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authorMichael Ellerman <michael@ellerman.id.au>2007-10-26 16:54:31 +1000
committerPaul Mackerras <paulus@samba.org>2008-02-06 16:29:59 +1100
commitf4eb010706b6c96c136c7aaa9079159743f33fa8 (patch)
tree53be8d89ad0073f90b2975e780c0426249ee3f3e /drivers/of
parent58119068cb27ef7513f80aff44b62a3a8f40ef5f (diff)
downloadop-kernel-dev-f4eb010706b6c96c136c7aaa9079159743f33fa8.zip
op-kernel-dev-f4eb010706b6c96c136c7aaa9079159743f33fa8.tar.gz
[POWERPC] Add of_get_next_parent()
Iterating through a device node's parents is simple enough, but dealing with the refcounts properly is a little ugly, and replicating that logic is asking for someone to get it wrong or forget it all together, eg: while (dn != NULL) { /* loop body */ tmp = of_get_parent(dn); of_node_put(dn); dn = tmp; } So add of_get_next_parent(), inspired by of_get_next_child(). The contract is that it returns the parent and drops the reference on the current node, this makes the loop look like: while (dn != NULL) { /* loop body */ dn = of_get_next_parent(dn); } Signed-off-by: Michael Ellerman <michael@ellerman.id.au> Acked-by: David S. Miller <davem@davemloft.net> Signed-off-by: Paul Mackerras <paulus@samba.org>
Diffstat (limited to 'drivers/of')
-rw-r--r--drivers/of/base.c25
1 files changed, 25 insertions, 0 deletions
diff --git a/drivers/of/base.c b/drivers/of/base.c
index b306fef..80c9dec 100644
--- a/drivers/of/base.c
+++ b/drivers/of/base.c
@@ -138,6 +138,31 @@ struct device_node *of_get_parent(const struct device_node *node)
EXPORT_SYMBOL(of_get_parent);
/**
+ * of_get_next_parent - Iterate to a node's parent
+ * @node: Node to get parent of
+ *
+ * This is like of_get_parent() except that it drops the
+ * refcount on the passed node, making it suitable for iterating
+ * through a node's parents.
+ *
+ * Returns a node pointer with refcount incremented, use
+ * of_node_put() on it when done.
+ */
+struct device_node *of_get_next_parent(struct device_node *node)
+{
+ struct device_node *parent;
+
+ if (!node)
+ return NULL;
+
+ read_lock(&devtree_lock);
+ parent = of_node_get(node->parent);
+ of_node_put(node);
+ read_unlock(&devtree_lock);
+ return parent;
+}
+
+/**
* of_get_next_child - Iterate a node childs
* @node: parent node
* @prev: previous child of the parent node, or NULL to get first
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