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 Martínez <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>

1 files changed, 10 insertions, 1 deletions

diff --git a/Documentation/devicetree/bindings/input/rotary-encoder.txt b/Documentation/devicetree/bindings/input/rotary-encoder.txt
index 891ddba2d792..de99cbbbf6da 100644
--- a/Documentation/devicetree/bindings/input/rotary-encoder.txt
+++ b/Documentation/devicetree/bindings/input/rotary-encoder.txt
@@ -14,9 +14,18 @@ Optional properties:
   device, hence no steps need to be passed.
 - rotary-encoder,rollover: Automatic rollove when the rotary value becomes
   greater than the specified steps or smaller than 0. For absolute axis only.
-- rotary-encoder,half-period: Makes the driver work on half-period mode.
+- rotary-encoder,steps-per-period: Number of steps (stable states) per period.
+  The values have the following meaning:
+  1: Full-period mode (default)
+  2: Half-period mode
+  4: Quarter-period mode
 - wakeup-source: Boolean, rotary encoder can wake up the system.
 
+Deprecated properties:
+- rotary-encoder,half-period: Makes the driver work on half-period mode.
+  This property is deprecated. Instead, a 'steps-per-period ' value should
+  be used, such as "rotary-encoder,steps-per-period = <2>".
+
 See Documentation/input/rotary-encoder.txt for more information.
 
 Example: