Re: [PATCH] Input: elantech - correct x, y value range for v2 hardware

[JJ Ding <jj_ding@emc.com.tw>]

Hi Éric,

On Mon, 15 Aug 2011 14:45:24 +0200, Éric Piel <E.A.B.Piel@tudelft.nl> wrote:
> On 15-08-11 05:51, JJ Ding wrote:
> > x, y values are actually 12-bit long. Also update protocol document to reflect
> > the change.
> >
> > Signed-off-by: JJ Ding<jj_ding@emc.com.tw>
> > ---
> > Hello List,
> >
> > We are working on adding support for newer elantech touchpad, which we will
> > submit shortly. Along the way I found this error in current code.
> > This is a simple patch to correct x, y value ranges in v2 hardware.
> > Please review, thank you.
> Hello,
> 
> I'm glad to hear Elantech is planning to contribute directly to the 
> Linux driver!
I am glad, too. :)
> 
> In your patch, be careful to the Y axis. ETP_YMAX_V2 is actually set to 
> 760. Compared to the 4095 that can be reached, there might be overflow.
> 
> Do all the v2 hardwares have the same resolution (in which case we can 
> leave 760, or 768)? Or is there a way to query their resolution? 
Newer hardware does have a way to query max x, y ranges. We are going to
submit such a patch, along with other newer hardware support code.
I personally hope to submit the patchset in a few days.
> Otherwise, we could just put ETP_YMAX_V2 = 4095, and ETP_YMIN_V2 = (4095 
> - 768), to be sure we cannot have an overflow. I think that's what is 
> done in the synaptics driver.
> 
> Dmitry, would this seems the correct way to set min/max in 
> input_set_abs_params()?
> 
> Cheers,
> Éric
> 
> 
> >
> >   Documentation/input/elantech.txt |    8 ++++----
> >   drivers/input/mouse/elantech.c   |    8 ++++----
> >   2 files changed, 8 insertions(+), 8 deletions(-)
> >
> > diff --git a/Documentation/input/elantech.txt b/Documentation/input/elantech.txt
> > index db798af..bce9941 100644
> > --- a/Documentation/input/elantech.txt
> > +++ b/Documentation/input/elantech.txt
> > @@ -389,14 +389,14 @@ byte 0:
> >   byte 1:
> >
> >      bit   7   6   5   4   3   2   1   0
> > -	 p7  p6  p5  p4  .  x10 x9  x8
> > +	 p7  p6  p5  p4 x11 x10 x9  x8
> >
> >   byte 2:
> >
> >      bit   7   6   5   4   3   2   1   0
> >   	 x7  x6  x5  x4  x3  x2  x1  x0
> >
> > -         x10..x0 = absolute x value (horizontal)
> > +         x11..x0 = absolute x value (horizontal)
> >
> >   byte 3:
> >
> > @@ -420,7 +420,7 @@ byte 3:
> >   byte 4:
> >
> >      bit   7   6   5   4   3   2   1   0
> > -        p3  p1  p2  p0   .   .  y9  y8
> > +        p3  p1  p2  p0  y11 y10 y9  y8
> >
> >   	 p7..p0 = pressure (not EF113)
> >
> > @@ -429,7 +429,7 @@ byte 5:
> >      bit   7   6   5   4   3   2   1   0
> >           y7  y6  y5  y4  y3  y2  y1  y0
> >
> > -         y9..y0 = absolute y value (vertical)
> > +         y11..y0 = absolute y value (vertical)
> >
> >
> >   4.2.2 Two finger touch
> > diff --git a/drivers/input/mouse/elantech.c b/drivers/input/mouse/elantech.c
> > index 3250356..da161da 100644
> > --- a/drivers/input/mouse/elantech.c
> > +++ b/drivers/input/mouse/elantech.c
> > @@ -290,15 +290,15 @@ static void elantech_report_absolute_v2(struct psmouse *psmouse)
> >   		/* pass through... */
> >   	case 1:
> >   		/*
> > -		 * byte 1:  .   .   .   .   .  x10 x9  x8
> > +		 * byte 1:  .   .   .   .  x11 x10 x9  x8
> >   		 * byte 2: x7  x6  x5  x4  x4  x2  x1  x0
> >   		 */
> > -		x1 = ((packet[1]&  0x07)<<  8) | packet[2];
> > +		x1 = ((packet[1]&  0x0f)<<  8) | packet[2];
> >   		/*
> > -		 * byte 4:  .   .   .   .   .   .  y9  y8
> > +		 * byte 4:  .   .   .   .  y11 y10 y9  y8
> >   		 * byte 5: y7  y6  y5  y4  y3  y2  y1  y0
> >   		 */
> > -		y1 = ETP_YMAX_V2 - (((packet[4]&  0x03)<<  8) | packet[5]);
> > +		y1 = ETP_YMAX_V2 - (((packet[4]&  0x0f)<<  8) | packet[5]);
> >
> >   		input_report_abs(dev, ABS_X, x1);
> >   		input_report_abs(dev, ABS_Y, y1);
> 
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