On Thu, 24 Jun 2021 13:13:47 +0200
Nicolas Saenz Julienne <nsaenzju@xxxxxxxxxx> wrote:
> Hi Andy, thanks for the review.
>
> On Thu, 2021-06-24 at 13:39 +0300, Andy Shevchenko wrote:
> > On Thu, Jun 24, 2021 at 1:01 PM Nicolas Saenz Julienne
> > <nsaenzju@xxxxxxxxxx> wrote:
> > >
> > > The atlas sensor driver currently registers a threaded IRQ handler whose
> > > sole responsibility is to trigger an irq_work which will in turn run
> > > iio_trigger_poll() in IRQ context.
> > >
> > > This seems overkill given the fact that there already was a opportunity
> >
> > an opportunity
>
> Thanks, noted.
>
> > > @@ -474,7 +465,7 @@ static irqreturn_t atlas_interrupt_handler(int irq, void *private)
> > > struct iio_dev *indio_dev = private;
> > > struct atlas_data *data = iio_priv(indio_dev);
> > >
> > > - irq_work_queue(&data->work);
> > > + iio_trigger_poll(data->trig);
> >
> > Have you considered dropping atlas_interrupt_trigger_ops() altogether?
>
> Not really, but it makes sense as a separate patch. I'll take care of it.
>
> >
> > > if (client->irq > 0) {
> > > /* interrupt pin toggles on new conversion */
> > > ret = devm_request_threaded_irq(&client->dev, client->irq,
> >
> > > - NULL, atlas_interrupt_handler,
> > > + atlas_interrupt_handler, NULL,
> >
> > So, you move it from threaded IRQ to be a hard IRQ handler (we have a
> > separate call for this).
>
> Noted.
>
> > Can you guarantee that handling of those events will be fast enough?
>
> Do you mean the events triggered in iio_trigger_poll()? If so the amount of
> time spent in IRQ context is going to be the same regardless of whether it's
> handled through atlas' IRQ or later in irq_work IPI (or softirq context on some
> weird platforms).
>
Hi Nicolas, Andy, Matt,
Just been checking patchwork for IIO and noted that this one is still outstanding.
My reading of above is that we kind of got to a conclusion - though I'd like
Matt to sanity check the patch (and maybe test it if he still has hardware for
this?)
We have a generic form of this handler that may let you drop the atlas_interrupt_handler()
function entirely iio_trigger_generic_data_rdy_poll().
https://elixir.bootlin.com/linux/latest/source/drivers/iio/industrialio-trigger.c#L182
Thanks,
Jonathan
