[PATCH 00/17] rtc: Unify RTC_VL_READ meaning

[PATCH 00/17] rtc: Unify RTC_VL_READ meaning

[Alexandre Belloni]

Hi,

This series unifies the meaning of RTC_VL_READ by redefining it as a
bitfield and defining the values of the various bits. This doesn't break
compatibility with userspaceas long as the return value was used as a
boolean, which should be the case.

The series also ensures RTC_VL_CLR doesn't clear the information when it
is about the data being invalid so the following rtc reads will properly
fail.

Alexandre Belloni (17):
  rtc: define RTC_VL_READ values
  rtc: Document RTC_VL_READ and RTC_VL_CLR ioctls
  rtc: abx80x: return meaningful value for RTC_VL_READ
  rtc: pcf2127: return meaningful value for RTC_VL_READ
  rtc: pcf8523: return meaningful value for RTC_VL_READ
  rtc: pcf8563: remove RTC_VL_CLR handling
  rtc: pcf8563: remove conditional compilation
  rtc: pcf8563: stop caching voltage_low
  rtc: pcf8563: return meaningful value for RTC_VL_READ
  rtc: pcf85063: remove RTC_VL_CLR handling
  rtc: pcf85063: return meaningful value for RTC_VL_READ
  rtc: rv3028: remove RTC_VL_CLR handling
  rtc: rv3028: return meaningful value for RTC_VL_READ
  rtc: rv8803: avoid clearing RV8803_FLAG_V2F in RTC_VL_CLR
  rtc: rv8803: return meaningful value for RTC_VL_READ
  rtc: rx8010: remove RTC_VL_CLR handling
  rtc: rx8010: return meaningful value for RTC_VL_READ

 Documentation/ABI/testing/rtc-cdev |  8 +++++++
 drivers/rtc/rtc-abx80x.c           |  7 ++----
 drivers/rtc/rtc-pcf2127.c          |  6 ++---
 drivers/rtc/rtc-pcf85063.c         | 16 ++-----------
 drivers/rtc/rtc-pcf8523.c          |  6 ++---
 drivers/rtc/rtc-pcf8563.c          | 36 ++++++------------------------
 drivers/rtc/rtc-rv3028.c           | 17 ++------------
 drivers/rtc/rtc-rv8803.c           | 16 ++++++-------
 drivers/rtc/rtc-rx8010.c           | 23 +++----------------
 include/uapi/linux/rtc.h           |  7 +++++-
 10 files changed, 42 insertions(+), 100 deletions(-)

-- 
2.23.0

[PATCH 01/17] rtc: define RTC_VL_READ values

[Alexandre Belloni]

Currently, the meaning of the value returned by RTC_VL_READ is undocumented
and left to the driver implementation. In order to get more meaningful
values, define a set of values to use as to make clear to userspace what is
the status of the various voltages feeding the RTC.

Signed-off-by: Alexandre Belloni <alexandre.belloni@bootlin.com>
---
 include/uapi/linux/rtc.h | 7 ++++++-
 1 file changed, 6 insertions(+), 1 deletion(-)

diff --git a/include/uapi/linux/rtc.h b/include/uapi/linux/rtc.h
index 2ad1788968d0..095af360326a 100644
--- a/include/uapi/linux/rtc.h
+++ b/include/uapi/linux/rtc.h
@@ -92,7 +92,12 @@ struct rtc_pll_info {
 #define RTC_PLL_GET	_IOR('p', 0x11, struct rtc_pll_info)  /* Get PLL correction */
 #define RTC_PLL_SET	_IOW('p', 0x12, struct rtc_pll_info)  /* Set PLL correction */
 
-#define RTC_VL_READ	_IOR('p', 0x13, int)	/* Voltage low detector */
+#define RTC_VL_DATA_INVALID	BIT(0) /* Voltage too low, RTC data is invalid */
+#define RTC_VL_BACKUP_LOW	BIT(1) /* Backup voltage is low */
+#define RTC_VL_BACKUP_EMPTY	BIT(2) /* Backup empty or not present */
+#define RTC_VL_ACCURACY_LOW	BIT(3) /* Voltage is low, RTC accuracy is reduced */
+
+#define RTC_VL_READ	_IOR('p', 0x13, unsigned int)	/* Voltage low detection */
 #define RTC_VL_CLR	_IO('p', 0x14)		/* Clear voltage low information */
 
 /* interrupt flags */
-- 
2.23.0

[PATCH 02/17] rtc: Document RTC_VL_READ and RTC_VL_CLR ioctls

[Alexandre Belloni]

RTC_VL_READ and RTC_VL_CLR have been introduced in 2012 with commit
0f20b767e20a ("drivers/rtc/rtc-pcf8563.c: add RTC_VL_READ/RTC_VL_CLR ioctl
feature")

Document them now that they have been unified.

