mfd: twl4030-audio: Fix sibling-node lookup

BugLink: http://bugs.launchpad.net/bugs/1745069

commit 0a423772 upstream.

A helper purported to look up a child node based on its name was using
the wrong of-helper and ended up prematurely freeing the parent of-node
while leaking any matching node.

To make things worse, any matching node would not even necessarily be a
child node as the whole device tree was searched depth-first starting at
the parent.

Fixes: 019a7e6b ("mfd: twl4030-audio: Add DT support")
Signed-off-by: Johan Hovold <johan@kernel.org>
Acked-by: Peter Ujfalusi <peter.ujfalusi@ti.com>
Signed-off-by: Lee Jones <lee.jones@linaro.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Signed-off-by: Khalid Elmously <khalid.elmously@canonical.com>
Signed-off-by: Stefan Bader <stefan.bader@canonical.com>

drivers/mfd/twl4030-audio.c

@@ -159,13 +159,18 @@ unsigned int twl4030_audio_get_mclk(void)
 EXPORT_SYMBOL_GPL(twl4030_audio_get_mclk);
 
 static bool twl4030_audio_has_codec(struct twl4030_audio_data *pdata,
-			      struct device_node *node)
+			      struct device_node *parent)
 {
+	struct device_node *node;
+
 	if (pdata && pdata->codec)
 		return true;
 
-	if (of_find_node_by_name(node, "codec"))
+	node = of_get_child_by_name(parent, "codec");
+	if (node) {
+		of_node_put(node);
 		return true;
+	}
 
 	return false;
 }