Re: [PATCH 2/2] ARM: dts: berlin: add GPIO nodes for the BG2Q

[Sebastian Hesselbarth]

On 04/15/2014 12:00 PM, Jisheng Zhang wrote:
> On Tue, 15 Apr 2014 02:23:03 -0700
> Sebastian Hesselbarth <sebastian.hesselbarth@xxxxxxxxx> wrote:
> > On 04/15/2014 10:07 AM, Antoine TÃnart wrote:
> > > The Marvell Berlin BG2Q has 6 GPIO ports compatible with the
> > > snps,dw-apb-gpio driver. This patch add the corresponding device tree
> > > nodes.
> > >
> > > Signed-off-by: Antoine TÃnart <antoine.tenart@xxxxxxxxxxxxxxxxxx>
> > > ---
> > >    arch/arm/boot/dts/berlin2q.dtsi | 102
> > > ++++++++++++++++++++++++++++++++++++++++ 1 file changed, 102 insertions(+)
> > >
> > > diff --git a/arch/arm/boot/dts/berlin2q.dtsi
> > > b/arch/arm/boot/dts/berlin2q.dtsi index e6e556055dfc..b2625f896bc5 100644
> > > --- a/arch/arm/boot/dts/berlin2q.dtsi
> > > +++ b/arch/arm/boot/dts/berlin2q.dtsi
[...]
> > > +					compatible =
> > > "snps,dw-apb-gpio-port";
> > > +					gpio-controller;
> > > +					#gpio-cells = <2>;
> > > +					snps,nr-gpios = <32>;
> >
> > 32 gpio pins for each of the 6 GPIO controllers? Either BG2Q is a GPIO
>
> Yes, BG2Q support 32 pins every port

Wow. Thanks for confirming this!

> > I am fine with using nr-gpios property now, but I guess BG2Q also
> > has that CONFIG[1,2] registers to actually read out the features
> > synthesized in? If I find some time, I'll prepare a patch for
> > dw-apb-gpio to exploit that (optional) information instead of
> > using nr-gpios.
>
> The problem is CONFIG1/2 registers don't exist on some versions.
> For example, the version used in BG2/BG2CD. So nr-gpio is necessary
> if we want to support these versions.

Hmm, are you sure about BG2? I remember reading it and it contains
sane values. Anyway, a proper patch for dw-apb-gpio would include
checking for sane (e.g. non-zero) values. And nr-gpios will always
stay as fall-back just because e.g. sunxi does not have the CONFIG
registers.

Sebastian

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