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authorJuergen Borleis <jbe@pengutronix.de>2016-02-09 11:57:26 +0100
committerAlexandre Belloni <alexandre.belloni@free-electrons.com>2016-03-14 17:08:17 +0100
commit6cc4c8b1e3790c63b2e1b6d9b25d2bda6e406572 (patch)
treeacabf4ff6d12954bb5c4d741cef57d1fd3e83d7a /drivers/rtc/rtc-pcf85063.c
parent7b5768486a910532885f01b9d2dad4818c8b3be1 (diff)
rtc: pcf85063: fix time/date reading
Check if the RTC signals an invalid time/date (due to a battery power loss for example). In this case ignore the time/date until it is really set again. Signed-off-by: Juergen Borleis <jbe@pengutronix.de> Signed-off-by: Alexandre Belloni <alexandre.belloni@free-electrons.com>
Diffstat (limited to 'drivers/rtc/rtc-pcf85063.c')
-rw-r--r--drivers/rtc/rtc-pcf85063.c7
1 files changed, 7 insertions, 0 deletions
diff --git a/drivers/rtc/rtc-pcf85063.c b/drivers/rtc/rtc-pcf85063.c
index 7f9caee5f4ab..e0343e6aeb31 100644
--- a/drivers/rtc/rtc-pcf85063.c
+++ b/drivers/rtc/rtc-pcf85063.c
@@ -22,6 +22,7 @@
#define PCF85063_REG_CTRL2 0x01
#define PCF85063_REG_SC 0x04 /* datetime */
+#define PCF85063_REG_SC_OS 0x80
#define PCF85063_REG_MN 0x05
#define PCF85063_REG_HR 0x06
#define PCF85063_REG_DM 0x07
@@ -62,6 +63,12 @@ static int pcf85063_get_datetime(struct i2c_client *client, struct rtc_time *tm)
return -EIO;
}
+ /* if the clock has lost its power it makes no sense to use its time */
+ if (regs[0] & PCF85063_REG_SC_OS) {
+ dev_warn(&client->dev, "Power loss detected, invalid time\n");
+ return -EINVAL;
+ }
+
tm->tm_sec = bcd2bin(regs[0] & 0x7F);
tm->tm_min = bcd2bin(regs[1] & 0x7F);
tm->tm_hour = bcd2bin(regs[2] & 0x3F); /* rtc hr 0-23 */