On Thu, 24 Sep 2015, Lokesh Vutla wrote: > On Thursday 27 August 2015 09:51 AM, Lokesh Vutla wrote: > > On Thursday 23 July 2015 06:55 PM, Lokesh Vutla wrote: > >> This series implements lock and unlock functions for RTC and hooks > >> the same to DRA7 and AMx3xx hwmod. > >> This is dependent on the patch https://patchwork.kernel.org/patch/6578281/, > >> which is queued recently by Paul. > > Gentle ping on this series. > Do you have any comments on this series? Looks pretty good. I'm slightly concerned about the latency jitter impact on -rt kernels for that local_irq_disable() section. Looks like it could hold off interrupts for ~(50 udelay µs) + 50*((RTC register read time) + 1). But I'm not sure if preempt_enable/disable() is a good alternative since a bunch of interrupt top halves could conceivably run after the RTC goes non-busy and result in the RTC not being locked/unlocked. Is there an RTC IP block register that the code can read, or a safe sequence that the code can execute, after the RTC lock/unlock operation to verify that the RTC has successfully been locked or unlocked? If so then it's probably worth converting the local_irq_disable/enable() to preempt_disable/enable() and testing that, then retrying the lock/unlock if it fails. - Paul
