On Sat, Dec 30, 2017 at 12:50 AM, Rafael J. Wysocki <rafael@xxxxxxxxxx> wrote: > On Fri, Dec 29, 2017 at 6:57 PM, Tony Lindgren <tony@xxxxxxxxxxx> wrote: >> * Jeffy Chen <jeffy.chen@xxxxxxxxxxxxxx> [171226 02:11]: >>> We are going to handle PCIe WAKE# pin for PCI devices in the pci core, >>> so add definitions of the optional PCIe WAKE# pin for PCI devices. >>> >>> Also add an definition of the optional PCI interrupt pin for PCI >>> devices to distinguish it from the PCIe WAKE# pin. >> >>> --- a/Documentation/devicetree/bindings/pci/pci.txt >>> +++ b/Documentation/devicetree/bindings/pci/pci.txt >>> @@ -24,3 +24,13 @@ driver implementation may support the following properties: >>> unsupported link speed, for instance, trying to do training for >>> unsupported link speed, etc. Must be '4' for gen4, '3' for gen3, '2' >>> for gen2, and '1' for gen1. Any other values are invalid. >>> + >>> +PCI devices may support the following properties: >> >> This should say PCI ports instead of PCI devices. > > No, it is more accurate to say "PCI devices". > > Well, it actually gets somewhat confusing, because in the PCI > terminology a "PCI device" means a physical piece of hardware that can > be put into a single "slot" (think socket on a board) and may consist > up to 8 functional units called "functions" which are each represented > by a struct pci_dev. So there may be up to 8 struct pci_dev objects > per "PCI device" (as per the standard language) and, BTW, drivers bind > to functions (via the struct pci_dev objects). > > Now, WAKE# is shared by all functions within the same "PCI device" > (I'm not sure if the standard specifies that directly, but at least it > appears to be treated as an obvious physical limitation), so it may be > useful to represent the "slot" or "device" level in the DT even though > it has no struct device based representation in the kernel. Within the convention that bridges represent "everything below them" as far as WAKE# is concerned, it can say "The following properties may be provided for PCI bridges:" and the description below should explain the convention. Thanks, Rafael
