Eric Lee / smarc-ti-linux-kernel

Download as
Browse Code ยป

Commit f4eb010706b6c96c136c7aaa9079159743f33fa8

Authored by Michael Ellerman
Committed by Paul Mackerras
1 parent 58119068cb
Exists in master and in 20 other branches dlt-processor-sdk-linux-03.00.00.04, newt-ti-linux-3.12.y, processor-sdk-linux-01.00.00, processor-sdk-linux-02.00.01, smarc-ti-linux-3.12.10, smarc-ti-linux-3.12.y, smarc-ti-linux-3.14.y, smarc-ti-linux-3.15.y, smarc-ti-lsk-linux-4.1.y, smarct3x-processor-sdk-04.01.00.06, smarct3x-processor-sdk-linux-02.00.01, smarct3x-processor-sdk-linux-03.00.00.04, smarct4x-800-processor-sdk-linux-02.00.01, smarct4x-processor-sdk-04.01.00.06, smarct4x-processor-sdk-linux-02.00.01, smarct4x-processor-sdk-linux-03.00.00.04, ti-linux-3.12.y, ti-linux-3.14.y, ti-linux-3.15.y, ti-lsk-linux-4.1.y

[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>

Showing 2 changed files with 26 additions and 0 deletions Side-by-side Diff

... ... @@ -138,6 +138,31 @@
138 138 EXPORT_SYMBOL(of_get_parent);
139 139  
140 140 /**
  141 + * of_get_next_parent - Iterate to a node's parent
  142 + * @node: Node to get parent of
  143 + *
  144 + * This is like of_get_parent() except that it drops the
  145 + * refcount on the passed node, making it suitable for iterating
  146 + * through a node's parents.
  147 + *
  148 + * Returns a node pointer with refcount incremented, use
  149 + * of_node_put() on it when done.
  150 + */
  151 +struct device_node *of_get_next_parent(struct device_node *node)
  152 +{
  153 + struct device_node *parent;
  154 +
  155 + if (!node)
  156 + return NULL;
  157 +
  158 + read_lock(&devtree_lock);
  159 + parent = of_node_get(node->parent);
  160 + of_node_put(node);
  161 + read_unlock(&devtree_lock);
  162 + return parent;
  163 +}
  164 +
  165 +/**
141 166 * of_get_next_child - Iterate a node childs
142 167 * @node: parent node
143 168 * @prev: previous child of the parent node, or NULL to get first
... ... @@ -50,6 +50,7 @@
50 50 extern struct device_node *of_find_node_by_path(const char *path);
51 51 extern struct device_node *of_find_node_by_phandle(phandle handle);
52 52 extern struct device_node *of_get_parent(const struct device_node *node);
  53 +extern struct device_node *of_get_next_parent(struct device_node *node);
53 54 extern struct device_node *of_get_next_child(const struct device_node *node,
54 55 struct device_node *prev);
55 56 #define for_each_child_of_node(parent, child) \