Linux kernel mirror (for testing)
git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git
tjh.dev
kernel
os
linux
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>
authored by Feng Tang and committed by Thomas Gleixner d3e1884b ad02519a
+5
-1
drivers/rtc/rtc-mrst.c
+5
-1
drivers/rtc/rtc-mrst.c
···
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
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* driver chose to use 1960 (1970 is UNIX time start point) as the base,
69
-
* and does the translation at read/write time
70
*/
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static int mrst_read_time(struct device *dev, struct rtc_time *time)
72
{
···
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
68
* driver chose to use 1960 (1970 is UNIX time start point) as the base,
69
+
* and does the translation at read/write time.
70
+
*
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+
* 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
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+
* physical rtc devices.
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*/
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static int mrst_read_time(struct device *dev, struct rtc_time *time)
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{