[rtc-linux] [PATCH 0/2] rtc: abx80x: Handle autocalibration and oscillator failure

[rtc-linux] [PATCH 0/2] rtc: abx80x: Handle autocalibration and oscillator failure

[Mylene JOSSERAND]

The current patches handle the autocalibration and the oscillator failure
for ABX80X RTC.
The autocalibration is handled using sysfs entries and the oscillator
failure bit is handled only for the XT Oscillator.

Mylene JOSSERAND (2):
  rtc: abx80x: handle autocalibration
  rtc: abx80x: handle the oscillator failure bit

 drivers/rtc/rtc-abx80x.c | 252 ++++++++++++++++++++++++++++++++++++++++++++++-
 1 file changed, 250 insertions(+), 2 deletions(-)

-- 
2.7.0

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[PATCH 0/2] rtc: abx80x: Handle autocalibration and oscillator failure

[Mylene JOSSERAND]

The current patches handle the autocalibration and the oscillator failure
for ABX80X RTC.
The autocalibration is handled using sysfs entries and the oscillator
failure bit is handled only for the XT Oscillator.

Mylene JOSSERAND (2):
  rtc: abx80x: handle autocalibration
  rtc: abx80x: handle the oscillator failure bit

 drivers/rtc/rtc-abx80x.c | 252 ++++++++++++++++++++++++++++++++++++++++++++++-
 1 file changed, 250 insertions(+), 2 deletions(-)

-- 
2.7.0

[rtc-linux] [PATCH 1/2] rtc: abx80x: handle autocalibration

[Mylene JOSSERAND]

The autocalibration is separated in two bits to set in Oscillator
Control register (0x1c) :
 - OSEL bit to select the oscillator type (XT or RC).
 - ACAL bit to select the autocalibration type.

These functionnalities are exported in sysfs entries : "oscillator"
and "autocalibration". Respectively, the values are "xtal" for XT
oscillator and "rc" for RC oscillator and 0 to disable the
autocalibration cycle, 512 for a 512 seconds autocalibration cycle
and 1024 for a cycle of 1024 seconds.

Examples :
Set to XT Oscillator
echo xtal > /sys/class/rtc/rtc0/device/oscillator
Activate an autocalibration every 512 seconds
echo 512 > /sys/class/rtc/rtc0/device/autocalibration

Signed-off-by: Mylene JOSSERAND <mylene.josserand@free-electrons.com>
---
 drivers/rtc/rtc-abx80x.c | 219 +++++++++++++++++++++++++++++++++++++++++++++++
 1 file changed, 219 insertions(+)

diff --git a/drivers/rtc/rtc-abx80x.c b/drivers/rtc/rtc-abx80x.c
index d41bbcd..0e4c9a0 100644
--- a/drivers/rtc/rtc-abx80x.c
+++ b/drivers/rtc/rtc-abx80x.c
@@ -49,7 +49,19 @@
 
 #define ABX8XX_REG_CD_TIMER_CTL	0x18
 
+#define ABX8XX_REG_OSC		0x1c
+#define ABX8XX_OSC_FOS		BIT(3)
+#define ABX8XX_OSC_BOS		BIT(4)
+#define ABX8XX_OSC_ACAL_512	BIT(5)
+#define ABX8XX_OSC_ACAL_1024	BIT(6)
+
+#define ABX8XX_OSC_OSEL		BIT(7)
+
+#define ABX8XX_REG_OSS		0x1d
+#define ABX8XX_OSS_OMODE	BIT(4)
+
 #define ABX8XX_REG_CFG_KEY	0x1f
+#define ABX8XX_CFG_KEY_OSC	0xa1
 #define ABX8XX_CFG_KEY_MISC	0x9d
 
 #define ABX8XX_REG_ID0		0x28
@@ -81,6 +93,20 @@ static struct abx80x_cap abx80x_caps[] = {
 	[ABX80X] = {.pn = 0}
 };
 
+static int abx80x_is_rc_mode(struct i2c_client *client)
+{
+	int flags = 0;
+
+	flags =  i2c_smbus_read_byte_data(client, ABX8XX_REG_OSS);
+	if (flags < 0) {
+		dev_err(&client->dev,
+			"Failed to read autocalibration attribute\n");
+		return flags;
+	}
+
+	return (flags & ABX8XX_OSS_OMODE) ? 1 : 0;
+}
+
 static int abx80x_enable_trickle_charger(struct i2c_client *client,
 					 u8 trickle_cfg)
 {
@@ -248,6 +274,174 @@ static int abx80x_set_alarm(struct device *dev, struct rtc_wkalrm *t)
 	return 0;
 }
 
+static int abx80x_rtc_set_autocalibration(struct device *dev,
+					  int autocalibration)
+{
+	struct i2c_client *client = to_i2c_client(dev);
+	int retval, flags = 0;
+
+	if ((autocalibration != 0) && (autocalibration != 1024) &&
+	    (autocalibration != 512)) {
+		dev_err(dev, "autocalibration value outside permitted range\n");
+		return -EINVAL;
+	}
+
+	flags = i2c_smbus_read_byte_data(client, ABX8XX_REG_OSC);
+	if (flags < 0)
+		return flags;
+
+	if (autocalibration == 0) {
+		flags &= ~(ABX8XX_OSC_ACAL_512 | ABX8XX_OSC_ACAL_1024);
+	} else if (autocalibration == 1024) {
+		/* 1024 autocalibration is 0x10 */
+		flags |= ABX8XX_OSC_ACAL_1024;
+		flags &= ~(ABX8XX_OSC_ACAL_512);
+	} else {
+		/* 512 autocalibration is 0x11 */
+		flags |= (ABX8XX_OSC_ACAL_1024 | ABX8XX_OSC_ACAL_512);
+	}
+
+	/* Unlock write access to Oscillator Control Register */
+	retval = i2c_smbus_write_byte_data(client, ABX8XX_REG_CFG_KEY,
+					   ABX8XX_CFG_KEY_OSC);
+	if (retval < 0) {
+		dev_err(dev, "Failed to write CONFIG_KEY register\n");
+		return retval;
+	}
+
+	retval = i2c_smbus_write_byte_data(client, ABX8XX_REG_OSC, flags);
+
+	return retval;
+}
+
+static int abx80x_rtc_get_autocalibration(struct device *dev)
+{
+	struct i2c_client *client = to_i2c_client(dev);
+	int flags = 0, autocalibration;
+
+	flags =  i2c_smbus_read_byte_data(client, ABX8XX_REG_OSC);
+	if (flags < 0)
+		return flags;
+
+	if (flags & ABX8XX_OSC_ACAL_512)
+		autocalibration = 512;
+	else if (flags & ABX8XX_OSC_ACAL_1024)
+		autocalibration = 1024;
+	else
+		autocalibration = 0;
+
+	return autocalibration;
+}
+
+static ssize_t autocalibration_store(struct device *dev,
+				     struct device_attribute *attr,
+				     const char *buf, size_t count)
+{
+	int retval;
+	unsigned long autocalibration = 0;
+
+	retval = kstrtoul(buf, 10, &autocalibration);
+	if (retval < 0) {
+		dev_err(dev, "Failed to store RTC autocalibration attribute\n");
+		return -EINVAL;
+	}
+
+	retval = abx80x_rtc_set_autocalibration(dev, autocalibration);
+
+	return retval ? retval : count;
+}
+
+static ssize_t autocalibration_show(struct device *dev,
+				    struct device_attribute *attr, char *buf)
+{
+	int autocalibration = 0;
+
+	autocalibration = abx80x_rtc_get_autocalibration(dev);
+	if (autocalibration < 0) {
+		dev_err(dev, "Failed to read RTC autocalibration\n");
+		sprintf(buf, "0\n");
+		return autocalibration;
+	}
+
+	return sprintf(buf, "%d\n", autocalibration);
+}
+
+static DEVICE_ATTR_RW(autocalibration);
+
+static ssize_t oscillator_store(struct device *dev,
+				struct device_attribute *attr,
+				const char *buf, size_t count)
+{
+	struct i2c_client *client = to_i2c_client(dev);
+	int retval, flags, rc_mode = 0;
+
+	if (strncmp(buf, "rc", 2) == 0) {
+		rc_mode = 1;
+	} else if (strncmp(buf, "xtal", 4) == 0) {
+		rc_mode = 0;
+	} else {
+		dev_err(dev, "Oscillator selection value outside permitted ones\n");
+		return -EINVAL;
+	}
+
+	flags =  i2c_smbus_read_byte_data(client, ABX8XX_REG_OSC);
+	if (flags < 0)
+		return flags;
+
+	if (rc_mode == 0)
+		flags &= ~(ABX8XX_OSC_OSEL);
+	else
+		flags |= (ABX8XX_OSC_OSEL);
+
+	/* Unlock write access on Oscillator Control register */
+	retval = i2c_smbus_write_byte_data(client, ABX8XX_REG_CFG_KEY,
+					   ABX8XX_CFG_KEY_OSC);
+	if (retval < 0) {
+		dev_err(dev, "Failed to write CONFIG_KEY register\n");
+		return retval;
+	}
+
+	retval = i2c_smbus_write_byte_data(client, ABX8XX_REG_OSC, flags);
+	if (retval < 0) {
+		dev_err(dev, "Failed to write Oscillator Control register\n");
+		return retval;
+	}
+
+	return retval ? retval : count;
+}
+
+static ssize_t oscillator_show(struct device *dev,
+			       struct device_attribute *attr, char *buf)
+{
+	int rc_mode = 0;
+	struct i2c_client *client = to_i2c_client(dev);
+
+	rc_mode = abx80x_is_rc_mode(client);
+
+	if (rc_mode < 0) {
+		dev_err(dev, "Failed to read RTC oscillator selection\n");
+		sprintf(buf, "\n");
+		return rc_mode;
+	}
+
+	if (rc_mode)
+		return sprintf(buf, "rc\n");
+	else
+		return sprintf(buf, "xtal\n");
+}
+
+static DEVICE_ATTR_RW(oscillator);
+
+static struct attribute *rtc_calib_attrs[] = {
+	&dev_attr_autocalibration.attr,
+	&dev_attr_oscillator.attr,
+	NULL,
+};
+
+static const struct attribute_group rtc_calib_attr_group = {
+	.attrs		= rtc_calib_attrs,
+};
+
 static int abx80x_alarm_irq_enable(struct device *dev, unsigned int enabled)
 {
 	struct i2c_client *client = to_i2c_client(dev);
@@ -303,6 +497,13 @@ static int abx80x_dt_trickle_cfg(struct device_node *np)
 	return (trickle_cfg | i);
 }
 
