rtc: s35390a: handle invalid RTC time
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.
Signed-off-by: Fabien Lahoudere <fabien.lahoudere@collabora.co.uk>
Signed-off-by: Alexandre Belloni <alexandre.belloni@free-electrons.com>
diff --git a/drivers/rtc/rtc-s35390a.c b/drivers/rtc/rtc-s35390a.c
index 449820e..3aec3b2 100644
--- a/drivers/rtc/rtc-s35390a.c
+++ b/drivers/rtc/rtc-s35390a.c
@@ -106,33 +106,12 @@ static int s35390a_get_reg(struct s35390a *s35390a, int reg, char *buf, int len)
return 0;
}
-/*
- * Returns <0 on error, 0 if rtc is setup fine and 1 if the chip was reset.
- * To keep the information if an irq is pending, pass the value read from
- * STATUS1 to the caller.
- */
-static int s35390a_reset(struct s35390a *s35390a, char *status1)
+static int s35390a_init(struct s35390a *s35390a)
{
char buf;
int ret;
unsigned initcount = 0;
- ret = s35390a_get_reg(s35390a, S35390A_CMD_STATUS1, status1, 1);
- if (ret < 0)
- return ret;
-
- if (*status1 & S35390A_FLAG_POC)
- /*
- * Do not communicate for 0.5 seconds since the power-on
- * detection circuit is in operation.
- */
- msleep(500);
- else if (!(*status1 & S35390A_FLAG_BLD))
- /*
- * If both POC and BLD are unset everything is fine.
- */
- return 0;
-
/*
* At least one of POC and BLD are set, so reinitialise chip. Keeping
* this information in the hardware to know later that the time isn't
@@ -142,7 +121,6 @@ static int s35390a_reset(struct s35390a *s35390a, char *status1)
* The 24H bit is kept over reset, so set it already here.
*/
initialize:
- *status1 = S35390A_FLAG_24H;
buf = S35390A_FLAG_RESET | S35390A_FLAG_24H;
ret = s35390a_set_reg(s35390a, S35390A_CMD_STATUS1, &buf, 1);
@@ -165,6 +143,34 @@ static int s35390a_reset(struct s35390a *s35390a, char *status1)
return 1;
}
+/*
+ * Returns <0 on error, 0 if rtc is setup fine and 1 if the chip was reset.
+ * To keep the information if an irq is pending, pass the value read from
+ * STATUS1 to the caller.
+ */
+static int s35390a_read_status(struct s35390a *s35390a, char *status1)
+{
+ int ret;
+
+ ret = s35390a_get_reg(s35390a, S35390A_CMD_STATUS1, status1, 1);
+ if (ret < 0)
+ return ret;
+
+ if (*status1 & S35390A_FLAG_POC) {
+ /*
+ * Do not communicate for 0.5 seconds since the power-on
+ * detection circuit is in operation.
+ */
+ msleep(500);
+ return 1;
+ } else if (*status1 & S35390A_FLAG_BLD)
+ return 1;
+ /*
+ * If both POC and BLD are unset everything is fine.
+ */
+ return 0;
+}
+
static int s35390a_disable_test_mode(struct s35390a *s35390a)
{
char buf[1];
@@ -208,13 +214,16 @@ static int s35390a_set_datetime(struct i2c_client *client, struct rtc_time *tm)
{
struct s35390a *s35390a = i2c_get_clientdata(client);
int i, err;
- char buf[7];
+ char buf[7], status;
dev_dbg(&client->dev, "%s: tm is secs=%d, mins=%d, hours=%d mday=%d, "
"mon=%d, year=%d, wday=%d\n", __func__, tm->tm_sec,
tm->tm_min, tm->tm_hour, tm->tm_mday, tm->tm_mon, tm->tm_year,
tm->tm_wday);
+ if (s35390a_read_status(s35390a, &status) == 1)
+ s35390a_init(s35390a);
+
buf[S35390A_BYTE_YEAR] = bin2bcd(tm->tm_year - 100);
buf[S35390A_BYTE_MONTH] = bin2bcd(tm->tm_mon + 1);
buf[S35390A_BYTE_DAY] = bin2bcd(tm->tm_mday);
@@ -235,9 +244,12 @@ static int s35390a_set_datetime(struct i2c_client *client, struct rtc_time *tm)
static int s35390a_get_datetime(struct i2c_client *client, struct rtc_time *tm)
{
struct s35390a *s35390a = i2c_get_clientdata(client);
- char buf[7];
+ char buf[7], status;
int i, err;
+ if (s35390a_read_status(s35390a, &status) == 1)
+ return -EINVAL;
+
err = s35390a_get_reg(s35390a, S35390A_CMD_TIME1, buf, sizeof(buf));
if (err < 0)
return err;
@@ -405,7 +417,7 @@ static struct i2c_driver s35390a_driver;
static int s35390a_probe(struct i2c_client *client,
const struct i2c_device_id *id)
{
- int err, err_reset;
+ int err, err_read;
unsigned int i;
struct s35390a *s35390a;
struct rtc_time tm;
@@ -438,9 +450,9 @@ static int s35390a_probe(struct i2c_client *client,
}
}
- err_reset = s35390a_reset(s35390a, &status1);
- if (err_reset < 0) {
- err = err_reset;
+ err_read = s35390a_read_status(s35390a, &status1);
+ if (err_read < 0) {
+ err = err_read;
dev_err(&client->dev, "error resetting chip\n");
goto exit_dummy;
}
@@ -466,7 +478,7 @@ static int s35390a_probe(struct i2c_client *client,
}
}
- if (err_reset > 0 || s35390a_get_datetime(client, &tm) < 0)
+ if (err_read > 0 || s35390a_get_datetime(client, &tm) < 0)
dev_warn(&client->dev, "clock needs to be set\n");
device_set_wakeup_capable(&client->dev, 1);