diff options
author | Michael Ellerman <michael@ellerman.id.au> | 2007-10-26 06:54:31 (GMT) |
---|---|---|
committer | Paul Mackerras <paulus@samba.org> | 2008-02-06 05:29:59 (GMT) |
commit | f4eb010706b6c96c136c7aaa9079159743f33fa8 (patch) | |
tree | 53be8d89ad0073f90b2975e780c0426249ee3f3e | |
parent | 58119068cb27ef7513f80aff44b62a3a8f40ef5f (diff) | |
download | linux-f4eb010706b6c96c136c7aaa9079159743f33fa8.tar.xz |
[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>
-rw-r--r-- | drivers/of/base.c | 25 | ||||
-rw-r--r-- | include/linux/of.h | 1 |
2 files changed, 26 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 diff --git a/include/linux/of.h b/include/linux/of.h index b5f33ef..6981016 100644 --- a/include/linux/of.h +++ b/include/linux/of.h @@ -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) \ |