linux-kernel - Re: [PATCH] thermal: exynos: Disable the regulator on probe failure

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Message-id: <20150706090133.71b4be9b@amdc2363>
Date:	Mon, 06 Jul 2015 09:01:33 +0200
From:	Lukasz Majewski <l.majewski@...sung.com>
To:	Krzysztof Kozlowski <k.kozlowski@...sung.com>
Cc:	Zhang Rui <rui.zhang@...el.com>,
	Eduardo Valentin <edubezval@...il.com>,
	Kukjin Kim <kgene@...nel.org>, linux-pm@...r.kernel.org,
	linux-samsung-soc@...r.kernel.org,
	linux-arm-kernel@...ts.infradead.org, linux-kernel@...r.kernel.org,
	stable@...r.kernel.org
Subject: Re: [PATCH] thermal: exynos: Disable the regulator on probe failure

Hi Krzysztof,

> 2015-06-09 1:14 GMT+09:00 Lukasz Majewski <l.majewski@...sung.com>:
> > Hi Krzysztof,
> >
> >> During probe the regulator (if present) was enabled but not
> >> disabled in case of failure. So an unsuccessful probe lead to
> >> enabling the regulator which was actually not needed because the
> >> device was not enabled.
> >>
> >> Additionally each deferred probe lead to increase of regulator
> >> enable count so it would not be effectively disabled during
> >> removal of the device.
> >
> > Thanks for catching this.
> >
> >>
> >> Signed-off-by: Krzysztof Kozlowski <k.kozlowski@...sung.com>
> >> Fixes: 498d22f616f6 ("thermal: exynos: Support for TMU regulator
> >> defined at device tree") Cc: <stable@...r.kernel.org>
> >>
> >> ---
> >>
> >> I am not entirely convinced that this should go to stable. Leaving
> >> a regulator enabled in case of probe failure (no exynos TMU
> >> device) or after deferred probe (regulator won't be disabled
> >> during device removal) is not a critical issue, just leaks power.
> >> ---
> >>  drivers/thermal/samsung/exynos_tmu.c | 2 ++
> >>  1 file changed, 2 insertions(+)
> >>
> >> diff --git a/drivers/thermal/samsung/exynos_tmu.c
> >> b/drivers/thermal/samsung/exynos_tmu.c index
> >> 531f4b179871..13c3aceed19d 100644 ---
> >> a/drivers/thermal/samsung/exynos_tmu.c +++
> >> b/drivers/thermal/samsung/exynos_tmu.c @@ -1392,6 +1392,8 @@
> >> err_clk_sec: if (!IS_ERR(data->clk_sec))
> >>               clk_unprepare(data->clk_sec);
> >>  err_sensor:
> >> +     if (!IS_ERR_OR_NULL(data->regulator))
> >> +             regulator_disable(data->regulator);
> >>       thermal_zone_of_sensor_unregister(&pdev->dev, data->tzd);
> >>
> >>       return ret;
> >
> > Acked-by: Lukasz Majewski <l.majewski@...sung.com>
> >
> > I will test it and afterwards add to samsung-thermal tree.
> 
> Hi Łukasz,
> 
> I can't find this patch in v4.2-rc1 or your tree. What happened?

I will got together with Chanowoo patches. I will send PR today to
Eduardo.

> 
> Best regards,
> Krzysztof



-- 
Best regards,

Lukasz Majewski

Samsung R&D Institute Poland (SRPOL) | Linux Platform Group
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