diff options
Diffstat (limited to 'drivers/rtc/rtc-pcf8523.c')
| -rw-r--r-- | drivers/rtc/rtc-pcf8523.c | 30 |
1 files changed, 29 insertions, 1 deletions
diff --git a/drivers/rtc/rtc-pcf8523.c b/drivers/rtc/rtc-pcf8523.c index 2c63c0ffd05a..0125000fa722 100644 --- a/drivers/rtc/rtc-pcf8523.c +++ b/drivers/rtc/rtc-pcf8523.c @@ -100,6 +100,7 @@ static int pcf8523_rtc_read_time(struct device *dev, struct rtc_time *tm) { struct pcf8523 *pcf8523 = dev_get_drvdata(dev); u8 regs[10]; + u32 value; int err; err = regmap_bulk_read(pcf8523->regmap, PCF8523_REG_CONTROL1, regs, @@ -107,9 +108,36 @@ static int pcf8523_rtc_read_time(struct device *dev, struct rtc_time *tm) if (err < 0) return err; - if ((regs[0] & PCF8523_CONTROL1_STOP) || (regs[3] & PCF8523_SECONDS_OS)) + if (regs[PCF8523_REG_CONTROL1] & PCF8523_CONTROL1_STOP) return -EINVAL; + if (regs[PCF8523_REG_SECONDS] & PCF8523_SECONDS_OS) { + /* + * If the oscillator was stopped, try to clear the flag. Upon + * power-up the flag is always set, but if we cannot clear it + * the oscillator isn't running properly for some reason. The + * sensible thing therefore is to return an error, signalling + * that the clock cannot be assumed to be correct. + */ + + regs[PCF8523_REG_SECONDS] &= ~PCF8523_SECONDS_OS; + + err = regmap_write(pcf8523->regmap, PCF8523_REG_SECONDS, + regs[PCF8523_REG_SECONDS]); + if (err < 0) + return err; + + err = regmap_read(pcf8523->regmap, PCF8523_REG_SECONDS, + &value); + if (err < 0) + return err; + + if (value & PCF8523_SECONDS_OS) + return -EAGAIN; + + regs[PCF8523_REG_SECONDS] = value; + } + tm->tm_sec = bcd2bin(regs[3] & 0x7f); tm->tm_min = bcd2bin(regs[4] & 0x7f); tm->tm_hour = bcd2bin(regs[5] & 0x3f); |