The RTC controls the input source of the main 32kHz oscillator in the
system, feeding it to the clock unit too.
By default, this is using an internal, very inaccurate (+/- 30%)
oscillator with a divider to make it roughly around 32kHz. This is however
quite impractical for the RTC, since our time will not be tracked properly.
Since this oscillator is an input of the main clock unit, and since that
clock unit will be probed using CLK_OF_DECLARE, we have to use it as well,
leading to a two stage probe: one to enable the clock, the other one to
enable the RTC.
There is also a slight change in the binding that is required (and should
have been from the beginning), since we'll need a phandle to the external
oscillator used on that board. We support the old binding by not allowing
to switch to the external oscillator and only using the internal one (which
was the previous behaviour) in the case where we're missing that phandle.
Signed-off-by: Maxime Ripard <maxime.ripard@free-electrons.com>
Acked-by: Rob Herring <robh@kernel.org>
Signed-off-by: Alexandre Belloni <alexandre.belloni@free-electrons.com>
This patch introduces the driver for the RTC in the Allwinner A31 and
A23 SoCs.
Unlike the RTC found in A10/A20 SoCs, which was part of the timer, the
RTC in A31/A23 are a separate hardware block, which also contain a few
controls for the RTC block hardware (a regulator and RTC block GPIO pin
latches), while also having separate interrupts for the alarms.
The hardware is different enough to make a different driver for it.
Signed-off-by: Chen-Yu Tsai <wens@csie.org>
Reviewed-by: Varka Bhadram <varkabhadram@gmail.com>
Signed-off-by: Maxime Ripard <maxime.ripard@free-electrons.com>
