
-				dma_private->ld_buf_phys,
-				sizeof(dma_private->link), DMA_TO_DEVICE);
+			dma_unmap_single(dev, dma_private->ld_buf_phys,
+					 sizeof(dma_private->link),
+					 DMA_TO_DEVICE);
 		}
 
 		/* Deallocate the fsl_dma_private structure */
-		dma_free_coherent(substream->pcm->card->dev,
-			sizeof(struct fsl_dma_private),
-			dma_private, dma_private->ld_buf_phys);
+		dma_free_coherent(dev, sizeof(struct fsl_dma_private),
+				  dma_private, dma_private->ld_buf_phys);
 		substream->runtime->private_data = NULL;
 	}
 
-	dma_global_data.assigned[dir] = 0;
+	dma->assigned = 0;
 
 	return 0;
 }
@@ -814,6 +795,40 @@ static void fsl_dma_free_dma_buffers(struct snd_pcm *pcm)
 	}
 }
 
+/* List of DMA nodes that we've probed */
+static LIST_HEAD(dma_list);
+
+/**
+ * find_ssi_node -- returns the SSI node that points to his DMA channel node
+ *
+ * Although this DMA driver attempts to operate independently of the other
+ * devices, it still needs to determine some information about the SSI device
+ * that it's working with.  Unfortunately, the device tree does not contain
+ * a pointer from the DMA channel node to the SSI node -- the pointer goes the
+ * other way.  So we need to scan the device tree for SSI nodes until we find
+ * the one that points to the given DMA channel node.  It's ugly, but at least
+ * it's contained in this one function.
+ */
+static struct device_node *find_ssi_node(struct device_node *dma_channel_np)
+{
+	struct device_node *ssi_np, *np;
+
+	for_each_compatible_node(ssi_np, NULL, "fsl,mpc8610-ssi") {
+		/* Check each DMA phandle to see if it points to us.  We
+		 * assume that device_node pointers are a valid comparison.
+		 */
+		np = of_parse_phandle(ssi_np, "fsl,playback-dma", 0);
+		if (np == dma_channel_np)
+			return ssi_np;
+
+		np = of_parse_phandle(ssi_np, "fsl,capture-dma", 0);
+		if (np == dma_channel_np)
+			return ssi_np;
+	}
+
+	return NULL;
+}
+
 static struct snd_pcm_ops fsl_dma_ops = {
 	.open   	= fsl_dma_open,
 	.close  	= fsl_dma_close,
@@ -823,59 +838,112 @@ static struct snd_pcm_ops fsl_dma_ops = {
 	.pointer	= fsl_dma_pointer,
 };
 
-struct snd_soc_platform fsl_soc_platform = {
-	.name   	= "fsl-dma",
-	.pcm_ops	= &fsl_dma_ops,
-	.pcm_new	= fsl_dma_new,
-	.pcm_free       = fsl_dma_free_dma_buffers,
-};
-EXPORT_SYMBOL_GPL(fsl_soc_platform);
+static int __devinit fsl_soc_dma_probe(struct of_device *of_dev,
+				       const struct of_device_id *match)
+ {
+	struct dma_object *dma;
+	struct device_node *np = of_dev->dev.of_node;
+	struct device_node *ssi_np;
+	struct resource res;
+	int ret;
 
