linux-kernel - Re: [PATCH 2/4] rtc: s3c: Add time range

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Date:   Tue, 19 Oct 2021 19:31:55 +0300
From:   Sam Protsenko <semen.protsenko@...aro.org>
To:     Alexandre Belloni <alexandre.belloni@...tlin.com>
Cc:     Alessandro Zummo <a.zummo@...ertech.it>,
        Krzysztof Kozlowski <krzysztof.kozlowski@...onical.com>,
        linux-rtc@...r.kernel.org,
        Linux Samsung SOC <linux-samsung-soc@...r.kernel.org>,
        Linux Kernel Mailing List <linux-kernel@...r.kernel.org>
Subject: Re: [PATCH 2/4] rtc: s3c: Add time range

On Tue, 19 Oct 2021 at 19:20, Alexandre Belloni
<alexandre.belloni@...tlin.com> wrote:
>
> On 19/10/2021 16:17:22+0300, Sam Protsenko wrote:
> > This RTC driver only accepts dates from 2000 to 2099 year. It starts
> > counting from 2000 to avoid Y2K problem, and S3C RTC only supports 100
> > years range. Provide this info to RTC framework.
> >
> > Signed-off-by: Sam Protsenko <semen.protsenko@...aro.org>
> > ---
> >  drivers/rtc/rtc-s3c.c | 2 ++
> >  1 file changed, 2 insertions(+)
> >
> > diff --git a/drivers/rtc/rtc-s3c.c b/drivers/rtc/rtc-s3c.c
> > index 10e591794276..d9994efd70ef 100644
> > --- a/drivers/rtc/rtc-s3c.c
> > +++ b/drivers/rtc/rtc-s3c.c
> > @@ -454,6 +454,8 @@ static int s3c_rtc_probe(struct platform_device *pdev)
> >       }
> >
> >       info->rtc->ops = &s3c_rtcops;
> > +     info->rtc->range_min = RTC_TIMESTAMP_BEGIN_2000;
> > +     info->rtc->range_max = RTC_TIMESTAMP_END_2099;
> >
>
> This change is missing the if (year < 0 || year >= 100)  removal in
> s3c_rtc_settime()
>

It's not actually removed in [PATCH 3/4] (if I'm following you
correctly), it was replaced with this code:

<<<<<<<<<<<<<<<<<<<<<<< cut here >>>>>>>>>>>>>>>>>>>
    if (rtc_tm.tm_year < 0 || rtc_tm.tm_year >= 100) {
        dev_err(dev, "rtc only supports 100 years\n");
        return -EINVAL;
    }
<<<<<<<<<<<<<<<<<<<<<<< cut here >>>>>>>>>>>>>>>>>>>

But [PATCH 3/4] is mostly needed for [PATCH 4/4], so you can drop it
if you don't like it. Or it might be kept as a cleanup.

+
+    if (rtc_tm.tm_year < 0 || rtc_tm.tm_year >= 100) {
+        dev_err(dev, "rtc only supports 100 years\n");
+        return -EINVAL;
+    }

> >       ret = devm_rtc_register_device(info->rtc);
> >       if (ret)
> > --
> > 2.30.2
> >
>
> --
> Alexandre Belloni, co-owner and COO, Bootlin
> Embedded Linux and Kernel engineering
> https://bootlin.com