Messages in this thread | | | Subject | Re: [RFC PATCH] watchdog: da9062: Correct the timeout values [Klartext] | From | Andrej Picej <> | Date | Mon, 13 Dec 2021 15:31:22 +0100 |
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On 13. 12. 21 10:11, Christoph Niedermaier wrote: > Resend with [Klartext] to turn off TLS encryption. > > From: Adam Thomson > Sent: Monday, December 6, 2021 5:38 PM >>> Thanks anyway, so now I know it must be >>> problem with my DA9061 chip. >>> >>> @Adam >>> Where can it come from? >>> Can you give we a hint what to check? >> >> I've spoken internally and have been informed that this is down to the fact that >> DA9061 runs only from an internal oscillator which may be slower. The indication >> is that the values for TWDSCALE describe the window where if a kick/ping occurs >> within that period then the watchdog is guaranteed *not* to timeout. The actual >> timeout would be at some point after the selected timeout period, assuming no >> ping/kick occurred. >> >> Table 8 in the datasheet specifies a minimum watchdog timeout of 2.5s (tWDMAX) >> under specific operating conditions, so if the minimum 2s window was chosen >> (TWDSCALE = 1) then earliest the watchdog would actually timeout, following a >> ping, is 2.5s, assuming the conditions matched those described. >> >> If you have further questions it probably makes sense to contact Dialog/Renesas >> support as they will be able to provide more detailed info on this. > > So a DA9061 runs only from an internal oscillator, whereas a DA9062 > can run on either an internal or an external oscillator. So this > means that the DA9061 timeout values are differ from the DA9062 > with an external oscillator not only on my device but on all DA9061 > devices. > > This are the values (in seconds) in comparison: > DA9062 (from driver): 0 2 4 8 16 32 65 131 > DA9061 (measured): 0 3 6 12 25 51 102 204 > ================================================= > Difference: 0 +1 +2 +4 +9 +19 +37 +73 > > In my opinion, the differences in the higher values are very huge. > If I expect that the watchdog triggers and I have to wait more than > a minute for that to happen I ask myself is there something wrong. > > @Andrej > I guess, you are using an external oscillator, aren't you?
You are correct, we are using external oscillator (32,768KHz).
> > @Adam > Is there a way to check in the driver which oscillator is in use? > > @Maintainers > Is in the driver a need to distinguish between an external and an > internal oscillator to get the timeout values more accurate? > > > Best regards > Christoph >
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