[PATCH v4 08/16] device property: Introduce fwnode_find_reference()

Heikki Krogerus
2019-05-22T10:51:37Z

In most cases the references that the drivers look for don't
have any arguments. This introduces a wrapper function for
fwnode_property_get_reference_args() that looks for
references by using only the name and index.

Signed-off-by: Heikki Krogerus <heikki.krogerus@linux.intel.com>
---
drivers/base/property.c | 24 ++++++++++++++++++++++++
include/linux/property.h | 4 ++++
2 files changed, 28 insertions(+)

diff --git a/drivers/base/property.c b/drivers/base/property.c
index 348b37e64944..81bd01ed4042 100644
--- a/drivers/base/property.c
+++ b/drivers/base/property.c
@@ -484,6 +484,30 @@ int fwnode_property_get_reference_args(const struct fwnode_handle *fwnode,
}
EXPORT_SYMBOL_GPL(fwnode_property_get_reference_args);

+/**
+ * fwnode_find_reference - Find named reference to a fwnode_handle
+ * @fwnode: Firmware node where to look for the reference
+ * @name: The name of the reference
+ * @index: Index of the reference
+ *
+ * @index can be used when the named reference holds a table of references.
+ *
+ * Returns pointer to the reference fwnode, or ERR_PTR. Caller is responsible to
+ * call fwnode_handle_put() on the returned fwnode pointer.
+ */
+struct fwnode_handle *fwnode_find_reference(const struct fwnode_handle *fwnode,
+ const char *name,
+ unsigned int index)
+{
+ struct fwnode_reference_args args;
+ int ret;
+
+ ret = fwnode_property_get_reference_args(fwnode, name, NULL, 0, index,
+ &args);
+ return ret ? ERR_PTR(ret) : args.fwnode;
+}
+EXPORT_SYMBOL_GPL(fwnode_find_reference);
+
/**
* device_remove_properties - Remove properties from a device object.
* @dev: Device whose properties to remove.
diff --git a/include/linux/property.h b/include/linux/property.h
index abcde2f236a0..088d4db7e949 100644
--- a/include/linux/property.h
+++ b/include/linux/property.h
@@ -79,6 +79,10 @@ int fwnode_property_get_reference_args(const struct fwnode_handle *fwnode,
unsigned int nargs, unsigned int index,
struct fwnode_reference_args *args);

+struct fwnode_handle *fwnode_find_reference(const struct fwnode_handle *fwnode,
+ const char *name,
+ unsigned int index);
+
struct fwnode_handle *fwnode_get_parent(const struct fwnode_handle *fwnode);
struct fwnode_handle *fwnode_get_next_parent(
struct fwnode_handle *fwnode);
--
2.20.1