Commit 7cdfbc01 authored by David Lechner's avatar David Lechner Committed by Jonathan Cameron
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iio: adc: ad7944: mask high bits on direct read 



Apply a mask to the raw value received over the SPI bus for unsigned
direct reads. As we found recently, SPI controllers may not set unused
bits to 0 when reading with bits_per_word != {8,16,32}. The ad7944 uses
bits_per_word of 14 and 18, so we need to mask the value to be sure we
returning the correct value to userspace during a direct read.

Fixes: d1efcf88 ("iio: adc: ad7944: add driver for AD7944/AD7985/AD7986")
Signed-off-by: default avatarDavid Lechner <dlechner@baylibre.com>
Reviewed-by: default avatarNuno Sá <nuno.sa@analog.com>
Link: https://patch.msgid.link/20250505-iio-adc-ad7944-max-high-bits-on-direct-read-v1-1-b173facceefe@baylibre.com


Cc: <Stable@vger.kernel.org>
Signed-off-by: default avatarJonathan Cameron <Jonathan.Cameron@huawei.com>
parent 499a8cee

drivers/iio/adc/ad7944.c

+2 −0
Original line number Diff line number Diff line
@@ -377,6 +377,8 @@ static int ad7944_single_conversion(struct ad7944_adc *adc, 


	if (chan->scan_type.sign == 's')

		*val = sign_extend32(*val, chan->scan_type.realbits - 1);

	else

		*val &= GENMASK(chan->scan_type.realbits - 1, 0);



	return IIO_VAL_INT;

}