diff options
| author | Hakan Berg <hakan.berg@stericsson.com> | 2012-07-17 14:17:16 +0200 |
|---|---|---|
| committer | Lee Jones <lee.jones@linaro.org> | 2013-03-07 12:35:44 +0800 |
| commit | 908fe8d6a575e2bdf349ba8635b862eeb91f7ade (patch) | |
| tree | 863d1d0caffb4dfb84a118c0d885ce0c773b080a /drivers/power/ab8500_btemp.c | |
| parent | d4f510f6c3f579bac0dbeaa8dc7c2dc768c31786 (diff) | |
| download | linux-908fe8d6a575e2bdf349ba8635b862eeb91f7ade.tar.bz2 | |
ab8500-btemp: Filter btemp readings
Battery tempreature readings sometimes fail 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 <hakan.berg@stericsson.com>
Signed-off-by: Lee Jones <lee.jones@linaro.org>
Reviewed-by: Marcus COOPER <marcus.xm.cooper@stericsson.com>
Reviewed-by: Martin SJOBLOM <martin.w.sjoblom@stericsson.com>
Reviewed-by: Rabin VINCENT <rabin.vincent@stericsson.com>
Diffstat (limited to 'drivers/power/ab8500_btemp.c')
| -rw-r--r-- | 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 07689064996e..fa60e3ac33a3 100644 --- a/drivers/power/ab8500_btemp.c +++ b/drivers/power/ab8500_btemp.c @@ -76,8 +76,8 @@ 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 @@ -604,6 +604,7 @@ 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); @@ -614,12 +615,26 @@ 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->bm->temp_interval_chg; |