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>

1 files changed, 62 insertions, 1 deletions

diff --git a/include/dm/ofnode.h b/include/dm/ofnode.h
index ce5e366c062..618fc10390e 100644
--- a/include/dm/ofnode.h
+++ b/include/dm/ofnode.h
@@ -59,6 +59,31 @@ struct ofnode_phandle_args {
 };
 
 /**
+ * ofprop - reference to a property of a device tree node
+ *
+ * This struct hold the reference on one property of one node,
+ * using struct ofnode and an offset within the flat device tree or either
+ * a pointer to a struct property in the live device tree.
+ *
+ * Thus we can reference arguments in both the live tree and the flat tree.
+ *
+ * The property reference can also hold a null reference. This corresponds to
+ * a struct property NULL pointer or an offset of -1.
+ *
+ * @node: Pointer to device node
+ * @offset: Pointer into flat device tree, used for flat tree.
+ * @prop: Pointer to property, used for live treee.
+ */
+
+struct ofprop {
+	ofnode node;
+	union {
+		int offset;
+		const struct property *prop;
+	};
+};
+
+/**
  * _ofnode_to_np() - convert an ofnode to a live DT node pointer
  *
  * This cannot be called if the reference contains an offset.
@@ -595,7 +620,7 @@ int ofnode_decode_display_timing(ofnode node, int index,
 				 struct display_timing *config);
 
 /**
- * ofnode_get_property()- - get a pointer to the value of a node property
+ * ofnode_get_property() - get a pointer to the value of a node property
  *
  * @node: node to read
  * @propname: property to read
@@ -605,6 +630,42 @@ int ofnode_decode_display_timing(ofnode node, int index,
 const void *ofnode_get_property(ofnode node, const char *propname, int *lenp);
 
 /**
+ * ofnode_get_first_property()- get the reference of the first property
+ *
+ * Get reference to the first property of the node, it is used to iterate
+ * and read all the property with ofnode_get_property_by_prop().
+ *
+ * @node: node to read
+ * @prop: place to put argument reference
+ * @return 0 if OK, -ve on error. -FDT_ERR_NOTFOUND if not found
+ */
+int ofnode_get_first_property(ofnode node, struct ofprop *prop);
+
+/**
+ * ofnode_get_next_property() - get the reference of the next property
+ *
+ * Get reference to the next property of the node, it is used to iterate
+ * and read all the property with ofnode_get_property_by_prop().
+ *
+ * @prop: reference of current argument and place to put reference of next one
+ * @return 0 if OK, -ve on error. -FDT_ERR_NOTFOUND if not found
+ */
+int ofnode_get_next_property(struct ofprop *prop);
+
+/**
+ * ofnode_get_property_by_prop() - get a pointer to the value of a property
+ *
+ * Get value for the property identified by the provided reference.
+ *
+ * @prop: reference on property
+ * @propname: If non-NULL, place to property name on success,
+ * @lenp: If non-NULL, place to put length on success
+ * @return 0 if OK, -ve on error. -FDT_ERR_NOTFOUND if not found
+ */
+const void *ofnode_get_property_by_prop(const struct ofprop *prop,
+					const char **propname, int *lenp);
+
+/**
  * ofnode_is_available() - check if a node is marked available
  *
  * @node: node to check