[PATCH v3 1/2] usb: dwc3: drd: Avoid error when extcon is missing

[Sam Protsenko <semen.protsenko@linaro.org>]

If "port" node is missing in PHY controller node, dwc3_get_extcon()
isn't able to find extcon device. This is perfectly fine in case when
"usb-role-switch" or OTG is used, but next misleading error message is
printed in that case, from of_graph_get_remote_node():

    OF: graph: no port node found in /phy@1234abcd

Avoid printing that message by checking if port node exists in PHY node
before calling of_graph_get_remote_node().

Signed-off-by: Sam Protsenko <semen.protsenko@linaro.org>
Cc: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
---
Changes in v3:
  - Split patch into two patches: logic diff and style diff

 drivers/usb/dwc3/drd.c | 5 ++++-
 1 file changed, 4 insertions(+), 1 deletion(-)

diff --git a/drivers/usb/dwc3/drd.c b/drivers/usb/dwc3/drd.c
index 3e1c1aacf002..312a4d060e80 100644
--- a/drivers/usb/dwc3/drd.c
+++ b/drivers/usb/dwc3/drd.c
@@ -463,7 +463,10 @@ static struct extcon_dev *dwc3_get_extcon(struct dwc3 *dwc)
 	}
 
 	np_phy = of_parse_phandle(dev->of_node, "phys", 0);
-	np_conn = of_graph_get_remote_node(np_phy, -1, -1);
+	if (of_graph_is_present(np_phy))
+		np_conn = of_graph_get_remote_node(np_phy, -1, -1);
+	else
+		np_conn = NULL;
 
 	if (np_conn)
 		edev = extcon_find_edev_by_node(np_conn);
-- 
2.29.2