Re: [PATCH v2] ARM: omap3: beagleboard-xm: dt: Add ethernet to the device tree

[Rob Herring <robh-DgEjT+Ai2ygdnm+yROfE0A@public.gmane.org>]

On Thu, Jan 5, 2017 at 10:48 AM, Laurent Pinchart
<laurent.pinchart-ryLnwIuWjnjg/C1BVhZhaw@public.gmane.org> wrote:
> Hello,
>
> On Thursday 05 Jan 2017 08:39:29 Tony Lindgren wrote:
>> * Rob Herring <robh-DgEjT+Ai2ygdnm+yROfE0A@public.gmane.org> [170105 08:28]:
>> > On Fri, Dec 2, 2016 at 3:11 PM, Laurent Pinchart wrote:
>> >> The Beagleboard-xM has a LAN9514 USB hub and ethernet controller,
>> >> connected to port 2 of the OMAP EHCI controller. The board however has
>> >> no EEPROM to store the ethernet MAC address, which is programmed by the
>> >> boot loader.
>> >>
>> >> To allow Linux to use the same MAC address as the boot loader (or for
>> >> that matter any fixed MAC address), we need a node in the device tree
>> >> for the ethernet controller that the boot loader can update at runtime
>> >> with a local-mac-address property. Add it, along with an alias for the
>> >> ethernet controller to let the boot loader locate it easily.
>> >>
>> >> Signed-off-by: Laurent Pinchart <laurent.pinchart-ryLnwIuWjnjg/C1BVhZhaw@public.gmane.org>
>> >> ---
>> >> Changes since v1:
>> >>
>> >> - Renamed usb2 DT node to hub
>> >> ---
>> >>
>> >>  arch/arm/boot/dts/omap3-beagle-xm.dts | 16 ++++++++++++++++
>> >>  1 file changed, 16 insertions(+)
>> >>
>> >> diff --git a/arch/arm/boot/dts/omap3-beagle-xm.dts
>> >> b/arch/arm/boot/dts/omap3-beagle-xm.dts index
>> >> 85e297ed0ea1..673cee2234b2 100644
>> >> --- a/arch/arm/boot/dts/omap3-beagle-xm.dts
>> >> +++ b/arch/arm/boot/dts/omap3-beagle-xm.dts
>> >> @@ -27,6 +27,7 @@
>> >>         aliases {
>> >>                 display0 = &dvi0;
>> >>                 display1 = &tv0;
>> >> +               ethernet = &ethernet;
>> >
>> > Sorry, just noticed this, but this should be dropped. It's not used
>> > nor do we want an alias here.
>>
>> OK, will update locally as I have not pushed out yet.
>
> The ethernet alias is used by U-Boot to locate the ethernet controller and
> update the MAC address.

Okay. Though with only only one, I don't see why that is hard to find.
Anyway, this is the least of u-boot's DT abuses.

>> > P.S. The display ones are questionable, too. Only OMAP has them and
>> > per platform alias names is not something we want.
>>
>> OK. What about the mmc ones? Otherwise the MMC devices keep moving
>> around depending on the kernel version..

This is a solved problem. Consistent dev numbering is not a feature of
the kernel and MMC is not special.

Rob
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