dm: core: Add function to get child count of ofnode or device

This patch add function used to get the child count of
a ofnode or a device

Signed-off-by: Frank Wunderlich <frank-w@public-files.de>
Reviewed-by: Simon Glass <sjg@chromium.org>
diff --git a/drivers/core/ofnode.c b/drivers/core/ofnode.c
index 20871a6..e3c42da 100644
--- a/drivers/core/ofnode.c
+++ b/drivers/core/ofnode.c
@@ -474,6 +474,17 @@
 	return ofnode_path(prop);
 }
 
+int ofnode_get_child_count(ofnode parent)
+{
+	ofnode child;
+	int num = 0;
+
+	ofnode_for_each_subnode(child, parent)
+		num++;
+
+	return num;
+}
+
 static int decode_timing_property(ofnode node, const char *name,
 				  struct timing_entry *result)
 {
diff --git a/drivers/core/read.c b/drivers/core/read.c
index 47b8e03..3d421f7 100644
--- a/drivers/core/read.c
+++ b/drivers/core/read.c
@@ -352,3 +352,8 @@
 
 	return addr;
 }
+
+int dev_get_child_count(const struct udevice *dev)
+{
+	return ofnode_get_child_count(dev_ofnode(dev));
+}
diff --git a/include/dm/ofnode.h b/include/dm/ofnode.h
index 618fc10..a0d3df7 100644
--- a/include/dm/ofnode.h
+++ b/include/dm/ofnode.h
@@ -880,6 +880,14 @@
 	     node = ofnode_next_subnode(node))
 
 /**
+ * ofnode_get_child_count() - get the child count of a ofnode
+ *
+ * @node: valid node to get its child count
+ * @return the number of subnodes
+ */
+int ofnode_get_child_count(ofnode parent);
+
+/**
  * ofnode_translate_address() - Translate a device-tree address
  *
  * Translate an address from the device-tree into a CPU physical address. This
diff --git a/include/dm/read.h b/include/dm/read.h
index 03c15b8..b952551 100644
--- a/include/dm/read.h
+++ b/include/dm/read.h
@@ -669,6 +669,14 @@
  */
 int dev_read_alias_highest_id(const char *stem);
 
+/**
+ * dev_get_child_count() - get the child count of a device
+ *
+ * @dev: device to use for interation (struct udevice *)
+ * @return the count of child subnode
+ */
+int dev_get_child_count(const struct udevice *dev);
+
 #else /* CONFIG_DM_DEV_READ_INLINE is enabled */
 
 static inline int dev_read_u32(const struct udevice *dev,
@@ -978,6 +986,11 @@
 	return fdtdec_get_alias_highest_id(gd->fdt_blob, stem);
 }
 
+static inline int dev_get_child_count(const struct udevice *dev)
+{
+	return ofnode_get_child_count(dev_ofnode(dev));
+}
+
 #endif /* CONFIG_DM_DEV_READ_INLINE */
 
 /**