linux/Documentation/ABI
Greg Kroah-Hartman 4463c3e72d First round of new device support, features and cleanups for IIO in the 4.11 cycle.
It's shaping to be another fairly busy cycle. Lots more on the way!
 
 New device support
 * ads7950
   - new driver supporting ads7950, ads7951, ads7952, ads7953, ads7954,
   ads7955, ads7956, ads7957, ads7958, ads7959, ads7960, and ads7961 ADCs.
 * cm3605
   - New driver for this light sensor and proximity sensor  which is an
   analog part with some additional digital controls.
 * hx711
   - New driver.
 
 Core new stuff
 * Gravity sensor type.  This is a processed datastream in which the device
 will try to work out which way is down.
 * Split the buffer.h file into two parts. One provides the interface to 'use'
 a buffer, the second provides the internals of the buffer functionality as
 needed by implementations of buffers.
   - Move documentation inline so as to allow use of private: tag when
   generating documentation.
   - Add some utility functions for the few things that are directly done
   with the buffers.
   - Stop exporting functions that no-one uses outside of the core code.
   - Push docs down by the code in the c file where they should have always
   been.
   - Fix typo in kernel-doc for buffer.
   - push down some includes that were previously happening implicitly.
   - stop enabling the timestamp of the dummy device.
 
 Features and cleanups
 * ad5592r
   - ACPI support
 * ad5593r
   -ACPI support.
 * ad5933
   - Fix a false comment about size of a particular register.
 * ad7150
   - replace S_IRUGO | S_IWUSR with 0644.  I'm not that keen on these patches
   in general, but as it was nicely presented I took this one anyway. As a
   general rule will only take these as part of a larger driver cleanup.
   - don't eat an error but rather reutnr it in the write_event_config callback.
 * ad7606
   - replace non standard range attibute with _scale
 * ade7753
   - use usleep_range for short sleeps
 * ade7754
   - use usleep_range for short sleeps
 * ade7758
   - use usleep_range for short sleeps
 * ade7759
   - use usleep_range for short sleeps
 * ade7854
   - use usleep_range for short sleeps
 * adis16201
   - fix description
 * adis16203
   - fix description
   - fix copyright year
 * adis16209
   - fix description
 * adt7316
   - Add braces to arms of if else statement (for consistency)
   - Alignment fixes.
 * axp288
   - Fix up an issue with accidental overwrites of data.
 * bmi160
   - add deivce tables for i2c and spi to support correctly identifying the
   full dt name (including manufacturer).
   - device tree binding.
 * bmp280
   - use usleep_range for short sleeps.
 * cm3232
   - return error from cm3232_reg_init rather than eating it if the last write
   fails.
 * dummy driver
   - remove a semicolor found at end of a function defintition.
 * exynos-adc
   - use usleep_range for short sleeps.
 * hid-sensor (accel)
   - Add timestamp support.  The hardware can provide timestamps so lets support
   them. If not fall back to timestamps estimated in kernel.
 * hid-sensor (light)
   - Add a duplicate ID for the light channels so as to keep existing interface
   whilst also using the more standard IIO interface.
 * hts221
   - acpi probing
 * imx25-gcq
   - Add a macro call to allow this driver to be automatically loaded.
 * isl29028
   - reorganise code to avoid deep nesting of if statements.
   - move chip test and default regs into a function suitable or sharing with
   power management code.
   - tidy up some code alignment.
 * lidar-lite-v3
   - introduce compatible strings that make it clear Garmin have consideral
   friends.
 * mma8452
   - avoid returning signed value when unsigned is appropriate
 * spmi-vadc
   - Update function for generic voltage conversion to take into account that
   different channels on this device should be handled differently.
   - Rework code to allow per channel voltage scaling and support the standard
   options for this hardware.
   - Fixup three minor issues with the above patches for this part. These all
   effect test builds rather than the native builds for the part, but good to
   clean them up anyway.
 * st_sensors
   - support device matching from the ACPI DST tables.
   - acpi based probing for accelerometers
   - acpi based probing for pressure sensors
   - Allow pressure sensors to read negative values.
   - Export sampling frequency for lps25h and lps331ap.
   - Add support for the old DT bindings from the period when these deivces
   were often supported through windows.
 
 Docs fixup:
 * typo in sysfs-bus-iio
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Merge tag 'iio-for-4.11a' of git://git.kernel.org/pub/scm/linux/kernel/git/jic23/iio into staging-next

Jonathan writes:

First round of new device support, features and cleanups for IIO in the 4.11 cycle.

