Some rotary-encoder devices (such as those with detents) are capable of producing a stable event on each step. This simple patch adds support for this case, by implementing a new interruption handler. The handler needs only detect the direction of the turn and generate an event according to this detection. We encode the previous and the current state, and then use the sum of them to decide on the direction of the turn, according to the following simple table: Previous state + currrent state | Movement ========================================== 0b1101 | clockwise 0b0100 | .. 0b0010 | .. 0b1011 | .. ========================================== 0b1110 | counter-clockwise 0b0111 | .. 0b0001 | .. 0b1000 | .. (The other sumed values are considered illegal) This calculation is based on some previous work found at this blog: http://bildr.org/2012/08/rotary-encoder-arduino/ The result is a seemingly very robust behavior, with a truly simple implementation, that produces an event on each turn of the device. I don't have much experience with this rotary-encoder devices, so I'm sending this just as an RFC/PATCH, to get some early feedback. In particular, I got a bit puzzled by the current implementation with 'armed' and 'dis-armed'. Maybe there's some way of using the current driver and get an event on each turn? If this change looks more or less acceptable, I can add device-tree bindings (which are missing from this first patch) and re-send. Thanks! Ezequiel Garcia (1): Input: rotary-encoder: Add 'stepped' irq handler drivers/input/misc/rotary_encoder.c | 34 ++++++++++++++++++++++++++++++++++ include/linux/rotary_encoder.h | 1 + 2 files changed, 35 insertions(+) -- 1.8.1.5 -- To unsubscribe from this list: send the line "unsubscribe linux-input" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
