Pull RTC updates from Alexandre Belloni:
"This includes new ioctls to get and set parameters and in particular
the backup switch mode that is needed for some RTCs to actually enable
the backup voltage (and have a useful RTC).
The same interface can also be used to get the actual features
supported by the RTC so userspace has a better way than trying and
failing.
Summary:
Subsystem:
- Add new ioctl to get and set extra RTC parameters, this includes
backup switch mode
- Expose available features to userspace, in particular, when alarmas
have a resolution of one minute instead of a second.
- Let the core handle those alarms with a minute resolution
New driver:
- MSTAR MSC313 RTC
Drivers:
- Add SPI ID table where necessary
- Add BSM support for rv3028, rv3032 and pcf8523
- s3c: set RTC range
- rx8025: set range, implement .set_offset and .read_offset"
* tag 'rtc-5.16' of git://git.kernel.org/pub/scm/linux/kernel/git/abelloni/linux: (50 commits)
rtc: rx8025: use .set_offset/.read_offset
rtc: rx8025: use rtc_add_group
rtc: rx8025: clear RTC_FEATURE_ALARM when alarm are not supported
rtc: rx8025: set range
rtc: rx8025: let the core handle the alarm resolution
rtc: rx8025: switch to devm_rtc_allocate_device
rtc: ab8500: let the core handle the alarm resolution
rtc: ab-eoz9: support UIE when available
rtc: ab-eoz9: use RTC_FEATURE_UPDATE_INTERRUPT
rtc: rv3032: let the core handle the alarm resolution
rtc: s35390a: let the core handle the alarm resolution
rtc: handle alarms with a minute resolution
rtc: pcf85063: silence cppcheck warning
rtc: rv8803: fix writing back ctrl in flag register
rtc: s3c: Add time range
rtc: s3c: Extract read/write IO into separate functions
rtc: s3c: Remove usage of devm_rtc_device_register()
rtc: tps80031: Remove driver
rtc: sun6i: Allow probing without an early clock provider
rtc: pcf8523: add BSM support
...
Tell the RTC core UIE are not supported because the resolution of the alarm
is a minute.
Note that this is in fact also fixing how the resolution is reported as the
previous test was simply ensuring the alarm was more than a minute in the
future while the register has a minute resolution.
This would be ok if the alarm was a countdown but ab8500_rtc_read_alarm
suggests otherwise and the AB8500 datasheet states that the RTC
documentation is not public.
Finally, the comment is wrong and what makes the UIE emulation work is
uie_unsupported being set.
Signed-off-by: Alexandre Belloni <alexandre.belloni@bootlin.com>
Acked-by: Linus Walleij <linus.walleij@linaro.org>
Link: https://lore.kernel.org/r/20211107225458.111068-6-alexandre.belloni@bootlin.com
Handle alarms with a minute resolution in the core. Until now drivers have
been open coding the seconds part removal and have been doing that wrongly.
Most of them are rounding up which means the allow the system to miss
deadlines. So, round down and let __rtc_set_alarm return immediately if the
time has already passed.
Signed-off-by: Alexandre Belloni <alexandre.belloni@bootlin.com>
Link: https://lore.kernel.org/r/20211107225458.111068-1-alexandre.belloni@bootlin.com
Samsung SoC drivers changes for v5.16
1. Convert Exynos ChipID and ASV driver to a module and make it a
default, instead of selected. The driver is not essential, so it
could be disabled, if needed.
2. Add support for Exynos850 and Exynos Auto v9 to Exynos ChipID and ASV
driver.
3. Get rid of HAVE_S3C_RTC because it was adding just another layer
instead of direct dependencies.
4. Minor cleanups.
* tag 'samsung-drivers-5.16' of git://git.kernel.org/pub/scm/linux/kernel/git/krzk/linux:
soc: samsung: exynos-chipid: add exynosautov9 SoC support
rtc: s3c: remove HAVE_S3C_RTC in favor of direct dependencies
soc: samsung: exynos-chipid: Add Exynos850 support
dt-bindings: samsung: exynos-chipid: Document Exynos850 compatible
soc: samsung: exynos-chipid: Pass revision reg offsets
soc: samsung: pm_domains: drop unused is_off field
arm64: exynos: don't have ARCH_EXYNOS select EXYNOS_CHIPID
soc: samsung: exynos-chipid: do not enforce built-in
soc: samsung: exynos-chipid: convert to a module
soc: samsung: exynos-chipid: avoid soc_device_to_device()
soc: samsung: exynos-pmu: Fix compilation when nothing selects CONFIG_MFD_CORE
Link: https://lore.kernel.org/r/20211026094709.75692-2-krzysztof.kozlowski@canonical.com
Signed-off-by: Arnd Bergmann <arnd@arndb.de>
This RTC driver starts counting from 2000 to avoid Y2K problem. Also it
only supports 100 years range for all RTCs. Provide that info to RTC
framework. Also remove check for 100 years range in s3c_rtc_settime(),
as RTC core won't pass any invalid values to the driver, now that
correct range is set.
Here is the rationale on 100 years range limitation. Info on different
Samsung RTCs (credit goes to Krzysztof Kozlowski):
- All S3C chips have only 8-bit wide year register (can store 100
years range in BCD format)
- S5Pv210 and Exynos chips have 12-bit year register (can store 1000
years range in BCD format)
But in reality we usually can't make use of those 12 bits either:
- RTCs might think that both 2000 and 2100 years are leap years. So
when the YEAR register is 0, RTC goes from 28 Feb to 29 Feb, and
when the YEAR register is 100, RTC also goes from 28 Feb to 29 Feb.
This is of course incorrect: RTC breaks leap year criteria, which
breaks the time contiguity, which leads to inability to use the RTC
after year of 2099. It was found for example on Exynos850 SoC.
- Despite having 12 bits for holding the year value, RTC might
overflow the year value internally much earlier. For example, on
Exynos850 the RTC overflows when YEAR=159, making the next YEAR=0.
This way RTC actually has range of 160 years, not 1000 as one may
think.
All that said, there is no sense in trying to increase the time range
for more than 100 years on RTCs that seem capable of that. It also
doesn't have too much practical value -- current hardware will be
probably obsolete by 2100.
Tested manually on Exynos850 RTC:
$ date -s "1999-12-31 23:59:50"
$ hwclock -w -f /dev/rtc0
$ date -s "2100-01-01 00:00:00"
$ hwclock -w -f /dev/rtc0
$ date -s "2000-01-01 00:00:00"
$ hwclock -w -f /dev/rtc0
$ hwclock -r -f /dev/rtc0
$ date -s "2099-12-31 23:59:50"
$ hwclock -w -f /dev/rtc0
$ hwclock -r -f /dev/rtc0
Signed-off-by: Sam Protsenko <semen.protsenko@linaro.org>
Reviewed-by: Krzysztof Kozlowski <krzysztof.kozlowski@canonical.com>
Signed-off-by: Alexandre Belloni <alexandre.belloni@bootlin.com>
Link: https://lore.kernel.org/r/20211021202256.28517-4-semen.protsenko@linaro.org
Some SoCs have an RTC supported by this RTC driver, but do not have an
early clock provider declared here. Currently, this prevents the RTC
driver from probing, because it expects a global struct to already be
allocated. Fix probing the driver by copying the missing pieces from the
clock provider setup function, replacing them with the devm variants.
Signed-off-by: Samuel Holland <samuel@sholland.org>
Signed-off-by: Alexandre Belloni <alexandre.belloni@bootlin.com>
Link: https://lore.kernel.org/r/20210928080335.36706-7-samuel@sholland.org
