[systemd-devel] RTC on BeagleBone Black or embedded platforms

Kay Sievers kay at vrfy.org
Thu Feb 27 09:38:38 PST 2014

On Thu, Feb 27, 2014 at 4:46 PM, Mike <bellyacres at gmail.com> wrote:

> My biggest dilemma at this time right now is with the RTC.  The BeagleBone
> Black does have a RTC and it gets assigned to /dev/rtc0. There is however
> now battery backup for this device.

Assuming you meant "no"?

> I've added a DS1307 with a battery to
> allow having a somewhat sane date maintained.  Therein lies the dilemma, the
> code is only setup to access /dev/rtc.  I'm sure that I can figure out with
> a (gasp) shell script or small c program how to set / get the date from the
> DS1307, it just seems that would be a very crude kludge.

Can't you set the kernel config to use the new clock as the system
rtc? It's a kernel config option.

Can't you write a udev rule that creates /dev/rtc for your new clock?
That should be picked up from userspace, but userspace does not do the
initial sync from the hardware to the system, we only do that in the
kernel so far.


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