+static void rtc_calib_remove_sysfs_group(void *_dev)
+{
+	struct device *dev = _dev;
+
+	sysfs_remove_group(&dev->kobj, &rtc_calib_attr_group);
+}
+
 static int abx80x_probe(struct i2c_client *client,
 			const struct i2c_device_id *id)
 {
@@ -405,6 +606,24 @@ static int abx80x_probe(struct i2c_client *client,
 		}
 	}
 
+	/* Export sysfs entries */
+	err = sysfs_create_group(&(&client->dev)->kobj, &rtc_calib_attr_group);
+	if (err) {
+		dev_err(&client->dev, "Failed to create sysfs group: %d\n",
+			err);
+		return err;
+	}
+
+	err = devm_add_action(&client->dev, rtc_calib_remove_sysfs_group,
+			      &client->dev);
+	if (err) {
+		rtc_calib_remove_sysfs_group(&client->dev);
+		dev_err(&client->dev,
+			"Failed to add sysfs cleanup action: %d\n",
+			err);
+		return err;
+	}
+
 	return 0;
 }
 
-- 
2.7.0

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[PATCH 1/2] rtc: abx80x: handle autocalibration

[Mylene JOSSERAND]

The autocalibration is separated in two bits to set in Oscillator
Control register (0x1c) :
 - OSEL bit to select the oscillator type (XT or RC).
 - ACAL bit to select the autocalibration type.

These functionnalities are exported in sysfs entries : "oscillator"
and "autocalibration". Respectively, the values are "xtal" for XT
oscillator and "rc" for RC oscillator and 0 to disable the
autocalibration cycle, 512 for a 512 seconds autocalibration cycle
and 1024 for a cycle of 1024 seconds.

