Using Pull-up resistors on gpio-pca953x expander

[Adam Ford]

The pca953x can support pull-up resistors, and I have a pcal6416 that
I'd like to enable them.

Ideally, I was hoping there would be a way to add enable to the device
tree, because the expander is connected to some buttons which are
grounded when pressed.  Without pull-up resistors enabled, the buttons
always appear to be pressed.

Is there some way to enable them?  I see the functionality is
available and called through gc->set_config = pca953x_gpio_set_config;

I don't know enough about the API to know how to enable this.  Can
someone give me some pointers?

Would you entertain my adding some device tree hooks to enable them?

adam