[PATCH] topology: Fix inaccurate comments when building a widget element

[mengdong.lin@linux.intel.com]

From: Mengdong Lin <mengdong.lin@linux.intel.com>

The original comments use 'control' by mistake when building a widget.
Also describe the difference between the referenced controls defined by
C API and text conf file.

Signed-off-by: Mengdong Lin <mengdong.lin@linux.intel.com>

diff --git a/src/topology/dapm.c b/src/topology/dapm.c
index e3c90d8..0141653 100644
--- a/src/topology/dapm.c
+++ b/src/topology/dapm.c
@@ -150,7 +150,7 @@ static int copy_dapm_control(struct tplg_elem *elem, struct tplg_elem *ref)
 	return 0;
 }
 
-/* check referenced controls for a widget */
+/* Merge referenced controls and private data for a widget */
 static int tplg_build_widget(snd_tplg_t *tplg,
 	struct tplg_elem *elem)
 {
@@ -160,7 +160,12 @@ static int tplg_build_widget(snd_tplg_t *tplg,
 
 	base = &elem->ref_list;
 
-	/* for each ref in this control elem */
+	/* Look up and merge each control or data reference of this
+	 * widget element. For a widget defined by C API, its control
+	 * references are already bound and can be directly merged
+	 * without lookup. Only control references defined by text
+	 * conf file need lookup before being merged.
+	 */
 	list_for_each(pos, base) {
 
 		ref = list_entry(pos, struct tplg_ref, list);
-- 
2.5.0