From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1758266Ab2IYQS1 (ORCPT ); Tue, 25 Sep 2012 12:18:27 -0400 Received: from mail-pb0-f46.google.com ([209.85.160.46]:60753 "EHLO mail-pb0-f46.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1757879Ab2IYQOD (ORCPT ); Tue, 25 Sep 2012 12:14:03 -0400 From: mathieu.poirier@linaro.org To: linux-kernel@vger.kernel.org, cbou@mail.ru, dwmw2@infradead.org Cc: mathieu.poirier@linaro.org Subject: [PATCH 41/57] power: ab8500_btemp: Filter btemp readings Date: Tue, 25 Sep 2012 10:12:38 -0600 Message-Id: <1348589574-25655-42-git-send-email-mathieu.poirier@linaro.org> X-Mailer: git-send-email 1.7.5.4 In-Reply-To: <1348589574-25655-1-git-send-email-mathieu.poirier@linaro.org> References: <1348589574-25655-1-git-send-email-mathieu.poirier@linaro.org> Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org From: Hakan Berg Battery tempreature readings sometimes fails and results in a value far from recent values. This patch adds a software filter that disposes such readings, by allowing direct updates on temperature only if two samples result in the same temperature. Else only allow 1 degree change from previous reported value in the direction of the new measurement. Signed-off-by: Hakan Berg Signed-off-by: Mathieu Poirier Reviewed-by: Marcus COOPER Reviewed-by: Martin SJOBLOM Reviewed-by: Rabin VINCENT --- drivers/power/ab8500_btemp.c | 27 +++++++++++++++++++++------ 1 files changed, 21 insertions(+), 6 deletions(-) diff --git a/drivers/power/ab8500_btemp.c b/drivers/power/ab8500_btemp.c index 56a3bb9..b24835f 100644 --- a/drivers/power/ab8500_btemp.c +++ b/drivers/power/ab8500_btemp.c @@ -74,8 +74,8 @@ struct ab8500_btemp_ranges { * @dev: Pointer to the structure device * @node: List of AB8500 BTEMPs, hence prepared for reentrance * @curr_source: What current source we use, in uA - * @bat_temp: Battery temperature in degree Celcius - * @prev_bat_temp Last dispatched battery temperature + * @bat_temp: Dispatched battery temperature in degree Celcius + * @prev_bat_temp Last measured battery temperature in degree Celcius * @parent: Pointer to the struct ab8500 * @gpadc: Pointer to the struct gpadc * @fg: Pointer to the struct fg @@ -608,6 +608,7 @@ static int ab8500_btemp_id(struct ab8500_btemp *di) static void ab8500_btemp_periodic_work(struct work_struct *work) { int interval; + int bat_temp; struct ab8500_btemp *di = container_of(work, struct ab8500_btemp, btemp_periodic_work.work); @@ -618,12 +619,26 @@ static void ab8500_btemp_periodic_work(struct work_struct *work) dev_warn(di->dev, "failed to identify the battery\n"); } - di->bat_temp = ab8500_btemp_measure_temp(di); - - if (di->bat_temp != di->prev_bat_temp) { - di->prev_bat_temp = di->bat_temp; + bat_temp = ab8500_btemp_measure_temp(di); + /* + * Filter battery temperature. + * Allow direct updates on temperature only if two samples result in + * same temperature. Else only allow 1 degree change from previous + * reported value in the direction of the new measurement. + */ + if (bat_temp == di->prev_bat_temp || !di->initialized) { + if (di->bat_temp != di->prev_bat_temp || !di->initialized) { + di->bat_temp = bat_temp; + power_supply_changed(&di->btemp_psy); + } + } else if (bat_temp < di->prev_bat_temp) { + di->bat_temp--; + power_supply_changed(&di->btemp_psy); + } else if (bat_temp > di->prev_bat_temp) { + di->bat_temp++; power_supply_changed(&di->btemp_psy); } + di->prev_bat_temp = bat_temp; if (di->events.ac_conn || di->events.usb_conn) interval = di->bat->temp_interval_chg; -- 1.7.5.4