Re: [PATCH V11 3/5] kbuild: Allow .dtso format for overlay source files

From: Masahiro Yamada <masahiroy@kernel.org>
To: Geert Uytterhoeven <geert@linux-m68k.org>
Cc: Frank Rowand <frowand.list@gmail.com>,
	Laurent Pinchart <laurent.pinchart@ideasonboard.com>,
	Viresh Kumar <viresh.kumar@linaro.org>,
	Michal Marek <michal.lkml@markovi.net>,
	Vincent Guittot <vincent.guittot@linaro.org>,
	David Gibson <david@gibson.dropbear.id.au>,
	Michal Simek <michal.simek@xilinx.com>,
	Anmar Oueja <anmar.oueja@linaro.org>,
	Bill Mills <bill.mills@linaro.org>,
	Geert Uytterhoeven <geert+renesas@glider.be>,
	Linux Kbuild mailing list <linux-kbuild@vger.kernel.org>,
	Linux Kernel Mailing List <linux-kernel@vger.kernel.org>
Subject: Re: [PATCH V11 3/5] kbuild: Allow .dtso format for overlay source files
Date: Fri, 9 Apr 2021 15:03:05 +0900	[thread overview]
Message-ID: <CAK7LNASwMrWC2GWUVv-WEDVBvi4tJXM2ko++UXBEzsskAP_Uqw@mail.gmail.com> (raw)
In-Reply-To: <CAMuHMdWCUQRwUy3s_ApH8Pzafdvh61VRNkMcbZ0OnGcqtJxdkw@mail.gmail.com>

On Tue, Mar 16, 2021 at 5:01 PM Geert Uytterhoeven <geert@linux-m68k.org> wrote:
>
> Hi Frank,
>
> On Tue, Mar 16, 2021 at 6:39 AM Frank Rowand <frowand.list@gmail.com> wrote:
> > On 3/15/21 5:12 PM, Laurent Pinchart wrote:
> > > On Tue, Mar 16, 2021 at 02:43:45AM +0900, Masahiro Yamada wrote:
> > >> But how can we fix drivers/gpu/drm/rcar-du/rcar_du_of_lvds_r8a779*.dts
> > >> if these are doing bad things.
> > >> They seem to be overlay files even though the file name suffix is .dts
> > >
> > > That is correct, they are overlays. I have no issue with those files
> > > being renamed to .dtso if that can help (but I haven't checked if that
> > > would have any adverse effect on the R-Car DU driver).
> >
> > As Laurent replied, yes these are overlays.  They were grandfathered in
> > as a deprecated use of overlays.
> >
> > > These files are there to ensure backward compatibility with older DT
> > > bindings. The change was made 3 years ago and I wouldn't object to
> > > dropping this completely, but I understand I may not be the most
> > > cautious person when it comes to ensuring DT backward compatibility :-)
> >
> > My memory is that the goal was to eventually remove these overlays
> > at some point in the future.  If everyone agrees that today is the
> > proper time, it would be helpful to go ahead and remove these .dts
> > files and the code that uses them.
>
> Given [1][2][3] were merged in v4.17, and [4] was merged in v4.20, and
> all were backported to the old v4.14-based R-Car BSP v3.8.0, I think
> it's safe to assume all users have the DTS updates, so the backward
> compatibility mode can be removed?
>
> > >> drivers/gpu/drm/rcar-du/rcar_du_of_lvds_r8a7791.dts
> > >> drivers/gpu/drm/rcar-du/rcar_du_of_lvds_r8a7795.dts
> > >> drivers/gpu/drm/rcar-du/rcar_du_of_lvds_r8a7796.dts
> > >> drivers/gpu/drm/rcar-du/rcar_du_of_lvds_r8a7793.dts
> > >> drivers/gpu/drm/rcar-du/rcar_du_of_lvds_r8a7790.dts
>
> [1] 15a1ff30d8f9bd83 ("ARM: dts: r8a7790: Convert to new LVDS DT bindings")
> [2] e5c3f4707f3956a2 ("ARM: dts: r8a7791: Convert to new LVDS DT bindings")
> [3] edb0c3affe5214a2 ("ARM: dts: r8a7793: Convert to new LVDS DT bindings")
> [4] 58e8ed2ee9abe718 ("arm64: dts: renesas: Convert to new LVDS DT bindings")

Can we remove all of drivers/gpu/drm/rcar-du/*.dts ?

I see some more under drivers/staging/.

masahiro@grover:~/ref/linux-next$ find  drivers  -name  '*.dts'  |
grep -v drivers/of/unittest-data
drivers/staging/pi433/Documentation/devicetree/pi433-overlay.dts
drivers/staging/mt7621-dts/gbpc2.dts
drivers/staging/mt7621-dts/gbpc1.dts
drivers/gpu/drm/rcar-du/rcar_du_of_lvds_r8a7791.dts
drivers/gpu/drm/rcar-du/rcar_du_of_lvds_r8a7795.dts
drivers/gpu/drm/rcar-du/rcar_du_of_lvds_r8a7796.dts
drivers/gpu/drm/rcar-du/rcar_du_of_lvds_r8a7793.dts
drivers/gpu/drm/rcar-du/rcar_du_of_lvds_r8a7790.dts

Best Regards

Masahiro Yamada