Commit 7d7234a4 authored by Alexandre Belloni's avatar Alexandre Belloni
Browse files

rtc: pcf8523: avoid reading BLF in pcf8523_rtc_read_time 



BLF, battery low doesn't mean the time is imprecise or invalid, it simply mean
the backup battery has to be replaced. This information can be read using the
VL_READ ioctl.

Signed-off-by: default avatarAlexandre Belloni <alexandre.belloni@bootlin.com>
Link: https://lore.kernel.org/r/20211015192400.818254-1-alexandre.belloni@bootlin.com
parent 6084eac3

drivers/rtc/rtc-pcf8523.c

+4 −22
Original line number Diff line number Diff line
@@ -24,6 +24,7 @@ 
#define PCF8523_CONTROL3_PM_DSM BIT(5) /* direct switching mode */

#define PCF8523_CONTROL3_PM_MASK 0xe0

#define PCF8523_CONTROL3_BLF BIT(2) /* battery low bit, read-only */

#define PCF8523_CONTROL3_BSF BIT(3)



#define PCF8523_REG_SECONDS  0x03

#define PCF8523_SECONDS_OS BIT(7)
@@ -94,18 +95,6 @@ static int pcf8523_write(struct i2c_client *client, u8 reg, u8 value) 
	return 0;

}



static int pcf8523_voltage_low(struct i2c_client *client)

{

	u8 value;

	int err;



	err = pcf8523_read(client, PCF8523_REG_CONTROL3, &value);

	if (err < 0)

		return err;



	return !!(value & PCF8523_CONTROL3_BLF);

}



static int pcf8523_load_capacitance(struct i2c_client *client)

{

	u32 load;
@@ -220,14 +209,6 @@ static int pcf8523_rtc_read_time(struct device *dev, struct rtc_time *tm) 
	struct i2c_msg msgs[2];

	int err;



	err = pcf8523_voltage_low(client);

	if (err < 0) {

		return err;

	} else if (err > 0) {

		dev_err(dev, "low voltage detected, time is unreliable\n");

		return -EINVAL;

	}



	msgs[0].addr = client->addr;

	msgs[0].flags = 0;

	msgs[0].len = 1;
@@ -412,10 +393,11 @@ static int pcf8523_rtc_ioctl(struct device *dev, unsigned int cmd, 


	switch (cmd) {

	case RTC_VL_READ:

		ret = pcf8523_voltage_low(client);

		ret = pcf8523_read(client, PCF8523_REG_CONTROL3, &value);

		if (ret < 0)

			return ret;

		if (ret)



		if (value & PCF8523_CONTROL3_BLF)

			flags |= RTC_VL_BACKUP_LOW;



		ret = pcf8523_read(client, PCF8523_REG_SECONDS, &value);