Commit db0446d0 authored by H Hartley Sweeten's avatar H Hartley Sweeten Committed by Greg Kroah-Hartman
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staging: comedi: pcl812: interrupt handlers should not busywait 



The interrupt is only generated by the hardware at the completion of
an A/D conversion. Because of this the sanity check to make sure that
the A/D conversion is complete and data is available is probably
unnecessary but it doesn't hurt anything.

The busywait loop is a different issue. Interrupt routines should not
busywait. That's just mean...

Remove the bustwait and use pcl812_ai_eoc() to check for the end-of-
conversion.

Signed-off-by: default avatarH Hartley Sweeten <hsweeten@visionengravers.com>
Reviewed-by: default avatarIan Abbott <abbotti@mev.co.uk>
Signed-off-by: default avatarGreg Kroah-Hartman <gregkh@linuxfoundation.org>
parent 080ee882

drivers/staging/comedi/drivers/pcl812.c

+1 −22
Original line number Diff line number Diff line
@@ -887,8 +887,6 @@ static int pcl812_ai_cmd(struct comedi_device *dev, struct comedi_subdevice *s) 


static irqreturn_t interrupt_pcl812_ai_int(int irq, void *d)

{

	char err = 1;

	unsigned int timeout;

	struct comedi_device *dev = d;

	struct pcl812_private *devpriv = dev->private;

	struct comedi_subdevice *s = dev->read_subdev;
@@ -897,26 +895,7 @@ static irqreturn_t interrupt_pcl812_ai_int(int irq, void *d) 


	s->async->events = 0;



	timeout = 50;		/* wait max 50us, it must finish under 33us */

	if (s->maxdata > 0x0fff) {

		while (timeout--) {

			if (!(inb(dev->iobase + ACL8216_STATUS) & ACL8216_DRDY)) {

				err = 0;

				break;

			}

			udelay(1);

		}

	} else {

		while (timeout--) {

			if (!(inb(dev->iobase + PCL812_AD_HI) & PCL812_DRDY)) {

				err = 0;

				break;

			}

			udelay(1);

		}

	}



	if (err) {

	if (pcl812_ai_eoc(dev, s, NULL, 0)) {

		dev_dbg(dev->class_dev, "A/D cmd IRQ without DRDY!\n");

		s->cancel(dev, s);

		s->async->events |= COMEDI_CB_EOA | COMEDI_CB_ERROR;