| Message ID | 20230914212432.2842010-2-robert.hancock@calian.com (mailing list archive) |
|---|---|
| State | New, archived |
| Headers | show |
| Series | Xilinx XADC fixes | expand |
On Thu, 2023-09-14 at 15:24 -0600, Robert Hancock wrote: > In the probe function, the driver was reading out the thresholds > already > set in the core, which can be configured by the user in the Vivado > tools > when the FPGA image is built. However, it later clobbered those > values > with zero or maximum values. In particular, the overtemperature > shutdown > threshold register was overwritten with the max value, which > effectively > prevents the FPGA from shutting down when the desired threshold was > eached, potentially risking hardware damage in that case. > > Remove this code to leave the preconfigured default threshold values > intact. Apparently this change is necessary but not sufficient, as the driver is also disabling all the alarm bits which are needed for the overtemperature shutdown to actually function. Will follow up with a new version shortly. > > Fixes: bdc8cda1d010 ("iio:adc: Add Xilinx XADC driver") > Signed-off-by: Robert Hancock <robert.hancock@calian.com> > --- > drivers/iio/adc/xilinx-xadc-core.c | 16 ---------------- > 1 file changed, 16 deletions(-) > > diff --git a/drivers/iio/adc/xilinx-xadc-core.c > b/drivers/iio/adc/xilinx-xadc-core.c > index dba73300f894..88d523ac7881 100644 > --- a/drivers/iio/adc/xilinx-xadc-core.c > +++ b/drivers/iio/adc/xilinx-xadc-core.c > @@ -1429,22 +1429,6 @@ static int xadc_probe(struct platform_device > *pdev) > if (ret) > return ret; > > - /* Set thresholds to min/max */ > - for (i = 0; i < 16; i++) { > - /* > - * Set max voltage threshold and both temperature > thresholds to > - * 0xffff, min voltage threshold to 0. > - */ > - if (i % 8 < 4 || i == 7) > - xadc->threshold[i] = 0xffff; > - else > - xadc->threshold[i] = 0; > - ret = xadc_write_adc_reg(xadc, XADC_REG_THRESHOLD(i), > - xadc->threshold[i]); > - if (ret) > - return ret; > - } > - > /* Go to non-buffered mode */ > xadc_postdisable(indio_dev); >
diff --git a/drivers/iio/adc/xilinx-xadc-core.c b/drivers/iio/adc/xilinx-xadc-core.c index dba73300f894..88d523ac7881 100644 --- a/drivers/iio/adc/xilinx-xadc-core.c +++ b/drivers/iio/adc/xilinx-xadc-core.c @@ -1429,22 +1429,6 @@ static int xadc_probe(struct platform_device *pdev) if (ret) return ret; - /* Set thresholds to min/max */ - for (i = 0; i < 16; i++) { - /* - * Set max voltage threshold and both temperature thresholds to - * 0xffff, min voltage threshold to 0. - */ - if (i % 8 < 4 || i == 7) - xadc->threshold[i] = 0xffff; - else - xadc->threshold[i] = 0; - ret = xadc_write_adc_reg(xadc, XADC_REG_THRESHOLD(i), - xadc->threshold[i]); - if (ret) - return ret; - } - /* Go to non-buffered mode */ xadc_postdisable(indio_dev);
In the probe function, the driver was reading out the thresholds already set in the core, which can be configured by the user in the Vivado tools when the FPGA image is built. However, it later clobbered those values with zero or maximum values. In particular, the overtemperature shutdown threshold register was overwritten with the max value, which effectively prevents the FPGA from shutting down when the desired threshold was eached, potentially risking hardware damage in that case. Remove this code to leave the preconfigured default threshold values intact. Fixes: bdc8cda1d010 ("iio:adc: Add Xilinx XADC driver") Signed-off-by: Robert Hancock <robert.hancock@calian.com> --- drivers/iio/adc/xilinx-xadc-core.c | 16 ---------------- 1 file changed, 16 deletions(-)