It's shaping to be another fairly busy cycle. Lots more on the way!

New device support
* ads7950
  - new driver supporting ads7950, ads7951, ads7952, ads7953, ads7954,
  ads7955, ads7956, ads7957, ads7958, ads7959, ads7960, and ads7961 ADCs.
* cm3605
  - New driver for this light sensor and proximity sensor  which is an
  analog part with some additional digital controls.
* hx711
  - New driver.

Core new stuff
* Gravity sensor type.  This is a processed datastream in which the device
will try to work out which way is down.
* Split the buffer.h file into two parts. One provides the interface to 'use'
a buffer, the second provides the internals of the buffer functionality as
needed by implementations of buffers.
  - Move documentation inline so as to allow use of private: tag when
  generating documentation.
  - Add some utility functions for the few things that are directly done
  with the buffers.
  - Stop exporting functions that no-one uses outside of the core code.
  - Push docs down by the code in the c file where they should have always
  been.
  - Fix typo in kernel-doc for buffer.
  - push down some includes that were previously happening implicitly.
  - stop enabling the timestamp of the dummy device.

Features and cleanups
* ad5592r
  - ACPI support
* ad5593r
  -ACPI support.
* ad5933
  - Fix a false comment about size of a particular register.
* ad7150
  - replace S_IRUGO | S_IWUSR with 0644.  I'm not that keen on these patches
  in general, but as it was nicely presented I took this one anyway. As a
  general rule will only take these as part of a larger driver cleanup.
  - don't eat an error but rather reutnr it in the write_event_config callback.
* ad7606
  - replace non standard range attibute with _scale
* ade7753
  - use usleep_range for short sleeps
* ade7754
  - use usleep_range for short sleeps
* ade7758
  - use usleep_range for short sleeps
* ade7759
  - use usleep_range for short sleeps
* ade7854
  - use usleep_range for short sleeps
* adis16201
  - fix description
* adis16203
  - fix description
  - fix copyright year
* adis16209
  - fix description
* adt7316
  - Add braces to arms of if else statement (for consistency)
  - Alignment fixes.
* axp288
  - Fix up an issue with accidental overwrites of data.
* bmi160
  - add deivce tables for i2c and spi to support correctly identifying the
  full dt name (including manufacturer).
  - device tree binding.
* bmp280
  - use usleep_range for short sleeps.
* cm3232
  - return error from cm3232_reg_init rather than eating it if the last write
  fails.
* dummy driver
  - remove a semicolor found at end of a function defintition.
* exynos-adc
  - use usleep_range for short sleeps.
* hid-sensor (accel)
  - Add timestamp support.  The hardware can provide timestamps so lets support
  them. If not fall back to timestamps estimated in kernel.
* hid-sensor (light)
  - Add a duplicate ID for the light channels so as to keep existing interface
  whilst also using the more standard IIO interface.
* hts221
  - acpi probing
* imx25-gcq
  - Add a macro call to allow this driver to be automatically loaded.
* isl29028
  - reorganise code to avoid deep nesting of if statements.
  - move chip test and default regs into a function suitable or sharing with
  power management code.
  - tidy up some code alignment.
* lidar-lite-v3
  - introduce compatible strings that make it clear Garmin have consideral
  friends.
* mma8452
  - avoid returning signed value when unsigned is appropriate
* spmi-vadc
  - Update function for generic voltage conversion to take into account that
  different channels on this device should be handled differently.
  - Rework code to allow per channel voltage scaling and support the standard
  options for this hardware.
  - Fixup three minor issues with the above patches for this part. These all
  effect test builds rather than the native builds for the part, but good to
  clean them up anyway.
* st_sensors
  - support device matching from the ACPI DST tables.
  - acpi based probing for accelerometers
  - acpi based probing for pressure sensors
  - Allow pressure sensors to read negative values.
  - Export sampling frequency for lps25h and lps331ap.
  - Add support for the old DT bindings from the period when these deivces
  were often supported through windows.

Docs fixup:
* typo in sysfs-bus-iio
2017-01-19 10:40:44 +01:00
..
obsolete Documentation: fix common spelling mistakes 2016-04-28 07:51:59 -06:00
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 First round of new device support, features and cleanups for IIO in the 4.11 cycle. 2017-01-19 10:40:44 +01:00
README docs: fix locations of several documents that got moved 2016-10-24 08:12:35 -02:00

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.