> -----Original Message----- > From: Jonathan Cameron [mailto:jic23@xxxxxxxxxx] > Sent: Tuesday, April 6, 2021 2:52 AM > To: Song Bao Hua (Barry Song) <song.bao.hua@xxxxxxxxxxxxx> > Cc: linux-iio@xxxxxxxxxxxxxxx; Jonathan Cameron <jonathan.cameron@xxxxxxxxxx>; > Lars-Peter Clausen <lars@xxxxxxxxxx>; Alexandru Ardelean > <ardeleanalex@xxxxxxxxx>; tiantao (H) <tiantao6@xxxxxxxxxxxxx> > Subject: Re: [PATCH 7/7] iio:adc:ad_sigma_delta: Use IRQF_NO_AUTOEN rather than > request and disable > > On Fri, 2 Apr 2021 20:30:17 +0000 > "Song Bao Hua (Barry Song)" <song.bao.hua@xxxxxxxxxxxxx> wrote: > > > > -----Original Message----- > > > From: Jonathan Cameron [mailto:jic23@xxxxxxxxxx] > > > Sent: Saturday, April 3, 2021 7:46 AM > > > To: linux-iio@xxxxxxxxxxxxxxx > > > Cc: Song Bao Hua (Barry Song) <song.bao.hua@xxxxxxxxxxxxx>; Jonathan Cameron > > > <jonathan.cameron@xxxxxxxxxx>; Lars-Peter Clausen <lars@xxxxxxxxxx>; > > > Alexandru Ardelean <ardeleanalex@xxxxxxxxx> > > > Subject: [PATCH 7/7] iio:adc:ad_sigma_delta: Use IRQF_NO_AUTOEN rather than > > > request and disable > > > > > > From: Jonathan Cameron <Jonathan.Cameron@xxxxxxxxxx> > > > > > > These devices are not able to mask the signal used as a data ready > > > interrupt. As such they previously requested the irq then immediately > > > disabled it. Now we can avoid the potential of a spurious interrupt > > > by avoiding the irq being auto enabled in the first place. > > > > > > I'm not sure how this code could have been called with the irq already > > > disabled, so I believe the conditional would always have been true and > > > have removed it. > > > > > > > If irq_dis is true, it seems the original code assumed interrupt was > > open. Now the code is moving to disable-irq for true irq_dis. For > > false irq_dis, this patch has no side effect so looks correct. > Hi Barry, > > As far as I can tell (and I looked closely :), at the point where > ad_sd_probe_trigger() can be called, irq_dis is always false, > so the original check is misleading by implying > otherwise. I didn't realize that. Thanks for clarification. > > Taken in isolation of what is visible in this patch I'd agree > the change you suggest makes sense, but I'd also like to clean > up the wrong impression the original check was giving. It is > also worth noting that ad_sigma_delta.h lists irq_dis as a > private member of the structure that should only be used in the > library (reducing chances of any drivers in future doing something > odd with it). > Yes. It makes sense. > The other checks on irq_dis look suspicious as well, but removing > those would rather spread the scope of this patch. > > As Lars has given an Reviewed-by and this is his code, I'm going > to press ahead with this as it stands. > > Applied to the togreg branch of iio.git and pushed out as testing > for the autobuilders to see if we missed anything. > > Thanks, > > Jonathan > > > > > A safer way might be as below? > > > > if(!sigma_delta->irq_dis) > > irq_flags = sigma_delta->info->irq_flags | IRQF_NO_AUTOEN; > > > > request_irq(irq_flags); > > > > sigma_delta->irq_dis = true; > > > > > Signed-off-by: Jonathan Cameron <Jonathan.Cameron@xxxxxxxxxx> > > > Cc: Lars-Peter Clausen <lars@xxxxxxxxxx> > > > Cc: Alexandru Ardelean <ardeleanalex@xxxxxxxxx> > > > --- > > > drivers/iio/adc/ad_sigma_delta.c | 7 ++----- > > > 1 file changed, 2 insertions(+), 5 deletions(-) > > > > > > diff --git a/drivers/iio/adc/ad_sigma_delta.c > > > b/drivers/iio/adc/ad_sigma_delta.c > > > index 9289812c0a94..e777ec718973 100644 > > > --- a/drivers/iio/adc/ad_sigma_delta.c > > > +++ b/drivers/iio/adc/ad_sigma_delta.c > > > @@ -485,18 +485,15 @@ static int ad_sd_probe_trigger(struct iio_dev > *indio_dev) > > > sigma_delta->trig->ops = &ad_sd_trigger_ops; > > > init_completion(&sigma_delta->completion); > > > > > > + sigma_delta->irq_dis = true; > > > ret = request_irq(sigma_delta->spi->irq, > > > ad_sd_data_rdy_trig_poll, > > > - sigma_delta->info->irq_flags, > > > + sigma_delta->info->irq_flags | IRQF_NO_AUTOEN, > > > indio_dev->name, > > > sigma_delta); > > > if (ret) > > > goto error_free_trig; > > > > > > - if (!sigma_delta->irq_dis) { > > > - sigma_delta->irq_dis = true; > > > - disable_irq_nosync(sigma_delta->spi->irq); > > > - } > > > iio_trigger_set_drvdata(sigma_delta->trig, sigma_delta); > > > > > > ret = iio_trigger_register(sigma_delta->trig); > > > -- > > > 2.31.1 > > Thanks Barry
