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

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Date:	Mon, 08 Jun 2015 18:14:59 +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,

> 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.

-- 
Best regards,

Lukasz Majewski

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