From 16486d0c1c659d4ab502c5bea408654287edcb74 Mon Sep 17 00:00:00 2001 From: Fabien Lahoudere Date: Wed, 5 Jul 2017 10:02:29 +0200 Subject: 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 Signed-off-by: Alexandre Belloni --- drivers/rtc/rtc-s35390a.c | 72 +++++++++++++++++++++++++++-------------------- 1 file changed, 42 insertions(+), 30 deletions(-) diff --git a/drivers/rtc/rtc-s35390a.c b/drivers/rtc/rtc-s35390a.c index 449820eeefe8..3aec3b225bc4 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 @@ 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); -- cgit