linux-stable.git/drivers/rtc, branch v5.4.299 Linux kernel stable tree rtc: ds1307: handle oscillator stop flag (OSF) for ds1341 2025-08-28T14:21:35+00:00 Meagan Lloyd meaganlloyd@linux.microsoft.com 2025-08-20T23:06:04+00:00 7d5b525070f82b69601d99b2f6e250ca5a45cd35 [ Upstream commit 523923cfd5d622b8f4ba893fdaf29fa6adeb8c3e ] 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> [ Git was trying to insert the code above the ds_1388 case statement block (in each respective function) which don't exist in the v5.4.296 rtc-ds1307 driver, thus a manual fixup was required. ] Signed-off-by: Meagan Lloyd <meaganlloyd@linux.microsoft.com> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org> 
[ Upstream commit 523923cfd5d622b8f4ba893fdaf29fa6adeb8c3e ]

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>

[ Git was trying to insert the code above the ds_1388 case statement block (in
each respective function) which don't exist in the v5.4.296 rtc-ds1307 driver,
thus a manual fixup was required. ]
Signed-off-by: Meagan Lloyd <meaganlloyd@linux.microsoft.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
rtc: ds1307: remove clear of oscillator stop flag (OSF) in probe 2025-08-28T14:21:29+00:00 Meagan Lloyd meaganlloyd@linux.microsoft.com 2025-06-11T18:14:15+00:00 f3751c164156f4b99fe1d760008d389610cb8176 [ Upstream commit 48458654659c9c2e149c211d86637f1592470da5 ] 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> Signed-off-by: Sasha Levin <sashal@kernel.org> 
[ Upstream commit 48458654659c9c2e149c211d86637f1592470da5 ]

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>
Signed-off-by: Sasha Levin <sashal@kernel.org>
rtc: pcf8563: fix incorrect maximum clock rate handling 2025-08-28T14:21:22+00:00 Brian Masney bmasney@redhat.com 2025-07-10T15:20:25+00:00 75024aae0ee5b8f90798352aef022e11e939512a [ Upstream commit 906726a5efeefe0ef0103ccff5312a09080c04ae ] 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: a39a6405d5f94 ("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> Signed-off-by: Sasha Levin <sashal@kernel.org> 
[ Upstream commit 906726a5efeefe0ef0103ccff5312a09080c04ae ]

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: a39a6405d5f94 ("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>
Signed-off-by: Sasha Levin <sashal@kernel.org>
rtc: hym8563: fix incorrect maximum clock rate handling 2025-08-28T14:21:22+00:00 Brian Masney bmasney@redhat.com 2025-07-10T15:20:22+00:00 53ac364d1e334224f24a09fa58a875e23a5a658d [ Upstream commit d0a518eb0a692a2ab8357e844970660c5ea37720 ] 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: dcaf038493525 ("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> Signed-off-by: Sasha Levin <sashal@kernel.org> 
[ Upstream commit d0a518eb0a692a2ab8357e844970660c5ea37720 ]

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: dcaf038493525 ("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>
Signed-off-by: Sasha Levin <sashal@kernel.org>
rtc: ds1307: fix incorrect maximum clock rate handling 2025-08-28T14:21:21+00:00 Brian Masney bmasney@redhat.com 2025-07-10T15:20:21+00:00 0a9ac7f4244d3b51a234a567fd9c0256630ce047 [ Upstream commit cf6eb547a24af7ad7bbd2abe9c5327f956bbeae8 ] 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: 6c6ff145b3346 ("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> Signed-off-by: Sasha Levin <sashal@kernel.org> 
[ Upstream commit cf6eb547a24af7ad7bbd2abe9c5327f956bbeae8 ]

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: 6c6ff145b3346 ("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>
Signed-off-by: Sasha Levin <sashal@kernel.org>
rtc: test: Fix invalid format specifier. 2025-06-27T10:02:58+00:00 David Gow davidgow@google.com 2024-02-21T09:27:18+00:00 b9dc8b84b9e5375cd239b2c56dc2b8c765bbd431 commit 8a904a3caa88118744062e872ae90f37748a8fd8 upstream. 'days' is a s64 (from div_s64), and so should use a %lld specifier. This was found by extending KUnit's assertion macros to use gcc's __printf attribute. Fixes: 1d1bb12a8b18 ("rtc: Improve performance of rtc_time64_to_tm(). Add tests.") Signed-off-by: David Gow <davidgow@google.com> Tested-by: Guenter Roeck <linux@roeck-us.net> Reviewed-by: Justin Stitt <justinstitt@google.com> Acked-by: Alexandre Belloni <alexandre.belloni@bootlin.com> Signed-off-by: Shuah Khan <skhan@linuxfoundation.org> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org> 
commit 8a904a3caa88118744062e872ae90f37748a8fd8 upstream.

'days' is a s64 (from div_s64), and so should use a %lld specifier.

This was found by extending KUnit's assertion macros to use gcc's
__printf attribute.

