[PATCH 1/4] PCI: add DT bindings for Faraday Technology PCI Host Bridge

Linus Walleij linus.walleij at linaro.org
Sun Feb 26 12:17:46 PST 2017


On Wed, Feb 22, 2017 at 1:26 AM, Rob Herring <robh at kernel.org> wrote:
> On Sat, Feb 11, 2017 at 01:52:17PM +0100, Linus Walleij wrote:

>> +- compatible: should be one of
>> +  "faraday,pci"
>> +  "faraday,dual-pci"
>
> Probably should still have a Cortina specific compatible.

OK I rewrote it using the specific-to-generic compatible pattern.

>> +pci at 50000000 {
>> +     compatible = "faraday,pci";
>> +     reg = <0x50000000 0x100>;
>> +     interrupts = <8 IRQ_TYPE_LEVEL_HIGH>, /* PCI A */
>> +                     <26 IRQ_TYPE_LEVEL_HIGH>, /* PCI B */
>> +                     <27 IRQ_TYPE_LEVEL_HIGH>, /* PCI C */
>> +                     <28 IRQ_TYPE_LEVEL_HIGH>; /* PCI D */
>> +     #address-cells = <3>;
>> +     #size-cells = <2>;
>> +     #interrupt-cells = <1>;
>
> This doesn't belong here (I think).

This needs to be here because the interrupts for
PCI are 1 cell. The PCI host acts as interrupt parent for all
the cards you plug in, and they always have one cell, you
can see this in the example for open-pic in Device Tree
Specification release 0.1, page 19 for example.

It gets a bit confusing maybe in cases like this (as with
open-pic) where there is a cascades interrupt controller
that in this case also has 1 cell of interrupt specifier.

Or did you mean something else?

Yours,
Linus Walleij



More information about the linux-arm-kernel mailing list