The patch titled
rtc: m41t80: cenutury bit support
has been added to the -mm tree. Its filename is
rtc-m41t80-century-bit-support.patch
Before you just go and hit "reply", please:
a) Consider who else should be cc'ed
b) Prefer to cc a suitable mailing list as well
c) Ideally: find the original patch on the mailing list and do a
reply-to-all to that, adding suitable additional cc's
*** Remember to use Documentation/SubmitChecklist when testing your code ***
See http://www.zip.com.au/~akpm/linux/patches/stuff/added-to-mm.txt to find
out what to do about this
The current -mm tree may be found at http://userweb.kernel.org/~akpm/mmotm/
------------------------------------------------------
Subject: rtc: m41t80: cenutury bit support
From: "Maciej W. Rozycki" <macro@xxxxxxxxxxxxxx>
Make use of the Century Bit to support years in the range from 1970 to
2169. Enable toggling of the bit at the end of a century on a clock
update.
The clock is used with the Broadcom SWARM and the D-Link DNS-323 platform.
I have verified correct operation with the SWARM -- the firmware assumes
19YY when CB is clear and 20YY otherwise. Which means years 1900-1969
will be shown as 2100-2169 in Linux. I think this is a feature rather
than a problem. The firmware does not set the CEB bit itself and does not
care of what its state is.
Cc: Alessandro Zummo <a.zummo@xxxxxxxxxxxx>
Cc: Herbert Valerio Riedel <hvr@xxxxxxx>
Cc: David Brownell <david-b@xxxxxxxxxxx>
Signed-off-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx>
---
drivers/rtc/rtc-m41t80.c | 18 +++++++++++++++---
1 file changed, 15 insertions(+), 3 deletions(-)
diff -puN drivers/rtc/rtc-m41t80.c~rtc-m41t80-century-bit-support drivers/rtc/rtc-m41t80.c
--- a/drivers/rtc/rtc-m41t80.c~rtc-m41t80-century-bit-support
+++ a/drivers/rtc/rtc-m41t80.c
@@ -50,6 +50,8 @@
(M41T80_REG_ALARM_SEC + 1 - M41T80_REG_ALARM_MON)
#define M41T80_SEC_ST (1 << 7) /* ST: Stop Bit */
+#define M41T80_HOUR_CEB (1 << 7) /* CEB: Century Enable Bit */
+#define M41T80_HOUR_CB (1 << 6) /* CB: Century Bit */
#define M41T80_ALMON_AFE (1 << 7) /* AFE: AF Enable Bit */
#define M41T80_ALMON_SQWE (1 << 6) /* SQWE: SQW Enable Bit */
#define M41T80_ALHOUR_HT (1 << 6) /* HT: Halt Update Bit */
@@ -110,8 +112,12 @@ static int m41t80_get_datetime(struct i2
tm->tm_wday = buf[M41T80_REG_WDAY] & 0x07;
tm->tm_mon = BCD2BIN(buf[M41T80_REG_MON] & 0x1f) - 1;
- /* assume 20YY not 19YY, and ignore the Century Bit */
- tm->tm_year = BCD2BIN(buf[M41T80_REG_YEAR]) + 100;
+ /* Assume 1970-2169, taking the Century Bit into account. */
+ tm->tm_year = BCD2BIN(buf[M41T80_REG_YEAR]);
+ if ((buf[M41T80_REG_HOUR] & M41T80_HOUR_CB) != 0)
+ tm->tm_year += 100;
+ if (tm->tm_year < 70)
+ tm->tm_year += 200;
return 0;
}
@@ -165,8 +171,14 @@ static int m41t80_set_datetime(struct i2
BIN2BCD(tm->tm_mday) | (buf[M41T80_REG_DAY] & ~0x3f);
buf[M41T80_REG_MON] =
BIN2BCD(tm->tm_mon + 1) | (buf[M41T80_REG_MON] & ~0x1f);
- /* assume 20YY not 19YY */
+ /* Assume 1970-2169 and set the Century Bit for 19YY/21YY. */
buf[M41T80_REG_YEAR] = BIN2BCD(tm->tm_year % 100);
+ if ((tm->tm_year / 100) % 2 != 0)
+ buf[M41T80_REG_HOUR] |= M41T80_HOUR_CB;
+ else
+ buf[M41T80_REG_HOUR] &= ~M41T80_HOUR_CB;
+ /* Enable toggling of the Century Bit at the end of a century. ;-) */
+ buf[M41T80_REG_HOUR] |= M41T80_HOUR_CEB;
if (i2c_transfer(client->adapter, msgs, 1) != 1) {
dev_err(&client->dev, "write error\n");
_
Patches currently in -mm which might be from macro@xxxxxxxxxxxxxx are
ntp-make-the-rtc-sync-mode-11-minute-again.patch
ntp-fix-calculation-of-the-next-jiffie-to-trigger-rtc-sync.patch
rtc-m41t80-sort-header-inclusions-for-readability.patch
rtc-m41t80-use-pr_info-as-appropriate.patch
rtc-m41t80-century-bit-support.patch
--
To unsubscribe from this list: send the line "unsubscribe mm-commits" in
the body of a message to majordomo@xxxxxxxxxxxxxxx
More majordomo info at http://vger.kernel.org/majordomo-info.html
