cl-libusb provides an easy interface to libusb-0.1. There are two
systems/packages: libusb-ffi, which provides a (somewhat lispified)
ffi to libusb-0.1, and cl-libusb, which provides an easier interface.

Buffers are dealt with using unsigned byte static vectors. Converting
existing software to use static vectors instead of foreign arrays
should be straight-forward:
1. In your project, make sure to use static-vectors instead of antik
   and grid,
2. If you call USB-BULK-WRITE or USB-INTERRUPT-WRITE, make sure the
   buffer is a static vector instead of a foreign array:
   Instead of (GRID:MAKE-FOREIGN-ARRAY '(UNSIGNED-BYTE 8) :DIMENSIONS LENGTH)
   to make the array, use (STATIC-VECTORS:MAKE-STATIC-VECTOR LENGTH) and
   fill the array as if it is a normal common lisp array. After the
   call to -WRITE functions, make sure to use STATIC-VECTORS:FREE-STATIC-VECTOR
   to ensure the memory will be freed.
3. If you call USB-BULK-READ or USB-INTERRUPT-READ, be aware that the
   buffer is a static vector instead of a foreign array:
   The returned array can be simply be used as if it is a normal common
   lisp array for reading / parsing the output of the -READ functions.
   Make sure to use STATIC-VECTORS:FREE-STATIC-VECTOR to ensure that the
   associated memory will be freed.

libusb-ffi (and thus cl-libusb) is not complete, but should be usable.

Tested and found to work on:
linux amd64 (sbcl)
linux raspberry pi (sbcl-1.3.1-debian)