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authorLinus Torvalds <torvalds@linux-foundation.org>2017-05-03 12:38:20 -0700
committerLinus Torvalds <torvalds@linux-foundation.org>2017-05-03 12:38:20 -0700
commit16a12fa9aed176444fc795b09e796be41902bb08 (patch)
treebd158def3263a8b0d0f0886fd0fcd32728242dc4 /Documentation/input/notifier.rst
parentd25e436c4b68db2895185b24ad1f22499c2f87b0 (diff)
parent0337966d121ebebf73a1c346123e8112796e684e (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up introduction Input: docs - split input docs into kernel- and user-facing Input: docs - note that MT-A protocol is obsolete Input: docs - update joystick documentation a bit Input: docs - remove disclaimer/GPL notice Input: fix "Game console" heading level in joystick documentation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 ...
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+=================
+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,&params) == NOTIFY_STOP)
+ || !bound) {
+ notifier_call_chain(KBD_UNBOUND_KEYCODE,&params);
+ return;
+ }
+
+ if (unicode) {
+ param.value = unicode;
+ if (notifier_call_chain(KBD_UNICODE,&params) == NOTIFY_STOP)
+ return;
+ emit unicode;
+ return;
+ }
+
+ params.value = keysym;
+ if (notifier_call_chain(KBD_KEYSYM,&params) == NOTIFY_STOP)
+ return;
+ apply keysym;
+ notifier_call_chain(KBD_POST_KEYSYM,&params);
+ }
+
+.. note:: This notifier is usually called from interrupt context.