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authorH Hartley Sweeten <hartleys@visionengravers.com>2009-04-17 23:12:35 -0400
committerDmitry Torokhov <dmitry.torokhov@gmail.com>2009-04-17 23:37:21 -0400
commitbd3ce6556072bdc8ea66dfd5448e184f189bdc7f (patch)
tree264a0272647abe0ae4a7093abb3d6afc9b0a1bd2 /Documentation
parent3f3e7c6e139f704e2f48ea3b45ff7724a8d46456 (diff)
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.txt9
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.
67struct rotary_encoder_platform_data is declared in 67struct rotary_encoder_platform_data is declared in
68include/linux/rotary-encoder.h and needs to be filled with the number of 68include/linux/rotary-encoder.h and needs to be filled with the number of
69steps the encoder has and can carry information about externally inverted 69steps the encoder has and can carry information about externally inverted
70signals (because of used invertig buffer or other reasons). 70signals (because of an inverting buffer or other reasons). The encoder
71can be set up to deliver input information as either an absolute or relative
72axes. For relative axes the input event returns +/-1 for each step. For
73absolute axes the position of the encoder can either roll over between zero
74and the number of steps or will clamp at the maximum and zero depending on
75the configuration.
71 76
72Because GPIO to IRQ mapping is platform specific, this information must 77Because GPIO to IRQ mapping is platform specific, this information must
73be given in seperately to the driver. See the example below. 78be 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.
85static struct rotary_encoder_platform_data my_rotary_encoder_info = { 90static struct rotary_encoder_platform_data my_rotary_encoder_info = {
86 .steps = 24, 91 .steps = 24,
87 .axis = ABS_X, 92 .axis = ABS_X,
93 .relative_axis = false,
94 .rollover = false,
88 .gpio_a = GPIO_ROTARY_A, 95 .gpio_a = GPIO_ROTARY_A,
89 .gpio_b = GPIO_ROTARY_B, 96 .gpio_b = GPIO_ROTARY_B,
90 .inverted_a = 0, 97 .inverted_a = 0,