Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1759198AbZLGJlg (ORCPT ); Mon, 7 Dec 2009 04:41:36 -0500 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1759227AbZLGJlf (ORCPT ); Mon, 7 Dec 2009 04:41:35 -0500 Received: from mail-pw0-f42.google.com ([209.85.160.42]:59464 "EHLO mail-pw0-f42.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1759180AbZLGJld (ORCPT ); Mon, 7 Dec 2009 04:41:33 -0500 DomainKey-Signature: a=rsa-sha1; c=nofws; d=gmail.com; s=gamma; h=subject:from:reply-to:to:cc:in-reply-to:references:content-type :organization:date:message-id:mime-version:x-mailer :content-transfer-encoding; b=H6FQwCvgvdQVIp3vxc3nqFCFO98BG1sYujLquQqpLeCoQUn/+MaIIj6nQN14dlY6nf iIPn1kGE6Pe4trvKp87bfGrzM/2wyifvOorxRsItmms097aiKuzE+z3Ih30YgFOg6ZuM dq7KXM/w9EUCLOZ2PzqeM1iQYLWfnxkZXrdJY= Subject: Re: [PATCH v8 5/8] Loongson: YeeLoong: add hardware monitoring driver From: Wu Zhangjin Reply-To: wuzhangjin@gmail.com To: Pavel Machek 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 In-Reply-To: <20091207080446.GB23088@elf.ucw.cz> References: <20091206084717.GD2766@ucw.cz> <1260147298.3126.2.camel@falcon.domain.org> <20091207080446.GB23088@elf.ucw.cz> Content-Type: text/plain; charset="UTF-8" Organization: DSLab, Lanzhou University, China Date: Mon, 07 Dec 2009 17:41:10 +0800 Message-ID: <1260178870.9092.34.camel@falcon.domain.org> Mime-Version: 1.0 X-Mailer: Evolution 2.28.1 Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 1256 Lines: 42 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! BTW: This part of source code was written by another EC guy, not checked it carefully, sorry ;) Best Regards, Wu Zhangjin -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/