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

[Marek Vasut <marek.vasut@mailbox.org>]

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 ?

[...]

-- 
Best regards,
Marek Vasut