If you've been in photography for more than ten years, you probably remember the way things used to be on old film cameras. There was no electronic interconnect between the lens and the body, so lens-related functions (focus, zoom, aperture) were on the lens and body-related functions (ASA, shutter speed) were on the body. That changed as autofocus and auto-exposure, particularly on digital cameras, necessitated a data connection between the lens and the body. While we never did away with the focus and zoom rings, aperture went right out the window and was electronically controlled.
A few nice cameras have aperture rings now — the X100, for instance — but generally speaking you can't find one except on professional cinema gear these days. But Canon may be looking to change that.
A recent patent detailed at Photography Bay shows a system for controlling the functions of a lens using three on-lens rings (or two on a prime, presumably), the hindmost of which controls a diaphragm, which we can take to mean the iris. Old-school photographers will be overjoyed.
Newer camera systems have attempted to modernize the ring system by having one ring stand in for all three, its active function chosen by a switch or setting. A reasonable attempt but (I suspect) unsatisfying for many photographers.
One point that isn't clear is whether the ring will be stepped or stepless. Traditionally, aperture rings have moved in mechanically-separated 1/3-stop steps, which aids in keeping exposures consistent and prevents an aperture equivalent to zoom creep. But the stepped exposure dial is a pain for motion video, where the steps are easily perceived as they change. There's no reason why the iris shouldn't be able to move smoothly from open to shut and stop anywhere along the way (perhaps rounded off to the nearest third), and it may be that this is a feature planned for Canon's next big announcement in November.
No announcements have been made, of course, but the patent was interesting to warrant a post anyway.