@@ -43,6 +43,8 @@ snd_pcm_uframes_t snd_dmaengine_pcm_pointer_no_residue(struct snd_pcm_substream
int snd_dmaengine_pcm_open(struct snd_pcm_substream *substream,
dma_filter_fn filter_fn, void *filter_data);
+int snd_dmaengine_generic_pcm_open(struct snd_pcm_substream *substream,
+ struct device *dev, const char *name);
int snd_dmaengine_pcm_close(struct snd_pcm_substream *substream);
struct dma_chan *snd_dmaengine_pcm_get_chan(struct snd_pcm_substream *substream);
@@ -304,6 +304,45 @@ int snd_dmaengine_pcm_open(struct snd_pcm_substream *substream,
EXPORT_SYMBOL_GPL(snd_dmaengine_pcm_open);
/**
+ * snd_dmaengine_generic_pcm_open - Open a dmaengine based PCM substream
+ * @substream: PCM substream
+ * @dev: pointer to DMA client device structure
+ * @name: DMA slave channel name
+ *
+ * Returns 0 on success, a negative error code otherwise.
+ *
+ * This function is a variant of snd_dmaengine_pcm_open(). It takes different
+ * parameters and calls generic DMA helper dma_request_slave_channel() to
+ * request a DMA channel from dmaengine.
+ */
+int snd_dmaengine_generic_pcm_open(struct snd_pcm_substream *substream,
+ struct device *dev, const char *name)
+{
+ struct dmaengine_pcm_runtime_data *prtd;
+ int ret;
+
+ ret = snd_pcm_hw_constraint_integer(substream->runtime,
+ SNDRV_PCM_HW_PARAM_PERIODS);
+ if (ret < 0)
+ return ret;
+
+ prtd = kzalloc(sizeof(*prtd), GFP_KERNEL);
+ if (!prtd)
+ return -ENOMEM;
+
+ prtd->dma_chan = dma_request_slave_channel(dev, name);
+ if (!prtd->dma_chan) {
+ kfree(prtd);
+ return -ENXIO;
+ }
+
+ substream->runtime->private_data = prtd;
+
+ return 0;
+}
+EXPORT_SYMBOL_GPL(snd_dmaengine_generic_pcm_open);
+
+/**
* snd_dmaengine_pcm_close - Close a dmaengine based PCM substream
* @substream: PCM substream
*/
With generic DMA device tree binding and helper function dma_request_slave_channel() in place, dmaengine_pcm should support that in requesting DMA channel for users that support generic DMA device tree binding. Add a new API snd_dmaengine_generic_pcm_open() as the variant of snd_dmaengine_pcm_open(). It takes DMA client struct device pointer and slave channel name as arguments and calls generic DMA helper dma_request_slave_channel() to request DMA channel from dmaengine. Signed-off-by: Shawn Guo <shawn.guo@linaro.org> Cc: Mark Brown <broonie@opensource.wolfsonmicro.com> Cc: alsa-devel@alsa-project.org --- Mark, Please maintain a topic branch for the patch if it looks good to you. It should be useful for any dmaengine_pcm user that is moving to generic DMA device tree binding. Thanks, Shawn include/sound/dmaengine_pcm.h | 2 ++ sound/soc/soc-dmaengine-pcm.c | 39 +++++++++++++++++++++++++++++++++++++++ 2 files changed, 41 insertions(+)