[PATCHv4 3/6] ARM: dts: Add initial LS1021A TWR board dts support

-----Original Message-----
From: Arnd Bergmann [mailto:arnd at arndb.de]
Sent: Wednesday, September 24, 2014 11:55 PM
To: Lu Jingchang-B35083
Cc: Guo Shawn-R65073; mark.rutland at arm.com; linux-arm-
kernel at lists.infradead.org; devicetree at vger.kernel.org; Lu Chen-B46807; Fu
Chao-B44548
Subject: Re: [PATCHv4 3/6] ARM: dts: Add initial LS1021A TWR board dts
support

On Wednesday 24 September 2014 11:00:34 Jingchang Lu wrote:

quoted

We also do the phy-handle fixup on our PowerPC platform based on the
aliases, and so I adopt the same way to make these fixup consistent

between SoCs.

quoted

And the u-boot fdt fixup code base on the aliases has been upstreamed,
so may we keep this aliases unchanged?

I don't see a strong reason to change it, it just seemed strange to me.

quoted

BTW, find a node by alias is easily, could you give me some clue on
finding a node by a label directly, Thanks.

I haven't used libfdt in this way myself, so I don't know how it would be
done. However, the idea is that the labels in dts files end up as ELF
symbols in the dtb, so you can look them up by following the ELF headers.

Arnd

Libfdt doesn't provide way to find a node by label. Label is just a shortcut to
a full absolute path, it's useful in device tree source reference, but is hard
to find a label after build to dtb. Aliases just provide the way to save a
full absolute path in properties like label, but they can be find in dtb after
build so that fixup on dtb can find a node efficiently. So I think the aliases
for the phy nodes is also reasonable. Many others boards also use labels for
various dts nodes.
Thanks.

Best Regards,
Jingchang