The led driver provides generic support for handling LEDs, lamps and other annunciators.
The hardware driver must supply a function to turn the annunciator on and off and the device name of the annunciator relative to /dev/led/. The priv argument is passed back to this on/off function and can be used however the hardware driver sees fit.
The lamp can be controlled by opening and writing ASCII strings to the /dev/led/bla device.
In the following, we will use this special notation to indicate the resulting output of the annunciator: