staging: comedi: pcl711: introduce pcl711_ai_get_sample()

Introduce a helper function to read the analog input data from the
hardware.

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/pcl711.c b/drivers/staging/comedi/drivers/pcl711.c
index 3a2e5f16d28408136a0be2cb54cbc80e056ec907..255cfd16aa1cb2cb5a8bd83f948c1f5fe174e364 100644 (file)
--- a/drivers/staging/comedi/drivers/pcl711.c
+++ b/drivers/staging/comedi/drivers/pcl711.c
@@ -69,8 +69,8 @@ supported.
 #define PCL711_CTR1            0x01
 #define PCL711_CTR2            0x02
 #define PCL711_CTRCTL          0x03
-#define PCL711_AD_LO           0x04
-#define PCL711_AD_HI           0x05
+#define PCL711_AI_LSB_REG      0x04
+#define PCL711_AI_MSB_REG      0x05
 #define PCL711_AO_LSB_REG(x)   (0x04 + ((x) * 2))
 #define PCL711_AO_MSB_REG(x)   (0x05 + ((x) * 2))
 #define PCL711_DI_LO           0x06
@@ -185,25 +185,33 @@ struct pcl711_private {
        unsigned int divisor2;
 };
 
+static unsigned int pcl711_ai_get_sample(struct comedi_device *dev,
+                                        struct comedi_subdevice *s)
+{
+       unsigned int val;
+
+       val = inb(dev->iobase + PCL711_AI_MSB_REG) << 8;
+       val |= inb(dev->iobase + PCL711_AI_LSB_REG);
+
+       return val & s->maxdata;
+}
+
 static irqreturn_t pcl711_interrupt(int irq, void *d)
 {
-       int lo, hi;
-       int data;
        struct comedi_device *dev = d;
        const struct pcl711_board *board = comedi_board(dev);
        struct pcl711_private *devpriv = dev->private;
        struct comedi_subdevice *s = &dev->subdevices[0];
+       unsigned int data;
 
        if (!dev->attached) {
                comedi_error(dev, "spurious interrupt");
                return IRQ_HANDLED;
        }
 
-       hi = inb(dev->iobase + PCL711_AD_HI);
-       lo = inb(dev->iobase + PCL711_AD_LO);
-       outb(0, dev->iobase + PCL711_CLRINTR);
+       data = pcl711_ai_get_sample(dev, s);
 
-       data = (hi << 8) | lo;
+       outb(0, dev->iobase + PCL711_CLRINTR);
 
        /* FIXME! Nothing else sets ntrig! */
        if (!(--devpriv->ntrig)) {
@@ -251,7 +259,7 @@ static int pcl711_ai_insn(struct comedi_device *dev, struct comedi_subdevice *s,
 {
        const struct pcl711_board *board = comedi_board(dev);
        int i, n;
-       int hi, lo;
+       int hi;
 
        pcl711_set_changain(dev, insn->chanspec);
 
@@ -267,7 +275,7 @@ static int pcl711_ai_insn(struct comedi_device *dev, struct comedi_subdevice *s,
 
                i = PCL711_TIMEOUT;
                while (--i) {
-                       hi = inb(dev->iobase + PCL711_AD_HI);
+                       hi = inb(dev->iobase + PCL711_AI_MSB_REG);
                        if (!(hi & PCL711_DRDY))
                                goto ok;
                        udelay(1);
@@ -276,9 +284,7 @@ static int pcl711_ai_insn(struct comedi_device *dev, struct comedi_subdevice *s,
                return -ETIME;
 
 ok:
-               lo = inb(dev->iobase + PCL711_AD_LO);
-
-               data[n] = ((hi & 0xf) << 8) | lo;
+               data[n] = pcl711_ai_get_sample(dev, s);
        }
 
        return n;