In a future patch, the port I/O functions (`inb()`, `outb()`, and
friends will only be declared in the `HAS_IOPORT` configuration option
is enabled.
The comedi_8255 module supports both port I/O and memory-mapped I/O.
Conditionally compile the parts of the module that use port I/O if and
only if the `CONFIG_HAS_PORTIO` macro is defined so that it can still be
built if the port I/O functions have not been declared. If the
`CONFIG_HAS_IOPORT` macro is undefined, replace the GPL-exported
`subdev_8255_io_init()` function with a dummy static inline version that
just returns `-ENXIO`.
Cc: Arnd Bergmann <arnd@kernel.org>
Cc: Niklas Schnelle <schnelle@linux.ibm.com>
Signed-off-by: Ian Abbott <abbotti@mev.co.uk>
---
drivers/comedi/drivers/comedi_8255.c | 8 ++++++++
include/linux/comedi/comedi_8255.h | 11 +++++++++++
2 files changed, 19 insertions(+)
@@ -38,6 +38,8 @@ struct subdev_8255_private {
unsigned long context);
};
+#ifdef CONFIG_HAS_IOPORT
+
static int subdev_8255_io(struct comedi_device *dev,
int dir, int port, int data, unsigned long regbase)
{
@@ -48,6 +50,8 @@ static int subdev_8255_io(struct comedi_device *dev,
return inb(dev->iobase + regbase + port);
}
+#endif /* CONFIG_HAS_IOPORT */
+
static int subdev_8255_mmio(struct comedi_device *dev,
int dir, int port, int data, unsigned long regbase)
{
@@ -169,6 +173,8 @@ static int __subdev_8255_init(struct comedi_device *dev,
return 0;
}
+#ifdef CONFIG_HAS_IOPORT
+
/**
* subdev_8255_io_init - initialize DIO subdevice for driving I/O mapped 8255
* @dev: comedi device owning subdevice
@@ -186,6 +192,8 @@ int subdev_8255_io_init(struct comedi_device *dev, struct comedi_subdevice *s,
}
EXPORT_SYMBOL_GPL(subdev_8255_io_init);
+#endif /* CONFIG_HAS_IOPORT */
+
/**
* subdev_8255_mm_init - initialize DIO subdevice for driving mmio-mapped 8255
* @dev: comedi device owning subdevice
@@ -10,6 +10,8 @@
#ifndef _COMEDI_8255_H
#define _COMEDI_8255_H
+#include <linux/errno.h>
+
#define I8255_SIZE 0x04
#define I8255_DATA_A_REG 0x00
@@ -27,8 +29,17 @@
struct comedi_device;
struct comedi_subdevice;
+#ifdef CONFIG_HAS_IOPORT
int subdev_8255_io_init(struct comedi_device *dev, struct comedi_subdevice *s,
unsigned long regbase);
+#else
+static inline int subdev_8255_io_init(struct comedi_device *dev,
+ struct comedi_subdevice *s,
+ unsigned long regbase)
+{
+ return -ENXIO;
+}
+#endif
int subdev_8255_mm_init(struct comedi_device *dev, struct comedi_subdevice *s,
unsigned long regbase);