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Input: rotary_encoder - add support for REL_* axes

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The rotary encoder driver only supports returning input events
for ABS_* axes, this adds support for REL_* axes.  The relative
axis input event is reported as -1 for each counter-clockwise
step and +1 for each clockwise step.

The ability to clamp the position of ABS_* axes between 0 and
a maximum of "steps" has also been added.

Signed-off-by: H Hartley Sweeten <hsweeten@visionengravers.com>
Signed-off-by: Daniel Mack <daniel@caiaq.de>
Signed-off-by: Dmitry Torokhov <dtor@mail.ru>
This commit is contained in:
H Hartley Sweeten
2009-04-17 20:12:35 -07:00
committed by Dmitry Torokhov
parent 3f3e7c6e13
commit bd3ce65560
3 changed files with 51 additions and 21 deletions
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9
Documentation/input/rotary-encoder.txt
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@@ -67,7 +67,12 @@ data with it.
struct rotary_encoder_platform_data is declared in
include/linux/rotary-encoder.h and needs to be filled with the number of
steps the encoder has and can carry information about externally inverted
signals (because of used invertig buffer or other reasons).
signals (because of an inverting buffer or other reasons). The encoder
can be set up to deliver input information as either an absolute or relative
axes. For relative axes the input event returns +/-1 for each step. For
absolute axes the position of the encoder can either roll over between zero
and the number of steps or will clamp at the maximum and zero depending on
the configuration.
Because GPIO to IRQ mapping is platform specific, this information must
be given in seperately to the driver. See the example below.
@@ -85,6 +90,8 @@ be given in seperately to the driver. See the example below.
static struct rotary_encoder_platform_data my_rotary_encoder_info = {
.steps = 24,
.axis = ABS_X,
.relative_axis = false,
.rollover = false,
.gpio_a = GPIO_ROTARY_A,
.gpio_b = GPIO_ROTARY_B,
.inverted_a = 0,