[rtc-linux] [PATCH 1/2] RTC: s35390a: handle invalid RTC time
From: Fabien Lahoudere <hidden>
Date: 2017-01-12 10:43:49
Subsystem:
real time clock (rtc) subsystem, the rest · Maintainers:
Alexandre Belloni, Linus Torvalds
If RTC time have been altered by low voltage, we notify users that RTC time is invalid by returning -EINVAL. The RTC time needs to be set correctly to clear the invalid flag. If the RTC is not set before restarting, the information will be lost. Signed-off-by: Fabien Lahoudere <redacted> --- drivers/rtc/rtc-s35390a.c | 9 +++++++++ 1 file changed, 9 insertions(+)
diff --git a/drivers/rtc/rtc-s35390a.c b/drivers/rtc/rtc-s35390a.c
index 5dab466..ef4ada9 100644
--- a/drivers/rtc/rtc-s35390a.c
+++ b/drivers/rtc/rtc-s35390a.c@@ -62,6 +62,7 @@ struct s35390a { struct i2c_client *client[8]; struct rtc_device *rtc; int twentyfourhour; + int isinvalid; }; static int s35390a_set_reg(struct s35390a *s35390a, int reg, char *buf, int len)
@@ -135,6 +136,8 @@ static int s35390a_reset(struct s35390a *s35390a, char *status1) * The 24H bit is kept over reset, so set it already here. */ initialize: + /* set the RTC time as invalid */ + s35390a->isinvalid = 1; *status1 = S35390A_FLAG_24H; buf = S35390A_FLAG_RESET | S35390A_FLAG_24H; ret = s35390a_set_reg(s35390a, S35390A_CMD_STATUS1, &buf, 1);
@@ -221,6 +224,8 @@ static int s35390a_set_datetime(struct i2c_client *client, struct rtc_time *tm) buf[i] = bitrev8(buf[i]); err = s35390a_set_reg(s35390a, S35390A_CMD_TIME1, buf, sizeof(buf)); + if (err >= 0) + s35390a->isinvalid = 0; return err; }
@@ -231,6 +236,9 @@ static int s35390a_get_datetime(struct i2c_client *client, struct rtc_time *tm) char buf[7]; int i, err; + if (s35390a->isinvalid) + return -EINVAL; + err = s35390a_get_reg(s35390a, S35390A_CMD_TIME1, buf, sizeof(buf)); if (err < 0) return err;
@@ -418,6 +426,7 @@ static int s35390a_probe(struct i2c_client *client, s35390a->client[0] = client; i2c_set_clientdata(client, s35390a); + s35390a->isinvalid = 0; /* This chip uses multiple addresses, use dummy devices for them */ for (i = 1; i < 8; ++i) {
--
1.8.3.1
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