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path: root/drivers/rtc
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2021-01-26rtc: pcf2127: Disable Power-On Reset OverridePhilipp Rosenberger
To resume normal operation after a total power loss (no or empty battery) the "Power-On Reset Override (PORO)" facility needs to be disabled. The register reset value sets the PORO enabled and the data sheet recommends setting it to disabled for normal operation. From what I've seen on the PCF2127 and PCF2129 there is no event generated at the interrupt pin (INT), as long the PORO bit is set. This behavior is not documented in the manual. Signed-off-by: Philipp Rosenberger <p.rosenberger@kunbus.com> Signed-off-by: Alexandre Belloni <alexandre.belloni@bootlin.com> Link: https://lore.kernel.org/r/20210118085752.5759-2-p.rosenberger@kunbus.com
2021-01-25rtc: tps65910: Support wakeup-source propertyDmitry Osipenko
TPS65910 is a PMIC MFD device and RTC is one of its functions. The wakeup-source DT property is specified for the parent MFD device and we need to use this property for the RTC in order to allow to use RTC alarm for waking up system from suspend by default, instead of requiring user to enable wakeup manually via sysfs. Tested-by: Peter Geis <pgwipeout@gmail.com> Tested-by: Matt Merhar <mattmerhar@protonmail.com> Signed-off-by: Dmitry Osipenko <digetx@gmail.com> Signed-off-by: Alexandre Belloni <alexandre.belloni@bootlin.com> Link: https://lore.kernel.org/r/20210120211603.18555-1-digetx@gmail.com
2021-01-25rtc: stm32: use rtc_lock/rtc_unlockAlexandre Belloni
Avoid accessing directly rtc->ops_lock and use the RTC core helpers. Signed-off-by: Alexandre Belloni <alexandre.belloni@bootlin.com> Link: https://lore.kernel.org/r/20210119220653.677750-14-alexandre.belloni@bootlin.com
2021-01-25rtc: rx8025: use rtc_lock/rtc_unlockAlexandre Belloni
Avoid accessing directly rtc->ops_lock and use the RTC core helpers. Signed-off-by: Alexandre Belloni <alexandre.belloni@bootlin.com> Link: https://lore.kernel.org/r/20210119220653.677750-13-alexandre.belloni@bootlin.com
2021-01-25rtc: rx8010: use rtc_lock/rtc_unlockAlexandre Belloni
Avoid accessing directly rtc->ops_lock and use the RTC core helpers. Signed-off-by: Alexandre Belloni <alexandre.belloni@bootlin.com> Link: https://lore.kernel.org/r/20210119220653.677750-12-alexandre.belloni@bootlin.com
2021-01-25rtc: rv3029: use rtc_lock/rtc_unlockAlexandre Belloni
Avoid accessing directly rtc->ops_lock and use the RTC core helpers. Signed-off-by: Alexandre Belloni <alexandre.belloni@bootlin.com> Link: https://lore.kernel.org/r/20210119220653.677750-11-alexandre.belloni@bootlin.com
2021-01-25rtc: pcf2123: use rtc_lock/rtc_unlockAlexandre Belloni
Avoid accessing directly rtc->ops_lock and use the RTC core helpers. Signed-off-by: Alexandre Belloni <alexandre.belloni@bootlin.com> Link: https://lore.kernel.org/r/20210119220653.677750-10-alexandre.belloni@bootlin.com
2021-01-25rtc: mcp795: use rtc_lock/rtc_unlockAlexandre Belloni
Avoid accessing directly rtc->ops_lock and use the RTC core helpers. Signed-off-by: Alexandre Belloni <alexandre.belloni@bootlin.com> Link: https://lore.kernel.org/r/20210119220653.677750-9-alexandre.belloni@bootlin.com
2021-01-25rtc: m41t80: use rtc_lock/rtc_unlockAlexandre Belloni
Avoid accessing directly rtc->ops_lock and use the RTC core helpers. Signed-off-by: Alexandre Belloni <alexandre.belloni@bootlin.com> Link: https://lore.kernel.org/r/20210119220653.677750-8-alexandre.belloni@bootlin.com
2021-01-25rtc: hym8563: use rtc_lock/rtc_unlockAlexandre Belloni
Avoid accessing directly rtc->ops_lock and use the RTC core helpers. Signed-off-by: Alexandre Belloni <alexandre.belloni@bootlin.com> Link: https://lore.kernel.org/r/20210119220653.677750-7-alexandre.belloni@bootlin.com
