Rk808 has a under voltage detect function, when the voltage of buck is
under 85% the target voltage, the buck output will reset. But if the
power load is too heavy, this function maybe err, when current over
4.2A, although the voltage is normal, but RK808 mistakenly think it is
under 85%, and reset the buck. So let's disable this function.
Signed-off-by: NChris Zhong <zyw@rock-chips.com>
Signed-off-by: NLee Jones <lee.jones@linaro.org>

Let's define the voltatile registers (those that can't be cached) and
enable caching.  The rk808 is accessed almost constantly with cpufreq
so this is really nice.

As measured by ftrace:
  before this change: cpu0_set_target() => ~2200us
  after this change:  cpu0_set_target() =>  ~500us
Signed-off-by: NDoug Anderson <dianders@chromium.org>
Reviewed-by: NChris Zhong <zyw@rock-chips.com>
Signed-off-by: NLee Jones <lee.jones@linaro.org>

The RK808 chip is a power management IC for multimedia and handheld
devices. It contains the following components:

- Regulators
- RTC
- Clkout

The RK808 core driver is registered as a platform driver and provides
communication through I2C with the host device for the different
components.
Signed-off-by: NChris Zhong <zyw@rock-chips.com>
Signed-off-by: NZhang Qing <zhangqing@rock-chips.com>
Tested-by: NHeiko <heiko@sntech.de>
Signed-off-by: NLee Jones <lee.jones@linaro.org>