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>

diff --git a/drivers/dma/acpi-dma.c b/drivers/dma/acpi-dma.c
index 1fda371..de361a1 100644 (file)
--- 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);
 }

diff --git a/drivers/dma/dmaengine.c b/drivers/dma/dmaengine.c
index ed610b4..a886713 100644 (file)
--- a/drivers/dma/dmaengine.c
+++ b/drivers/dma/dmaengine.c
@@ -627,18 +627,13 @@ EXPORT_SYMBOL_GPL(__dma_request_channel);
 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)) {
-               chan = acpi_dma_request_slave_chan_by_name(dev, name);
-               if (chan)
-                       return chan;
-       }
+       if (ACPI_HANDLE(dev))
+               return acpi_dma_request_slave_chan_by_name(dev, name);
 
        return ERR_PTR(-ENODEV);
 }

diff --git a/include/linux/acpi_dma.h b/include/linux/acpi_dma.h
index fb02980..329436d 100644 (file)
--- a/include/linux/acpi_dma.h
+++ b/include/linux/acpi_dma.h
@@ -16,6 +16,7 @@
 
 #include <linux/list.h>
 #include <linux/device.h>
+#include <linux/err.h>
 #include <linux/dmaengine.h>
 
 /**
@@ -103,12 +104,12 @@ static inline void devm_acpi_dma_controller_free(struct device *dev)
 static inline struct dma_chan *acpi_dma_request_slave_chan_by_index(
                struct device *dev, size_t index)
 {
-       return NULL;
+       return ERR_PTR(-ENODEV);
 }
 static inline struct dma_chan *acpi_dma_request_slave_chan_by_name(
                struct device *dev, const char *name)
 {
-       return NULL;
+       return ERR_PTR(-ENODEV);
 }
 
 #define acpi_dma_simple_xlate  NULL