The Xilinx XADC driver has both a temperature channel and 8 voltage
channels. The voltage channels have no offset, but actually were still
set the same offset as the temperature channel. This did not cause
problems in /sys/bus/iio/ but can cause problems with other drivers
using iio data. For example iio-hwmon did return wrong voltage values
because of the offset.
Change tested with the Parallella board.
Signed-off-by: Gergely Imreh <imrehg@xxxxxxxxx>
---
drivers/iio/adc/xilinx-xadc-core.c | 14 +++++++++++---
1 file changed, 11 insertions(+), 3 deletions(-)
diff --git a/drivers/iio/adc/xilinx-xadc-core.c b/drivers/iio/adc/xilinx-xadc-core.c
index ab52be2..36efab7 100644
--- a/drivers/iio/adc/xilinx-xadc-core.c
+++ b/drivers/iio/adc/xilinx-xadc-core.c
@@ -877,9 +877,17 @@ static int xadc_read_raw(struct iio_dev *indio_dev,
return -EINVAL;
}
case IIO_CHAN_INFO_OFFSET:
- /* Only the temperature channel has an offset */
- *val = -((273150 << 12) / 503975);
- return IIO_VAL_INT;
+ switch (chan->type) {
+ case IIO_VOLTAGE:
+ *val = 0;
+ return IIO_VAL_INT;
+ case IIO_TEMP:
+ /* Only the temperature channel has an offset */
+ *val = -((273150 << 12) / 503975);
+ return IIO_VAL_INT;
+ default:
+ return -EINVAL;
+ }
case IIO_CHAN_INFO_SAMP_FREQ:
ret = xadc_read_adc_reg(xadc, XADC_REG_CONF2, &val16);
if (ret)
--
2.4.2
--
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