> I assume the claims of click-to-unlock (which I assume people include in the "software patent" category) talk about features of an iPhone (a piece of hardware) more than about computation steps.
That's "slide to unlock", and it's not a feature of the iPhone hardware, but rather a feature of iOS (software). The hardware used is completely incidental to the subject of the patent. Actually, it's more of a user-interface patent than a software patent--as you say, it's not really about the computational steps involved--but if anything, UI patents are even harder to justify than patents on algorithms. A trademark would be much more appropriate (and more limited in scope).