Due to distribution constraints it may not be possible to statically
compile the required RTC driver into the kernel.
Expand RTC_HCTOSYS support to cover all RTC devices (statically compiled
or not) by checking at the end of RTC device registration whether the
time should be synced.
Signed-off-by: Steve Muckle <smuckle@google.com>
Link: https://lore.kernel.org/r/20191106194625.116692-1-smuckle@google.com
Signed-off-by: Alexandre Belloni <alexandre.belloni@bootlin.com>
Use SPDX-License-Identifier instead of a verbose license text. Also fix the
block comment alignment.
Signed-off-by: Alexandre Belloni <alexandre.belloni@bootlin.com>
Implement devm_rtc_device_register using devm_rtc_allocate_device and
__rtc_register_device so there is only one path left to register rtc
devices.
Also mark it as deprecated so new drivers will hopefully use
devm_rtc_allocate_device and rtc_register_device that are less race prone
and allow avoiding the 2038, 2070, 2100 and 2106 bugs properly.
Signed-off-by: Alexandre Belloni <alexandre.belloni@bootlin.com>
All the remaining users of rtc_timers are passing the rtc_device as private
data. Enforce that and rename private_data to rtc.
Suggested-by: Arnd Bergmann <arnd@arndb.de>
Signed-off-by: Alexandre Belloni <alexandre.belloni@bootlin.com>
devm_rtc_device_unregister is not used by any driver and should not be used
by any new driver.
Signed-off-by: Alexandre Belloni <alexandre.belloni@bootlin.com>
Ensure the non managed version of the un/registration functions is not used
anymore. No driver is using it anymore and they should not be necessary.
Signed-off-by: Alexandre Belloni <alexandre.belloni@bootlin.com>
getnstimeofday64() is just a wrapper around the ktime accessor, so
we should use that directly.
I considered using ktime_get_boottime_ts64() (to avoid leap second
problems) or ktime_get_real_seconds() (to simplify the calculation,
but in the end concluded that the existing interface is probably
the most appropriate in this case.
Signed-off-by: Arnd Bergmann <arnd@arndb.de>
Signed-off-by: Alexandre Belloni <alexandre.belloni@bootlin.com>
From our investigation for all RTC drivers, 1 driver will be expired before
year 2017, 7 drivers will be expired before year 2038, 23 drivers will be
expired before year 2069, 72 drivers will be expired before 2100 and 104
drivers will be expired before 2106. Especially for these early expired
drivers, we need to expand the RTC range to make the RTC can still work
after the expired year.
So we can expand the RTC range by adding one offset to the time when reading
from hardware, and subtracting it when writing back. For example, if you have
an RTC that can do 100 years, and currently is configured to be based in
Jan 1 1970, so it can represents times from 1970 to 2069. Then if you change
the start year from 1970 to 2000, which means it can represents times from
2000 to 2099. By adding or subtracting the offset produced by moving the wrap
point, all times between 1970 and 1999 from RTC hardware could get interpreted
as times from 2070 to 2099, but the interpretation of dates between 2000 and
2069 would not change.
Signed-off-by: Baolin Wang <baolin.wang@linaro.org>
Signed-off-by: Alexandre Belloni <alexandre.belloni@bootlin.com>
Because nvmem_config is only used and copied at nvmem registration, remove
it from struct rtc_device.
All the rtc drivers using nvmem are now calling rtc_nvmem_register
directly.
Signed-off-by: Alexandre Belloni <alexandre.belloni@bootlin.com>
Switch the parent of the nvmem device to the parent of the rtc device so it
can be registered before the RTC.
This is a small change in the ABI as the nvmem moves out of the
/sys/class/rtc/rtcX folder to be under the parent device folder (that is
where the previous nvram files where registered).
However, it is still available under its correct location,
/sys/bus/nvmem/devices which is the one that should be used by userspace
applications.
The other benefit is that the nvmem device can stay registered even if the
rtc registration fails. Or it is possible to not register the rtc if the
nvmem registration failed.
Finally, it makes a lot of sense for devices that actually have different
i2c or spi addresses for the RTC and the EEPROM. That is basically how it
would end up when using MFD or even completely separate devices.
Signed-off-by: Alexandre Belloni <alexandre.belloni@bootlin.com>
To be able to remove nvmem_config from struct rtc_device, pass it as a
parameter to rtc_nvmem_register.
Signed-off-by: Alexandre Belloni <alexandre.belloni@bootlin.com>
ntp is currently hardwired to try and call the rtc set when wall clock
tv_nsec is 0.5 seconds. This historical behaviour works well with certain
PC RTCs, but is not universal to all rtc hardware.