2021-01-25rtc: ds3232: use rtc_lock/rtc_unlockAlexandre Belloni
Avoid accessing directly rtc->ops_lock and use the RTC core helpers. Signed-off-by: Alexandre Belloni <alexandre.belloni@bootlin.com> Link: https://lore.kernel.org/r/20210119220653.677750-6-alexandre.belloni@bootlin.com
2021-01-25rtc: ds1685: use rtc_lock/rtc_unlockAlexandre Belloni
Avoid accessing directly rtc->ops_lock and use the RTC core helpers. Signed-off-by: Alexandre Belloni <alexandre.belloni@bootlin.com> Acked-by: Joshua Kinard <kumba@gentoo.org> Link: https://lore.kernel.org/r/20210119220653.677750-5-alexandre.belloni@bootlin.com
2021-01-25rtc: ds1307: use rtc_lock/rtc_unlockAlexandre Belloni
Avoid accessing directly rtc->ops_lock and use the RTC core helpers. Signed-off-by: Alexandre Belloni <alexandre.belloni@bootlin.com> Link: https://lore.kernel.org/r/20210119220653.677750-4-alexandre.belloni@bootlin.com
2021-01-25rtc: ds1305: use rtc_lock/rtc_unlockAlexandre Belloni
Avoid accessing directly rtc->ops_lock and use the RTC core helpers. Signed-off-by: Alexandre Belloni <alexandre.belloni@bootlin.com> Link: https://lore.kernel.org/r/20210119220653.677750-3-alexandre.belloni@bootlin.com
2021-01-25rtc: asm9260: use rtc_lock/rtc_unlockAlexandre Belloni
Avoid accessing directly rtc->ops_lock and use the RTC core helpers. Signed-off-by: Alexandre Belloni <alexandre.belloni@bootlin.com> Link: https://lore.kernel.org/r/20210119220653.677750-2-alexandre.belloni@bootlin.com
2021-01-25rtc: ac100: use rtc_lock/rtc_unlockAlexandre Belloni
Avoid accessing directly rtc->ops_lock and use the RTC core helpers. Signed-off-by: Alexandre Belloni <alexandre.belloni@bootlin.com> Link: https://lore.kernel.org/r/20210125221402.1958484-1-alexandre.belloni@bootlin.com
2021-01-25rtc: mrst: Remove driver for deprecated platformAndy Shevchenko
Intel Moorestown and Medfield are quite old Intel Atom based 32-bit platforms, which were in limited use in some Android phones, tablets and consumer electronics more than eight years ago. There are no bugs or problems ever reported outside from Intel for breaking any of that platforms for years. It seems no real users exists who run more or less fresh kernel on it. The commit 05f4434bc130 ("ASoC: Intel: remove mfld_machine") also in align with this theory. Due to above and to reduce a burden of supporting outdated drivers we remove the support of outdated platforms completely. Signed-off-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com> Acked-by: Alexandre Belloni <alexandre.belloni@bootlin.com> Acked-by: Linus Walleij <linus.walleij@linaro.org>
2021-01-23rtc: remove ste ab3100 driverArnd Bergmann
The ST-Ericsson U300 platform is getting removed, so this driver is no longer needed. Cc: Linus Walleij <linus.walleij@linaro.org> Signed-off-by: Arnd Bergmann <arnd@arndb.de> Reviewed-by: Linus Walleij <linus.walleij@linaro.org> Signed-off-by: Alexandre Belloni <alexandre.belloni@bootlin.com> Link: https://lore.kernel.org/r/20210120154158.1860736-4-arnd@kernel.org
2021-01-23rtc: remove ste coh901 driverArnd Bergmann
The ST-Ericsson U300 platform is getting removed, so this driver is no longer needed. Cc: Linus Walleij <linus.walleij@linaro.org> Signed-off-by: Arnd Bergmann <arnd@arndb.de> Reviewed-by: Linus Walleij <linus.walleij@linaro.org> Signed-off-by: Alexandre Belloni <alexandre.belloni@bootlin.com> Link: https://lore.kernel.org/r/20210120154158.1860736-3-arnd@kernel.org
2021-01-23rtc: remove sirfsoc driverArnd Bergmann
The CSR SiRF prima2/atlas platforms are getting removed, so this driver is no longer needed. Cc: Barry Song <baohua@kernel.org> Signed-off-by: Arnd Bergmann <arnd@arndb.de> Acked-by: Barry Song <baohua@kernel.org> Signed-off-by: Alexandre Belloni <alexandre.belloni@bootlin.com> Link: https://lore.kernel.org/r/20210120154158.1860736-2-arnd@kernel.org
