Building with W=1 complains:
CC [M] drivers/platform/x86/dell-rbtn.o
drivers/platform/x86/dell-rbtn.c:345:5: warning: no previous prototype for 'dell_rbtn_notifier_register' [-Wmissing-prototypes]
345 | int dell_rbtn_notifier_register(struct notifier_block *nb)
| ^~~~~~~~~~~~~~~~~~~~~~~~~~~
drivers/platform/x86/dell-rbtn.c:371:5: warning: no previous prototype for 'dell_rbtn_notifier_unregister' [-Wmissing-prototypes]
371 | int dell_rbtn_notifier_unregister(struct notifier_block *nb)
| ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~
The real problem is a missing include. Add it to keep dell-rbtn.c and .h in sync
Signed-off-by: Valdis Kletnieks <valdis.kletnieks@xxxxxx>
diff --git a/drivers/platform/x86/dell-rbtn.c b/drivers/platform/x86/dell-rbtn.c
index f3afe778001e..d50ca96d99f0 100644
--- a/drivers/platform/x86/dell-rbtn.c
+++ b/drivers/platform/x86/dell-rbtn.c
@@ -17,6 +17,7 @@
#include <linux/acpi.h>
#include <linux/rfkill.h>
#include <linux/input.h>
+#include "dell-rbtn.h"
enum rbtn_type {
RBTN_UNKNOWN,
