linux/Documentation/ABI
Linus Torvalds 5782fd14aa RTC for 4.11
Subsystem:
  - constify rtc_class_ops structures
 
 New driver:
  - STM32
 
 Drivers:
  - armada38x: fix errata, Armada 7K/8K support
  - ds3232: fix wakeup support
  - gemini: DT support
  - m48t86: huge cleanup and platform_data removal
  - mcp795: alarm support
  - sun6i: proper oscillator handling
  - tegra: proper clock handling
  - tps65910: calibration support
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Merge tag 'rtc-4.11' of git://git.kernel.org/pub/scm/linux/kernel/git/abelloni/linux

Pull RTC updates from Alexandre Belloni:
 "Subsystem:
   - constify rtc_class_ops structures

 New driver:
   - STM32

 Drivers:
   - armada38x: fix errata, Armada 7K/8K support
   - ds3232: fix wakeup support
   - gemini: DT support
   - m48t86: huge cleanup and platform_data removal
   - mcp795: alarm support
   - sun6i: proper oscillator handling
   - tegra: proper clock handling
   - tps65910: calibration support"

* tag 'rtc-4.11' of git://git.kernel.org/pub/scm/linux/kernel/git/abelloni/linux: (44 commits)
  rtc: ds3232: Call device_init_wakeup before device_register
  rtc: pcf2127: bulk read only date and time registers.
  rtc: armada38x: Add support for Armada 7K/8K
  rtc: armada38x: Prepare driver to manage different versions
  rtc: ds3232: Add regmap max_register definition.
  rtc: ds3232: Cleanup whitespace around register and bit definitions.
  rtc: m48t86: remove unused platform_data
  ARM: Orion5x: ts78xx: allow rtc-m48t86 to manage it's own resources
  ARM: Orion5x: ts78xx: remove RTC detection
  ARM: ep93xx: ts72xx: allow rtc-m48t86 to manage its own resources
  rtc: m48t86: verify that the RTC is actually present
  rtc: m48t86: add NVRAM support
  rtc: m48t86: allow driver to manage its resources
  rtc: m48t86: shorten register name defines
  bindings: rtc: correct wrong reference in required properties
  rtc: sun6i: Fix return value check in sun6i_rtc_clk_init()
  rtc: sun6i: extend test coverage
  rtc: sun6i: Fix compatibility with old DT binding
  rtc: snvs: add a missing write sync
  rtc: bq32000: add support to enable disable the trickle charge FET bypass
  ...
2017-02-27 19:59:21 -08:00
..
obsolete zram: remove obsolete sysfs attrs 2017-02-22 16:41:30 -08:00
removed rfkill: Remove obsolete "claim" sysfs interface 2016-02-24 09:04:24 +01:00
stable Documentation/ABI: Added ABI information for devspec and obppath. 2016-10-27 16:59:59 +02:00
testing RTC for 4.11 2017-02-27 19:59:21 -08:00
README docs: fix locations of several documents that got moved 2016-10-24 08:12:35 -02:00

README

This directory attempts to document the ABI between the Linux kernel and
userspace, and the relative stability of these interfaces.  Due to the
everchanging nature of Linux, and the differing maturity levels, these
interfaces should be used by userspace programs in different ways.

We have four different levels of ABI stability, as shown by the four
different subdirectories in this location.  Interfaces may change levels
of stability according to the rules described below.

The different levels of stability are:

  stable/
	This directory documents the interfaces that the developer has
	defined to be stable.  Userspace programs are free to use these
	interfaces with no restrictions, and backward compatibility for
	them will be guaranteed for at least 2 years.  Most interfaces
	(like syscalls) are expected to never change and always be
	available.

  testing/
	This directory documents interfaces that are felt to be stable,
	as the main development of this interface has been completed.
	The interface can be changed to add new features, but the
	current interface will not break by doing this, unless grave
	errors or security problems are found in them.  Userspace
	programs can start to rely on these interfaces, but they must be
	aware of changes that can occur before these interfaces move to
	be marked stable.  Programs that use these interfaces are
	strongly encouraged to add their name to the description of
	these interfaces, so that the kernel developers can easily
	notify them if any changes occur (see the description of the
	layout of the files below for details on how to do this.)

  obsolete/
  	This directory documents interfaces that are still remaining in
	the kernel, but are marked to be removed at some later point in
	time.  The description of the interface will document the reason
	why it is obsolete and when it can be expected to be removed.

  removed/
	This directory contains a list of the old interfaces that have
	been removed from the kernel.

Every file in these directories will contain the following information:

What:		Short description of the interface
Date:		Date created
KernelVersion:	Kernel version this feature first showed up in.
Contact:	Primary contact for this interface (may be a mailing list)
Description:	Long description of the interface and how to use it.
Users:		All users of this interface who wish to be notified when
		it changes.  This is very important for interfaces in
		the "testing" stage, so that kernel developers can work
		with userspace developers to ensure that things do not
		break in ways that are unacceptable.  It is also
		important to get feedback for these interfaces to make
		sure they are working in a proper way and do not need to
		be changed further.


How things move between levels:

Interfaces in stable may move to obsolete, as long as the proper
notification is given.

Interfaces may be removed from obsolete and the kernel as long as the
documented amount of time has gone by.

Interfaces in the testing state can move to the stable state when the
developers feel they are finished.  They cannot be removed from the
kernel tree without going through the obsolete state first.

It's up to the developer to place their interfaces in the category they
wish for it to start out in.


Notable bits of non-ABI, which should not under any circumstances be considered
stable:

- Kconfig.  Userspace should not rely on the presence or absence of any
  particular Kconfig symbol, in /proc/config.gz, in the copy of .config
  commonly installed to /boot, or in any invocation of the kernel build
  process.

- Kernel-internal symbols.  Do not rely on the presence, absence, location, or
  type of any kernel symbol, either in System.map files or the kernel binary
  itself.  See Documentation/process/stable-api-nonsense.rst.