linux.git/drivers/rtc, branch master

Merge tag 'rtc-7.2' of git://git.kernel.org/pub/scm/linux/kernel/git/abelloni/linux

2026-06-27T18:00:18+00:00

Pull RTC updates from Alexandre Belloni:
 "Most of the work and improvements are for features of the m41t93.

  The ds1307 also gets support for OSF (Oscillator Stop Flag) for
  new variants.

  The pcap driver is being removed as the Motorola EZX support was
  removed a while ago.

  Subsystem:
   - add rtc_read_next_alarm() to read next expiring timer

  Drivers:
   - ds1307: handle OSF for ds1337/ds1339/ds3231, add clock provider for
     ds1307, fix wday for rx8130
   - m41t93: DT support, alarm, clock provider, watchdog support
   - mv: add suspend/resume support for wakeup
   - pcap: remove driver
   - renesas-rtca3: many fixes"

* tag 'rtc-7.2' of git://git.kernel.org/pub/scm/linux/kernel/git/abelloni/linux: (36 commits)
  rtc: ds1307: update reference to removed CONFIG_RTC_DRV_DS1307_HWMON
  platform/x86: amd-pmc: Fix S0i3 wakeup with alarmtimer
  rtc: s35390a: fix typo in comment
  rtc: cmos: unregister HPET IRQ handler on probe failure
  rtc: ds1307: Fix off-by-one issue with wday for rx8130
  dt-bindings: rtc: ds1307: Add epson,rx8901
  rtc: bq32000: add delay between RTC reads
  rtc: m41t93: Add watchdog support
  rtc: m41t93: Add square wave clock provider support
  rtc: m41t93: Add alarm support
  rtc: m41t93: migrate to regmap api for register access
  rtc: m41t93: add device tree support
  dt-bindings: rtc: Add ST m41t93
  rtc: ds1307: add support for clock provider in ds1307
  rtc: mv: add suspend/resume support for wakeup
  rtc: aspeed: add AST2700 compatible
  dt-bindings: rtc: add ASPEED AST2700 compatible
  rtc: interface: fix typos in rtc_handle_legacy_irq() documentation
  rtc: msc313: fix NULL deref in shared IRQ handler at probe
  rtc: remove unused pcap driver
  ...

rtc: ds1307: update reference to removed CONFIG_RTC_DRV_DS1307_HWMON

2026-06-25T12:44:39+00:00

The CONFIG_RTC_DRV_DS1307_HWMON macro was removed in favor of
CONFIG_HWMON in commit 6b583a64fd1e ("rtc: ds1307: simplify hwmon
config"), but a reference to it remained in a comment. Correct this
reference.

Discovered while searching for CONFIG_* symbols referenced in code but
not defined in any Kconfig file.

Signed-off-by: Ethan Nelson-Moore 
Link: https://patch.msgid.link/20260610054723.261008-1-enelsonmoore@gmail.com
Signed-off-by: Alexandre Belloni

rtc: s35390a: fix typo in comment

2026-06-25T06:57:52+00:00

Fix trivial typo

Link: https://patch.msgid.link/20260624204223.1479003-1-alexandre.belloni@bootlin.com
Signed-off-by: Alexandre Belloni

rtc: cmos: unregister HPET IRQ handler on probe failure

2026-06-24T21:49:00+00:00

cmos_do_probe() registers cmos_interrupt() as the HPET RTC IRQ
handler before requesting the RTC IRQ and registering the RTC
device. If either request_irq() or devm_rtc_register_device()
fails afterwards, the error path leaves the HPET RTC IRQ handler
installed. This leaves a stale handler behind and make a later
hpet_register_irq_handler() fail with -EBUSY.

Track whether the HPET handler was registered successfully and
undo the registration on the probe error path. Also mask the HPET
RTC IRQ bits to match the normal shutdown cleanup.

Fixes: 9d8af78b0797 ("rtc: add HPET RTC emulation to RTC_DRV_CMOS")
Signed-off-by: Haoxiang Li 
Link: https://patch.msgid.link/20260623100848.2127281-1-haoxiang_li2024@163.com
Signed-off-by: Alexandre Belloni

rtc: ds1307: Fix off-by-one issue with wday for rx8130

2026-06-24T21:40:10+00:00

The RTC represent each weekday with a individual bit set in the WDAY
register, where the 0th bit represent the first day of the week and the
6th bit represents the last day of the week. For each passed day the
chip performs a rotary-left-shift by one to advance the weekday by one.

The tm_wday field represent weekdays by a value in the range of 0-6.

