On 10/24/2012 12:10 PM, Kevin Hilman wrote: > From: Kevin Hilman <khilman@xxxxxx> > > When a GPIO bank is freed or shutdown, ensure that the banks > dbck_enable_mask is cleared also. Otherwise, context restore on > subsequent off-mode transition will restore previous value from the > shadow copies (bank->context.debounce*) leading to mismatch state > between driver state and hardware state. > > This was discovered when board code was doing > > gpio_request_one() > gpio_set_debounce() > gpio_free() > > which was leaving the GPIO debounce settings in a confused state. If > that GPIO bank is subsequently used with off-mode enabled, bogus state > would be restored, leaving GPIO debounce enabled which then prevented > the CORE powerdomain from transitioning. > > To fix, ensure that bank->dbck_enable_mask is cleared when the bank > is freed/shutdown so debounce state doesn't persist. > > Special thanks to Grazvydas Ignotas for pointing out a bug in an > earlier version that would've disabled debounce on any runtime PM > transition. > > Reported-by: Paul Walmsley <paul@xxxxxxxxx> > Cc: Igor Grinberg <grinberg@xxxxxxxxxxxxxx> > Cc: Grazvydas Ignotas <notasas@xxxxxxxxx> > Signed-off-by: Kevin Hilman <khilman@xxxxxx> > --- > v2: only clear mask in free/shutdown, not in runtime PM paths, > clarified changelog > Applies on v3.7-rc2. > > drivers/gpio/gpio-omap.c | 1 + > 1 file changed, 1 insertion(+) > > diff --git a/drivers/gpio/gpio-omap.c b/drivers/gpio/gpio-omap.c > index 94cbc84..113b167 100644 > --- a/drivers/gpio/gpio-omap.c > +++ b/drivers/gpio/gpio-omap.c > @@ -539,6 +539,7 @@ static void _reset_gpio(struct gpio_bank *bank, int gpio) > _set_gpio_irqenable(bank, gpio, 0); > _clear_gpio_irqstatus(bank, gpio); > _set_gpio_triggering(bank, GPIO_INDEX(bank, gpio), IRQ_TYPE_NONE); > + bank->dbck_enable_mask = 0; > } Does this need to be ... + bank->dbck_enable_mask &= ~(GPIO_BIT(bank, gpio)); + _gpio_dbck_disable(bank); There could be more than one gpio using debounce and so we should only clear the appropriate bit. Also after clearing a bit we could see if we can disable the debounce clock too. Cheers Jon -- To unsubscribe from this list: send the line "unsubscribe linux-omap" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
