Re: [PATCH v7 7/8] clk: qcom: dispcc-sm8250: stop using mmcx regulator

From: Stephen Boyd <sboyd@kernel.org>
To: Bjorn Andersson <bjorn.andersson@linaro.org>
Cc: Dmitry Baryshkov <dmitry.baryshkov@linaro.org>,
	Andy Gross <agross@kernel.org>, Rob Herring <robh+dt@kernel.org>,
	Taniya Das <tdas@codeaurora.org>,
	Jonathan Marek <jonathan@marek.ca>,
	Michael Turquette <mturquette@baylibre.com>,
	DRM DRIVER FOR MSM ADRENO GPU  <linux-arm-msm@vger.kernel.org>,
	OPEN FIRMWARE AND FLATTENED DEVICE TREE BINDINGS 
	<devicetree@vger.kernel.org>,
	COMMON CLK FRAMEWORK <linux-clk@vger.kernel.org>,
	Bryan O'Donoghue <bryan.odonoghue@linaro.org>,
	Mark Brown <broonie@kernel.org>,
	Ulf Hansson <ulf.hansson@linaro.org>,
	open list <linux-kernel@vger.kernel.org>
Subject: Re: [PATCH v7 7/8] clk: qcom: dispcc-sm8250: stop using mmcx regulator
Date: Thu, 14 Oct 2021 17:49:40 -0700	[thread overview]
Message-ID: <163425898010.1688384.4973790117705709295@swboyd.mtv.corp.google.com> (raw)
In-Reply-To: <YWjPexTTQYyZ9JNM@ripper>

Quoting Bjorn Andersson (2021-10-14 17:46:51)
> On Thu 14 Oct 17:25 PDT 2021, Stephen Boyd wrote:
> 
> > Quoting Dmitry Baryshkov (2021-10-14 17:15:39)
> > > On Fri, 15 Oct 2021 at 03:04, Stephen Boyd <sboyd@kernel.org> wrote:
> > > >
> > > > Quoting Dmitry Baryshkov (2021-10-14 02:53:41)
> > > > > On 13/10/2021 22:50, Stephen Boyd wrote:
> > > > > > Quoting Dmitry Baryshkov (2021-10-07 09:16:13)
> > > > > >> On 07/10/2021 18:48, Bjorn Andersson wrote:
> > > > > >>> On Sun 29 Aug 08:47 PDT 2021, Dmitry Baryshkov wrote:
> > > > > >>>
> > > > > >>>> Now as the common qcom clock controller code has been taught about power
> > > > > >>>> domains, stop mentioning mmcx supply as a way to power up the clock
> > > > > >>>> controller's gdsc.
> > > > > >>>>
> > > > > >>>> Signed-off-by: Dmitry Baryshkov <dmitry.baryshkov@linaro.org>
> > > > > >>>> Reviewed-by: Bjorn Andersson <bjorn.andersson@linaro.org>
> > > > > >>>
> > > > > >>> Once we merge these, I expect that the boards will start crashing if
> > > > > >>> the kernel is booted using an existing DTB?
> > > > > >>>
> > > > > >>> Is it okay to just merge the first 6 patches in the series now and
> > > > > >>> postpone these two until we've had the dts change sitting for a while?
> > > > > >>
> > > > > >> Sure it is.
> > > > > >>
> > > > > >
> > > > > > What's the merge strategy? It goes through arm-soc?
> > > > >
> > > > > I think this should go through the clk tree. There is little chance of
> > > > > conflicts.
> > > > >
> > > >
> > > > The other thing that concerns me is that we don't have backwards
> > > > compat code. If things are going to start crashing that's not very nice.
> > > > Is there some way to make it work with old and new DTB for one release
> > > > so that we don't have to worry about this problem?
> > > 
> > > I have to admit that I did not check that, but without the patch 7 the
> > > dispcc and videocc would be compatible with the old DTB. The 'supply =
> > > "mmcx"' would ensure that it is used if it is defined.
> > > 
> > 
> > So I can skip patch 7 and take everything else?
> 
> If you take patch 1-5 and I pick up patch 6 for v5.16 then we should
> have transitioned with backwards compatibility.
> 

Ok. Sounds like a deal.