[PATCH 1/6] ARM: sunxi: DT: Convert to device tree includes

Maxime Ripard maxime.ripard at free-electrons.com
Wed Dec 17 13:33:58 PST 2014

Hi Arnd,

On Wed, Dec 17, 2014 at 08:32:01AM +0100, Arnd Bergmann wrote:
> On Tuesday 16 December 2014 22:59:54 Maxime Ripard wrote:
> > Prepare the device trees to use the C preprocessor.
> > 
> > Signed-off-by: Maxime Ripard <maxime.ripard at free-electrons.com>
> Hi Maxime,
> Since you are doing a number of changes to all the sunxi files, I have
> one more request for something that has been bugging me a while:
> In your .dtsi files, you define devices like this:
>                 uart0: serial at 01c28000 {
>                         compatible = "snps,dw-apb-uart";
>                         reg = <0x01c28000 0x400>;
>                         interrupts = <0 1 4>;
>                         reg-shift = <2>;
>                         reg-io-width = <4>;
>                         clocks = <&apb1_gates 16>;
>                         status = "disabled";
>                 };
> and in the .dts files, you extend them like this:
>                 uart0: serial at 01c28000 {
>                         pinctrl-names = "default";
>                         pinctrl-0 = <&uart0_pins_a>;
>                         status = "okay";
>                 };
> which duplicates both the node names with their full path, and
> the labels. Please use one or the other, but not both. I don't mind
> you having the full path to each device in the dts files, just drop
> all the labels in that case.

I don't know, maybe it's just a matter of personnal taste, but I do
find convenient to have the labels in the DTS as well, so that
whenever you need to use a label (for a phandle for example), you
don't have to lookup in the DTSI if you have the node in the DTS.

> Most other maintainers these days just use the labels like this in
> the dts files however:
> &uart0 {
> 	status = "okay";
> };
> which also seems completely fine.

If that's the current trend, I'll add that to my todo-list, but I
believe it's orthogonal to these patches.

> I'm also a bit puzzled by all the pinctrl references you add in the .dts
> files, but it's possible I'm missing something there. Why can't you move
> these to the .dtsi files and avoid duplicating the pinctrl-0 and
> pinctrl-names properties for every .dts file? I would assume that they
> are not referenced for disabled devices.

The pinctrl nodes we reference are in the DTS. However, each pin of
each controller is most of the time available on several pins of the
package, so we don't have any way to enforce a default at the SoC


Maxime Ripard, Free Electrons
Embedded Linux, Kernel and Android engineering
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