staging: comedi: pcmmio: move ao shadow data to device private data

There is only one ai subdevice in this driver so there is no reason
to hold the last sample written to each channel in the subdevice
private data. Move the data into the device private data,

This gets some of the data out of the subdevice private data union
and removes some of the uses of the ugly 'subpriv' macro.
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/pcmmio.c

@@ -231,10 +231,6 @@ struct pcmmio_subdev_private {
 				spinlock_t spinlock;
 			} intr;
 		} dio;
-		struct {
-			/* the last unsigned int data written */
-			unsigned int shadow_samples[8];
-		} ao;
 	};
 };
 
@@ -256,6 +252,7 @@ struct pcmmio_private {
 		spinlock_t spinlock;
 	} asics[MAX_ASICS];
 	struct pcmmio_subdev_private *sprivs;
+	unsigned int ao_readback[8];
 };
 
 #define subpriv ((struct pcmmio_subdev_private *)s->private)
@@ -857,11 +854,13 @@ static int pcmmio_ai_insn_read(struct comedi_device *dev,
 static int ao_rinsn(struct comedi_device *dev, struct comedi_subdevice *s,
 		    struct comedi_insn *insn, unsigned int *data)
 {
+	struct pcmmio_private *devpriv = dev->private;
 	int n;
+
 	for (n = 0; n < insn->n; n++) {
 		unsigned chan = CR_CHAN(insn->chanspec);
 		if (chan < s->n_chan)
-			data[n] = subpriv->ao.shadow_samples[chan];
+			data[n] = devpriv->ao_readback[chan];
 	}
 	return n;
 }
@@ -887,6 +886,7 @@ static int wait_dac_ready(unsigned long iobase)
 static int ao_winsn(struct comedi_device *dev, struct comedi_subdevice *s,
 		    struct comedi_insn *insn, unsigned int *data)
 {
+	struct pcmmio_private *devpriv = dev->private;
 	int n;
 	unsigned iobase = subpriv->iobase, iooffset = 0;
 
@@ -925,7 +925,7 @@ static int ao_winsn(struct comedi_device *dev, struct comedi_subdevice *s,
 			wait_dac_ready(iobase + iooffset);
 
 			/* save to shadow register for ao_rinsn */
-			subpriv->ao.shadow_samples[chan] = data[n];
+			devpriv->ao_readback[chan] = data[n];
 		}
 	}
 	return n;