input/devices/rotary-encoder.rst

2 rotary-encoder - a generic driver for GPIO connected devices
8 --------
10 Rotary encoders are devices which are connected to the CPU or other
11 peripherals with two wires. The outputs are phase-shifted by 90 degrees
16 a stable state with both outputs high (half-period mode) and some have
17 a stable state in all steps (quarter-period mode).
33                 |<-------->|
36                 |<-->|
37 	          one step (half-period mode)
40 	          one step (quarter-period mode)
47 ----------------------
49 In half-period mode, state a) and c) above are used to determine the
52 (i.e. the rotation was not reversed half-way).
60 	When entering this state, the encoder is put into 'armed' state,
61 	meaning that there it has seen half the way of a one-step transition.
64 	This state is used to recognize a counter-clockwise turn
67 	Parking position. If the encoder enters this state, a full transition
72 ---------------------
80 -----------------
83 name 'rotary-encoder' and associate the IRQs and some specific platform
100 		.dev_id = "rotary-encoder.0",
102 			GPIO_LOOKUP_IDX("gpio-0",
104 			GPIO_LOOKUP_IDX("gpio-0",
111 		PROPERTY_ENTRY_U32("rotary-encoder,steps-per-period", 24),
113 		PROPERTY_ENTRY_U32("rotary-encoder,relative_axis",    0),
122 		.name		= "rotary-encoder",