| Message ID | 1414408111-2631-4-git-send-email-vigneshr@ti.com (mailing list archive) |
|---|---|
| State | New, archived |
| Headers | show |
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 <vigneshr@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 { >
On Saturday 01 November 2014 02:39 AM, Hartmut Knaack wrote: > 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. I will address this in v2 >> Signed-off-by: Vignesh R <vigneshr@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 { >> >
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 + avoiding false pen-up event. Start from a lower value say 0x400 + and increase value until false pen-up events are avoided. The + pen-up detection happens immediately after the charge step + 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 {
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. Signed-off-by: Vignesh R <vigneshr@ti.com> --- .../devicetree/bindings/input/touchscreen/ti-tsc-adc.txt | 13 +++++++++++++ arch/arm/boot/dts/am335x-evm.dts | 1 + 2 files changed, 14 insertions(+)