i2c: acpi: Factor out getting the IRQ from ACPI

In preparation for future refactoring factor out the fetch of the IRQ
into its own helper function. Whilst we are at it update the handling
to return the actual error code returned from acpi_dev_get_resources
as well.
Reviewed-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
Signed-off-by: Charles Keepax <ckeepax@opensource.cirrus.com>
Reviewed-by: Mika Westerberg <mika.westerberg@linux.intel.com>
Signed-off-by: Wolfram Sang <wsa@the-dreams.de>

drivers/i2c/i2c-core-acpi.c

@@ -148,12 +148,29 @@ static int i2c_acpi_add_resource(struct acpi_resource *ares, void *data)
 	return 1; /* No need to add resource to the list */
 }
 
+static int i2c_acpi_get_irq(struct acpi_device *adev)
+{
+	struct list_head resource_list;
+	int irq = -ENOENT;
+	int ret;
+
+	INIT_LIST_HEAD(&resource_list);
+
+	ret = acpi_dev_get_resources(adev, &resource_list,
+				     i2c_acpi_add_resource, &irq);
+	if (ret < 0)
+		return ret;
+
+	acpi_dev_free_resource_list(&resource_list);
+
+	return irq;
+}
+
 static int i2c_acpi_get_info(struct acpi_device *adev,
 			     struct i2c_board_info *info,
 			     struct i2c_adapter *adapter,
 			     acpi_handle *adapter_handle)
 {
-	struct list_head resource_list;
 	struct i2c_acpi_lookup lookup;
 	int ret;
 
@@ -185,13 +202,9 @@ static int i2c_acpi_get_info(struct acpi_device *adev,
 		*adapter_handle = lookup.adapter_handle;
 
 	/* Then fill IRQ number if any */
-	INIT_LIST_HEAD(&resource_list);
-	ret = acpi_dev_get_resources(adev, &resource_list,
-				     i2c_acpi_add_resource, &info->irq);
-	if (ret < 0)
-		return -EINVAL;
-
-	acpi_dev_free_resource_list(&resource_list);
+	info->irq = i2c_acpi_get_irq(adev);
+	if (info->irq < 0)
+		return info->irq;
 
 	acpi_set_modalias(adev, dev_name(&adev->dev), info->type,
 			  sizeof(info->type));