From: CK Hu <ck.hu@mediatek.com>
To: Matthias Brugger <mbrugger@suse.com>
Cc: Stephen Boyd <sboyd@kernel.org>,
Matthias Brugger <matthias.bgg@gmail.com>,
Rob Herring <robh@kernel.org>,
Mark Rutland <mark.rutland@arm.com>,
"devicetree@vger.kernel.org" <devicetree@vger.kernel.org>,
Sean Wang <sean.wang@kernel.org>,
"David Airlie" <airlied@linux.ie>,
Michael Turquette <mturquette@baylibre.com>,
Sean Wang <Sean.Wang@mediatek.com>,
Stephen Boyd <sboyd@codeaurora.org>,
"linux-kernel@vger.kernel.org" <linux-kernel@vger.kernel.org>,
dri-devel <dri-devel@lists.freedesktop.org>,
Ulrich Hecht <ulrich.hecht+renesas@gmail.com>,
Chen-Yu Tsai <wens@csie.org>,
"Randy Dunlap" <rdunlap@infradead.org>,
Laurent Pinchart <laurent.pinchart@ideasonboard.com>,
Philipp Zabel <p.zabel@pengutronix.de>,
"matthias.bgg@kernel.org" <matthias.bgg@kernel.org>,
"linux-mediatek@lists.infradead.org"
<linux-mediatek@lists.infradead.org>,
linux-clk <linux-clk@vger.kernel.org>,
"moderated list:ARM/FREESCALE IMX / MXC ARM ARCHITECTURE"
<linux-arm-kernel@lists.infradead.org>
Subject: Re: [PATCH v5 08/12] dt-bindings: mediatek: Change the binding for mmsys clocks
Date: Mon, 1 Jul 2019 11:55:18 +0800 [thread overview]
Message-ID: <1561953318.25914.9.camel@mtksdaap41> (raw)
In-Reply-To: <a229bfc7-683f-5b0d-7b71-54f934de6214@suse.com>
Hi, Matthias:
On Fri, 2018-11-30 at 16:59 +0800, Matthias Brugger wrote:
>
> On 30/11/2018 07:43, Stephen Boyd wrote:
> > Quoting Matthias Brugger (2018-11-21 09:09:52)
> >>
> >>
> >> On 21/11/2018 17:46, Stephen Boyd wrote:
> >>> Quoting Rob Herring (2018-11-19 11:15:16)
> >>>> On Sun, Nov 18, 2018 at 11:12 AM Matthias Brugger
> >>>> <matthias.bgg@gmail.com> wrote:
> >>>>> On 11/17/18 12:15 AM, Rob Herring wrote:
> >>>>>> On Fri, Nov 16, 2018 at 01:54:45PM +0100, matthias.bgg@kernel.org wrote:
> >>>>>>> - #clock-cells = <1>;
> >>>>>>> +
> >>>>>>> + mmsys_clk: clock-controller@14000000 {
> >>>>>>> + compatible = "mediatek,mt2712-mmsys-clk";
> >>>>>>> + #clock-cells = <1>;
> >>>>>>
> >>>>>> This goes against the general direction of not defining separate nodes
> >>>>>> for providers with no resources.
> >>>>>>
> >>>>>> Why do you need this and what does it buy if you have to continue to
> >>>>>> support the existing chips?
> >>>>>>
> >>>>>
> >>>>> It would show explicitly that the mmsys block is used to probe two
> >>>>> drivers, one for the gpu and one for the clocks. Otherwise that is
> >>>>> hidden in the drm driver code. I think it is cleaner to describe that in
> >>>>> the device tree.
> >>>>
> >>>> No, that's maybe cleaner for the driver implementation in the Linux
> >>>> kernel. What about other OS's or when Linux drivers and subsystems
> >>>> needs change? Cleaner for DT is design bindings that reflect the h/w.
> >>>> Hardware is sometimes just messy.
> >>>>
> >>>
> >>> I agree. I fail to see what this patch series is doing besides changing
> >>> driver probe and device creation methods and making a backwards
> >>> incompatible change to DT. Is there any other benefit here?
> >>>
> >>
> >> You are referring whole series?
> >> Citing the cover letter:
> >> "MMSYS in Mediatek SoCs has some registers to control clock gates (which is
> >> used in the clk driver) and some registers to set the routing and enable
> >> the differnet (sic!) blocks of the display subsystem.
> >>
> >> Up to now both drivers, clock and drm are probed with the same device tree
> >> compatible. But only the first driver get probed, which in effect breaks
> >> graphics on mt8173 and mt2701.
> >
> > Ouch!
> >
>
> Yes :)
>
> >>
> >> This patch uses a platform device registration in the DRM driver, which
> >> will trigger the probe of the corresponding clock driver. It was tested on the
> >> bananapi-r2 and the Acer R13 Chromebook."
