iio: iio: Fix iio_channel_read return if channel havn't info

When xilinx-xadc is used with hwmon driver to read voltage, offset used
for temperature is always applied whatever the channel.

iio_channel_read must return an error to avoid offset for channel
without IIO_CHAN_INFO_OFFSET property.

Signed-off-by: Fabien Proriol <fabien.proriol@jdsu.com>
Signed-off-by: Jonathan Cameron <jic23@kernel.org>

1 files changed, 3 insertions, 0 deletions

diff --git a/drivers/iio/inkern.c b/drivers/iio/inkern.c
index f0846108d006..d33590e89337 100644
--- a/drivers/iio/inkern.c
+++ b/drivers/iio/inkern.c
@@ -426,6 +426,9 @@ static int iio_channel_read(struct iio_channel *chan, int *val, int *val2,
         if (val2 == NULL)
                 val2 = &unused;
 
+        if(!iio_channel_has_info(chan->channel, info))
+                return -EINVAL;
+
         if (chan->indio_dev->info->read_raw_multi) {
                 ret = chan->indio_dev->info->read_raw_multi(chan->indio_dev,
                                         chan->channel, INDIO_MAX_RAW_ELEMENTS,