From: Sean Anderson <sean.anderson@seco.com>
To: Alessandro Zummo <a.zummo@towertech.it>,
Alexandre Belloni <alexandre.belloni@bootlin.com>,
linux-rtc@vger.kernel.org
Cc: linux-kernel@vger.kernel.org
Subject: Re: [PATCH v3] rtc: abx80x: Don't warn about oscillator failure after PoR
Date: Thu, 25 Jan 2024 12:14:55 -0500 [thread overview]
Message-ID: <c7c90be3-8dcd-4737-9fce-01343da01855@seco.com> (raw)
In-Reply-To: <ff40a221-38b5-40d7-a0fc-cf617853a096@seco.com>
On 1/8/24 17:05, Sean Anderson wrote:
> 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@seco.com>
>>> ---
>>> 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?
Does anyone read this list? This patch has gone unreviewed since December of 2022!
--Sean
prev parent reply other threads:[~2024-01-25 17:15 UTC|newest]
Thread overview: 4+ messages / expand[flat|nested] mbox.gz Atom feed top
2023-10-19 16:39 [PATCH v3] rtc: abx80x: Don't warn about oscillator failure after PoR Sean Anderson
2023-12-11 16:03 ` Sean Anderson
2024-01-08 22:05 ` Sean Anderson
2024-01-25 17:14 ` Sean Anderson [this message]
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