Answer: While I can think of some white flowered fragrant vines, the "hint of violet" is not ringing a bell with the exception of some of the jasmines -- and their blooms are starry, not trumpets. But, here are some possibilities.
I should mention this might be the sweet autumn or fall blooming clematis (Clematis paniculata) since the leaves are clematis-like, although I would describe these flowers as looking starry. You may need to cut and paste the complete url to make it work correctly.
Night jessamine or jasmine (Cestrum nocturnum) has white tublular blooms, extremely fragrant.
Madagascar jasmine (Stephanotis) has trumpet shaped blooms in clusters, but the foliage is more leathery than a clematis.
If your vine is not one of the above, I would suggest you check with a professionally trained nurseryman, your local county extension, or possibly work with a reference librarian to see if you can identify it from a photo. Good luck with your quest!
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