iio: mlx90614: Check for errors in read values

The device uses the MSB of the returned temperature value as an error
flag.  Return a read error when this bit is set.

Signed-off-by: Vianney le Clément de Saint-Marcq <vianney.leclement@essensium.com>
Cc: Arnout Vandecappelle (Essensium/Mind) <arnout@mind.be>
Signed-off-by: Jonathan Cameron <jic23@kernel.org>

diff --git a/drivers/iio/temperature/mlx90614.c b/drivers/iio/temperature/mlx90614.c
index 73ec7677496f9fb9a74b664c1bfc63b5edf377ec..06b7b967798233c1fb1c7fb1cd9edb4f81523821 100644 (file)
--- a/drivers/iio/temperature/mlx90614.c
+++ b/drivers/iio/temperature/mlx90614.c
@@ -196,6 +196,11 @@ static int mlx90614_read_raw(struct iio_dev *indio_dev,
 
                if (ret < 0)
                        return ret;
+
+               /* MSB is an error flag */
+               if (ret & 0x8000)
+                       return -EIO;
+
                *val = ret;
                return IIO_VAL_INT;
        case IIO_CHAN_INFO_OFFSET: