Re: [PATCH 09/21] arm64: dts: qcom: sc8280xp: Add PCIe bridge node
From: Manivannan Sadhasivam
Date: Mon Mar 18 2024 - 01:25:00 EST
On Sun, Mar 17, 2024 at 10:37:15PM -0500, Bjorn Andersson wrote:
> On Thu, Feb 22, 2024 at 11:09:58AM +0530, Manivannan Sadhasivam wrote:
> > On Wed, Feb 21, 2024 at 01:39:01PM +0100, Konrad Dybcio wrote:
> > > On 21.02.2024 04:41, Manivannan Sadhasivam wrote:
> > > > On Qcom SoCs, the PCIe host bridge is connected to a single PCIe bridge
> > > > for each controller instance. Hence, add a node to represent the bridge.
> > > >
> > > > While at it, let's remove the bridge properties from board dts as they are
> > > > now redundant.
> > > >
> > > > Signed-off-by: Manivannan Sadhasivam <manivannan.sadhasivam@xxxxxxxxxx>
> > > > ---
> > > > .../dts/qcom/sc8280xp-lenovo-thinkpad-x13s.dts | 8 -----
> > > > arch/arm64/boot/dts/qcom/sc8280xp.dtsi | 40 ++++++++++++++++++++++
> > > > 2 files changed, 40 insertions(+), 8 deletions(-)
> > > >
> > > > diff --git a/arch/arm64/boot/dts/qcom/sc8280xp-lenovo-thinkpad-x13s.dts b/arch/arm64/boot/dts/qcom/sc8280xp-lenovo-thinkpad-x13s.dts
> > > > index def3976bd5bb..f0a0115e08fa 100644
> > > > --- a/arch/arm64/boot/dts/qcom/sc8280xp-lenovo-thinkpad-x13s.dts
> > > > +++ b/arch/arm64/boot/dts/qcom/sc8280xp-lenovo-thinkpad-x13s.dts
> > > > @@ -733,14 +733,6 @@ &pcie4 {
> > > > status = "okay";
> > > >
> > > > pcie@0 {
> > > > - device_type = "pci";
> > > > - reg = <0x0 0x0 0x0 0x0 0x0>;
> > > > - #address-cells = <3>;
> > > > - #size-cells = <2>;
> > > > - ranges;
> > > > -
> > > > - bus-range = <0x01 0xff>;
> > > > -
> > > > wifi@0 {
> > >
> > > This doesn't seem right, pleas use a label
> > >
> >
> > Why? A node label is useful if we want to reference it at the root level in
> > board dts, but here it is not.
> >
>
> Giving the bridge a label and then adding wifi@0 as a child using that
> label in the dts is pretty much how we do for everything else.
>
> I find this over-flattening hard to follow, but relying on child node
> names when extending the structure or adding properties have bitten us
> many times in the past.
>
> As such, I think the desired result in the dts should be:
>
> &pcie4 {
> status = "okay";
> };
>
> &pcie4_bridge {
> wifi@0 {
> ...
> };
> };
>
Ok. Will change it in next version. I'm also waiting to conclude on representing
the PERST# and WAKE# properties properly in the schema [1]. Once that gets
finalized, I'll respin v2.
- Mani
[1] https://github.com/devicetree-org/dt-schema/pull/126
> Regards,
> Bjorn
>
> > - Mani
> >
> > --
> > மணிவண்ணன் சதாசிவம்
--
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