staging: comedi: pcl816: consolidate the interrupt code

This driver only supports interrupt driven DMA transfers for async
command support. Absorb the interrupt_pcl816_ai_mode13_dma() helper
into the interrupt handler to clarify the code.

At some point during the interrupt, comedi_event() is called to pass
any events to the comedi subsystem. Move this to the interrupt handler.
Add a comedi_event() call to pcl816_ai_poll() due to the removal of
the call from transfer_from_dma_buf().

For aesthetics, rename the interrupt 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/pcl816.c

@@ -286,7 +286,6 @@ static bool pcl816_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;
 	}
 
@@ -306,51 +305,42 @@ static void transfer_from_dma_buf(struct comedi_device *dev,
 		if (!pcl816_ai_next_chan(dev, s))
 			return;
 	}
-
-	comedi_event(dev, s);
 }
 
-static irqreturn_t interrupt_pcl816_ai_mode13_dma(int irq, void *d)
+static irqreturn_t pcl816_interrupt(int irq, void *d)
 {
 	struct comedi_device *dev = d;
-	struct pcl816_private *devpriv = dev->private;
 	struct comedi_subdevice *s = dev->read_subdev;
-	int len, bufptr, this_dma_buf;
+	struct pcl816_private *devpriv = dev->private;
 	unsigned short *ptr;
+	unsigned int bufptr;
+	unsigned int len;
 
-	this_dma_buf = devpriv->next_dma_buf;
+	if (!dev->attached || !devpriv->ai_cmd_running) {
+		outb(0, dev->iobase + PCL816_CLRINT);
+		return IRQ_HANDLED;
+	}
 
-	pcl816_ai_setup_next_dma(dev, s);
+	if (devpriv->ai_cmd_canceled) {
+		devpriv->ai_cmd_canceled = 0;
+		outb(0, dev->iobase + PCL816_CLRINT);
+		return IRQ_HANDLED;
+	}
 
-	outb(0, dev->iobase + PCL816_CLRINT);	/* clear INT request */
+	ptr = (unsigned short *)devpriv->dmabuf[devpriv->next_dma_buf];
 
-	ptr = (unsigned short *)devpriv->dmabuf[this_dma_buf];
+	pcl816_ai_setup_next_dma(dev, s);
 
 	len = (devpriv->hwdmasize >> 1) - devpriv->ai_poll_ptr;
 	bufptr = devpriv->ai_poll_ptr;
 	devpriv->ai_poll_ptr = 0;
 
 	transfer_from_dma_buf(dev, s, ptr, bufptr, len);
-	return IRQ_HANDLED;
-}
-
-static irqreturn_t interrupt_pcl816(int irq, void *d)
-{
-	struct comedi_device *dev = d;
-	struct pcl816_private *devpriv = dev->private;
 
-	if (!dev->attached || !devpriv->ai_cmd_running) {
 	outb(0, dev->iobase + PCL816_CLRINT);
-		return IRQ_HANDLED;
-	}
 
-	if (devpriv->ai_cmd_canceled) {
-		devpriv->ai_cmd_canceled = 0;
-		outb(0, dev->iobase + PCL816_CLRINT);
+	comedi_event(dev, s);
 	return IRQ_HANDLED;
-	}
-
-	return interrupt_pcl816_ai_mode13_dma(irq, d);
 }
 
 static int pcl816_ai_cmdtest(struct comedi_device *dev,
@@ -521,6 +511,8 @@ static int pcl816_ai_poll(struct comedi_device *dev, struct comedi_subdevice *s)
 	devpriv->ai_poll_ptr = top1;	/*  new buffer position */
 	spin_unlock_irqrestore(&dev->spinlock, flags);
 
+	comedi_event(dev, s);
+
 	return s->async->buf_write_count - s->async->buf_read_count;
 }
 
@@ -676,7 +668,7 @@ static int pcl816_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_pcl816, 0,
+		ret = request_irq(it->options[1], pcl816_interrupt, 0,
 				  dev->board_name, dev);
 		if (ret == 0)
 			dev->irq = it->options[1];