From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S936345AbcIEUMO (ORCPT ); Mon, 5 Sep 2016 16:12:14 -0400 Received: from saturn.retrosnub.co.uk ([178.18.118.26]:58063 "EHLO saturn.retrosnub.co.uk" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S932319AbcIEUMK (ORCPT ); Mon, 5 Sep 2016 16:12:10 -0400 Subject: Re: [PATCH] iio: adc: at91: Add support for Touchscreen Switches Closure Time To: Nicolas Ferre , Cristian Birsan , Ludovic Desroches References: <20160830122701.19385-1-nicolas.ferre@atmel.com> <51aeb56b-c2f7-461f-065d-c581d3837340@atmel.com> Cc: Alexandre Belloni , linux-arm-kernel@lists.infradead.org, linux-kernel@vger.kernel.org, linux-iio@vger.kernel.org From: Jonathan Cameron Message-ID: <21de9d89-8c28-a750-f74c-ef6953a430dc@kernel.org> Date: Mon, 5 Sep 2016 21:12:07 +0100 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:45.0) Gecko/20100101 Thunderbird/45.3.0 MIME-Version: 1.0 In-Reply-To: <51aeb56b-c2f7-461f-065d-c581d3837340@atmel.com> Content-Type: text/plain; charset=windows-1252 Content-Transfer-Encoding: 8bit Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On 05/09/16 09:26, Nicolas Ferre wrote: > Le 03/09/2016 à 18:24, Jonathan Cameron a écrit : >> On 30/08/16 13:27, Nicolas Ferre wrote: >>> On newer components compatible with the at91sam9x5, the Touchscreen >>> Switches Closure Time or TSSCTIM value of the Touchscreen Mode Register is >>> not filled at all. >>> On some hardware, having no time indicated for it may lead to incoherent >>> values and jitter. >>> We fix this time to 10us as it is usually difficult to retrieve impedance >>> values from LCD manufacturers. >>> >>> Signed-off-by: Nicolas Ferre >> Hi Nicolas, >> >> Stable / fixes material or just have it head for the next merge window? > > Well, I would say that it's an addition of a feature that fixes a bad > behavior ;-) > So, in summary, I would just add it to next kernel revision. > > Thanks for the heads-up. Bye, Thanks Applied to the togreg branch of iio.git - initially pushed out as testing for the autobuilders to play with it. Jonathan > > >>> --- >>> drivers/iio/adc/at91_adc.c | 13 +++++++++++++ >>> 1 file changed, 13 insertions(+) >>> >>> diff --git a/drivers/iio/adc/at91_adc.c b/drivers/iio/adc/at91_adc.c >>> index 0438c68015e8..bbdac07f4aaa 100644 >>> --- a/drivers/iio/adc/at91_adc.c >>> +++ b/drivers/iio/adc/at91_adc.c >>> @@ -113,6 +113,7 @@ >>> #define AT91_ADC_TSMR_TSAV (3 << 4) /* Averages samples */ >>> #define AT91_ADC_TSMR_TSAV_(x) ((x) << 4) >>> #define AT91_ADC_TSMR_SCTIM (0x0f << 16) /* Switch closure time */ >>> +#define AT91_ADC_TSMR_SCTIM_(x) ((x) << 16) >>> #define AT91_ADC_TSMR_PENDBC (0x0f << 28) /* Pen Debounce time */ >>> #define AT91_ADC_TSMR_PENDBC_(x) ((x) << 28) >>> #define AT91_ADC_TSMR_NOTSDMA (1 << 22) /* No Touchscreen DMA */ >>> @@ -150,6 +151,7 @@ >>> #define MAX_RLPOS_BITS 10 >>> #define TOUCH_SAMPLE_PERIOD_US_RL 10000 /* 10ms, the SoC can't keep up with 2ms */ >>> #define TOUCH_SHTIM 0xa >>> +#define TOUCH_SCTIM_US 10 /* 10us for the Touchscreen Switches Closure Time */ >>> >>> /** >>> * struct at91_adc_reg_desc - Various informations relative to registers >>> @@ -1001,7 +1003,9 @@ static void atmel_ts_close(struct input_dev *dev) >>> >>> static int at91_ts_hw_init(struct at91_adc_state *st, u32 adc_clk_khz) >>> { >>> + struct iio_dev *idev = iio_priv_to_dev(st); >>> u32 reg = 0; >>> + u32 tssctim = 0; >>> int i = 0; >>> >>> /* a Pen Detect Debounce Time is necessary for the ADC Touch to avoid >>> @@ -1034,11 +1038,20 @@ static int at91_ts_hw_init(struct at91_adc_state *st, u32 adc_clk_khz) >>> return 0; >>> } >>> >>> + /* Touchscreen Switches Closure time needed for allowing the value to >>> + * stabilize. >>> + * Switch Closure Time = (TSSCTIM * 4) ADCClock periods >>> + */ >>> + tssctim = DIV_ROUND_UP(TOUCH_SCTIM_US * adc_clk_khz / 1000, 4); >>> + dev_dbg(&idev->dev, "adc_clk at: %d KHz, tssctim at: %d\n", >>> + adc_clk_khz, tssctim); >>> + >>> if (st->touchscreen_type == ATMEL_ADC_TOUCHSCREEN_4WIRE) >>> reg = AT91_ADC_TSMR_TSMODE_4WIRE_PRESS; >>> else >>> reg = AT91_ADC_TSMR_TSMODE_5WIRE; >>> >>> + reg |= AT91_ADC_TSMR_SCTIM_(tssctim) & AT91_ADC_TSMR_SCTIM; >>> reg |= AT91_ADC_TSMR_TSAV_(st->caps->ts_filter_average) >>> & AT91_ADC_TSMR_TSAV; >>> reg |= AT91_ADC_TSMR_PENDBC_(st->ts_pendbc) & AT91_ADC_TSMR_PENDBC; >>> >> >> > >