Module capsules::button [−] [src]

Provides userspace control of buttons on a board.

This allows for much more cross platform controlling of buttons without having to know which of the GPIO pins exposed across the syscall interface are buttons.

Usage

let button_pins = static_init!(
    [&'static sam4l::gpio::GPIOPin; 1],
    [&sam4l::gpio::PA[16]]);
let button = static_init!(
    capsules::button::Button<'static, sam4l::gpio::GPIOPin>,
    capsules::button::Button::new(button_pins, kernel::Grant::create()));
for btn in button_pins.iter() {
    btn.set_client(button);
}

Syscall Interface

Stability: 2 - Stable

Command

Enable or disable button interrupts and read the current button state.

`command_num`

0: Driver check and get number of buttons on the board.
1: Enable interrupts for a given button. This will enable both press and depress events.
2: Disable interrupts for a button. No affect or reliance on registered callback.
3: Read the current state of the button.

Setup a callback for button presses.

`subscribe_num`

0: Set callback for pin interrupts. Note setting this callback has no reliance on individual pins being configured as interrupts. The interrupt will be called with two parameters: the index of the button that triggered the interrupt and the pressed (1) or not pressed (0) state of the button.

Reexports

use core::cell::Cell;

use kernel::AppId;

use kernel::Callback;

use kernel::Driver;

use kernel::Grant;

use kernel::ReturnCode;

use kernel::hil;

use kernel::hil::gpio::Client;

use kernel::hil::gpio::InterruptMode;

Structs

Button

Manages the list of GPIO pins that are connected to buttons and which apps are listening for interrupts from which buttons.

Enums

ButtonState	Values that are passed to userspace to identify if the button is pressed or not.
GpioMode	Whether the GPIOs for the buttons on this platform are low when the button is pressed or high.

This capsule keeps track for each app of which buttons it has a registered interrupt for. SubscribeMap is a bit array where bits are set to one if that app has an interrupt registered for that button.