diff --git a/src/portable/st/synopsys/dcd_synopsys.c b/src/portable/st/synopsys/dcd_synopsys.c
index b3d82c3a..5a89bb38 100644
--- a/src/portable/st/synopsys/dcd_synopsys.c
+++ b/src/portable/st/synopsys/dcd_synopsys.c
@@ -264,7 +264,7 @@ static void bus_reset(uint8_t rhport)
 }
 
 // Required after new configuration received in case EP0 max packet size has changed
-static void set_EP0_max_pkt_size()
+static void set_EP0_max_pkt_size(void)
 {
   USB_OTG_DeviceTypeDef * dev = DEVICE_BASE(rhport);
   USB_OTG_INEndpointTypeDef * in_ep = IN_EP_BASE(rhport);