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Commit 8f32b6ba authored by Alexandre Belloni's avatar Alexandre Belloni Committed by Jonathan Cameron
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iio: adc: at91_adc: correct default shtim value 



When sample_hold_time is zero (this is the case when DT is not used or if
atmel,adc-sample-hold-time is omitted), then the calculated shtim is large.

Make that 0, which is the default for that register and the ADC will then use a
sane value of 2/ADCCLK or 1/ADCCLK depending on the version.

Signed-off-by: default avatarAlexandre Belloni <alexandre.belloni@free-electrons.com>
Acked-by: default avatarJosh Wu <josh.wu@atmel.com>
Signed-off-by: default avatarJonathan Cameron <jic23@kernel.org>
parent 301841a6

drivers/iio/adc/at91_adc.c

+5 −2
Original line number Diff line number Diff line
@@ -1007,8 +1007,11 @@ static int at91_adc_probe(struct platform_device *pdev) 
	 * the best converted final value between two channels selection

	 * The formula thus is : Sample and Hold Time = (shtim + 1) / ADCClock

	 */

	shtim = round_up((st->sample_hold_time * adc_clk_khz /

			  1000) - 1, 1);

	if (st->sample_hold_time > 0)

		shtim = round_up((st->sample_hold_time * adc_clk_khz / 1000)

				 - 1, 1);

	else

		shtim = 0;



	reg = AT91_ADC_PRESCAL_(prsc) & st->registers->mr_prescal_mask;

	reg |= AT91_ADC_STARTUP_(ticks) & st->registers->mr_startup_mask;