rtc: rv8803: return meaningful value for RTC_VL_READ

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.

Link: https://lore.kernel.org/r/20191214220259.621996-16-alexandre.belloni@bootlin.comSigned-off-by: Alexandre Belloni <alexandre.belloni@bootlin.com>

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");
+			vl |= RTC_VL_DATA_INVALID;
 
-		flags &= RV8803_FLAG_V1F | RV8803_FLAG_V2F;
-
-		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);