diff --git a/arch/arm/mach-omap2/io.c b/arch/arm/mach-omap2/io.c
index 402e8f0d0f211085838d14f4cb3bf84c93ea25ed..ae89d55132d1b992342d70208b72c6d9121d4db7 100644
--- a/arch/arm/mach-omap2/io.c
+++ b/arch/arm/mach-omap2/io.c
@@ -237,7 +237,7 @@ static void __init _omap2_map_common_io(void)
 }
 
 #ifdef CONFIG_ARCH_OMAP2420
-void __init omap242x_map_common_io()
+void __init omap242x_map_common_io(void)
 {
 	iotable_init(omap24xx_io_desc, ARRAY_SIZE(omap24xx_io_desc));
 	iotable_init(omap242x_io_desc, ARRAY_SIZE(omap242x_io_desc));
@@ -246,7 +246,7 @@ void __init omap242x_map_common_io()
 #endif
 
 #ifdef CONFIG_ARCH_OMAP2430
-void __init omap243x_map_common_io()
+void __init omap243x_map_common_io(void)
 {
 	iotable_init(omap24xx_io_desc, ARRAY_SIZE(omap24xx_io_desc));
 	iotable_init(omap243x_io_desc, ARRAY_SIZE(omap243x_io_desc));
@@ -255,7 +255,7 @@ void __init omap243x_map_common_io()
 #endif
 
 #ifdef CONFIG_ARCH_OMAP3
-void __init omap34xx_map_common_io()
+void __init omap34xx_map_common_io(void)
 {
 	iotable_init(omap34xx_io_desc, ARRAY_SIZE(omap34xx_io_desc));
 	_omap2_map_common_io();
@@ -263,7 +263,7 @@ void __init omap34xx_map_common_io()
 #endif
 
 #ifdef CONFIG_ARCH_OMAP4
-void __init omap44xx_map_common_io()
+void __init omap44xx_map_common_io(void)
 {
 	iotable_init(omap44xx_io_desc, ARRAY_SIZE(omap44xx_io_desc));
 	_omap2_map_common_io();