Re: [PATCH 2/6] dt-bindings: Input: edt-ft5x06 - add disable wakeup-source documentation

[Rob Herring <robh@kernel.org>]

On Tue, Sep 17, 2019 at 10:26:58AM -0700, Dmitry Torokhov wrote:
> On Tue, Sep 17, 2019 at 07:18:14PM +0200, Marco Felsch wrote:
> > Hi Dmitry,
> > 
> > On 19-09-17 10:07, Dmitry Torokhov wrote:
> > > On Tue, Sep 17, 2019 at 05:58:04PM +0200, Marco Felsch wrote:
> > > > The default driver behaviour is to enable the wakeup-source everytime.
> > > > There are hardware designs which have a dedicated gpio to act as wakeup
> > > > device. So it must be allowed to disable the wakeup-source capability.
> > > > 
> > > > This patch adds the binding documentation to disable the wakeup-source
> > > > capability.
> > > > 
> > > > Signed-off-by: Marco Felsch <m.felsch@pengutronix.de>
> > > > ---
> > > >  .../devicetree/bindings/input/touchscreen/edt-ft5x06.txt      | 4 ++++
> > > >  1 file changed, 4 insertions(+)
> > > > 
> > > > diff --git a/Documentation/devicetree/bindings/input/touchscreen/edt-ft5x06.txt b/Documentation/devicetree/bindings/input/touchscreen/edt-ft5x06.txt
> > > > index 870b8c5cce9b..4d6524fe3cf4 100644
> > > > --- a/Documentation/devicetree/bindings/input/touchscreen/edt-ft5x06.txt
> > > > +++ b/Documentation/devicetree/bindings/input/touchscreen/edt-ft5x06.txt
> > > > @@ -35,6 +35,10 @@ Optional properties:
> > > >   - pinctrl-0:   a phandle pointing to the pin settings for the
> > > >                  control gpios
> > > >  
> > > > + - edt,disable-wakeup-source: If left the device will act as wakeup-source
> > > > +			      (for legacy compatibility). Add the property
> > > > +			      so the device won't act as wakeup-source.
> > > 
> > > I think this is too ugly and I consider it being a bug in the driver
> > > that it enables wakeup unconditionally.
> > 
> > That's right.
> > 
> > > Let's just update DTS in tree for devices that actually want it (I am
> > > curious how many that do not declare "wakeup-source" have it working and
> > > actually want it) and key the dirver behavior off the standard property.
> > 
> > There are a few DTS using this driver and the current driver behaviour.
> > We need to keep the backward compatibility since the DTB is part of the
> > firmware and firmware isn't always included during a system-update. I
> > know its ugly but IMHO that's the right way to go to keep the backward
> > compatibility. Let us see what the DT-folk says.
> > 
> > > Until we start seeing this controller in devices that actually have DTS
> > > in hardware device tree I think it is better to use standard property.
> > 
> > Sorry, I didn't get you here..
> 
> What I was trying to say is that I have not actually seen DTB that is
> part of hardware or separately upgradable frimware (not talking about
> ppc or sparc boxes, but ones that might be using this driver). It is
> always built into the kernel in my experience, so backward compatibility
> is simply a tool that is being used to prevent us from being too wild
> with hacking on bindings, but rarely a practical concern.

Well, that's self fulfilling...

> In cases like this I think it is worthwhile to simply update in-tree
> DTS and arrive at a sane binding.

Get the maintainers of the affected platforms to agree to the changes.

Rob