From: Hakan Berg <hakan.b...@stericsson.com>
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 <hakan.b...@stericsson.com>
Signed-off-by: Mathieu Poirier <mathieu.poir...@linaro.org>
Reviewed-by: Marcus COOPER <marcus.xm.coo...@stericsson.com>
Reviewed-by: Martin SJOBLOM <martin.w.sjob...@stericsson.com>
Reviewed-by: Rabin VINCENT <rabin.vinc...@stericsson.com>
---
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
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