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Commit f4eb0107 authored by Michael Ellerman's avatar Michael Ellerman Committed by Paul Mackerras
Browse files

[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: default avatarMichael Ellerman <michael@ellerman.id.au>
Acked-by: default avatarDavid S. Miller <davem@davemloft.net>
Signed-off-by: default avatarPaul Mackerras <paulus@samba.org>
parent 58119068

drivers/of/base.c

+25 −0
Original line number Diff line number Diff line
@@ -137,6 +137,31 @@ 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

include/linux/of.h

+1 −0
Original line number Diff line number Diff line
@@ -50,6 +50,7 @@ extern struct device_node *of_find_matching_node(struct device_node *from, 
extern struct device_node *of_find_node_by_path(const char *path);

extern struct device_node *of_find_node_by_phandle(phandle handle);

extern struct device_node *of_get_parent(const struct device_node *node);

extern struct device_node *of_get_next_parent(struct device_node *node);

extern struct device_node *of_get_next_child(const struct device_node *node,

					     struct device_node *prev);

#define for_each_child_of_node(parent, child) \