Re: [PATCH 0/2] Salvator-X: Add GPIO keys support

[Laurent Pinchart <laurent.pinchart@ideasonboard.com>]

Hi Geert,

On Monday 14 Nov 2016 14:47:00 Geert Uytterhoeven wrote:
> On Mon, Nov 14, 2016 at 2:41 PM, Laurent Pinchart wrote:
> > On Monday 14 Nov 2016 14:35:26 Geert Uytterhoeven wrote:
> >> The main reason I haven't sent out a similar series yet is because the
> >> GPIOs used for the 3 push buttons are shared with the 3 user LEDs. For
> >> each of them, you have to choose at DT time if you want to use them as
> >> buttons or as LEDs.
> >> 
> >> On ULCB, the same issue is present. For those, we settled on 1 key and 2
> >> LEDs...
> >> 
> >> Looking forward to more comments...
> > 
> > In theory the GPIOs could be shared by the gpio-keys and LED drivers in
> > open- drain mode. I'm not sure the GPIO subsystem supports that though.
> 
> Been there, done that, cfr. "[RFD] Sharing GPIOs for input (buttons) and
> output (LEDs)". The result wasn't pretty...

Wasn't it ? Linus basically told you to use open-drain GPIOs and fix the GPIO 
driver in case it can't read the value of GPIOs configured as output in open-
drain mode. If didn't shoot the idea down.

-- 
Regards,

Laurent Pinchart