diff --git a/drivers/rtc/rtc-cmos.c b/drivers/rtc/rtc-cmos.c
index 5856167..7e6ce62 100644
--- a/drivers/rtc/rtc-cmos.c
+++ b/drivers/rtc/rtc-cmos.c
@@ -687,7 +687,8 @@
 #if	defined(CONFIG_ATARI)
 	address_space = 64;
 #elif defined(__i386__) || defined(__x86_64__) || defined(__arm__) \
-			|| defined(__sparc__) || defined(__mips__)
+			|| defined(__sparc__) || defined(__mips__) \
+			|| defined(__powerpc__)
 	address_space = 128;
 #else
 #warning Assuming 128 bytes of RTC+NVRAM address space, not 64 bytes.