Re: [RFC] gpio: expose pull-up/pull-down line flags to userspace

[Kent Gibson <warthog618@xxxxxxxxx>]

On Fri, Oct 11, 2019 at 03:06:41PM +0200, Drew Fustini wrote:
> Hi Kent,
> 
> I noticed there are some additional commits in your branch including:
> 7f0bcb88f583  pull up/down on output is actually a valid option
> 
Yeah pulls make no sense for push pull lines, but while looking into
disabling bias I discovered that there are some chips that support
pull-up/down for open drain/source outputs.
It seemed reasonable to support them rather than reject them outright,
hence the reversal.

> Do you know what the result would be when the line is an output?
> 
Behaviour would depend on the driver and chip.
I'm assuming the user would only request combinations that make sense
and that the driver would reject any combinations that might have
unfortunate results.

I'm working on improving my git-fu to collect the pull changes from that
branch, and hope to mail out a patch set shortly.

Cheers,
Kent.