joystick.jl

# read from Raspbery Pi Sense HAT joystick

function _stick_input_dev()
    try
        for devname in readdir("/sys/class/input")
            sysfname = joinpath("/sys/class/input",devname,"device","name")
            if startswith(devname, "event") && isfile(sysfname)
                if startswith(readstring(sysfname),"Raspberry Pi Sense HAT Joystick")
                    return joinpath("/dev/input",devname)
                end
            end
        end
    catch e
    end
    error("Sense Hat not found.")
end

const STICK_INPUT_DEV = _stick_input_dev()


const EV_KEY = Cushort(0x01)

const KEY_UP    = Cushort(103)
const KEY_LEFT  = Cushort(105)
const KEY_RIGHT = Cushort(106)
const KEY_DOWN  = Cushort(108)
const KEY_ENTER = Cushort(28)

const STATE_RELEASE = Cint(0)
const STATE_PRESS   = Cint(1)
const STATE_HOLD    = Cint(2)


immutable Stick
    tv_sec::Clong
    tv_usec::Clong
    ev_type::Cushort
    ev_code::Cushort
    ev_value::Cuint
end

Base.read(io::IO, ::Type{Stick}) = read(io, Ref{Stick}())[]

@async begin
    dev = open(STICK_INPUT_DEV)
    while true
        s = read(dev, Stick)
        if s.ev_type == EV_KEY
            println(s)
        end
    end
end