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 <nicolas.ferre@xxxxxxxxx>
> 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
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