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Re: [PATCH v8 5/8] Loongson: YeeLoong: add hardware monitoring driver

To: Wu Zhangjin <wuzhangjin@gmail.com>
Subject: Re: [PATCH v8 5/8] Loongson: YeeLoong: add hardware monitoring driver
From: Pavel Machek <pavel@ucw.cz>
Date: Mon, 7 Dec 2009 09:04:46 +0100
Cc: Ralf Baechle <ralf@linux-mips.org>, akpm@linux-foundation.org, linux-mips@linux-mips.org, linux-kernel@vger.kernel.org, Dmitry Torokhov <dmitry.torokhov@gmail.com>, "Rafael J . Wysocki" <rjw@sisk.pl>, zhangfx@lemote.com, linux-laptop@vger.kernel.org, Stephen Rothwell <sfr@canb.auug.org.au>
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> > What is going on here? I thought the value is already in two's
> > complement... Is the above equivalent of
> > 
> >           if (value < 0)
> >              value = -value; 
> > 
> > ? If so, why? If not, can you add a comment?
> 
> Right, then, will use this instead:
> 
> static int get_battery_current(void)
> { 
>       s16 value;
> 
>       value = (ec_read(REG_BAT_CURRENT_HIGH) << 8) |
>               (ec_read(REG_BAT_CURRENT_LOW));
> 
>       return abs(value);
> }

That's certainly better. But... why not return signed value? Current
flowing from the battery is certainly very different from current
flowing into it...
                                                                        Pavel
-- 
(english) http://www.livejournal.com/~pavelmachek
(cesky, pictures) 
http://atrey.karlin.mff.cuni.cz/~pavel/picture/horses/blog.html

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