iio: Fix two mpl3115 issues in measurement conversion

(i) pressure is 20-bit unsigned, not signed; the buffer description
is incorrect; for raw reads, this is just cosmetic

(ii) temperature is 12-bit signed, not 16-bit; this affects
readout of temperatures below zero as the sign bit is incorrectly
processed

reported via private mail

Cc: stable@vger.kernel.org
Signed-off-by: Peter Meerwald <pmeerw@pmeerw.net>
Reported-by: Robert Deliën <robert@delien.nl>
Signed-off-by: Jonathan Cameron <jic23@kernel.org>

1 files changed, 3 insertions, 3 deletions

diff --git a/drivers/iio/pressure/mpl3115.c b/drivers/iio/pressure/mpl3115.c
index ba6d0c520e63..01b2e0b18878 100644
--- a/drivers/iio/pressure/mpl3115.c
+++ b/drivers/iio/pressure/mpl3115.c
@@ -98,7 +98,7 @@ static int mpl3115_read_raw(struct iio_dev *indio_dev,
                         mutex_unlock(&data->lock);
                         if (ret < 0)
                                 return ret;
-                        *val = sign_extend32(be32_to_cpu(tmp) >> 12, 23);
+                        *val = be32_to_cpu(tmp) >> 12;
                         return IIO_VAL_INT;
                 case IIO_TEMP: /* in 0.0625 celsius / LSB */
                         mutex_lock(&data->lock);
@@ -112,7 +112,7 @@ static int mpl3115_read_raw(struct iio_dev *indio_dev,
                         mutex_unlock(&data->lock);
                         if (ret < 0)
                                 return ret;
-                        *val = sign_extend32(be32_to_cpu(tmp) >> 20, 15);
+                        *val = sign_extend32(be32_to_cpu(tmp) >> 20, 11);
                         return IIO_VAL_INT;
                 default:
                         return -EINVAL;
@@ -185,7 +185,7 @@ static const struct iio_chan_spec mpl3115_channels[] = {
                         BIT(IIO_CHAN_INFO_SCALE),
                 .scan_index = 0,
                 .scan_type = {
-                        .sign = 's',
+                        .sign = 'u',
                         .realbits = 20,
                         .storagebits = 32,
                         .shift = 12,