[PATCH 3/4] staging:iio:ad5933: Report temperature as raw value

[Lars-Peter Clausen <lars@metafoo.de>]

We shouldn't be doing the unit conversion in kernel space. Just report the
raw value for the property and the scale. Userspace can do the conversion if
necessary.

Signed-off-by: Lars-Peter Clausen <lars@metafoo.de>
---
 drivers/staging/iio/impedance-analyzer/ad5933.c | 17 ++++++++---------
 1 file changed, 8 insertions(+), 9 deletions(-)

diff --git a/drivers/staging/iio/impedance-analyzer/ad5933.c b/drivers/staging/iio/impedance-analyzer/ad5933.c
index b6bd609..ebff637 100644
--- a/drivers/staging/iio/impedance-analyzer/ad5933.c
+++ b/drivers/staging/iio/impedance-analyzer/ad5933.c
@@ -113,7 +113,8 @@ static const struct iio_chan_spec ad5933_channels[] = {
 		.type = IIO_TEMP,
 		.indexed = 1,
 		.channel = 0,
-		.info_mask_separate = BIT(IIO_CHAN_INFO_PROCESSED),
+		.info_mask_separate = BIT(IIO_CHAN_INFO_RAW) |
+			BIT(IIO_CHAN_INFO_SCALE),
 		.address = AD5933_REG_TEMP_DATA,
 		.scan_index = -1,
 		.scan_type = {
@@ -522,10 +523,9 @@ static int ad5933_read_raw(struct iio_dev *indio_dev,
 	__be16 dat;
 	int ret = -EINVAL;
 
-	mutex_lock(&indio_dev->mlock);
 	switch (m) {
 	case IIO_CHAN_INFO_RAW:
-	case IIO_CHAN_INFO_PROCESSED:
+		mutex_lock(&indio_dev->mlock);
 		if (iio_buffer_enabled(indio_dev)) {
 			ret = -EBUSY;
 			goto out;
@@ -543,14 +543,13 @@ static int ad5933_read_raw(struct iio_dev *indio_dev,
 		if (ret < 0)
 			goto out;
 		mutex_unlock(&indio_dev->mlock);
-		ret = be16_to_cpu(dat);
-		/* Temp in Milli degrees Celsius */
-		if (ret < 8192)
-			*val = ret * 1000 / 32;
-		else
-			*val = (ret - 16384) * 1000 / 32;
+		*val = sign_extend32(be16_to_cpu(dat), 13);
 
 		return IIO_VAL_INT;
+	case IIO_CHAN_INFO_SCALE:
+		*val = 1000;
+		*val2 = 5;
+		return IIO_VAL_FRACTIONAL_LOG2;
 	}
 
 out:
-- 
1.8.0