linux-stable.git/drivers/rtc, branch v5.16.3

rtc: pxa: fix null pointer dereference

2022-01-27T11:02:58+00:00

commit 34127b3632b21e5c391756e724b1198eb9917981 upstream.

With the latest stable kernel versions the rtc on the PXA based
Zaurus does not work, when booting I see the following kernel messages:

pxa-rtc pxa-rtc: failed to find rtc clock source
pxa-rtc pxa-rtc: Unable to init SA1100 RTC sub-device
pxa-rtc: probe of pxa-rtc failed with error -2
hctosys: unable to open rtc device (rtc0)

I think this is because commit f2997775b111 ("rtc: sa1100: fix possible
race condition") moved the allocation of the rtc_device struct out of
sa1100_rtc_init and into sa1100_rtc_probe. This means that pxa_rtc_probe
also needs to do allocation for the rtc_device struct, otherwise
sa1100_rtc_init will try to dereference a null pointer. This patch adds
that allocation by copying how sa1100_rtc_probe in
drivers/rtc/rtc-sa1100.c does it; after the IRQs are set up a managed
rtc_device is allocated.

I've tested this patch with `qemu-system-arm -machine akita` and with a
real Zaurus SL-C1000 applied to 4.19, 5.4, and 5.10.

Signed-off-by: Laurence de Bruxelles 
Fixes: f2997775b111 ("rtc: sa1100: fix possible race condition")
Signed-off-by: Alexandre Belloni 
Link: https://lore.kernel.org/r/20220101154149.12026-1-lfdebrux@gmail.com
Signed-off-by: Greg Kroah-Hartman

rtc: Move variable into switch case statement

2022-01-27T11:02:58+00:00

commit ba52eac083e1598e748811ff58d259f77e4c5c4d upstream.

When building with automatic stack variable initialization, GCC 12
complains about variables defined outside of switch case statements.
Move the variable into the case that uses it, which silences the warning:

drivers/rtc/dev.c: In function 'rtc_dev_ioctl':
drivers/rtc/dev.c:394:30: warning: statement will never be executed [-Wswitch-unreachable]
  394 |                         long offset;
      |                              ^~~~~~

Fixes: 6a8af1b6568a ("rtc: add parameter ioctl")
Signed-off-by: Kees Cook 
Reviewed-by: Gustavo A. R. Silva 
Signed-off-by: Alexandre Belloni 
Link: https://lore.kernel.org/r/20211209043915.1378393-1-keescook@chromium.org
Signed-off-by: Greg Kroah-Hartman

rtc: cmos: take rtc_lock while reading from CMOS

2022-01-27T11:01:19+00:00

commit 454f47ff464325223129b9b5b8d0b61946ec704d upstream.

Reading from the CMOS involves writing to the index register and then
reading from the data register. Therefore access to the CMOS has to be
serialized with rtc_lock. This invocation of CMOS_READ was not
serialized, which could cause trouble when other code is accessing CMOS
at the same time.

Use spin_lock_irq() like the rest of the function.

Nothing in kernel modifies the RTC_DM_BINARY bit, so there could be a
separate pair of spin_lock_irq() / spin_unlock_irq() before doing the
math.

Signed-off-by: Mateusz Jończyk 
Reviewed-by: Nobuhiro Iwamatsu 
Cc: Alessandro Zummo 
Cc: Alexandre Belloni 
Cc: stable@vger.kernel.org
Signed-off-by: Alexandre Belloni 
Link: https://lore.kernel.org/r/20211210200131.153887-2-mat.jonczyk@o2.pl
Signed-off-by: Greg Kroah-Hartman

Merge tag 'rtc-5.16' of git://git.kernel.org/pub/scm/linux/kernel/git/abelloni/linux

2021-11-12T19:44:31+00:00

Pull RTC updates from Alexandre Belloni:
 "This includes new ioctls to get and set parameters and in particular
  the backup switch mode that is needed for some RTCs to actually enable
  the backup voltage (and have a useful RTC).

