[PATCH] char/rtc: Handle memory-mapped chips properly

Handle memory-mapped chips properly, needed for example on DECstations.
This support was in Linux 2.4 but for some reason got lost in 2.6.  This
patch is taken directly from the linux-mips repository.

[akpm@osdl.org: cleanup]
Signed-off-by: Maciej W. Rozycki <macro@linux-mips.org>
Signed-off-by: Martin Michlmayr <tbm@cyrius.com>
Cc: Paul Gortmaker <penguin@muskoka.com>
Cc: Ralf Baechle <ralf@linux-mips.org>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>

1 files changed, 7 insertions, 0 deletions

diff --git a/include/linux/mc146818rtc.h b/include/linux/mc146818rtc.h
index bbc93ae217e1..432b2fa24929 100644
--- a/include/linux/mc146818rtc.h
+++ b/include/linux/mc146818rtc.h
@@ -89,4 +89,11 @@ extern spinlock_t rtc_lock;		/* serialize CMOS RAM access */
 # define RTC_VRT 0x80           /* valid RAM and time */
 /**********************************************************************/
 
+#ifndef ARCH_RTC_LOCATION       /* Override by <asm/mc146818rtc.h>? */
+
+#define RTC_IO_EXTENT   0x8
+#define RTC_IOMAPPED    1       /* Default to I/O mapping. */
+
+#endif /* ARCH_RTC_LOCATION */
+
 #endif /* _MC146818RTC_H */