Messages in this thread | | | Date | Wed, 6 Feb 2019 10:58:10 +0100 | From | Alexandre Belloni <> | Subject | Re: [PATCH] rtc: rs5c372: Fix reading from rtc when the oscillator got interrupted. |
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On 06/02/2019 06:33:39+0000, Oliver.Rohe@wago.com wrote: > >> + switch (rs5c->type) { > >> + case rtc_r2025sd: > >> + case rtc_r2221tl: > >> + if (ctrl2 & R2x2x_CTRL2_VDET) > >> + dev_warn(&client->dev, "rtc battery voltage drop below threshold detected.\n"); > > > > VDET doesn't mean anything specific regarding timekeeping so I wouldn't warn here. > > VDET means in case the chip is powered by a battery, that is about to die sometime soon, it gives you heads up.
Yes but my statement stands true, this doesn't have any direct implication regarding timekeeping.
There is the RTC_VL_READ ioctl to check voltage low. It is not weel designed but this is what we have now.
> > > >> + if (ctrl2 & R2x2x_CTRL2_PON) > >> + dev_warn(&client->dev, "rtc battery voltage drop to zero detected.\n"); > > > > You should return -EINVAL directly here > > The PON implies the XSTP bit, so I only return from there, just to print all the warning messages, but I can return directly from here if you want.
As you said, PON implies XSTP so I'm not sure it is valuable to have both warnings.
-- Alexandre Belloni, Bootlin Embedded Linux and Kernel engineering https://bootlin.com
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