clocksource: make CLOCKSOURCE_OF_DECLARE type safe

This ensures that a function pointer passed into CLOCKSOURCE_OF_DECLARE
takes the same arguments that we use for calling that function later.

Also fix the extraneous semicolon at end of the CLOCKSOURCE_OF_DECLARE
definition.

Signed-off-by: Arnd Bergmann <arnd@arndb.de>
Acked-by: Rob Herring <rob.herring@calxeda.com>

3 files changed, 12 insertions, 4 deletions

diff --git a/drivers/clocksource/clksrc-of.c b/drivers/clocksource/clksrc-of.c
index 3ef11fba781c..37f5325bec95 100644
--- a/drivers/clocksource/clksrc-of.c
+++ b/drivers/clocksource/clksrc-of.c
@@ -16,6 +16,7 @@
 
 #include <linux/init.h>
 #include <linux/of.h>
+#include <linux/clocksource.h>
 
 extern struct of_device_id __clksrc_of_table[];
 
@@ -26,7 +27,7 @@ void __init clocksource_of_init(void)
 {
         struct device_node *np;
         const struct of_device_id *match;
-        void (*init_func)(struct device_node *);
+        clocksource_of_init_fn init_func;
 
         for_each_matching_node_and_match(np, __clksrc_of_table, &match) {
                 init_func = match->data;
diff --git a/drivers/clocksource/vt8500_timer.c b/drivers/clocksource/vt8500_timer.c
index 242255285597..64f553f04fa4 100644
--- a/drivers/clocksource/vt8500_timer.c
+++ b/drivers/clocksource/vt8500_timer.c
@@ -165,4 +165,4 @@ static void __init vt8500_timer_init(struct device_node *np)
                                         4, 0xf0000000);
 }
 
-CLOCKSOURCE_OF_DECLARE(vt8500, "via,vt8500-timer", vt8500_timer_init)
+CLOCKSOURCE_OF_DECLARE(vt8500, "via,vt8500-timer", vt8500_timer_init);
diff --git a/include/linux/clocksource.h b/include/linux/clocksource.h
index 08ed5e19d8c6..ac33184b14fd 100644
--- a/include/linux/clocksource.h
+++ b/include/linux/clocksource.h
@@ -332,16 +332,23 @@ extern int clocksource_mmio_init(void __iomem *, const char *,
 
 extern int clocksource_i8253_init(void);
 
+struct device_node;
+typedef void(*clocksource_of_init_fn)(struct device_node *);
 #ifdef CONFIG_CLKSRC_OF
 extern void clocksource_of_init(void);
 
 #define CLOCKSOURCE_OF_DECLARE(name, compat, fn)                        \
         static const struct of_device_id __clksrc_of_table_##name       \
                 __used __section(__clksrc_of_table)                     \
-                 = { .compatible = compat, .data = fn };
+                 = { .compatible = compat,                              \
+                     .data = (fn == (clocksource_of_init_fn)NULL) ? fn : fn }
 #else
 static inline void clocksource_of_init(void) {}
-#define CLOCKSOURCE_OF_DECLARE(name, compat, fn)
+#define CLOCKSOURCE_OF_DECLARE(name, compat, fn)                        \
+        static const struct of_device_id __clksrc_of_table_##name       \
+                __unused __section(__clksrc_of_table)                   \
+                 = { .compatible = compat,                              \
+                     .data = (fn == (clocksource_of_init_fn)NULL) ? fn : fn }
 #endif
 
 #endif /* _LINUX_CLOCKSOURCE_H */