When pcf8563_clkout_round_rate() is called with a requested rate higher
than the highest supported rate, it currently returns 0, which disables
the clock. According to the clk API, round_rate() should instead return
the highest supported rate. Update the function to return the maximum
supported rate in this case.
Fixes: a39a6405d5 ("rtc: pcf8563: add CLKOUT to common clock framework")
Signed-off-by: Brian Masney <bmasney@redhat.com>
Link: https://lore.kernel.org/r/20250710-rtc-clk-round-rate-v1-5-33140bb2278e@redhat.com
Signed-off-by: Alexandre Belloni <alexandre.belloni@bootlin.com>
When pcf85063_clkout_round_rate() is called with a requested rate higher
than the highest supported rate, it currently returns 0, which disables
the clock. According to the clk API, round_rate() should instead return
the highest supported rate. Update the function to return the maximum
supported rate in this case.
Fixes: 8c229ab604 ("rtc: pcf85063: Add pcf85063 clkout control to common clock framework")
Signed-off-by: Brian Masney <bmasney@redhat.com>
Link: https://lore.kernel.org/r/20250710-rtc-clk-round-rate-v1-4-33140bb2278e@redhat.com
Signed-off-by: Alexandre Belloni <alexandre.belloni@bootlin.com>
When nct3018y_clkout_round_rate() is called with a requested rate higher
than the highest supported rate, it currently returns 0, which disables
the clock. According to the clk API, round_rate() should instead return
the highest supported rate. Update the function to return the maximum
supported rate in this case.
Fixes: 5adbaed16c ("rtc: Add NCT3018Y real time clock driver")
Signed-off-by: Brian Masney <bmasney@redhat.com>
Link: https://lore.kernel.org/r/20250710-rtc-clk-round-rate-v1-3-33140bb2278e@redhat.com
Signed-off-by: Alexandre Belloni <alexandre.belloni@bootlin.com>
When hym8563_clkout_round_rate() is called with a requested rate higher
than the highest supported rate, it currently returns 0, which disables
the clock. According to the clk API, round_rate() should instead return
the highest supported rate. Update the function to return the maximum
supported rate in this case.
Fixes: dcaf038493 ("rtc: add hym8563 rtc-driver")
Signed-off-by: Brian Masney <bmasney@redhat.com>
Link: https://lore.kernel.org/r/20250710-rtc-clk-round-rate-v1-2-33140bb2278e@redhat.com
Signed-off-by: Alexandre Belloni <alexandre.belloni@bootlin.com>
When ds3231_clk_sqw_round_rate() is called with a requested rate higher
than the highest supported rate, it currently returns 0, which disables
the clock. According to the clk API, round_rate() should instead return
the highest supported rate. Update the function to return the maximum
supported rate in this case.
Fixes: 6c6ff145b3 ("rtc: ds1307: add clock provider support for DS3231")
Signed-off-by: Brian Masney <bmasney@redhat.com>
Link: https://lore.kernel.org/r/20250710-rtc-clk-round-rate-v1-1-33140bb2278e@redhat.com
Signed-off-by: Alexandre Belloni <alexandre.belloni@bootlin.com>
Recently (in commit 7df4cfef8b ("rtc: Make rtc_time64_to_tm() support
dates before 1970")) the function rtc_time64_to_tm() was repaired for
times before 1970. This introduced two if blocks. Cassio Neri pointed
out that to be not neccessary and suggested an adaption that allows to
drop the two branch points again.
This is implemented here.
Also adapt the reference to the theoretical paper to link to the final
published article instead of the preprint on Cassio's request.
Suggested-by: Cassio Neri <cassio.neri@gmail.com>
Signed-off-by: Uwe Kleine-König <u.kleine-koenig@baylibre.com>
Link: https://lore.kernel.org/r/20250613142405.253420-2-u.kleine-koenig@baylibre.com
Signed-off-by: Alexandre Belloni <alexandre.belloni@bootlin.com>
In using CONFIG_RTC_HCTOSYS, rtc_hctosys() will sync the RTC time to the
kernel time as long as rtc_read_time() succeeds. In some power loss
situations, our supercapacitor-backed DS1342 RTC comes up with either an
unpredictable future time or the default 01/01/00 from the datasheet.
The oscillator stop flag (OSF) is set in these scenarios due to the
power loss and can be used to determine the validity of the RTC data.
