4.20-stable review patch. If anyone has any objections, please let me know.
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From: Mircea Caprioru mircea.caprioru@analog.com
commit 0e76df5c978338f3051e5126fc0c4245c57a307a upstream.
This patch solves the register readback issue with the bit shift. When the dac resolution was lower than the register size (ex. 12 bits out of 16 bits) the readback value was not shifted with the difference in bits and the value was higher. Also a mask is applied on the read value in order to get the value relative to the actual bit size.
Fixes: 0357e488b8 ("iio:dac:ad5686: Refactor the driver") Signed-off-by: Mircea Caprioru mircea.caprioru@analog.com 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/dac/ad5686.c | 3 ++- 1 file changed, 2 insertions(+), 1 deletion(-)
--- a/drivers/iio/dac/ad5686.c +++ b/drivers/iio/dac/ad5686.c @@ -124,7 +124,8 @@ static int ad5686_read_raw(struct iio_de mutex_unlock(&indio_dev->mlock); if (ret < 0) return ret; - *val = ret; + *val = (ret >> chan->scan_type.shift) & + GENMASK(chan->scan_type.realbits - 1, 0); return IIO_VAL_INT; case IIO_CHAN_INFO_SCALE: *val = st->vref_mv;