linux-toradex.git/include/linux/rtc.h, branch v5.12-rc5

rtc: introduce features bitfield

2021-01-16T22:19:26+00:00

Introduce a bitfield to allow the drivers to announce the available
features for an RTC.

The main use case would be to better handle alarms, that could be present
or not or have a minute resolution or may need a correct week day to be set.

Use the newly introduced RTC_FEATURE_ALARM bit to then test whether alarms
are available instead of relying on the presence of ops->set_alarm.

Signed-off-by: Alexandre Belloni 
Link: https://lore.kernel.org/r/20210110231752.1418816-2-alexandre.belloni@bootlin.com

Merge tag 'rtc-5.11' of git://git.kernel.org/pub/scm/linux/kernel/git/abelloni/linux

2020-12-20T18:12:06+00:00

Pull RTC updates from Alexandre Belloni:
 "Subsystem:

   - Remove nvram ABI. There was no complaints about the deprecation for
     the last 3 years.

   - Improve RTC device allocation and registration

   - Now available for ARCH=um

  Drivers:

   - at91rm9200: correction and sam9x60 support

   - ds1307: improve ACPI support

   - mxc: now DT only

   - pcf2127: watchdog support now needs the reset-source property

   - pcf8523: set range

   - rx6110: i2c support"

* tag 'rtc-5.11' of git://git.kernel.org/pub/scm/linux/kernel/git/abelloni/linux: (43 commits)
  rtc: pcf2127: only use watchdog when explicitly available
  dt-bindings: rtc: add reset-source property
  rtc: fix RTC removal
  rtc: s3c: Remove dead code related to periodic tick handling
  rtc: s3c: Disable all enable (RTC, tick) bits in the probe
  rtc: ep93xx: Fix NULL pointer dereference in ep93xx_rtc_read_time
  rtc: test: remove debug message
  rtc: mxc{,_v2}: enable COMPILE_TEST
  rtc: enable RTC framework on ARCH=um
  rtc: pcf8523: use BIT
  rtc: pcf8523: set range
  rtc: pcf8523: switch to devm_rtc_allocate_device
  rtc: destroy mutex when releasing the device
  rtc: shrink devm_rtc_allocate_device()
  rtc: rework rtc_register_device() resource management
  rtc: nvmem: emit an error message when nvmem registration fails
  rtc: add devm_ prefix to rtc_nvmem_register()
  rtc: nvmem: remove nvram ABI
  Documentation: list RTC devres helpers in devres.rst
  rtc: omap: use devm_pinctrl_register()
  ...

ntp: Make the RTC sync offset less obscure

2020-12-11T09:40:53+00:00

The current RTC set_offset_nsec value is not really intuitive to
understand. 

  tsched       twrite(t2.tv_sec - 1) 	 t2 (seconds increment)

The offset is calculated from twrite based on the assumption that t2 -
twrite == 1s. That means for the MC146818 RTC the offset needs to be
negative so that the write happens 500ms before t2.

It's easier to understand when the whole calculation is based on t2. That
avoids negative offsets and the meaning is obvious:

 t2 - twrite:     The time defined by the chip when seconds increment
      		  after the write.

 twrite - tsched: The time for the transport to the point where the chip
 	  	  is updated. 

==> set_offset_nsec =  t2 - tsched
    ttransport      =  twrite - tsched
    tRTCinc         =  t2 - twrite
==> set_offset_nsec =  ttransport + tRTCinc

tRTCinc is a chip property and can be obtained from the data sheet.

ttransport depends on how the RTC is connected. It is close to 0 for
directly accessible RTCs. For RTCs behind a slow bus, e.g. i2c, it's the
time required to send the update over the bus. This can be estimated or
even calibrated, but that's a different problem.

Adjust the implementation and update comments accordingly.

