RE: [PATCH v2 5/6] PCI: dwc: rcar-gen4: Add support for other R-Car Gen4 PCIe controller

[Yoshihiro Shimoda <yoshihiro.shimoda.uh@renesas.com>]

Hi Bjorn,

> From: Bjorn Helgaas, Sent: Thursday, March 28, 2024 3:15 AM
> 
> On Wed, Mar 27, 2024 at 05:32:57AM +0000, Yoshihiro Shimoda wrote:
> > > From: Bjorn Helgaas, Sent: Wednesday, March 27, 2024 5:49 AM
> 
> > > >  static int rcar_gen4_pcie_get_resources(struct rcar_gen4_pcie *rcar)
> > > >  {
> > > > +	rcar->phy_base = devm_platform_ioremap_resource_byname(rcar->pdev, "phy");
> > > > +	if (IS_ERR(rcar->phy_base))
> > > > +		return PTR_ERR(rcar->base);
> > >
> > > I don't get it.  This imposes a new requirement (presence of "phy"
> > > resource) on the existing SoCs.  That doesn't sound right.
> >
> > According to the dt-binding doc, the existing SoCs are also required
> > for the "phy".  That's why I didn't add any condition to simplify
> > the code.
> 
> Is there anything that enforces that?  Is it possible that DTs exist
> in the field without it?  We don't want to break any existing setup.

Using make dtbs_check can detect an error if the "phy" doesn't exist like below:

/home/shimoda/development/linux/linux/arch/arm64/boot/dts/renesas/r8a779f0-spider.dtb: pcie@e65d0000: reg-names:5: 'phy' was expected
        from schema $id: http://devicetree.org/schemas/pci/rcar-gen4-pci-host.yaml#

So, I believe that this can enforce that in review process at least.
Now arch/arm64/boot/dts/renesas/r8a779f0.dtsi has the pcie compatible,
and all pcie nodes in the dtsi have "phy". So, this patch will not break any existing setup.

Best regards,
Yoshihiro Shimoda