Signed-off-by: Alexandre Belloni <alexandre.belloni@bootlin.com>
---
 Documentation/ABI/testing/rtc-cdev | 8 ++++++++
 1 file changed, 8 insertions(+)

diff --git a/Documentation/ABI/testing/rtc-cdev b/Documentation/ABI/testing/rtc-cdev
index 97447283f13b..25910c3c3d7e 100644
--- a/Documentation/ABI/testing/rtc-cdev
+++ b/Documentation/ABI/testing/rtc-cdev
@@ -33,6 +33,14 @@ Description:
 		  Requires a separate RTC_PIE_ON call to enable the periodic
 		  interrupts.
 
+		* RTC_VL_READ: Read the voltage inputs status of the RTC when
+		  supported. The value is a bit field of RTC_VL_*, giving the
+		  status of the main and backup voltages.
+
+		* RTC_VL_CLEAR: Clear the voltage status of the RTC. Some RTCs
+		  need user interaction when the backup power provider is
+		  replaced or charged to be able to clear the status.
+
 		The ioctl() calls supported by the older /dev/rtc interface are
 		also supported by the newer RTC class framework. However,
 		because the chips and systems are not standardized, some PC/AT
-- 
2.23.0

[PATCH 03/17] rtc: abx80x: return meaningful value for RTC_VL_READ

[Alexandre Belloni]

ABX8XX_STATUS_BLF indicates the battery is low and needs to be replaced
soon.

Signed-off-by: Alexandre Belloni <alexandre.belloni@bootlin.com>
---
 drivers/rtc/rtc-abx80x.c | 7 ++-----
 1 file changed, 2 insertions(+), 5 deletions(-)

diff --git a/drivers/rtc/rtc-abx80x.c b/drivers/rtc/rtc-abx80x.c
index 73830670a41f..3521d8e8dc38 100644
--- a/drivers/rtc/rtc-abx80x.c
+++ b/drivers/rtc/rtc-abx80x.c
@@ -523,12 +523,9 @@ static int abx80x_ioctl(struct device *dev, unsigned int cmd, unsigned long arg)
 		if (status < 0)
 			return status;
 
-		tmp = !!(status & ABX8XX_STATUS_BLF);
+		tmp = status & ABX8XX_STATUS_BLF ? RTC_VL_BACKUP_LOW : 0;
 
-		if (copy_to_user((void __user *)arg, &tmp, sizeof(int)))
-			return -EFAULT;
-
-		return 0;
+		return put_user(tmp, (unsigned int __user *)arg);
 
 	case RTC_VL_CLR:
 		status = i2c_smbus_read_byte_data(client, ABX8XX_REG_STATUS);
-- 
2.23.0

[PATCH 04/17] rtc: pcf2127: return meaningful value for RTC_VL_READ

[Alexandre Belloni]

PCF2127_BIT_CTRL3_BLF indicates the battery is low and needs to be replaced
soon.

Signed-off-by: Alexandre Belloni <alexandre.belloni@bootlin.com>
---
 drivers/rtc/rtc-pcf2127.c | 6 ++----
 1 file changed, 2 insertions(+), 4 deletions(-)

diff --git a/drivers/rtc/rtc-pcf2127.c b/drivers/rtc/rtc-pcf2127.c
index 5d8ea9ffd05b..5ac996578523 100644
--- a/drivers/rtc/rtc-pcf2127.c
+++ b/drivers/rtc/rtc-pcf2127.c
@@ -197,11 +197,9 @@ static int pcf2127_rtc_ioctl(struct device *dev,
 		if (ret)
 			return ret;
 
-		touser = touser & PCF2127_BIT_CTRL3_BLF ? 1 : 0;
+		touser = touser & PCF2127_BIT_CTRL3_BLF ? RTC_VL_BACKUP_LOW : 0;
 
-		if (copy_to_user((void __user *)arg, &touser, sizeof(int)))
-			return -EFAULT;
-		return 0;
+		return put_user(touser, (unsigned int __user *)arg);
 	default:
 		return -ENOIOCTLCMD;
 	}
-- 
2.23.0

[PATCH 05/17] rtc: pcf8523: return meaningful value for RTC_VL_READ

[Alexandre Belloni]

REG_CONTROL3_BLF indicates the battery is low and needs to be replaced
soon.

