[PATCH v2 6/7] Holly DTS
Segher Boessenkool
segher at kernel.crashing.org
Sun May 6 06:44:12 EST 2007
>>> +/ {
>>> + model = "ppc750-tsi109";
>>
>> "model" should be something really specific; typically
>> a (unique!) model number. This means you can't use the
>> same device tree for Holly and Hickory (but there are
>> more reasons for that; see below).
>>
>>> + compatible = "ppc750-tsi";
>>
>> The needs to be more specific as well; "ibm,holly"
>> or something.
>
> Why? Holly and Hickory share the same memory map and devices. The
> only
> thing that differs from what I can tell is the actual CPU itself.
And the model number I suspect.
"ppc750-tsi" really isn't good enough as a "compatible"
property, there are many many more boards with some 750
and some TSI bridge.
>>> + tsi109 at c0000000 {
>>> + device_type = "tsi-bridge";
>>
>> Don't put a "device_type" here, it is useless
>> (and undefined). There are more like this, but
>> perhaps Linux (wrongly) probes on "device_type"
>> for those, so the kernel would need updating
>> first.
>
> It's not useless. The TSI code probes by device_type all over the
> place. Do you have an example of how to probe for something like this
> without using device_type?
Sure: use "compatible" instead.
This problem is all over the place, don't worry
about it too much. It would be good if new ports
could stop adding to the madness though ;-)
>>> + MPIC: pic at 7400 {
>>> + built-in;
>>
>> Why say this for MPIC only, not for most other nodes?
>> What binding defines "built-in", anyway?
>
> http://playground.sun.com/1275/bindings/chrp/chrp1_8a.ps
But this isn't a CHRP compatible board, that binding
doesn't apply.
Segher
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