linux-kernel - Re: [PATCH] drm: remove NULL pointer check for clk_disable

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Message-ID: <CAK7LNAQCF1UATHONzLnrUN=uvVw6tsErfbDS9joFo3ya5Vgy4A@mail.gmail.com>
Date:   Sun, 21 May 2017 04:04:22 +0900
From:   Masahiro Yamada <yamada.masahiro@...ionext.com>
To:     Daniel Vetter <daniel.vetter@...el.com>,
        dri-devel <dri-devel@...ts.freedesktop.org>,
        David Airlie <airlied@...ux.ie>
Cc:     Masahiro Yamada <yamada.masahiro@...ionext.com>,
        Lucas Stach <l.stach@...gutronix.de>,
        freedreno@...ts.freedesktop.org,
        Benjamin Gaignard <benjamin.gaignard@...aro.org>,
        Thierry Reding <thierry.reding@...il.com>,
        Vincent Abriou <vincent.abriou@...com>,
        Christian Gmeiner <christian.gmeiner@...il.com>,
        Jonathan Hunter <jonathanh@...dia.com>,
        linux-arm-msm <linux-arm-msm@...r.kernel.org>,
        Ben Skeggs <bskeggs@...hat.com>, etnaviv@...ts.freedesktop.org,
        Tomi Valkeinen <tomi.valkeinen@...com>,
        Linux Kernel Mailing List <linux-kernel@...r.kernel.org>,
        linux-renesas-soc@...r.kernel.org, Marek Vasut <marex@...x.de>,
        Rob Clark <robdclark@...il.com>, nouveau@...ts.freedesktop.org,
        linux-tegra@...r.kernel.org,
        Laurent Pinchart <laurent.pinchart@...asonboard.com>,
        Russell King <linux+etnaviv@...linux.org.uk>
Subject: Re: [PATCH] drm: remove NULL pointer check for clk_disable_unprepare

2017-05-21 2:58 GMT+09:00 Masahiro Yamada <yamada.masahiro@...ionext.com>:
> 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@...ionext.com>


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.


-- 
Best Regards
Masahiro Yamada