static int dt9812_read_info(struct comedi_device *dev,
                            int offset, void *buf, size_t buf_size)
 {
-       struct usb_interface *intf = comedi_to_usb_interface(dev);
-       struct usb_device *usb = interface_to_usbdev(intf);
+       struct usb_device *usb = comedi_to_usb_dev(dev);
        struct dt9812_private *devpriv = dev->private;
        struct dt9812_usb_cmd cmd;
        int count, ret;
                                          int reg_count, u8 *address,
                                          u8 *value)
 {
-       struct usb_interface *intf = comedi_to_usb_interface(dev);
-       struct usb_device *usb = interface_to_usbdev(intf);
+       struct usb_device *usb = comedi_to_usb_dev(dev);
        struct dt9812_private *devpriv = dev->private;
        struct dt9812_usb_cmd cmd;
        int i, count, ret;
                                           int reg_count, u8 *address,
                                           u8 *value)
 {
-       struct usb_interface *intf = comedi_to_usb_interface(dev);
-       struct usb_device *usb = interface_to_usbdev(intf);
+       struct usb_device *usb = comedi_to_usb_dev(dev);
        struct dt9812_private *devpriv = dev->private;
        struct dt9812_usb_cmd cmd;
        int i, count;
                                         int reg_count,
                                         struct dt9812_rmw_byte *rmw)
 {
-       struct usb_interface *intf = comedi_to_usb_interface(dev);
-       struct usb_device *usb = interface_to_usbdev(intf);
+       struct usb_device *usb = comedi_to_usb_dev(dev);
        struct dt9812_private *devpriv = dev->private;
        struct dt9812_usb_cmd cmd;
        int i, count;
 
 static int dt9812_reset_device(struct comedi_device *dev)
 {
-       struct usb_interface *intf = comedi_to_usb_interface(dev);
-       struct usb_device *usb = interface_to_usbdev(intf);
+       struct usb_device *usb = comedi_to_usb_dev(dev);
        struct dt9812_private *devpriv = dev->private;
        u32 serial;
        u16 vendor;