Re: [PATCH v4 2/3] ARM: dts: Update the status of RTC DT node of Exynos5250 SoC to "okay"

From: Tomasz Figa <tomasz.figa@gmail.com>
To: Tushar Behera <tushar.behera@linaro.org>
Cc: Vikas Sajjan <vikas.sajjan@linaro.org>,
	linux-samsung-soc <linux-samsung-soc@vger.kernel.org>,
	Kukjin Kim <kgene.kim@samsung.com>,
	Patch Tracking <patches@linaro.org>,
	linaro-kernel@lists.linaro.org,
	Doug Anderson <dianders@chromium.org>
Subject: Re: [PATCH v4 2/3] ARM: dts: Update the status of RTC DT node of Exynos5250 SoC to "okay"
Date: Thu, 15 Aug 2013 10:59:02 +0200	[thread overview]
Message-ID: <2856422.z0LmRpN0Wg@flatron> (raw)
In-Reply-To: <CAHbNUh3LG4coLDfGZ5b=agaJ0PhhAR0A3Nhq-tPyL78KekhFOw@mail.gmail.com>

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Hi Tushar,

On Thursday 15 of August 2013 10:02:43 Tushar Behera wrote:
> On 14 August 2013 19:28, Vikas Sajjan <vikas.sajjan@linaro.org> wrote:
> > Updates the RTC DT node's status to "okay", since the bindings in
> > exynos5250.dtsi depicts the RTC h/w completely.
> > 
> > Signed-off-by: Vikas Sajjan <vikas.sajjan@linaro.org>
> > ---
> > 
> >  arch/arm/boot/dts/exynos5250.dtsi |    1 +
> >  1 file changed, 1 insertion(+)
> > 
> > diff --git a/arch/arm/boot/dts/exynos5250.dtsi
> > b/arch/arm/boot/dts/exynos5250.dtsi index f426ce6..c82137b 100644
> > --- a/arch/arm/boot/dts/exynos5250.dtsi
> > +++ b/arch/arm/boot/dts/exynos5250.dtsi
> > @@ -181,6 +181,7 @@
> > 
> >         rtc@101E0000 {
> >         
> >                 clocks = <&clock 337>;
> >                 clock-names = "rtc";
> > 
> > +               status = "okay";
> > 
> >         };
> 
> Sometime back we had a discussion on this, the decision was to enable
> it in respective boards.

This is not entirely true.

According to ePAPR, chapter 2.3.4, the status property has a well defined 
meaning and it should be set to "disabled" when "the device is not 
presently operational, but it might become operational in the future (for 
example, something is not plugged in, or switched off)".

This means that unless setup of the device is missing something (e.g. 
board-specific properties, like regulators or pin config) or there is a 
valid technical reason for disabling the device by default (e.g. it needs 
certain SoC pins to be properly connected to something), then such device 
should be "okay", because it is operational.

> Also if we are going ahead with this, we would need to remove the
> corresponding status statements from board files.

Yes, this is true.

Best regards,
Tomasz

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