Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1751895AbaKGFtp (ORCPT ); Fri, 7 Nov 2014 00:49:45 -0500 Received: from arroyo.ext.ti.com ([192.94.94.40]:34590 "EHLO arroyo.ext.ti.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751665AbaKGFtd (ORCPT ); Fri, 7 Nov 2014 00:49:33 -0500 Message-ID: <545C5D20.5010006@ti.com> Date: Fri, 7 Nov 2014 11:18:16 +0530 From: Vignesh R User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:31.0) Gecko/20100101 Thunderbird/31.2.0 MIME-Version: 1.0 To: Hartmut Knaack , Rob Herring , Pawel Moll , Mark Rutland , Ian Campbell , Kumar Gala , Benoit Cousson , Tony Lindgren , Russell King , Jonathan Cameron , Dmitry Torokhov CC: Lars-Peter Clausen , Peter Meerwald , Samuel Ortiz , Lee Jones , Felipe Balbi , Sebastian Andrzej Siewior , Jan Kardell , Paul Gortmaker , Brad Griffis , , , , , , Subject: Re: [PATCH 3/4] arm: boot: dts: am335x-evm: Make charge delay a DT parameter for tsc References: <1414408111-2631-1-git-send-email-vigneshr@ti.com> <1414408111-2631-4-git-send-email-vigneshr@ti.com> <5453FA8E.3080204@gmx.de> In-Reply-To: <5453FA8E.3080204@gmx.de> Content-Type: text/plain; charset="iso-8859-15" Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org 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 >> --- >> .../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 { >> > -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/