On 12/11/23 11:03, Sean Anderson wrote:
> 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?
ping again?
