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From:   Sasha Levin <sashal@kernel.org>
To:     stable@vger.kernel.org, linux-kernel@vger.kernel.org
Cc:     Fabien Proriol <fabien.proriol@jdsu.com>,
        Jonathan Cameron <jic23@kernel.org>,
        Sasha Levin <sashal@kernel.org>
Subject: [PATCH AUTOSEL 3.18 21/98] iio: iio: Fix iio_channel_read return if channel havn't info
Date:   Thu, 25 Oct 2018 10:17:36 -0400
Message-Id: <20181025141853.214051-21-sashal@kernel.org>
In-Reply-To: <20181025141853.214051-1-sashal@kernel.org>
References: <20181025141853.214051-1-sashal@kernel.org>
Sender: linux-kernel-owner@vger.kernel.org
Precedence: bulk

From: Fabien Proriol <fabien.proriol@jdsu.com>

[ Upstream commit 65de7654d39c70c2b942f801cea01590cf7e3458 ]

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>
Signed-off-by: Sasha Levin <sashal@kernel.org>
---
 drivers/iio/inkern.c | 3 +++
 1 file changed, 3 insertions(+)

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,
-- 
2.17.1