staging: comedi: adv_pci1710: fix ai (*insn_read)

An (*insn_read) can only happen if the subdevice is in a non-busy state,
i.e. an async command is not running. The board reset and subdevice
(*cancel) will ensure that the control bits (devpriv->ctrl) are already
cleared.

The (*insn_read) only needs to enable the software trigger before reading
samples. It should also disable the software trigger when done. Fix the
(*insn_read) to do this.

For aesthetics, rename the function so it has namespace associated with
the driver.
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/adv_pci1710.c

@@ -325,7 +325,7 @@ static int pci171x_ai_read_sample(struct comedi_device *dev,
 	return 0;
 }
 
-static int pci171x_ai_insn_read(struct comedi_device *dev,
+static int pci1710_ai_insn_read(struct comedi_device *dev,
 				struct comedi_subdevice *s,
 				struct comedi_insn *insn,
 				unsigned int *data)
@@ -334,9 +334,10 @@ static int pci171x_ai_insn_read(struct comedi_device *dev,
 	int ret = 0;
 	int i;
 
-	devpriv->ctrl &= PCI171X_CTRL_CNT0;
-	devpriv->ctrl |= PCI171X_CTRL_SW;	/*  set software trigger */
+	/* enable software trigger */
+	devpriv->ctrl |= PCI171X_CTRL_SW;
 	outw(devpriv->ctrl, dev->iobase + PCI171X_CTRL_REG);
+
 	outb(0, dev->iobase + PCI171X_CLRFIFO_REG);
 	outb(0, dev->iobase + PCI171X_CLRINT_REG);
 
@@ -359,6 +360,10 @@ static int pci171x_ai_insn_read(struct comedi_device *dev,
 		data[i] = val;
 	}
 
+	/* disable software trigger */
+	devpriv->ctrl &= ~PCI171X_CTRL_SW;
+	outw(devpriv->ctrl, dev->iobase + PCI171X_CTRL_REG);
+
 	outb(0, dev->iobase + PCI171X_CLRFIFO_REG);
 	outb(0, dev->iobase + PCI171X_CLRINT_REG);
 
@@ -802,7 +807,7 @@ static int pci1710_auto_attach(struct comedi_device *dev,
 	s->n_chan	= board->is_pci1713 ? 32 : 16;
 	s->maxdata	= 0x0fff;
 	s->range_table	= board->ai_range;
-	s->insn_read	= pci171x_ai_insn_read;
+	s->insn_read	= pci1710_ai_insn_read;
 	if (dev->irq) {
 		dev->read_subdev = s;
 		s->subdev_flags	|= SDF_CMD_READ;