linux-kernel - Re: [PATCHv2 3/6] thermal: exynos: Check before clk_disable

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Date:   Wed, 18 May 2022 00:14:16 +0530
From:   Anand Moon <linux.amoon@...il.com>
To:     Krzysztof Kozlowski <krzysztof.kozlowski@...aro.org>
Cc:     Bartlomiej Zolnierkiewicz <bzolnier@...il.com>,
        "Rafael J. Wysocki" <rafael@...nel.org>,
        Daniel Lezcano <daniel.lezcano@...aro.org>,
        Amit Kucheria <amitk@...nel.org>,
        Zhang Rui <rui.zhang@...el.com>,
        Alim Akhtar <alim.akhtar@...sung.com>,
        Linux PM list <linux-pm@...r.kernel.org>,
        linux-samsung-soc@...r.kernel.org,
        linux-arm-kernel <linux-arm-kernel@...ts.infradead.org>,
        Linux Kernel <linux-kernel@...r.kernel.org>
Subject: Re: [PATCHv2 3/6] thermal: exynos: Check before clk_disable_unprepare()
 not needed

Hi Krzysztof,

On Sun, 15 May 2022 at 15:13, Krzysztof Kozlowski
<krzysztof.kozlowski@...aro.org> wrote:
>
> On 15/05/2022 08:41, Anand Moon wrote:
> > All code in clk_disable_unprepare() already checks the clk ptr using
> > IS_ERR_OR_NULL so there is no need to check it again before calling it.
> > A lot of other drivers already rely on this behaviour, so it's safe
> > to do so here.
> >
> > Cc: Bartlomiej Zolnierkiewicz <bzolnier@...il.com>
> > Signed-off-by: Anand Moon <linux.amoon@...il.com>
> > ---
> > v1: improve the commit message
> > ---
> >  drivers/thermal/samsung/exynos_tmu.c | 12 ++++--------
> >  1 file changed, 4 insertions(+), 8 deletions(-)
> >
> > diff --git a/drivers/thermal/samsung/exynos_tmu.c b/drivers/thermal/samsung/exynos_tmu.c
> > index 1ef90dc52c08..58ff1b577c47 100644
> > --- a/drivers/thermal/samsung/exynos_tmu.c
> > +++ b/drivers/thermal/samsung/exynos_tmu.c
> > @@ -289,8 +289,7 @@ static int exynos_tmu_initialize(struct platform_device *pdev)
> >
> >       mutex_lock(&data->lock);
> >       clk_enable(data->clk);
> > -     if (!IS_ERR(data->clk_sec))
> > -             clk_enable(data->clk_sec);
> > +     clk_enable(data->clk_sec);
>
> You say that clk_enable() checks for IS_ERR_OR_NULL. Where? I see only
> check for non-null case and then immediately taking clk prepare lock.
>
> This looks buggy... did you test it?

Thanks for your review comments
Yes have tested the changes, this was last-minute changes
will drop this in the next version.

>
> Best regards,
> Krzysztof

Thanks & Regards


-Anand