From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail.kernel.org ([198.145.29.99]:41940 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1727872AbeI2R7S (ORCPT ); Sat, 29 Sep 2018 13:59:18 -0400 Date: Sat, 29 Sep 2018 12:31:07 +0100 From: Jonathan Cameron To: Ludovic Desroches Cc: Eugen Hristev , , , , , Maxime Ripard Subject: Re: [PATCH v2 1/2] iio: adc: at91: fix acking DRDY irq on simple conversions Message-ID: <20180929123107.0d0053e3@archlinux> In-Reply-To: <20180925131739.2nuoelhqmkszamqo@M43218.corp.atmel.com> References: <1537775504-7981-1-git-send-email-eugen.hristev@microchip.com> <20180925131739.2nuoelhqmkszamqo@M43218.corp.atmel.com> MIME-Version: 1.0 Content-Type: text/plain; charset=US-ASCII Sender: linux-iio-owner@vger.kernel.org List-Id: linux-iio@vger.kernel.org On Tue, 25 Sep 2018 15:17:39 +0200 Ludovic Desroches 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 > > Signed-off-by: Eugen Hristev > Acked-by: Ludovic Desroches 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 > >