This is a note to let you know that I've just added the patch titled
iio: adc: ad7944: mask high bits on direct read
to my char-misc git tree which can be found at git://git.kernel.org/pub/scm/linux/kernel/git/gregkh/char-misc.git in the char-misc-next branch.
The patch will show up in the next release of the linux-next tree (usually sometime within the next 24 hours during the week.)
The patch will also be merged in the next major kernel release during the merge window.
If you have any questions about this process, please let me know.
From 7cdfbc0113d087348b8e65dd79276d0f57b89a10 Mon Sep 17 00:00:00 2001 From: David Lechner dlechner@baylibre.com Date: Mon, 5 May 2025 13:28:40 -0500 Subject: iio: adc: ad7944: mask high bits on direct read MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit
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 --- drivers/iio/adc/ad7944.c | 2 ++ 1 file changed, 2 insertions(+)
diff --git a/drivers/iio/adc/ad7944.c b/drivers/iio/adc/ad7944.c index 2f949fe55873..37a137bd8357 100644 --- a/drivers/iio/adc/ad7944.c +++ b/drivers/iio/adc/ad7944.c @@ -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; }