On Fri, 31 May 2013 15:37:07 -0700 Kevin Hilman <khil...@linaro.org> wrote:
> Currently, the RTC IRQ is never wakeup-enabled so is not capable of
> bringing the system out of suspend.
>
> On OMAP platforms, we have gotten by without this because the TWL RTC
> is on an I2C-connected chip which is capable of waking up the OMAP via
> the IO ring when the OMAP is in low-power states.
>
> However, if the OMAP suspends without hitting the low-power states
> (and the IO ring is not enabled), RTC wakeups will not work because
> the IRQ is not wakeup enabled.
>
> To fix, ensure the RTC IRQ is wakeup enabled whenever the RTC alarm is
> set.
>
> --- a/drivers/rtc/rtc-twl.c
> +++ b/drivers/rtc/rtc-twl.c
> @@ -213,12 +213,24 @@ static int mask_rtc_irq_bit(unsigned char bit)
>
> static int twl_rtc_alarm_irq_enable(struct device *dev, unsigned enabled)
> {
> + struct platform_device *pdev = to_platform_device(dev);
> + int irq = platform_get_irq(pdev, 0);
> + static bool twl_rtc_wake_enabled;
> int ret;
>
> - if (enabled)
> + if (enabled) {
> ret = set_rtc_irq_bit(BIT_RTC_INTERRUPTS_REG_IT_ALARM_M);
> - else
> + if (device_can_wakeup(dev) && !twl_rtc_wake_enabled) {
> + enable_irq_wake(irq);
> + twl_rtc_wake_enabled = true;
> + }
> + } else {
> ret = mask_rtc_irq_bit(BIT_RTC_INTERRUPTS_REG_IT_ALARM_M);
> + if (twl_rtc_wake_enabled) {
> + disable_irq_wake(irq);
> + twl_rtc_wake_enabled = false;
> + }
> + }
Why do we need this (slightly racy) logic with twl_rtc_wake_enabled?
Other drivers don't do this.
Should we test device_may_wakeup() befre running disable_irq_wake()?
Most drivers seem to do this, but it's all a bit foggy.
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