[PATCH v3 1/4] of: add helpers to get alias from device node path + property name

[Ahmad Fatoum]

The existing of_find_device and of_find_path helpers require that
barebox has already probed devices. For use in code where this
assumption doesn't always hold true, let's add helpers that return
the alias if it exists.

Signed-off-by: Ahmad Fatoum <a.fatoum at pengutronix.de>
---
v2 -> v3:
  - no change
v1 -> v2:
  - fix check for wring variable: rnode = ...; if (!node)
    to if (!rnode)
  - look up property in node at np_name, not in root node
---
 drivers/of/base.c | 57 +++++++++++++++++++++++++++++++++++++++++++++++
 include/of.h      | 32 ++++++++++++++++++++++++++
 2 files changed, 89 insertions(+)

diff --git a/drivers/of/base.c b/drivers/of/base.c
index 4f25f0760a8b..97b2306a75b1 100644
--- a/drivers/of/base.c
+++ b/drivers/of/base.c
@@ -318,6 +318,63 @@ const char *of_alias_get(struct device_node *np)
 }
 EXPORT_SYMBOL_GPL(of_alias_get);
 
+static const char *of_get_partition_device_alias(struct device_node *np)
+{
+	const char *alias;
+
+	alias = of_alias_get(np);
+	if (alias)
+		return alias;
+
+	np = of_get_parent(np);
+	if (np && of_device_is_compatible(np, "fixed-partitions"))
+		np = of_get_parent(np);
+
+	return of_alias_get(np);
+}
+
+const char *of_property_get_alias_from(struct device_node *root,
+				       const char *np_name, const char *propname,
+				       int index)
+{
+	struct device_node *node, *rnode;
+	const char *path;
+	int ret;
+
+	node = of_find_node_by_path_or_alias(root, np_name);
+	if (!node)
+		return NULL;
+
+	ret = of_property_read_string_index(node, propname, index, &path);
+	if (ret < 0)
+		return NULL;
+
+	rnode = of_find_node_by_path(path);
+	if (!rnode)
+		return NULL;
+
+	return of_get_partition_device_alias(rnode);
+}
+EXPORT_SYMBOL_GPL(of_property_get_alias_from);
+
+const char *of_parse_phandle_and_get_alias_from(struct device_node *root,
+						const char *np_name, const char *phandle_name,
+						int index)
+{
+	struct device_node *node, *rnode;
+
+	node = of_find_node_by_path_or_alias(root, np_name);
+	if (!node)
+		return NULL;
+
+	rnode = of_parse_phandle_from(node, root, phandle_name, index);
+	if (!rnode)
+		return NULL;
+
+	return of_get_partition_device_alias(rnode);
+}
+EXPORT_SYMBOL_GPL(of_parse_phandle_and_get_alias_from);
+
 /*
  * of_find_node_by_alias - Find a node given an alias name
  * @root:    the root node of the tree. If NULL, use internal tree
diff --git a/include/of.h b/include/of.h
index 708b3a32556a..04314b769259 100644
--- a/include/of.h
+++ b/include/of.h
@@ -314,6 +314,14 @@ extern int of_alias_get_id_from(struct device_node *root, struct device_node *np
 extern const char *of_alias_get(struct device_node *np);
 extern int of_modalias_node(struct device_node *node, char *modalias, int len);
 
+extern const char *of_property_get_alias_from(struct device_node *root,
+					      const char *np_name, const char *propname,
+					      int index);
+
+extern const char *of_parse_phandle_and_get_alias_from(struct device_node *root,
+						       const char *np_name, const char *phandle_name,
+						       int index);
+
 extern struct device_node *of_get_root_node(void);
 extern int of_set_root_node(struct device_node *node);
 extern int barebox_register_of(struct device_node *root);
@@ -943,6 +951,20 @@ static inline int of_modalias_node(struct device_node *node, char *modalias,
 	return -ENOSYS;
 }
 
+static inline const char *of_property_get_alias_from(struct device_node *root,
+						     const char *np_name, const char *propname,
+						     int index)
+{
+	return NULL;
+}
+
+static inline const char *of_parse_phandle_and_get_alias_from(struct device_node *root,
+							      const char *np_name, const char *phandle_name,
+							      int index)
+{
+	return NULL;
+}
+
 static inline int of_platform_populate(struct device_node *root,
 				const struct of_device_id *matches,
 				struct device *parent)
@@ -1274,6 +1296,16 @@ static inline void of_delete_property_by_name(struct device_node *np, const char
 	of_delete_property(of_find_property(np, name, NULL));
 }
 
+static inline const char *of_property_get_alias(const char *np_name, const char *propname)
+{
+	return of_property_get_alias_from(NULL, np_name, propname, 0);
+}
+
+static inline const char *of_parse_phandle_and_get_alias(const char *np_name, const char *phandle_name)
+{
+	return of_parse_phandle_and_get_alias_from(NULL, np_name, phandle_name, 0);
+}
+
 extern const struct of_device_id of_default_bus_match_table[];
 
 int of_device_enable(struct device_node *node);
-- 
2.39.5