This change expands the oscillator stop flag (OSF) handling that has
already been implemented for some chips to the ds1341 chip (DS1341 and
DS1342 share a datasheet). This handling manages the validity of the RTC
data in .read_time and .set_time based on the OSF.
Signed-off-by: Meagan Lloyd <meaganlloyd@linux.microsoft.com>
Reviewed-by: Tyler Hicks <code@tyhicks.com>
Acked-by: Rodolfo Giometti <giometti@enneenne.com>
Link: https://lore.kernel.org/r/1749665656-30108-3-git-send-email-meaganlloyd@linux.microsoft.com
Signed-off-by: Alexandre Belloni <alexandre.belloni@bootlin.com>
In using CONFIG_RTC_HCTOSYS, rtc_hctosys() will sync the RTC time to the
kernel time as long as rtc_read_time() succeeds. In some power loss
situations, our supercapacitor-backed DS1342 RTC comes up with either an
unpredictable future time or the default 01/01/00 from the datasheet.
The oscillator stop flag (OSF) is set in these scenarios due to the
power loss and can be used to determine the validity of the RTC data.
Some chip types in the ds1307 driver already have OSF handling to
determine whether .read_time provides valid RTC data or returns -EINVAL.
This change removes the clear of the OSF in .probe as the OSF needs to
be preserved to expand the OSF handling to the ds1341 chip type (note
that DS1341 and DS1342 share a datasheet).
Signed-off-by: Meagan Lloyd <meaganlloyd@linux.microsoft.com>
Reviewed-by: Tyler Hicks <code@tyhicks.com>
Acked-by: Rodolfo Giometti <giometti@enneenne.com>
Link: https://lore.kernel.org/r/1749665656-30108-2-git-send-email-meaganlloyd@linux.microsoft.com
Signed-off-by: Alexandre Belloni <alexandre.belloni@bootlin.com>
While the RTC framework intends to only handle dates after 1970 for
consumers, time conversion must also work for earlier dates to cover
e.g. storing dates beyond an RTC's range_max. This is most relevant for
the rtc-mt6397 driver that has
range_min = RTC_TIMESTAMP_BEGIN_1900;
range_max = mktime64(2027, 12, 31, 23, 59, 59);
and so needs working support for timestamps in 1900 starting in less than
three years.
So shift the tested interval of timestamps to also cover years 1900 to
1970.
Signed-off-by: Uwe Kleine-König <u.kleine-koenig@baylibre.com>
Signed-off-by: Alexandre Mergnat <amergnat@baylibre.com>
Link: https://lore.kernel.org/r/20250428-enable-rtc-v4-5-2b2f7e3f9349@baylibre.com
Signed-off-by: Alexandre Belloni <alexandre.belloni@bootlin.com>
This is easier to handle because you can just consult date(1) to convert
between a seconds-since-1970 value and a date string:
$ date --utc -d @3661
Thu Jan 1 01:01:01 AM UTC 1970
$ date -d "Jan 1 12:00:00 AM UTC 1900" +%s
-2208988800
The intended side effect is that this prepares the test for dates before
1970. The division of a negative value by 86400 doesn't result in the
desired days-since-1970 value as e.g. secs=-82739 should map to days=-1.
Signed-off-by: Uwe Kleine-König <u.kleine-koenig@baylibre.com>
Signed-off-by: Alexandre Mergnat <amergnat@baylibre.com>
Link: https://lore.kernel.org/r/20250428-enable-rtc-v4-3-2b2f7e3f9349@baylibre.com
Signed-off-by: Alexandre Belloni <alexandre.belloni@bootlin.com>
The comparison
rtc->start_secs > rtc->range_max
has a signed left-hand side and an unsigned right-hand side.
So the comparison might become true for negative start_secs which is
interpreted as a (possibly very large) positive value.
As a negative value can never be bigger than an unsigned value
the correct representation of the (mathematical) comparison
rtc->start_secs > rtc->range_max
in C is:
rtc->start_secs >= 0 && rtc->start_secs > rtc->range_max
Use that to fix the offset calculation currently used in the
rtc-mt6397 driver.
