Re: [PATCH v4 00/15] clk: qcom: Fix parenting for dispcc/gpucc/videocc

From: Doug Anderson <dianders@chromium.org>
To: Bjorn Andersson <bjorn.andersson@linaro.org>
Cc: Stephen Boyd <sboyd@kernel.org>, Andy Gross <agross@kernel.org>,
	Rob Herring <robh@kernel.org>,
	Jeffrey Hugo <jhugo@codeaurora.org>,
	Taniya Das <tdas@codeaurora.org>,
	Jeffrey Hugo <jeffrey.l.hugo@gmail.com>,
	linux-arm-msm <linux-arm-msm@vger.kernel.org>,
	Harigovindan P <harigovi@codeaurora.org>,
	"open list:OPEN FIRMWARE AND FLATTENED DEVICE TREE BINDINGS" 
	<devicetree@vger.kernel.org>,
	Matthias Kaehlcke <mka@chromium.org>,
	Kalyan Thota <kalyan_t@codeaurora.org>,
	Mark Rutland <mark.rutland@arm.com>,
	linux-clk <linux-clk@vger.kernel.org>,
	"Kristian H. Kristensen" <hoegsberg@chromium.org>,
	Michael Turquette <mturquette@baylibre.com>,
	LKML <linux-kernel@vger.kernel.org>,
	Rob Herring <robh+dt@kernel.org>
Subject: Re: [PATCH v4 00/15] clk: qcom: Fix parenting for dispcc/gpucc/videocc
Date: Mon, 3 Feb 2020 12:48:39 -0800	[thread overview]
Message-ID: <CAD=FV=VQyTHYizfzMwjAaRbmQ4zvFFzdfgGiVkLQU+b+pFVnzg@mail.gmail.com> (raw)
In-Reply-To: <20200203200443.GN3948@builder>

Hi,

On Mon, Feb 3, 2020 at 12:04 PM Bjorn Andersson
<bjorn.andersson@linaro.org> wrote:
>
> On Mon 03 Feb 11:41 PST 2020, Doug Anderson wrote:
>
> > Hi,
> >
> > On Mon, Feb 3, 2020 at 11:30 AM Stephen Boyd <sboyd@kernel.org> wrote:
> > >
> > > Quoting Douglas Anderson (2020-02-03 10:31:33)
> > > >
> > > >  .../devicetree/bindings/clock/qcom,gpucc.yaml | 72 --------------
> > > >  ...om,dispcc.yaml => qcom,msm8998-gpucc.yaml} | 33 +++----
> > > >  .../bindings/clock/qcom,sc7180-dispcc.yaml    | 84 ++++++++++++++++
> > > >  .../bindings/clock/qcom,sc7180-gpucc.yaml     | 72 ++++++++++++++
> > > >  .../bindings/clock/qcom,sc7180-videocc.yaml   | 63 ++++++++++++
> > > >  .../bindings/clock/qcom,sdm845-dispcc.yaml    | 99 +++++++++++++++++++
> > > >  .../bindings/clock/qcom,sdm845-gpucc.yaml     | 72 ++++++++++++++
> > > >  ...,videocc.yaml => qcom,sdm845-videocc.yaml} | 27 ++---
> > > >  arch/arm64/boot/dts/qcom/sc7180.dtsi          | 47 +++++++++
> > > >  arch/arm64/boot/dts/qcom/sdm845.dtsi          | 28 +++++-
> > >
> > > I don't want to take patches touching dts/qcom/. These aren't necessary
> > > to merge right now, correct? Or at least, they can go via arm-soc tree?
> >
> > Right.  They can go later.
> >
> > Specifically for sdm845 until the sdm845 patches lands the old dts
> > trees will yell about the missing clocks, but it's not like they will
> > compile fail.  Also the bindings themselves will validate fine.
> > There's no other way forward, though, and the old bindings caused
> > similar yells.
> >
>
> Can you please help me parse this, will old DT cause complaints or will
> it fail to boot?

Sorry, let me try to be more clear:

a) Without my series: "make dtbs_check" limited to the bindings files
I'm touching yells.  Examples:

.../msm8998-mtp.dt.yaml: clock-controller@5065000: clock-names:1:
'gpll0_main' was expected

.../sdm845-mtp.dt.yaml: clock-controller@af00000: 'clocks' is a
required property
.../sdm845-mtp.dt.yaml: clock-controller@af00000: 'clock-names' is a
required property

.../sdm845-mtp.dt.yaml: clock-controller@ab00000: 'clocks' is a
required property
.../sdm845-mtp.dt.yaml: clock-controller@ab00000: 'clock-names' is a
required property

b) With just the bindings from my series, "make dtbs_check" yells, but
yells about different things.  The "gpll0_main" one goes away but this
one is new:

.../sdm845-mtp.dt.yaml: clock-controller@5090000: clock-names:0:
'bi_tcxo' was expected
.../sdm845-mtp.dt.yaml: clock-controller@5090000: clock-names: ['xo']
is too short
.../sdm845-mtp.dt.yaml: clock-controller@5090000: clocks: [[26, 0]] is too short

c) With just the "dts" from my series, you'll again get different
yells from "make dtbs_check".  I won't bother listing them, but they
are similar to the above.

d) With everything from my series, the "make dtbs_check" limited to
the bindings files I'm touching is clean.

---

* sdm845's ability to boot is unaffected by this series.  I have
tested booting sdm845 after this series and it's fine.  Since nothing
in this series touches the sdm845 clock drivers (only the bindings and
the dts) that means that the new dts must work with the existing
drivers.  You can land the sdm845 dts any time after Stephen and Rob
are happy with the bindings.

* It should be fine to land the sc7180 dts file without waiting for
the driver change.  The dts here will work with both the
dispcc/gpucc/videocc that's in clk-next and also the one that results
from applying all of my patches.

> > For sc7180 there's no usage of any of these clocks and this adds the
> > first usage, so definitely no problem there.
> >
> > Once you've landed then Bjorn or Andy can pick up the dts.
> >
>
> Do I need to apply these after Stephen picks the driver patches? Or are
> they simply nop until the driver patches lands?

The sdm845 patches are a nop until some future patch changes the Linux
driver to start using them.  I don't know of anyone planning to do
that.  The only real result from an sdm845 perspective will be making
things "more correct" from a dts standpoint and keeping "make
dtbs_check" happier.

The sc7180 patches are OK to land even without the driver.  They're
not a nop and I've actually validated that I can bring the display/gpu
up with them (even without the driver changes) on my downstream
kernel.

---

Sorry it's so confusing.  Happy to try to clarify more if the above is
still too hard to follow.

-Doug