lua_userleds

Lua module wrapper for Nuttx userleds driver

This Lua module adds an ioctl() method to the file type and defines a table of ioctl commands for the Nuttx userleds driver.

usage

To start, open the /dev/userleds device:

> leds = io.open("/dev/userleds", "wb")

The ioctl() method accepts a variable number of arguments and returns a variable number of results, based on the ioctl command. The global table ioctls contains the following commands:

ioctls.ULEDIOC_SUPPORTED

Report the set of LEDs supported by the hardware. Returns an integer bitfield with bits set for supported LEDs.

> leds:ioctl(ioctls.ULEDIOC_SUPPORTED)
3 -- 0b11, two LEDs supported

ioctls.ULEDIOC_SETLED

Set the state of one LED. Accepts an integer for LED index and boolean for LED state.

-- turn 1st LED on
> leds:ioctl(ioctls.ULEDIOC_SETLED, 0, true)
> leds:ioctl(ioctls.ULEDIOC_SETLED, 0, 1)
> leds:ioctl(ioctls.ULEDIOC_SETLED, 0, 0) -- any numeric value is true in Lua!
-- turn 2nd LED off
> leds:ioctl(ioctls.ULEDIOC_SETLED, 1, false)
> leds:ioctl(ioctls.ULEDIOC_SETLED, 1, nil)

ioctls.ULEDIOC_SETALL

Set the state of all LEDs. Accepts an integer bitfield with bits set for on LEDs.

-- set 1st LED off and 2nd LED on
> leds:ioctl(ioctls.ULEDIOC_SETALL, 1 << 1)

ioctls.ULEDIOC_GETALL

Get the state of all LEDs. Returns an integer bitfield with bits set for on LEDs.

> leds:ioctl(ioctls.ULEDIOC_GETALL)
2 -- 0b10, 1st LED off and 2nd LED on