[PATCH v1 6/8] zorro: Simplify storing pointers in device id struct

[Uwe Kleine-König (The Capable Hub)]

Technically it is fine (on all current Linux architectures) to store a
pointer in an unsigned long variable. However this needs explicit
casting which is an easy source for type mismatches.

By replacing the plain unsigned long .driver_data in struct
zorro_device_id by an anonymous union, most of the casting can be
dropped. There is still some implicit casting involved (between a void *
and a driver specific pointer type), but that's better than the approach
to store a pointer in an unsigned long variable as this doesn't lose the
information that the data being pointed to is const.

All users of struct zorro_device_id are initialized in a way that is
compatible with the new definition, so no adaptions are needed there.

Signed-off-by: Uwe Kleine-König (The Capable Hub) <u.kleine-koenig@xxxxxxxxxxxx>
---
 include/linux/mod_devicetable.h | 6 +++++-
 1 file changed, 5 insertions(+), 1 deletion(-)

diff --git a/include/linux/mod_devicetable.h b/include/linux/mod_devicetable.h
index 3b0c9a251a2e..2673a1bd82c4 100644
--- a/include/linux/mod_devicetable.h
+++ b/include/linux/mod_devicetable.h
@@ -640,7 +640,11 @@ struct mdio_device_id {
 
 struct zorro_device_id {
 	__u32 id;			/* Device ID or ZORRO_WILDCARD */
-	kernel_ulong_t driver_data;	/* Data private to the driver */
+	union {
+		/* Data private to the driver */
+		kernel_ulong_t driver_data;
+		const void *driver_data_ptr;
+	};
 };
 
 #define ZORRO_WILDCARD			(0xffffffff)	/* not official */
-- 
2.47.3