[PATCH v6 08/10] usb: roles: get usb-role-switch from parent

[Chunfeng Yun]

when the USB host controller is the parent of the connector,
usually type-B, sometimes don't need the graph, so we should
check whether it's parent registers usb-role-switch or not
firstly, and get it if exists.

Signed-off-by: Heikki Krogerus <heikki.krogerus@xxxxxxxxxxxxxxx>
Signed-off-by: Chunfeng Yun <chunfeng.yun@xxxxxxxxxxxx>
---
v6:
  new patch
---
 drivers/usb/roles/class.c | 25 +++++++++++++++++++++----
 1 file changed, 21 insertions(+), 4 deletions(-)

diff --git a/drivers/usb/roles/class.c b/drivers/usb/roles/class.c
index aab795b54c7f..1f6af0ef3954 100644
--- a/drivers/usb/roles/class.c
+++ b/drivers/usb/roles/class.c
@@ -114,6 +114,19 @@ static void *usb_role_switch_match(struct device_connection *con, int ep,
 	return dev ? to_role_switch(dev) : ERR_PTR(-EPROBE_DEFER);
 }
 
+static struct usb_role_switch *
+usb_role_switch_is_parent(struct fwnode_handle *fwnode)
+{
+	struct fwnode_handle *parent = fwnode_get_parent(fwnode);
+	struct device *dev;
+
+	if (!parent || !fwnode_property_present(parent, "usb-role-switch"))
+		return NULL;
+
+	dev = class_find_device(role_class, NULL, parent, switch_fwnode_match);
+	return dev ? to_role_switch(dev) : ERR_PTR(-EPROBE_DEFER);
+}
+
 /**
  * usb_role_switch_get - Find USB role switch linked with the caller
  * @dev: The caller device
@@ -125,8 +138,10 @@ struct usb_role_switch *usb_role_switch_get(struct device *dev)
 {
 	struct usb_role_switch *sw;
 
-	sw = device_connection_find_match(dev, "usb-role-switch", NULL,
-					  usb_role_switch_match);
+	sw = usb_role_switch_is_parent(dev_fwnode(dev));
+	if (!sw)
+		sw = device_connection_find_match(dev, "usb-role-switch", NULL,
+						  usb_role_switch_match);
 
 	if (!IS_ERR_OR_NULL(sw))
 		WARN_ON(!try_module_get(sw->dev.parent->driver->owner));
@@ -146,8 +161,10 @@ struct usb_role_switch *fwnode_usb_role_switch_get(struct fwnode_handle *fwnode)
 {
 	struct usb_role_switch *sw;
 
-	sw = fwnode_connection_find_match(fwnode, "usb-role-switch", NULL,
-					  usb_role_switch_match);
+	sw = usb_role_switch_is_parent(fwnode);
+	if (!sw)
+		sw = fwnode_connection_find_match(fwnode, "usb-role-switch",
+						  NULL, usb_role_switch_match);
 	if (!IS_ERR_OR_NULL(sw))
 		WARN_ON(!try_module_get(sw->dev.parent->driver->owner));
 
-- 
2.21.0