Signed-off-by: Alexandre Belloni <alexandre.belloni@bootlin.com>
---
 drivers/rtc/rtc-pcf8523.c | 6 +++---
 1 file changed, 3 insertions(+), 3 deletions(-)

diff --git a/drivers/rtc/rtc-pcf8523.c b/drivers/rtc/rtc-pcf8523.c
index b24c908f5f06..47e0f411dd5c 100644
--- a/drivers/rtc/rtc-pcf8523.c
+++ b/drivers/rtc/rtc-pcf8523.c
@@ -282,11 +282,11 @@ static int pcf8523_rtc_ioctl(struct device *dev, unsigned int cmd,
 		ret = pcf8523_voltage_low(client);
 		if (ret < 0)
 			return ret;
+		if (ret)
+			ret = RTC_VL_BACKUP_LOW;
 
-		if (copy_to_user((void __user *)arg, &ret, sizeof(int)))
-			return -EFAULT;
+		return put_user(ret, (unsigned int __user *)arg);
 
-		return 0;
 	default:
 		return -ENOIOCTLCMD;
 	}
-- 
2.23.0

[PATCH 06/17] rtc: pcf8563: remove RTC_VL_CLR handling

[Alexandre Belloni]

Remove RTC_VL_CLR handling because it is a disservice to userspace as it
removes the important information that the RTC data is invalid. This may
lead userspace to set an invalid system time later on.

Signed-off-by: Alexandre Belloni <alexandre.belloni@bootlin.com>
---
 drivers/rtc/rtc-pcf8563.c | 15 ---------------
 1 file changed, 15 deletions(-)

diff --git a/drivers/rtc/rtc-pcf8563.c b/drivers/rtc/rtc-pcf8563.c
index 3c322f3079b0..c701eef82349 100644
--- a/drivers/rtc/rtc-pcf8563.c
+++ b/drivers/rtc/rtc-pcf8563.c
@@ -291,21 +291,6 @@ static int pcf8563_rtc_ioctl(struct device *dev, unsigned int cmd, unsigned long
 					sizeof(int)))
 			return -EFAULT;
 		return 0;
-	case RTC_VL_CLR:
-		/*
-		 * Clear the VL bit in the seconds register in case
-		 * the time has not been set already (which would
-		 * have cleared it). This does not really matter
-		 * because of the cached voltage_low value but do it
-		 * anyway for consistency.
-		 */
-		if (pcf8563_rtc_read_time(dev, &tm))
-			pcf8563_rtc_set_time(dev, &tm);
-
-		/* Clear the cached value. */
-		pcf8563->voltage_low = 0;
-
-		return 0;
 	default:
 		return -ENOIOCTLCMD;
 	}
-- 
2.23.0

[PATCH 07/17] rtc: pcf8563: remove conditional compilation

[Alexandre Belloni]

Always compile pcf8563_rtc_ioctl as we are sure that CONFIG_RTC_INTF_DEV is
selected on actual kernel configurations.

Signed-off-by: Alexandre Belloni <alexandre.belloni@bootlin.com>
---
 drivers/rtc/rtc-pcf8563.c | 5 -----
 1 file changed, 5 deletions(-)

diff --git a/drivers/rtc/rtc-pcf8563.c b/drivers/rtc/rtc-pcf8563.c
index c701eef82349..026192fc0c2a 100644
--- a/drivers/rtc/rtc-pcf8563.c
+++ b/drivers/rtc/rtc-pcf8563.c
@@ -276,11 +276,9 @@ static int pcf8563_rtc_set_time(struct device *dev, struct rtc_time *tm)
 				9 - PCF8563_REG_SC, buf + PCF8563_REG_SC);
 }
 