Examples :
Set to XT Oscillator
echo xtal > /sys/class/rtc/rtc0/device/oscillator
Activate an autocalibration every 512 seconds
echo 512 > /sys/class/rtc/rtc0/device/autocalibration

Signed-off-by: Mylene JOSSERAND <mylene.josserand@free-electrons.com>
---
 drivers/rtc/rtc-abx80x.c | 219 +++++++++++++++++++++++++++++++++++++++++++++++
 1 file changed, 219 insertions(+)

diff --git a/drivers/rtc/rtc-abx80x.c b/drivers/rtc/rtc-abx80x.c
index d41bbcd..0e4c9a0 100644
--- a/drivers/rtc/rtc-abx80x.c
+++ b/drivers/rtc/rtc-abx80x.c
@@ -49,7 +49,19 @@
 
 #define ABX8XX_REG_CD_TIMER_CTL	0x18
 
+#define ABX8XX_REG_OSC		0x1c
+#define ABX8XX_OSC_FOS		BIT(3)
+#define ABX8XX_OSC_BOS		BIT(4)
+#define ABX8XX_OSC_ACAL_512	BIT(5)
+#define ABX8XX_OSC_ACAL_1024	BIT(6)
+
+#define ABX8XX_OSC_OSEL		BIT(7)
+
+#define ABX8XX_REG_OSS		0x1d
+#define ABX8XX_OSS_OMODE	BIT(4)
+
 #define ABX8XX_REG_CFG_KEY	0x1f
+#define ABX8XX_CFG_KEY_OSC	0xa1
 #define ABX8XX_CFG_KEY_MISC	0x9d
 
 #define ABX8XX_REG_ID0		0x28
@@ -81,6 +93,20 @@ static struct abx80x_cap abx80x_caps[] = {
 	[ABX80X] = {.pn = 0}
 };
 
+static int abx80x_is_rc_mode(struct i2c_client *client)
+{
+	int flags = 0;
+
+	flags =  i2c_smbus_read_byte_data(client, ABX8XX_REG_OSS);
+	if (flags < 0) {
+		dev_err(&client->dev,
+			"Failed to read autocalibration attribute\n");
+		return flags;
+	}
+
+	return (flags & ABX8XX_OSS_OMODE) ? 1 : 0;
+}
+
 static int abx80x_enable_trickle_charger(struct i2c_client *client,
 					 u8 trickle_cfg)
 {
@@ -248,6 +274,174 @@ static int abx80x_set_alarm(struct device *dev, struct rtc_wkalrm *t)
 	return 0;
 }
 
