sysfsGpio - Open Drain en Tri State API have not been implemented

[annaertd]

I created a sample application for the WP8548 on my mangOH green rev 8 board which controls some LEDs via een external pullup resistor. For electronic safety reasons I prefer to use external pullup resistors with my output pins iso internal pullups.
Then I need to control the outputs with open drain functionality.
During build time everything ran smoothly, but, at runtime I discovered that the API functions below have not been implemented.

What is the reason behind this?
Is it possible to add this functionality?

gpioSysfs_SetOpenDrain
gpioSysfs_SetTriState
gpioSysfs_SetHighZ

[CoRfr]

Hi @annaertd,

I think they have not been implemented because the chip on WP85 doesn't support them. So the APIs are present to be future proof but in the meantime :/
I would think you can emulate this as explained on the Linux doc: http://elixir.free-electrons.com/linux/v3.3/source/Documentation/gpio.txt

Some GPIO controllers directly support open drain outputs; many don't. When
you need open drain signaling but your hardware doesn't directly support it,
there's a common idiom you can use to emulate it with any GPIO pin that can
be used as either an input or an output:

LOW: gpio_direction_output(gpio, 0) ... this drives the signal
and overrides the pullup.

HIGH: gpio_direction_input(gpio) ... this turns off the output,
so the pullup (or some other device) controls the signal.

So if you use _SetInput it seems you can workaround that.