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rtc: pcf8523: avoid reading BLF in pcf8523_rtc_read_time

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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: Alexandre Belloni <alexandre.belloni@bootlin.com>
Link: https://lore.kernel.org/r/20211015192400.818254-1-alexandre.belloni@bootlin.com
This commit is contained in:
Alexandre Belloni 2021-10-15 21:24:00 +02:00
parent 6084eac38e
commit 7d7234a4ff
1 changed files with 4 additions and 22 deletions
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26
drivers/rtc/rtc-pcf8523.c
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@ -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);