Commit 12700571 authored by H Hartley Sweeten's avatar H Hartley Sweeten Committed by Greg Kroah-Hartman
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staging: comedi: pcl818: 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 pcl818_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 db0446d0

drivers/staging/comedi/drivers/pcl818.c

+7 −12
Original line number Diff line number Diff line
@@ -547,21 +547,16 @@ static irqreturn_t interrupt_pcl818_ai_mode13_int(int irq, void *d) 
	struct comedi_subdevice *s = dev->read_subdev;

	struct comedi_cmd *cmd = &s->async->cmd;

	unsigned int chan;

	int timeout = 50;	/* wait max 50us */



	while (timeout--) {

		if (inb(dev->iobase + PCL818_STATUS) & 0x10)

			goto conv_finish;

		udelay(1);

	}

	if (pcl818_ai_eoc(dev, s, NULL, 0)) {

		outb(0, dev->iobase + PCL818_STATUS);	/* clear INT request */

		comedi_error(dev, "A/D mode1/3 IRQ without DRDY!");

		s->cancel(dev, s);

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

		comedi_event(dev, s);

		return IRQ_HANDLED;

	}



conv_finish:

	comedi_buf_put(s->async, pcl818_ai_get_sample(dev, s, &chan));

	outb(0, dev->iobase + PCL818_CLRINT);	/* clear INT request */