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Date:   Tue, 27 Jun 2023 11:02:27 +0200
From:   Marijn Suijten <marijn.suijten@somainline.org>
To:     Krzysztof Kozlowski <krzysztof.kozlowski@linaro.org>
Cc:     Konrad Dybcio <konrad.dybcio@linaro.org>,
        Andy Gross <agross@kernel.org>,
        Bjorn Andersson <andersson@kernel.org>,
        Rob Herring <robh+dt@kernel.org>,
        Krzysztof Kozlowski <krzysztof.kozlowski+dt@linaro.org>,
        Conor Dooley <conor+dt@kernel.org>,
        Michael Turquette <mturquette@baylibre.com>,
        Stephen Boyd <sboyd@kernel.org>,
        Rob Clark <robdclark@gmail.com>,
        Abhinav Kumar <quic_abhinavk@quicinc.com>,
        Dmitry Baryshkov <dmitry.baryshkov@linaro.org>,
        Sean Paul <sean@poorly.run>, David Airlie <airlied@gmail.com>,
        Daniel Vetter <daniel@ffwll.ch>,
        Krishna Manikandan <quic_mkrishn@quicinc.com>,
        ~postmarketos/upstreaming@lists.sr.ht,
        AngeloGioacchino Del Regno 
        <angelogioacchino.delregno@collabora.com>,
        Martin Botka <martin.botka@somainline.org>,
        Jami Kettunen <jami.kettunen@somainline.org>,
        linux-arm-msm@vger.kernel.org, devicetree@vger.kernel.org,
        linux-kernel@vger.kernel.org,
        Krzysztof Kozlowski <krzk@kernel.org>,
        linux-clk@vger.kernel.org, dri-devel@lists.freedesktop.org,
        freedreno@lists.freedesktop.org, Lux Aliaga <they@mint.lgbt>
Subject: Re: [PATCH 03/15] dt-bindings: clock: qcom,dispcc-sm6125: Require
 GCC PLL0 DIV clock
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On 2023-06-27 10:21:12, Krzysztof Kozlowski wrote:
> On 27/06/2023 09:49, Marijn Suijten wrote:
> > On 2023-06-27 09:29:53, Krzysztof Kozlowski wrote:
> >> On 27/06/2023 08:54, Marijn Suijten wrote:
> >>> On 2023-06-27 08:24:41, Krzysztof Kozlowski wrote:
> >>>> On 26/06/2023 20:53, Marijn Suijten wrote:
> >>>>> On 2023-06-26 20:51:38, Marijn Suijten wrote:
> >>>>> <snip>
> >>>>>>> Not really, binding also defines the list of clocks - their order and
> >>>>>>> specific entries. This changes.
> >>>>>>
> >>>>>> And so it does in "dt-bindings: clock: qcom,dispcc-sm6125: Remove unused
> >>>>>> GCC_DISP_AHB_CLK"?
> >>>>>
> >>>>> Never mind: it is the last item so the order of the other items doesn't
> >>>>> change.  The total number of items decreases though, which sounds like
> >>>>> an ABI-break too?
> >>>>
> >>>> How does it break? Old DTS works exactly the same, doesn't it?
> >>>
> >>> So deleting a new item at the end does not matter.  But what if I respin
> >>> this patch to add the new clock _at the end_, which will then be at the
> >>> same index as the previous GCC_DISP_AHB_CLK?
> >>
> >> I think you know the answer, right? What do you want to prove? That two
> >> independent changes can have together negative effect? We know this.
> > 
> > The question is whether this is allowed?
> 
> That would be an ABI break and I already explained if it is or is not
> allowed.

How should we solve it then, if we cannot remove GCC_DISP_AHB_CLK in one
patch and add GCC_DISP_GPLL0_DIV_CLK_SRC **at the end** in the next
patch?  Keep an empty spot at the original index of GCC_DISP_AHB_CLK?

- Marijn