Merge branch 'for-3.14/deps-from-dma-defer_probe' into for-3.14/dmas-resets-rework

This merges git://git.infradead.org/users/vkoul/slave-dma.git topic/defer_probe

1 files changed, 31 insertions, 4 deletions

diff --git a/drivers/dma/dmaengine.c b/drivers/dma/dmaengine.c
index ea806bdc12ef..e17e9b22d85e 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);