evie/android_kernel_oneplus_msm8998
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staging: comedi: pcl812: interrupt handlers should not busywait

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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: H Hartley Sweeten <hsweeten@visionengravers.com>
Reviewed-by: Ian Abbott <abbotti@mev.co.uk>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
This commit is contained in:
H Hartley Sweeten 2014-03-04 11:29:32 -07:00 • committed by Greg Kroah-Hartman
parent 080ee8820d
commit db0446d0e2
1 changed files with 1 additions and 22 deletions
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23
drivers/staging/comedi/drivers/pcl812.c
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@ -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;