ASoC: dmaengine_pcm: Add support for compat platforms

Add support for platforms which don't use devicetree yet or have to optionally
support a non-devicetree way to request the DMA channel. The patch adds the
compat_request_channel and compat_filter_fn callbacks to the
snd_dmaengine_pcm_config struct. If the compat_request_channel is implemented it
will be used to request the DMA channel. If not dma_request_channel with
compat_filter_fn as the filter function will be used to request the channel.

The patch also exports the snd_dmaengine_pcm_request_chan() function, since
compat platforms will want to use it to request their DMA channel.

Signed-off-by: Lars-Peter Clausen <lars@metafoo.de>
Tested-by: Stephen Warren <swarren@nvidia.com>
Tested-by: Shawn Guo <shawn.guo@linaro.org>
Signed-off-by: Mark Brown <broonie@opensource.wolfsonmicro.com>

1 files changed, 12 insertions, 2 deletions

diff --git a/sound/soc/soc-dmaengine-pcm.c b/sound/soc/soc-dmaengine-pcm.c
index b0420a75f41..aa924d9b798 100644
--- a/sound/soc/soc-dmaengine-pcm.c
+++ b/sound/soc/soc-dmaengine-pcm.c
@@ -254,7 +254,16 @@ snd_pcm_uframes_t snd_dmaengine_pcm_pointer(struct snd_pcm_substream *substream)
 }
 EXPORT_SYMBOL_GPL(snd_dmaengine_pcm_pointer);
 
-static struct dma_chan *dmaengine_pcm_request_channel(dma_filter_fn filter_fn,
+/**
+ * snd_dmaengine_pcm_request_channel - Request channel for the dmaengine PCM
+ * @filter_fn: Filter function used to request the DMA channel
+ * @filter_data: Data passed to the DMA filter function
+ *
+ * Returns NULL or the requested DMA channel.
+ *
+ * This function request a DMA channel for usage with dmaengine PCM.
+ */
+struct dma_chan *snd_dmaengine_pcm_request_channel(dma_filter_fn filter_fn,
 	void *filter_data)
 {
 	dma_cap_mask_t mask;
@@ -265,6 +274,7 @@ static struct dma_chan *dmaengine_pcm_request_channel(dma_filter_fn filter_fn,
 
 	return dma_request_channel(mask, filter_fn, filter_data);
 }
+EXPORT_SYMBOL_GPL(snd_dmaengine_pcm_request_channel);
 
 /**
  * snd_dmaengine_pcm_open - Open a dmaengine based PCM substream
@@ -320,7 +330,7 @@ int snd_dmaengine_pcm_open_request_chan(struct snd_pcm_substream *substream,
 	dma_filter_fn filter_fn, void *filter_data)
 {
 	return snd_dmaengine_pcm_open(substream,
-		    dmaengine_pcm_request_channel(filter_fn, filter_data));
+		    snd_dmaengine_pcm_request_channel(filter_fn, filter_data));
 }
 EXPORT_SYMBOL_GPL(snd_dmaengine_pcm_open_request_chan);