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>

include/dm/of_access.h

@@ -103,6 +103,46 @@ struct property *of_find_property(const struct device_node *np,
 const void *of_get_property(const struct device_node *np, const char *name,
 			    int *lenp);
 
+/**
+ * of_get_first_property()- get to the pointer of the first property
+ *
+ * Get pointer to the first property of the node, it is used to iterate
+ * and read all the property with of_get_next_property_by_prop().
+ *
+ * @np: Pointer to device node
+ * @return pointer to property or NULL if not found
+ */
+const struct property *of_get_first_property(const struct device_node *np);
+
+/**
+ * of_get_next_property() - get to the pointer of the next property
+ *
+ * Get pointer to the next property of the node, it is used to iterate
+ * and read all the property with of_get_property_by_prop().
+ *
+ * @np: Pointer to device node
+ * @property: pointer of the current property
+ * @return pointer to next property or NULL if not found
+ */
+const struct property *of_get_next_property(const struct device_node *np,
+					    const struct property *property);
+
+/**
+ * of_get_property_by_prop() - get a property value of a node property
+ *
+ * Get value for the property identified by node and property pointer.
+ *
+ * @node: node to read
+ * @property: pointer of the property to read
+ * @propname: place to property name on success
+ * @lenp: place to put length on success
+ * @return pointer to property value or NULL if error
+ */
+const void *of_get_property_by_prop(const struct device_node *np,
+				    const struct property *property,
+				    const char **name,
+				    int *lenp);
+
 /**
  * of_device_is_compatible() - Check if the node matches given constraints
  * @device: pointer to node

include/dm/ofnode.h

@@ -58,6 +58,31 @@ struct ofnode_phandle_args {
 	uint32_t args[OF_MAX_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
  *
@@ -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
@@ -604,6 +629,42 @@ 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
  *

include/dm/read.h

@@ -494,6 +494,42 @@ int dev_read_phandle(const struct udevice *dev);
 const void *dev_read_prop(const struct udevice *dev, const char *propname,
 			  int *lenp);
 
+/**
+ * dev_read_first_prop()- 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 dev_read_prop_by_prop().
+ *
+ * @dev: device to check
+ * @prop: place to put argument reference
+ * @return 0 if OK, -ve on error. -FDT_ERR_NOTFOUND if not found
+ */
+int dev_read_first_prop(const struct udevice *dev, 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 dev_read_prop_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 dev_read_next_prop(struct ofprop *prop);
+
+/**
+ * dev_read_prop_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 *dev_read_prop_by_prop(struct ofprop *prop,
+				  const char **propname, int *lenp);
+
 /**
  * dev_read_alias_seq() - Get the alias sequence number of a node
  *
@@ -860,6 +896,23 @@ static inline const void *dev_read_prop(const struct udevice *dev,
 	return ofnode_get_property(dev_ofnode(dev), propname, lenp);
 }
 
+static inline int dev_read_first_prop(const struct udevice *dev, struct ofprop *prop)
+{
+	return ofnode_get_first_property(dev_ofnode(dev), prop);
+}
+
+static inline int dev_read_next_prop(struct ofprop *prop)
+{
+	return ofnode_get_next_property(prop);
+}
+
+static inline const void *dev_read_prop_by_prop(struct ofprop *prop,
+						const char **propname,
+						int *lenp)
+{
+	return ofnode_get_property_by_prop(prop, propname, lenp);
+}
+
 static inline int dev_read_alias_seq(const struct udevice *dev, int *devnump)
 {
 	return fdtdec_get_alias_seq(gd->fdt_blob, dev->uclass->uc_drv->name,
@@ -941,4 +994,18 @@ static inline int dev_read_alias_highest_id(const char *stem)
 	     ofnode_valid(subnode); \
 	     subnode = ofnode_next_subnode(subnode))
 
+/**
+ * dev_for_each_property() - Helper function to iterate through property
+ *
+ * This creates a for() loop which works through the property in a device's
+ * device-tree node.
+ *
+ * @prop: struct ofprop holding the current property
+ * @dev: device to use for interation (struct udevice *)
+ */
+#define dev_for_each_property(prop, dev) \
+	for (int ret_prop = dev_read_first_prop(dev, &prop); \
+	     !ret_prop; \
+	     ret_prop = dev_read_next_prop(&prop))
+
 #endif