dm: core: Allow parents to pass data to children during probe

Buses sometimes want to pass data to their children when they are probed.
For example, a SPI bus may want to tell the slave device about the chip
select it is connected to.

Add a new function to permit the parent data to be supplied to the child.

Signed-off-by: Simon Glass <sjg@chromium.org>
Acked-by: Jagannadha Sutradharudu Teki <jagannadh.teki@gmail.com>
diff --git a/include/dm/device-internal.h b/include/dm/device-internal.h
index 7005d03..44cb7ef 100644
--- a/include/dm/device-internal.h
+++ b/include/dm/device-internal.h
@@ -66,6 +66,19 @@
 int device_probe(struct udevice *dev);
 
 /**
+ * device_probe() - Probe a child device, activating it
+ *
+ * Activate a device so that it is ready for use. All its parents are probed
+ * first. The child is provided with parent data if parent_priv is not NULL.
+ *
+ * @dev: Pointer to device to probe
+ * @parent_priv: Pointer to parent data. If non-NULL then this is provided to
+ * the child.
+ * @return 0 if OK, -ve on error
+ */
+int device_probe_child(struct udevice *dev, void *parent_priv);
+
+/**
  * device_remove() - Remove a device, de-activating it
  *
  * De-activate a device so that it is no longer ready for use. All its