staging: comedi: pcl818: consolidate the common interrupt code

The DMA, FIFO, and EOC interrupt handler functions, that are called by
the _real_ interrupt function, always return IRQ_HANDLED. Change the
return type for these functions to void and move the final return to
the real interrupt function.

Change the parameters to the handler functions to the comedi_device and
comedi_subdevice pointers.

At some point in the handler functions the interrupt request is cleared.
Move this to the real interrupt function.

Also at some point in the handlers, comedi_event() is called to pass any
events to the comedi subsystem. Move this to the real interrupt function
also.

For aesthetics, and to clarify the code, rename the interrupt function and
the handler functions.
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

@@ -562,7 +562,6 @@ static bool pcl818_ai_dropout(struct comedi_device *dev,
 			chan, expected_chan);
 		s->cancel(dev, s);
 		s->async->events |= COMEDI_CB_EOA | COMEDI_CB_ERROR;
-		comedi_event(dev, s);
 		return true;
 	}
 	return false;
@@ -591,17 +590,15 @@ static bool pcl818_ai_next_chan(struct comedi_device *dev,
 		/* all data sampled */
 		s->cancel(dev, s);
 		s->async->events |= COMEDI_CB_EOA;
-		comedi_event(dev, s);
 		return false;
 	}
 
 	return true;
 }
 
-static irqreturn_t interrupt_pcl818_ai_mode13_int(int irq, void *d)
+static void pcl818_handle_eoc(struct comedi_device *dev,
+			      struct comedi_subdevice *s)
 {
-	struct comedi_device *dev = d;
-	struct comedi_subdevice *s = dev->read_subdev;
 	unsigned int chan;
 	unsigned int val;
 
@@ -610,30 +607,24 @@ static irqreturn_t interrupt_pcl818_ai_mode13_int(int irq, void *d)
 		comedi_error(dev, "A/D mode1/3 IRQ without DRDY!");
 		s->cancel(dev, s);
 		s->async->events |= COMEDI_CB_EOA | COMEDI_CB_ERROR;
-		comedi_event(dev, s);
-		return IRQ_HANDLED;
+		return;
 	}
 
 	val = pcl818_ai_get_sample(dev, s, &chan);
 	outb(0, dev->iobase + PCL818_CLRINT);	/* clear INT request */
 
 	if (pcl818_ai_dropout(dev, s, chan))
-		return IRQ_HANDLED;
+		return;
 
 	comedi_buf_put(s->async, val);
 
-	if (!pcl818_ai_next_chan(dev, s))
-		return IRQ_HANDLED;
-
-	comedi_event(dev, s);
-	return IRQ_HANDLED;
+	pcl818_ai_next_chan(dev, s);
 }
 
-static irqreturn_t interrupt_pcl818_ai_mode13_dma(int irq, void *d)
+static void pcl818_handle_dma(struct comedi_device *dev,
+			      struct comedi_subdevice *s)
 {
-	struct comedi_device *dev = d;
 	struct pcl818_private *devpriv = dev->private;
-	struct comedi_subdevice *s = dev->read_subdev;
 	unsigned short *ptr;
 	unsigned int chan;
 	unsigned int val;
@@ -641,7 +632,6 @@ static irqreturn_t interrupt_pcl818_ai_mode13_dma(int irq, void *d)
 
 	pcl818_ai_setup_next_dma(dev, s);
 
-	outb(0, dev->iobase + PCL818_CLRINT);	/* clear INT request */
 	ptr = (unsigned short *)devpriv->dmabuf[1 - devpriv->next_dma_buf];
 
 	len = devpriv->hwdmasize >> 1;
@@ -653,46 +643,37 @@ static irqreturn_t interrupt_pcl818_ai_mode13_dma(int irq, void *d)
 		val = (val >> 4) & s->maxdata;
 
 		if (pcl818_ai_dropout(dev, s, chan))
-			return IRQ_HANDLED;
+			break;
 
 		comedi_buf_put(s->async, val);
 
 		if (!pcl818_ai_next_chan(dev, s))
-			return IRQ_HANDLED;
+			break;
 	}
-
-	if (len > 0)
-		comedi_event(dev, s);
-	return IRQ_HANDLED;
 }
 