-#ifdef CONFIG_RTC_INTF_DEV
 static int pcf8563_rtc_ioctl(struct device *dev, unsigned int cmd, unsigned long arg)
 {
 	struct pcf8563 *pcf8563 = i2c_get_clientdata(to_i2c_client(dev));
-	struct rtc_time tm;
 
 	switch (cmd) {
 	case RTC_VL_READ:
@@ -295,9 +293,6 @@ static int pcf8563_rtc_ioctl(struct device *dev, unsigned int cmd, unsigned long
 		return -ENOIOCTLCMD;
 	}
 }
-#else
-#define pcf8563_rtc_ioctl NULL
-#endif
 
 static int pcf8563_rtc_read_alarm(struct device *dev, struct rtc_wkalrm *tm)
 {
-- 
2.23.0

[PATCH 08/17] rtc: pcf8563: stop caching voltage_low

[Alexandre Belloni]

voltage_low is only updated when reading the time, this means that using
RTC_VL_READ will miss the VL flag if the time has not been read before
using the ioctl. Always read the status from the hardware.

Signed-off-by: Alexandre Belloni <alexandre.belloni@bootlin.com>
---
 drivers/rtc/rtc-pcf8563.c | 16 +++++++++-------
 1 file changed, 9 insertions(+), 7 deletions(-)

diff --git a/drivers/rtc/rtc-pcf8563.c b/drivers/rtc/rtc-pcf8563.c
index 026192fc0c2a..7fc43950cf6c 100644
--- a/drivers/rtc/rtc-pcf8563.c
+++ b/drivers/rtc/rtc-pcf8563.c
@@ -76,7 +76,6 @@ struct pcf8563 {
 	 * 1970...2069.
 	 */
 	int c_polarity;	/* 0: MO_C=1 means 19xx, otherwise MO_C=1 means 20xx */
-	int voltage_low; /* incicates if a low_voltage was detected */
 
 	struct i2c_client *client;
 #ifdef CONFIG_COMMON_CLK
@@ -208,7 +207,6 @@ static int pcf8563_rtc_read_time(struct device *dev, struct rtc_time *tm)
 		return err;
 
 	if (buf[PCF8563_REG_SC] & PCF8563_SC_LV) {
-		pcf8563->voltage_low = 1;
 		dev_err(&client->dev,
 			"low voltage detected, date/time is not reliable.\n");
 		return -EINVAL;
@@ -278,15 +276,19 @@ static int pcf8563_rtc_set_time(struct device *dev, struct rtc_time *tm)
 
 static int pcf8563_rtc_ioctl(struct device *dev, unsigned int cmd, unsigned long arg)
 {
-	struct pcf8563 *pcf8563 = i2c_get_clientdata(to_i2c_client(dev));
+	struct i2c_client *client = to_i2c_client(dev);
+	int vl, ret;
 
 	switch (cmd) {
 	case RTC_VL_READ:
-		if (pcf8563->voltage_low)
-			dev_info(dev, "low voltage detected, date/time is not reliable.\n");
 
-		if (copy_to_user((void __user *)arg, &pcf8563->voltage_low,
-					sizeof(int)))
+		ret = i2c_smbus_read_byte_data(client, PCF8563_REG_SC);
+		if (ret < 0)
+			return ret;
+
+		vl = ret & PCF8563_SC_LV ? 1 : 0;
+
+		if (copy_to_user((void __user *)arg, &vl, sizeof(int)))
 			return -EFAULT;
 		return 0;
 	default:
-- 
2.23.0

[PATCH 09/17] rtc: pcf8563: return meaningful value for RTC_VL_READ

[Alexandre Belloni]

PCF8563_SC_LV means the voltage dropped too low and data has been lost.

Signed-off-by: Alexandre Belloni <alexandre.belloni@bootlin.com>
---
 drivers/rtc/rtc-pcf8563.c | 10 +++-------
 1 file changed, 3 insertions(+), 7 deletions(-)

diff --git a/drivers/rtc/rtc-pcf8563.c b/drivers/rtc/rtc-pcf8563.c
index 7fc43950cf6c..b282c6b07969 100644
--- a/drivers/rtc/rtc-pcf8563.c
+++ b/drivers/rtc/rtc-pcf8563.c
@@ -277,20 +277,16 @@ static int pcf8563_rtc_set_time(struct device *dev, struct rtc_time *tm)
 static int pcf8563_rtc_ioctl(struct device *dev, unsigned int cmd, unsigned long arg)
 {
 	struct i2c_client *client = to_i2c_client(dev);
-	int vl, ret;
+	int ret;
 
 	switch (cmd) {
 	case RTC_VL_READ:
-
 		ret = i2c_smbus_read_byte_data(client, PCF8563_REG_SC);
 		if (ret < 0)
 			return ret;
 
