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

["Éric Piel" <E.A.B.Piel@tudelft.nl>]

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!

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? 
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);

--
To unsubscribe from this list: send the line "unsubscribe linux-input" in
the body of a message to majordomo@vger.kernel.org
More majordomo info at  http://vger.kernel.org/majordomo-info.html