Sigh. Yea, this issue was brought up previously, but we never got
around to a solution that could be merged.
Basically hctosys is late_init, but if the driver is a module, it
might not be loaded in time. Adding hooks at module load time when
RTCs are registered could be done, but then you have the issue that
userspace might have set the clock via something like ntpdate, so
HCTOSYS could then cause the clock to be less accurate.
So we need to make the HCTOSYS functionality happen at RTC register
time, but it needs to set the clock only if nothing has set the clock
already. This requires a new timekeeeping interface - something like
timekeeping_set_time_if_unset(), which atomically would set the time
if it has never been set.
You can read some of the previous discussion here:
https://lkml.org/lkml/2013/6/17/533
I'd be very interested in patches to resolve this!