Commit 935272aa authored by Alexandre Belloni's avatar Alexandre Belloni
Browse files

rtc: pcf8563: stop caching voltage_low 

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.

Link: https://lore.kernel.org/r/20191214220259.621996-9-alexandre.belloni@bootlin.com


Signed-off-by: default avatarAlexandre Belloni <alexandre.belloni@bootlin.com>
parent 75d26f5c

drivers/rtc/rtc-pcf8563.c

+9 −7
Original line number Diff line number Diff line
@@ -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: