On Wed, Feb 12, 2014 at 09:54:50AM +0000, Mark Rutland wrote:
> > I take it as an unnecessary churn, unless I see the consensus from most
> > of DT maintainers and arm-soc folks that we should make this change.
> > And see comment below ...
>
> My concern is that the simple-bus is being used in a nonsensical way,
> with a meaningless address space and reg values on children. While this
> currently works it is not correct, and it's not even necessary. I would
> like to limit the misuse of these constructs so as to prevent others
> from making the same mistakes.
Unfortunately, it's already been used quite widely. This is not IMX
specific, and you can grep arch/arm/boot/dts to get the idea. I'm not
sure if it's worth the churn to 'fix' it. In these days, arm-soc folks
are quite sensitive to the number of IMX patches and change sets. 50
LOC change for one board dts, and we now have ~70 files for IMX. That's
why I would like to get the agreement from arm-soc folks that we should
really make such change.
>
> >
> > >
> > > arch/arm/boot/dts/imx6qdl-sabresd.dtsi | 51 ++++++++++++++--------------------
> > > 1 file changed, 21 insertions(+), 30 deletions(-)
> > >
> > > diff --git a/arch/arm/boot/dts/imx6qdl-sabresd.dtsi b/arch/arm/boot/dts/imx6qdl-sabresd.dtsi
> > > index 0d816d3..d7df5b2 100644
> > > --- a/arch/arm/boot/dts/imx6qdl-sabresd.dtsi
> > > +++ b/arch/arm/boot/dts/imx6qdl-sabresd.dtsi
> > > @@ -18,38 +18,29 @@
> > > reg = <0x10000000 0x40000000>;
> > > };
> > >
> > > - regulators {
> > > - compatible = "simple-bus";
> > > - #address-cells = <1>;
> > > - #size-cells = <0>;
> > > -
> > > - reg_usb_otg_vbus: regulator@0 {
> > > - compatible = "regulator-fixed";
> > > - reg = <0>;
> > > - regulator-name = "usb_otg_vbus";
> > > - regulator-min-microvolt = <5000000>;
> > > - regulator-max-microvolt = <5000000>;
> > > - gpio = <&gpio3 22 0>;
> > > - enable-active-high;
> > > - };
> > > + reg_usb_otg_vbus: regulator@0 {
> >
> > nodename@num should only be used for nodes that have 'reg' property.
> > Why are you dropping 'reg' property here? Right, it does not compile if
> > you do not drop it. You can take it as a reason of why I endorse
> > simple-bus regulators container.
>
> I don't think the logical jump from "it does not compile" to "I endorse
> simple-bus regulators container" makes any sense. They're two separate
> issues.
You're right :)
>
> The unit-addresses and reg values can be dropped. They are not in the
> regulator-fixed binding, and were never necessary. All that's necessary
> is a unique name, and unit-addresses (which required a reg) were misused
> to provide uniqueness. With that fixed, this will compile.
IIRC, ePAPR recommends to use generic node name and have
unit-addresses for uniqueness. That's why I sent patch [1] to follow
the way that tegra and other platforms names them. Now you're
suggesting to go back?
Shawn
[1] http://www.spinics.net/lists/arm-kernel/msg284474.html
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