staging: comedi: pcl726: tidy up pcl726_ao_insn()

[firefly-linux-kernel-4.4.55.git] / drivers / staging / comedi / drivers / pcl726.c

diff --git a/drivers/staging/comedi/drivers/pcl726.c b/drivers/staging/comedi/drivers/pcl726.c
index 17a4095be11b02d1439675312bec0e1744c8221f..fa14f3e90f8a08d0eb7788df96115dc66d6428ef 100644 (file)
--- a/drivers/staging/comedi/drivers/pcl726.c
+++ b/drivers/staging/comedi/drivers/pcl726.c
@@ -71,8 +71,8 @@ Interrupts are not supported.
 #define PCL727_SIZE 32
 #define PCL728_SIZE 8
 
-#define PCL726_DAC0_HI 0
-#define PCL726_DAC0_LO 1
+#define PCL726_AO_MSB_REG(x)   (0x00 + ((x) * 2))
+#define PCL726_AO_LSB_REG(x)   (0x01 + ((x) * 2))
 
 #define PCL726_DO_HI 12
 #define PCL726_DO_LO 13
@@ -187,31 +187,31 @@ struct pcl726_private {
        unsigned int ao_readback[12];
 };
 
-static int pcl726_ao_insn(struct comedi_device *dev, struct comedi_subdevice *s,
-                         struct comedi_insn *insn, unsigned int *data)
+static int pcl726_ao_insn_write(struct comedi_device *dev,
+                               struct comedi_subdevice *s,
+                               struct comedi_insn *insn,
+                               unsigned int *data)
 {
        struct pcl726_private *devpriv = dev->private;
        unsigned int chan = CR_CHAN(insn->chanspec);
        unsigned int range = CR_RANGE(insn->chanspec);
-       int hi, lo;
-       int n;
+       unsigned int val;
+       int i;
+
+       for (i = 0; i < insn->n; i++) {
+               val = data[i];
+               devpriv->ao_readback[chan] = val;
 
-       for (n = 0; n < insn->n; n++) {
-               lo = data[n] & 0xff;
-               hi = (data[n] >> 8) & 0xf;
+               /* bipolar data to the DAC is two's complement */
                if (comedi_chan_range_is_bipolar(s, chan, range))
-                       hi ^= 0x8;
-               /*
-                * the programming info did not say which order
-                * to write bytes.  switch the order of the next
-                * two lines if you get glitches.
-                */
-               outb(hi, dev->iobase + PCL726_DAC0_HI + 2 * chan);
-               outb(lo, dev->iobase + PCL726_DAC0_LO + 2 * chan);
-               devpriv->ao_readback[chan] = data[n];
+                       val = comedi_offset_munge(s, val);
+
+               /* order is important, MSB then LSB */
+               outb((val >> 8) & 0xff, dev->iobase + PCL726_AO_MSB_REG(chan));
+               outb(val & 0xff, dev->iobase + PCL726_AO_LSB_REG(chan));
        }
 
-       return n;
+       return insn->n;
 }
 
 static int pcl726_ao_insn_read(struct comedi_device *dev,
@@ -322,7 +322,7 @@ static int pcl726_attach(struct comedi_device *dev, struct comedi_devconfig *it)
        s->n_chan = board->n_aochan;
        s->maxdata = 0xfff;
        s->len_chanlist = 1;
-       s->insn_write = pcl726_ao_insn;
+       s->insn_write = pcl726_ao_insn_write;
        s->insn_read = pcl726_ao_insn_read;
        s->range_table_list = devpriv->rangelist;
        for (i = 0; i < board->n_aochan; i++) {