After we set the GET_TIME bit, the rtc time can't be read immediately.  We
should wait up to 31.25 us, about one cycle of 32khz.  Otherwise reading
RTC time will return a old time.  If we clear the GET_TIME bit after
setting, the time of i2c transfer is certainly more than 31.25us.

Doug said:

: I think we are safe.  At 400kHz (the max speed of this part) each bit can
: be transferred no faster than 2.5us.  In order to do a valid i2c
: transaction we need to _at least_ write the address of the device and the
: data onto the bus, which is 16 bits.  16 * 2.5us = 40us.  That's above the
: 31.25us

[akpm@linux-foundation.org: tweak comment per review discussion]
Signed-off-by: NChris Zhong <zyw@rock-chips.com>
Reviewed-by: NDoug Anderson <dianders@chromium.org>
Cc: Sonny Rao <sonnyrao@chromium.org>
Cc: Heiko Stübner <heiko@sntech.de>
Cc: Alessandro Zummo <a.zummo@towertech.it>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

This is the initial version of the RK808 PMIC.  This is a power management
IC for multimedia products.  It provides regulators that are able to
supply power to processor cores and other components.  The chip provides
other modules including RTC, Clockout.

Add RTC driver for supporting RTC device present inside RK808 PMIC.

[akpm@linux-foundation.org: make tm_def static]
Signed-off-by: NChris Zhong <zyw@rock-chips.com>
Signed-off-by: NZhang Qing <zhangqing@rock-chips.com>
Tested-by: NHeiko Stuebner <heiko@sntech.de>
Reviewed-by: NDoug Anderson <dianders@chromium.org>
Tested-by: NDoug Anderson <dianders@chromium.org>
Cc: Pawel Moll <pawel.moll@arm.com>
Cc: Mark Rutland <mark.rutland@arm.com>
Cc: Ian Campbell <ijc+devicetree@hellion.org.uk>
Cc: Samuel Ortiz <sameo@linux.intel.com> says:
Cc: Alessandro Zummo <a.zummo@towertech.it>
Cc: Olof Johansson <olof@lixom.net>
Cc: Dmitry Torokhov <dtor@chromium.org>
Cc: Javier Martinez Canillas <javier.martinez@collabora.co.uk>
Cc: Kever Yang <kever.yang@rock-chips.com>
Cc: Li Zhong <zhong@linux.vnet.ibm.com>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>