-static irqreturn_t interrupt_pcl818_ai_mode13_fifo(int irq, void *d)
+static void pcl818_handle_fifo(struct comedi_device *dev,
+			       struct comedi_subdevice *s)
 {
-	struct comedi_device *dev = d;
-	struct comedi_subdevice *s = dev->read_subdev;
 	unsigned int status;
 	unsigned int chan;
 	unsigned int val;
 	int i, len;
 
-	outb(0, dev->iobase + PCL818_FI_INTCLR);	/*  clear fifo int request */
-
 	status = inb(dev->iobase + PCL818_FI_STATUS);
 
 	if (status & 4) {
 		comedi_error(dev, "A/D mode1/3 FIFO overflow!");
 		s->cancel(dev, s);
 		s->async->events |= COMEDI_CB_EOA | COMEDI_CB_ERROR;
-		comedi_event(dev, s);
-		return IRQ_HANDLED;
+		return;
 	}
 
 	if (status & 1) {
 		comedi_error(dev, "A/D mode1/3 FIFO interrupt without data!");
 		s->cancel(dev, s);
 		s->async->events |= COMEDI_CB_EOA | COMEDI_CB_ERROR;
-		comedi_event(dev, s);
-		return IRQ_HANDLED;
+		return;
 	}
 
 	if (status & 2)
@@ -704,20 +685,16 @@ static irqreturn_t interrupt_pcl818_ai_mode13_fifo(int irq, void *d)
 		val = pcl818_ai_get_fifo_sample(dev, s, &chan);
 
 		if (pcl818_ai_dropout(dev, s, chan))
-			return IRQ_HANDLED;
+			break;
 
 		comedi_buf_put(s->async, val);
 
 		if (!pcl818_ai_next_chan(dev, s))
-			return IRQ_HANDLED;
+			break;
 	}
-
-	if (len > 0)
-		comedi_event(dev, s);
-	return IRQ_HANDLED;
 }
 
-static irqreturn_t interrupt_pcl818(int irq, void *d)
+static irqreturn_t pcl818_interrupt(int irq, void *d)
 {
 	struct comedi_device *dev = d;
 	struct pcl818_private *devpriv = dev->private;
@@ -737,16 +714,21 @@ static irqreturn_t interrupt_pcl818(int irq, void *d)
 		 */
 		devpriv->ai_act_scan = 0;
 		s->cancel(dev, s);
-		outb(0, dev->iobase + PCL818_CLRINT);	/* clear INT request */
+		outb(0, dev->iobase + PCL818_CLRINT);
 		return IRQ_HANDLED;
 	}
 
 	if (devpriv->dma)
-		return interrupt_pcl818_ai_mode13_dma(irq, d);
+		pcl818_handle_dma(dev, s);
 	else if (devpriv->usefifo)
-		return interrupt_pcl818_ai_mode13_fifo(irq, d);
+		pcl818_handle_fifo(dev, s);
 	else
-		return interrupt_pcl818_ai_mode13_int(irq, d);
+		pcl818_handle_eoc(dev, s);
+
+	outb(0, dev->iobase + PCL818_CLRINT);
+
+	comedi_event(dev, s);
+	return IRQ_HANDLED;
 }
 
 static void pcl818_ai_mode13dma_int(int mode, struct comedi_device *dev,
@@ -1152,7 +1134,7 @@ static int pcl818_attach(struct comedi_device *dev, struct comedi_devconfig *it)
 
 	/* we can use IRQ 2-7 for async command support */
 	if (it->options[1] >= 2 && it->options[1] <= 7) {
-		ret = request_irq(it->options[1], interrupt_pcl818, 0,
+		ret = request_irq(it->options[1], pcl818_interrupt, 0,
 				  dev->board_name, dev);
 		if (ret == 0)
 			dev->irq = it->options[1];