From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1755226AbcIEI0P (ORCPT ); Mon, 5 Sep 2016 04:26:15 -0400 Received: from eusmtp01.atmel.com ([212.144.249.243]:21433 "EHLO eusmtp01.atmel.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1754934AbcIEI0L (ORCPT ); Mon, 5 Sep 2016 04:26:11 -0400 Subject: Re: [PATCH] iio: adc: at91: Add support for Touchscreen Switches Closure Time To: Jonathan Cameron , Cristian Birsan , Ludovic Desroches References: <20160830122701.19385-1-nicolas.ferre@atmel.com> CC: Alexandre Belloni , , , From: Nicolas Ferre Organization: atmel Message-ID: <51aeb56b-c2f7-461f-065d-c581d3837340@atmel.com> Date: Mon, 5 Sep 2016 10:26:08 +0200 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: Content-Type: text/plain; charset="windows-1252" Content-Transfer-Encoding: 8bit X-Originating-IP: [10.145.133.18] Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org 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, >> --- >> 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; >> > > -- Nicolas Ferre