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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>
hifive-unleashed-5.1
Fabien Lahoudere 2017-07-05 10:02:29 +02:00 committed by Alexandre Belloni
parent 5771a8c088
commit 16486d0c1c
1 changed files with 42 additions and 30 deletions
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72
drivers/rtc/rtc-s35390a.c
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@ -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 @@ initialize:
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);