2021-01-16rtc: tps65910: remove tps65910_rtc_ops_noirqAlexandre Belloni
Clear RTC_FEATURE_ALARM to signal that alarms are not available instead of having a supplementary struct rtc_class_ops without alarm callbacks. Signed-off-by: Alexandre Belloni <alexandre.belloni@bootlin.com> Link: https://lore.kernel.org/r/20210110231752.1418816-18-alexandre.belloni@bootlin.com
2021-01-16rtc: rv8803: constify rv8803_rtc_opsAlexandre Belloni
Use RTC_FEATURE_ALARM to signal to the core whether alarms are available instead of changing the global struct rtc_class_ops, allowing to make it const. Signed-off-by: Alexandre Belloni <alexandre.belloni@bootlin.com> Link: https://lore.kernel.org/r/20210110231752.1418816-17-alexandre.belloni@bootlin.com
2021-01-16rtc: rv3032: constify rv3032_rtc_opsAlexandre Belloni
Use RTC_FEATURE_ALARM to signal to the core whether alarms are available instead of changing the global struct rtc_class_ops, allowing to make it const. Signed-off-by: Alexandre Belloni <alexandre.belloni@bootlin.com> Link: https://lore.kernel.org/r/20210110231752.1418816-16-alexandre.belloni@bootlin.com
2021-01-16rtc: rv3029: constify rv3029_rtc_opsAlexandre Belloni
Use RTC_FEATURE_ALARM to signal to the core whether alarms are available instead of changing the global struct rtc_class_ops, allowing to make it const. Signed-off-by: Alexandre Belloni <alexandre.belloni@bootlin.com> Link: https://lore.kernel.org/r/20210110231752.1418816-15-alexandre.belloni@bootlin.com
2021-01-16rtc: rv3028: constify rv3028_rtc_opsAlexandre Belloni
Use RTC_FEATURE_ALARM to signal to the core whether alarms are available instead of changing the global struct rtc_class_ops, allowing to make it const. Signed-off-by: Alexandre Belloni <alexandre.belloni@bootlin.com> Link: https://lore.kernel.org/r/20210110231752.1418816-14-alexandre.belloni@bootlin.com
2021-01-16rtc: opal: constify opal_rtc_opsAlexandre Belloni
Use RTC_FEATURE_ALARM to signal to the core whether alarms are available instead of changing the global struct rtc_class_ops, allowing to make it const. Signed-off-by: Alexandre Belloni <alexandre.belloni@bootlin.com> Link: https://lore.kernel.org/r/20210110231752.1418816-13-alexandre.belloni@bootlin.com
2021-01-16rtc: m41t80: constify m41t80_rtc_opsAlexandre Belloni
Use RTC_FEATURE_ALARM to signal to the core whether alarms are available instead of changing the global struct rtc_class_ops, allowing to make it const. Signed-off-by: Alexandre Belloni <alexandre.belloni@bootlin.com> Link: https://lore.kernel.org/r/20210110231752.1418816-12-alexandre.belloni@bootlin.com
2021-01-16rtc: pcf85363: drop a struct rtc_class_opsAlexandre Belloni
Merge both struct rtc_class_ops in a single one and use RTC_FEATURE_ALARM to signal to the core whether alarms are available. Signed-off-by: Alexandre Belloni <alexandre.belloni@bootlin.com> Link: https://lore.kernel.org/r/20210110231752.1418816-11-alexandre.belloni@bootlin.com
2021-01-16rtc: rx8010: drop a struct rtc_class_opsAlexandre Belloni
Merge both struct rtc_class_ops in a single one and use RTC_FEATURE_ALARM to signal to the core whether alarms are available. Signed-off-by: Alexandre Belloni <alexandre.belloni@bootlin.com> Link: https://lore.kernel.org/r/20210110231752.1418816-10-alexandre.belloni@bootlin.com
2021-01-16rtc: pcf85063: remove pcf85063_rtc_ops_alarmAlexandre Belloni
Move the alarm callbacks in pcf85063_rtc_ops and use RTC_FEATURE_ALARM to signal to the core whether alarms are available instead of having a supplementary struct rtc_class_ops without alarm callbacks. Signed-off-by: Alexandre Belloni <alexandre.belloni@bootlin.com> Link: https://lore.kernel.org/r/20210110231752.1418816-9-alexandre.belloni@bootlin.com
