diff --git a/drivers/usb/misc/iowarrior.c b/drivers/usb/misc/iowarrior.c
index 4afd1ace3d32..70ec29681526 100644
--- a/drivers/usb/misc/iowarrior.c
+++ b/drivers/usb/misc/iowarrior.c
@@ -2,8 +2,9 @@
 /*
  *  Native support for the I/O-Warrior USB devices
  *
- *  Copyright (c) 2003-2005  Code Mercenaries GmbH
- *  written by Christian Lucht <lucht@codemercs.com>
+ *  Copyright (c) 2003-2005, 2020  Code Mercenaries GmbH
+ *  written by Christian Lucht <lucht@codemercs.com> and
+ *  Christoph Jung <jung@codemercs.com>
  *
  *  based on
 
@@ -802,14 +803,28 @@ static int iowarrior_probe(struct usb_interface *interface,
 
 	/* we have to check the report_size often, so remember it in the endianness suitable for our machine */
 	dev->report_size = usb_endpoint_maxp(dev->int_in_endpoint);
-	if ((dev->interface->cur_altsetting->desc.bInterfaceNumber == 0) &&
-	    ((dev->product_id == USB_DEVICE_ID_CODEMERCS_IOW56) ||
-	     (dev->product_id == USB_DEVICE_ID_CODEMERCS_IOW56AM) ||
-	     (dev->product_id == USB_DEVICE_ID_CODEMERCS_IOW28) ||
-	     (dev->product_id == USB_DEVICE_ID_CODEMERCS_IOW28L) ||
-	     (dev->product_id == USB_DEVICE_ID_CODEMERCS_IOW100)))
-		/* IOWarrior56 has wMaxPacketSize different from report size */
-		dev->report_size = 7;
+
+	/*
+	 * Some devices need the report size to be different than the
+	 * endpoint size.
+	 */
+	if (dev->interface->cur_altsetting->desc.bInterfaceNumber == 0) {
+		switch (dev->product_id) {
+		case USB_DEVICE_ID_CODEMERCS_IOW56:
+		case USB_DEVICE_ID_CODEMERCS_IOW56AM:
+			dev->report_size = 7;
+			break;
+
+		case USB_DEVICE_ID_CODEMERCS_IOW28:
+		case USB_DEVICE_ID_CODEMERCS_IOW28L:
+			dev->report_size = 4;
+			break;
+
+		case USB_DEVICE_ID_CODEMERCS_IOW100:
+			dev->report_size = 13;
+			break;
+		}
+	}
 
 	/* create the urb and buffer for reading */
 	dev->int_in_urb = usb_alloc_urb(0, GFP_KERNEL);