Merge remote-tracking branch 'asoc/topic/dma' into asoc-next

1 files changed, 31 insertions, 4 deletions

diff --git a/drivers/dma/dmaengine.c b/drivers/dma/dmaengine.c
index ef63b9058f3c..92caad629d99 100644
--- a/drivers/dma/dmaengine.c
+++ b/drivers/dma/dmaengine.c
@@ -540,6 +540,8 @@ EXPORT_SYMBOL_GPL(dma_get_slave_channel);
  * @mask: capabilities that the channel must satisfy
  * @fn: optional callback to disposition available channels
  * @fn_param: opaque parameter to pass to dma_filter_fn
+ *
+ * Returns pointer to appropriate DMA channel on success or NULL.
  */
 struct dma_chan *__dma_request_channel(const dma_cap_mask_t *mask,
 				       dma_filter_fn fn, void *fn_param)
@@ -591,18 +593,43 @@ EXPORT_SYMBOL_GPL(__dma_request_channel);
  * dma_request_slave_channel - try to allocate an exclusive slave channel
  * @dev:	pointer to client device structure
  * @name:	slave channel name
+ *
+ * Returns pointer to appropriate DMA channel on success or an error pointer.
  */
-struct dma_chan *dma_request_slave_channel(struct device *dev, const char *name)
+struct dma_chan *dma_request_slave_channel_reason(struct device *dev,
+						  const char *name)
 {
+	struct dma_chan *chan;
+
 	/* If device-tree is present get slave info from here */
 	if (dev->of_node)
 		return of_dma_request_slave_channel(dev->of_node, name);
 
 	/* If device was enumerated by ACPI get slave info from here */
-	if (ACPI_HANDLE(dev))
-		return acpi_dma_request_slave_chan_by_name(dev, name);
+	if (ACPI_HANDLE(dev)) {
+		chan = acpi_dma_request_slave_chan_by_name(dev, name);
+		if (chan)
+			return chan;
+	}
 
-	return NULL;
+	return ERR_PTR(-ENODEV);
+}
+EXPORT_SYMBOL_GPL(dma_request_slave_channel_reason);
+
+/**
+ * dma_request_slave_channel - try to allocate an exclusive slave channel
+ * @dev:	pointer to client device structure
+ * @name:	slave channel name
+ *
+ * Returns pointer to appropriate DMA channel on success or NULL.
+ */
+struct dma_chan *dma_request_slave_channel(struct device *dev,
+					   const char *name)
+{
+	struct dma_chan *ch = dma_request_slave_channel_reason(dev, name);
+	if (IS_ERR(ch))
+		return NULL;
+	return ch;
 }
 EXPORT_SYMBOL_GPL(dma_request_slave_channel);