From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1754332AbcICQZO (ORCPT ); Sat, 3 Sep 2016 12:25:14 -0400 Received: from saturn.retrosnub.co.uk ([178.18.118.26]:45205 "EHLO saturn.retrosnub.co.uk" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1754273AbcICQZM (ORCPT ); Sat, 3 Sep 2016 12:25:12 -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> Cc: Alexandre Belloni , linux-arm-kernel@lists.infradead.org, linux-kernel@vger.kernel.org, linux-iio@vger.kernel.org From: Jonathan Cameron Message-ID: Date: Sat, 3 Sep 2016 17:24:43 +0100 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:45.0) Gecko/20100101 Thunderbird/45.2.0 MIME-Version: 1.0 In-Reply-To: <20160830122701.19385-1-nicolas.ferre@atmel.com> Content-Type: text/plain; charset=windows-1252 Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org 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? 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; >