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staging: comedi: pcl818: introduce pcl818_ai_get_sample()

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Introduce a helper function to read the 12-bit analog input data
sample and optionally return the channel that the sample was for.
The channel is only used in the interrupt routine to check for
dropped samples.

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 2014-02-17 14:27:16 -07:00 • committed by Greg Kroah-Hartman
parent 66581ca576
commit 8fc9f652ab
1 changed files with 21 additions and 9 deletions
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30
drivers/staging/comedi/drivers/pcl818.c
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@ -372,6 +372,21 @@ static int pcl818_ai_cancel(struct comedi_device *dev,
static void start_pacer(struct comedi_device *dev, int mode,
unsigned int divisor1, unsigned int divisor2);
static unsigned int pcl818_ai_get_sample(struct comedi_device *dev,
struct comedi_subdevice *s,
unsigned int *chan)
{
unsigned int val;
val = inb(dev->iobase + PCL818_AD_HI) << 8;
val |= inb(dev->iobase + PCL818_AD_LO);
if (chan)
*chan = val & 0xf;
return (val >> 4) & s->maxdata;
}
static int pcl818_ai_eoc(struct comedi_device *dev,
struct comedi_subdevice *s,
struct comedi_insn *insn,
@ -416,8 +431,7 @@ static int pcl818_ai_insn_read(struct comedi_device *dev,
return ret;
}
data[n] = ((inb(dev->iobase + PCL818_AD_HI) << 4) |
(inb(dev->iobase + PCL818_AD_LO) >> 4));
data[n] = pcl818_ai_get_sample(dev, s, NULL);
}
return n;
@ -502,7 +516,7 @@ static irqreturn_t interrupt_pcl818_ai_mode13_int(int irq, void *d)
struct comedi_device *dev = d;
struct pcl818_private *devpriv = dev->private;
struct comedi_subdevice *s = dev->read_subdev;
unsigned char low;
unsigned int chan;
int timeout = 50; /* wait max 50us */
while (timeout--) {
@ -518,14 +532,13 @@ static irqreturn_t interrupt_pcl818_ai_mode13_int(int irq, void *d)
return IRQ_HANDLED;
conv_finish:
low = inb(dev->iobase + PCL818_AD_LO);
comedi_buf_put(s->async, ((inb(dev->iobase + PCL818_AD_HI) << 4) | (low >> 4))); /* get one sample */
comedi_buf_put(s->async, pcl818_ai_get_sample(dev, s, &chan));
outb(0, dev->iobase + PCL818_CLRINT); /* clear INT request */
if ((low & 0xf) != devpriv->act_chanlist[devpriv->act_chanlist_pos]) { /* dropout! */
if (chan != devpriv->act_chanlist[devpriv->act_chanlist_pos]) {
dev_dbg(dev->class_dev,
"A/D mode1/3 IRQ - channel dropout %x!=%x !\n",
(low & 0xf),
chan,
devpriv->act_chanlist[devpriv->act_chanlist_pos]);
pcl818_ai_cancel(dev, s);
s->async->events |= COMEDI_CB_EOA | COMEDI_CB_ERROR;
@ -1166,8 +1179,7 @@ static int pcl818_ai_cancel(struct comedi_device *dev,
udelay(1);
start_pacer(dev, -1, 0, 0);
outb(0, dev->iobase + PCL818_AD_LO);
inb(dev->iobase + PCL818_AD_LO);
inb(dev->iobase + PCL818_AD_HI);
pcl818_ai_get_sample(dev, s, NULL);
outb(0, dev->iobase + PCL818_CLRINT); /* clear INT request */
outb(0, dev->iobase + PCL818_CONTROL); /* Stop A/D */
if (devpriv->usefifo) { /* FIFO shutdown */