[PATCH 09/11] HID: mod_devicetable: 'hid_device_id::driver_data' add union

[Pawel Zalewski (The Capable Hub)]

The 'driver_data' field can either be interpreted as an unsigned
numerical number or as a pointer - this depends on the driver within
HID subsystem. Unionise this unsigned value with a 'const void*'
pointer. This change allows to remove explicit casts to pointers
in the pointer-users case and as far as integer-users of the field
are concerned nothing has really changed.

The change doesn't affect the size and layout of struct hid_device_id
which is part of the userspace ABI.

This change aims to improve type-safety, readability - as the
intent is more clear - and portability of the code in the long term.

Signed-off-by: Pawel Zalewski (The Capable Hub) <pzalewski@xxxxxxxxxxxxxxxxxxxx>
---
 include/linux/mod_devicetable.h | 5 ++++-
 1 file changed, 4 insertions(+), 1 deletion(-)

diff --git a/include/linux/mod_devicetable.h b/include/linux/mod_devicetable.h
index 23ff24080dfd..90b2dae75109 100644
--- a/include/linux/mod_devicetable.h
+++ b/include/linux/mod_devicetable.h
@@ -175,7 +175,10 @@ struct hid_device_id {
 	__u16 group;
 	__u32 vendor;
 	__u32 product;
-	kernel_ulong_t driver_data;
+	union {
+		kernel_ulong_t driver_data;
+		const void *driver_data_ptr;
+	};
 };
 
 /* s390 CCW devices */

-- 
2.43.0