-		vl = ret & PCF8563_SC_LV ? 1 : 0;
-
-		if (copy_to_user((void __user *)arg, &vl, sizeof(int)))
-			return -EFAULT;
-		return 0;
+		return put_user(ret & PCF8563_SC_LV ? RTC_VL_DATA_INVALID : 0,
+				(unsigned int __user *)arg);
 	default:
 		return -ENOIOCTLCMD;
 	}
-- 
2.23.0

[PATCH 10/17] rtc: pcf85063: remove RTC_VL_CLR handling

[Alexandre Belloni]

Remove RTC_VL_CLR handling because it is a disservice to userspace as it
removes the important information that the RTC data is invalid. This may
lead userspace to set an invalid system time later on.

Signed-off-by: Alexandre Belloni <alexandre.belloni@bootlin.com>
---
 drivers/rtc/rtc-pcf85063.c | 6 ------
 1 file changed, 6 deletions(-)

diff --git a/drivers/rtc/rtc-pcf85063.c b/drivers/rtc/rtc-pcf85063.c
index 1afa6d9fa9fb..2ddd95420a8c 100644
--- a/drivers/rtc/rtc-pcf85063.c
+++ b/drivers/rtc/rtc-pcf85063.c
@@ -299,12 +299,6 @@ static int pcf85063_ioctl(struct device *dev, unsigned int cmd,
 
 		return 0;
 
-	case RTC_VL_CLR:
-		ret = regmap_update_bits(pcf85063->regmap, PCF85063_REG_SC,
-					 PCF85063_REG_SC_OS, 0);
-
-		return ret;
-
 	default:
 		return -ENOIOCTLCMD;
 	}
-- 
2.23.0

[PATCH 11/17] rtc: pcf85063: return meaningful value for RTC_VL_READ

[Alexandre Belloni]

PCF85063_REG_SC_OS means the voltage dropped too low and data has been
lost.

Signed-off-by: Alexandre Belloni <alexandre.belloni@bootlin.com>
---
 drivers/rtc/rtc-pcf85063.c | 10 ++--------
 1 file changed, 2 insertions(+), 8 deletions(-)

diff --git a/drivers/rtc/rtc-pcf85063.c b/drivers/rtc/rtc-pcf85063.c
index 2ddd95420a8c..1db17ba1fc64 100644
--- a/drivers/rtc/rtc-pcf85063.c
+++ b/drivers/rtc/rtc-pcf85063.c
@@ -289,15 +289,9 @@ static int pcf85063_ioctl(struct device *dev, unsigned int cmd,
 		if (ret < 0)
 			return ret;
 
-		if (status & PCF85063_REG_SC_OS)
-			dev_warn(&pcf85063->rtc->dev, "Voltage low, data loss detected.\n");
+		status = status & PCF85063_REG_SC_OS ? RTC_VL_DATA_INVALID : 0;
 
-		status &= PCF85063_REG_SC_OS;
-
-		if (copy_to_user((void __user *)arg, &status, sizeof(int)))
-			return -EFAULT;
-
-		return 0;
+		return put_user(status, (unsigned int __user *)arg);
 
 	default:
 		return -ENOIOCTLCMD;
-- 
2.23.0

[PATCH 12/17] rtc: rv3028: remove RTC_VL_CLR handling

[Alexandre Belloni]

Remove RTC_VL_CLR handling because it is a disservice to userspace as it
removes the important information that the RTC data is invalid. This may
lead userspace to set an invalid system time later on.

Signed-off-by: Alexandre Belloni <alexandre.belloni@bootlin.com>
---
 drivers/rtc/rtc-rv3028.c | 6 ------
 1 file changed, 6 deletions(-)

diff --git a/drivers/rtc/rtc-rv3028.c b/drivers/rtc/rtc-rv3028.c
index 6b7b3a69601a..d1a2c22861f2 100644
--- a/drivers/rtc/rtc-rv3028.c
+++ b/drivers/rtc/rtc-rv3028.c
@@ -438,12 +438,6 @@ static int rv3028_ioctl(struct device *dev, unsigned int cmd, unsigned long arg)
 
 		return 0;
 
-	case RTC_VL_CLR:
-		ret = regmap_update_bits(rv3028->regmap, RV3028_STATUS,
-					 RV3028_STATUS_PORF, 0);
-
-		return ret;
-
 	default:
 		return -ENOIOCTLCMD;
 	}
-- 
2.23.0

[PATCH 13/17] rtc: rv3028: return meaningful value for RTC_VL_READ

[Alexandre Belloni]

RV3028_STATUS_PORF means the voltage dropped too low and data has been
lost.

