From: Maxime Ripard <maxime@cerno.tech>
To: Philipp Rossak <embed3d@gmail.com>
Cc: "H. Nikolaus Schaller" <hns@goldelico.com>,
"David Airlie" <airlied@linux.ie>,
"Daniel Vetter" <daniel@ffwll.ch>,
"Rob Herring" <robh+dt@kernel.org>,
"Mark Rutland" <mark.rutland@arm.com>,
"Benoît Cousson" <bcousson@baylibre.com>,
"Tony Lindgren" <tony@atomide.com>,
"Paul Cercueil" <paul@crapouillou.net>,
"Ralf Baechle" <ralf@linux-mips.org>,
"Paul Burton" <paulburton@kernel.org>,
"James Hogan" <jhogan@kernel.org>,
"Kukjin Kim" <kgene@kernel.org>,
"Krzysztof Kozlowski" <krzk@kernel.org>,
"Chen-Yu Tsai" <wens@csie.org>,
"Thomas Bogendoerfer" <tsbogend@alpha.franken.de>,
"open list:DRM PANEL DRIVERS" <dri-devel@lists.freedesktop.org>,
"open list:OPEN FIRMWARE AND FLATTENED DEVICE TREE BINDINGS"
<devicetree@vger.kernel.org>,
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"OpenPVRSGX Linux Driver Group" <openpvrsgx-devgroup@letux.org>,
"Discussions about the Letux Kernel"
<letux-kernel@openphoenux.org>,
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arm-soc <linux-arm-kernel@lists.infradead.org>,
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Subject: Re: [PATCH v6 00/12] ARM/MIPS: DTS: add child nodes describing the PVRSGX GPU present in some OMAP SoC and JZ4780 (and many more)
Date: Tue, 21 Apr 2020 13:21:29 +0200 [thread overview]
Message-ID: <20200421112129.zjmkmzo3aftksgka@gilmour.lan> (raw)
In-Reply-To: <b5a06c19-7a3e-bcb8-5ae3-76901b9c6c35@gmail.com>
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Hi,
On Tue, Apr 21, 2020 at 11:57:33AM +0200, Philipp Rossak wrote:
> On 20.04.20 09:38, Maxime Ripard wrote:
> > Hi,
> >
> > On Fri, Apr 17, 2020 at 02:09:06PM +0200, Philipp Rossak wrote:
> > > > > I'm a bit skeptical on that one since it doesn't even list the
> > > > > interrupts connected to the GPU that the binding mandates.
> > > >
> > > > I think he left it out for a future update.
> > > > But best he comments himself.
> > >
> > > I'm currently working on those bindings. They are now 90% done, but they are
> > > not finished till now. Currently there is some mainline support missing to
> > > add the full binding. The A83T and also the A31/A31s have a GPU Power Off
> > > Gating Register in the R_PRCM module, that is not supported right now in
> > > Mainline. The Register need to be written when the GPU is powered on and
> > > off.
> > >
> > > @Maxime: I totally agree on your point that a demo needs to be provided
> > > before the related DTS patches should be provided. That's the reason why I
> > > added the gpu placeholder patches.
> > > Do you have an idea how a driver for the R_PRCM stuff can look like? I'm not
> > > that experienced with the clock driver framework.
> >
> > It looks like a power-domain to me, so you'd rather plug that into the genpd
> > framework.
>
> I had a look on genpd and I'm not really sure if that fits.
>
> It is basically some bit that verify that the clocks should be enabled or
> disabled.
No, it can do much more than that. It's a framework to control the SoCs power
domains, so clocks might be a part of it, but most of the time it's going to be
about powering up a particular device.
> I think this is better placed somewhere in the clocking framework.
> I see there more similarities to the gating stuff.
> Do you think it is suitable to implement it like the clock gating?
I'm really not sure what makes you think that this should be modelled as a
clock?
> > > The big question is right now how to proceed with the A83T and A31s patches.
> > > I see there three options, which one do you prefer?:
> > >
> > > 1. Provide now placeholder patches and send new patches, if everything is
> > > clear and other things are mainlined
> > > 2. Provide now patches as complete as possible and provide later patches to
> > > complete them when the R_PRCM things are mainlined
> > > 3. Leave them out, till the related work is mainlined and the bindings are
> > > final.
> >
> > Like I said, the DT *has* to be backward-compatible, so for any DT patch that
> > you are asking to be merged, you should be prepared to support it indefinitely
> > and be able to run from it, and you won't be able to change the bindings later
> > on.
>
> I agree on your points. But is this also suitable to drivers that are
> currently off tree and might be merged in one or two years?
This is what we done for the Mali. The devicetree binding was first done for the
out-of-tree driver, and then lima/panfrost reused it.
The key thing here is to have enough confidence about how the hardware works so
that you can accurately describe it.
Maxime
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next prev parent reply other threads:[~2020-04-21 11:21 UTC|newest]
Thread overview: 68+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-04-15 8:35 [PATCH v6 00/12] ARM/MIPS: DTS: add child nodes describing the PVRSGX GPU present in some OMAP SoC and JZ4780 (and many more) H. Nikolaus Schaller
2020-04-15 8:35 ` [PATCH v6 01/12] dt-bindings: add img,pvrsgx.yaml for Imagination GPUs H. Nikolaus Schaller
2020-04-15 10:12 ` Maxime Ripard
2020-04-15 12:43 ` H. Nikolaus Schaller
2020-04-15 12:54 ` [PATCH v6 01/12] dt-bindings: add img, pvrsgx.yaml " Neil Armstrong
2020-04-15 13:17 ` H. Nikolaus Schaller
2020-04-15 14:21 ` Maxime Ripard
2020-04-15 15:09 ` H. Nikolaus Schaller
2020-04-15 16:21 ` Maxime Ripard
2020-04-15 16:42 ` H. Nikolaus Schaller
2020-04-15 17:13 ` Tony Lindgren
2020-04-17 10:25 ` Maxime Ripard
2020-04-17 12:15 ` H. Nikolaus Schaller
2020-04-18 23:02 ` Philipp Rossak
2020-04-20 8:04 ` Maxime Ripard
2020-04-16 20:41 ` [PATCH v6 01/12] dt-bindings: add img,pvrsgx.yaml " Rob Herring
[not found] ` <C7C58E41-99CB-49F6-934E-68FA458CB8B1@goldelico.com>
2020-04-21 19:02 ` [PATCH v6 01/12] dt-bindings: add img, pvrsgx.yaml " Rob Herring
2020-04-15 8:35 ` [PATCH v6 02/12] ARM: DTS: am33xx: add sgx gpu child node H. Nikolaus Schaller
2020-04-15 8:35 ` [PATCH v6 03/12] ARM: DTS: am3517: " H. Nikolaus Schaller
2020-04-15 8:35 ` [PATCH v6 04/12] ARM: DTS: omap34xx: " H. Nikolaus Schaller
2020-04-15 8:35 ` [PATCH v6 05/12] ARM: DTS: omap36xx: " H. Nikolaus Schaller
2020-04-15 8:35 ` [PATCH v6 06/12] ARM: DTS: omap4: " H. Nikolaus Schaller
2020-04-15 8:35 ` [PATCH v6 07/12] ARM: DTS: omap5: " H. Nikolaus Schaller
2020-04-15 11:38 ` Krzysztof Kozlowski
2020-04-15 11:46 ` H. Nikolaus Schaller
2020-04-15 13:47 ` Krzysztof Kozlowski
2020-04-15 14:07 ` H. Nikolaus Schaller
2020-04-15 8:35 ` [PATCH v6 08/12] arm: dts: s5pv210: Add G3D node H. Nikolaus Schaller
2020-04-15 9:15 ` Sergei Shtylyov
2020-04-15 9:26 ` H. Nikolaus Schaller
2020-04-15 11:49 ` Krzysztof Kozlowski
2020-04-15 12:50 ` H. Nikolaus Schaller
2020-04-15 13:44 ` Krzysztof Kozlowski
2020-04-15 18:17 ` Jonathan Bakker
2020-04-16 8:50 ` Krzysztof Kozlowski
2020-04-17 12:15 ` H. Nikolaus Schaller
2020-04-22 5:56 ` kbuild test robot
2020-04-15 8:35 ` [PATCH v6 09/12] ARM: dts: sun6i: a31: add sgx gpu child node H. Nikolaus Schaller
2020-04-15 8:35 ` [PATCH v6 10/12] ARM: dts: sun6i: a31s: " H. Nikolaus Schaller
2020-04-15 8:35 ` [PATCH v6 11/12] ARM: dts: sun8i: a83t: " H. Nikolaus Schaller
2020-04-15 8:35 ` [PATCH v6 12/12] MIPS: DTS: jz4780: add sgx gpu node H. Nikolaus Schaller
2020-04-15 10:10 ` [PATCH v6 00/12] ARM/MIPS: DTS: add child nodes describing the PVRSGX GPU present in some OMAP SoC and JZ4780 (and many more) Maxime Ripard
2020-04-15 12:41 ` H. Nikolaus Schaller
2020-04-15 12:46 ` Daniel Vetter
2020-04-15 13:02 ` Maxime Ripard
2020-04-15 13:04 ` H. Nikolaus Schaller
2020-04-17 12:09 ` Philipp Rossak
2020-04-20 7:38 ` Maxime Ripard
2020-04-21 9:57 ` Philipp Rossak
2020-04-21 11:21 ` Maxime Ripard [this message]
2020-04-21 14:15 ` Tony Lindgren
2020-04-21 17:29 ` H. Nikolaus Schaller
2020-04-21 17:39 ` Tony Lindgren
2020-04-21 17:46 ` Tony Lindgren
2020-04-22 6:58 ` Maxime Ripard
2020-04-22 7:10 ` H. Nikolaus Schaller
2020-04-22 15:13 ` Maxime Ripard
2020-04-22 16:09 ` H. Nikolaus Schaller
[not found] ` <MC879Q.XY9S0U9R35681@crapouillou.net>
2020-04-22 17:23 ` H. Nikolaus Schaller
2020-04-22 19:00 ` Philipp Rossak
2020-04-22 19:33 ` Tony Lindgren
2020-04-22 21:12 ` H. Nikolaus Schaller
2020-04-23 15:00 ` Neil Armstrong
2020-04-23 15:45 ` H. Nikolaus Schaller
2020-04-23 20:36 ` Maxime Ripard
2020-04-24 9:51 ` H. Nikolaus Schaller
2020-04-21 16:42 ` Philipp Rossak
2020-04-23 20:37 ` Maxime Ripard
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