usb: roles: get usb-role-switch from parent

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.

Suggested-by: Heikki Krogerus <heikki.krogerus@linux.intel.com>
Signed-off-by: Chunfeng Yun <chunfeng.yun@mediatek.com>
Link: https://lore.kernel.org/r/1567070558-29417-9-git-send-email-chunfeng.yun@mediatek.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

1 files changed, 21 insertions, 4 deletions

diff --git a/drivers/usb/roles/class.c b/drivers/usb/roles/class.c
index 2abb6fe384ca..94b4e7db2b94 100644
--- a/drivers/usb/roles/class.c
+++ b/drivers/usb/roles/class.c
@@ -102,6 +102,19 @@ 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_by_fwnode(role_class, parent);
+        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
@@ -113,8 +126,10 @@ 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));
@@ -134,8 +149,10 @@ 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));