6.12-stable review patch. If anyone has any objections, please let me know.
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From: David Lechner dlechner@baylibre.com
commit 7cdfbc0113d087348b8e65dd79276d0f57b89a10 upstream.
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: d1efcf8871db ("iio: adc: ad7944: add driver for AD7944/AD7985/AD7986") Signed-off-by: David Lechner dlechner@baylibre.com Reviewed-by: Nuno Sá nuno.sa@analog.com Link: https://patch.msgid.link/20250505-iio-adc-ad7944-max-high-bits-on-direct-rea... Cc: Stable@vger.kernel.org Signed-off-by: Jonathan Cameron Jonathan.Cameron@huawei.com Signed-off-by: Greg Kroah-Hartman gregkh@linuxfoundation.org --- drivers/iio/adc/ad7944.c | 2 ++ 1 file changed, 2 insertions(+)
--- a/drivers/iio/adc/ad7944.c +++ b/drivers/iio/adc/ad7944.c @@ -290,6 +290,8 @@ static int ad7944_single_conversion(stru
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; }