Bluetooth: btusb: Add CONFIG_BT_HCIBTUSB_POLL_SYNC

This adds CONFIG_BT_HCIBTUSB_POLL_SYNC which can be used to set the
default behavior of Bluetooth USB controller with respect to poll
synchronization of its endpoits.
Signed-off-by: Luiz Augusto von Dentz <luiz.von.dentz@intel.com>
Tested-by: Tedd Ho-Jeong An <tedd.an@intel.com>

drivers/bluetooth/Kconfig

@@ -45,6 +45,16 @@ config BT_HCIBTUSB_AUTOSUSPEND
 	  This can be overridden by passing btusb.enable_autosuspend=[y|n]
 	  on the kernel commandline.
 
+config BT_HCIBTUSB_POLL_SYNC
+	bool "Enable USB poll_sync for Bluetooth USB devices by default"
+	depends on BT_HCIBTUSB
+	help
+	  poll_sync synchronizes the USB data and event endpoints by
+	  prioritizing the later.
+
+	  Say Y here to enable USB poll_sync for Bluetooth USB devices by
+	  default.
+
 config BT_HCIBTUSB_BCM
 	bool "Broadcom protocol support"
 	depends on BT_HCIBTUSB

drivers/bluetooth/btusb.c

@@ -32,6 +32,7 @@
 static bool disable_scofix;
 static bool force_scofix;
 static bool enable_autosuspend = IS_ENABLED(CONFIG_BT_HCIBTUSB_AUTOSUSPEND);
+static bool enable_poll_sync = IS_ENABLED(CONFIG_BT_HCIBTUSB_POLL_SYNC);
 static bool reset = true;
 
 static struct usb_driver btusb_driver;
@@ -4075,6 +4076,8 @@ static int btusb_probe(struct usb_interface *intf,
 	if (enable_autosuspend)
 		usb_enable_autosuspend(data->udev);
 
+	data->poll_sync = enable_poll_sync;
+
 	err = hci_register_dev(hdev);
 	if (err < 0)
 		goto out_free_dev;