[rtc-linux] [PATCH v2 0/2] RTC: s35390a: Improve low voltage or invalid time detection

[rtc-linux] [PATCH v2 0/2] RTC: s35390a: Improve low voltage or invalid time detection

[Fabien Lahoudere]

This patchset implements feature to detect RTC low voltage or power off.

Changes since v1:
	- Read register instead setting flags

Fabien Lahoudere (2):
  RTC: s35390a: handle invalid RTC time
  RTC: s35390a: implement ioctls

 drivers/rtc/rtc-s35390a.c | 104 ++++++++++++++++++++++++++++++++--------------
 1 file changed, 73 insertions(+), 31 deletions(-)

-- 
1.8.3.1

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[rtc-linux] [PATCH v2 1/2] RTC: s35390a: handle invalid RTC time

[Fabien Lahoudere]

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 <fabien.lahoudere@collabora.co.uk>
---
 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 5dab466..5ebb132 100644
--- a/drivers/rtc/rtc-s35390a.c
+++ b/drivers/rtc/rtc-s35390a.c
@@ -99,33 +99,12 @@ 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
@@ -135,7 +114,6 @@ 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);
 
@@ -158,6 +136,34 @@ 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];
@@ -201,13 +207,16 @@ 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);
@@ -228,9 +237,12 @@ 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;
@@ -398,7 +410,7 @@ static int s35390a_rtc_set_time(struct device *dev, struct rtc_time *tm)
 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;
@@ -431,9 +443,9 @@ 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;
 	}
@@ -459,7 +471,7 @@ 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);
-- 
1.8.3.1

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[PATCH v2 1/2] RTC: s35390a: handle invalid RTC time

[Fabien Lahoudere]

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 <fabien.lahoudere@collabora.co.uk>
---
 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 5dab466..5ebb132 100644
--- a/drivers/rtc/rtc-s35390a.c
+++ b/drivers/rtc/rtc-s35390a.c
@@ -99,33 +99,12 @@ 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
@@ -135,7 +114,6 @@ 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);
 
@@ -158,6 +136,34 @@ 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];
@@ -201,13 +207,16 @@ 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);
@@ -228,9 +237,12 @@ 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;
@@ -398,7 +410,7 @@ static int s35390a_rtc_set_time(struct device *dev, struct rtc_time *tm)
 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;
@@ -431,9 +443,9 @@ 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;
 	}
@@ -459,7 +471,7 @@ 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);
-- 
1.8.3.1

[rtc-linux] [PATCH v2 2/2] RTC: s35390a: implement ioctls

[Fabien Lahoudere]

Implements RTC_VL_READ and RTC_VL_CLR ioctls.

Signed-off-by: Fabien Lahoudere <fabien.lahoudere@collabora.co.uk>
---
 drivers/rtc/rtc-s35390a.c | 32 +++++++++++++++++++++++++++++++-
 1 file changed, 31 insertions(+), 1 deletion(-)

diff --git a/drivers/rtc/rtc-s35390a.c b/drivers/rtc/rtc-s35390a.c
index 5ebb132..9261ba6 100644
--- a/drivers/rtc/rtc-s35390a.c
+++ b/drivers/rtc/rtc-s35390a.c
@@ -397,12 +397,42 @@ static int s35390a_rtc_set_time(struct device *dev, struct rtc_time *tm)
 	return s35390a_set_datetime(to_i2c_client(dev), tm);
 }
 
+static int s35390a_rtc_ioctl(struct device *dev, unsigned int cmd,
+			     unsigned long arg)
+{
+	struct i2c_client *client = to_i2c_client(dev);
+	struct s35390a *s35390a = i2c_get_clientdata(client);
+	char sts;
+	int err;
+
+	switch (cmd) {
+	case RTC_VL_READ:
+		/* s35390a_reset set lowvoltage flag and init RTC if needed */
+		err = s35390a_read_status(s35390a, &sts);
+		if (err < 0)
+			return err;
+		if (copy_to_user((void __user *)arg, &err, sizeof(int)))
+			return -EFAULT;
+		break;
+	case RTC_VL_CLR:
+		/* update flag and clear register */
+		err = s35390a_init(s35390a);
+		if (err < 0)
+			return err;
+		break;
+	default:
+		return -ENOIOCTLCMD;
+	}
+
+	return 0;
+}
+
 static const struct rtc_class_ops s35390a_rtc_ops = {
 	.read_time	= s35390a_rtc_read_time,
 	.set_time	= s35390a_rtc_set_time,
 	.set_alarm	= s35390a_rtc_set_alarm,
 	.read_alarm	= s35390a_rtc_read_alarm,
-
+	.ioctl          = s35390a_rtc_ioctl,
 };
 
 static struct i2c_driver s35390a_driver;
-- 
1.8.3.1

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[PATCH v2 2/2] RTC: s35390a: implement ioctls