Signed-off-by: Alexandre Belloni <alexandre.belloni@bootlin.com>
---
 drivers/rtc/rtc-rv3028.c | 11 ++---------
 1 file changed, 2 insertions(+), 9 deletions(-)

diff --git a/drivers/rtc/rtc-rv3028.c b/drivers/rtc/rtc-rv3028.c
index d1a2c22861f2..a0ddc86c975a 100644
--- a/drivers/rtc/rtc-rv3028.c
+++ b/drivers/rtc/rtc-rv3028.c
@@ -428,15 +428,8 @@ static int rv3028_ioctl(struct device *dev, unsigned int cmd, unsigned long arg)
 		if (ret < 0)
 			return ret;
 
-		if (status & RV3028_STATUS_PORF)
-			dev_warn(&rv3028->rtc->dev, "Voltage low, data loss detected.\n");
-
-		status &= RV3028_STATUS_PORF;
-
-		if (copy_to_user((void __user *)arg, &status, sizeof(int)))
-			return -EFAULT;
-
-		return 0;
+		status = status & RV3028_STATUS_PORF ? RTC_VL_DATA_INVALID : 0;
+		return put_user(status, (unsigned int __user *)arg);
 
 	default:
 		return -ENOIOCTLCMD;
-- 
2.23.0

[PATCH 14/17] rtc: rv8803: avoid clearing RV8803_FLAG_V2F in RTC_VL_CLR

[Alexandre Belloni]

Stop clearing RV8803_FLAG_V2F in RTC_VL_CLR because it is a disservice to
userspace as it removes the important information that the RTC data is
invalid. This may lead userspace to set an invalid system time later on.

Signed-off-by: Alexandre Belloni <alexandre.belloni@bootlin.com>
---
 drivers/rtc/rtc-rv8803.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/drivers/rtc/rtc-rv8803.c b/drivers/rtc/rtc-rv8803.c
index 4960f0a2b249..ed92116bdfa0 100644
--- a/drivers/rtc/rtc-rv8803.c
+++ b/drivers/rtc/rtc-rv8803.c
@@ -440,7 +440,7 @@ static int rv8803_ioctl(struct device *dev, unsigned int cmd, unsigned long arg)
 			return flags;
 		}
 
-		flags &= ~(RV8803_FLAG_V1F | RV8803_FLAG_V2F);
+		flags &= ~RV8803_FLAG_V1F;
 		ret = rv8803_write_reg(client, RV8803_FLAG, flags);
 		mutex_unlock(&rv8803->flags_lock);
 		if (ret)
-- 
2.23.0

[PATCH 15/17] rtc: rv8803: return meaningful value for RTC_VL_READ

[Alexandre Belloni]

RV8803_FLAG_V1F means the voltage is too low to keep the temperature
compensation running and the accuracy of the RTC is affected.

RV8803_FLAG_V2F means the voltage dropped so low that data is now invalid.

Signed-off-by: Alexandre Belloni <alexandre.belloni@bootlin.com>
---
 drivers/rtc/rtc-rv8803.c | 14 ++++++--------
 1 file changed, 6 insertions(+), 8 deletions(-)

diff --git a/drivers/rtc/rtc-rv8803.c b/drivers/rtc/rtc-rv8803.c
index ed92116bdfa0..93c3a6b627bd 100644
--- a/drivers/rtc/rtc-rv8803.c
+++ b/drivers/rtc/rtc-rv8803.c
@@ -411,6 +411,7 @@ static int rv8803_ioctl(struct device *dev, unsigned int cmd, unsigned long arg)
 {
 	struct i2c_client *client = to_i2c_client(dev);
 	struct rv8803_data *rv8803 = dev_get_drvdata(dev);
+	unsigned int vl = 0;
 	int flags, ret = 0;
 
 	switch (cmd) {
@@ -419,18 +420,15 @@ static int rv8803_ioctl(struct device *dev, unsigned int cmd, unsigned long arg)
 		if (flags < 0)
 			return flags;
 
