Am 24.03.2009 um 23:16 schrieb Sergey Manucharian: > On Tue, 24 Mar 2009 13:32:22 -0700 > Matthew Kaufman <[email protected]> wrote: > >> I have a 5501 and have installed Linux on it. I've managed to get the >> cs5535_gpio module going, but I'm concerned about the speed of GPIO >> access that way, as to read the value I need to re-open and re-read a >> character device, and I need to poll a GPIO pin about once every 20 >> msec without using too much CPU. >> >> Are there any better drivers and/or user-space code examples that >> would be more appropriate for repeated accesses like this? >> >> Matthew Kaufman > > Well, I'm interested in such a fast IO access either, but couldn't > find > anything so far... I carried out some experiments and found that the > "regular" approach with opening/writing char dev is indeed very slow, > but I don't understand why. Reniceing didn't help too. Maybe direct > writing into mem/kmem device may work? I haven't try though yet.
you guys probably want interrupt driven gpio. iirc correctly, the Geode gpio subsystem can do that. Someone correct me please if I am wrong, though..... > > Cheers, > Sergey > _______________________________________________ > Soekris-tech mailing list > [email protected] > http://lists.soekris.com/mailman/listinfo/soekris-tech _______________________________________________ Soekris-tech mailing list [email protected] http://lists.soekris.com/mailman/listinfo/soekris-tech
