[PATCH] RFC: name the Raspberry Pi GPIO lines

[Linus Walleij]

On Wed, Oct 19, 2016 at 6:07 PM, Eric Anholt <eric at anholt.net> wrote:

> But for debugging GPIO I want the debug to
> be fetching the actual state back out of the hardware, not relying on
> whatever we programmed last.  For example, the key to figuring out why
> my original FXL6408 GPIO expander driver didn't work was was seeing that
> the pinmux was changing a bunch, because the firmware was manipulating
> it.

GPIO supports the .get_direction() callback which is implemented in the
BCM2835 driver. It is called by the gpiolib at boot and some other times
(like debugfs view) to check the hardware direction.

We should implement something like .get_single_ended() to also read
out the open drain/source settings but I haven't gotten around to do
that.

Yours,
Linus Walleij