+static int abx80x_rtc_set_autocalibration(struct device *dev,
+					  int autocalibration)
+{
+	struct i2c_client *client = to_i2c_client(dev);
+	int retval, flags = 0;
+
+	if ((autocalibration != 0) && (autocalibration != 1024) &&
+	    (autocalibration != 512)) {
+		dev_err(dev, "autocalibration value outside permitted range\n");
+		return -EINVAL;
+	}
+
+	flags = i2c_smbus_read_byte_data(client, ABX8XX_REG_OSC);
+	if (flags < 0)
+		return flags;
+
+	if (autocalibration == 0) {
+		flags &= ~(ABX8XX_OSC_ACAL_512 | ABX8XX_OSC_ACAL_1024);
+	} else if (autocalibration == 1024) {
+		/* 1024 autocalibration is 0x10 */
+		flags |= ABX8XX_OSC_ACAL_1024;
+		flags &= ~(ABX8XX_OSC_ACAL_512);
+	} else {
+		/* 512 autocalibration is 0x11 */
+		flags |= (ABX8XX_OSC_ACAL_1024 | ABX8XX_OSC_ACAL_512);
+	}
+
+	/* Unlock write access to Oscillator Control Register */
+	retval = i2c_smbus_write_byte_data(client, ABX8XX_REG_CFG_KEY,
+					   ABX8XX_CFG_KEY_OSC);
+	if (retval < 0) {
+		dev_err(dev, "Failed to write CONFIG_KEY register\n");
+		return retval;
+	}
+
+	retval = i2c_smbus_write_byte_data(client, ABX8XX_REG_OSC, flags);
+
+	return retval;
+}
+
+static int abx80x_rtc_get_autocalibration(struct device *dev)
+{
+	struct i2c_client *client = to_i2c_client(dev);
+	int flags = 0, autocalibration;
+
+	flags =  i2c_smbus_read_byte_data(client, ABX8XX_REG_OSC);
+	if (flags < 0)
+		return flags;
+
+	if (flags & ABX8XX_OSC_ACAL_512)
+		autocalibration = 512;
+	else if (flags & ABX8XX_OSC_ACAL_1024)
+		autocalibration = 1024;
+	else
+		autocalibration = 0;
+
+	return autocalibration;
+}
+
+static ssize_t autocalibration_store(struct device *dev,
+				     struct device_attribute *attr,
+				     const char *buf, size_t count)
+{
+	int retval;
+	unsigned long autocalibration = 0;
+
+	retval = kstrtoul(buf, 10, &autocalibration);
+	if (retval < 0) {
+		dev_err(dev, "Failed to store RTC autocalibration attribute\n");
+		return -EINVAL;
+	}
+
+	retval = abx80x_rtc_set_autocalibration(dev, autocalibration);
+
+	return retval ? retval : count;
+}
+
+static ssize_t autocalibration_show(struct device *dev,
+				    struct device_attribute *attr, char *buf)
+{
+	int autocalibration = 0;
+
+	autocalibration = abx80x_rtc_get_autocalibration(dev);
+	if (autocalibration < 0) {
+		dev_err(dev, "Failed to read RTC autocalibration\n");
+		sprintf(buf, "0\n");
+		return autocalibration;
+	}
+
+	return sprintf(buf, "%d\n", autocalibration);
+}
+
+static DEVICE_ATTR_RW(autocalibration);
+
+static ssize_t oscillator_store(struct device *dev,
+				struct device_attribute *attr,
+				const char *buf, size_t count)
+{
+	struct i2c_client *client = to_i2c_client(dev);
+	int retval, flags, rc_mode = 0;
+
+	if (strncmp(buf, "rc", 2) == 0) {
+		rc_mode = 1;
+	} else if (strncmp(buf, "xtal", 4) == 0) {
+		rc_mode = 0;
+	} else {
+		dev_err(dev, "Oscillator selection value outside permitted ones\n");
+		return -EINVAL;
+	}
+
+	flags =  i2c_smbus_read_byte_data(client, ABX8XX_REG_OSC);
+	if (flags < 0)
+		return flags;
+
+	if (rc_mode == 0)
+		flags &= ~(ABX8XX_OSC_OSEL);
+	else
+		flags |= (ABX8XX_OSC_OSEL);
+
+	/* Unlock write access on Oscillator Control register */
+	retval = i2c_smbus_write_byte_data(client, ABX8XX_REG_CFG_KEY,
+					   ABX8XX_CFG_KEY_OSC);
+	if (retval < 0) {
+		dev_err(dev, "Failed to write CONFIG_KEY register\n");
+		return retval;
+	}
+
+	retval = i2c_smbus_write_byte_data(client, ABX8XX_REG_OSC, flags);
+	if (retval < 0) {
+		dev_err(dev, "Failed to write Oscillator Control register\n");
+		return retval;
+	}
+
+	return retval ? retval : count;
+}
+
+static ssize_t oscillator_show(struct device *dev,
+			       struct device_attribute *attr, char *buf)
+{
+	int rc_mode = 0;
+	struct i2c_client *client = to_i2c_client(dev);
+
+	rc_mode = abx80x_is_rc_mode(client);
+
+	if (rc_mode < 0) {
+		dev_err(dev, "Failed to read RTC oscillator selection\n");
+		sprintf(buf, "\n");
+		return rc_mode;
+	}
+
+	if (rc_mode)
+		return sprintf(buf, "rc\n");
+	else
+		return sprintf(buf, "xtal\n");
+}
+
+static DEVICE_ATTR_RW(oscillator);
+
+static struct attribute *rtc_calib_attrs[] = {
+	&dev_attr_autocalibration.attr,
+	&dev_attr_oscillator.attr,
+	NULL,
+};
+
+static const struct attribute_group rtc_calib_attr_group = {
+	.attrs		= rtc_calib_attrs,
+};
+
 static int abx80x_alarm_irq_enable(struct device *dev, unsigned int enabled)
 {
 	struct i2c_client *client = to_i2c_client(dev);
@@ -303,6 +497,13 @@ static int abx80x_dt_trickle_cfg(struct device_node *np)
 	return (trickle_cfg | i);
 }
 
+static void rtc_calib_remove_sysfs_group(void *_dev)
+{
+	struct device *dev = _dev;
+
+	sysfs_remove_group(&dev->kobj, &rtc_calib_attr_group);
+}
+
 static int abx80x_probe(struct i2c_client *client,
 			const struct i2c_device_id *id)
 {
@@ -405,6 +606,24 @@ static int abx80x_probe(struct i2c_client *client,
 		}
 	}
 
