Vignesh R schrieb am 27.10.2014 12:08:
> The charge delay value is by default 0xB000. But it can be set to lower
> values on some boards as long as false pen-ups are avoided. Lowering the
> value increases the sampling rate (though current sampling rate is
> sufficient for tsc operation). Hence charge delay has been made a DT
> parameter.
>
I would recommend to use a few colons to separate some thoughts. Also, limit to
80 chars per line would be beneficial. See inline.
> Signed-off-by: Vignesh R <vigne...@ti.com>
> ---
> .../devicetree/bindings/input/touchscreen/ti-tsc-adc.txt | 13
> +++++++++++++
> arch/arm/boot/dts/am335x-evm.dts | 1 +
> 2 files changed, 14 insertions(+)
>
> diff --git
> a/Documentation/devicetree/bindings/input/touchscreen/ti-tsc-adc.txt
> b/Documentation/devicetree/bindings/input/touchscreen/ti-tsc-adc.txt
> index 878549ba814d..ac62769e70e4 100644
> --- a/Documentation/devicetree/bindings/input/touchscreen/ti-tsc-adc.txt
> +++ b/Documentation/devicetree/bindings/input/touchscreen/ti-tsc-adc.txt
> @@ -28,6 +28,18 @@ Required properties:
> ti,adc-channels: List of analog inputs available for ADC.
> AIN0 = 0, AIN1 = 1 and so on till AIN7 = 7.
>
> +Optional properties:
> +- child "tsc"
> + ti,charge-delay: Length of touch screen charge delay step in terms of
> + ADC clock cycles. Charge delay value should be large
> in order
> + to avoid false pen-up events. This value affects the
> overall
> + sampling speed hence need to be kept as low as
> possible while
<...> speed, hence needs to be <...>
> + avoiding false pen-up event. Start from a lower value
> say 0x400
<...> pen-up events. Start from a lower value, like 0x400, and increase <...>
> + and increase value until false pen-up events are
> avoided. The
> + pen-up detection happens immediately after the charge
> step
<...> charge step, so this <...>
> + so this does in fact function as a hardware knob for
> adjusting
> + the amount of "settling time".
> +
> Example:
> tscadc: tscadc@44e0d000 {
> compatible = "ti,am3359-tscadc";
> @@ -36,6 +48,7 @@ Example:
> ti,x-plate-resistance = <200>;
> ti,coordiante-readouts = <5>;
> ti,wire-config = <0x00 0x11 0x22 0x33>;
> + ti,charge-delay = <0xB000>;
> };
>
> adc {
> diff --git a/arch/arm/boot/dts/am335x-evm.dts
> b/arch/arm/boot/dts/am335x-evm.dts
> index e2156a583de7..80be0462298b 100644
> --- a/arch/arm/boot/dts/am335x-evm.dts
> +++ b/arch/arm/boot/dts/am335x-evm.dts
> @@ -641,6 +641,7 @@
> ti,x-plate-resistance = <200>;
> ti,coordinate-readouts = <5>;
> ti,wire-config = <0x00 0x11 0x22 0x33>;
> + ti,charge-delay = <0xB000>;
> };
>
> adc {
>
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