staging: comedi: ii_pci20kc: save unmunged data for ao readback

The unmunged data should be saved for readback not the munged data.
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>

drivers/staging/comedi/drivers/ii_pci20kc.c

@@ -165,12 +165,14 @@ static int ii20k_ao_insn_write(struct comedi_device *dev,
 	struct ii20k_ao_private *ao_spriv = s->private;
 	void __iomem *iobase = ii20k_module_iobase(dev, s);
 	unsigned int chan = CR_CHAN(insn->chanspec);
-	unsigned int val = ao_spriv->last_data[chan];
+	unsigned int val;
 	int i;
 
 	for (i = 0; i < insn->n; i++) {
 		val = data[i];
 
+		ao_spriv->last_data[chan] = val;
+
 		/* munge data */
 		val += ((s->maxdata + 1) >> 1);
 		val &= s->maxdata;
@@ -180,8 +182,6 @@ static int ii20k_ao_insn_write(struct comedi_device *dev,
 		writeb(0x00, iobase + II20K_AO_STRB_REG(chan));
 	}
 
-	ao_spriv->last_data[chan] = val;
-
 	return insn->n;
 }