dm: core: Allow uclass to set up a device's child before it is probed

Some buses need to set up their devices before they can be used. This setup
may well be common to all buses in a particular uclass. Support a common
pre-probe method for the uclass, called before any bus devices are probed.

Signed-off-by: Simon Glass <sjg@chromium.org>
Reviewed-by: Masahiro Yamada <yamada.m@jp.panasonic.com>
diff --git a/include/dm/uclass-internal.h b/include/dm/uclass-internal.h
index f718f37..f2f254a 100644
--- a/include/dm/uclass-internal.h
+++ b/include/dm/uclass-internal.h
@@ -44,6 +44,17 @@
 int uclass_unbind_device(struct udevice *dev);
 
 /**
+ * uclass_pre_probe_child() - Deal with a child that is about to be probed
+ *
+ * Perform any pre-processing that is needed by the uclass before it can be
+ * probed.
+ *
+ * @dev:	Pointer to the device
+ * #return 0 on success, -ve on error
+ */
+int uclass_pre_probe_child(struct udevice *dev);
+
+/**
  * uclass_post_probe_device() - Deal with a device that has just been probed
  *
  * Perform any post-processing of a probed device that is needed by the