comedi: amplc_dio200_common: Refactor register access functions

The `dio200_read8()`, `dio200_write8()`, `dio200_read32()` and
`dio200_write32()` functions apply a right-shift to the register offset
for some devices and then perform the actual register access.  Factor
the register access part out to new functions `dio200___read8()`,
`dio200___write8()`, `dio200___read32()`, and `dio200___write32()`.
This will reduce duplicated code in a subsequent patch that will
conditionally compile support for port I/O as part of the `HAS_IOPORT`
changes.

Cc: Arnd Bergmann <[email protected]>
Cc: Niklas Schnelle <[email protected]>
Signed-off-by: Ian Abbott <[email protected]>
Link: https://lore.kernel.org/r/[email protected]
Signed-off-by: Greg Kroah-Hartman <[email protected]>

drivers/comedi/drivers/amplc_dio200_common.c

@@ -86,6 +86,40 @@ struct dio200_subdev_intr {
 	unsigned int active:1;
 };
 
+static unsigned char dio200___read8(struct comedi_device *dev,
+				    unsigned int offset)
+{
+	if (dev->mmio)
+		return readb(dev->mmio + offset);
+	return inb(dev->iobase + offset);
+}
+
+static void dio200___write8(struct comedi_device *dev,
+			    unsigned int offset, unsigned char val)
+{
+	if (dev->mmio)
+		writeb(val, dev->mmio + offset);
+	else
+		outb(val, dev->iobase + offset);
+}
+
+static unsigned int dio200___read32(struct comedi_device *dev,
+				    unsigned int offset)
+{
+	if (dev->mmio)
+		return readl(dev->mmio + offset);
+	return inl(dev->iobase + offset);
+}
+
+static void dio200___write32(struct comedi_device *dev,
+			     unsigned int offset, unsigned int val)
+{
+	if (dev->mmio)
+		writel(val, dev->mmio + offset);
+	else
+		outl(val, dev->iobase + offset);
+}
+
 static unsigned char dio200_read8(struct comedi_device *dev,
 				  unsigned int offset)
 {
@@ -94,9 +128,7 @@ static unsigned char dio200_read8(struct comedi_device *dev,
 	if (board->is_pcie)
 		offset <<= 3;
 
-	if (dev->mmio)
-		return readb(dev->mmio + offset);
-	return inb(dev->iobase + offset);
+	return dio200___read8(dev, offset);
 }
 
 static void dio200_write8(struct comedi_device *dev,
@@ -107,10 +139,7 @@ static void dio200_write8(struct comedi_device *dev,
 	if (board->is_pcie)
 		offset <<= 3;
 
-	if (dev->mmio)
-		writeb(val, dev->mmio + offset);
-	else
-		outb(val, dev->iobase + offset);
+	dio200___write8(dev, offset, val);
 }
 
 static unsigned int dio200_read32(struct comedi_device *dev,
@@ -121,9 +150,7 @@ static unsigned int dio200_read32(struct comedi_device *dev,
 	if (board->is_pcie)
 		offset <<= 3;
 
-	if (dev->mmio)
-		return readl(dev->mmio + offset);
-	return inl(dev->iobase + offset);
+	return dio200___read32(dev, offset);
 }
 
 static void dio200_write32(struct comedi_device *dev,
@@ -134,10 +161,7 @@ static void dio200_write32(struct comedi_device *dev,
 	if (board->is_pcie)
 		offset <<= 3;
 
-	if (dev->mmio)
-		writel(val, dev->mmio + offset);
-	else
-		outl(val, dev->iobase + offset);
+	dio200___write32(dev, offset, val);
 }
 
 static unsigned int dio200_subdev_8254_offset(struct comedi_device *dev,