On Fri, Mar 12, 2010 at 3:36 PM, David Gibson
[off-list ref] wrote:

On Fri, Mar 12, 2010 at 05:14:56AM -0700, Grant Likely wrote:

quoted

2010/3/11 N=E9meth M=E1rton [off-list ref]:

[snip]

quoted

quoted

+
+ =A0 =A0 =A0 cpus {
+ =A0 =A0 =A0 =A0 =A0 =A0 =A0 #address-cells =3D <1>;
+ =A0 =A0 =A0 =A0 =A0 =A0 =A0 #size-cells =3D <0>;
+
+ =A0 =A0 =A0 =A0 =A0 =A0 =A0 cpu@0 {
+ =A0 =A0 =A0 =A0 =A0 =A0 =A0 =A0 =A0 =A0 =A0 device_type =3D "cpu";
+ =A0 =A0 =A0 =A0 =A0 =A0 =A0 =A0 =A0 =A0 =A0 compatible =3D "PowerPC,=

5554";

quoted

I'd rather see the same convention used here as for all the other
compatible values in this file. =A0ie:

compatible =3D "fsl,mpc5554-e200z6", "fsl,powerpc-e200z6";

Dave, what do you think?

Well, you could add those too, but "PowerPC,5554" should probably
remain.

The historical background here is that in the original OF spec, driver
matching was done on node name, and only then on compatible.
Essentially the node name was treated as an implicit first entry in
the compatible list. =A0The the generic names convention came along, and
instead name became a human readable generic type for the device
("ethernet", "i2c", etc..).

That convention has been widely used since long before flat trees
existed, but for some reason it was never really used for cpu nodes;
they remained as "PowerPC,XXXX" or whatever. =A0Because the varying
names of cpu nodes was sometimes awkward to deal with in bootloaders,
we decided it would be sensible to apply the generic names convention
here too, so "cpu@X". =A0But then, the previous node name, which was
treated as being prepended to compatible, should now explicitly be put
into compatible.

In this particular case, we're talking about a part that has never
previously been described in a device tree.  So, since this is
something entirely new, what is the value in preserving the
PowerPC,XXXX style when there isn't any code that will be relying on
it?

g.

--=20
Grant Likely, B.Sc., P.Eng.
Secret Lab Technologies Ltd.