Fixes: 1d1bb12a8b18 ("rtc: Improve performance of rtc_time64_to_tm(). Add tests.")
Signed-off-by: David Gow <davidgow@google.com>
Tested-by: Guenter Roeck <linux@roeck-us.net>
Reviewed-by: Justin Stitt <justinstitt@google.com>
Acked-by: Alexandre Belloni <alexandre.belloni@bootlin.com>
Signed-off-by: Shuah Khan <skhan@linuxfoundation.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
rtc: Make rtc_time64_to_tm() support dates before 1970 2025-06-27T10:02:58+00:00 Alexandre Mergnat amergnat@baylibre.com 2025-04-28T10:06:47+00:00 afef20f48875e578e3a90509074c7c02967333eb 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 <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> Signed-off-by: Uwe Kleine-König <u.kleine-koenig@baylibre.com> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org> 
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 <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>
Signed-off-by: Uwe Kleine-König <u.kleine-koenig@baylibre.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
rtc: Improve performance of rtc_time64_to_tm(). Add tests. 2025-06-27T10:02:58+00:00 Cassio Neri cassio.neri@gmail.com 2021-06-24T20:13:43+00:00 31d87dda792b819daf028488dcb4dd3206c2a9cd commit 1d1bb12a8b1805ddeef9793ebeb920179fb0fa38 upstream. The current implementation of rtc_time64_to_tm() contains unnecessary loops, branches and look-up tables. The new one uses an arithmetic-based algorithm appeared in [1] and is approximately 4.3 times faster (YMMV). The drawback is that the new code isn't intuitive and contains many 'magic numbers' (not unusual for this type of algorithm). However, [1] justifies all those numbers and, given this function's history, the code is unlikely to need much maintenance, if any at all. Add a KUnit test case that checks every day in a 160,000 years interval starting on 1970-01-01 against the expected result. Add a new config RTC_LIB_KUNIT_TEST symbol to give the option to run this test suite. [1] Neri, Schneider, "Euclidean Affine Functions and Applications to Calendar Algorithms". https://arxiv.org/abs/2102.06959 Signed-off-by: Cassio Neri <cassio.neri@gmail.com> Reported-by: kernel test robot <lkp@intel.com> Signed-off-by: Alexandre Belloni <alexandre.belloni@bootlin.com> Link: https://lore.kernel.org/r/20210624201343.85441-1-cassio.neri@gmail.com Signed-off-by: Uwe Kleine-König <u.kleine-koenig@baylibre.com> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org> 
commit 1d1bb12a8b1805ddeef9793ebeb920179fb0fa38 upstream.

The current implementation of rtc_time64_to_tm() contains unnecessary
loops, branches and look-up tables. The new one uses an arithmetic-based
algorithm appeared in [1] and is approximately 4.3 times faster (YMMV).

The drawback is that the new code isn't intuitive and contains many 'magic
numbers' (not unusual for this type of algorithm). However, [1] justifies
all those numbers and, given this function's history, the code is unlikely
to need much maintenance, if any at all.

Add a KUnit test case that checks every day in a 160,000 years interval
starting on 1970-01-01 against the expected result. Add a new config
RTC_LIB_KUNIT_TEST symbol to give the option to run this test suite.

[1] Neri, Schneider, "Euclidean Affine Functions and Applications to
Calendar Algorithms". https://arxiv.org/abs/2102.06959

Signed-off-by: Cassio Neri <cassio.neri@gmail.com>
Reported-by: kernel test robot <lkp@intel.com>
Signed-off-by: Alexandre Belloni <alexandre.belloni@bootlin.com>
Link: https://lore.kernel.org/r/20210624201343.85441-1-cassio.neri@gmail.com
Signed-off-by: Uwe Kleine-König <u.kleine-koenig@baylibre.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
rtc: Fix offset calculation for .start_secs < 0 2025-06-27T10:02:48+00:00 Alexandre Mergnat amergnat@baylibre.com 2025-04-28T10:06:48+00:00 55d4b2734f48cdb20cdd272b580d1f3a4ed7d6e2 [ Upstream commit fe9f5f96cfe8b82d0f24cbfa93718925560f4f8d ] 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 <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> Signed-off-by: Sasha Levin <sashal@kernel.org> 
[ Upstream commit fe9f5f96cfe8b82d0f24cbfa93718925560f4f8d ]

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 <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>
Signed-off-by: Sasha Levin <sashal@kernel.org>
rtc: sh: assign correct interrupts with DT 2025-06-27T10:02:48+00:00 Wolfram Sang wsa+renesas@sang-engineering.com 2025-02-27T13:42:56+00:00 5023b76466ce3bd6d5074fd4dffd33b10d9fe844 [ Upstream commit 8f2efdbc303fe7baa83843d3290dd6ea5ba3276c ] The DT bindings for this driver define the interrupts in the order as they are numbered in the interrupt controller. The old platform_data, however, listed them in a different order. So, for DT based platforms, they are mixed up. Assign them specifically for DT, so we can keep the bindings stable. After the fix, 'rtctest' passes again on the Renesas Genmai board (RZ-A1 / R7S72100). Fixes: dab5aec64bf5 ("rtc: sh: add support for rza series") Signed-off-by: Wolfram Sang <wsa+renesas@sang-engineering.com> Link: https://lore.kernel.org/r/20250227134256.9167-11-wsa+renesas@sang-engineering.com Signed-off-by: Alexandre Belloni <alexandre.belloni@bootlin.com> Signed-off-by: Sasha Levin <sashal@kernel.org> 
[ Upstream commit 8f2efdbc303fe7baa83843d3290dd6ea5ba3276c ]

The DT bindings for this driver define the interrupts in the order as
they are numbered in the interrupt controller. The old platform_data,
however, listed them in a different order. So, for DT based platforms,
they are mixed up. Assign them specifically for DT, so we can keep the
bindings stable. After the fix, 'rtctest' passes again on the Renesas
Genmai board (RZ-A1 / R7S72100).

Fixes: dab5aec64bf5 ("rtc: sh: add support for rza series")
Signed-off-by: Wolfram Sang <wsa+renesas@sang-engineering.com>
Link: https://lore.kernel.org/r/20250227134256.9167-11-wsa+renesas@sang-engineering.com
Signed-off-by: Alexandre Belloni <alexandre.belloni@bootlin.com>
Signed-off-by: Sasha Levin <sashal@kernel.org>