uclass: Add dev_get_uclass_index() to get the uclass/index of a device

This function is the reciprocal of uclass_find_device().
It will be used to print the index information in dm tree dump.

Signed-off-by: Jean-Jacques Hiblot <jjhiblot@ti.com>

drivers/core/uclass.c

@@ -171,6 +171,27 @@ enum uclass_id uclass_get_by_name(const char *name)
 	return UCLASS_INVALID;
 }
 
+int dev_get_uclass_index(struct udevice *dev, struct uclass **ucp)
+{
+	struct udevice *iter;
+	struct uclass *uc = dev->uclass;
+	int i = 0;
+
+	if (list_empty(&uc->dev_head))
+		return -ENODEV;
+
+	list_for_each_entry(iter, &uc->dev_head, uclass_node) {
+		if (iter == dev) {
+			if (ucp)
+				*ucp = uc;
+			return i;
+		}
+		i++;
+	}
+
+	return -ENODEV;
+}
+
 int uclass_find_device(enum uclass_id id, int index, struct udevice **devp)
 {
 	struct uclass *uc;

include/dm/uclass-internal.h

@@ -23,6 +23,17 @@
  */
 int uclass_get_device_tail(struct udevice *dev, int ret, struct udevice **devp);
 
+/**
+ * dev_get_uclass_index() - Get uclass and index of device
+ * @dev:	- in - Device that we want the uclass/index of
+ * @ucp:	- out - A pointer to the uclass the device belongs to
+ *
+ * The device is not prepared for use - this is an internal function.
+ *
+ * @return the index of the device in the uclass list or -ENODEV if not found.
+ */
+int dev_get_uclass_index(struct udevice *dev, struct uclass **ucp);
+
 /**
  * uclass_find_device() - Return n-th child of uclass
  * @id:		Id number of the uclass