+	/* Export sysfs entries */
+	err = sysfs_create_group(&(&client->dev)->kobj, &rtc_calib_attr_group);
+	if (err) {
+		dev_err(&client->dev, "Failed to create sysfs group: %d\n",
+			err);
+		return err;
+	}
+
+	err = devm_add_action(&client->dev, rtc_calib_remove_sysfs_group,
+			      &client->dev);
+	if (err) {
+		rtc_calib_remove_sysfs_group(&client->dev);
+		dev_err(&client->dev,
+			"Failed to add sysfs cleanup action: %d\n",
+			err);
+		return err;
+	}
+
 	return 0;
 }
 
-- 
2.7.0

[rtc-linux] [PATCH 2/2] rtc: abx80x: handle the oscillator failure bit

[Mylene JOSSERAND]

Handle the Oscillator Failure ('OF') bit from Oscillator Status register
(0x1D). This bit is cleared on set_time function and is read each time the
date/time is read, but only in case of XT Oscillator selection.
In RC mode, this bit is always set.

Signed-off-by: Mylene JOSSERAND <mylene.josserand@free-electrons.com>
---
 drivers/rtc/rtc-abx80x.c | 33 +++++++++++++++++++++++++++++++--
 1 file changed, 31 insertions(+), 2 deletions(-)

diff --git a/drivers/rtc/rtc-abx80x.c b/drivers/rtc/rtc-abx80x.c
index 0e4c9a0..ba0d619 100644
--- a/drivers/rtc/rtc-abx80x.c
+++ b/drivers/rtc/rtc-abx80x.c
@@ -58,6 +58,7 @@
 #define ABX8XX_OSC_OSEL		BIT(7)
 
 #define ABX8XX_REG_OSS		0x1d
+#define ABX8XX_OSS_OF		BIT(1)
 #define ABX8XX_OSS_OMODE	BIT(4)
 
 #define ABX8XX_REG_CFG_KEY	0x1f
@@ -138,7 +139,23 @@ static int abx80x_rtc_read_time(struct device *dev, struct rtc_time *tm)
 {
 	struct i2c_client *client = to_i2c_client(dev);
 	unsigned char buf[8];
-	int err;
+	int err, flags, rc_mode = 0;
+
+	/* Read the Oscillator Failure only in XT mode */
+	rc_mode = abx80x_is_rc_mode(client);
+	if (rc_mode < 0)
+		return rc_mode;
+
+	if (!rc_mode) {
+		flags = i2c_smbus_read_byte_data(client, ABX8XX_REG_OSS);
+		if (flags < 0)
+			return flags;
+
+		if (flags & ABX8XX_OSS_OF) {
+			dev_err(dev, "Oscillator failure, data is invalid.\n");
+			return -EINVAL;
+		}
+	}
 
 	err = i2c_smbus_read_i2c_block_data(client, ABX8XX_REG_HTH,
 					    sizeof(buf), buf);
@@ -166,7 +183,7 @@ static int abx80x_rtc_set_time(struct device *dev, struct rtc_time *tm)
 {
 	struct i2c_client *client = to_i2c_client(dev);
 	unsigned char buf[8];
-	int err;
+	int err, flags;
 
 	if (tm->tm_year < 100)
 		return -EINVAL;
@@ -187,6 +204,18 @@ static int abx80x_rtc_set_time(struct device *dev, struct rtc_time *tm)
 		return -EIO;
 	}
 
+	/* Clear the OF bit of Oscillator Status Register */
+	flags = i2c_smbus_read_byte_data(client, ABX8XX_REG_OSS);
+	if (flags < 0)
+		return flags;
+
+	err = i2c_smbus_write_byte_data(client, ABX8XX_REG_OSS,
+					flags & ~ABX8XX_OSS_OF);
+	if (err < 0) {
+		dev_err(&client->dev, "Unable to write oscillator status register\n");
+		return err;
+	}
+
 	return 0;
 }
 
-- 
2.7.0

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[PATCH 2/2] rtc: abx80x: handle the oscillator failure bit

[Mylene JOSSERAND]

Handle the Oscillator Failure ('OF') bit from Oscillator Status register
(0x1D). This bit is cleared on set_time function and is read each time the
date/time is read, but only in case of XT Oscillator selection.
In RC mode, this bit is always set.

