path: root/Documentation/input/rotary-encoder.txt
diff options
Diffstat (limited to 'Documentation/input/rotary-encoder.txt')
1 files changed, 8 insertions, 1 deletions
diff --git a/Documentation/input/rotary-encoder.txt b/Documentation/input/rotary-encoder.txt
index 435102a26d9..3a6aec40c0b 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,