On Tue, 25 Sep 2018 15:17:39 +0200
Ludovic Desroches <ludovic.desroches@xxxxxxxxxxxxx> wrote:
> On Mon, Sep 24, 2018 at 10:51:43AM +0300, Eugen Hristev wrote:
> > When doing simple conversions, the driver did not acknowledge the DRDY irq.
> > If this irq status is not acked, it will be left pending, and as soon as a
> > trigger is enabled, the irq handler will be called, it doesn't know why
> > this status has occurred because no channel is pending, and then it will go
> > int a irq loop and board will hang.
> > To avoid this situation, read the LCDR after a raw conversion is done.
> >
> > Fixes 0e589d5fb ("ARM: AT91: IIO: Add AT91 ADC driver.")
> > Cc: Maxime Ripard <maxime.ripard@xxxxxxxxxxx>
> > Signed-off-by: Eugen Hristev <eugen.hristev@xxxxxxxxxxxxx>
> Acked-by: Ludovic Desroches <ludovic.desroches@xxxxxxxxxxxxx>
Applied to the togreg branch of iio.git and marked for stable.
It's been broken long enough that I think it can wait for the merge window
coming in a few weeks time.
Thanks,
Jonathan
>
> > ---
> > Hello Jonathan,
> >
> > I moved this LCDR read/acknowledge into the IRQ handler after the conversion
> > value is being read.
> > Sorry about the noise to stable@vger, removed from message.
> >
> > Thanks,
> > Eugen
> >
> > drivers/iio/adc/at91_adc.c | 2 ++
> > 1 file changed, 2 insertions(+)
> >
> > diff --git a/drivers/iio/adc/at91_adc.c b/drivers/iio/adc/at91_adc.c
> > index 44b5168..e3be88e 100644
> > --- a/drivers/iio/adc/at91_adc.c
> > +++ b/drivers/iio/adc/at91_adc.c
> > @@ -279,6 +279,8 @@ static void handle_adc_eoc_trigger(int irq, struct iio_dev *idev)
> > iio_trigger_poll(idev->trig);
> > } else {
> > st->last_value = at91_adc_readl(st, AT91_ADC_CHAN(st, st->chnb));
> > + /* Needed to ACK the DRDY interruption */
> > + at91_adc_readl(st, AT91_ADC_LCDR);
> > st->done = true;
> > wake_up_interruptible(&st->wq_data_avail);
> > }
> > --
> > 2.7.4
> >
