staging: comedi: pcl816: tidy up the analog input (*insn_read)

For aesthetics, move this function out of the async command support
code.

For safety, the INT request (end-of-conversion flag) should be cleared
before doing each conversion and after the final data sample is read.
This driver does that but it's a bit awkward with the initial clear being
outside the for loop that reads the samples.

Refactor the function a bit so it's more like the pcl818 driver and we
can use common code to clear the flag for a timeout and after the last
sample.

Do a bit of other tidying up during the move.

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>

diff --git a/drivers/staging/comedi/drivers/pcl816.c b/drivers/staging/comedi/drivers/pcl816.c
index 2487e4448fc443e4a4549022c646d0a2befe58fa..e9795106b8485ca4c833baec12213b51c9a4bb51 100644 (file)
--- a/drivers/staging/comedi/drivers/pcl816.c
+++ b/drivers/staging/comedi/drivers/pcl816.c
@@ -232,42 +232,6 @@ static int pcl816_ai_eoc(struct comedi_device *dev,
        return -EBUSY;
 }
 
-static int pcl816_ai_insn_read(struct comedi_device *dev,
-                              struct comedi_subdevice *s,
-                              struct comedi_insn *insn, unsigned int *data)
-{
-       int ret;
-       int n;
-
-       /*  software trigger, DMA and INT off */
-       outb(0, dev->iobase + PCL816_CONTROL);
-       /*  clear INT (conversion end) flag */
-       outb(0, dev->iobase + PCL816_CLRINT);
-
-       /*  Set the input channel */
-       outb(CR_CHAN(insn->chanspec) & 0xf, dev->iobase + PCL816_MUX);
-       /* select gain */
-       outb(CR_RANGE(insn->chanspec), dev->iobase + PCL816_RANGE);
-
-       for (n = 0; n < insn->n; n++) {
-
-               outb(0, dev->iobase + PCL816_AD_LO);    /* start conversion */
-
-               ret = comedi_timeout(dev, s, insn, pcl816_ai_eoc, 0);
-               if (ret) {
-                       /* clear INT (conversion end) flag */
-                       outb(0, dev->iobase + PCL816_CLRINT);
-                       return ret;
-               }
-
-               data[n] = pcl816_ai_get_sample(dev, s);
-
-               /* clear INT (conversion end) flag */
-               outb(0, dev->iobase + PCL816_CLRINT);
-       }
-       return n;
-}
-
 static bool pcl816_ai_next_chan(struct comedi_device *dev,
                                struct comedi_subdevice *s)
 {
@@ -630,6 +594,42 @@ setup_channel_list(struct comedi_device *dev,
             dev->iobase + PCL816_MUX);
 }
 
+static int pcl816_ai_insn_read(struct comedi_device *dev,
+                              struct comedi_subdevice *s,
+                              struct comedi_insn *insn,
+                              unsigned int *data)
+{
+       unsigned int chan = CR_CHAN(insn->chanspec);
+       unsigned int range = CR_RANGE(insn->chanspec);
+       int ret = 0;
+       int i;
+
+       /*  software trigger, DMA and INT off */
+       outb(0, dev->iobase + PCL816_CONTROL);
+
+       /*  Set the input channel */
+       outb(chan, dev->iobase + PCL816_MUX);
+       /* select gain */
+       outb(range, dev->iobase + PCL816_RANGE);
+
+       for (i = 0; i < insn->n; i++) {
+               /* clear INT (conversion end) flag */
+               outb(0, dev->iobase + PCL816_CLRINT);
+               /* start conversion */
+               outb(0, dev->iobase + PCL816_AD_LO);
+
+               ret = comedi_timeout(dev, s, insn, pcl816_ai_eoc, 0);
+               if (ret)
+                       break;
+
+               data[i] = pcl816_ai_get_sample(dev, s);
+       }
+       /* clear INT (conversion end) flag */
+       outb(0, dev->iobase + PCL816_CLRINT);
+
+       return ret ? ret : insn->n;
+}
+
 static int pcl816_di_insn_bits(struct comedi_device *dev,
                               struct comedi_subdevice *s,
                               struct comedi_insn *insn,