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authorFeng Tang <feng.tang@intel.com>2010-11-17 07:11:24 -0500
committerThomas Gleixner <tglx@linutronix.de>2010-11-17 07:53:46 -0500
commitd3e1884bc585a43674d2cb0d3f0aeeb0ae43bc04 (patch)
tree538132e2504bddc147d644ad09eb6829e4f2915f
parentad02519a0d27da4a0a50cbc696e810c94e27c28e (diff)
x86, mrst: Add explanation for using 1960 as the year offset for vrtc
Explain the reason for the apparently odd choice of year offset so we don't get more questions about it. Signed-off-by: Feng Tang <feng.tang@intel.com> Signed-off-by: Alan Cox <alan@linux.intel.com> LKML-Reference: <20101117121050.9998.89348.stgit@localhost.localdomain> Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
-rw-r--r--drivers/rtc/rtc-mrst.c6
1 files changed, 5 insertions, 1 deletions
diff --git a/drivers/rtc/rtc-mrst.c b/drivers/rtc/rtc-mrst.c
index 67b6be2b874d..bcd0cf63eb16 100644
--- a/drivers/rtc/rtc-mrst.c
+++ b/drivers/rtc/rtc-mrst.c
@@ -66,7 +66,11 @@ static inline int is_intr(u8 rtc_intr)
66 * rtc_time's year contains the increment over 1900, but vRTC's YEAR 66 * rtc_time's year contains the increment over 1900, but vRTC's YEAR
67 * register can't be programmed to value larger than 0x64, so vRTC 67 * register can't be programmed to value larger than 0x64, so vRTC
68 * driver chose to use 1960 (1970 is UNIX time start point) as the base, 68 * driver chose to use 1960 (1970 is UNIX time start point) as the base,
69 * and does the translation at read/write time 69 * and does the translation at read/write time.
70 *
71 * Why not just use 1970 as the offset? it's because using 1960 will
72 * make it consistent in leap year setting for both vrtc and low-level
73 * physical rtc devices.
70 */ 74 */
71static int mrst_read_time(struct device *dev, struct rtc_time *time) 75static int mrst_read_time(struct device *dev, struct rtc_time *time)
72{ 76{