staging: comedi: rti802: tidy up rti802_ao_insn_write()

Use comedi_offset_munge() to handle munging the offset binary to two's
complement.

Tidy up the function a bit.

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/rti802.c b/drivers/staging/comedi/drivers/rti802.c
index c1f4b3b71542ea2a4b61ed30b59edcbd4e37f58c..d20eb629f9f93153c1a7b9c535a30167bbcfc9ba 100644 (file)
--- a/drivers/staging/comedi/drivers/rti802.c
+++ b/drivers/staging/comedi/drivers/rti802.c
@@ -64,21 +64,30 @@ static int rti802_ao_insn_read(struct comedi_device *dev,
 
 static int rti802_ao_insn_write(struct comedi_device *dev,
                                struct comedi_subdevice *s,
-                               struct comedi_insn *insn, unsigned int *data)
+                               struct comedi_insn *insn,
+                               unsigned int *data)
 {
        struct rti802_private *devpriv = dev->private;
-       int i, d;
-       int chan = CR_CHAN(insn->chanspec);
+       unsigned int chan = CR_CHAN(insn->chanspec);
+       unsigned int val;
+       int i;
+
+       outb(chan, dev->iobase + RTI802_SELECT);
 
        for (i = 0; i < insn->n; i++) {
-               d = devpriv->ao_readback[chan] = data[i];
+               val = data[i];
+
+               devpriv->ao_readback[chan] = val;
+
+               /* munge offset binary to two's complement if needed */
                if (devpriv->dac_coding[chan] == dac_2comp)
-                       d ^= 0x800;
-               outb(chan, dev->iobase + RTI802_SELECT);
-               outb(d & 0xff, dev->iobase + RTI802_DATALOW);
-               outb(d >> 8, dev->iobase + RTI802_DATAHIGH);
+                       val = comedi_offset_munge(s, val);
+
+               outb(val & 0xff, dev->iobase + RTI802_DATALOW);
+               outb((val >> 8) & 0xff, dev->iobase + RTI802_DATAHIGH);
        }
-       return i;
+
+       return insn->n;
 }
 
 static int rti802_attach(struct comedi_device *dev, struct comedi_devconfig *it)