staging: comedi: addi_apci_3120: tidy up devpriv->mode in apci3120_ai_cmd()

There is no reason for the separate updates of the mode register in this
function. Refactor the code so that the mode register is only updated at
the end of the function after all the necessary bits have been set.
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_apci3120.c

@@ -373,8 +373,9 @@ static int apci3120_ai_cmd(struct comedi_device *dev,
 	struct comedi_cmd *cmd = &s->async->cmd;
 	unsigned int divisor;
 
-	devpriv->mode = 0;
-	outb(devpriv->mode, dev->iobase + APCI3120_MODE_REG);
+	/* set default mode bits */
+	devpriv->mode = APCI3120_MODE_TIMER2_CLK_OSC |
+			APCI3120_MODE_TIMER2_AS_TIMER;
 
 	/* Clear Timer Write TC int */
 	outl(APCI3120_CLEAR_WRITE_TC_INT,
@@ -415,11 +416,9 @@ static int apci3120_ai_cmd(struct comedi_device *dev,
 		devpriv->b_InterruptMode = APCI3120_DMA_MODE;
 		apci3120_setup_dma(dev, s);
 	} else {
-		/*  disable EOC and enable EOS */
 		devpriv->b_InterruptMode = APCI3120_EOS_MODE;
 
 		devpriv->mode |= APCI3120_MODE_EOS_IRQ_ENA;
-		outb(devpriv->mode, dev->iobase + APCI3120_MODE_REG);
 
 		if (cmd->stop_src == TRIG_COUNT) {
 			/*
@@ -439,13 +438,15 @@ static int apci3120_ai_cmd(struct comedi_device *dev,
 			devpriv->mode |= APCI3120_MODE_TIMER2_AS_COUNTER |
 					 APCI3120_MODE_TIMER2_CLK_EOS |
 					 APCI3120_MODE_TIMER2_IRQ_ENA;
-			outb(devpriv->mode, dev->iobase + APCI3120_MODE_REG);
 
 			devpriv->b_Timer2Mode = APCI3120_COUNTER;
 			devpriv->b_Timer2Interrupt = 1;
 		}
 	}
 
+	/* set mode to enable acquisition */
+	outb(devpriv->mode, dev->iobase + APCI3120_MODE_REG);
+
 	if (cmd->scan_begin_src == TRIG_TIMER)
 		apci3120_timer_enable(dev, 1, true);
 	apci3120_timer_enable(dev, 0, true);