Re: [PATCH 3/5] dt-bindings: add more optional properties for elan_i2c touchpads

From: Benjamin Tissoires <benjamin.tissoires@redhat.com>
To: robh@kernel.org, Hans de Goede <hdegoede@redhat.com>
Cc: "Dmitry Torokhov" <dmitry.torokhov@gmail.com>,
	廖崇榮 <kt.liao@emc.com.tw>,
	"open list:HID CORE LAYER" <linux-input@vger.kernel.org>,
	lkml <linux-kernel@vger.kernel.org>,
	devicetree@vger.kernel.org
Subject: Re: [PATCH 3/5] dt-bindings: add more optional properties for elan_i2c touchpads
Date: Thu, 18 Oct 2018 10:10:44 +0200	[thread overview]
Message-ID: <CAO-hwJ+z6YdnLdbzeh-7f99cBBjHfbLKLzKo-fQQaC_W8bt_Uw@mail.gmail.com> (raw)
In-Reply-To: <20181017201522.GA26525@bogus>

On Wed, Oct 17, 2018 at 10:15 PM Rob Herring <robh@kernel.org> wrote:
>
> On Fri, Oct 12, 2018 at 04:24:11PM +0200, Benjamin Tissoires wrote:
> > Some new touchpads IC are connected through PS/2 and I2C. On some of these
> > new IC, the I2C part doesn't have all of the information available.
> > We need to be able to forward the touchpad parameters from PS/2 and
> > thus, we need those new optional properties.
> >
> > Link: https://bugzilla.redhat.com/show_bug.cgi?id=1628715
> > Signed-off-by: Benjamin Tissoires <benjamin.tissoires@redhat.com>
> > ---
> >  Documentation/devicetree/bindings/input/elan_i2c.txt | 8 ++++++++
> >  1 file changed, 8 insertions(+)
> >
> > diff --git a/Documentation/devicetree/bindings/input/elan_i2c.txt b/Documentation/devicetree/bindings/input/elan_i2c.txt
> > index 797607460735..ace6bcb0b4eb 100644
> > --- a/Documentation/devicetree/bindings/input/elan_i2c.txt
> > +++ b/Documentation/devicetree/bindings/input/elan_i2c.txt
> > @@ -13,6 +13,14 @@ Optional properties:
> >    pinctrl binding [1]).
> >  - vcc-supply: a phandle for the regulator supplying 3.3V power.
> >  - elan,trackpoint: touchpad can support a trackpoint (boolean)
> > +- elan,clickpad: touchpad is a clickpad (the entire surface is a button)
>
> > +- elan,max_x: the maximum reported value on the X axis
> > +- elan,max_y: the maximum reported value on the Y axis
> > +- elan,min_x: the minimum reported value on the X axis
> > +- elan,min_y: the minimum reported value on the Y axis
> > +- elan,x_res: the resolution of the X axis (in units per mm)
> > +- elan,y_res: the resolution of the Y axis (in units per mm)
> > +- elan,width: max reported width of a blob
>
> Can't we use standard touchscreen properties here? (Yes, I get this is a
> touchpad, not touchscreen).

Hey Rob,

Well, there is that (it's a touchpad driver) and we can't also really
use the of_touchscreen.c implementation.
If both concerns are not an issue, we can then move the [min/max/res]
properties to the touchscreen ones.

Regarding 'elan,width', this is something missing from the standard ts
properties, and AFAICT, this controls the maximum reported
width/height of a touch.
I should probably rename them to max_width, max_height.

Hans, do you think we should add such properties to of_touchscreen.c
too? (the width/height ones)

Cheers,
Benjamin