Though of_parse_phandle handles lists of phandles, and takes an index parameter, there is no standard way of discovering how many phandles are present on a node. This patch adds a function to count how many phandles are in a phandle list.
Signed-off-by: Mark Rutland <[email protected]> --- drivers/of/base.c | 39 +++++++++++++++++++++++++++++++++++++++ include/linux/of.h | 8 ++++++++ 2 files changed, 47 insertions(+), 0 deletions(-) diff --git a/drivers/of/base.c b/drivers/of/base.c index af3b22a..30ae562 100644 --- a/drivers/of/base.c +++ b/drivers/of/base.c @@ -884,6 +884,45 @@ int of_property_count_strings(struct device_node *np, const char *propname) EXPORT_SYMBOL_GPL(of_property_count_strings); /** + * of_property_count_phandles - find and return the number of phandles from a + * multiple phandles property. + * @np: device node from which the property value is to be read. + * @propname: name of the property to be searched. + * + * Search for a property in a device tree node and retrieve the number of + * phandles contained in it. Returns the number of phandles on success, -ENOENT + * if the property does not exist, -ENODATA if there are no phandles, and + * -EINVAL if the property is not correctly sized for an array of phandles. + */ +int of_property_count_phandles(struct device_node *np, const char *propname) +{ + int size, count, i; + const __be32 *phandle; + + phandle = of_get_property(np, propname, &size); + + if (!phandle) + return -ENOENT; + if (size == 0) + return -ENODATA; + if (size % (sizeof *phandle)) + return -EINVAL; + + count = size / (sizeof(*phandle)); + + /* Check the phandle targets actually exist */ + for (i = 0; i < count; i++) { + struct device_node *node = of_parse_phandle(np, propname, i); + if (!node) + return -EINVAL; + of_node_put(node); + } + + return count; +} +EXPORT_SYMBOL_GPL(of_property_count_phandles); + +/** * 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 diff --git a/include/linux/of.h b/include/linux/of.h index b4e50d5..1f03f46 100644 --- a/include/linux/of.h +++ b/include/linux/of.h @@ -258,6 +258,8 @@ 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_property_count_phandles(struct device_node *np, + const char *propname); extern int of_parse_phandle_with_args(struct device_node *np, const char *list_name, const char *cells_name, int index, struct of_phandle_args *out_args); @@ -411,6 +413,12 @@ static inline int of_property_match_string(struct device_node *np, return -ENOSYS; } +static inline int of_property_count_phandles(struct device_node *np, + const char *propname) +{ + return -ENOSYS; +} + static inline struct device_node *of_parse_phandle(struct device_node *np, const char *phandle_name, int index) -- 1.7.0.4 _______________________________________________ devicetree-discuss mailing list [email protected] https://lists.ozlabs.org/listinfo/devicetree-discuss