2021-01-16rtc: pcf2127: remove pcf2127_rtc_alrm_opsAlexandre Belloni
Move the alarm callbacks in pcf2127_rtc_ops and use RTC_FEATURE_ALARM to signal to the core whether alarms are available instead of having a supplementary struct rtc_class_ops without alarm callbacks. Signed-off-by: Alexandre Belloni <alexandre.belloni@bootlin.com> Link: https://lore.kernel.org/r/20210110231752.1418816-8-alexandre.belloni@bootlin.com
2021-01-16rtc: m48t59: remove m48t02_rtc_opsAlexandre Belloni
Clear RTC_FEATURE_ALARM to signal that alarms are not available instead of having a supplementary struct rtc_class_ops without alarm callbacks. Signed-off-by: Alexandre Belloni <alexandre.belloni@bootlin.com> Link: https://lore.kernel.org/r/20210110231752.1418816-7-alexandre.belloni@bootlin.com
2021-01-16rtc: mv: remove mv_rtc_alarm_opsAlexandre Belloni
Move the alarm callbacks in mv_rtc_ops and clear RTC_FEATURE_ALARM to signal that alarms are not available instead of having a supplementary struct rtc_class_ops. Signed-off-by: Alexandre Belloni <alexandre.belloni@bootlin.com> Link: https://lore.kernel.org/r/20210110231752.1418816-6-alexandre.belloni@bootlin.com
2021-01-16rtc: cmos: remove cmos_rtc_ops_no_alarmAlexandre Belloni
Clear RTC_FEATURE_ALARM to signal that alarms are not available instead of having a supplementary struct rtc_class_ops with a NULL .set_alarm. Signed-off-by: Alexandre Belloni <alexandre.belloni@bootlin.com> Link: https://lore.kernel.org/r/20210110231752.1418816-5-alexandre.belloni@bootlin.com
2021-01-16rtc: armada38x: remove armada38x_rtc_ops_noirqAlexandre Belloni
Clear RTC_FEATURE_ALARM to signal that alarms are not available instead of having a supplementary struct rtc_class_ops with a NULL .set_alarm. Signed-off-by: Alexandre Belloni <alexandre.belloni@bootlin.com> Link: https://lore.kernel.org/r/20210110231752.1418816-4-alexandre.belloni@bootlin.com
2021-01-16rtc: pl031: use RTC_FEATURE_ALARMAlexandre Belloni
Clear RTC_FEATURE_ALARM instead of setting set_alarm, read_alarm and alarm_irq_enable to NULL. Signed-off-by: Alexandre Belloni <alexandre.belloni@bootlin.com> Acked-by: Linus Walleij <linus.walleij@linaro.org> Link: https://lore.kernel.org/r/20210110231752.1418816-3-alexandre.belloni@bootlin.com
2021-01-16rtc: introduce features bitfieldAlexandre Belloni
Introduce a bitfield to allow the drivers to announce the available features for an RTC. The main use case would be to better handle alarms, that could be present or not or have a minute resolution or may need a correct week day to be set. Use the newly introduced RTC_FEATURE_ALARM bit to then test whether alarms are available instead of relying on the presence of ops->set_alarm. Signed-off-by: Alexandre Belloni <alexandre.belloni@bootlin.com> Link: https://lore.kernel.org/r/20210110231752.1418816-2-alexandre.belloni@bootlin.com
2021-01-16rtc: s5m: check the return value of s5m8767_rtc_init_reg()Bartosz Golaszewski
This function can fail if regmap operations fail so check its return value in probe(). Signed-off-by: Bartosz Golaszewski <bgolaszewski@baylibre.com> Reviewed-by: Krzysztof Kozlowski <krzk@kernel.org> Signed-off-by: Alexandre Belloni <alexandre.belloni@bootlin.com> Link: https://lore.kernel.org/r/20210114102219.23682-4-brgl@bgdev.pl
2021-01-16rtc: s5m: use devm_i2c_new_dummy_device()Bartosz Golaszewski
Use the managed variant of i2c_new_dummy_device() to shrink code and remove the goto label. We can drop the remove callback now too. Signed-off-by: Bartosz Golaszewski <bgolaszewski@baylibre.com> Reviewed-by: Krzysztof Kozlowski <krzk@kernel.org> Signed-off-by: Alexandre Belloni <alexandre.belloni@bootlin.com> Link: https://lore.kernel.org/r/20210114102219.23682-3-brgl@bgdev.pl
