--- a/arch/powerpc/platforms/Kconfig
+++ b/arch/powerpc/platforms/Kconfig
@@ -147,6 +147,10 @@ config GENERIC_IOMAP
bool
default n
+config RB_IOMAP
+ bool
+ default y if RB_PPC
+
source "drivers/cpufreq/Kconfig"
menu "CPU Frequency drivers"