comedi: comedi_8255: Conditionally remove I/O port support

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_IOPORT` 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>
Link: https://lore.kernel.org/r/20230913170712.111719-8-abbotti@mev.co.uk
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

diff --git a/drivers/comedi/drivers/comedi_8255.c b/drivers/comedi/drivers/comedi_8255.c
index 28fd9d8c95cca9d3eff1aff6d8f429d689d78ade..e4974b508328d1ae50e839602c572581f15ada56 100644 (file)
--- a/drivers/comedi/drivers/comedi_8255.c
+++ b/drivers/comedi/drivers/comedi_8255.c
@@ -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

diff --git a/include/linux/comedi/comedi_8255.h b/include/linux/comedi/comedi_8255.h
index b396fcfbf8b00ae80d1a39666e165ed705df7773..d24a69da389b8d59627a1b1230f6dd7be4a9923f 100644 (file)
--- a/include/linux/comedi/comedi_8255.h
+++ b/include/linux/comedi/comedi_8255.h
@@ -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);