[Fabien Lahoudere]

Implements RTC_VL_READ and RTC_VL_CLR ioctls.

Signed-off-by: Fabien Lahoudere <fabien.lahoudere@collabora.co.uk>
---
 drivers/rtc/rtc-s35390a.c | 32 +++++++++++++++++++++++++++++++-
 1 file changed, 31 insertions(+), 1 deletion(-)

diff --git a/drivers/rtc/rtc-s35390a.c b/drivers/rtc/rtc-s35390a.c
index 5ebb132..9261ba6 100644
--- a/drivers/rtc/rtc-s35390a.c
+++ b/drivers/rtc/rtc-s35390a.c
@@ -397,12 +397,42 @@ static int s35390a_rtc_set_time(struct device *dev, struct rtc_time *tm)
 	return s35390a_set_datetime(to_i2c_client(dev), tm);
 }
 
+static int s35390a_rtc_ioctl(struct device *dev, unsigned int cmd,
+			     unsigned long arg)
+{
+	struct i2c_client *client = to_i2c_client(dev);
+	struct s35390a *s35390a = i2c_get_clientdata(client);
+	char sts;
+	int err;
+
+	switch (cmd) {
+	case RTC_VL_READ:
+		/* s35390a_reset set lowvoltage flag and init RTC if needed */
+		err = s35390a_read_status(s35390a, &sts);
+		if (err < 0)
+			return err;
+		if (copy_to_user((void __user *)arg, &err, sizeof(int)))
+			return -EFAULT;
+		break;
+	case RTC_VL_CLR:
+		/* update flag and clear register */
+		err = s35390a_init(s35390a);
+		if (err < 0)
+			return err;
+		break;
+	default:
+		return -ENOIOCTLCMD;
+	}
+
+	return 0;
+}
+
 static const struct rtc_class_ops s35390a_rtc_ops = {
 	.read_time	= s35390a_rtc_read_time,
 	.set_time	= s35390a_rtc_set_time,
 	.set_alarm	= s35390a_rtc_set_alarm,
 	.read_alarm	= s35390a_rtc_read_alarm,
-
+	.ioctl          = s35390a_rtc_ioctl,
 };
 
 static struct i2c_driver s35390a_driver;
-- 
1.8.3.1

[rtc-linux] Re: [PATCH v2 1/2] RTC: s35390a: handle invalid RTC time

[Alexandre Belloni]

On 05/07/2017 at 10:02:29 +0200, Fabien Lahoudere wrote:
> 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 <fabien.lahoudere@collabora.co.uk>
> ---
>  drivers/rtc/rtc-s35390a.c | 72 +++++++++++++++++++++++++++--------------------
>  1 file changed, 42 insertions(+), 30 deletions(-)
> 
Applied, thanks.

-- 
Alexandre Belloni, Free Electrons
Embedded Linux and Kernel engineering
http://free-electrons.com

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[rtc-linux] Re: [PATCH v2 2/2] RTC: s35390a: implement ioctls

[Alexandre Belloni]

On 05/07/2017 at 10:02:30 +0200, Fabien Lahoudere wrote:
> Implements RTC_VL_READ and RTC_VL_CLR ioctls.
> 
> Signed-off-by: Fabien Lahoudere <fabien.lahoudere@collabora.co.uk>
> ---
>  drivers/rtc/rtc-s35390a.c | 32 +++++++++++++++++++++++++++++++-
>  1 file changed, 31 insertions(+), 1 deletion(-)
> 
Applied, thanks.

-- 
Alexandre Belloni, Free Electrons
Embedded Linux and Kernel engineering
http://free-electrons.com

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