Messages in this thread | | | From | David Brownell <> | Subject | Re: [PATCH/RFC] hardware irq debouncing support | Date | Tue, 7 Oct 2008 10:19:08 -0700 |
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On Monday 06 October 2008, Pavel Machek wrote: > How is this going to work with shared interrupt lines? If one handler > wants debouncing and second handler does not, you'll loose interrupts > for second handler?
That'd be as hardware dependent as the bad decision to mix such signals on one line in the first place! As a rule, nothing gets lost -- systems care about such events stable at the millisecond granuarity, not nanosecond -- but I can't speak for all possible bad hardware designs.
Recall that the systems with this support generally have no shortage of interrupt lines, and thus no reason to share them. The boards I'm working with right now have over two hundred GPIOs, and all but a handful of them (if you exaggerate "two" to be a "handful"!) can be configured as interrupt inputs.
And there's strong incentive NOT to share them ... if a signal is dedicated to e.g. MMC1 card detect, it can gate the regulator dedicated to that slot; but not if that signal is shared with some other status. If two simple buttons both trigger the same interrupt, you can't tell them apart. And so on.
- Dave
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