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authorKevin Hilman <khilman@ti.com>2012-03-05 15:10:04 -0800
committerGrant Likely <grant.likely@secretlab.ca>2012-03-12 10:16:11 -0600
commit68942edb09f69b6e09522d1d346665eb3aadde49 (patch)
treed274bac19fdd5c0c46a67e8410960a16bf0c205a /drivers/gpio/gpio-lpc32xx.c
parente2aa4177264c1a459779d6e35fae22adf17a9232 (diff)
gpio/omap: fix wakeups on level-triggered GPIOs
While both level- and edge-triggered GPIOs are capable of generating interrupts, only edge-triggered GPIOs are capable of generating a module-level wakeup to the PRCM (c.f. 34xx NDA TRM section 25.5.3.2.) In order to ensure that devices using level-triggered GPIOs as interrupts can also cause wakeups (e.g. from idle), this patch enables edge-triggering for wakeup-enabled, level-triggered GPIOs when a GPIO bank is runtime-suspended (which also happens during idle.) This fixes a problem found in GPMC-connected network cards with GPIO interrupts (e.g. smsc911x on Zoom3, Overo, ...) where network booting with NFSroot was very slow since the GPIO IRQs used by the NIC were not generating PRCM wakeups, and thus not waking the system from idle. NOTE: until v3.3, this boot-time problem was somewhat masked because the UART init prevented WFI during boot until the full serial driver was available. Preventing WFI allowed regular GPIO interrupts to fire and this problem was not seen. After the UART runtime PM cleanups, we no longer avoid WFI during boot, so GPIO IRQs that were not causing wakeups resulted in very slow IRQ response times. Tested on platforms using level-triggered GPIOs for network IRQs using the SMSC911x NIC: 3530/Overo and 3630/Zoom3. Reported-by: Tony Lindgren <tony@atomide.com> Tested-by: Tarun Kanti DebBarma <tarun.kanti@ti.com> Tested-by: Tony Lindgren <tony@atomide.com> Signed-off-by: Kevin Hilman <khilman@ti.com> Signed-off-by: Grant Likely <grant.likely@secretlab.ca>
Diffstat (limited to 'drivers/gpio/gpio-lpc32xx.c')
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