2021-01-16rtc: s5m: select REGMAP_I2CBartosz Golaszewski
The rtc-s5m uses the I2C regmap but doesn't select it in Kconfig so depending on the configuration the build may fail. Fix it. Fixes: 959df7778bbd ("rtc: Enable compile testing for Maxim and Samsung drivers") Signed-off-by: Bartosz Golaszewski <bgolaszewski@baylibre.com> Reviewed-by: Krzysztof Kozlowski <krzk@kernel.org> Signed-off-by: Alexandre Belloni <alexandre.belloni@bootlin.com> Link: https://lore.kernel.org/r/20210114102219.23682-2-brgl@bgdev.pl
2021-01-13rtc: opal: set rangeAlexandre Belloni
It is a BCD RTC with 4 digits for the year. Signed-off-by: Alexandre Belloni <alexandre.belloni@bootlin.com> Link: https://lore.kernel.org/r/20210110224606.1414307-1-alexandre.belloni@bootlin.com
2021-01-13rtc: tx4939: Remove driverThomas Bogendoerfer
CPU support for TX49xx is getting removed, so remove rtc driver for it. Signed-off-by: Thomas Bogendoerfer <tsbogend@alpha.franken.de> Signed-off-by: Alexandre Belloni <alexandre.belloni@bootlin.com> Link: https://lore.kernel.org/r/20210105140305.141401-9-tsbogend@alpha.franken.de
2021-01-12rtc: rx6110: fix build against modular I2CArnd Bergmann
With CONFIG_I2C=m, the #ifdef section is disabled, as shown by this warning: drivers/rtc/rtc-rx6110.c:314:12: error: unused function 'rx6110_probe' [-Werror,-Wunused-function] Change the driver to use IS_ENABLED() instead, which works for both module and built-in subsystems. Fixes: afa819c2c6bf ("rtc: rx6110: add i2c support") Signed-off-by: Arnd Bergmann <arnd@arndb.de> Signed-off-by: Alexandre Belloni <alexandre.belloni@bootlin.com> Link: https://lore.kernel.org/r/20201230145938.3254459-1-arnd@kernel.org
2021-01-12rtc: pm8xxx: Read ALARM_EN and update to alarm enabled statusGuixiong Wei
ALARM_EN status is retained in PMIC register after device shutdown if poweron_alarm is enabled. Read it to make sure the driver has consistent value with the register status. Signed-off-by: Guixiong Wei <guixiong@codeaurora.org> Signed-off-by: Alexandre Belloni <alexandre.belloni@bootlin.com> Link: https://lore.kernel.org/r/1608809337-18852-1-git-send-email-guixiong@codeaurora.org
2020-12-20Merge tag 'rtc-5.11' of ↵Linus Torvalds
git://git.kernel.org/pub/scm/linux/kernel/git/abelloni/linux Pull RTC updates from Alexandre Belloni: "Subsystem: - Remove nvram ABI. There was no complaints about the deprecation for the last 3 years. - Improve RTC device allocation and registration - Now available for ARCH=um Drivers: - at91rm9200: correction and sam9x60 support - ds1307: improve ACPI support - mxc: now DT only - pcf2127: watchdog support now needs the reset-source property - pcf8523: set range - rx6110: i2c support" * tag 'rtc-5.11' of git://git.kernel.org/pub/scm/linux/kernel/git/abelloni/linux: (43 commits) rtc: pcf2127: only use watchdog when explicitly available dt-bindings: rtc: add reset-source property rtc: fix RTC removal rtc: s3c: Remove dead code related to periodic tick handling rtc: s3c: Disable all enable (RTC, tick) bits in the probe rtc: ep93xx: Fix NULL pointer dereference in ep93xx_rtc_read_time rtc: test: remove debug message rtc: mxc{,_v2}: enable COMPILE_TEST rtc: enable RTC framework on ARCH=um rtc: pcf8523: use BIT rtc: pcf8523: set range rtc: pcf8523: switch to devm_rtc_allocate_device rtc: destroy mutex when releasing the device rtc: shrink devm_rtc_allocate_device() rtc: rework rtc_register_device() resource management rtc: nvmem: emit an error message when nvmem registration fails rtc: add devm_ prefix to rtc_nvmem_register() rtc: nvmem: remove nvram ABI Documentation: list RTC devres helpers in devres.rst rtc: omap: use devm_pinctrl_register() ...
