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rtc: ds1307: fix century bit support

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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:
Alexandre Belloni
2016-07-13 02:26:08 +02:00
parent 59e5e70c95
commit 50d6c0ea81
2 changed files with 57 additions and 5 deletions
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48
drivers/rtc/rtc-ds1307.c
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@@ -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:
buf[DS1307_REG_MONTH] |= DS1337_BIT_CENTURY;
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:
/*