Re: [PATCH 5/5] rtc: sc27xx: Always read normal alarm when registering RTC device
From: Alexandre Belloni
Date: Wed Oct 24 2018 - 20:35:01 EST
On 18/10/2018 16:52:30+0800, Baolin Wang wrote:
> When registering one RTC device, it will check to see if there is an
> alarm already set in RTC hardware by reading RTC alarm, at this time
> we should always read the normal alarm put in always-on region by
> checking the rtc->registered flag.
> Signed-off-by: Baolin Wang <baolin.wang@xxxxxxxxxx>
> drivers/rtc/rtc-sc27xx.c | 8 ++++++--
> 1 file changed, 6 insertions(+), 2 deletions(-)
> diff --git a/drivers/rtc/rtc-sc27xx.c b/drivers/rtc/rtc-sc27xx.c
> index 72bb002..b4eb3b3 100644
> --- a/drivers/rtc/rtc-sc27xx.c
> +++ b/drivers/rtc/rtc-sc27xx.c
> @@ -415,10 +415,14 @@ static int sprd_rtc_read_alarm(struct device *dev, struct rtc_wkalrm *alrm)
> u32 val;
> - * If aie_timer is enabled, we should get the normal alarm time.
> + * Before RTC device is registered, it will check to see if there is an
> + * alarm already set in RTC hardware, and we always read the normal
> + * alarm at this time.
> + *
> + * Or if aie_timer is enabled, we should get the normal alarm time.
> * Otherwise we should get auxiliary alarm time.
> - if (rtc->rtc && rtc->rtc->aie_timer.enabled == 0)
> + if (rtc->rtc && rtc->rtc->registered && rtc->rtc->aie_timer.enabled == 0)
Note that the driver should not access rtc->registered and
rtc->aie_timer.enabled and this is a bit fragile.
But, on the other hand, I currently don't have anything better to
suggest. I was also planning to add an in-kernel API for multiple alarms
but I'm not sure it will actually help in your case.
Anyway, this is applied.
Alexandre Belloni, Bootlin
Embedded Linux and Kernel engineering