staging: comedi: adv_pci1710: tidy up start_pacer()

For aesthetics, rename this function so it has namespace associated
with the driver.

Change the parameters to the function. The 'mode' is really a flag to
load the counters and the divisors can be found in the private data.

To clarify the code and remove the magic numbers, use the 8253.h
helpers to set the timer mode and load the counters.
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

@@ -73,6 +73,9 @@ Configuration options:
 #define PCI171x_DAREF	14	/* W:   D/A reference control */
 #define PCI171x_DI	16	/* R:   digi inputs */
 #define PCI171x_DO	16	/* R:   digi inputs */
+
+#define PCI171X_TIMER_BASE	0x18
+
 #define PCI171x_CNT0	24	/* R/W: 8254 counter 0 */
 #define PCI171x_CNT1	26	/* R/W: 8254 counter 1 */
 #define PCI171x_CNT2	28	/* R/W: 8254 counter 2 */
@@ -567,20 +570,18 @@ static int pci171x_insn_bits_do(struct comedi_device *dev,
 	return insn->n;
 }
 
-/*
-==============================================================================
-*/
-static void start_pacer(struct comedi_device *dev, int mode,
-			unsigned int divisor1, unsigned int divisor2)
+static void pci171x_start_pacer(struct comedi_device *dev,
+				bool load_counters)
 {
-	outw(0xb4, dev->iobase + PCI171x_CNTCTRL);
-	outw(0x74, dev->iobase + PCI171x_CNTCTRL);
-
-	if (mode == 1) {
-		outw(divisor2 & 0xff, dev->iobase + PCI171x_CNT2);
-		outw((divisor2 >> 8) & 0xff, dev->iobase + PCI171x_CNT2);
-		outw(divisor1 & 0xff, dev->iobase + PCI171x_CNT1);
-		outw((divisor1 >> 8) & 0xff, dev->iobase + PCI171x_CNT1);
+	struct pci1710_private *devpriv = dev->private;
+	unsigned long timer_base = dev->iobase + PCI171X_TIMER_BASE;
+
+	i8254_set_mode(timer_base, 1, 2, I8254_MODE2 | I8254_BINARY);
+	i8254_set_mode(timer_base, 1, 1, I8254_MODE2 | I8254_BINARY);
+
+	if (load_counters) {
+		i8254_write(timer_base, 1, 2, devpriv->divisor2);
+		i8254_write(timer_base, 1, 1, devpriv->divisor1);
 	}
 }
 
@@ -723,7 +724,7 @@ static int pci171x_ai_cancel(struct comedi_device *dev,
 		devpriv->CntrlReg |= Control_SW;
 
 		outw(devpriv->CntrlReg, dev->iobase + PCI171x_CONTROL);	/*  reset any operations */
-		start_pacer(dev, -1, 0, 0);
+		pci171x_start_pacer(dev, false);
 		outb(0, dev->iobase + PCI171x_CLRFIFO);
 		outb(0, dev->iobase + PCI171x_CLRINT);
 		break;
@@ -941,8 +942,7 @@ static irqreturn_t interrupt_service_pci1710(int irq, void *d)
 		outb(0, dev->iobase + PCI171x_CLRINT);
 		outw(devpriv->ai_et_MuxVal, dev->iobase + PCI171x_MUX);
 		outw(devpriv->CntrlReg, dev->iobase + PCI171x_CONTROL);
-		/*  start pacer */
-		start_pacer(dev, 1, devpriv->divisor1, devpriv->divisor2);
+		pci171x_start_pacer(dev, true);
 		return IRQ_HANDLED;
 	}
 
@@ -959,7 +959,7 @@ static int pci171x_ai_cmd(struct comedi_device *dev, struct comedi_subdevice *s)
 	struct pci1710_private *devpriv = dev->private;
 	struct comedi_cmd *cmd = &s->async->cmd;
 
-	start_pacer(dev, -1, 0, 0);	/*  stop pacer */
+	pci171x_start_pacer(dev, false);
 
 	setup_channel_list(dev, s, cmd->chanlist, cmd->chanlist_len,
 			   devpriv->saved_seglen);
@@ -990,11 +990,8 @@ static int pci171x_ai_cmd(struct comedi_device *dev, struct comedi_subdevice *s)
 		}
 		outw(devpriv->CntrlReg, dev->iobase + PCI171x_CONTROL);
 
-		if (cmd->start_src == TRIG_NOW) {
-			/*  start pacer */
-			start_pacer(dev, 1,
-				    devpriv->divisor1, devpriv->divisor2);
-		}
+		if (cmd->start_src == TRIG_NOW)
+			pci171x_start_pacer(dev, true);
 	} else {	/* TRIG_EXT */
 		devpriv->CntrlReg |= Control_EXT | Control_IRQEN;
 		outw(devpriv->CntrlReg, dev->iobase + PCI171x_CONTROL);
@@ -1098,7 +1095,7 @@ static int pci171x_reset(struct comedi_device *dev)
 	outw(devpriv->CntrlReg, dev->iobase + PCI171x_CONTROL);	/*  reset any operations */
 	outb(0, dev->iobase + PCI171x_CLRFIFO);	/*  clear FIFO */
 	outb(0, dev->iobase + PCI171x_CLRINT);	/*  clear INT request */
-	start_pacer(dev, -1, 0, 0);	/*  stop 8254 */
+	pci171x_start_pacer(dev, false);
 	devpriv->da_ranges = 0;
 	if (this_board->n_aochan) {
 		outb(devpriv->da_ranges, dev->iobase + PCI171x_DAREF);	/*  set DACs to 0..5V */