| Message ID | 1537775504-7981-1-git-send-email-eugen.hristev@microchip.com (mailing list archive) |
|---|---|
| State | New, archived |
| Headers | show |
| Series | [v2,1/2] iio: adc: at91: fix acking DRDY irq on simple conversions | expand |
On Mon, 24 Sep 2018 10:51:43 +0300 Eugen Hristev <eugen.hristev@microchip.com> 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@bootlin.com> > Signed-off-by: Eugen Hristev <eugen.hristev@microchip.com> > --- > Hello Jonathan, > > I moved this LCDR read/acknowledge into the IRQ handler after the conversion > value is being read. Ah.. This all makes more sense now. I'd misunderstood originally and thought we were looking at a read raw that wasn't using the interrupt at all. Sorry about that. However, mostly by coincidence (given I misread the code) I think this is a neater way to do this than the previous option as it puts it near the actual read. Given Maxime is the author of this one though I'd like to leave it on the list a little longer before applying. At this stage in the cycle I'll probably just queue it up for the next merge window anyway (marked for stable). It's not exactly a new bug after all. Thanks, Jonathan > 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); > }
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@bootlin.com> > Signed-off-by: Eugen Hristev <eugen.hristev@microchip.com> Acked-by: Ludovic Desroches <ludovic.desroches@microchip.com> > --- > 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 >
On Tue, 25 Sep 2018 15:17:39 +0200 Ludovic Desroches <ludovic.desroches@microchip.com> 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@bootlin.com> > > Signed-off-by: Eugen Hristev <eugen.hristev@microchip.com> > Acked-by: Ludovic Desroches <ludovic.desroches@microchip.com> 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 > >
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); }
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@bootlin.com> Signed-off-by: Eugen Hristev <eugen.hristev@microchip.com> --- 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(+)