rtc: ds1307: fix century bit support
Add an option to properly support the century bit of ds1337 and compatibles and ds1340. Because the driver had a bug until now, it is not possible to switch users to the fixed code directly as RTCs in the field will wrongly have the century bit set. Acked-by: Arnaud Ebalard <arno@natisbad.org> Signed-off-by: Alexandre Belloni <alexandre.belloni@free-electrons.com>
This commit is contained in:
parent
59e5e70c95
commit
50d6c0ea81
|
@ -234,6 +234,20 @@ config RTC_DRV_DS1307_HWMON
|
|||
Say Y here if you want to expose temperature sensor data on
|
||||
rtc-ds1307 (only DS3231)
|
||||
|
||||
config RTC_DRV_DS1307_CENTURY
|
||||
bool "Century bit support for rtc-ds1307"
|
||||
depends on RTC_DRV_DS1307
|
||||
default n
|
||||
help
|
||||
The DS1307 driver suffered from a bug where it was enabling the
|
||||
century bit inconditionnally but never used it when reading the time.
|
||||
It made the driver unable to support dates beyond 2099.
|
||||
Setting this option will add proper support for the century bit but if
|
||||
the time was previously set using a kernel predating this option,
|
||||
reading the date will return a date in the next century.
|
||||
To solve that, you could boot a kernel without this option set, set
|
||||
the RTC date and then boot a kernel with this option set.
|
||||
|
||||
config RTC_DRV_DS1374
|
||||
tristate "Dallas/Maxim DS1374"
|
||||
help
|
||||
|
|
|
@ -382,10 +382,25 @@ static int ds1307_get_time(struct device *dev, struct rtc_time *t)
|
|||
t->tm_mday = bcd2bin(ds1307->regs[DS1307_REG_MDAY] & 0x3f);
|
||||
tmp = ds1307->regs[DS1307_REG_MONTH] & 0x1f;
|
||||
t->tm_mon = bcd2bin(tmp) - 1;
|
||||
|
||||
/* assume 20YY not 19YY, and ignore DS1337_BIT_CENTURY */
|
||||
t->tm_year = bcd2bin(ds1307->regs[DS1307_REG_YEAR]) + 100;
|
||||
|
||||
#ifdef CONFIG_RTC_DRV_DS1307_CENTURY
|
||||
switch (ds1307->type) {
|
||||
case ds_1337:
|
||||
case ds_1339:
|
||||
case ds_3231:
|
||||
if (ds1307->regs[DS1307_REG_MONTH] & DS1337_BIT_CENTURY)
|
||||
t->tm_year += 100;
|
||||
break;
|
||||
case ds_1340:
|
||||
if (ds1307->regs[DS1307_REG_HOUR] & DS1340_BIT_CENTURY)
|
||||
t->tm_year += 100;
|
||||
break;
|
||||
default:
|
||||
break;
|
||||
}
|
||||
#endif
|
||||
|
||||
dev_dbg(dev, "%s secs=%d, mins=%d, "
|
||||
"hours=%d, mday=%d, mon=%d, year=%d, wday=%d\n",
|
||||
"read", t->tm_sec, t->tm_min,
|
||||
|
@ -409,6 +424,27 @@ static int ds1307_set_time(struct device *dev, struct rtc_time *t)
|
|||
t->tm_hour, t->tm_mday,
|
||||
t->tm_mon, t->tm_year, t->tm_wday);
|
||||
|
||||
#ifdef CONFIG_RTC_DRV_DS1307_CENTURY
|
||||
if (t->tm_year < 100)
|
||||
return -EINVAL;
|
||||
|
||||
switch (ds1307->type) {
|
||||
case ds_1337:
|
||||
case ds_1339:
|
||||
case ds_3231:
|
||||
case ds_1340:
|
||||
if (t->tm_year > 299)
|
||||
return -EINVAL;
|
||||
default:
|
||||
if (t->tm_year > 199)
|
||||
return -EINVAL;
|
||||
break;
|
||||
}
|
||||
#else
|
||||
if (t->tm_year < 100 || t->tm_year > 199)
|
||||
return -EINVAL;
|
||||
#endif
|
||||
|
||||
buf[DS1307_REG_SECS] = bin2bcd(t->tm_sec);
|
||||
buf[DS1307_REG_MIN] = bin2bcd(t->tm_min);
|
||||
buf[DS1307_REG_HOUR] = bin2bcd(t->tm_hour);
|
||||
|
@ -424,11 +460,13 @@ static int ds1307_set_time(struct device *dev, struct rtc_time *t)
|
|||
case ds_1337:
|
||||
case ds_1339:
|
||||
case ds_3231:
|
||||
if (t->tm_year > 199)
|
||||
buf[DS1307_REG_MONTH] |= DS1337_BIT_CENTURY;
|
||||
break;
|
||||
case ds_1340:
|
||||
buf[DS1307_REG_HOUR] |= DS1340_BIT_CENTURY_EN
|
||||
| DS1340_BIT_CENTURY;
|
||||
buf[DS1307_REG_HOUR] |= DS1340_BIT_CENTURY_EN;
|
||||
if (t->tm_year > 199)
|
||||
buf[DS1307_REG_HOUR] |= DS1340_BIT_CENTURY;
|
||||
break;
|
||||
case mcp794xx:
|
||||
/*
|
||||
|
|
Loading…
Reference in New Issue