-/**
- * fsl_dma_configure: store the DMA parameters from the fabric driver.
- *
- * This function is called by the ASoC fabric driver to give us the DMA and
- * SSI channel information.
- *
- * Unfortunately, ASoC V1 does make it possible to determine the DMA/SSI
- * data when a substream is created, so for now we need to store this data
- * into a global variable.  This means that we can only support one DMA
- * controller, and hence only one SSI.
- */
-int fsl_dma_configure(struct fsl_dma_info *dma_info)
+	/* Find the SSI node that points to us. */
+	ssi_np = find_ssi_node(np);
+	if (!ssi_np) {
+		dev_err(&of_dev->dev, "cannot find parent SSI node\n");
+		return -ENODEV;
+	}
+
+	ret = of_address_to_resource(ssi_np, 0, &res);
+	of_node_put(ssi_np);
+	if (ret) {
+		dev_err(&of_dev->dev, "could not determine device resources\n");
+		return ret;
+	}
+
+	dma = kzalloc(sizeof(*dma) + strlen(np->full_name), GFP_KERNEL);
+	if (!dma) {
+		dev_err(&of_dev->dev, "could not allocate dma object\n");
+		return -ENOMEM;
+	}
+
+	strcpy(dma->path, np->full_name);
+	dma->dai.ops = &fsl_dma_ops;
+	dma->dai.pcm_new = fsl_dma_new;
+	dma->dai.pcm_free = fsl_dma_free_dma_buffers;
+
+	/* Store the SSI-specific information that we need */
+	dma->ssi_stx_phys = res.start + offsetof(struct ccsr_ssi, stx0);
+	dma->ssi_srx_phys = res.start + offsetof(struct ccsr_ssi, srx0);
+
+	ret = snd_soc_register_platform(&of_dev->dev, &dma->dai);
+	if (ret) {
+		dev_err(&of_dev->dev, "could not register platform\n");
+		kfree(dma);
+		return ret;
+	}
+
+	dma->channel = of_iomap(np, 0);
+	dma->irq = irq_of_parse_and_map(np, 0);
+	list_add(&dma->list, &dma_list);
+
+	return 0;
+}
+
+static int __devexit fsl_soc_dma_remove(struct of_device *of_dev)
 {
-	static int initialized;
+	struct list_head *n, *ptr;
+	struct dma_object *dma;
 
-	/* We only support one DMA controller for now */
-	if (initialized)
-		return 0;
+	list_for_each_safe(ptr, n, &dma_list) {
+		dma = list_entry(ptr, struct dma_object, list);
+		list_del_init(ptr);
+
+		snd_soc_unregister_platform(&of_dev->dev);
+		iounmap(dma->channel);
+		irq_dispose_mapping(dma->irq);
+		kfree(dma);
+	}
 
-	dma_global_data.ssi_stx_phys = dma_info->ssi_stx_phys;
-	dma_global_data.ssi_srx_phys = dma_info->ssi_srx_phys;
-	dma_global_data.dma_channel[0] = dma_info->dma_channel[0];
-	dma_global_data.dma_channel[1] = dma_info->dma_channel[1];
-	dma_global_data.irq[0] = dma_info->dma_irq[0];
-	dma_global_data.irq[1] = dma_info->dma_irq[1];
-	dma_global_data.assigned[0] = 0;
-	dma_global_data.assigned[1] = 0;
-
-	initialized = 1;
-	return 1;
+	return 0;
 }
-EXPORT_SYMBOL_GPL(fsl_dma_configure);
 
-static int __init fsl_soc_platform_init(void)
+static const struct of_device_id fsl_soc_dma_ids[] = {
+	{ .compatible = "fsl,ssi-dma-channel", },
+	{}
+};
+MODULE_DEVICE_TABLE(of, fsl_soc_dma_ids);
+
+static struct of_platform_driver fsl_soc_dma_driver = {
+	.driver = {
+		.name = "fsl-pcm-audio",
+		.owner = THIS_MODULE,
+		.of_match_table = fsl_soc_dma_ids,
+	},
+	.probe = fsl_soc_dma_probe,
+	.remove = __devexit_p(fsl_soc_dma_remove),
+};
+
+static int __init fsl_soc_dma_init(void)
 {
-	return snd_soc_register_platform(&fsl_soc_platform);
+	pr_info("Freescale Elo DMA ASoC PCM Driver\n");
+
+	return of_register_platform_driver(&fsl_soc_dma_driver);
 }
-module_init(fsl_soc_platform_init);
 
-static void __exit fsl_soc_platform_exit(void)
+static void __exit fsl_soc_dma_exit(void)
 {
-	snd_soc_unregister_platform(&fsl_soc_platform);
+	of_unregister_platform_driver(&fsl_soc_dma_driver);
 }
-module_exit(fsl_soc_platform_exit);
+
+/* We want the DMA driver to be initialized before the SSI driver, so that
+ * when the SSI driver calls fsl_soc_dma_dai_from_node(), the DMA driver
+ * will already have been probed.  The easiest way to do that is to make the
+ * __init function called via arch_initcall().
+ */
+module_init(fsl_soc_dma_init);
+module_exit(fsl_soc_dma_exit);
 
 MODULE_AUTHOR("Timur Tabi <timur@freescale.com>");
-MODULE_DESCRIPTION("Freescale Elo DMA ASoC PCM module");
-MODULE_LICENSE("GPL");
+MODULE_DESCRIPTION("Freescale Elo DMA ASoC PCM Driver");
+MODULE_LICENSE("GPL v2");