+ Claudiu, Looks RZ/G3S RTC can handle it. ● Periodic interrupt (PRD) ? 2 seconds, 1 second, 1/2 second, 1/4 second, 1/8 second, 1/16 second, 1/32 Cheers, Biju > -----Original Message----- > From: Wolfram Sang <wsa+renesas@xxxxxxxxxxxxxxxxxxxx> > Sent: 25 February 2025 10:19 > To: linux-rtc@xxxxxxxxxxxxxxx; Alexandre Belloni <alexandre.belloni@xxxxxxxxxxx> > Cc: linux-renesas-soc@xxxxxxxxxxxxxxx; Miquel Raynal <miquel.raynal@xxxxxxxxxxx> > Subject: Q: use 1s irqs to overcome alarm minute granularity? > > Hi, > > so alarms of the Renesas RZ-N1 RTC can only have one-minute-granularity. > However, it does have a one-second-interrupt. Has it been tried already for some driver to use such an > interrupt to emulate second-granularity of the alarm? My searches did not yield results so far. > > So the idea is, of course, to the let the alarm fire on the minutes. > Then, enable the second-update irqs until reading the seconds matches the requested seconds of the > alarm. > > It would not only gain us a better resolution for alarms, but also allows for enabling UIE. > > I get it that handling the different interrupts may get tricky if e.g. > there is a change in the timerqueue while something has already been setup or so. I need to research > this, I have currently no idea how this is handled at all. > > But while doing so, I wanted to ask if there are already opinions if this approach is feasible or not. > I can't imagine that I am the first one to try it, so there probably are experiences out there? > > Thanks and happy hacking, > > Wolfram
