linux/Documentation/ABI
Linus Torvalds 8649efb2f8 power supply and reset changes for the v5.2 series
Core:
  * Add over-current health state
  * Add standard, adaptive and custom charge types
  * Add new properties for start/end charge threshold
 
 New Drivers / Hardware:
  * UCS1002 Programmable USB Port Power Controller
  * Ingenic JZ47xx Battery Fuel Gauge
  * AXP20x USB Power: Add AXP813 support
  * AT91 poweroff: Add SAM9X60 support
  * OLPC battery: Add XO-1.5 and XO-1.75 support
 
 Misc. Changes:
  * syscon-reboot: support mask property
  * AXP288 fuel gauge: Blacklist ACEPC T8/T11
   - Looks like some vendor thought it's a good idea to
     build a desktop system with a fuel gauge, that slowly
     "discharges"...
  * cpcap-battery: Fix calculation errors
  * misc. fixes
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Merge tag 'for-v5.2' of git://git.kernel.org/pub/scm/linux/kernel/git/sre/linux-power-supply

Pull power supply and reset updates from Sebastian Reichel:
 "Core:
   - Add over-current health state
   - Add standard, adaptive and custom charge types
   - Add new properties for start/end charge threshold

  New Drivers / Hardware:
   - UCS1002 Programmable USB Port Power Controller
   - Ingenic JZ47xx Battery Fuel Gauge
   - AXP20x USB Power: Add AXP813 support
   - AT91 poweroff: Add SAM9X60 support
   - OLPC battery: Add XO-1.5 and XO-1.75 support

  Misc Changes:
   - syscon-reboot: support mask property
   - AXP288 fuel gauge: Blacklist ACEPC T8/T11. Looks like some vendor
     thought it's a good idea to build a desktop system with a fuel
     gauge, that slowly "discharges"...
   - cpcap-battery: Fix calculation errors
   - misc fixes"

* tag 'for-v5.2' of git://git.kernel.org/pub/scm/linux/kernel/git/sre/linux-power-supply: (54 commits)
  power: supply: olpc_battery: force the le/be casts
  power: supply: ucs1002: Fix build error without CONFIG_REGULATOR
  power: supply: ucs1002: Fix wrong return value checking
  power: supply: Add driver for Microchip UCS1002
  dt-bindings: power: supply: Add bindings for Microchip UCS1002
  power: supply: core: Add POWER_SUPPLY_HEALTH_OVERCURRENT constant
  power: supply: core: fix clang -Wunsequenced
  power: supply: core: Add missing documentation for CHARGE_CONTROL_* properties
  power: supply: core: Add CHARGE_CONTROL_{START_THRESHOLD,END_THRESHOLD} properties
  power: supply: core: Add Standard, Adaptive, and Custom charge types
  power: supply: axp288_fuel_gauge: Add ACEPC T8 and T11 mini PCs to the blacklist
  power: supply: bq27xxx_battery: Notify also about status changes
  power: supply: olpc_battery: Have the framework register sysfs files for us
  power: supply: olpc_battery: Add OLPC XO 1.75 support
  power: supply: olpc_battery: Avoid using platform_info
  power: supply: olpc_battery: Use devm_power_supply_register()
  power: supply: olpc_battery: Move priv data to a struct
  power: supply: olpc_battery: Use DT to get battery version
  x86/platform/olpc: Use a correct version when making up a battery node
  x86/platform/olpc: Trivial code move in DT fixup
  ...
2019-05-15 18:50:40 -07:00
..
obsolete This feature/cleanup patchset includes the following patches: 2019-03-28 09:52:42 -07:00
removed acpi, nfit: Remove ecc_unit_size 2018-06-03 12:49:15 -07:00
stable Char/Misc patches for 5.2-rc1 - part 2 2019-05-07 13:39:22 -07:00
testing power supply and reset changes for the v5.2 series 2019-05-15 18:50:40 -07:00
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.