Re: [PATCH] drm: remove NULL pointer check for clk_disable_unprepare

[Rob Clark]

On Sat, May 20, 2017 at 3:04 PM, Masahiro Yamada
<yamada.masahiro@xxxxxxxxxxxxx> wrote:
> 2017-05-21 2:58 GMT+09:00 Masahiro Yamada <yamada.masahiro@xxxxxxxxxxxxx>:
>> After long term efforts of fixing non-common clock implementations,
>> clk_disable() is a no-op for a NULL pointer input, and this is now
>> tree-wide consistent.
>>
>> All clock consumers can safely call clk_disable(_unprepare) without
>> NULL pointer check.
>>
>> Signed-off-by: Masahiro Yamada <yamada.masahiro@xxxxxxxxxxxxx>
>
>
> Sorry, I retract this patch.
>
> Krzysztof pointed out
> cleanups only for clk_disable_unprepare() will lose the code symmetry.
>
> NULL pointer checks for clk_prepare_enable() should be
> removed to keep the code symmetrical.
>
> This is possible for common-clock framework because
> clk_prepare_enable() is also a no-op for a NULL clk input.
> But it is not necessarily true for non-common clock implementations.

At least for drm/msm, upstream I think we can assume CCF.. I still
need to check for possible downstream kernels to which someone might
want to backport drm/msm.

It might be an idea to split this up per-driver, since at least for
some drivers it might be safe to assume CCF (or non-CCF clk driver
that behaves the same)

BR,
-R

>
> --
> Best Regards
> Masahiro Yamada