of: add of_parse_phandle() helper for parsing phandle properties

of_parse_phandle() is a helper function to read and parse a phandle
property and return a pointer to the resulting device_node.

Signed-off-by: Grant Likely <grant.likely@secretlab.ca>
Acked-by: Andy Fleming <afleming@freescale.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
This commit is contained in:
Grant Likely 2009-04-25 12:52:40 +00:00 committed by David S. Miller
parent edf391ff17
commit 739649c53d
2 changed files with 27 additions and 0 deletions

View file

@ -494,6 +494,30 @@ int of_modalias_node(struct device_node *node, char *modalias, int len)
}
EXPORT_SYMBOL_GPL(of_modalias_node);
/**
* of_parse_phandle - Resolve a phandle property to a device_node pointer
* @np: Pointer to device node holding phandle property
* @phandle_name: Name of property holding a phandle value
* @index: For properties holding a table of phandles, this is the index into
* the table
*
* Returns the device_node pointer with refcount incremented. Use
* of_node_put() on it when done.
*/
struct device_node *
of_parse_phandle(struct device_node *np, const char *phandle_name, int index)
{
const phandle *phandle;
int size;
phandle = of_get_property(np, phandle_name, &size);
if ((!phandle) || (size < sizeof(*phandle) * (index + 1)))
return NULL;
return of_find_node_by_phandle(phandle[index]);
}
EXPORT_SYMBOL(of_parse_phandle);
/**
* of_parse_phandles_with_args - Find a node pointed by phandle in a list
* @np: pointer to a device tree node containing a list

View file

@ -77,6 +77,9 @@ extern int of_n_size_cells(struct device_node *np);
extern const struct of_device_id *of_match_node(
const struct of_device_id *matches, const struct device_node *node);
extern int of_modalias_node(struct device_node *node, char *modalias, int len);
extern struct device_node *of_parse_phandle(struct device_node *np,
const char *phandle_name,
int index);
extern int of_parse_phandles_with_args(struct device_node *np,
const char *list_name, const char *cells_name, int index,
struct device_node **out_node, const void **out_args);