The fls() function return the bit index of the last bit set. To handle
when there are no bits set it will return 0, and if the 0th bit is set
it will return 1, and if the 1st bit is set it will return 2, and so on.

In order to make the result of the fls() function fall into the expected
range of 0-6 (instead of 1-7) this patch subtracts one from the result
(which matches how the value is written in ds1307_set_time()).

Fixes: 204756f016726 ("rtc: ds1307: Fix wday settings for rx8130")
Reviewed-by: Nobuhiro Iwamatsu 
Signed-off-by: Fredrik M Olsson 
Link: https://patch.msgid.link/20260520-ds1307-rx8901-add-v2-2-e069ea32e1db@axis.com
Signed-off-by: Alexandre Belloni

rtc: bq32000: add delay between RTC reads

2026-06-24T21:25:09+00:00

When the RTC is used on systems without a interrupt line, userspace
tools like `hwclock` fall back to a frequent polling loop to synchronize
with the edge of the next second.

On the BQ32000, this aggressive polling can temporarly lock the register
refresh cycle, because the continuous transfers prevent the hardware from
updating the buffer. This results in stale data reads or select() timeouts
in userspace.

This patch introduces a delay before reading the RTC registers in order to
provide a sufficient idle time for the hardware to sync with the register
buffer.

Signed-off-by: Adriana Stancu 
Link: https://patch.msgid.link/20260416142151.3385827-1-adriana@arista.com
Signed-off-by: Alexandre Belloni

rtc: m41t93: Add watchdog support

2026-06-24T21:12:11+00:00

Implement watchdog feature for m41t93 rtc with 1s resolution.
Implement alarm only support (WDIOF_ALARMONLY) in this commit.
Define start, stop, ping, and set_timeout callbacks as needed
by the watchdog framework.

Use selftests/watchdog/watchdog-test kselftest for testing.
Observed IRQ pin(12) of rtc chip going low after late pinging
the watchdog.

Signed-off-by: Akhilesh Patil 
Link: https://patch.msgid.link/77c2e9f4ab0811a919595d7a5476b00abd1c2803.1758379856.git.akhilesh@ee.iitb.ac.in
Signed-off-by: Alexandre Belloni

rtc: m41t93: Add square wave clock provider support

2026-06-24T21:11:10+00:00

Implement support to configure square wave output (SQW) of m41t93 rtc
via common clock framework clock provider api. Add clock provider
callbacks to control output frequency ranging from 1Hz to 32KHz as
supported by this rtc chip.

Use clock framework debugfs interface or clock consumer DT node to test.
Tested by measuring various frequencies on pull-up connected SWQ(7) pin
of m41t93 rtc chip using logic analyzer.

Signed-off-by: Akhilesh Patil 
Link: https://patch.msgid.link/a8c4d3741be4e9dfa52c57cbd653f561ba4ed934.1758379856.git.akhilesh@ee.iitb.ac.in
Signed-off-by: Alexandre Belloni

rtc: m41t93: Add alarm support

2026-06-24T21:08:54+00:00

Implement alarm feature for rtc-m41t93 by adding necessary
callbacks - set_alarm, read_alarm and alarm_irq_enable.
Enable support to configure alarm 1 out of 2 alarms present in this rtc.
Support only alarm configuration in this commit. This commit does not
implement alarm irq handling.

Use selftests/rtc/rtctest for testing. Tested by observing IRQ pin
(pin 12 of SOX18 package) on logic analyzer going low after alarm
condition is met.

Signed-off-by: Akhilesh Patil 
Link: https://patch.msgid.link/1b272ff1a5392d5eb76e129a4785ac8424763356.1758379856.git.akhilesh@ee.iitb.ac.in
Signed-off-by: Alexandre Belloni

rtc: m41t93: migrate to regmap api for register access

2026-06-24T21:08:39+00:00

Adapt driver to use regmap api with spi bus instead of direct spi
subsystem calls to access device registers. Simplify and standardize the
register interactions using more abstract and bus agnostic regmap api
to reduce code duplication and improve maintainability. Define spi regmap
config suitable for m41t93 spi bus protocol to achieve same transactions on
spi bus.

Tested on TI am62x sk board with m41t93 rtc chip connected over spi0.
Validated set and get time using hwclock tool and verified spi bus
transfers using logic analyzer.

Signed-off-by: Akhilesh Patil 
Link: https://patch.msgid.link/180f9b6c3ee7c490fe3537c2d50a92cec359e4cd.1758379856.git.akhilesh@ee.iitb.ac.in
Signed-off-by: Alexandre Belloni