From mboxrd@z Thu Jan 1 00:00:00 1970 From: Pavel Machek Subject: Re: [PATCH v8 5/8] Loongson: YeeLoong: add hardware monitoring driver Date: Mon, 7 Dec 2009 10:49:10 +0100 Message-ID: <20091207094909.GD23088@elf.ucw.cz> References: <20091206084717.GD2766@ucw.cz> <1260147298.3126.2.camel@falcon.domain.org> <20091207080446.GB23088@elf.ucw.cz> <1260178870.9092.34.camel@falcon.domain.org> Mime-Version: 1.0 Return-path: Content-Disposition: inline In-Reply-To: <1260178870.9092.34.camel@falcon.domain.org> Sender: linux-laptop-owner@vger.kernel.org List-ID: Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit To: Wu Zhangjin Cc: Ralf Baechle , akpm@linux-foundation.org, linux-mips@linux-mips.org, linux-kernel@vger.kernel.org, Dmitry Torokhov , "Rafael J . Wysocki" , zhangfx@lemote.com, linux-laptop@vger.kernel.org, Stephen Rothwell On Mon 2009-12-07 17:41:10, Wu Zhangjin wrote: > On Mon, 2009-12-07 at 09:04 +0100, Pavel Machek wrote: > > > > 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... > > You are totally right ;) > > Just test it, when flowing from the battery, the value is negative, and > when flowing into the battery, the value is positive, so, no abs() > needed. thanks! Make it return -value, then. I believe other code uses >0 values for discharge. Pavel -- (english) http://www.livejournal.com/~pavelmachek (cesky, pictures) http://atrey.karlin.mff.cuni.cz/~pavel/picture/horses/blog.html