Re: [PATCH] arm/dt: tegra devicetree support

From: Shawn Guo
Date: Wed Jul 20 2011 - 18:42:25 EST


On Wed, Jul 20, 2011 at 08:37:19AM -0700, Stephen Warren wrote:
> Grant Likely wrote at Tuesday, July 19, 2011 5:43 PM:
> > Everything required to populate NVIDIA Tegra devices from the device
> > tree. This patch adds a new DT_MACHINE_DESC() which matches against
> > a tegra20 device tree. So far it only registers the on-chip devices,
> > but it will be refined in follow on patches to configure clocks and
> > pin IO from the device tree also.
> >
> > Signed-off-by: Grant Likely <grant.likely@xxxxxxxxxxxx>
> > ---
> >
> > Hi all,
> >
> > Similar to the versatile patch I just posted, this is certainly not
> > complete board support, but it is enough to be useful. I'd like to
> > merge this for v3.1. It should not break any existing board support.
>
> > diff --git a/arch/arm/boot/dts/tegra-harmony.dts b/arch/arm/boot/dts/tegra-harmony.dts
>
> tegra-*.dts don't include status="disable" for all the unused controllers.
> Should that be added?
>
> > + sound {
> > + compatible = "nvidia,harmony-sound", "nvidia,tegra-wm8903";
>
> I thought the sound bindings were still somewhat experimental and not
> completely agreed upon. One issue I see is that Device Tree is
> supposed to represent pure HW, rather than driver-required abstractions,
> and at least the compatible name here is pretty Linux-driver-specific.
>
> I think there are some devices missing from the DT file for audio too,
> e.g. the ALSA "PCM" (DMA) driver.
>
> Also, the bindings for this aren't documented IIRC.
>
> I'd suggest dropping the audio part of the DT file until the audio side
> is more mature.
>
> > + spkr-en-gpios = <&codec 2 0>;
>
> Should that be "gpio" not "gpios", since there is only one?
>
My reason for using "gpios" over "gpio" is that
Documentation/devicetree/bindings/gpio/gpio.txt says so. Unless you
want to change the document to elaborate the difference between "gpio"
and "gpios", which I do not see the necessity ...

GPIO properties should be named "[<name>-]gpios".

Regards,
Shawn

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