staging: comedi: 8255: handle memory mapped io

The drivers that use this module with memory mapped io all have the
ioremap'ed base address stored in the comedi_device 'mmio' member.

Introduce a default (*io) function that does 8-bit memory mapped io.

Modify subdev_8255_init() so that it takes a flag parameter indicating
if the io is port or memory mapped. Make the function static and rename
it to __subdev_8255_init().

Introduce two exported wrappers for __subdev_8255_init():

  subdev_8255_init() - for drivers that do 8-bit port io
  subdev_8255_mm_init() - for drivers that do 8-bit memory mapped io

Use subdev_8255_mm_init() in the drivers that do 8-bit memory mapped io
and remove the private (*io) 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/8255.c

@@ -107,6 +107,16 @@ static int subdev_8255_io(struct comedi_device *dev,
 	return inb(dev->iobase + regbase + port);
 }
 
+static int subdev_8255_mmio(struct comedi_device *dev,
+			    int dir, int port, int data, unsigned long regbase)
+{
+	if (dir) {
+		writeb(data, dev->mmio + regbase + port);
+		return 0;
+	}
+	return readb(dev->mmio + regbase + port);
+}
+
 static int subdev_8255_insn(struct comedi_device *dev,
 			    struct comedi_subdevice *s,
 			    struct comedi_insn *insn,
@@ -186,10 +196,12 @@ static int subdev_8255_insn_config(struct comedi_device *dev,
 	return insn->n;
 }
 
-int subdev_8255_init(struct comedi_device *dev, struct comedi_subdevice *s,
-		     int (*io)(struct comedi_device *,
-			       int, int, int, unsigned long),
-		     unsigned long regbase)
+static int __subdev_8255_init(struct comedi_device *dev,
+			      struct comedi_subdevice *s,
+			      int (*io)(struct comedi_device *,
+					int, int, int, unsigned long),
+			      unsigned long regbase,
+			      bool is_mmio)
 {
 	struct subdev_8255_private *spriv;
 
@@ -197,8 +209,13 @@ int subdev_8255_init(struct comedi_device *dev, struct comedi_subdevice *s,
 	if (!spriv)
 		return -ENOMEM;
 
+	if (io)
+		spriv->io = io;
+	else if (is_mmio)
+		spriv->io = subdev_8255_mmio;
+	else
+		spriv->io = subdev_8255_io;
 	spriv->regbase	= regbase;
-	spriv->io	= io ? io : subdev_8255_io;
 
 	s->type		= COMEDI_SUBD_DIO;
 	s->subdev_flags	= SDF_READABLE | SDF_WRITABLE;
@@ -212,8 +229,24 @@ int subdev_8255_init(struct comedi_device *dev, struct comedi_subdevice *s,
 
 	return 0;
 }
+
+int subdev_8255_init(struct comedi_device *dev, struct comedi_subdevice *s,
+		     int (*io)(struct comedi_device *,
+			       int, int, int, unsigned long),
+		     unsigned long regbase)
+{
+	return __subdev_8255_init(dev, s, io, regbase, false);
+}
 EXPORT_SYMBOL_GPL(subdev_8255_init);
 
+int subdev_8255_mm_init(struct comedi_device *dev, struct comedi_subdevice *s,
+			int (*io)(struct comedi_device *,
+				  int, int, int, unsigned long),
+			unsigned long regbase)
+{
+	return __subdev_8255_init(dev, s, io, regbase, true);
+}
+EXPORT_SYMBOL_GPL(subdev_8255_mm_init);
 /*
 
    Start of the 8255 standalone device

drivers/staging/comedi/drivers/8255.h

@@ -21,9 +21,14 @@
 
 #include "../comedidev.h"
 
-int subdev_8255_init(struct comedi_device *dev, struct comedi_subdevice *s,
+int subdev_8255_init(struct comedi_device *, struct comedi_subdevice *,
 		     int (*io)(struct comedi_device *,
 			       int, int, int, unsigned long),
 		     unsigned long regbase);
 
+int subdev_8255_mm_init(struct comedi_device *, struct comedi_subdevice *,
+			int (*io)(struct comedi_device *,
+				  int, int, int, unsigned long),
+			unsigned long regbase);
+
 #endif

drivers/staging/comedi/drivers/8255_pci.c

@@ -190,23 +190,12 @@ static int pci_8255_mite_init(struct pci_dev *pcidev)
 	return 0;
 }
 
