usb: dwc3: Do not get extcon device when usb-role-switch is used

The change breaks device tree based platforms with PHY device and use
usb-role-switch instead of an extcon switch. extcon_find_edev_by_node()
will return EPROBE_DEFER if it can not find a device so probing without
an extcon device will be deferred indefinitely. Fix this by
explicitly checking for usb-role-switch.
At least the out-of-tree USB3 support on Apple silicon based platforms
using dwc3 with tipd USB Type-C and PD controller is affected by this
issue.

Fixes: d182c2e ("usb: dwc3: Don't switch OTG -> peripheral if extcon is present")
Cc: [email protected]
Signed-off-by: Janne Grunau <[email protected]>
Acked-by: Thinh Nguyen <[email protected]>
Reviewed-by: Sven Peter <[email protected]>
Link: https://lore.kernel.org/r/[email protected]
Signed-off-by: Greg Kroah-Hartman <[email protected]>

Author: jannau

drivers/usb/dwc3/core.c

@@ -1710,6 +1710,16 @@ static struct extcon_dev *dwc3_get_extcon(struct dwc3 *dwc)
 	if (device_property_read_string(dev, "linux,extcon-name", &name) == 0)
 		return extcon_get_extcon_dev(name);
 
+	/*
+	 * Check explicitly if "usb-role-switch" is used since
+	 * extcon_find_edev_by_node() can not be used to check the absence of
+	 * an extcon device. In the absence of an device it will always return
+	 * EPROBE_DEFER.
+	 */
+	if (IS_ENABLED(CONFIG_USB_ROLE_SWITCH) &&
+	    device_property_read_bool(dev, "usb-role-switch"))
+		return NULL;
+
 	/*
 	 * Try to get an extcon device from the USB PHY controller's "port"
 	 * node. Check if it has the "port" node first, to avoid printing the