Currently, the RTC code does not disable the alarm in the hardware.

This means that after a sequence such as the one below (the files are in the
RTC sysfs), the box will boot up after 2 minutes even though we've
asked for the alarm to be turned off.

	# echo $((`cat since_epoch`)+120) > wakealarm
	# echo 0 > wakealarm
	# poweroff

Fix this by disabling the alarm when there are no timers to run.

Cc: stable@kernel.org
Cc: John Stultz <john.stultz@linaro.org>
Signed-off-by: NRabin Vincent <rabin.vincent@stericsson.com>
Signed-off-by: NJohn Stultz <john.stultz@linaro.org>

As the comment explains, the intention of the code is to clear the
OMAP_RTC_CTRL_MODE_12_24 bit, but instead it only clears the
OMAP_RTC_CTRL_SPLIT and OMAP_RTC_CTRL_AUTO_COMP bits, which should be
kept.  OMAP_RTC_CTRL_DISABLE, OMAP_RTC_CTRL_SET_32_COUNTER,
OMAP_RTC_CTRL_TEST, and OMAP_RTC_CTRL_ROUND_30S are also better off
being cleared.
Signed-off-by: NDaniel Glöckner <dg@emlix.com>
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>

Ben reported a lockup related to rtc. The lockup happens due to:

CPU0                                        CPU1

rtc_irq_set_state()			    __run_hrtimer()
  spin_lock_irqsave(&rtc->irq_task_lock)    rtc_handle_legacy_irq();
					      spin_lock(&rtc->irq_task_lock);
  hrtimer_cancel()
    while (callback_running);

So the running callback never finishes as it's blocked on
rtc->irq_task_lock.

Use hrtimer_try_to_cancel() instead and drop rtc->irq_task_lock while
waiting for the callback.  Fix this for both rtc_irq_set_state() and
rtc_irq_set_freq().
Signed-off-by: NThomas Gleixner <tglx@linutronix.de>
Reported-by: NBen Greear <greearb@candelatech.com>
Cc: John Stultz <john.stultz@linaro.org>
Cc: Ingo Molnar <mingo@elte.hu>
Cc: <stable@kernel.org>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

Due to the hrtimer self rearming mode a user can DoS the machine simply
because it's starved by hrtimer events.

The RTC hrtimer is self rearming.  We really need to limit the frequency
to something sensible.
Signed-off-by: NThomas Gleixner <tglx@linutronix.de>
Cc: John Stultz <john.stultz@linaro.org>
Cc: Ingo Molnar <mingo@elte.hu>
Cc: Ben Greear <greearb@candelatech.com>
Cc: <stable@kernel.org>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

The code checks the correctness of the parameters, but unconditionally
arms/disarms the hrtimer.

The result is that a random task might arm/disarm rtc timer and surprise
the real owner by either generating events or by stopping them.
Signed-off-by: NThomas Gleixner <tglx@linutronix.de>
Cc: John Stultz <john.stultz@linaro.org>
Cc: Ingo Molnar <mingo@elte.hu>
Cc: Ben Greear <greearb@candelatech.com>
Cc: <stable@kernel.org>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

Using __SPIN_LOCK_UNLOCKED for a dynamically allocated lock is wrong and
breaks the build with PREEMPT_RT_FULL.
Signed-off-by: NUwe Kleine-König <u.kleine-koenig@pengutronix.de>
Cc: Andrew Chew <achew@nvidia.com>
Cc: <stable@kernel.org>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

We forget to save the return value of the call to
twl_rtc_write_u8(save_control, REG_RTC_CTRL_REG); in 'ret', making the
test of 'ret < 0' dead code since 'ret' then couldn't possibly have
changed since the last test just a few lines above.  It also makes us not
detect failures from that specific twl_rtc_write_u8() call.
Signed-off-by: NJesper Juhl <jj@chaosbits.net>
Cc: Alessandro Zummo <a.zummo@towertech.it>
Cc: Alexandre Rusev <source@mvista.com>
Cc: "George G. Davis" <gdavis@mvista.com>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

Add support for PMIC8xxx based RTC.  PMIC8xxx is Qualcomm's power
management IC that internally houses an RTC module.  This driver
communicates with the PMIC module over SSBI bus.

