From: Jonathan Cameron <jic23@kernel.org>
To: Nicolas Ferre <nicolas.ferre@atmel.com>,
Cristian Birsan <cristian.birsan@microchip.com>,
Ludovic Desroches <ludovic.desroches@atmel.com>
Cc: Alexandre Belloni <alexandre.belloni@free-electrons.com>,
linux-arm-kernel@lists.infradead.org,
linux-kernel@vger.kernel.org, linux-iio@vger.kernel.org
Subject: Re: [PATCH] iio: adc: at91: Add support for Touchscreen Switches Closure Time
Date: Sat, 3 Sep 2016 17:24:43 +0100 [thread overview]
Message-ID: <b7dcd8e4-db9e-a9ee-352f-b7b77d57cc7a@kernel.org> (raw)
In-Reply-To: <20160830122701.19385-1-nicolas.ferre@atmel.com>
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 <nicolas.ferre@atmel.com>
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;
>
next prev parent reply other threads:[~2016-09-03 16:25 UTC|newest]
Thread overview: 4+ messages / expand[flat|nested] mbox.gz Atom feed top
2016-08-30 12:27 [PATCH] iio: adc: at91: Add support for Touchscreen Switches Closure Time Nicolas Ferre
2016-09-03 16:24 ` Jonathan Cameron [this message]
2016-09-05 8:26 ` Nicolas Ferre
2016-09-05 20:12 ` Jonathan Cameron
Reply instructions:
You may reply publicly to this message via plain-text email
using any one of the following methods:
* Save the following mbox file, import it into your mail client,
and reply-to-all from there: mbox
Avoid top-posting and favor interleaved quoting:
https://en.wikipedia.org/wiki/Posting_style#Interleaved_style
* Reply using the --to, --cc, and --in-reply-to
switches of git-send-email(1):
git send-email \
--in-reply-to=b7dcd8e4-db9e-a9ee-352f-b7b77d57cc7a@kernel.org \
--to=jic23@kernel.org \
--cc=alexandre.belloni@free-electrons.com \
--cc=cristian.birsan@microchip.com \
--cc=linux-arm-kernel@lists.infradead.org \
--cc=linux-iio@vger.kernel.org \
--cc=linux-kernel@vger.kernel.org \
--cc=ludovic.desroches@atmel.com \
--cc=nicolas.ferre@atmel.com \
/path/to/YOUR_REPLY
https://kernel.org/pub/software/scm/git/docs/git-send-email.html
* If your mail client supports setting the In-Reply-To header
via mailto: links, try the mailto: link
Be sure your reply has a Subject: header at the top and a blank line
before the message body.
This is a public inbox, see mirroring instructions
for how to clone and mirror all data and code used for this inbox;
as well as URLs for NNTP newsgroup(s).