Tock capsule periodic accelerometer reading

accelerate.rs

use kernel::hil::time::{self, Alarm, Frequency};
use kernel::hil::sensors::{NineDof, NineDofClient};

pub struct Accelerate<'a, A: Alarm + 'a> {
    alarm: &'a A,
    ninedof: &'a NineDof
}

impl<'a, A: Alarm> Accelerate<'a, A> {
    pub fn new(alarm: &'a A, ninedof: &'a NineDof) -> Accelerate<'a, A> {
        Accelerate {
            alarm: alarm,
            ninedof: ninedof,
        }
    }

    pub fn start(&self) {
        self.alarm.set_alarm(
            self.alarm.now().wrapping_add(<A::Frequency>::frequency()))
    }
}

impl<'a, A: Alarm> time::Client for Accelerate<'a, A> {
    fn fired(&self) {
        self.ninedof.read_accelerometer();
    }
}

impl<'a, A: Alarm> NineDofClient for Accelerate<'a, A> {
    fn callback(&self, x: usize, y: usize, z: usize) {
        debug!("{} {} {}", x, y, z);
        self.start();
    }
}

boot_sequence.rs

    let accelerate_virtual_alarm = static_init!(
        VirtualMuxAlarm<'static, sam4l::ast::Ast>,
        VirtualMuxAlarm::new(mux_alarm));
    let accelerate = static_init!(
            capsules::accelerate::Accelerate<'static,
                                VirtualMuxAlarm<'static, sam4l::ast::Ast<'static>>>,
            capsules::accelerate::Accelerate::new(accelerate_virtual_alarm, fxos8700));
    accelerate_virtual_alarm.set_client(accelerate);
    {
        use kernel::hil::sensors::NineDof;
        fxos8700.set_client(accelerate);
    }
    accelerate.start();