From mboxrd@z Thu Jan 1 00:00:00 1970 From: imrehg@gmail.com (Gergely Imreh) Date: Thu, 11 Jun 2015 16:22:26 +0800 Subject: [PATCH 1/1] iio:adc: XADC: Set offset explicitly to zero on voltage channels Message-ID: <1434010946-8118-1-git-send-email-imrehg@gmail.com> To: linux-arm-kernel@lists.infradead.org List-Id: linux-arm-kernel.lists.infradead.org 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 --- 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