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linux-next/Documentation/devicetree/bindings/input/rotary-encoder.txt
Uwe Kleine-König 7dde4e7474 Input: rotary-encoder - support more than 2 gpios as input
This changes how the used gpios are stored (i.e. a struct gpio_descs
instead of two struct gpio_desc) and as with >2 gpios the states are
numbered differently the function rotary_encoder_get_state returns
unencoded numbers instead of grey encoded numbers before. The latter has
some implications on how the returned value is used and so the change is
bigger than one might expect at first.

Signed-off-by: Uwe Kleine-König <u.kleine-koenig@pengutronix.de>
Acked-by: Rob Herring <robh@kernel.org>
Acked-by: Daniel Mack <daniel@zonque.org>
Signed-off-by: Dmitry Torokhov <dmitry.torokhov@gmail.com>
2016-03-02 15:48:05 -08:00

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Rotary encoder DT bindings
Required properties:
- gpios: a spec for at least two GPIOs to be used, most significant first
Optional properties:
- linux,axis: the input subsystem axis to map to this rotary encoder.
Defaults to 0 (ABS_X / REL_X)
- rotary-encoder,steps: Number of steps in a full turnaround of the
encoder. Only relevant for absolute axis. Defaults to 24 which is a
typical value for such devices.
- rotary-encoder,relative-axis: register a relative axis rather than an
absolute one. Relative axis will only generate +1/-1 events on the input
device, hence no steps need to be passed.
- rotary-encoder,rollover: Automatic rollove when the rotary value becomes
greater than the specified steps or smaller than 0. For absolute axis only.
- rotary-encoder,steps-per-period: Number of steps (stable states) per period.
The values have the following meaning:
1: Full-period mode (default)
2: Half-period mode
4: Quarter-period mode
- wakeup-source: Boolean, rotary encoder can wake up the system.
Deprecated properties:
- rotary-encoder,half-period: Makes the driver work on half-period mode.
This property is deprecated. Instead, a 'steps-per-period ' value should
be used, such as "rotary-encoder,steps-per-period = <2>".
See Documentation/input/rotary-encoder.txt for more information.
Example:
rotary@0 {
compatible = "rotary-encoder";
gpios = <&gpio 19 1>, <&gpio 20 0>; /* GPIO19 is inverted */
linux,axis = <0>; /* REL_X */
rotary-encoder,relative-axis;
};
rotary@1 {
compatible = "rotary-encoder";
gpios = <&gpio 21 0>, <&gpio 22 0>;
linux,axis = <1>; /* ABS_Y */
rotary-encoder,steps = <24>;
rotary-encoder,rollover;
};