Signed-off-by: Thomas Gleixner 
Acked-by: Alexandre Belloni 
Link: https://lore.kernel.org/r/20201206220542.263204937@linutronix.de

ntp, rtc: Move rtc_set_ntp_time() to ntp code

2020-12-11T09:40:52+00:00

rtc_set_ntp_time() is not really RTC functionality as the code is just a
user of RTC. Move it into the NTP code which allows further cleanups.

Requested-by: Alexandre Belloni 
Signed-off-by: Thomas Gleixner 
Reviewed-by: Jason Gunthorpe 
Acked-by: Alexandre Belloni 
Link: https://lore.kernel.org/r/20201206220542.166871172@linutronix.de

rtc: rework rtc_register_device() resource management

2020-11-19T11:50:12+00:00

rtc_register_device() is a managed interface but it doesn't use devres
by itself - instead it marks an rtc_device as "registered" and the devres
callback for devm_rtc_allocate_device() takes care of resource release.

This doesn't correspond with the design behind devres where managed
structures should not be aware of being managed. The correct solution
here is to register a separate devres callback for unregistering the
device.

While at it: rename rtc_register_device() to devm_rtc_register_device()
and add it to the list of managed interfaces in devres.rst. This way we
can avoid any potential confusion of driver developers who may expect
there to exist a corresponding unregister function.

Signed-off-by: Bartosz Golaszewski 
Signed-off-by: Alexandre Belloni 
Link: https://lore.kernel.org/r/20201109163409.24301-8-brgl@bgdev.pl

rtc: add devm_ prefix to rtc_nvmem_register()

2020-11-19T11:50:11+00:00

rtc_nvmem_register() is a managed interface. It doesn't require any
release function to be called at driver detach. To avoid confusing
driver authors, let's rename it to devm_rtc_nvmem_register() and add it
to the list of managed interfaces in Documentation/.

Signed-off-by: Bartosz Golaszewski 
Signed-off-by: Alexandre Belloni 
Link: https://lore.kernel.org/r/20201109163409.24301-6-brgl@bgdev.pl

rtc: nvmem: remove nvram ABI

2020-11-19T11:50:11+00:00

The nvram sysfs attributes have been deprecated at least since v4.13, more
than 3 years ago and nobody ever complained about the deprecation warning.

Remove the sysfs attributes now.

[Bartosz: remove the declaration of rtc_nvmem_unregister()]

Signed-off-by: Alexandre Belloni 
Signed-off-by: Bartosz Golaszewski 
Link: https://lore.kernel.org/r/20201109163409.24301-5-brgl@bgdev.pl

rtc: cleanup obsolete comment about struct rtc_class_ops

2020-07-16T11:35:25+00:00

Commit ea369ea6d828 ("rtc: remove .open() and .release()") removes
open/release callback from struct rtc_class_ops.

Also commit 80d4bb515b78 ("RTC: Cleanup rtc_class_ops->irq_set_state")
and commit 696160fec162 ("RTC: Cleanup rtc_class_ops->irq_set_freq()")
removes irq callbacks.

So, just remove related comments so that readers will not be confused.

Signed-off-by: Misono Tomohiro 
Signed-off-by: Alexandre Belloni 
Link: https://lore.kernel.org/r/20200710080003.7986-1-misono.tomohiro@jp.fujitsu.com

rtc: remove rtc_time_to_tm and rtc_tm_to_time

2020-04-02T16:47:30+00:00

There are no callers of the 32bit versions of rtc_time conversion
functions, drop them.

Link: https://lore.kernel.org/r/20200330201510.861217-1-alexandre.belloni@bootlin.com
Signed-off-by: Alexandre Belloni

rtc: rv3029: let the core handle rtc range

2019-12-18T09:38:07+00:00

Despite the comment, the RV3029 uses a 7bit BCD register for the year,
making 2079 the last supported year.

Link: https://lore.kernel.org/r/20191214221022.622482-14-alexandre.belloni@bootlin.com
Signed-off-by: Alexandre Belloni