Messages in this thread | | | Date | Wed, 5 Mar 2014 19:04:58 +0800 | From | Josh Wu <> | Subject | Re: [PATCH] iio: adc: at91_adc: correct default shtim value |
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Hi, Alexandre
On 3/4/2014 2:07 AM, Alexandre Belloni wrote: > 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: Alexandre Belloni <alexandre.belloni@free-electrons.com>
Thanks for the fix and
Acked-by: Josh Wu<josh.wu@atmel.com>
Best Regards, Josh Wu > --- > drivers/iio/adc/at91_adc.c | 7 +++++-- > 1 file changed, 5 insertions(+), 2 deletions(-) > > diff --git a/drivers/iio/adc/at91_adc.c b/drivers/iio/adc/at91_adc.c > index 5b1aa027c034..0b103f905607 100644 > --- a/drivers/iio/adc/at91_adc.c > +++ b/drivers/iio/adc/at91_adc.c > @@ -1004,8 +1004,11 @@ 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;
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