[RFC 0/5] add rtc support

[Antony Pavlov]

On Fri, 11 Jul 2014 07:37:38 +0200
Sascha Hauer <s.hauer at pengutronix.de> wrote:

> On Thu, Jul 10, 2014 at 12:33:14PM +0400, Antony Pavlov wrote:
> > This patchseries imports RTC support from linux-3.15.
> > 
> > User can use 'hwclock' command to see realtime clock readout.
> > 
> > Tested with DS1307.
> > 
> > TODOs:
> > 
> >  * rtc_set_time() is not realized;
> >  * ds1307_set_time() is not tested;
> >  * bcd lib is compiled in even if rtc support is disabled (as linux does);
> >    we can make it optional;
> 
> It's probably not worth it. The linker will throw it away anyway if
> unused.

Hmm, I have missed this.

In this case can we drop I2C_SMBUS Kconfig stuff

+config I2C_SMBUS
+	bool
+

+obj-$(CONFIG_I2C_SMBUS) += i2c-smbus.o

from 'add driver for PCA95[357]x, ...' series?

Anyway CONFIG_I2C_SMBUS has another meaning in linux.

> 
> >  * adjust include/linux/rtc.h and include/rtc.h;
> >  * rtc_unregister() is not realized.
> 
> Maybe an environment variable which holds the seconds since epoch would
> be useful. This way scripts could make use of the current RTC time.

So you propose to add an option to hwclock command to store RTC readout into variable,
isn't it?

I have an idea to put epoch offset (number of years into AD to which a zero year value
in the Hardware Clock refers) into "global.epoch" variable and add corresponding
Kconfig option for default epoch value.

-- 
Best regards,
  Antony Pavlov