Re: [PATCH dt + pci 1/2] dt-bindings: Add 'slot-power-limit-milliwatt' PCIe port property

Pali Rohár
2021-11-12T15:32:12Z

On Friday 12 November 2021 09:25:20 Rob Herring wrote:
> On Sun, Oct 31, 2021 at 04:07:05PM +0100, Marek Behún wrote:
> > + If present, this property specifies slot power limit in milliwatts. Host
> > + drivers can parse this property and use it for programming Root Port or host
> > + bridge, or for composing and sending PCIe Set_Slot_Power_Limit messages
> > + through the Root Port or host bridge when transitioning PCIe link from a
> > + non-DL_Up Status to a DL_Up Status.
>
> If your slots are behind a switch, then doesn't this apply to any bridge
> port?

The main issue here is that pci.txt (and also scheme on github) is
mixing host bridge and root ports into one node. This new property
should be defined at the same place where is supports-clkreq or
reset-gpios, as it belongs to them.

And you are right, that this new property should be defined only for
root ports and downstream ports of switch.