5.4-stable review patch. If anyone has any objections, please let me know.
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From: Meagan Lloyd meaganlloyd@linux.microsoft.com
[ Upstream commit 48458654659c9c2e149c211d86637f1592470da5 ]
In using CONFIG_RTC_HCTOSYS, rtc_hctosys() will sync the RTC time to the kernel time as long as rtc_read_time() succeeds. In some power loss situations, our supercapacitor-backed DS1342 RTC comes up with either an unpredictable future time or the default 01/01/00 from the datasheet. The oscillator stop flag (OSF) is set in these scenarios due to the power loss and can be used to determine the validity of the RTC data.
Some chip types in the ds1307 driver already have OSF handling to determine whether .read_time provides valid RTC data or returns -EINVAL.
This change removes the clear of the OSF in .probe as the OSF needs to be preserved to expand the OSF handling to the ds1341 chip type (note that DS1341 and DS1342 share a datasheet).
Signed-off-by: Meagan Lloyd meaganlloyd@linux.microsoft.com Reviewed-by: Tyler Hicks code@tyhicks.com Acked-by: Rodolfo Giometti giometti@enneenne.com Link: https://lore.kernel.org/r/1749665656-30108-2-git-send-email-meaganlloyd@linu... Signed-off-by: Alexandre Belloni alexandre.belloni@bootlin.com Signed-off-by: Sasha Levin sashal@kernel.org --- drivers/rtc/rtc-ds1307.c | 4 +--- 1 file changed, 1 insertion(+), 3 deletions(-)
diff --git a/drivers/rtc/rtc-ds1307.c b/drivers/rtc/rtc-ds1307.c index b371d1e48942..ff9785ff36e7 100644 --- a/drivers/rtc/rtc-ds1307.c +++ b/drivers/rtc/rtc-ds1307.c @@ -1686,10 +1686,8 @@ static int ds1307_probe(struct i2c_client *client, regmap_write(ds1307->regmap, DS1337_REG_CONTROL, regs[0]);
- /* oscillator fault? clear flag, and warn */ + /* oscillator fault? warn */ if (regs[1] & DS1337_BIT_OSF) { - regmap_write(ds1307->regmap, DS1337_REG_STATUS, - regs[1] & ~DS1337_BIT_OSF); dev_warn(ds1307->dev, "SET TIME!\n"); } break;