staging: comedi: adl_pci6208: cleanup pci6208_ao_winsn()

Use the defines for the register map to make the code a bit
clearer. Shorten or rename some of the local variables for
the same reason.

Only the last value written to the DAC needs to be cached in
the ao_readback variable.

Signed-off-by: H Hartley Sweeten <hsweeten@visionengravers.com>
Cc: Ian Abbott <abbotti@mev.co.uk>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

diff --git a/drivers/staging/comedi/drivers/adl_pci6208.c b/drivers/staging/comedi/drivers/adl_pci6208.c
index d15f0cb..7120878 100644 (file)
--- a/drivers/staging/comedi/drivers/adl_pci6208.c
+++ b/drivers/staging/comedi/drivers/adl_pci6208.c
@@ -82,21 +82,24 @@ static int pci6208_ao_winsn(struct comedi_device *dev,
                            struct comedi_insn *insn, unsigned int *data)
 {
        struct pci6208_private *devpriv = dev->private;
-       int i = 0, Data_Read;
-       unsigned short chan = CR_CHAN(insn->chanspec);
+       int chan = CR_CHAN(insn->chanspec);
        unsigned long invert = 1 << (16 - 1);
-       unsigned long out_value;
+       unsigned long value = 0;
+       unsigned short status;
+       int i;
 
        for (i = 0; i < insn->n; i++) {
-               out_value = data[i] ^ invert;
+               value = data[i] ^ invert;
+
                do {
-                       Data_Read = (inw(dev->iobase) & 1);
-               } while (Data_Read);
-               outw(out_value, dev->iobase + (0x02 * chan));
-               devpriv->ao_readback[chan] = out_value;
+                       status = inw(dev->iobase + PCI6208_AO_STATUS);
+               } while (status & PCI6208_AO_STATUS_DATA_SEND);
+
+               outw(value, dev->iobase + PCI6208_AO_CONTROL(chan));
        }
+       devpriv->ao_readback[chan] = value;
 
-       return i;
+       return insn->n;
 }
 
 static int pci6208_ao_rinsn(struct comedi_device *dev,