Re: [Uclinux-dist-devel] [PATCH v2] mfd: ADP5520 Multifunction LCDBacklight and Keypad Input Device Driver

Samuel Ortiz
2009-10-02T14:03:30Z

Hi Michael,

On Fri, Oct 02, 2009 at 02:48:27PM +0100, Hennerich, Michael wrote:
> >From: uclinux-dist-devel-bounces@blackfin.uclinux.org
> [mailto:uclinux-dist-devel-
> >bounces@blackfin.uclinux.org] On Behalf Of Hennerich, Michael
> >Device Driver
> >
> >Hi Samuel,
> >
> >>From: Samuel Ortiz [mailto:sameo@linux.intel.com]
> >>Hi Mike,
> >>
> >>Some comments on this patch:
> >>
> >>On Wed, Sep 23, 2009 at 01:11:04AM -0400, Mike Frysinger wrote:
> >>> +static irqreturn_t adp5520_irq_handler(int irq, void *data)
> >>> +{
> >>> + struct adp5520_chip *chip = data;
> >>> +
> >>> + disable_irq_nosync(irq);
> >>> + schedule_work(&chip->irq_work);
> >>Have you considered using a threaded irq handler here ?
> >
> >The Linux version I developed this driver on didn't feature threaded
> irq
> >handlers.
> >But thanks I'm going to take a look here.
>
> Hi Samuel,
>
> Well the threaded irq handlers are no option here, since we use a Level
> Sensitive Interrupt.
> The work queue here is to schedule the main irq handler outside hardirq
> context.
> I2C can't we invoked form none sleepy context, so we can't clear the
> interrupt.
> This will cause that we execute the hardirq over and over again,
> preventing the irq thread to be run.
>
> The threaded irqs with its current implementation also doesn't allow me
> to disable the irq in the hardirq handler.
Ok, that's the piece I missed. Thanks for the clarification.

> There have been some discussions about this on lkml recently.
> Until there is a way to workaround this issue (handle_level_oneshot_irq,
> etc.),
> I like to stick with:
Fine with me, yes.

Cheers,
Samuel.

> >>> + disable_irq_nosync(irq);
> >>> + schedule_work(&chip->irq_work);
>
> Best regards,
> Michael
>

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