192 lines
7.3 KiB
ReStructuredText
192 lines
7.3 KiB
ReStructuredText
---------------------------
|
|
Linux Gamepad Specification
|
|
---------------------------
|
|
|
|
:Author: 2013 by David Herrmann <dh.herrmann@gmail.com>
|
|
|
|
|
|
Introduction
|
|
~~~~~~~~~~~~
|
|
Linux provides many different input drivers for gamepad hardware. To avoid
|
|
having user-space deal with different button-mappings for each gamepad, this
|
|
document defines how gamepads are supposed to report their data.
|
|
|
|
Geometry
|
|
~~~~~~~~
|
|
As "gamepad" we define devices which roughly look like this::
|
|
|
|
____________________________ __
|
|
/ [__ZL__] [__ZR__] \ |
|
|
/ [__ TL __] [__ TR __] \ | Front Triggers
|
|
__/________________________________\__ __|
|
|
/ _ \ |
|
|
/ /\ __ (N) \ |
|
|
/ || __ |MO| __ _ _ \ | Main Pad
|
|
| <===DP===> |SE| |ST| (W) -|- (E) | |
|
|
\ || ___ ___ _ / |
|
|
/\ \/ / \ / \ (S) /\ __|
|
|
/ \________ | LS | ____ | RS | ________/ \ |
|
|
| / \ \___/ / \ \___/ / \ | | Control Sticks
|
|
| / \_____/ \_____/ \ | __|
|
|
| / \ |
|
|
\_____/ \_____/
|
|
|
|
|________|______| |______|___________|
|
|
D-Pad Left Right Action Pad
|
|
Stick Stick
|
|
|
|
|_____________|
|
|
Menu Pad
|
|
|
|
Most gamepads have the following features:
|
|
|
|
- Action-Pad
|
|
4 buttons in diamonds-shape (on the right side). The buttons are
|
|
differently labeled on most devices so we define them as NORTH,
|
|
SOUTH, WEST and EAST.
|
|
- D-Pad (Direction-pad)
|
|
4 buttons (on the left side) that point up, down, left and right.
|
|
- Menu-Pad
|
|
Different constellations, but most-times 2 buttons: SELECT - START
|
|
Furthermore, many gamepads have a fancy branded button that is used as
|
|
special system-button. It often looks different to the other buttons and
|
|
is used to pop up system-menus or system-settings.
|
|
- Analog-Sticks
|
|
Analog-sticks provide freely moveable sticks to control directions. Not
|
|
all devices have both or any, but they are present at most times.
|
|
Analog-sticks may also provide a digital button if you press them.
|
|
- Triggers
|
|
Triggers are located on the upper-side of the pad in vertical direction.
|
|
Not all devices provide them, but the upper buttons are normally named
|
|
Left- and Right-Triggers, the lower buttons Z-Left and Z-Right.
|
|
- Rumble
|
|
Many devices provide force-feedback features. But are mostly just
|
|
simple rumble motors.
|
|
|
|
Detection
|
|
~~~~~~~~~
|
|
|
|
All gamepads that follow the protocol described here map BTN_GAMEPAD. This is
|
|
an alias for BTN_SOUTH/BTN_A. It can be used to identify a gamepad as such.
|
|
However, not all gamepads provide all features, so you need to test for all
|
|
features that you need, first. How each feature is mapped is described below.
|
|
|
|
Legacy drivers often don't comply to these rules. As we cannot change them
|
|
for backwards-compatibility reasons, you need to provide fixup mappings in
|
|
user-space yourself. Some of them might also provide module-options that
|
|
change the mappings so you can advise users to set these.
|
|
|
|
All new gamepads are supposed to comply with this mapping. Please report any
|
|
bugs, if they don't.
|
|
|
|
There are a lot of less-featured/less-powerful devices out there, which re-use
|
|
the buttons from this protocol. However, they try to do this in a compatible
|
|
fashion. For example, the "Nintendo Wii Nunchuk" provides two trigger buttons
|
|
and one analog stick. It reports them as if it were a gamepad with only one
|
|
analog stick and two trigger buttons on the right side.
|
|
But that means, that if you only support "real" gamepads, you must test
|
|
devices for _all_ reported events that you need. Otherwise, you will also get
|
|
devices that report a small subset of the events.
|
|
|
|
No other devices, that do not look/feel like a gamepad, shall report these
|
|
events.
