From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1756211Ab2LMPWp (ORCPT ); Thu, 13 Dec 2012 10:22:45 -0500 Received: from mail-we0-f174.google.com ([74.125.82.174]:38422 "EHLO mail-we0-f174.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1756026Ab2LMPWZ (ORCPT ); Thu, 13 Dec 2012 10:22:25 -0500 From: Lee Jones To: linux-kernel@vger.kernel.org Cc: cbou@mail.ru, Paer-Olof Haakansson , Lee Jones , =?UTF-8?q?Henrik=20S=C3=B6lver?= Subject: [PATCH 18/18] Power: ab8500_fg: Overflow in current calculation Date: Thu, 13 Dec 2012 15:21:41 +0000 Message-Id: <1355412102-14265-19-git-send-email-lee.jones@linaro.org> X-Mailer: git-send-email 1.7.9.5 In-Reply-To: <1355412102-14265-1-git-send-email-lee.jones@linaro.org> References: <1355412102-14265-1-git-send-email-lee.jones@linaro.org> MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org From: Paer-Olof Haakansson When calculating the average current the nominator will overflow when the charging current is high. Signed-off-by: Lee Jones Signed-off-by: Henrik Sölver Reviewed-by: Par-Olof HAKANSSON Reviewed-by: Jonas ABERG Tested-by: Par-Olof HAKANSSON --- drivers/power/ab8500_fg.c | 9 ++++----- 1 file changed, 4 insertions(+), 5 deletions(-) diff --git a/drivers/power/ab8500_fg.c b/drivers/power/ab8500_fg.c index ec122d0..ba1a087 100644 --- a/drivers/power/ab8500_fg.c +++ b/drivers/power/ab8500_fg.c @@ -804,12 +804,9 @@ static void ab8500_fg_acc_cur_work(struct work_struct *work) /* * Convert to unit value in mA - * Full scale input voltage is - * 66.660mV => LSB = 66.660mV/(4096*res) = 1.627mA - * Given a 250ms conversion cycle time the LSB corresponds - * to 112.9 nAh. Convert to current by dividing by the conversion + * by dividing by the conversion * time in hours (= samples / (3600 * 4)h) - * 112.9nAh assumes 10mOhm, but fg_res is in 0.1mOhm + * and multiply with 1000 */ di->avg_curr = (val * QLSB_NANO_AMP_HOURS_X10 * 36) / (1000 * di->bm->fg_res * (di->fg_samples / 4)); @@ -820,6 +817,8 @@ static void ab8500_fg_acc_cur_work(struct work_struct *work) queue_work(di->fg_wq, &di->fg_work); + dev_dbg(di->dev, "fg_res: %d, fg_samples: %d, gasg: %d, accu_charge: %d \n", + di->bm->fg_res, di->fg_samples, val, di->accu_charge); return; exit: dev_err(di->dev, -- 1.7.9.5