[PATCH v2 2/2] usb: roles: get usb role switch from parent only for usb-b-connector

[Xu Yang <xu.yang_2@nxp.com>]

usb_role_switch_is_parent() was walking up to the parent node and checking
for the "usb-role-switch" property regardless of the type of the passed
fwnode. This could cause unrelated device nodes to be probed as potential
role switch parent, leading to spurious matches and "-EPROBE_DEFER" being
returned infinitely.

Till now only Type-B connector node will have a parent node which may
present "usb-role-switch" property and register the role switch device.
For Type-C connector node, its parent node will always be a Type-C chip
device which will never register the role switch device. However, it may
still present a non-boolean "usb-role-switch = <&usb_controller>" property
for historical compatibility.

So restrict the helper to only operate on Type-B connector when attempting
to get the role switch from parent node.

Fixes: 6fadd72943b8 ("usb: roles: get usb-role-switch from parent")
Cc: stable@vger.kernel.org
Signed-off-by: Xu Yang <xu.yang_2@nxp.com>

---
Changes in v2:
 - new patch
---
 drivers/usb/roles/class.c | 7 ++++++-
 1 file changed, 6 insertions(+), 1 deletion(-)

diff --git a/drivers/usb/roles/class.c b/drivers/usb/roles/class.c
index b8e28ceca51e..edec139b68b5 100644
--- a/drivers/usb/roles/class.c
+++ b/drivers/usb/roles/class.c
@@ -139,9 +139,14 @@ static void *usb_role_switch_match(const struct fwnode_handle *fwnode, const cha
 static struct usb_role_switch *
 usb_role_switch_is_parent(struct fwnode_handle *fwnode)
 {
-	struct fwnode_handle *parent = fwnode_get_parent(fwnode);
+	struct fwnode_handle *parent;
 	struct device *dev;
 
+	if (!fwnode_device_is_compatible(fwnode, "usb-b-connector"))
+		return NULL;
+
+	parent = fwnode_get_parent(fwnode);
+
 	if (!fwnode_property_present(parent, "usb-role-switch")) {
 		fwnode_handle_put(parent);
 		return NULL;
-- 
2.34.1