dm: core: add ofnode and dev function to iterate on node property

Add functions to iterate on all property with livetree
- dev_read_first_prop
- dev_read_next_prop
- dev_read_prop_by_prop
and
- ofnode_get_first_property
- ofnode_get_next_property
- ofnode_get_property_by_prop

And helper: dev_for_each_property

For example:
struct ofprop property;

dev_for_each_property(property, config) {
	value = dev_read_prop_by_prop(&property, &propname, &len);

or:

for (res = ofnode_get_first_property(node, &property);
     !res;
     res = ofnode_get_next_property(&property))
{
     value = ofnode_get_property_by_prop(&property, &propname, &len);
....
}

Signed-off-by: Patrick Delaunay <patrick.delaunay@st.com>
Reviewed-by: Simon Glass <sjg@chromium.org>

drivers/core/of_access.c

@@ -171,6 +171,38 @@ const void *of_get_property(const struct device_node *np, const char *name,
 	return pp ? pp->value : NULL;
 }
 
+const struct property *of_get_first_property(const struct device_node *np)
+{
+	if (!np)
+		return NULL;
+
+	return  np->properties;
+}
+
+const struct property *of_get_next_property(const struct device_node *np,
+					    const struct property *property)
+{
+	if (!np)
+		return NULL;
+
+	return property->next;
+}
+
+const void *of_get_property_by_prop(const struct device_node *np,
+				    const struct property *property,
+				    const char **name,
+				    int *lenp)
+{
+	if (!np || !property)
+		return NULL;
+	if (name)
+		*name = property->name;
+	if (lenp)
+		*lenp = property->length;
+
+	return property->value;
+}
+
 static const char *of_prop_next_string(struct property *prop, const char *cur)
 {
 	const void *curv = cur;