Re: [PATCH v2 8/8] DT:omap3+ads7846: use new common touchscreen bindings

[Grazvydas Ignotas]

Hi,

On Fri, Nov 13, 2015 at 10:35 PM, H. Nikolaus Schaller
<hns@xxxxxxxxxxxxx> wrote:
> The standard touch screen bindings [1] replace the private ti,swap-xy
> with touchscreen-swaped-x-y. And for the Openpandora we use
> touchscreen-size etc. to match the LCD screen size.
>
> [1]: Documentation/devicetree/bindings/input/touchscreen/touchscreen.txt
>
> Signed-off-by: H. Nikolaus Schaller <hns@xxxxxxxxxxxxx>
> ---
>  arch/arm/boot/dts/omap3-lilly-a83x.dtsi              |  2 +-
>  arch/arm/boot/dts/omap3-pandora-common.dtsi          | 17 +++++++++++++----
>  arch/arm/boot/dts/omap3-panel-sharp-ls037v7dw01.dtsi |  2 +-
>  3 files changed, 15 insertions(+), 6 deletions(-)
>
> diff --git a/arch/arm/boot/dts/omap3-lilly-a83x.dtsi b/arch/arm/boot/dts/omap3-lilly-a83x.dtsi
> index d0dd036..01dae66 100644
> --- a/arch/arm/boot/dts/omap3-lilly-a83x.dtsi
> +++ b/arch/arm/boot/dts/omap3-lilly-a83x.dtsi
> @@ -325,7 +325,7 @@
>                 ti,y-max = /bits/ 16 <3600>;
>                 ti,x-plate-ohms = /bits/ 16 <80>;
>                 ti,pressure-max = /bits/ 16 <255>;
> -               ti,swap-xy;
> +               touchscreen-swapped-x-y;
>
>                 linux,wakeup;
>         };
> diff --git a/arch/arm/boot/dts/omap3-pandora-common.dtsi b/arch/arm/boot/dts/omap3-pandora-common.dtsi
> index f672a04..9497cc6 100644
> --- a/arch/arm/boot/dts/omap3-pandora-common.dtsi
> +++ b/arch/arm/boot/dts/omap3-pandora-common.dtsi
> @@ -696,10 +696,19 @@
>                 pendown-gpio = <&gpio3 30 0>;
>                 vcc-supply = <&vaux4>;
>
> -               ti,x-min = /bits/ 16 <0>;
> -               ti,x-max = /bits/ 16 <8000>;
> -               ti,y-min = /bits/ 16 <0>;
> -               ti,y-max = /bits/ 16 <4800>;
> +               touchscreen-size-x = <800>;
> +               touchscreen-size-y = <480>;
> +               touchscreen-max-pressure = <1000>;
> +               touchscreen-fuzz-x = <16>;
> +               touchscreen-fuzz-y = <16>;
> +               touchscreen-fuzz-pressure = <10>;
> +               touchscreen-inverted-x;
> +               touchscreen-inverted-y;
> +
> +               ti,x-min = /bits/ 16 <160>;
> +               ti,x-max = /bits/ 16 <3900>;
> +               ti,y-min = /bits/ 16 <220>;
> +               ti,y-max = /bits/ 16 <3750>;

I'm not sure this is a good idea, there have been at least 3 different
batches of LCDs which slightly different touchscreens attached, with
such thresholds we might end up with unreachable touchscreen points on
some units. If I understand right, calibration won't help if for some
screen locations ADC reading goes below/above these min/max thresholds
on some specific units? If so there should probably be at least 10%
margin in either case to make calibration useful.

GraÅvydas
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