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Date: Thu, 23 Jul 2015 14:07:59 +0200
From: Pavel Machek <pavel@ucw.cz>
To: Sascha Hauer <s.hauer@pengutronix.de>
Cc: linux-pm@vger.kernel.org, Zhang Rui <rui.zhang@intel.com>,
        Eduardo Valentin <edubezval@gmail.com>, linux-kernel@vger.kernel.org,
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        linux-samsung-soc@vger.kernel.org, Guenter Roeck <linux@roeck-us.net>,
        "Rafael J. Wysocki" <rjw@rjwysocki.net>,
        Maxime Ripard <maxime.ripard@free-electrons.com>,
        Darren Hart <dvhart@infradead.org>, lm-sensors@lm-sensors.org
Subject: Re: [PATCH v2] thermal: consistently use int for temperatures
Message-ID: <20150723120759.GA17690@amd>
References: <1437463292-24844-1-git-send-email-s.hauer@pengutronix.de>
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On Tue 2015-07-21 09:21:32, Sascha Hauer wrote:
> The thermal code uses int, long and unsigned long for temperatures
> in different places.
> 
> Using an unsigned type limits the thermal framework to positive
> temperatures without need. Also several drivers currently will report
> temperatures near UINT_MAX for temperatures below 0°C. This will probably
> immediately shut the machine down due to overtemperature if started below
> 0°C.
> 
> 'long' is 64bit on several architectures. This is not needed since INT_MAX °mC
> is above the melting point of all known materials.

Can we do something like

typedef millicelsius_t int;

...to document the units?

> Consistently use a plain 'int' for temperatures throughout the thermal code and
> the drivers. This only changes the places in the drivers where the temperature
> is passed around as pointer, when drivers internally use another type this is
> not changed.

									Pavel

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