diff options
| -rw-r--r-- | drivers/rtc/rtc-pcf8523.c | 32 |
1 files changed, 24 insertions, 8 deletions
diff --git a/drivers/rtc/rtc-pcf8523.c b/drivers/rtc/rtc-pcf8523.c index 453615f8ac9a..3fcd2cbafc84 100644 --- a/drivers/rtc/rtc-pcf8523.c +++ b/drivers/rtc/rtc-pcf8523.c @@ -85,6 +85,18 @@ 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, REG_CONTROL3, &value); + if (err < 0) + return err; + + return !!(value & REG_CONTROL3_BLF); +} + static int pcf8523_select_capacitance(struct i2c_client *client, bool high) { u8 value; @@ -167,6 +179,14 @@ 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; @@ -251,17 +271,13 @@ static int pcf8523_rtc_ioctl(struct device *dev, unsigned int cmd, unsigned long arg) { struct i2c_client *client = to_i2c_client(dev); - u8 value; - int ret = 0, err; + int ret; switch (cmd) { case RTC_VL_READ: - err = pcf8523_read(client, REG_CONTROL3, &value); - if (err < 0) - return err; - - if (value & REG_CONTROL3_BLF) - ret = 1; + ret = pcf8523_voltage_low(client); + if (ret < 0) + return ret; if (copy_to_user((void __user *)arg, &ret, sizeof(int))) return -EFAULT; |