[PATCH 4.14 039/117] iio: xilinx-xadc: Fix ADC-B powerdown

From: Greg Kroah-Hartman
Date: Fri May 01 2020 - 09:32:57 EST


From: Lars-Peter Clausen <lars@xxxxxxxxxx>

commit e44ec7794d88f918805d700240211a9ec05ed89d upstream.

The check for shutting down the second ADC is inverted. This causes it to
be powered down when it should be enabled. As a result channels that are
supposed to be handled by the second ADC return invalid conversion results.

Signed-off-by: Lars-Peter Clausen <lars@xxxxxxxxxx>
Fixes: bdc8cda1d010 ("iio:adc: Add Xilinx XADC driver")
Cc: <Stable@xxxxxxxxxxxxxxx>
Signed-off-by: Jonathan Cameron <Jonathan.Cameron@xxxxxxxxxx>
Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>

---
drivers/iio/adc/xilinx-xadc-core.c | 5 +++--
1 file changed, 3 insertions(+), 2 deletions(-)

--- a/drivers/iio/adc/xilinx-xadc-core.c
+++ b/drivers/iio/adc/xilinx-xadc-core.c
@@ -709,13 +709,14 @@ static int xadc_power_adc_b(struct xadc
{
uint16_t val;

+ /* Powerdown the ADC-B when it is not needed. */
switch (seq_mode) {
case XADC_CONF1_SEQ_SIMULTANEOUS:
case XADC_CONF1_SEQ_INDEPENDENT:
- val = XADC_CONF2_PD_ADC_B;
+ val = 0;
break;
default:
- val = 0;
+ val = XADC_CONF2_PD_ADC_B;
break;
}