[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>
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@ -137,6 +137,31 @@ struct device_node *of_get_parent(const struct device_node *node)
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}
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EXPORT_SYMBOL(of_get_parent);
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/**
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* of_get_next_parent - Iterate to a node's parent
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* @node: Node to get parent of
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*
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* This is like of_get_parent() except that it drops the
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* refcount on the passed node, making it suitable for iterating
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* through a node's parents.
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*
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* Returns a node pointer with refcount incremented, use
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* of_node_put() on it when done.
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*/
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struct device_node *of_get_next_parent(struct device_node *node)
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{
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struct device_node *parent;
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if (!node)
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return NULL;
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read_lock(&devtree_lock);
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parent = of_node_get(node->parent);
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of_node_put(node);
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read_unlock(&devtree_lock);
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return parent;
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}
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/**
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* of_get_next_child - Iterate a node childs
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* @node: parent node
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@ -50,6 +50,7 @@ extern struct device_node *of_find_matching_node(struct device_node *from,
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extern struct device_node *of_find_node_by_path(const char *path);
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extern struct device_node *of_find_node_by_phandle(phandle handle);
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extern struct device_node *of_get_parent(const struct device_node *node);
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extern struct device_node *of_get_next_parent(struct device_node *node);
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extern struct device_node *of_get_next_child(const struct device_node *node,
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struct device_node *prev);
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#define for_each_child_of_node(parent, child) \
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