iio: at91-sama5d2: Fix incorrect sign extension

commit 652e7df485c6884d552085ae2c73efa6cfea3547 upstream.

Use scan_type when processing raw data which also fixes that the sign
extension was from the wrong bit.

Use channel definition as root of trust and replace constant
when reading elements directly using the raw sysfs attributes.

Fixes: 6794e23fa3fe ("iio: adc: at91-sama5d2_adc: add support for oversampling resolution")
Signed-off-by: Gwendal Grignou <gwendal@chromium.org>
Reviewed-by: Eugen Hristev <eugen.hristev@microchip.com>
Cc: <Stable@vger.kernel.org>
Link: https://lore.kernel.org/r/20211104082413.3681212-9-gwendal@chromium.org
Signed-off-by: Jonathan Cameron <Jonathan.Cameron@huawei.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

diff --git a/drivers/iio/adc/at91-sama5d2_adc.c b/drivers/iio/adc/at91-sama5d2_adc.c
index def4abeb47cae11c55a2f7e3dc6021e8e63a7097..8854da453669caedba75b955f8d91e985b4d95b1 100644 (file)
--- a/drivers/iio/adc/at91-sama5d2_adc.c
+++ b/drivers/iio/adc/at91-sama5d2_adc.c
@@ -1369,7 +1369,8 @@ static int at91_adc_read_info_raw(struct iio_dev *indio_dev,
                *val = st->conversion_value;
                ret = at91_adc_adjust_val_osr(st, val);
                if (chan->scan_type.sign == 's')
-                       *val = sign_extend32(*val, 11);
+                       *val = sign_extend32(*val,
+                                            chan->scan_type.realbits - 1);
                st->conversion_done = false;
        }