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| author | H Hartley Sweeten <hartleys@visionengravers.com> | 2009-04-18 05:12:35 +0200 |
|---|---|---|
| committer | Dmitry Torokhov <dmitry.torokhov@gmail.com> | 2009-04-18 05:37:21 +0200 |
| commit | bd3ce6556072bdc8ea66dfd5448e184f189bdc7f (patch) | |
| tree | 264a0272647abe0ae4a7093abb3d6afc9b0a1bd2 /Documentation | |
| parent | Input: ads7846 - fix unsafe disable_irq (diff) | |
| download | linux-bd3ce6556072bdc8ea66dfd5448e184f189bdc7f.tar.xz linux-bd3ce6556072bdc8ea66dfd5448e184f189bdc7f.zip | |
Input: rotary_encoder - add support for REL_* axes
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>
Diffstat (limited to 'Documentation')
| -rw-r--r-- | Documentation/input/rotary-encoder.txt | 9 |
1 files changed, 8 insertions, 1 deletions
diff --git a/Documentation/input/rotary-encoder.txt b/Documentation/input/rotary-encoder.txt index 435102a26d96..3a6aec40c0b0 100644 --- a/Documentation/input/rotary-encoder.txt +++ b/Documentation/input/rotary-encoder.txt @@ -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, |