staging: comedi: pcl711: tidy up pcl711_ao_insn()

For aesthetics, rename this function to help with greps.

Introduce a helper function to write the values to the analog
output channel registers. Modify the defines for the D/A registers
to avoid the ? : tests based on the chan number.

Only the final value written needs to be saved for read back.

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 9b439cc..9e19fe9 100644 (file)
--- a/drivers/staging/comedi/drivers/pcl711.c
+++ b/drivers/staging/comedi/drivers/pcl711.c
@@ -70,13 +70,11 @@ supported.
 #define PCL711_CTR2            0x02
 #define PCL711_CTRCTL          0x03
 #define PCL711_AD_LO           0x04
-#define PCL711_DA0_LO          0x04
 #define PCL711_AD_HI           0x05
-#define PCL711_DA0_HI          0x05
+#define PCL711_AO_LSB_REG(x)   (0x04 + ((x) * 2))
+#define PCL711_AO_MSB_REG(x)   (0x05 + ((x) * 2))
 #define PCL711_DI_LO           0x06
-#define PCL711_DA1_LO          0x06
 #define PCL711_DI_HI           0x07
-#define PCL711_DA1_HI          0x07
 #define PCL711_CLRINTR         0x08
 #define PCL711_GAIN            0x09
 #define PCL711_MUX             0x0a
@@ -405,26 +403,30 @@ static int pcl711_ai_cmd(struct comedi_device *dev, struct comedi_subdevice *s)
        return 0;
 }
 
-/*
-   analog output
-*/
-static int pcl711_ao_insn(struct comedi_device *dev, struct comedi_subdevice *s,
-                         struct comedi_insn *insn, unsigned int *data)
+static void pcl711_ao_write(struct comedi_device *dev,
+                           unsigned int chan, unsigned int val)
 {
-       struct pcl711_private *devpriv = dev->private;
-       int n;
-       int chan = CR_CHAN(insn->chanspec);
+       outb(val & 0xff, dev->iobase + PCL711_AO_LSB_REG(chan));
+       outb((val >> 8) & 0xff, dev->iobase + PCL711_AO_MSB_REG(chan));
+}
 
-       for (n = 0; n < insn->n; n++) {
-               outb((data[n] & 0xff),
-                    dev->iobase + (chan ? PCL711_DA1_LO : PCL711_DA0_LO));
-               outb((data[n] >> 8),
-                    dev->iobase + (chan ? PCL711_DA1_HI : PCL711_DA0_HI));
+static int pcl711_ao_insn_write(struct comedi_device *dev,
+                               struct comedi_subdevice *s,
+                               struct comedi_insn *insn,
+                               unsigned int *data)
+{
+       struct pcl711_private *devpriv = dev->private;
+       unsigned int chan = CR_CHAN(insn->chanspec);
+       unsigned int val = devpriv->ao_readback[chan];
+       int i;
 
-               devpriv->ao_readback[chan] = data[n];
+       for (i = 0; i < insn->n; i++) {
+               val = data[i];
+               pcl711_ao_write(dev, chan, val);
        }
+       devpriv->ao_readback[chan] = val;
 
-       return n;
+       return insn->n;
 }
 
 static int pcl711_ao_insn_read(struct comedi_device *dev,
@@ -530,7 +532,7 @@ static int pcl711_attach(struct comedi_device *dev, struct comedi_devconfig *it)
        s->n_chan       = board->n_aochan;
        s->maxdata      = 0xfff;
        s->range_table  = &range_bipolar5;
-       s->insn_write   = pcl711_ao_insn;
+       s->insn_write   = pcl711_ao_insn_write;
        s->insn_read    = pcl711_ao_insn_read;
 
        /* Digital Input subdevice */
@@ -552,12 +554,8 @@ static int pcl711_attach(struct comedi_device *dev, struct comedi_devconfig *it)
        s->insn_bits    = pcl711_do_insn_bits;
 
        /* clear DAC */
-       outb(0, dev->iobase + PCL711_DA0_LO);
-       outb(0, dev->iobase + PCL711_DA0_HI);
-       outb(0, dev->iobase + PCL711_DA1_LO);
-       outb(0, dev->iobase + PCL711_DA1_HI);
-
-       printk(KERN_INFO "\n");
+       pcl711_ao_write(dev, 0, 0x0);
+       pcl711_ao_write(dev, 1, 0x0);
 
        return 0;
 }