tree 6d7cff550c155d8140fa8c7c332c899f2426d5ff
parent 8cbef2da2479129d2a3ae98a3ccc64fb1fec1d26
author Krzysztof Chruscinski <krzysztof.chruscinski@nordicsemi.no> 1626675225 +0200
committer Carles Cufí <carles.cufi@nordicsemi.no> 1626688947 +0200

drivers: timer: nrf_rtc_timer: Fix race condition

RTC interrupt was reading CC value and passing it to the handler.
However, higher priority interrupt could preempt RTC interrupt
and set new CC value. In that case CC value read in the RTC
interrupt context was not the one that triggered the interrupt.
Added fallback to COUNTER value if that case is detected.

Using COUNTER is not as precise as CC because it returns time
when event was handled and not when event occured but it is the
only option since CC value is overwritten.

Signed-off-by: Krzysztof Chruscinski <krzysztof.chruscinski@nordicsemi.no>