The comedi_8254 module supports both port I/O and memory-mapped I/O.
In a future patch, the port I/O functions (`inb()`, `outb()`, and
friends) will only be declared if the `HAS_IOPORT` configuration option
is enabled.
Conditionally compile the parts of the module that use port I/O so they
are compiled 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 `CONFIG_HAS_IOPORT` is undefined, replace the GPL-exported
`comedi_8254_io_alloc()` function with a dummy static inline version
that just returns `ERR_PTR(-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_8254.c | 8 ++++++++
include/linux/comedi/comedi_8254.h | 13 +++++++++++++
2 files changed, 21 insertions(+)
@@ -122,6 +122,8 @@
#include <linux/comedi/comedidev.h>
#include <linux/comedi/comedi_8254.h>
+#ifdef CONFIG_HAS_IOPORT
+
static unsigned int i8254_io8_cb(struct comedi_8254 *i8254, int dir,
unsigned int reg, unsigned int val)
{
@@ -164,6 +166,8 @@ static unsigned int i8254_io32_cb(struct comedi_8254 *i8254, int dir,
}
}
+#endif /* CONFIG_HAS_IOPORT */
+
static unsigned int i8254_mmio8_cb(struct comedi_8254 *i8254, int dir,
unsigned int reg, unsigned int val)
{
@@ -648,6 +652,8 @@ static struct comedi_8254 *__i8254_init(comedi_8254_iocb_fn *iocb,
return i8254;
}
+#ifdef CONFIG_HAS_IOPORT
+
/**
* comedi_8254_io_alloc - allocate and initialize the 8254 device for pio access
* @iobase: port I/O base address
@@ -682,6 +688,8 @@ struct comedi_8254 *comedi_8254_io_alloc(unsigned long iobase,
}
EXPORT_SYMBOL_GPL(comedi_8254_io_alloc);
+#endif /* CONFIG_HAS_IOPORT */
+
/**
* comedi_8254_mm_alloc - allocate and initialize the 8254 device for mmio access
* @mmio: memory mapped I/O base address
@@ -12,6 +12,8 @@
#define _COMEDI_8254_H
#include <linux/types.h>
+#include <linux/errno.h>
+#include <linux/err.h>
struct comedi_device;
struct comedi_insn;
@@ -136,10 +138,21 @@ void comedi_8254_set_busy(struct comedi_8254 *i8254,
void comedi_8254_subdevice_init(struct comedi_subdevice *s,
struct comedi_8254 *i8254);
+#ifdef CONFIG_HAS_IOPORT
struct comedi_8254 *comedi_8254_io_alloc(unsigned long iobase,
unsigned int osc_base,
unsigned int iosize,
unsigned int regshift);
+#else
+static inline struct comedi_8254 *comedi_8254_io_alloc(unsigned long iobase,
+ unsigned int osc_base,
+ unsigned int iosize,
+ unsigned int regshift)
+{
+ return ERR_PTR(-ENXIO);
+}
+#endif
+
struct comedi_8254 *comedi_8254_mm_alloc(void __iomem *mmio,
unsigned int osc_base,
unsigned int iosize,