2020-12-19rtc: pcf2127: only use watchdog when explicitly availableUwe Kleine-König
Most boards using the pcf2127 chip (in my bubble) don't make use of the watchdog functionality and the respective output is not connected. The effect on such a board is that there is a watchdog device provided that doesn't work. So only register the watchdog if the device tree has a "reset-source" property. Signed-off-by: Uwe Kleine-König <u.kleine-koenig@pengutronix.de> [RV: s/has-watchdog/reset-source/] Signed-off-by: Rasmus Villemoes <rasmus.villemoes@prevas.dk> Signed-off-by: Alexandre Belloni <alexandre.belloni@bootlin.com> Link: https://lore.kernel.org/r/20201218101054.25416-3-rasmus.villemoes@prevas.dk
2020-12-16rtc: fix RTC removalAlexandre Belloni
Since the rtc_register_device, removing an RTC device will end with a refcount_t: underflow; use-after-free warning since put_device is called twice in the device tear down path. Fixes: fdcfd854333b ("rtc: rework rtc_register_device() resource management") Signed-off-by: Alexandre Belloni <alexandre.belloni@bootlin.com> Reviewed-by: Bartosz Golaszewski <bgolaszewski@baylibre.com> Link: https://lore.kernel.org/r/20201205231449.610980-1-alexandre.belloni@bootlin.com
2020-12-11ntp: Make the RTC sync offset less obscureThomas Gleixner
The current RTC set_offset_nsec value is not really intuitive to understand. tsched twrite(t2.tv_sec - 1) t2 (seconds increment) The offset is calculated from twrite based on the assumption that t2 - twrite == 1s. That means for the MC146818 RTC the offset needs to be negative so that the write happens 500ms before t2. It's easier to understand when the whole calculation is based on t2. That avoids negative offsets and the meaning is obvious: t2 - twrite: The time defined by the chip when seconds increment after the write. twrite - tsched: The time for the transport to the point where the chip is updated. ==> set_offset_nsec = t2 - tsched ttransport = twrite - tsched tRTCinc = t2 - twrite ==> set_offset_nsec = ttransport + tRTCinc tRTCinc is a chip property and can be obtained from the data sheet. ttransport depends on how the RTC is connected. It is close to 0 for directly accessible RTCs. For RTCs behind a slow bus, e.g. i2c, it's the time required to send the update over the bus. This can be estimated or even calibrated, but that's a different problem. Adjust the implementation and update comments accordingly. Signed-off-by: Thomas Gleixner <tglx@linutronix.de> Acked-by: Alexandre Belloni <alexandre.belloni@bootlin.com> Link: https://lore.kernel.org/r/20201206220542.263204937@linutronix.de
2020-12-11ntp, rtc: Move rtc_set_ntp_time() to ntp codeThomas Gleixner
rtc_set_ntp_time() is not really RTC functionality as the code is just a user of RTC. Move it into the NTP code which allows further cleanups. Requested-by: Alexandre Belloni <alexandre.belloni@bootlin.com> Signed-off-by: Thomas Gleixner <tglx@linutronix.de> Reviewed-by: Jason Gunthorpe <jgg@nvidia.com> Acked-by: Alexandre Belloni <alexandre.belloni@bootlin.com> Link: https://lore.kernel.org/r/20201206220542.166871172@linutronix.de
2020-12-11rtc: core: Make the sync offset default more realisticThomas Gleixner
The offset which is used to steer the start of an RTC synchronization update via rtc_set_ntp_time() is huge. The math behind this is: tsched twrite(t2.tv_sec - 1) t2 (seconds increment) twrite - tsched is the transport time for the write to hit the device. t2 - twrite depends on the chip and is for most chips one second. The rtc_set_ntp_time() calculation of tsched is: tsched = t2 - 1sec - (t2 - twrite) The default for the sync offset is 500ms which means that twrite - tsched is 500ms assumed that t2 - twrite is one second. This is 0.5 seconds off for RTCs which are directly accessible by IO writes and probably for the majority of i2C/SPI based RTC off by an order of magnitude. Set it to 5ms which should bring it closer to reality. The default can be adjusted by drivers (rtc_cmos does so) and could be adjusted further by a calibration method which is an orthogonal problem. Signed-off-by: Thomas Gleixner <tglx@linutronix.de> Reviewed-by: Jason Gunthorpe <jgg@nvidia.com> Acked-by: Alexandre Belloni <alexandre.belloni@bootlin.com> Link: https://lore.kernel.org/r/20201206220541.960333166@linutronix.de
generated by cgit (git 2.34.1) at 2025-07-19 23:51:57 +0000