linux-kernel - [PATCH 4.4 105/146] iio: hudmidity: hdc100x: fix incorrect shifting and scaling

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Date:	Mon, 25 Jul 2016 13:56:00 -0700
From:	Greg Kroah-Hartman <gregkh@...uxfoundation.org>
To:	linux-kernel@...r.kernel.org
Cc:	Greg Kroah-Hartman <gregkh@...uxfoundation.org>,
	stable@...r.kernel.org, Alison Schofield <amsfield22@...il.com>,
	Matt Ranostay <mranostay@...il.com>,
	Jonathan Cameron <jic23@...nel.org>
Subject: [PATCH 4.4 105/146] iio: hudmidity: hdc100x: fix incorrect shifting and scaling

4.4-stable review patch.  If anyone has any objections, please let me know.

------------------

From: Matt Ranostay <mranostay@...il.com>

commit 94bef000f1d4aa111f4ddda1482cf3b30ad069ce upstream.

Shifting sensor data to the right 2 bits was incorrect and caused the
scaling values + offsets to be invalid.

Reported-by: Alison Schofield <amsfield22@...il.com>
Signed-off-by: Matt Ranostay <mranostay@...il.com>
Tested-by: Alison Schofield <amsfield22@...il.com>
Signed-off-by: Jonathan Cameron <jic23@...nel.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@...uxfoundation.org>

---
 drivers/iio/humidity/hdc100x.c |   16 ++++++++--------
 1 file changed, 8 insertions(+), 8 deletions(-)

--- a/drivers/iio/humidity/hdc100x.c
+++ b/drivers/iio/humidity/hdc100x.c
@@ -164,14 +164,14 @@ static int hdc100x_get_measurement(struc
 		dev_err(&client->dev, "cannot read high byte measurement");
 		return ret;
 	}
-	val = ret << 6;
+	val = ret << 8;
 
 	ret = i2c_smbus_read_byte(client);
 	if (ret < 0) {
 		dev_err(&client->dev, "cannot read low byte measurement");
 		return ret;
 	}
-	val |= ret >> 2;
+	val |= ret;
 
 	return val;
 }
@@ -212,17 +212,17 @@ static int hdc100x_read_raw(struct iio_d
 	case IIO_CHAN_INFO_SCALE:
 		if (chan->type == IIO_TEMP) {
 			*val = 165000;
-			*val2 = 65536 >> 2;
+			*val2 = 65536;
 			return IIO_VAL_FRACTIONAL;
 		} else {
-			*val = 0;
-			*val2 = 10000;
-			return IIO_VAL_INT_PLUS_MICRO;
+			*val = 100;
+			*val2 = 65536;
+			return IIO_VAL_FRACTIONAL;
 		}
 		break;
 	case IIO_CHAN_INFO_OFFSET:
-		*val = -3971;
-		*val2 = 879096;
+		*val = -15887;
+		*val2 = 515151;
 		return IIO_VAL_INT_PLUS_MICRO;
 	default:
 		return -EINVAL;