[akpm@linux-foundation.org: cosmetic tweaks]
Acked-by: NWan ZongShun <mcuos.com@gmail.com>
Reviewed-by: NStephen Boyd <sboyd@codeaurora.org>
Signed-off-by: NAnirudh Ghayal <aghayal@codeaurora.org>
Signed-off-by: NAshay Jaiswal <ashayj@codeaurora.org>
Cc: Samuel Ortiz <sameo@linux.intel.com>
Cc: Wan ZongShun <mcuos.com@gmail.com>
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>

Add support for clock gating.  Power consumption can be reduced by setting
rtc_clk disabled state except for when RTC related registers are accessed.
Signed-off-by: NDonggeun Kim <dg77.kim@samsung.com>
Signed-off-by: NMyungJoo Ham <myungjoo.ham@samsung.com>
Signed-off-by: NKyungMin Park <kyungmin.park@samsung.com>
Cc: Alessandro Zummo <a.zummo@towertech.it>
Cc: Ben Dooks <ben@fluff.org>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

MPC5200B contains a limited version of RTC from MPC5121.  Add support for
the RTC on that CPU.
Signed-off-by: NDmitry Eremin-Solenikov <dbaryshkov@gmail.com>
Cc: Alessandro Zummo <a.zummo@towertech.it>
Cc: Anatolij Gustschin <agust@denx.de>
Cc: Grant Likely <grant.likely@secretlab.ca>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

The RTC core handles UIE since 6610e089 (RTC: Rework RTC code to use
timerqueue for events), so remove the specific interrupt in this driver.
To make it work at all, enable interrupts in set_alarm() if needed. Drop
IRQF_DISABLED which is deprecated, while we are here.  Finally, add my
copyright after all these changes.
Signed-off-by: NWolfram Sang <w.sang@pengutronix.de>
Tested-by: NShawn Guo <shawn.guo@freescale.com>
Signed-off-by: NJohn Stultz <john.stultz@linaro.org>

Replace the accessors with standard readl/writel to remove their
platform-dependency. Also, drop __raw_(read|write)l-accessors while we
are here.
Signed-off-by: NWolfram Sang <w.sang@pengutronix.de>
Tested-by: NShawn Guo <shawn.guo@freescale.com>
Signed-off-by: NJohn Stultz <john.stultz@linaro.org>

Commit f44f7f96 ("RTC: Initialize kernel state from RTC") uncovered
an issue in a number of RTC drivers, where the drivers call
rtc_device_register before initializing the device or platform drvdata.

This frequently results in null pointer dereferences when the
rtc_device_register immediately makes use of the rtc device, calling
rtc_read_alarm.

The solution is to ensure the drvdata is initialized prior to registering
the rtc device.
Signed-off-by: NWolfram Sang <w.sang@pengutronix.de>
Tested-by: NShawn Guo <shawn.guo@freescale.com>
Signed-off-by: NJohn Stultz <john.stultz@linaro.org>

The stmp3xxx  driver used to include functions from a stmp-specific
include. Because of consolidation, plat-stmp has now been removed and
merged with the compatible mach-mxs.

Use the apropriate mxs-functions for transition. The accessors will be
converted to readl/writel in a later patch.
Signed-off-by: NWolfram Sang <w.sang@pengutronix.de>
Tested-by: NShawn Guo <shawn.guo@freescale.com>
Signed-off-by: NJohn Stultz <john.stultz@linaro.org>

The stmp3xxx driver used to include register names from a stmp-specific
include. Because of consolidation, plat-stmp has now been removed and
merged with the compatible mach-mxs. Restore the register names directly
in the driver and rename them to be specific to this driver.
Signed-off-by: NWolfram Sang <w.sang@pengutronix.de>
Tested-by: NShawn Guo <shawn.guo@freescale.com>
Signed-off-by: NJohn Stultz <john.stultz@linaro.org>

Fixes the vt8500 driver to use a define value for the isr
is-alarm bit.

Cc: Alexey Charkov <alchark@gmail.com>
Signed-off-by: NWolfram Sang <w.sang@pengutronix.de>
Signed-off-by: NJohn Stultz <john.stultz@linaro.org>

PT7C4338 chip is being manufactured by Pericom Technology Inc.  It is a
serial real-time clock which provides:

1) Low-power clock/calendar.
2) Programmable square-wave output.

It has 56 bytes of nonvolatile RAM.  Its register set is same as that of
rtc device: DS1307.
Signed-off-by: NPriyanka Jain <Priyanka.Jain@freescale.com>
Acked-by: NTimur Tabi <timur@freescale.com>
Reviewed-by: NWolfram Sang <w.sang@pengutronix.de>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

Now that the generic code handles UIE mode irqs via periodic
alarm interrupts, no one calls the
rtc_class_ops->update_irq_enable() method anymore.

Further the rtc_class_ops doesn't have a update_irq_enable element
anymore, so this causes a build error.

This patch removes the driver hooks and implementations of
update_irq_enable and the associated setup.

