Re: [PATCH] arm64: dts: renesas: spider: Add overlay for PCIe ch0 endpoint mode

[Koichiro Den]

On Mon, Oct 26, 2026 at 06:35:09AM +0100, Marek Vasut wrote:
> On 10/26/26 4:08 AM, Koichiro Den wrote:
> > On Fri, Oct 23, 2026 at 02:58:38AM +0200, Marek Vasut wrote:
> > > On 10/22/26 10:21 AM, Koichiro Den wrote:
> > > 
> > > Hello Den-san,
> > > 
> > > [...]
> > > 
> > > > +++ b/arch/arm64/boot/dts/renesas/r8a779f0-spider-pcie0-ep.dtso
> > > > @@ -0,0 +1,15 @@
> > > > +// SPDX-License-Identifier: (GPL-2.0 OR MIT)
> > > > +/*
> > > > + * Copyright (C) 2026 Renesas Electronics Corp.
> > > 
> > > Is this header correct ?
> > 
> > I checked with Renesas just in case, and confirmed it is fine.
> 
> Thank you for checking.
> 
> > > Would it be possible to include a brief "example usage" comment in the
> > > header ? An example of such a comment is available in e.g.
> > > arch/arm64/boot/dts/renesas/r8a779g3-sparrow-hawk-fan-argon40.dtso "Example
> > > usage:" . If this would be too complicated, then please ignore this request.
> > 
> > I would personally perfer to stay aligned with other in-tree PCIe endpoint
> > overlays (e.g. freescale/imx*, rockchip/*, ti/k3-*) rather than adding
> > fan/HAT-style examples here.
> > 
> > The typical (long-standing) usage would just be the standard configfs steps for
> > pci-epf-test (documented in Documentation/PCI/endpoint/pci-test-howto.rst)
> 
> How about adding modified form of this ^ sentence into the header ?
> (please see below)
> 
> > , so I
> > suspect duplicating those generic instructions in this file might not add much
> > value.
> > 
> > That said, keeping the header completely bare might look too terse.
> > How about something like this:
> > 
> >    // SPDX-License-Identifier: (GPL-2.0 OR MIT)
> >    /*
> >     * DT Overlay for enabling PCIe channel 0 in Endpoint Configuration with the
> >     * R-Car S4-8 Spider board.
> >     *
> >     * Copyright (C) 2026 Renesas Electronics Corp.
> 
> How about adding this here:
> 
> *
> * Please follow the standard configfs steps for pci-epf-test documented in
> * Documentation/PCI/endpoint/pci-test-howto.rst to set the endpoint up.
> 
> This would steer users toward the documentation. What do you think ?

Fair enough. While I'd assume anyone enabling EP mode probably already knows
what they're doing, having a pointer to the doc certainly doesn't hurt any could
be a nice nudge for users. I have no objections at all.

I'll send v2 shortly, thank you!

Best regards,
Koichiro Den

> 
> [...]
> 
> -- 
> Best regards,
> Marek Vasut