On 10/19/23 12:39, Sean Anderson wrote: > According to the datasheet, the "oscillator failure" bit is set > >> ...on a power on reset, when both the system and battery voltages have >> dropped below acceptable levels. It is also set if an Oscillator Failure >> occurs.... > > From testing, this bit is also set if a software reset is initiated. > > This bit has a confusing name; it really tells us whether the time data > is valid. We clear it when writing the time. If it is still set, that > means there is a persistent issue (such as an oscillator failure), > instead of a transient one (such as power loss). > > Because there are several other reasons which might cause this bit > to be set (including booting for the first time or a battery failure), > do not warn about oscillator failures willy-nilly. This may cause system > integrators to waste time looking into the wrong line of investigation. > > We continue printing a message about invalid time data or an oscillator > failure. There is no voltimeter in this RTC, so this is the best > indication that the battery is dead (or dying) and reeds replacement. > > Signed-off-by: Sean Anderson <sean.anderson@xxxxxxxx> > --- > Note that the following drivers all warn when they detect a problem with > the oscillator: > > drivers/rtc/rtc-ds1672.c > drivers/rtc/rtc-pcf*.c > drivers/rtc/rtc-rs5c*.c > drivers/rtc/rtc-sc27xx.c > > So warning about such an error has good precedent. > > Changes in v3: > - Use info since this is a good indication of a battery failure > > Changes in v2: > - Use debug instead of info in the typical case (no battery) > > drivers/rtc/rtc-abx80x.c | 17 ++++++++++++++++- > 1 file changed, 16 insertions(+), 1 deletion(-) > > diff --git a/drivers/rtc/rtc-abx80x.c b/drivers/rtc/rtc-abx80x.c > index fde2b8054c2e..f463a58a240b 100644 > --- a/drivers/rtc/rtc-abx80x.c > +++ b/drivers/rtc/rtc-abx80x.c > @@ -127,6 +127,7 @@ struct abx80x_priv { > struct rtc_device *rtc; > struct i2c_client *client; > struct watchdog_device wdog; > + bool wrote_time; > }; > > static int abx80x_write_config_key(struct i2c_client *client, u8 key) > @@ -179,6 +180,7 @@ static int abx80x_enable_trickle_charger(struct i2c_client *client, > static int abx80x_rtc_read_time(struct device *dev, struct rtc_time *tm) > { > struct i2c_client *client = to_i2c_client(dev); > + struct abx80x_priv *priv = i2c_get_clientdata(client); > unsigned char buf[8]; > int err, flags, rc_mode = 0; > > @@ -193,7 +195,18 @@ static int abx80x_rtc_read_time(struct device *dev, struct rtc_time *tm) > return flags; > > if (flags & ABX8XX_OSS_OF) { > - dev_err(dev, "Oscillator failure, data is invalid.\n"); > + /* > + * The OF bit can be set either because of a reset > + * (PoR/Software reset) or because of an oscillator > + * failure. Effectively, it indicates that the stored > + * time is invalid. When we write the time, we clear > + * this bit. If it stays set, then this indicates an > + * oscillator failure. > + */ > + if (priv->wrote_time) > + dev_err(dev, "Oscillator failure\n"); > + else > + dev_info(dev, "Time data invalid\n"); > return -EINVAL; > } > } > @@ -219,6 +232,7 @@ static int abx80x_rtc_read_time(struct device *dev, struct rtc_time *tm) > static int abx80x_rtc_set_time(struct device *dev, struct rtc_time *tm) > { > struct i2c_client *client = to_i2c_client(dev); > + struct abx80x_priv *priv = i2c_get_clientdata(client); > unsigned char buf[8]; > int err, flags; > > @@ -252,6 +266,7 @@ static int abx80x_rtc_set_time(struct device *dev, struct rtc_time *tm) > dev_err(&client->dev, "Unable to write oscillator status register\n"); > return err; > } > + priv->wrote_time = true; > > return 0; > } ping?