device property: Add fwnode_get_parent()

Now that ACPI has support for returning parent firmware node for both types
of nodes we can expose this to others as well. This adds a new function
fwnode_get_parent() that can be used for DT and ACPI nodes to retrieve the
parent firmware node.

Signed-off-by: Mika Westerberg <mika.westerberg@linux.intel.com>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>

2 files changed, 27 insertions, 0 deletions

diff --git a/drivers/base/property.c b/drivers/base/property.c
index c458c63e353f..a25233430d18 100644
--- a/drivers/base/property.c
+++ b/drivers/base/property.c
@@ -932,6 +932,31 @@ int device_add_properties(struct device *dev,
 EXPORT_SYMBOL_GPL(device_add_properties);
 
 /**
+ * fwnode_get_parent - Return parent firwmare node
+ * @fwnode: Firmware whose parent is retrieved
+ *
+ * Return parent firmware node of the given node if possible or %NULL if no
+ * parent was available.
+ */
+struct fwnode_handle *fwnode_get_parent(struct fwnode_handle *fwnode)
+{
+	struct fwnode_handle *parent = NULL;
+
+	if (is_of_node(fwnode)) {
+		struct device_node *node;
+
+		node = of_get_parent(to_of_node(fwnode));
+		if (node)
+			parent = &node->fwnode;
+	} else if (is_acpi_node(fwnode)) {
+		parent = acpi_node_get_parent(fwnode);
+	}
+
+	return parent;
+}
+EXPORT_SYMBOL_GPL(fwnode_get_parent);
+
+/**
  * device_get_next_child_node - Return the next child node handle for a device
  * @dev: Device to find the next child node for.
  * @child: Handle to one of the device's child nodes or a null handle.
diff --git a/include/linux/property.h b/include/linux/property.h
index 64e3a9c6d95f..ab0a8160cef6 100644
--- a/include/linux/property.h
+++ b/include/linux/property.h
@@ -70,6 +70,8 @@ int fwnode_property_read_string(struct fwnode_handle *fwnode,
 int fwnode_property_match_string(struct fwnode_handle *fwnode,
 				 const char *propname, const char *string);
 
+struct fwnode_handle *fwnode_get_parent(struct fwnode_handle *fwnode);
+
 struct fwnode_handle *device_get_next_child_node(struct device *dev,
 						 struct fwnode_handle *child);