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author | Linus Torvalds <torvalds@linux-foundation.org> | 2017-05-03 12:38:20 -0700 |
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committer | Linus Torvalds <torvalds@linux-foundation.org> | 2017-05-03 12:38:20 -0700 |
commit | 16a12fa9aed176444fc795b09e796be41902bb08 (patch) | |
tree | bd158def3263a8b0d0f0886fd0fcd32728242dc4 /Documentation/input/notifier.rst | |
parent | d25e436c4b68db2895185b24ad1f22499c2f87b0 (diff) | |
parent | 0337966d121ebebf73a1c346123e8112796e684e (diff) |
Merge branch 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/dtor/input
Pull input subsystem updates from Dmitry Torokhov:
- a big update from Mauro converting input documentation to ReST format
- Synaptics PS/2 is now aware of SMBus companion devices, which means
that we can now use native RMI4 protocol to handle touchpads, instead
of relying on legacy PS/2 mode.
- we removed support from BMA180 accelerometer from input devices as it
is now handled properly by IIO
- update to TSC2007 to corretcly report pressure
- other miscellaneous driver fixes.
* 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/dtor/input: (152 commits)
Input: ar1021_i2c - use BIT to check for a bit
Input: twl4030-pwrbutton - use input_set_capability() helper
Input: twl4030-pwrbutton - use correct device for irq request
Input: ar1021_i2c - enable touch mode during open
Input: add uinput documentation
dt-bindings: input: add bindings document for ar1021_i2c driver
dt-bindings: input: rotary-encoder: fix typo
Input: xen-kbdfront - add module parameter for setting resolution
ARM: pxa/raumfeld: fix compile error in rotary controller resources
Input: xpad - do not suggest writing to Dominic
Input: xpad - don't use literal blocks inside footnotes
Input: xpad - note that usb/devices is now at /sys/kernel/debug/
Input: docs - freshen up introduction
Input: docs - split input docs into kernel- and user-facing
Input: docs - note that MT-A protocol is obsolete
Input: docs - update joystick documentation a bit
Input: docs - remove disclaimer/GPL notice
Input: fix "Game console" heading level in joystick documentation
Input: rotary-encoder - remove references to platform data from docs
Input: move documentation for Amiga CD32
...
Diffstat (limited to 'Documentation/input/notifier.rst')
-rw-r--r-- | Documentation/input/notifier.rst | 54 |
1 files changed, 54 insertions, 0 deletions
diff --git a/Documentation/input/notifier.rst b/Documentation/input/notifier.rst new file mode 100644 index 000000000000..161350cb865e --- /dev/null +++ b/Documentation/input/notifier.rst @@ -0,0 +1,54 @@ +================= +Keyboard notifier +================= + +One can use register_keyboard_notifier to get called back on keyboard +events (see kbd_keycode() function for details). The passed structure is +keyboard_notifier_param: + +- 'vc' always provide the VC for which the keyboard event applies; +- 'down' is 1 for a key press event, 0 for a key release; +- 'shift' is the current modifier state, mask bit indexes are KG_*; +- 'value' depends on the type of event. + +- KBD_KEYCODE events are always sent before other events, value is the keycode. +- KBD_UNBOUND_KEYCODE events are sent if the keycode is not bound to a keysym. + value is the keycode. +- KBD_UNICODE events are sent if the keycode -> keysym translation produced a + unicode character. value is the unicode value. +- KBD_KEYSYM events are sent if the keycode -> keysym translation produced a + non-unicode character. value is the keysym. +- KBD_POST_KEYSYM events are sent after the treatment of non-unicode keysyms. + That permits one to inspect the resulting LEDs for instance. + +For each kind of event but the last, the callback may return NOTIFY_STOP in +order to "eat" the event: the notify loop is stopped and the keyboard event is +dropped. + +In a rough C snippet, we have:: + + kbd_keycode(keycode) { + ... + params.value = keycode; + if (notifier_call_chain(KBD_KEYCODE,¶ms) == NOTIFY_STOP) + || !bound) { + notifier_call_chain(KBD_UNBOUND_KEYCODE,¶ms); + return; + } + + if (unicode) { + param.value = unicode; + if (notifier_call_chain(KBD_UNICODE,¶ms) == NOTIFY_STOP) + return; + emit unicode; + return; + } + + params.value = keysym; + if (notifier_call_chain(KBD_KEYSYM,¶ms) == NOTIFY_STOP) + return; + apply keysym; + notifier_call_chain(KBD_POST_KEYSYM,¶ms); + } + +.. note:: This notifier is usually called from interrupt context. |