power: pm8921-bms: introduce configurable corrections
There are situations when the corrections can cause linearity issues.
Provide a scheme to limit the corrections via a configurable parameters.
The corrections were introduced to prevent battery dipping below UVLO.
If the battery were in the flat portion of the SOC curve a small error
in OCV measurement could drift the SOC by a large amount. Corrections
are important if the OCV falls in this range. Hence introduce two
parameters to limit the corrections based on a OCV threshold - one when
it is above 3.8 volts, where corrections could be low and the other
when the OCV is lower and 3.8 (flat portion) where corrections should be
high.
Also there are instances when the SOC appears stuck at 1% for a long
time. This is because the algorithm doesn't allow the soc to drop to 0%
if the estimated soc is high. Provide a configurable level for the
estimated SOC below which, the calculated soc can go to 0%.
Change-Id: I265e1ea41681813ec6add6eea2a440c6e239a5dc
Signed-off-by: Abhijeet Dharmapurikar <adharmap@codeaurora.org>
diff --git a/drivers/power/pm8921-bms.c b/drivers/power/pm8921-bms.c
index e38ce9c..9087f6f 100644
--- a/drivers/power/pm8921-bms.c
+++ b/drivers/power/pm8921-bms.c
@@ -170,6 +170,9 @@
int disable_flat_portion_ocv;
int ocv_dis_high_soc;
int ocv_dis_low_soc;
+ int high_ocv_correction_limit_uv;
+ int low_ocv_correction_limit_uv;
+ int hold_soc_est;
int prev_vbat_batt_terminal_uv;
int vbatt_cutoff_count;
int low_voltage_detect;
@@ -1861,6 +1864,7 @@
int m = 0;
int rc = 0;
int delta_ocv_uv_limit = 0;
+ int correction_limit_uv = 0;
rc = pm8921_bms_get_simultaneous_battery_voltage_and_current(
&ibat_ua,
@@ -1964,6 +1968,22 @@
pr_debug("new delta ocv = %d\n", delta_ocv_uv);
}
+ if (chip->last_ocv_uv > 3800000)
+ correction_limit_uv = the_chip->high_ocv_correction_limit_uv;
+ else
+ correction_limit_uv = the_chip->low_ocv_correction_limit_uv;
+
+ if (abs(delta_ocv_uv) > correction_limit_uv) {
+ pr_debug("limiting delta ocv %d limit = %d\n", delta_ocv_uv,
+ correction_limit_uv);
+
+ if (delta_ocv_uv > 0)
+ delta_ocv_uv = correction_limit_uv;
+ else
+ delta_ocv_uv = -1 * correction_limit_uv;
+ pr_debug("new delta ocv = %d\n", delta_ocv_uv);
+ }
+
chip->last_ocv_uv -= delta_ocv_uv;
if (chip->last_ocv_uv >= chip->max_voltage_uv)
@@ -1980,7 +2000,7 @@
* if soc_new is ZERO force it higher so that phone doesnt report soc=0
* soc = 0 should happen only when soc_est == 0
*/
- if (soc_new == 0 && soc_est != 0)
+ if (soc_new == 0 && soc_est >= the_chip->hold_soc_est)
soc_new = 1;
soc = soc_new;
@@ -3384,6 +3404,11 @@
chip->ocv_dis_high_soc = pdata->ocv_dis_high_soc;
chip->ocv_dis_low_soc = pdata->ocv_dis_low_soc;
+ chip->high_ocv_correction_limit_uv
+ = pdata->high_ocv_correction_limit_uv;
+ chip->low_ocv_correction_limit_uv = pdata->low_ocv_correction_limit_uv;
+ chip->hold_soc_est = pdata->hold_soc_est;
+
chip->alarm_low_mv = pdata->alarm_low_mv;
chip->alarm_high_mv = pdata->alarm_high_mv;
chip->low_voltage_detect = pdata->low_voltage_detect;