acpi-dma: convert to return error code when asked for channel

Currently acpi_dma_request_slave_chan_by_index() and
acpi_dma_request_slave_chan_by_name() return only requested channel or NULL.
This patch converts them to return appropriate error code instead of NULL in
case of unsuccessfull request.

Signed-off-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
Acked-by: Mika Westerberg <mika.westerberg@linux.intel.com>
Signed-off-by: Vinod Koul <vinod.koul@intel.com>

1 files changed, 8 insertions, 7 deletions

diff --git a/drivers/dma/acpi-dma.c b/drivers/dma/acpi-dma.c
index 1fda371af4b7..de361a156b34 100644
--- a/drivers/dma/acpi-dma.c
+++ b/drivers/dma/acpi-dma.c
@@ -13,6 +13,7 @@
  */
 
 #include <linux/device.h>
+#include <linux/err.h>
 #include <linux/module.h>
 #include <linux/list.h>
 #include <linux/mutex.h>
@@ -343,7 +344,7 @@ static int acpi_dma_parse_fixed_dma(struct acpi_resource *res, void *data)
  * @index:      index of FixedDMA descriptor for @dev
  *
  * Return:
- * Pointer to appropriate dma channel on success or NULL on error.
+ * Pointer to appropriate dma channel on success or an error pointer.
  */
 struct dma_chan *acpi_dma_request_slave_chan_by_index(struct device *dev,
                 size_t index)
@@ -358,10 +359,10 @@ struct dma_chan *acpi_dma_request_slave_chan_by_index(struct device *dev,
 
         /* Check if the device was enumerated by ACPI */
         if (!dev || !ACPI_HANDLE(dev))
-                return NULL;
+                return ERR_PTR(-ENODEV);
 
         if (acpi_bus_get_device(ACPI_HANDLE(dev), &adev))
-                return NULL;
+                return ERR_PTR(-ENODEV);
 
         memset(&pdata, 0, sizeof(pdata));
         pdata.index = index;
@@ -376,7 +377,7 @@ struct dma_chan *acpi_dma_request_slave_chan_by_index(struct device *dev,
         acpi_dev_free_resource_list(&resource_list);
 
         if (dma_spec->slave_id < 0 || dma_spec->chan_id < 0)
-                return NULL;
+                return ERR_PTR(-ENODEV);
 
         mutex_lock(&acpi_dma_lock);
 
@@ -399,7 +400,7 @@ struct dma_chan *acpi_dma_request_slave_chan_by_index(struct device *dev,
         }
 
         mutex_unlock(&acpi_dma_lock);
-        return chan;
+        return chan ? chan : ERR_PTR(-EPROBE_DEFER);
 }
 EXPORT_SYMBOL_GPL(acpi_dma_request_slave_chan_by_index);
 
@@ -413,7 +414,7 @@ EXPORT_SYMBOL_GPL(acpi_dma_request_slave_chan_by_index);
  * the first FixedDMA descriptor is TX and second is RX.
  *
  * Return:
- * Pointer to appropriate dma channel on success or NULL on error.
+ * Pointer to appropriate dma channel on success or an error pointer.
  */
 struct dma_chan *acpi_dma_request_slave_chan_by_name(struct device *dev,
                 const char *name)
@@ -425,7 +426,7 @@ struct dma_chan *acpi_dma_request_slave_chan_by_name(struct device *dev,
         else if (!strcmp(name, "rx"))
                 index = 1;
         else
-                return NULL;
+                return ERR_PTR(-ENODEV);
 
         return acpi_dma_request_slave_chan_by_index(dev, index);
 }