-		if (flags & RV8803_FLAG_V1F)
+		if (flags & RV8803_FLAG_V1F) {
 			dev_warn(&client->dev, "Voltage low, temperature compensation stopped.\n");
+			vl = RTC_VL_ACCURACY_LOW;
+		}
 
 		if (flags & RV8803_FLAG_V2F)
-			dev_warn(&client->dev, "Voltage low, data loss detected.\n");
-
-		flags &= RV8803_FLAG_V1F | RV8803_FLAG_V2F;
+			vl |= RTC_VL_DATA_INVALID;
 
-		if (copy_to_user((void __user *)arg, &flags, sizeof(int)))
-			return -EFAULT;
-
-		return 0;
+		return put_user(vl, (unsigned int __user *)arg);
 
 	case RTC_VL_CLR:
 		mutex_lock(&rv8803->flags_lock);
-- 
2.23.0

[PATCH 16/17] rtc: rx8010: remove RTC_VL_CLR handling

[Alexandre Belloni]

Remove RTC_VL_CLR handling because it is a disservice to userspace as it
removes the important information that the RTC data is invalid. This may
lead userspace to set an invalid system time later on.

Signed-off-by: Alexandre Belloni <alexandre.belloni@bootlin.com>
---
 drivers/rtc/rtc-rx8010.c | 16 +---------------
 1 file changed, 1 insertion(+), 15 deletions(-)

diff --git a/drivers/rtc/rtc-rx8010.c b/drivers/rtc/rtc-rx8010.c
index 8102469e27c0..9b106a26c64b 100644
--- a/drivers/rtc/rtc-rx8010.c
+++ b/drivers/rtc/rtc-rx8010.c
@@ -389,9 +389,8 @@ static int rx8010_alarm_irq_enable(struct device *dev,
 
 static int rx8010_ioctl(struct device *dev, unsigned int cmd, unsigned long arg)
 {
-	struct i2c_client *client = to_i2c_client(dev);
 	struct rx8010_data *rx8010 = dev_get_drvdata(dev);
-	int ret, tmp;
+	int tmp;
 	int flagreg;
 
 	switch (cmd) {
@@ -406,19 +405,6 @@ static int rx8010_ioctl(struct device *dev, unsigned int cmd, unsigned long arg)
 
 		return 0;
 
-	case RTC_VL_CLR:
-		flagreg = i2c_smbus_read_byte_data(rx8010->client, RX8010_FLAG);
-		if (flagreg < 0) {
-			return flagreg;
-		}
-
-		flagreg &= ~RX8010_FLAG_VLF;
-		ret = i2c_smbus_write_byte_data(client, RX8010_FLAG, flagreg);
-		if (ret < 0)
-			return ret;
-
-		return 0;
-
 	default:
 		return -ENOIOCTLCMD;
 	}
-- 
2.23.0

[PATCH 17/17] rtc: rx8010: return meaningful value for RTC_VL_READ

[Alexandre Belloni]

RX8010_FLAG_VLF means the voltage dropped too low and data has been lost.

Signed-off-by: Alexandre Belloni <alexandre.belloni@bootlin.com>
---
 drivers/rtc/rtc-rx8010.c | 7 ++-----
 1 file changed, 2 insertions(+), 5 deletions(-)

diff --git a/drivers/rtc/rtc-rx8010.c b/drivers/rtc/rtc-rx8010.c
index 9b106a26c64b..4021844bf2fa 100644
--- a/drivers/rtc/rtc-rx8010.c
+++ b/drivers/rtc/rtc-rx8010.c
@@ -399,11 +399,8 @@ static int rx8010_ioctl(struct device *dev, unsigned int cmd, unsigned long arg)
 		if (flagreg < 0)
 			return flagreg;
 
-		tmp = !!(flagreg & RX8010_FLAG_VLF);
-		if (copy_to_user((void __user *)arg, &tmp, sizeof(int)))
-			return -EFAULT;
-
-		return 0;
+		tmp = flagreg & RX8010_FLAG_VLF ? RTC_VL_DATA_INVALID : 0;
+		return put_user(tmp, (unsigned int __user *)arg);
 
 	default:
 		return -ENOIOCTLCMD;
-- 
2.23.0