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| author | Ezequiel Garcia <ezequiel@vanguardiasur.com.ar> | 2015-10-13 23:39:50 -0700 |
|---|---|---|
| committer | Dmitry Torokhov <dmitry.torokhov@gmail.com> | 2015-10-16 15:32:18 -0700 |
| commit | 3a341a4c30d427fd05617087db1564a595f65093 (patch) | |
| tree | 84898e187b5128e1e51e9f5ed41114176181b71e /Documentation/input | |
| parent | 648b15cb79e90d80f7b53d0184bdb14132a03754 (diff) | |
| download | linux-3a341a4c30d427fd05617087db1564a595f65093.tar.bz2 | |
Input: rotary-encoder - add support for quarter-period mode
Some encoders have both outputs low in stable states, others also have
a stable state with both outputs high (half-period mode) and some have
a stable state in all steps (quarter-period mode). The driver used to
support the former states and with this change it can also support the
later.
This commit also deprecates the 'half-period' property and introduces
a new property 'steps-per-period'. This property specifies the
number of steps (stable states) produced by the rotary encoder
for each GPIO period.
Signed-off-by: Guido MartÃnez <guido@vanguardiasur.com.ar>
Signed-off-by: Ezequiel Garcia <ezequiel@vanguardiasur.com.ar>
Acked-by: Rob Herring <robh@kernel.org>
Signed-off-by: Dmitry Torokhov <dmitry.torokhov@gmail.com>
Diffstat (limited to 'Documentation/input')
| -rw-r--r-- | Documentation/input/rotary-encoder.txt | 8 |
1 files changed, 6 insertions, 2 deletions
diff --git a/Documentation/input/rotary-encoder.txt b/Documentation/input/rotary-encoder.txt index bddbee188624..46a74f0c551a 100644 --- a/Documentation/input/rotary-encoder.txt +++ b/Documentation/input/rotary-encoder.txt @@ -9,8 +9,9 @@ peripherals with two wires. The outputs are phase-shifted by 90 degrees and by triggering on falling and rising edges, the turn direction can be determined. -Some encoders have both outputs low in stable states, whereas others also have -a stable state with both outputs high (half-period mode). +Some encoders have both outputs low in stable states, others also have +a stable state with both outputs high (half-period mode) and some have +a stable state in all steps (quarter-period mode). The phase diagram of these two outputs look like this: @@ -32,6 +33,9 @@ The phase diagram of these two outputs look like this: |<-->| one step (half-period mode) + |<>| + one step (quarter-period mode) + For more information, please see https://en.wikipedia.org/wiki/Rotary_encoder |