-static int pci_8255_mmio(struct comedi_device *dev,
-			 int dir, int port, int data, unsigned long iobase)
-{
-	if (dir) {
-		writeb(data, dev->mmio + iobase + port);
-		return 0;
-	}
-	return readb(dev->mmio + iobase  + port);
-}
-
 static int pci_8255_auto_attach(struct comedi_device *dev,
 				unsigned long context)
 {
 	struct pci_dev *pcidev = comedi_to_pci_dev(dev);
 	const struct pci_8255_boardinfo *board = NULL;
 	struct comedi_subdevice *s;
-	bool is_mmio;
 	int ret;
 	int i;
 
@@ -227,9 +216,7 @@ static int pci_8255_auto_attach(struct comedi_device *dev,
 			return ret;
 	}
 
-	is_mmio = (pci_resource_flags(pcidev, board->dio_badr) &
-		   IORESOURCE_MEM) != 0;
-	if (is_mmio) {
+	if ((pci_resource_flags(pcidev, board->dio_badr) & IORESOURCE_MEM)) {
 		dev->mmio = pci_ioremap_bar(pcidev, board->dio_badr);
 		if (!dev->mmio)
 			return -ENOMEM;
@@ -248,8 +235,8 @@ static int pci_8255_auto_attach(struct comedi_device *dev,
 
 	for (i = 0; i < board->n_8255; i++) {
 		s = &dev->subdevices[i];
-		if (is_mmio)
-			ret = subdev_8255_init(dev, s, pci_8255_mmio, i * 4);
+		if (dev->mmio)
+			ret = subdev_8255_mm_init(dev, s, NULL, i * 4);
 		else
 			ret = subdev_8255_init(dev, s, NULL, i * 4);
 		if (ret)

drivers/staging/comedi/drivers/cb_pcidas64.c

@@ -3369,16 +3369,6 @@ static int ao_cancel(struct comedi_device *dev, struct comedi_subdevice *s)
 	return 0;
 }
 
-static int dio_callback(struct comedi_device *dev,
-			int dir, int port, int data, unsigned long iobase)
-{
-	if (dir) {
-		writeb(data, dev->mmio + iobase + port);
-		return 0;
-	}
-	return readb(dev->mmio + iobase + port);
-}
-
 static int dio_callback_4020(struct comedi_device *dev,
 			     int dir, int port, int data, unsigned long iobase)
 {
@@ -3842,8 +3832,8 @@ static int setup_subdevices(struct comedi_device *dev)
 			ret = subdev_8255_init(dev, s, dio_callback_4020,
 					       I8255_4020_REG);
 		} else {
-			ret = subdev_8255_init(dev, s, dio_callback,
-					       DIO_8255_OFFSET);
+			ret = subdev_8255_mm_init(dev, s, NULL,
+						  DIO_8255_OFFSET);
 		}
 		if (ret)
 			return ret;

drivers/staging/comedi/drivers/ni_labpc.c

@@ -1035,17 +1035,6 @@ static int labpc_ao_insn_read(struct comedi_device *dev,
 	return 1;
 }
 
-static int labpc_8255_mmio(struct comedi_device *dev,
-			   int dir, int port, int data, unsigned long iobase)
-{
-	if (dir) {
-		writeb(data, dev->mmio + iobase + port);
-		return 0;
-	}
-
-	return readb(dev->mmio + iobase + port);
-}
-
 /* lowlevel write to eeprom/dac */
 static void labpc_serial_out(struct comedi_device *dev, unsigned int value,
 			     unsigned int value_width)
@@ -1402,8 +1391,7 @@ int labpc_common_attach(struct comedi_device *dev,
 	/* 8255 dio */
 	s = &dev->subdevices[2];
 	if (dev->mmio) {
-		ret = subdev_8255_init(dev, s, labpc_8255_mmio,
-				       DIO_BASE_REG);
+		ret = subdev_8255_mm_init(dev, s, NULL, DIO_BASE_REG);
 	} else {
 		ret = subdev_8255_init(dev, s, NULL, DIO_BASE_REG);
 	}