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iio: adc: ad7780: Fix IRQ flag

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Correct IRQ flag here is falling.

In Sigma-Delta devices the SDO line is also used as an interrupt.
Leaving IRQ on level instead of falling might trigger a sample read
when the IRQ is enabled, as the SDO line is already low. Not sure
if SDO line will always immediately go high in ad_sd_buffer_postenable
before the IRQ is enabled.

Also the datasheet seem to explicitly say the falling edge of the SDO
should be used as an interrupt:
>From the AD7780 datasheet: " The DOUT/Figure 22 RDY falling edge
can be used as an interrupt to a processor"

Fixes: da4d3d6bb9 ("iio: adc: ad-sigma-delta: Allow custom IRQ flags")
Signed-off-by: Alexandru Tachici <alexandru.tachici@analog.com>
Cc: <Stable@vger.kernel.org>
Link: https://lore.kernel.org/r/20210906065630.16325-3-alexandru.tachici@analog.com
Signed-off-by: Jonathan Cameron <Jonathan.Cameron@huawei.com>
This commit is contained in:
Alexandru Tachici 2021-09-06 09:56:29 +03:00 committed by Jonathan Cameron
parent 89a86da5cb
commit e081102f30
1 changed files with 1 additions and 1 deletions
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2
drivers/iio/adc/ad7780.c
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@ -203,7 +203,7 @@ static const struct ad_sigma_delta_info ad7780_sigma_delta_info = {
.set_mode = ad7780_set_mode,
.postprocess_sample = ad7780_postprocess_sample,
.has_registers = false,
.irq_flags = IRQF_TRIGGER_LOW,
.irq_flags = IRQF_TRIGGER_FALLING,
};
#define _AD7780_CHANNEL(_bits, _wordsize, _mask_all) \