linux-kernel - Re: [PATCH 2/2] rtc: sprd: Add Spreadtrum RTC driver

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Message-ID: <20171108053522.qhoagssswonevae4@piout.net>
Date:   Wed, 8 Nov 2017 06:35:22 +0100
From:   Alexandre Belloni <alexandre.belloni@...e-electrons.com>
To:     Baolin Wang <baolin.wang@...aro.org>
Cc:     Baolin Wang <baolin.wang@...eadtrum.com>,
        Alessandro Zummo <a.zummo@...ertech.it>,
        Rob Herring <robh+dt@...nel.org>,
        Mark Rutland <mark.rutland@....com>,
        devicetree@...r.kernel.org, LKML <linux-kernel@...r.kernel.org>,
        linux-rtc@...r.kernel.org, Mark Brown <broonie@...nel.org>
Subject: Re: [PATCH 2/2] rtc: sprd: Add Spreadtrum RTC driver

On 08/11/2017 at 13:29:21 +0800, Baolin Wang wrote:
> > Don't do that. This is a valuable information. If you know the time is
> > invalid, return -EINVAL in read_time(). What your are doing here is
> > confusing the system by making it believe your fake date is the correct
> > time.
> 
> Usually for mobile device, we should give one reasonable start time if
> the RTC powered down. Anyway I can remove this feature now.
> Very appreciated for your helpful comments.

Then userspace will have -EINVAL when reading the RTC and will be able
to set the RTC to whatever value it wants. Don't encode that policy in
the kernel.


-- 
Alexandre Belloni, Free Electrons
Embedded Linux and Kernel engineering
http://free-electrons.com