Change how this works by introducing the driver specific concept of
set_offset_nsec, the delay between current wall clock time and the target
time to set (with a 0 tv_nsecs).
For x86-style CMOS set_offset_nsec should be -0.5 s which causes the last
second to be written 0.5 s after it has started.
For compat with the old rtc_set_ntp_time, the value is defaulted to
+ 0.5 s, which causes the next second to be written 0.5s before it starts,
as things were before this patch.
Testing shows many non-x86 RTCs would like set_offset_nsec ~= 0,
so ultimately each RTC driver should set the set_offset_nsec according
to its needs, and non x86 architectures should stop using
update_persistent_clock64 in order to access this feature.
Future patches will revise the drivers as needed.
Since CMOS and RTC now have very different handling they are split
into two dedicated code paths, sharing the support code, and ifdefs
are replaced with IS_ENABLED.
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Ingo Molnar <mingo@kernel.org>
Cc: Miroslav Lichvar <mlichvar@redhat.com>
Cc: Richard Cochran <richardcochran@gmail.com>
Cc: Prarit Bhargava <prarit@redhat.com>
Cc: Stephen Boyd <stephen.boyd@linaro.org>
Signed-off-by: Jason Gunthorpe <jgunthorpe@obsidianresearch.com>
Signed-off-by: John Stultz <john.stultz@linaro.org>
Many RTCs have an on board non volatile storage. It can be battery backed
RAM or an EEPROM. Use the nvmem subsystem to export it to both userspace
and in-kernel consumers.
This stays compatible with the previous (non documented) ABI that was using
/sys/class/rtc/rtcx/device/nvram to export that memory. But will warn about
the deprecation.
Signed-off-by: Alexandre Belloni <alexandre.belloni@free-electrons.com>
Introduce rtc_register_device() to register an already allocated and
initialized struct rtc_device. It automatically sets up the owner and the
two steps allocation/registration will allow to remove race conditions in
the IRQ handling of some driver. It also allows to properly extend the core
without adding more arguments to rtc_device_register().
Signed-off-by: Alexandre Belloni <alexandre.belloni@free-electrons.com>
Create rtc_allocate_device to allocate memory for a struct rtc_device and
initialize it.
Signed-off-by: Alexandre Belloni <alexandre.belloni@free-electrons.com>
rtc->name is only used in messages were it is superfluous. Remove it
completely from the structure.
Signed-off-by: Alexandre Belloni <alexandre.belloni@free-electrons.com>
Mostly straightforward, but we had to remove the rtc_dev_add/del_device
functions as they split up the cdev_add and the device_add.
Doing this also revealed that there was likely another subtle bug:
seeing cdev_add was done after device_register, the cdev probably
was not ready before device_add when the uevent occurs. This would
race with userspace, if it tried to use the device directly after
the uevent. This is fixed just by using the new helper function.
Another weird thing is this driver would, in some error cases, call
cdev_add() without calling cdev_init. This patchset corrects this
by avoiding calling cdev_add if the devt is not set.
Signed-off-by: Logan Gunthorpe <logang@deltatee.com>
Acked-by: Alexandre Belloni <alexandre.belloni@free-electrons.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
The Makefile/Kconfig currently controlling compilation of this code is:
obj-$(CONFIG_RTC_CLASS) += rtc-core.o
rtc-core-y := class.o interface.o
drivers/rtc/Kconfig:menuconfig RTC_CLASS
drivers/rtc/Kconfig: bool "Real Time Clock"
...meaning that it currently is not being built as a module by anyone.
Lets remove the modular code that is essentially orphaned, so that
when reading the code there is no doubt it is builtin-only.
We don't replace module.h with init.h since the file does need
to know what a struct module is.
We also delete the MODULE_LICENSE tag etc. since all that information
is already contained at the top of the file in the comments.
Signed-off-by: Paul Gortmaker <paul.gortmaker@windriver.com>
Signed-off-by: Alexandre Belloni <alexandre.belloni@free-electrons.com>
Instead of creating wakealarm attribute manually, after the device has been
registered, let's rely on facilities provided by the attribute groups to
control which attributes are visible and which are not. This allows to
create all needed attributes at once, at the same time that we register RTC
class device.
Signed-off-by: Dmitry Torokhov <dmitry.torokhov@gmail.com>
Reviewed-by: Krzysztof Kozlowski <k.kozlowski@samsung.com>
Signed-off-by: Alexandre Belloni <alexandre.belloni@free-electrons.com>
