linux-stable.git/drivers/rtc, branch linux-6.14.y

rtc: Fix offset calculation for .start_secs < 0

2025-06-10T11:15:56+00:00

commit fe9f5f96cfe8b82d0f24cbfa93718925560f4f8d upstream.

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: 989515647e783 ("rtc: Add one offset seconds to expand RTC range")
Signed-off-by: Alexandre Mergnat 
Reviewed-by: Uwe Kleine-König 
Link: https://lore.kernel.org/r/20250428-enable-rtc-v4-2-2b2f7e3f9349@baylibre.com
Signed-off-by: Alexandre Belloni 
Signed-off-by: Uwe Kleine-König 
Signed-off-by: Greg Kroah-Hartman

rtc: Make rtc_time64_to_tm() support dates before 1970

2025-06-10T11:15:56+00:00

commit 7df4cfef8b351fec3156160bedfc7d6d29de4cce upstream.

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 
Reviewed-by: Uwe Kleine-König 
Link: https://lore.kernel.org/r/20250428-enable-rtc-v4-1-2b2f7e3f9349@baylibre.com
Signed-off-by: Alexandre Belloni 
Signed-off-by: Uwe Kleine-König 
Signed-off-by: Greg Kroah-Hartman

rtc: ds1307: stop disabling alarms on probe

2025-05-29T09:12:54+00:00

[ Upstream commit dcec12617ee61beed928e889607bf37e145bf86b ]

It is a bad practice to disable alarms on probe or remove as this will
prevent alarms across reboots.

Link: https://lore.kernel.org/r/20250303223744.1135672-1-alexandre.belloni@bootlin.com
Signed-off-by: Alexandre Belloni 
Signed-off-by: Sasha Levin

rtc: rv3032: fix EERD location

2025-05-29T09:12:40+00:00

[ Upstream commit b0f9cb4a0706b0356e84d67e48500b77b343debe ]

EERD is bit 2 in CTRL1

Link: https://lore.kernel.org/r/20250306214243.1167692-1-alexandre.belloni@bootlin.com
Signed-off-by: Alexandre Belloni 
Signed-off-by: Sasha Levin

rtc: pcf85063: do a SW reset if POR failed

2025-05-02T06:02:04+00:00

[ Upstream commit 2b7cbd98495f6ee4cd6422fe77828a19e9edf87f ]

Power-on Reset has a documented issue in PCF85063, refer to its datasheet,
section "Software reset":

"There is a low probability that some devices will have corruption of the
registers after the automatic power-on reset if the device is powered up
with a residual VDD level. It is required that the VDD starts at zero volts
at power up or upon power cycling to ensure that there is no corruption of
the registers. If this is not possible, a reset must be initiated after
power-up (i.e. when power is stable) with the software reset command"

Trigger SW reset if there is an indication that POR has failed.

Link: https://www.nxp.com/docs/en/data-sheet/PCF85063A.pdf
Signed-off-by: Lukas Stockmann 
Signed-off-by: Alexander Sverdlin 
Link: https://lore.kernel.org/r/20250120093451.30778-1-alexander.sverdlin@siemens.com
Signed-off-by: Alexandre Belloni 
Signed-off-by: Sasha Levin

rtc: renesas-rtca3: Disable interrupts only if the RTC is enabled

2025-04-10T12:44:37+00:00

[ Upstream commit 27b2fcbd6b98204b0dce62e9aa9540ca0a2b70f1 ]

If the RTC is not enabled and the code attempts to disable the interrupt,
the readb_poll_timeout_atomic() function in the
rtca3_alarm_irq_set_helper() may timeout, leading to probe failures.
This issue is reproducible on some devices because the initial values of
the PIE and AIE bits in the RCR1 register are undefined.

To prevent probe failures in this scenario, disable RTC interrupts only
when the RTC is actually enabled.

Fixes: d4488377609e ("rtc: renesas-rtca3: Add driver for RTCA-3 available on Renesas RZ/G3S SoC")
Signed-off-by: Claudiu Beznea 
Link: https://lore.kernel.org/r/20250205095519.2031742-1-claudiu.beznea.uj@bp.renesas.com
Signed-off-by: Alexandre Belloni 
Signed-off-by: Sasha Levin

Merge tag 'rtc-6.14' of git://git.kernel.org/pub/scm/linux/kernel/git/abelloni/linux

2025-01-31T01:50:02+00:00

Pull RTC updates from Alexandre Belloni:
 "Not much this cycle, there are multiple small fixes.

  Core:
   - use boolean values with device_init_wakeup()

  Drivers:
   - pcf2127: add BSM support
   - pcf85063: fix possible out of bounds write"

* tag 'rtc-6.14' of git://git.kernel.org/pub/scm/linux/kernel/git/abelloni/linux:
  rtc: pcf2127: add BSM support
  rtc: Remove hpet_rtc_dropped_irq()
  dt-bindings: rtc: mxc: Document fsl,imx31-rtc
  rtc: stm32: Use syscon_regmap_lookup_by_phandle_args
  rtc: zynqmp: Fix optional clock name property
  rtc: loongson: clear TOY_MATCH0_REG in loongson_rtc_isr()
  rtc: pcf85063: fix potential OOB write in PCF85063 NVMEM read
  rtc: tps6594: Fix integer overflow on 32bit systems
  rtc: use boolean values with device_init_wakeup()
  rtc: RTC_DRV_SPEAR should not default to y when compile-testing

rtc: pcf2127: add BSM support

2025-01-28T23:42:29+00:00

The pcf2127 encodes BSM, BLD and power fail detection in the same set of
bits so it is necessary to do some calculation when changing BSM to keep
the rest of the configuration as-is. However, when BSM is disabled, there
is no configuration with BLD enabled so this will be lost when coming back
to a mode with BSM enabled.

Link: https://lore.kernel.org/r/20250127162728.86234-1-alexandre.belloni@bootlin.com
Signed-off-by: Alexandre Belloni

rtc: Remove hpet_rtc_dropped_irq()

2025-01-13T22:07:18+00:00

hpet_rtc_dropped_irq() has been unused since
commit f52ef24be21a ("rtc/alpha: remove legacy rtc driver")

Remove it in rtc, and x86 hpet code.

Signed-off-by: Dr. David Alan Gilbert 
Acked-by: Borislav Petkov (AMD) 
Link: https://lore.kernel.org/r/20241215022356.181625-1-linux@treblig.org
Signed-off-by: Alexandre Belloni

rtc: stm32: Use syscon_regmap_lookup_by_phandle_args

2025-01-13T08:33:39+00:00

Use syscon_regmap_lookup_by_phandle_args() which is a wrapper over
syscon_regmap_lookup_by_phandle() combined with getting the syscon
argument.  Except simpler code this annotates within one line that given
phandle has arguments, so grepping for code would be easier.

There is also no real benefit in printing errors on missing syscon
argument, because this is done just too late: runtime check on
static/build-time data.  Dtschema and Devicetree bindings offer the
static/build-time check for this already.

Signed-off-by: Krzysztof Kozlowski 
Link: https://lore.kernel.org/r/20250111185405.183824-1-krzysztof.kozlowski@linaro.org
Signed-off-by: Alexandre Belloni