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of: Add helpers for finding device nodes which have a given property 

This commit adds a routine for finding a device node which has a
certain property.  The contents of the property are not taken into
account, merely the presence or absence of the property.

Based on that routine, we add a for_each_ macro for iterating over all
nodes that have a certain property.

Signed-off-by: Michael Ellerman <michael@ellerman.id.au>
Signed-off-by: Paul Mackerras <paulus@samba.org>
This commit is contained in:
Michael Ellerman 2008-11-12 18:54:42 +00:00 committed by Paul Mackerras
parent ae564c63b8
commit 1e291b14c8
2 changed files with 41 additions and 0 deletions
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35
drivers/of/base.c
View File

@ -328,6 +328,41 @@ struct device_node *of_find_compatible_node(struct device_node *from,
}
EXPORT_SYMBOL(of_find_compatible_node);
/**
* of_find_node_with_property - Find a node which has a property with
* the given name.
* @from: The node to start searching from or NULL, the node
* you pass will not be searched, only the next one
* will; typically, you pass what the previous call
* returned. of_node_put() will be called on it
* @prop_name: The name of the property to look for.
*
* Returns a node pointer with refcount incremented, use
* of_node_put() on it when done.
*/
struct device_node *of_find_node_with_property(struct device_node *from,
const char *prop_name)
{
struct device_node *np;
struct property *pp;
read_lock(&devtree_lock);
np = from ? from->allnext : allnodes;
for (; np; np = np->allnext) {
for (pp = np->properties; pp != 0; pp = pp->next) {
if (of_prop_cmp(pp->name, prop_name) == 0) {
of_node_get(np);
goto out;
}
}
}
out:
of_node_put(from);
read_unlock(&devtree_lock);
return np;
}
EXPORT_SYMBOL(of_find_node_with_property);
/**
* of_match_node - Tell if an device_node has a matching of_match structure
* @matches: array of of device match structures to search in

6
include/linux/of.h
View File

@ -57,6 +57,12 @@ extern struct device_node *of_get_next_child(const struct device_node *node,
for (child = of_get_next_child(parent, NULL); child != NULL; \
child = of_get_next_child(parent, child))
extern struct device_node *of_find_node_with_property(
struct device_node *from, const char *prop_name);
#define for_each_node_with_property(dn, prop_name) \
for (dn = of_find_node_with_property(NULL, prop_name); dn; \
dn = of_find_node_with_property(dn, prop_name))
extern struct property *of_find_property(const struct device_node *np,
const char *name,
int *lenp);