Signed-off-by: Mylene JOSSERAND <mylene.josserand@free-electrons.com>
---
 drivers/rtc/rtc-abx80x.c | 33 +++++++++++++++++++++++++++++++--
 1 file changed, 31 insertions(+), 2 deletions(-)

diff --git a/drivers/rtc/rtc-abx80x.c b/drivers/rtc/rtc-abx80x.c
index 0e4c9a0..ba0d619 100644
--- a/drivers/rtc/rtc-abx80x.c
+++ b/drivers/rtc/rtc-abx80x.c
@@ -58,6 +58,7 @@
 #define ABX8XX_OSC_OSEL		BIT(7)
 
 #define ABX8XX_REG_OSS		0x1d
+#define ABX8XX_OSS_OF		BIT(1)
 #define ABX8XX_OSS_OMODE	BIT(4)
 
 #define ABX8XX_REG_CFG_KEY	0x1f
@@ -138,7 +139,23 @@ static int abx80x_rtc_read_time(struct device *dev, struct rtc_time *tm)
 {
 	struct i2c_client *client = to_i2c_client(dev);
 	unsigned char buf[8];
-	int err;
+	int err, flags, rc_mode = 0;
+
+	/* Read the Oscillator Failure only in XT mode */
+	rc_mode = abx80x_is_rc_mode(client);
+	if (rc_mode < 0)
+		return rc_mode;
+
+	if (!rc_mode) {
+		flags = i2c_smbus_read_byte_data(client, ABX8XX_REG_OSS);
+		if (flags < 0)
+			return flags;
+
+		if (flags & ABX8XX_OSS_OF) {
+			dev_err(dev, "Oscillator failure, data is invalid.\n");
+			return -EINVAL;
+		}
+	}
 
 	err = i2c_smbus_read_i2c_block_data(client, ABX8XX_REG_HTH,
 					    sizeof(buf), buf);
@@ -166,7 +183,7 @@ static int abx80x_rtc_set_time(struct device *dev, struct rtc_time *tm)
 {
 	struct i2c_client *client = to_i2c_client(dev);
 	unsigned char buf[8];
-	int err;
+	int err, flags;
 
 	if (tm->tm_year < 100)
 		return -EINVAL;
@@ -187,6 +204,18 @@ static int abx80x_rtc_set_time(struct device *dev, struct rtc_time *tm)
 		return -EIO;
 	}
 
+	/* Clear the OF bit of Oscillator Status Register */
+	flags = i2c_smbus_read_byte_data(client, ABX8XX_REG_OSS);
+	if (flags < 0)
+		return flags;
+
+	err = i2c_smbus_write_byte_data(client, ABX8XX_REG_OSS,
+					flags & ~ABX8XX_OSS_OF);
+	if (err < 0) {
+		dev_err(&client->dev, "Unable to write oscillator status register\n");
+		return err;
+	}
+
 	return 0;
 }
 
-- 
2.7.0

[rtc-linux] Re: [PATCH 0/2] rtc: abx80x: Handle autocalibration and oscillator failure

[Alexandre Belloni]

On 21/03/2016 at 18:06:08 +0100, Mylene JOSSERAND wrote :
> The current patches handle the autocalibration and the oscillator failure
> for ABX80X RTC.
> The autocalibration is handled using sysfs entries and the oscillator
> failure bit is handled only for the XT Oscillator.
> 
> Mylene JOSSERAND (2):
>   rtc: abx80x: handle autocalibration
>   rtc: abx80x: handle the oscillator failure bit
> 

Both applied, thanks.

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

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Re: [PATCH 0/2] rtc: abx80x: Handle autocalibration and oscillator failure

[Alexandre Belloni]

On 21/03/2016 at 18:06:08 +0100, Mylene JOSSERAND wrote :
> The current patches handle the autocalibration and the oscillator failure
> for ABX80X RTC.
> The autocalibration is handled using sysfs entries and the oscillator
> failure bit is handled only for the XT Oscillator.
> 
> Mylene JOSSERAND (2):
>   rtc: abx80x: handle autocalibration
>   rtc: abx80x: handle the oscillator failure bit
> 

Both applied, thanks.

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