[wsa: updated commit-message and removed update_irq_enable-function, too]
[jstultz: improve commit message, clarifying build issue]
Signed-off-by: NAlexey Charkov <alchark@gmail.com>
Signed-off-by: NWolfram Sang <w.sang@pengutronix.de>
Signed-off-by: NJohn Stultz <john.stultz@linaro.org>

Because the RTC interface is only a second granular interface,
each time we read from the RTC for suspend/resume, we introduce a
half second (on average) of error.

In order to avoid this error accumulating as the system is suspended
over and over, this patch measures the time delta between the RTC
and the system CLOCK_REALTIME.

If the delta is less then 2 seconds from the last suspend, we compensate
by using the previous time delta (keeping it close). If it is larger
then 2 seconds, we assume the clock was set or has been changed, so we
do no correction and update the delta.

Note: If NTP is running, ths could seem to "fight" with the NTP corrected
time, where as if the system time was off by 1 second, and NTP slewed the
value in, a suspend/resume cycle could undo this correction, by trying to
restore the previous offset from the RTC. However, without this patch,
since each read could cause almost a full second worth of error, its
possible to get almost 2 seconds of error just from the suspend/resume
cycle alone, so this about equal to any offset added by the compensation.

Further on systems that suspend/resume frequently, this should keep time
closer then NTP could compensate for if the errors were allowed to
accumulate.

Credits to Arve Hjønnevåg for suggesting this solution.

This patch also improves some of the variable names and adds more clear
comments.

CC: Arve Hjønnevåg <arve@android.com>
CC: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: NJohn Stultz <john.stultz@linaro.org>

Several fixes as well where the +1 was missing.

Done via coccinelle scripts like:

@@
struct resource *ptr;
@@

- ptr->end - ptr->start + 1
+ resource_size(ptr)

and some grep and typing.

Mostly uncompiled, no cross-compilers.
Signed-off-by: NJoe Perches <joe@perches.com>
Signed-off-by: NJiri Kosina <jkosina@suse.cz>

The patch moves rtc driver for PKUnity-v3 SoC from arch/unicore32/kernel/
to drivers/rtc/, with renaming it to rtc-puv3.c.
Also, Kconfig, Makefile, and MAINTAINERS are modified correspondingly.
Signed-off-by: NGuan Xuetao <gxt@mprc.pku.edu.cn>
Acked-by: NArnd Bergmann <arnd@arndb.de>

One new offender detected by the recently increased type checking in
platform_get_drvdata():

drivers/rtc/rtc-m41t93.c: In function ‘m41t93_remove’:
drivers/rtc/rtc-m41t93.c:192: warning: passing argument 1 of ‘platform_get_drvdata’ from incompatible pointer type

Use spi_get_drvdata() instead of platform_get_drvdata(), cfr. commit
42fea15d ("spi/rtc-{ds1390,ds3234,m41t94}:
Use spi_get_drvdata() for SPI devices")
Signed-off-by: NGeert Uytterhoeven <geert@linux-m68k.org>
Signed-off-by: NGrant Likely <grant.likely@secretlab.ca>

It's not referenced outside this file so there's no need for it to be in
the global namespace and sparse warns about that.
Signed-off-by: NMark Brown <broonie@opensource.wolfsonmicro.com>
Signed-off-by: NJohn Stultz <john.stultz@linaro.org>

Bryan Henderson noticed that the  "RTC: Fix rtc driver ioctl specific
shortcutting" commit has a small bug: When an ioctl is called with an
invalid command code and the clock driver does not have an "ioctl"
method, the ioctl returns rc 0 instead of -ENOTTY.

This patch fixes the issue.

CC: Bryan Henderson <bryanh@giraffe-data.com>
CC: Gabor Z. Papp <gzp@papp.hu>
Reported-by: NBryan Henderson <bryanh@giraffe-data.com>
Signed-off-by: NJohn Stultz <john.stultz@linaro.org>

[akpm@linux-foundation.org: retain the code comments]
Signed-off-by: NWolfram Sang <w.sang@pengutronix.de>
Cc: Vladimir Zapolskiy <vzapolskiy@gmail.com>
Cc: Alessandro Zummo <alessandro.zummo@towertech.it>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

Commit 51ba60c5 ("RTC: Cleanup rtc_class_ops->update_irq_enable()")
removed the only user of the update IRQ, so there is no need to manage it
any more.
Signed-off-by: NLars-Peter Clausen <lars@metafoo.de>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Alessandro Zummo <a.zummo@towertech.it>
Cc: Marcelo Roberto Jimenez <mroberto@cpti.cetuc.puc-rio.br>
Cc: John Stultz <john.stultz@linaro.org>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

Signed-off-by: NRajeev Kumar <rajeev-dlh.kumar@st.com>
Signed-off-by: NViresh Kumar <viresh.kumar@st.com>
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>

The memory allocated using request_mem_region should be released using
release_mem_region, not release_region.