Fixes: 989515647e ("rtc: Add one offset seconds to expand RTC range")
Signed-off-by: Alexandre Mergnat <amergnat@baylibre.com>
Reviewed-by: Uwe Kleine-König <u.kleine-koenig@baylibre.com>
Link: https://lore.kernel.org/r/20250428-enable-rtc-v4-2-2b2f7e3f9349@baylibre.com
Signed-off-by: Alexandre Belloni <alexandre.belloni@bootlin.com>
Conversion of dates before 1970 is still relevant today because these
dates are reused on some hardwares to store dates bigger than the
maximal date that is representable in the device's native format.
This prominently and very soon affects the hardware covered by the
rtc-mt6397 driver that can only natively store dates in the interval
1900-01-01 up to 2027-12-31. So to store the date 2028-01-01 00:00:00
to such a device, rtc_time64_to_tm() must do the right thing for
time=-2208988800.
Signed-off-by: Alexandre Mergnat <amergnat@baylibre.com>
Reviewed-by: Uwe Kleine-König <u.kleine-koenig@baylibre.com>
Link: https://lore.kernel.org/r/20250428-enable-rtc-v4-1-2b2f7e3f9349@baylibre.com
Signed-off-by: Alexandre Belloni <alexandre.belloni@bootlin.com>
When the regmap framework was introduced to this driver,
the PCF8563_REG_AMN register within the set_alarm function was
incorrectly changed to PCF8563_REG_SC.
The PCF8563_REG_SC register is the seconds register.
This caused alarm values to be written to the seconds register
when an alarm was set. Which means the alarm would not trigger
as expected and the seconds register would be overwritten
with an incorrect value.
Signed-off-by: Troy Mitchell <troymitchell988@gmail.com>
Link: https://lore.kernel.org/r/20250531-pcf8563-fix-alarm-v2-1-cac4b1716167@gmail.com
Signed-off-by: Alexandre Belloni <alexandre.belloni@bootlin.com>
The driver currently uses dev_err for messages that have a very low probability
of being read by the user as the error will probably never happen and the
systems with the RTC probably don't have any user able to read the message.
Moreover, the only user action after getting this message is the restart the
action so drop the level to dev_dbg.
Link: https://lore.kernel.org/r/20250525222153.1472917-1-alexandre.belloni@bootlin.com
Signed-off-by: Alexandre Belloni <alexandre.belloni@bootlin.com>
When an application sets and enables an alarm on Loongson RTC devices,
the alarm notification fails to propagate to userspace because the
ACPI event handler omits calling rtc_update_irq().
As a result, processes waiting via select() or poll() on RTC device
files fail to receive alarm notifications.
The ACPI interrupt is also triggered multiple times. In loongson_rtc_handler,
we need to clear TOY_MATCH0_REG to resolve this issue.
Fixes: 09471d8f5b ("rtc: loongson: clear TOY_MATCH0_REG in loongson_rtc_isr()")
Fixes: 1b733a9ebc ("rtc: Add rtc driver for the Loongson family chips")
Signed-off-by: Liu Dalin <liudalin@kylinsec.com.cn>
Reviewed-by: Binbin Zhou <zhoubinbin@loongson.cn>
Link: https://lore.kernel.org/r/20250509084416.7979-1-liudalin@kylinsec.com.cn
Signed-off-by: Alexandre Belloni <alexandre.belloni@bootlin.com>
On many Qualcomm platforms the PMIC RTC control and time registers are
read-only so that the RTC time can not be updated. Instead an offset
needs be stored in some machine-specific non-volatile memory, which a
driver can take into account.
On platforms where the offset is stored in a Qualcomm specific UEFI
variable the variables are also accessed in a non-standard way, which
means that the OS cannot assume that the variable service is available
by the time the driver probes.
Use the new 'qcom,uefi-rtc-info' property to determine whether to probe
defer until the UEFI offset becomes available so that the offset can be
used also when the RTC driver is built in or when a dependency of the
UEFI variable driver is built as a module (e.g. the driver for the SCM
interconnects).
Fixes: bba38b8748 ("rtc: pm8xxx: add support for uefi offset")
Reported-by: Rob Clark <robdclark@gmail.com>
Link: https://lore.kernel.org/lkml/CAF6AEGsfke=x0p1b2-uNX6DuQfRyEjVbJaxTbVLDT2YvSkGJbg@mail.gmail.com/
Signed-off-by: Johan Hovold <johan+linaro@kernel.org>
Link: https://lore.kernel.org/r/20250423075143.11157-3-johan+linaro@kernel.org
Signed-off-by: Alexandre Belloni <alexandre.belloni@bootlin.com>
