The devicetree binding for gpio-keys-polled already allows specifying what type of events (key / rel / abs) a button generates when pressed. But for rel / abs axis we also need to specify which value this specific gpio represents. One usecase is digital joysticks / direction-pads which are hooked up to gpio, in this case we've left and right buttons which we want to map to EV_ABS, ABS_X and we want generate events for left with a value of -1 and for right with a value of +1 (and similar for up / down and ABS_Y). Signed-off-by: Hans de Goede <hdegoede@xxxxxxxxxx> Acked-by: Rob Herring <robh@xxxxxxxxxx> --- Changes in v2: -Add Rob's ack -s/send/sent/ -Make the remarks of axis reporting a value of 0 when all buttons tied to that axis are released also apply to EV_REL axis Changes in v3: -Document that linux,input-value is a *signed* 32 bit variable and an example how to specify a negative value --- Documentation/devicetree/bindings/input/gpio-keys-polled.txt | 9 ++++++++- 1 file changed, 8 insertions(+), 1 deletion(-) diff --git a/Documentation/devicetree/bindings/input/gpio-keys-polled.txt b/Documentation/devicetree/bindings/input/gpio-keys-polled.txt index 5b91f5a..97e2467 100644 --- a/Documentation/devicetree/bindings/input/gpio-keys-polled.txt +++ b/Documentation/devicetree/bindings/input/gpio-keys-polled.txt @@ -13,11 +13,18 @@ Subnode properties: - gpios: OF device-tree gpio specification. - label: Descriptive name of the key. - - linux,code: Keycode to emit. + - linux,code: Key / Axis code to emit. Optional subnode-properties: - linux,input-type: Specify event type this button/key generates. If not specified defaults to <1> == EV_KEY. + - linux,input-value: If linux,input-type is EV_ABS or EV_REL then this + value is sent for events this button generates when pressed. + EV_ABS/EV_REL axis will generate an event with a value of 0 when + all buttons with linux,input-type == type and linux,code == axis + are released. This value is interpreted as a signed 32 bit value, + e.g. to make a button generate a value of -1 use: + linux,input-value = <0xffffffff>; /* -1 */ - debounce-interval: Debouncing interval time in milliseconds. If not specified defaults to 5. - wakeup-source: Boolean, button can wake-up the system. -- 2.4.3 -- To unsubscribe from this list: send the line "unsubscribe devicetree" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
