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/test/dm/test-fdt.c b/test/dm/test-fdt.c
index dfcb3af..b8ee959 100644
--- a/test/dm/test-fdt.c
+++ b/test/dm/test-fdt.c
@@ -51,6 +51,13 @@
 
 	priv->ping_total += DM_TEST_START_TOTAL;
 
+	/*
+	 * If this device is on a bus, the uclass_flag will be set before
+	 * calling this function. This is used by
+	 * dm_test_bus_child_pre_probe_uclass().
+	 */
+	priv->uclass_total += priv->uclass_flag;
+
 	return 0;
 }