Re: [PATCH] rtc: Add support for century bits to m41t62 (rv4162) RTC devices

[Lukasz Majewski <lukma@denx.de>]

[-- Attachment #1: Type: text/plain, Size: 1499 bytes --]

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)?


Best regards,

Lukasz Majewski

--

DENX Software Engineering GmbH,      Managing Director: Wolfgang Denk
HRB 165235 Munich, Office: Kirchenstr.5, D-82194 Groebenzell, Germany
Phone: (+49)-8142-66989-59 Fax: (+49)-8142-66989-80 Email: lukma@denx.de

[-- Attachment #2: OpenPGP digital signature --]
[-- Type: application/pgp-signature, Size: 488 bytes --]