Subject: Re: [RFC] Device tree for new desktop platform in arch/powerpc

From: Segher Boessenkool <[email-masked]>
Date: Thu, 21 Jun 2007 16:24:17 +0200

>> 3. The dts files define the device_type of a serial port as "serial",
>> whereas the OF spec says "pnpPNP,501". What's the difference between
>> the two?
>
> Use the pnp stuff for "compatible", you can mostly ignore device_type 
> or
> set it to the same as name.

Only if the name is indeed the correct, defined, device_type
for that device, and you implement the whole binding for that
device_type (I recommend you do, for serial; it makes it
easier to use that device as an early console).

>> 4. I couldn't find any information for a device tree representation of
>> the i8259 interrupt controller in the booting-without-of.txt file. Is
>> my implementation correct (inspired by the OF documents)?
>
> Haven't looked at your .dts yet but it should be 
> "interrupt-controller",
> compatible "chrp,iic" or "i8259", with a #interrupt-cells of 2 and
> interrupts following the standard ISA encoding. You probably also want
> an interrupt-parent property in the isa bridge node pointing back to 
> the
> 8259 so it becomes the default for all ISA devices.

Yeah.  You can also use the "pnpPNP," name for the 8259 if
it is hooked up like on a PC.

>> I would be grateful, if you could take a look at my dts file and
>> comment on every line that doesn't meet your views.

Please send a new .dts based on the comments you've had so far?

Segher