[v3,02/21] dm: core: add ofnode and dev function to iterate on node property

diff --git a/drivers/core/of_access.c b/drivers/core/of_access.c
index 945b81448c..86fe42ad14 100644
--- a/drivers/core/of_access.c
+++ b/drivers/core/of_access.c
@@ -170,6 +170,38 @@  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;
diff --git a/drivers/core/ofnode.c b/drivers/core/ofnode.c
index 8f0eab2ca6..cb27562fec 100644
--- a/drivers/core/ofnode.c
+++ b/drivers/core/ofnode.c
@@ -536,6 +536,54 @@  const void *ofnode_get_property(ofnode node, const char *propname, int *lenp)
 				   propname, lenp);
 }
 
+int ofnode_get_first_property(ofnode node, struct ofprop *prop)
+{
+	prop->node = node;
+
+	if (ofnode_is_np(node)) {
+		prop->prop = of_get_first_property(ofnode_to_np(prop->node));
+		if (!prop->prop)
+			return -FDT_ERR_NOTFOUND;
+	} else {
+		prop->offset =
+			fdt_first_property_offset(gd->fdt_blob,
+						  ofnode_to_offset(prop->node));
+		if (prop->offset < 0)
+			return prop->offset;
+	}
+
+	return 0;
+}
+
+int ofnode_get_next_property(struct ofprop *prop)
+{
+	if (ofnode_is_np(prop->node)) {
+		prop->prop = of_get_next_property(ofnode_to_np(prop->node),
+						  prop->prop);
+		if (!prop->prop)
+			return -FDT_ERR_NOTFOUND;
+	} else {
+		prop->offset = fdt_next_property_offset(gd->fdt_blob,
+							prop->offset);
+		if (prop->offset  < 0)
+			return prop->offset;
+	}
+
+	return 0;
+}
+
+const void *ofnode_get_property_by_prop(const struct ofprop *prop,
+					const char **propname, int *lenp)
+{
+	if (ofnode_is_np(prop->node))
+		return of_get_property_by_prop(ofnode_to_np(prop->node),
+					       prop->prop, propname, lenp);
+	else
+		return fdt_getprop_by_offset(gd->fdt_blob,
+					     prop->offset,
+					     propname, lenp);
+}
+
 bool ofnode_is_available(ofnode node)
 {
 	if (ofnode_is_np(node))
diff --git a/drivers/core/read.c b/drivers/core/read.c
index 9602e52d1b..a9f5d147b2 100644
--- a/drivers/core/read.c
+++ b/drivers/core/read.c
@@ -238,6 +238,22 @@  const void *dev_read_prop(struct udevice *dev, const char *propname, int *lenp)
 	return ofnode_get_property(dev_ofnode(dev), propname, lenp);
 }
 
+int dev_read_first_prop(struct udevice *dev, struct ofprop *prop)
+{
+	return ofnode_get_first_property(dev_ofnode(dev), prop);
+}
+
+int dev_read_next_prop(struct ofprop *prop)
+{
+	return ofnode_get_next_property(prop);
+}
+
+const void *dev_read_prop_by_prop(struct ofprop *prop,
+				  const char **propname, int *lenp)
+{
+	return ofnode_get_property_by_prop(prop, propname, lenp);
+}
+
 int dev_read_alias_seq(struct udevice *dev, int *devnump)
 {
 	ofnode node = dev_ofnode(dev);
diff --git a/include/dm/of_access.h b/include/dm/of_access.h
index 13fedb7cf5..1eb1ce13d0 100644
--- a/include/dm/of_access.h
+++ b/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
diff --git a/include/dm/ofnode.h b/include/dm/ofnode.h
index 5c4cbf0998..9ee5556490 100644
--- a/include/dm/ofnode.h
+++ b/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
  *
@@ -543,7 +568,7 @@  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
@@ -552,6 +577,42 @@  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
  *
diff --git a/include/dm/read.h b/include/dm/read.h
index d37fcb504d..3c6bed7bff 100644
--- a/include/dm/read.h
+++ b/include/dm/read.h
@@ -465,6 +465,42 @@  int dev_read_phandle(struct udevice *dev);
  */
 const void *dev_read_prop(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(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
  *
@@ -812,6 +848,23 @@  static inline const void *dev_read_prop(struct udevice *dev,
 	return ofnode_get_property(dev_ofnode(dev), propname, lenp);
 }
 
+static inline int dev_read_first_prop(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(struct udevice *dev, int *devnump)
 {
 	return fdtdec_get_alias_seq(gd->fdt_blob, dev->uclass->uc_drv->name,
@@ -889,4 +942,18 @@  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
diff --git a/test/dm/Makefile b/test/dm/Makefile
index 0c2fd5cb5e..6a1af1511a 100644
--- a/test/dm/Makefile
+++ b/test/dm/Makefile
@@ -29,6 +29,7 @@  obj-$(CONFIG_LED) += led.o
 obj-$(CONFIG_DM_MAILBOX) += mailbox.o
 obj-$(CONFIG_DM_MMC) += mmc.o
 obj-y += ofnode.o
+obj-y += ofread.o
 obj-$(CONFIG_OSD) += osd.o
 obj-$(CONFIG_DM_VIDEO) += panel.o
 obj-$(CONFIG_DM_PCI) += pci.o
diff --git a/test/dm/ofread.c b/test/dm/ofread.c
new file mode 100644
index 0000000000..f2a1382259
--- /dev/null
+++ b/test/dm/ofread.c
@@ -0,0 +1,50 @@ 
+// SPDX-License-Identifier: GPL-2.0+
+
+#include <common.h>
+#include <dm.h>
+#include <dm/test.h>
+#include <test/ut.h>
+
+static int dm_test_ofnode_get_property_by_prop(struct unit_test_state *uts)
+{
+	ofnode node;
+	struct ofprop prop;
+	const void *value;
+	const char *propname;
+	int res, len, count = 0;
+
+	node = ofnode_path("/cros-ec/flash");
+	for (res = ofnode_get_first_property(node, &prop);
+	     !res;
+	     res = ofnode_get_next_property(&prop)) {
+		value = ofnode_get_property_by_prop(&prop, &propname, &len);
+		ut_assertnonnull(value);
+		switch (count) {
+		case 0:
+			ut_asserteq_str("image-pos", propname);
+			ut_asserteq(4, len);
+			break;
+		case 1:
+			ut_asserteq_str("size", propname);
+			ut_asserteq(4, len);
+			break;
+		case 2:
+			ut_asserteq_str("erase-value", propname);
+			ut_asserteq(4, len);
+			break;
+		case 3:
+			/* only for platdata */
+			ut_asserteq_str("name", propname);
+			ut_asserteq(6, len);
+			ut_asserteq_str("flash", value);
+			break;
+		default:
+			break;
+		}
+		count++;
+	}
+
+	return 0;
+}
+DM_TEST(dm_test_ofnode_get_property_by_prop,
+	DM_TESTF_SCAN_PDATA | DM_TESTF_SCAN_FDT);