staging: comedi: pcl816: introduce pcl816_ai_get_sample()

Introduce a helper function to read the 14/16-bit analog input data
sample.

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 7e7c30247eefe2528f296b73c54d3dfc9ffc0423..6d3965bffdafbe511930b21d42f0d8b1ead8250d 100644 (file)
--- a/drivers/staging/comedi/drivers/pcl816.c
+++ b/drivers/staging/comedi/drivers/pcl816.c
@@ -165,6 +165,17 @@ static int pcl816_ai_cmdtest(struct comedi_device *dev,
                             struct comedi_cmd *cmd);
 static int pcl816_ai_cmd(struct comedi_device *dev, struct comedi_subdevice *s);
 
+static unsigned int pcl816_ai_get_sample(struct comedi_device *dev,
+                                        struct comedi_subdevice *s)
+{
+       unsigned int val;
+
+       val = inb(dev->iobase + PCL816_AD_HI) << 8;
+       val |= inb(dev->iobase + PCL816_AD_LO);
+
+       return val & s->maxdata;
+}
+
 static int pcl816_ai_eoc(struct comedi_device *dev,
                         struct comedi_subdevice *s,
                         struct comedi_insn *insn,
@@ -206,9 +217,8 @@ static int pcl816_ai_insn_read(struct comedi_device *dev,
                        return ret;
                }
 
-               /*  return read value */
-               data[n] = ((inb(dev->iobase + PCL816_AD_HI) << 8) |
-                         (inb(dev->iobase + PCL816_AD_LO)));
+               data[n] = pcl816_ai_get_sample(dev, s);
+
                /* clear INT (conversion end) flag */
                outb(0, dev->iobase + PCL816_CLRINT);
        }
@@ -225,7 +235,6 @@ static irqreturn_t interrupt_pcl816_ai_mode13_int(int irq, void *d)
        struct comedi_device *dev = d;
        struct pcl816_private *devpriv = dev->private;
        struct comedi_subdevice *s = dev->read_subdev;
-       unsigned char low, hi;
        int timeout = 50;       /* wait max 50us */
 
        while (timeout--) {
@@ -244,11 +253,7 @@ static irqreturn_t interrupt_pcl816_ai_mode13_int(int irq, void *d)
 
        }
 
-       /*  get the sample */
-       low = inb(dev->iobase + PCL816_AD_LO);
-       hi = inb(dev->iobase + PCL816_AD_HI);
-
-       comedi_buf_put(s->async, (hi << 8) | low);
+       comedi_buf_put(s->async, pcl816_ai_get_sample(dev, s));
 
        outb(0, dev->iobase + PCL816_CLRINT);   /* clear INT request */
 
@@ -655,8 +660,7 @@ static int pcl816_ai_cancel(struct comedi_device *dev,
                        outb(0xb0, dev->iobase + PCL816_CTRCTL);
                        outb(0x70, dev->iobase + PCL816_CTRCTL);
                        outb(0, dev->iobase + PCL816_AD_LO);
-                       inb(dev->iobase + PCL816_AD_LO);
-                       inb(dev->iobase + PCL816_AD_HI);
+                       pcl816_ai_get_sample(dev, s);
 
                        /* clear INT request */
                        outb(0, dev->iobase + PCL816_CLRINT);