diff options
| -rw-r--r-- | Documentation/input/event-codes.txt | 72 |
1 files changed, 64 insertions, 8 deletions
diff --git a/Documentation/input/event-codes.txt b/Documentation/input/event-codes.txt index 23fcb05175b..53305bd0818 100644 --- a/Documentation/input/event-codes.txt +++ b/Documentation/input/event-codes.txt @@ -17,11 +17,11 @@ reports supported by a device are also provided by sysfs in class/input/event*/device/capabilities/, and the properties of a device are provided in class/input/event*/device/properties. -Types: -========== -Types are groupings of codes under a logical input construct. Each type has a -set of applicable codes to be used in generating events. See the Codes section -for details on valid codes for each type. +Event types: +=========== +Event types are groupings of codes under a logical input construct. Each +type has a set of applicable codes to be used in generating events. See the +Codes section for details on valid codes for each type. * EV_SYN: - Used as markers to separate events. Events may be separated in time or in @@ -63,9 +63,9 @@ for details on valid codes for each type. * EV_FF_STATUS: - Used to receive force feedback device status. -Codes: -========== -Codes define the precise type of event. +Event codes: +=========== +Event codes define the precise type of event. EV_SYN: ---------- @@ -220,6 +220,56 @@ EV_PWR: EV_PWR events are a special type of event used specifically for power mangement. Its usage is not well defined. To be addressed later. +Device properties: +================= +Normally, userspace sets up an input device based on the data it emits, +i.e., the event types. In the case of two devices emitting the same event +types, additional information can be provided in the form of device +properties. + +INPUT_PROP_DIRECT + INPUT_PROP_POINTER: +-------------------------------------- +The INPUT_PROP_DIRECT property indicates that device coordinates should be +directly mapped to screen coordinates (not taking into account trivial +transformations, such as scaling, flipping and rotating). Non-direct input +devices require non-trivial transformation, such as absolute to relative +transformation for touchpads. Typical direct input devices: touchscreens, +drawing tablets; non-direct devices: touchpads, mice. + +The INPUT_PROP_POINTER property indicates that the device is not transposed +on the screen and thus requires use of an on-screen pointer to trace user's +movements. Typical pointer devices: touchpads, tablets, mice; non-pointer +device: touchscreen. + +If neither INPUT_PROP_DIRECT or INPUT_PROP_POINTER are set, the property is +considered undefined and the device type should be deduced in the +traditional way, using emitted event types. + +INPUT_PROP_BUTTONPAD: +-------------------- +For touchpads where the button is placed beneath the surface, such that +pressing down on the pad causes a button click, this property should be +set. Common in clickpad notebooks and macbooks from 2009 and onwards. + +Originally, the buttonpad property was coded into the bcm5974 driver +version field under the name integrated button. For backwards +compatibility, both methods need to be checked in userspace. + +INPUT_PROP_SEMI_MT: +------------------ +Some touchpads, most common between 2008 and 2011, can detect the presence +of multiple contacts without resolving the individual positions; only the +number of contacts and a rectangular shape is known. For such +touchpads, the semi-mt property should be set. + +Depending on the device, the rectangle may enclose all touches, like a +bounding box, or just some of them, for instance the two most recent +touches. The diversity makes the rectangle of limited use, but some +gestures can normally be extracted from it. + +If INPUT_PROP_SEMI_MT is not set, the device is assumed to be a true MT +device. + Guidelines: ========== The guidelines below ensure proper single-touch and multi-finger functionality. @@ -240,6 +290,8 @@ used to report when a touch is active on the screen. BTN_{MOUSE,LEFT,MIDDLE,RIGHT} must not be reported as the result of touch contact. BTN_TOOL_<name> events should be reported where possible. +For new hardware, INPUT_PROP_DIRECT should be set. + Trackpads: ---------- Legacy trackpads that only provide relative position information must report @@ -250,6 +302,8 @@ location of the touch. BTN_TOUCH should be used to report when a touch is active on the trackpad. Where multi-finger support is available, BTN_TOOL_<name> should be used to report the number of touches active on the trackpad. +For new hardware, INPUT_PROP_POINTER should be set. + Tablets: ---------- BTN_TOOL_<name> events must be reported when a stylus or other tool is active on @@ -260,3 +314,5 @@ button may be used for buttons on the tablet except BTN_{MOUSE,LEFT}. BTN_{0,1,2,etc} are good generic codes for unlabeled buttons. Do not use meaningful buttons, like BTN_FORWARD, unless the button is labeled for that purpose on the device. + +For new hardware, both INPUT_PROP_DIRECT and INPUT_PROP_POINTER should be set. |