On 03/10/2019 15:14:34+0200, Lukasz Majewski wrote: > Hi Alexandre, > > > On 03/10/2019 14:21:50+0200, Lukasz Majewski wrote: > > > > > > > > See the datasheet: > > > > > > > > "During any year which is a multiple of 4, the RV-4162 RTC will > > > > automatically insert leap day, February 29. Therefore, the > > > > application software must correct for this during the exception > > > > years (2100, 2200, etc.) as noted above." > > > > > > I'm wondering what the phrase "application software" means here? > > > > > > If it is the userland SW, then we shall at least be able to set > > > 2099 in this device and then count on software correction. > > > > > > If the "application software" is the kernel driver - the date > > > correction shall be done there (maybe some lookup table?). > > > > > > Personally, I do prefer the first option - this means that with this > > > patch we can set the time to e.g. 2234 year and then rely on > > > userland software (or libc) to do the correction. > > > > > > > It is not possible to ensure this correction is properly done in > > software, there is no point in letting the user set those bits. > > > > > > I see your point. > > However, could you share your idea on testing setting RTC time to year > 2100 on this particular IC (by using hctosys and friends)? > You can use rtc from https://git.kernel.org/pub/scm/linux/kernel/git/abelloni/rtc-tools.git/ You can also use rtc-range with your patch to observe that it fails in 2100. -- Alexandre Belloni, Bootlin Embedded Linux and Kernel engineering https://bootlin.com
