staging: comedi: pcl818: factor out the common "dropout" detect code

The DMA, FIFO, and EOC interrupt handlers all have common code that
checks for channel dropout when running an async command.

Factor this common code into a helper function.

Only return the sample if the channel is valid. The EOC handler was
previously returning the value then checking for channel dropout.
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/pcl818.c

@@ -555,6 +555,28 @@ static int pcl818_do_insn_bits(struct comedi_device *dev,
 	return insn->n;
 }
 
+static bool pcl818_ai_dropout(struct comedi_device *dev,
+			      struct comedi_subdevice *s,
+			      unsigned int chan)
+{
+	struct pcl818_private *devpriv = dev->private;
+	unsigned int expected_chan;
+
+	expected_chan = devpriv->act_chanlist[devpriv->act_chanlist_pos];
+	if (chan != expected_chan) {
+		dev_dbg(dev->class_dev,
+			"A/D mode1/3 %s - channel dropout %d!=%d !\n",
+			(devpriv->dma) ? "DMA" :
+			(devpriv->usefifo) ? "FIFO" : "IRQ",
+			chan, expected_chan);
+		s->cancel(dev, s);
+		s->async->events |= COMEDI_CB_EOA | COMEDI_CB_ERROR;
+		comedi_event(dev, s);
+		return true;
+	}
+	return false;
+}
+
 static bool pcl818_ai_next_chan(struct comedi_device *dev,
 				struct comedi_subdevice *s)
 {
@@ -588,9 +610,9 @@ static bool pcl818_ai_next_chan(struct comedi_device *dev,
 static irqreturn_t interrupt_pcl818_ai_mode13_int(int irq, void *d)
 {
 	struct comedi_device *dev = d;
-	struct pcl818_private *devpriv = dev->private;
 	struct comedi_subdevice *s = dev->read_subdev;
 	unsigned int chan;
+	unsigned int val;
 
 	if (pcl818_ai_eoc(dev, s, NULL, 0)) {
 		outb(0, dev->iobase + PCL818_STATUS);	/* clear INT request */
@@ -601,19 +623,13 @@ static irqreturn_t interrupt_pcl818_ai_mode13_int(int irq, void *d)
 		return IRQ_HANDLED;
 	}
 
-	comedi_buf_put(s->async, pcl818_ai_get_sample(dev, s, &chan));
+	val = pcl818_ai_get_sample(dev, s, &chan);
 	outb(0, dev->iobase + PCL818_CLRINT);	/* clear INT request */
 
-	if (chan != devpriv->act_chanlist[devpriv->act_chanlist_pos]) {
-		dev_dbg(dev->class_dev,
-			"A/D mode1/3 IRQ - channel dropout %x!=%x !\n",
-			chan,
-			devpriv->act_chanlist[devpriv->act_chanlist_pos]);
-		s->cancel(dev, s);
-		s->async->events |= COMEDI_CB_EOA | COMEDI_CB_ERROR;
-		comedi_event(dev, s);
+	if (pcl818_ai_dropout(dev, s, chan))
 		return IRQ_HANDLED;
-	}
+
+	comedi_buf_put(s->async, val);
 
 	if (!pcl818_ai_next_chan(dev, s))
 		return IRQ_HANDLED;
@@ -627,8 +643,10 @@ static irqreturn_t interrupt_pcl818_ai_mode13_dma(int irq, void *d)
 	struct comedi_device *dev = d;
 	struct pcl818_private *devpriv = dev->private;
 	struct comedi_subdevice *s = dev->read_subdev;
-	int i, len, bufptr;
 	unsigned short *ptr;
+	unsigned int chan;
+	unsigned int val;
+	int i, len, bufptr;
 
 	pcl818_ai_setup_next_dma(dev, s);
 
@@ -639,19 +657,14 @@ static irqreturn_t interrupt_pcl818_ai_mode13_dma(int irq, void *d)
 	bufptr = 0;
 
 	for (i = 0; i < len; i++) {
-		if ((ptr[bufptr] & 0xf) != devpriv->act_chanlist[devpriv->act_chanlist_pos]) {	/*  dropout! */
-			dev_dbg(dev->class_dev,
-				"A/D mode1/3 DMA - channel dropout %d(card)!=%d(chanlist) at %d !\n",
-				(ptr[bufptr] & 0xf),
-				devpriv->act_chanlist[devpriv->act_chanlist_pos],
-				devpriv->act_chanlist_pos);
-			s->cancel(dev, s);
-			s->async->events |= COMEDI_CB_EOA | COMEDI_CB_ERROR;
-			comedi_event(dev, s);
+		val = ptr[bufptr++];
+		chan = val & 0xf;
+		val = (val >> 4) & s->maxdata;
+
+		if (pcl818_ai_dropout(dev, s, chan))
 			return IRQ_HANDLED;
-		}
 
-		comedi_buf_put(s->async, ptr[bufptr++] >> 4);	/*  get one sample */
+		comedi_buf_put(s->async, val);
 
 		if (!pcl818_ai_next_chan(dev, s))
 			return IRQ_HANDLED;
@@ -665,7 +678,6 @@ static irqreturn_t interrupt_pcl818_ai_mode13_dma(int irq, void *d)
 static irqreturn_t interrupt_pcl818_ai_mode13_fifo(int irq, void *d)
 {
 	struct comedi_device *dev = d;
-	struct pcl818_private *devpriv = dev->private;
 	struct comedi_subdevice *s = dev->read_subdev;
 	unsigned int status;
 	unsigned int chan;
@@ -699,16 +711,9 @@ static irqreturn_t interrupt_pcl818_ai_mode13_fifo(int irq, void *d)
 
 	for (i = 0; i < len; i++) {
 		val = pcl818_ai_get_fifo_sample(dev, s, &chan);
-		if (chan != devpriv->act_chanlist[devpriv->act_chanlist_pos]) {
-			dev_dbg(dev->class_dev,
-				"A/D mode1/3 FIFO - channel dropout %d!=%d !\n",
-				chan,
-				devpriv->act_chanlist[devpriv->act_chanlist_pos]);
-			s->cancel(dev, s);
-			s->async->events |= COMEDI_CB_EOA | COMEDI_CB_ERROR;
-			comedi_event(dev, s);
+
+		if (pcl818_ai_dropout(dev, s, chan))
 			return IRQ_HANDLED;
-		}
 
 		comedi_buf_put(s->async, val);