  The same interface can also be used to get the actual features
  supported by the RTC so userspace has a better way than trying and
  failing.

  Summary:

  Subsystem:
   - Add new ioctl to get and set extra RTC parameters, this includes
     backup switch mode
   - Expose available features to userspace, in particular, when alarmas
     have a resolution of one minute instead of a second.
   - Let the core handle those alarms with a minute resolution

  New driver:
   - MSTAR MSC313 RTC

  Drivers:
   - Add SPI ID table where necessary
   - Add BSM support for rv3028, rv3032 and pcf8523
   - s3c: set RTC range
   - rx8025: set range, implement .set_offset and .read_offset"

* tag 'rtc-5.16' of git://git.kernel.org/pub/scm/linux/kernel/git/abelloni/linux: (50 commits)
  rtc: rx8025: use .set_offset/.read_offset
  rtc: rx8025: use rtc_add_group
  rtc: rx8025: clear RTC_FEATURE_ALARM when alarm are not supported
  rtc: rx8025: set range
  rtc: rx8025: let the core handle the alarm resolution
  rtc: rx8025: switch to devm_rtc_allocate_device
  rtc: ab8500: let the core handle the alarm resolution
  rtc: ab-eoz9: support UIE when available
  rtc: ab-eoz9: use RTC_FEATURE_UPDATE_INTERRUPT
  rtc: rv3032: let the core handle the alarm resolution
  rtc: s35390a: let the core handle the alarm resolution
  rtc: handle alarms with a minute resolution
  rtc: pcf85063: silence cppcheck warning
  rtc: rv8803: fix writing back ctrl in flag register
  rtc: s3c: Add time range
  rtc: s3c: Extract read/write IO into separate functions
  rtc: s3c: Remove usage of devm_rtc_device_register()
  rtc: tps80031: Remove driver
  rtc: sun6i: Allow probing without an early clock provider
  rtc: pcf8523: add BSM support
  ...

rtc: rx8025: use .set_offset/.read_offset

2021-11-09T23:45:57+00:00

The driver has its own sysfs file to adjust the clock. Fortunately, it is
already in pbb, however, the sign it expects is the opposite of what the
RTC core does (which actually aligns with the RTC).

Signed-off-by: Alexandre Belloni 
Link: https://lore.kernel.org/r/20211107225458.111068-12-alexandre.belloni@bootlin.com

rtc: rx8025: use rtc_add_group

2021-11-09T23:45:57+00:00

Remove open coded sysfs registration by using rtc_add_group.

Signed-off-by: Alexandre Belloni 
Link: https://lore.kernel.org/r/20211107225458.111068-11-alexandre.belloni@bootlin.com

rtc: rx8025: clear RTC_FEATURE_ALARM when alarm are not supported

2021-11-09T23:45:57+00:00

Clear RTC_FEATURE_ALARM to signal alarms are not supported to the core
instead of checking client->irq.

Signed-off-by: Alexandre Belloni 
Link: https://lore.kernel.org/r/20211107225458.111068-10-alexandre.belloni@bootlin.com

rtc: rx8025: set range

2021-11-09T23:45:57+00:00

Set the RTC range, it is a classic BCD RTC, with 00 being a leap
year. Let the core handle range checking.

Signed-off-by: Alexandre Belloni 
Link: https://lore.kernel.org/r/20211107225458.111068-9-alexandre.belloni@bootlin.com

rtc: rx8025: let the core handle the alarm resolution

2021-11-09T23:45:57+00:00

Tell the RTC core UIE are not supported because the resolution of the alarm
is a minute.

Signed-off-by: Alexandre Belloni 
Link: https://lore.kernel.org/r/20211107225458.111068-8-alexandre.belloni@bootlin.com

rtc: rx8025: switch to devm_rtc_allocate_device

2021-11-09T23:45:57+00:00

Switch to devm_rtc_allocate_device/devm_rtc_register_device, this allows
for further improvement of the driver.

Signed-off-by: Alexandre Belloni 
Link: https://lore.kernel.org/r/20211107225458.111068-7-alexandre.belloni@bootlin.com