Re: [PATCH 03/15] dt-bindings: clock: qcom,dispcc-sm6125: Require GCC PLL0 DIV clock

From: Marijn Suijten
Date: Tue Jun 27 2023 - 05:02:42 EST


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