From: Stephen Boyd <sboyd@kernel.org>
To: Matthias Brugger <matthias.bgg@gmail.com>,
Matthias Brugger <mbrugger@suse.com>,
Rob Herring <robh@kernel.org>
Cc: matthias.bgg@kernel.org, Mark Rutland <mark.rutland@arm.com>,
CK Hu <ck.hu@mediatek.com>,
Philipp Zabel <p.zabel@pengutronix.de>,
David Airlie <airlied@linux.ie>,
Michael Turquette <mturquette@baylibre.com>,
Stephen Boyd <sboyd@codeaurora.org>,
Ulrich Hecht <ulrich.hecht+renesas@gmail.com>,
Laurent Pinchart <laurent.pinchart@ideasonboard.com>,
Sean Wang <sean.wang@mediatek.com>,
Sean Wang <sean.wang@kernel.org>,
Randy Dunlap <rdunlap@infradead.org>,
Chen-Yu Tsai <wens@csie.org>,
dri-devel <dri-devel@lists.freedesktop.org>,
"linux-kernel@vger.kernel.org" <linux-kernel@vger.kernel.org>,
"moderated list:ARM/FREESCALE IMX / MXC ARM ARCHITECTURE"
<linux-arm-kernel@lists.infradead.org>,
linux-mediatek@lists.infradead.org,
linux-clk <linux-clk@vger.kernel.org>,
devicetree@vger.kernel.org
Subject: Re: [PATCH v5 08/12] dt-bindings: mediatek: Change the binding for mmsys clocks
Date: Thu, 29 Nov 2018 22:43:57 -0800 [thread overview]
Message-ID: <154356023767.88331.18401188808548429052@swboyd.mtv.corp.google.com> (raw)
In-Reply-To: <458178ac-c0fc-9671-7fc8-ed2d6f61424c@suse.com>
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!
>
> 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.
>
> 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.
next prev parent reply other threads:[~2018-11-30 6:44 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 [this message]
2018-11-30 8:59 ` Matthias Brugger
2019-07-01 3:55 ` CK Hu
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
Reply instructions:
You may reply publicly to this message via plain-text email
using any one of the following methods:
* Save the following mbox file, import it into your mail client,
and reply-to-all from there: mbox
Avoid top-posting and favor interleaved quoting:
https://en.wikipedia.org/wiki/Posting_style#Interleaved_style
* Reply using the --to, --cc, and --in-reply-to
switches of git-send-email(1):
git send-email \
--in-reply-to=154356023767.88331.18401188808548429052@swboyd.mtv.corp.google.com \
--to=sboyd@kernel.org \
--cc=airlied@linux.ie \
--cc=ck.hu@mediatek.com \
--cc=devicetree@vger.kernel.org \
--cc=dri-devel@lists.freedesktop.org \
--cc=laurent.pinchart@ideasonboard.com \
--cc=linux-arm-kernel@lists.infradead.org \
--cc=linux-clk@vger.kernel.org \
--cc=linux-kernel@vger.kernel.org \
--cc=linux-mediatek@lists.infradead.org \
--cc=mark.rutland@arm.com \
--cc=matthias.bgg@gmail.com \
--cc=matthias.bgg@kernel.org \
--cc=mbrugger@suse.com \
--cc=mturquette@baylibre.com \
--cc=p.zabel@pengutronix.de \
--cc=rdunlap@infradead.org \
--cc=robh@kernel.org \
--cc=sboyd@codeaurora.org \
--cc=sean.wang@kernel.org \
--cc=sean.wang@mediatek.com \
--cc=ulrich.hecht+renesas@gmail.com \
--cc=wens@csie.org \
/path/to/YOUR_REPLY
https://kernel.org/pub/software/scm/git/docs/git-send-email.html
* If your mail client supports setting the In-Reply-To header
via mailto: links, try the mailto: link
Be sure your reply has a Subject: header at the top and a blank line
before the message body.
This is a public inbox, see mirroring instructions
for how to clone and mirror all data and code used for this inbox;
as well as URLs for NNTP newsgroup(s).