Commit 16486d0c authored by Fabien Lahoudere's avatar Fabien Lahoudere Committed by Alexandre Belloni
Browse files

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: default avatarFabien Lahoudere <fabien.lahoudere@collabora.co.uk>
Signed-off-by: default avatarAlexandre Belloni <alexandre.belloni@free-electrons.com>
parent 5771a8c0

drivers/rtc/rtc-s35390a.c

+42 −30
Original line number Diff line number Diff line
@@ -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);

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