Merge branches 'core-fixes-for-linus' and 'irq-fixes-for-linus' of git://git.kernel...

[pandora-kernel.git] / Documentation / input / rotary-encoder.txt

diff --git a/Documentation/input/rotary-encoder.txt b/Documentation/input/rotary-encoder.txt
index 943e8f6..92e68bc 100644 (file)
--- a/Documentation/input/rotary-encoder.txt
+++ b/Documentation/input/rotary-encoder.txt
@@ -9,6 +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.
 
 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).
+

 The phase diagram of these two outputs look like this:
 
                   _____       _____       _____
 The phase diagram of these two outputs look like this:
 
                   _____       _____       _____


@@ -26,6 +29,8 @@ The phase diagram of these two outputs look like this:
                 |<-------->|
                  one step
 
                 |<-------->|
                  one step
 

+                |<-->|
+                 one step (half-period mode)

 
 For more information, please see
        http://en.wikipedia.org/wiki/Rotary_encoder
 
 For more information, please see
        http://en.wikipedia.org/wiki/Rotary_encoder


@@ -34,6 +39,13 @@ For more information, please see
 1. Events / state machine
 -------------------------
 
 1. Events / state machine
 -------------------------
 

+In half-period mode, state a) and c) above are used to determine the
+rotational direction based on the last stable state. Events are reported in
+states b) and d) given that the new stable state is different from the last
+(i.e. the rotation was not reversed half-way).
+
+Otherwise, the following apply:
+

 a) Rising edge on channel A, channel B in low state
        This state is used to recognize a clockwise turn
 
 a) Rising edge on channel A, channel B in low state
        This state is used to recognize a clockwise turn
 


@@ -96,6 +108,7 @@ static struct rotary_encoder_platform_data my_rotary_encoder_info = {
        .gpio_b         = GPIO_ROTARY_B,
        .inverted_a     = 0,
        .inverted_b     = 0,
        .gpio_b         = GPIO_ROTARY_B,
        .inverted_a     = 0,
        .inverted_b     = 0,

+       .half_period    = false,

 };
 
 static struct platform_device rotary_encoder_device = {
 };
 
 static struct platform_device rotary_encoder_device = {