| Message ID | 20200403132717.24682-2-lars@metafoo.de (mailing list archive) |
|---|---|
| State | New, archived |
| Headers | show |
| Series | [1/5] iio: xilinx-xadc: Fix ADC-B powerdown | expand |
On Fri, 3 Apr 2020 15:27:14 +0200 Lars-Peter Clausen <lars@metafoo.de> wrote: > When enabling the trigger and unmasking the end-of-sequence (EOS) interrupt > the EOS interrupt should be cleared from the status register. Otherwise it > is possible that it was still set from a previous capture. If that is the > case the interrupt would fire immediately even though no conversion has > been done yet and stale data is being read from the device. > > The old code only clears the interrupt if the interrupt was previously > unmasked. Which does not make much sense since the interrupt is always > masked at this point and in addition masking the interrupt does not clear > the interrupt from the status register. So the clearing needs to be done > unconditionally. > > Signed-off-by: Lars-Peter Clausen <lars@metafoo.de> Looks good but were is my fixes tag? :) I fear we have a theme here! Jonathan > --- > drivers/iio/adc/xilinx-xadc-core.c | 2 +- > 1 file changed, 1 insertion(+), 1 deletion(-) > > diff --git a/drivers/iio/adc/xilinx-xadc-core.c b/drivers/iio/adc/xilinx-xadc-core.c > index 4fcf1729341f..04a2a609ced4 100644 > --- a/drivers/iio/adc/xilinx-xadc-core.c > +++ b/drivers/iio/adc/xilinx-xadc-core.c > @@ -674,7 +674,7 @@ static int xadc_trigger_set_state(struct iio_trigger *trigger, bool state) > > spin_lock_irqsave(&xadc->lock, flags); > xadc_read_reg(xadc, XADC_AXI_REG_IPIER, &val); > - xadc_write_reg(xadc, XADC_AXI_REG_IPISR, val & XADC_AXI_INT_EOS); > + xadc_write_reg(xadc, XADC_AXI_REG_IPISR, XADC_AXI_INT_EOS); > if (state) > val |= XADC_AXI_INT_EOS; > else
diff --git a/drivers/iio/adc/xilinx-xadc-core.c b/drivers/iio/adc/xilinx-xadc-core.c index 4fcf1729341f..04a2a609ced4 100644 --- a/drivers/iio/adc/xilinx-xadc-core.c +++ b/drivers/iio/adc/xilinx-xadc-core.c @@ -674,7 +674,7 @@ static int xadc_trigger_set_state(struct iio_trigger *trigger, bool state) spin_lock_irqsave(&xadc->lock, flags); xadc_read_reg(xadc, XADC_AXI_REG_IPIER, &val); - xadc_write_reg(xadc, XADC_AXI_REG_IPISR, val & XADC_AXI_INT_EOS); + xadc_write_reg(xadc, XADC_AXI_REG_IPISR, XADC_AXI_INT_EOS); if (state) val |= XADC_AXI_INT_EOS; else
When enabling the trigger and unmasking the end-of-sequence (EOS) interrupt the EOS interrupt should be cleared from the status register. Otherwise it is possible that it was still set from a previous capture. If that is the case the interrupt would fire immediately even though no conversion has been done yet and stale data is being read from the device. The old code only clears the interrupt if the interrupt was previously unmasked. Which does not make much sense since the interrupt is always masked at this point and in addition masking the interrupt does not clear the interrupt from the status register. So the clearing needs to be done unconditionally. Signed-off-by: Lars-Peter Clausen <lars@metafoo.de> --- drivers/iio/adc/xilinx-xadc-core.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-)