The semantic patch that fixes part of this problem is as follows:
(http://coccinelle.lip6.fr/)

  // <smpl>
  @@
  expression E1,E2,E3;
  @@

  request_mem_region(E1,E2,E3)
  ...
  ?- release_region(E1,E2)
  + release_mem_region(E1,E2)
  // </smpl>

[akpm@linux-foundation.org: use resource_size()]
Signed-off-by: NJulia Lawall <julia@diku.dk>
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>

Add basic support for ST m41t93 SPI RTCs.  Tested with factory-new and
with "run-in" species with and without backup batteries.
Signed-off-by: NNikolaus Voss <n.voss@weinmann.de>
Cc: Alessandro Zummo <a.zummo@towertech.it>
Cc: Grant Likely <grant.likely@secretlab.ca>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

Add support for the Micro Crystal RV3029-C2 RTC chips.
Signed-off-by: NHeiko Schocher <hs@denx.de>
Signed-off-by: NGregory Hermant <gregory.hermant@calao-systems.com>
Cc: Wan ZongShun <mcuos.com@gmail.com>
Cc: Alessandro Zummo <a.zummo@towertech.it>
Acked-by: NWolfram Sang <w.sang@pengutronix.de>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

Add support for EM Microelectronic EM3027 RTC chip.
Signed-off-by: NMike Rapoport <mike@compulab.co.il>
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 adds a driver for the RTC devices in VIA and WonderMedia
Systems-on-Chip.  Alarm, 1Hz interrupts, reading and setting time are
supported.
Signed-off-by: NAlexey Charkov <alchark@gmail.com>
Cc: Lars-Peter Clausen <lars@metafoo.de>
Cc: Alexey Charkov <alchark@gmail.com>
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>

Enable rtc function in 88pm860x PMIC.
Signed-off-by: NHaojian Zhuang <haojian.zhuang@marvell.com>
Cc: Alessandro Zummo <a.zummo@towertech.it>
Signed-off-by: NSamuel Ortiz <sameo@linux.intel.com>

This is a simple RTC driver that lets Tilera hardware boot up and
set the clock correctly.
Acked-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NChris Metcalf <cmetcalf@tilera.com>

The driver is not balancing set_irq and disable_irq_wake() calls, so
ensure that it keeps track of whether the wake is enabled.

The fixes the following error on S3C6410 devices:

  WARNING: at kernel/irq/manage.c:382 set_irq_wake+0x84/0xec()
  Unbalanced IRQ 92 wake disable
Signed-off-by: NBen Dooks <ben-linux@fluff.org>
Signed-off-by: NMark Brown <broonie@opensource.wolfsonmicro.com>
Cc: Alessandro Zummo <a.zummo@towertech.it>
Cc: <stable@kernel.org>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

Since commit f44f7f96 (RTC: Initialize kernel state from RTC)
rtc_device_register reads the programmed alarm. As reading the alarm
needs to take the mc13xxx lock, release it before calling
rtc_device_register.

This fixes a deadlock during boot:

	INFO: task swapper:1 blocked for more than 120 seconds.
	"echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
	swapper         D c02b175c     0     1      0 0x00000000
	[<c02b175c>] (schedule+0x304/0x4f4) from [<c02b25a8>] (__mutex_lock_slowpath+0x7c/0x110)
	[<c02b25a8>] (__mutex_lock_slowpath+0x7c/0x110) from [<c020b4cc>] (mc13xxx_rtc_read_time+0x1c/0x118)
	[<c020b4cc>] (mc13xxx_rtc_read_time+0x1c/0x118) from [<c0208f04>] (__rtc_read_time+0x58/0x5c)
	[<c0208f04>] (__rtc_read_time+0x58/0x5c) from [<c0209508>] (rtc_read_time+0x30/0x48)
	[<c0209508>] (rtc_read_time+0x30/0x48) from [<c0209dd4>] (__rtc_read_alarm+0x1c/0x290)
	[<c0209dd4>] (__rtc_read_alarm+0x1c/0x290) from [<c0208d58>] (rtc_device_register+0x150/0x27c)
	[<c0208d58>] (rtc_device_register+0x150/0x27c) from [<c02b0b74>] (mc13xxx_rtc_probe+0x128/0x17c)
	[<c02b0b74>] (mc13xxx_rtc_probe+0x128/0x17c) from [<c01d5280>] (platform_drv_probe+0x1c/0x24)
	[<c01d5280>] (platform_drv_probe+0x1c/0x24) from [<c01d3e58>] (driver_probe_device+0x80/0x1a8)
	[<c01d3e58>] (driver_probe_device+0x80/0x1a8) from [<c01d400c>] (__driver_attach+0x8c/0x90)
	[<c01d400c>] (__driver_attach+0x8c/0x90) from [<c01d3654>] (bus_for_each_dev+0x60/0x8c)
	[<c01d3654>] (bus_for_each_dev+0x60/0x8c) from [<c01d2f6c>] (bus_add_driver+0x180/0x248)
	[<c01d2f6c>] (bus_add_driver+0x180/0x248) from [<c01d4664>] (driver_register+0x70/0x15c)
	[<c01d4664>] (driver_register+0x70/0x15c) from [<c01d5700>] (platform_driver_probe+0x18/0x98)
	[<c01d5700>] (platform_driver_probe+0x18/0x98) from [<c00273a8>] (do_one_initcall+0x2c/0x168)
	[<c00273a8>] (do_one_initcall+0x2c/0x168) from [<c00083ac>] (kernel_init+0xa0/0x150)
	[<c00083ac>] (kernel_init+0xa0/0x150) from [<c0033ff8>] (kernel_thread_exit+0x0/0x8)
Reported-by: NVagrant Cascadian <vagrant@debian.org>
Signed-off-by: NUwe Kleine-König <u.kleine-koenig@pengutronix.de>
Closes: http://bugs.debian.org/625804
[Tweaked commit log -jstultz]
Signed-off-by: NJohn Stultz <john.stultz@linaro.org>

Commit f44f7f96 ("RTC: Initialize kernel state from RTC") uncovered
an issue in a number of RTC drivers, where the drivers call
rtc_device_register before initializing the device or platform drvdata.

This frequently results in null pointer dereferences when the
rtc_device_register immediately makes use of the rtc device, calling
rtc_read_alarm.

The solution is to ensure the drvdata is initialized prior to registering
the rtc device.

CC: Wolfram Sang <w.sang@pengutronix.de>
CC: Alessandro Zummo <a.zummo@towertech.it>
CC: Thomas Gleixner <tglx@linutronix.de>
CC: rtc-linux@googlegroups.com
Signed-off-by: NJohn Stultz <john.stultz@linaro.org>

Commit f44f7f96 ("RTC: Initialize kernel state from RTC") uncovered
an issue in a number of RTC drivers, where the drivers call
rtc_device_register before initializing the device or platform drvdata.

This frequently results in null pointer dereferences when the
rtc_device_register immediately makes use of the rtc device, calling
rtc_read_alarm.

The solution is to ensure the drvdata is initialized prior to registering
the rtc device.

CC: Wolfram Sang <w.sang@pengutronix.de>
CC: Alessandro Zummo <a.zummo@towertech.it>
CC: Thomas Gleixner <tglx@linutronix.de>
CC: rtc-linux@googlegroups.com
Signed-off-by: NJohn Stultz <john.stultz@linaro.org>

Commit f44f7f96 ("RTC: Initialize kernel state from RTC") uncovered
an issue in a number of RTC drivers, where the drivers call
rtc_device_register before initializing the device or platform drvdata.

This frequently results in null pointer dereferences when the
rtc_device_register immediately makes use of the rtc device, calling
rtc_read_alarm.

The solution is to ensure the drvdata is initialized prior to registering
the rtc device.

CC: Wolfram Sang <w.sang@pengutronix.de>
CC: Alessandro Zummo <a.zummo@towertech.it>
CC: Thomas Gleixner <tglx@linutronix.de>
CC: rtc-linux@googlegroups.com
Signed-off-by: NJohn Stultz <john.stultz@linaro.org>

Commit f44f7f96 ("RTC: Initialize kernel state from RTC") uncovered
an issue in a number of RTC drivers, where the drivers call
rtc_device_register before initializing the device or platform drvdata.

This frequently results in null pointer dereferences when the
rtc_device_register immediately makes use of the rtc device, calling
rtc_read_alarm.

The solution is to ensure the drvdata is initialized prior to registering
the rtc device.

CC: Wolfram Sang <w.sang@pengutronix.de>
CC: Alessandro Zummo <a.zummo@towertech.it>
CC: Thomas Gleixner <tglx@linutronix.de>
CC: rtc-linux@googlegroups.com
Signed-off-by: NJohn Stultz <john.stultz@linaro.org>