lkml.org 
[lkml]   [2016]   [Feb]   [9]   [last100]   RSS Feed
Views: [wrap][no wrap]   [headers]  [forward] 
 
Messages in this thread
Patch in this message
/
From
Subject[PATCH v2 2/3] RTC/PCF85063: fix time/date reading
Date
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>
---
drivers/rtc/rtc-pcf85063.c | 7 +++++++
1 file changed, 7 insertions(+)

diff --git a/drivers/rtc/rtc-pcf85063.c b/drivers/rtc/rtc-pcf85063.c
index 7f9caee..e0343e6 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 */
--
2.7.0.rc3
\
 
 \ /
  Last update: 2016-02-09 12:21    [W:0.100 / U:32.512 seconds]
©2003-2020 Jasper Spaans|hosted at Digital Ocean and TransIP|Read the blog|Advertise on this site