Re: [0/14] Ebony support, 2nd spi

On Tuesday 20 February 2007 16:25, Segher Boessenkool wrote:

quoted

quoted

And the ebony dts also has the a bus type of "ibm,opb" as well.

We should really get a common name for these. I don't remember
what the discussions were, but it seems we came up with different
results for Axon and ppc4xx, which is very bad.

"Very bad"...  Well sure it's less than desirable, but
we have to deal with this problem anyway already.

quoted

Using type "ibm,opb" rather than just "opb" makes sense to me,
but I don't know if we already have shipping systems that use
"opb" here.

There is probably a similar problem with the nodes for "plb4",
"plb5" and "ebc",

It makes sense for generic code to always if it is asked
to match for "vendor-code,some-name" also to match on
plain "some-name".  Well unless people start doing crazy
things like naming something "vendor-code,pci" which
isn't PCI compatible or something -- in that case there
could be a function that matches on exact name only, or
the caller can deal with it itself perhaps.

But in most cases the matching-without-prefix should work
fine.

but is it really the right thing to call it "ibm,plb"
when the identical macro is used on amcc based systems?

I think that was our reasoning when we introduced the
code in linux to scan for "plb5", "plb4" and "opb" buses.

Changing the "device-type" now would result in the final
product to not work on the 2.6.20 kernel, which was released
with the code only scanning for the short names.

Still, it's probably a good idea to list both variants
in compatible, e.g.

type="plb4", compatible="ibm,plb\0ibm,plb4\0plb"

on CAB/axon, and

type="ibm,plb", compatible="ibm,plb4\0plb4\0plb"

on ebony and others. Do you think it makes sense to do it this
way, or should we rather adopt the axon style on the 440 boards?

quoted

as well as the "compatible" property of the
serial port, which, as you noted earlier is "ns16550" on
ebony and "ns16750" on axon, although it is exactly the same
macro.

So the "compatible" property should read ns16750, ns16550,
ns16450, i8250.  The kernel really only needs the device
to be compatible to the 8250; but since lots of device trees
mention only the newer UART types, you have to match on those
too.

Right, that sounds completely correct. I think I've done the
right thing in of_serial already. Christian, please check
what the firmware does today, and make sure to change it
accordingly.
We probably also need a volunteer to clean up the legacy_serial
code for this, it's grown pretty messy by now.

	Arnd <><