staging: comedi: addi_apci_3xxx: remove 'b_SingleDiff' private data

The analog reference desired for the acquisition is stored in the
insn->chanspec that is passed to the (*insn_read) function. There is
no need to use a private data variable to hold the desired analog
reference that is set in the (*insn_config).
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/addi-data/hwdrv_apci3xxx.c

@@ -41,14 +41,10 @@ static int apci3xxx_ai_configure(struct comedi_device *dev,
 {
 	const struct apci3xxx_boardinfo *board = comedi_board(dev);
 	struct apci3xxx_private *devpriv = dev->private;
-	unsigned int aref_mode = data[1];
 	unsigned int time_base = data[2];
 	unsigned int reload_time = data[3];
 	unsigned int acq_ns;
 
-	if (aref_mode != 0 && aref_mode != 1)
-		return -EINVAL;
-
 	if (time_base > 2)
 		return -EINVAL;
 
@@ -80,7 +76,6 @@ static int apci3xxx_ai_configure(struct comedi_device *dev,
 
 	devpriv->ui_EocEosConversionTime = reload_time;
 	devpriv->b_EocEosConversionTimeBase = time_base;
-	devpriv->b_SingelDiff = aref_mode;
 
 	/* Set the convert timing unit */
 	writel(time_base, devpriv->mmio + 36);
@@ -116,6 +111,7 @@ static int apci3xxx_ai_insn_read(struct comedi_device *dev,
 	struct apci3xxx_private *devpriv = dev->private;
 	unsigned int chan = CR_CHAN(insn->chanspec);
 	unsigned int range = CR_RANGE(insn->chanspec);
+	unsigned int aref = CR_AREF(insn->chanspec);
 	unsigned char use_interrupt = 0;	/* FIXME: use interrupts */
 	unsigned int delay_mode;
 	unsigned int val;
@@ -139,7 +135,7 @@ static int apci3xxx_ai_insn_read(struct comedi_device *dev,
 
 	/* Make the configuration */
 	val = (range & 3) | ((range >> 2) << 6) |
-	      (devpriv->b_SingelDiff << 7);
+	      ((aref == AREF_DIFF) << 7);
 	writel(val, devpriv->mmio + 0);
 
 	/* Channel selection */

drivers/staging/comedi/drivers/addi_apci_3xxx.c

@@ -356,7 +356,6 @@ struct apci3xxx_private {
 	unsigned char b_EocEosInterrupt;
 	unsigned int ui_EocEosConversionTime;
 	unsigned char b_EocEosConversionTimeBase;
-	unsigned char b_SingelDiff;
 };
 
 #include "addi-data/hwdrv_apci3xxx.c"
@@ -611,9 +610,6 @@ static int apci3xxx_auto_attach(struct comedi_device *dev,
 		s->insn_config = apci3xxx_ai_insn_config;
 		s->insn_read = apci3xxx_ai_insn_read;
 
-		if ((board->ai_subdev_flags & (SDF_COMMON | SDF_GROUND)) == 0)
-			devpriv->b_SingelDiff = 1;
-
 	} else {
 		s->type = COMEDI_SUBD_UNUSED;
 	}