> >
> > Alright, please don't add nodes in DT just to make device drivers probe.
> > Instead, register clks from the drm driver or create a child platform
> > device for the clk bits purely in the drm driver and have that probe the
> > associated clk driver from there.
> >
>
> I'll make the other SoCs probe via a child platform device from the drm driver,
> as already done in 2/12 and 3/12.
This series have been pending for half an year, would you keep going on
this series? If you're busy, I could complete this series, but I need to
know what you have plan to do.
I guess that 1/12 ~ 5/12 is for MT2701/MT8173 and that patches meet this
discussion. 6/12 ~ 12/12 is for MT2712/MT6797 but that patches does not
meet this discussion. So the unfinished work is to make MT2712/MT6797 to
align MT2701/MT8173, is this right?
Regards,
CK
>
> Regards,
> Matthias
>
> >>
> >> DT is broken right now, because two drivers rely on the same node, which gets
> >> consumed just once. The new DT introduced does not break anything because it is
> >> only used for boards that: "[..] are not available to the general public
> >> (mt2712e) or only have the mmsys clock driver part implemented (mt6797)."
> >
> > Ok, so backwards compatibility is irrelevant then. Sounds fine to me.
> >
> >
>
> _______________________________________________
> Linux-mediatek mailing list
> Linux-mediatek@lists.infradead.org
> http://lists.infradead.org/mailman/listinfo/linux-mediatek
next prev parent reply other threads:[~2019-07-01 4:00 UTC|newest]
Thread overview: 40+ messages / expand[flat|nested] mbox.gz Atom feed top
2018-11-16 12:54 [PATCH v5 00/12] arm/arm64: mediatek: Fix mmsys device probing matthias.bgg
2018-11-16 12:54 ` [PATCH v5 01/12] drm/mediatek: Use regmap for register access matthias.bgg
2018-11-16 12:54 ` [PATCH v5 02/12] clk: mediatek: mt2701-mmsys: switch to platform device probing matthias.bgg
2018-11-16 12:54 ` [PATCH v5 03/12] clk: mediatek: mt8173: switch mmsys " matthias.bgg
2019-10-31 4:17 ` Hsin-Yi Wang
2019-11-04 11:14 ` Matthias Brugger
2018-11-16 12:54 ` [PATCH v5 04/12] drm/mediatek: Add support for mmsys through a pdev matthias.bgg
2018-11-19 5:54 ` CK Hu
2018-11-16 12:54 ` [PATCH v5 05/12] drm: mediatek: Omit warning on probe defers matthias.bgg
2018-11-19 5:38 ` CK Hu
2018-11-19 9:26 ` Matthias Brugger
2018-11-20 4:05 ` CK Hu
2018-11-20 4:09 ` CK Hu
2018-11-20 8:26 ` Aw: Re: [PATCH v5 05/12] drm: mediatek Frank Wunderlich
2018-11-20 10:14 ` Matthias Brugger
2018-11-20 10:34 ` Aw: " Frank Wunderlich
2018-11-20 11:39 ` Matthias Brugger
2018-11-20 10:19 ` [PATCH v5 05/12] drm: mediatek: Omit warning on probe defers Matthias Brugger
2018-11-20 10:23 ` CK Hu
2018-11-16 12:54 ` [PATCH v5 06/12] drm/mediatek: update dt-bindings matthias.bgg
2018-11-16 23:06 ` Rob Herring
2018-11-16 12:54 ` [PATCH v5 07/12] dt-bindings: clock: mediatek: delete mmsys clocks matthias.bgg
2018-11-16 23:07 ` Rob Herring
2018-11-16 12:54 ` [PATCH v5 08/12] dt-bindings: mediatek: Change the binding for " matthias.bgg
2018-11-16 23:15 ` Rob Herring
2018-11-18 17:12 ` Matthias Brugger
2018-11-19 19:15 ` Rob Herring
2018-11-21 16:46 ` Stephen Boyd
2018-11-21 17:09 ` Matthias Brugger
2018-11-30 6:43 ` Stephen Boyd
2018-11-30 8:59 ` Matthias Brugger
2019-07-01 3:55 ` CK Hu [this message]
2019-07-04 9:08 ` Matthias Brugger
2019-07-04 15:33 ` Ulrich Hecht
2019-07-05 1:35 ` CK Hu
2019-07-05 10:13 ` Matthias Brugger
2018-11-16 12:54 ` [PATCH v5 09/12] arm64: dts: mt2712e: Use the new mmsys clock compatible matthias.bgg
2018-11-16 12:54 ` [PATCH v5 10/12] arm64: dts: mt6797: " matthias.bgg
2018-11-16 12:54 ` [PATCH v5 11/12] clk: mediatek: mt2712e: Probe with new compatible matthias.bgg
2018-11-16 12:54 ` [PATCH v5 12/12] clk: mediatek: mt6797: " matthias.bgg
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