|
|
|
|
Events
|
|
~~~~~~
|
|
|
|
Gamepads report the following events:
|
|
|
|
- Action-Pad:
|
|
|
|
Every gamepad device has at least 2 action buttons. This means, that every
|
|
device reports BTN_SOUTH (which BTN_GAMEPAD is an alias for). Regardless
|
|
of the labels on the buttons, the codes are sent according to the
|
|
physical position of the buttons.
|
|
|
|
Please note that 2- and 3-button pads are fairly rare and old. You might
|
|
want to filter gamepads that do not report all four.
|
|
|
|
- 2-Button Pad:
|
|
|
|
If only 2 action-buttons are present, they are reported as BTN_SOUTH and
|
|
BTN_EAST. For vertical layouts, the upper button is BTN_EAST. For
|
|
horizontal layouts, the button more on the right is BTN_EAST.
|
|
|
|
- 3-Button Pad:
|
|
|
|
If only 3 action-buttons are present, they are reported as (from left
|
|
to right): BTN_WEST, BTN_SOUTH, BTN_EAST
|
|
If the buttons are aligned perfectly vertically, they are reported as
|
|
(from top down): BTN_WEST, BTN_SOUTH, BTN_EAST
|
|
|
|
- 4-Button Pad:
|
|
|
|
If all 4 action-buttons are present, they can be aligned in two
|
|
different formations. If diamond-shaped, they are reported as BTN_NORTH,
|
|
BTN_WEST, BTN_SOUTH, BTN_EAST according to their physical location.
|
|
If rectangular-shaped, the upper-left button is BTN_NORTH, lower-left
|
|
is BTN_WEST, lower-right is BTN_SOUTH and upper-right is BTN_EAST.
|
|
|
|
- D-Pad:
|
|
|
|
Every gamepad provides a D-Pad with four directions: Up, Down, Left, Right
|
|
Some of these are available as digital buttons, some as analog buttons. Some
|
|
may even report both. The kernel does not convert between these so
|
|
applications should support both and choose what is more appropriate if
|
|
both are reported.
|
|
|
|
- Digital buttons are reported as:
|
|
|
|
BTN_DPAD_*
|
|
|
|
- Analog buttons are reported as:
|
|
|
|
ABS_HAT0X and ABS_HAT0Y
|
|
|
|
(for ABS values negative is left/up, positive is right/down)
|
|
|
|
- Analog-Sticks:
|
|
|
|
The left analog-stick is reported as ABS_X, ABS_Y. The right analog stick is
|
|
reported as ABS_RX, ABS_RY. Zero, one or two sticks may be present.
|
|
If analog-sticks provide digital buttons, they are mapped accordingly as
|
|
BTN_THUMBL (first/left) and BTN_THUMBR (second/right).
|
|
|
|
(for ABS values negative is left/up, positive is right/down)
|
|
|
|
- Triggers:
|
|
|
|
Trigger buttons can be available as digital or analog buttons or both. User-
|
|
space must correctly deal with any situation and choose the most appropriate
|
|
mode.
|
|
|
|
Upper trigger buttons are reported as BTN_TR or ABS_HAT1X (right) and BTN_TL
|
|
or ABS_HAT1Y (left). Lower trigger buttons are reported as BTN_TR2 or
|
|
ABS_HAT2X (right/ZR) and BTN_TL2 or ABS_HAT2Y (left/ZL).
|
|
|
|
If only one trigger-button combination is present (upper+lower), they are
|
|
reported as "right" triggers (BTN_TR/ABS_HAT1X).
|
|
|
|
(ABS trigger values start at 0, pressure is reported as positive values)
|
|
|
|
- Menu-Pad:
|
|
|
|
Menu buttons are always digital and are mapped according to their location
|
|
instead of their labels. That is:
|
|
|
|
- 1-button Pad:
|
|
|
|
Mapped as BTN_START
|
|
|
|
- 2-button Pad:
|
|
|
|
Left button mapped as BTN_SELECT, right button mapped as BTN_START
|
|
|
|
Many pads also have a third button which is branded or has a special symbol
|
|
and meaning. Such buttons are mapped as BTN_MODE. Examples are the Nintendo
|
|
"HOME" button, the XBox "X"-button or Sony "PS" button.
|
|
|
|
- Rumble:
|
|
|
|
Rumble is advertised as FF_RUMBLE.
|