power: pm8921-bms: iterate rbatt algorithm
When ocv (open circuit voltage of the battery) is adjusted to match a
specific soc, rbatt (the battery resistance) changes too. This is
because rbatt is dependent on the remaining charge which changes as
the ocv changes.
The issue we observed with this changing rbatt was the unusable charge
changes which causes the soc to move away from the soc the algorithm
attempts to match.
To get around this issue adjust both the rbatt and ocv in a iterative
fashion until rbatt value stabilizes.
Change-Id: Id3e36c1a8361a6d71b63fca3e6b0c2a4a9bb7e06
Signed-off-by: Abhijeet Dharmapurikar <adharmap@codeaurora.org>
diff --git a/drivers/power/pm8921-bms.c b/drivers/power/pm8921-bms.c
index 5e58249..b6f0374 100644
--- a/drivers/power/pm8921-bms.c
+++ b/drivers/power/pm8921-bms.c
@@ -1529,89 +1529,30 @@
}
EXPORT_SYMBOL(pm8921_bms_invalidate_shutdown_soc);
-static void adjust_rc_and_uuc_for_shutdown_soc(
- struct pm8921_bms_chip *chip,
- int batt_temp,
- int chargecycles,
- int fcc_uah,
- int uuc_uah,
- int cc_uah,
- int remaining_charge_uah,
- int rbatt,
- int *ret_rc,
- int *ret_uuc,
- int *ret_rbatt)
+static void find_ocv_for_soc(struct pm8921_bms_chip *chip,
+ int batt_temp,
+ int chargecycles,
+ int fcc_uah,
+ int uuc_uah,
+ int cc_uah,
+ int shutdown_soc,
+ int *rc_uah,
+ int *ocv_uv)
{
- s64 new_rc;
- int new_uuc;
- int new_rbatt;
- int pc;
- int ocv, ocv_uv;
+ s64 rc;
+ int pc, new_pc;
int batt_temp_degc = batt_temp / 10;
- int new_pc;
- int shutdown_soc;
+ int ocv;
- mutex_lock(&soc_invalidation_mutex);
- shutdown_soc = chip->shutdown_soc;
- /*
- * value of zero means the shutdown soc should not be used, the battery
- * was removed for extended period, the coincell capacitor could have
- * drained
- * shutdown_soc_invalid means the shutdown soc should not be used,
- * the battery was removed for a small period
- */
- if (shutdown_soc == 0 || shutdown_soc_invalid) {
- new_rc = remaining_charge_uah;
- new_uuc = uuc_uah;
- new_rbatt = rbatt;
- goto out;
- }
-
- /* value of 0xFF means shutdown soc was 0% */
- if (shutdown_soc == 0xFF)
- shutdown_soc = 0;
-
- /* step 1 get to a reasonable rbatt */
- if (chip->last_ocv_uv < chip->v_cutoff * 1000) {
- int new_pc_for_rbatt;
- int iavg_ua;
- int iavg_ma;
- int soc_for_rbatt;
-
- new_pc_for_rbatt = calculate_pc(chip, chip->v_cutoff * 1000,
- batt_temp, chargecycles);
-
- soc_for_rbatt
- = (new_pc_for_rbatt * fcc_uah - cc_uah * 100) / fcc_uah;
- new_rbatt = get_rbatt(chip, soc_for_rbatt, batt_temp);
-
- pm8921_bms_get_battery_current(&iavg_ua);
- iavg_ma = iavg_ua / 1000;
- if (iavg_ma < 0)
- iavg_ma = CHARGING_IAVG_MA;
-
- new_uuc = calculate_uuc_uah_at_given_current(chip,
- batt_temp, chargecycles,
- new_rbatt, fcc_uah, iavg_ma);
-
- pr_debug("new pc = %d, soc_rbatt = %d, new_rbatt = %d,\n",
- new_pc_for_rbatt, soc_for_rbatt, new_rbatt);
- pr_debug("iavg_ma = %d, new_uuc = %d\n", iavg_ma, new_uuc);
- } else {
- new_rbatt = rbatt;
- new_uuc = uuc_uah;
- }
-
- /* step 2 adjust rc using the new uuc */
- new_rc = (s64)shutdown_soc * (fcc_uah - new_uuc);
- new_rc = div_s64(new_rc, 100) + cc_uah + new_uuc;
- pc = DIV_ROUND_CLOSEST((int)new_rc * 100, fcc_uah);
+ rc = (s64)shutdown_soc * (fcc_uah - uuc_uah);
+ rc = div_s64(rc, 100) + cc_uah + uuc_uah;
+ pc = DIV_ROUND_CLOSEST((int)rc * 100, fcc_uah);
pc = clamp(pc, 0, 100);
ocv = interpolate_ocv(chip, batt_temp_degc, pc);
- pr_debug("To force shutdown_soc = %d, new_rc = %d, pc = %d, ocv mv = %d\n",
- shutdown_soc, (int)new_rc, pc, ocv);
+ pr_debug("s_soc = %d, fcc = %d uuc = %d rc = %d, pc = %d, ocv mv = %d\n",
+ shutdown_soc, fcc_uah, uuc_uah, (int)rc, pc, ocv);
new_pc = interpolate_pc(chip, batt_temp_degc, ocv);
pr_debug("test revlookup pc = %d for ocv = %d\n", new_pc, ocv);
@@ -1626,14 +1567,85 @@
pr_debug("test revlookup pc = %d for ocv = %d\n", new_pc, ocv);
}
- ocv_uv = ocv * 1000;
+ *ocv_uv = ocv * 1000;
+ *rc_uah = (int)rc;
+}
+
+static void adjust_rc_and_uuc_for_shutdown_soc(
+ struct pm8921_bms_chip *chip,
+ int batt_temp,
+ int chargecycles,
+ int fcc_uah,
+ int uuc_uah,
+ int cc_uah,
+ int remaining_charge_uah,
+ int rbatt,
+ int *ret_rc,
+ int *ret_uuc,
+ int *ret_rbatt)
+{
+ int new_rbatt;
+ int ocv_uv;
+ int shutdown_soc;
+ int rc_uah;
+ int soc_rbatt;
+ int iavg_ua, iavg_ma;
+ int num_tries = 0;
+
+ mutex_lock(&soc_invalidation_mutex);
+ shutdown_soc = chip->shutdown_soc;
+ /*
+ * value of zero means the shutdown soc should not be used, the battery
+ * was removed for extended period, the coincell capacitor could have
+ * drained
+ * shutdown_soc_invalid means the shutdown soc should not be used,
+ * the battery was removed for a small period
+ */
+ if (shutdown_soc == 0 || shutdown_soc_invalid) {
+ rc_uah = remaining_charge_uah;
+ goto out;
+ }
+
+ /* value of 0xFF means shutdown soc was 0% */
+ if (shutdown_soc == 0xFF)
+ shutdown_soc = 0;
+
+ pm8921_bms_get_battery_current(&iavg_ua);
+ iavg_ma = iavg_ua / 1000;
+ if (iavg_ma < 0)
+ iavg_ma = CHARGING_IAVG_MA;
+
+recalculate_ocv:
+
+ find_ocv_for_soc(chip, batt_temp, chargecycles,
+ fcc_uah, uuc_uah, cc_uah,
+ shutdown_soc,
+ &rc_uah, &ocv_uv);
+
+ soc_rbatt = div_s64((rc_uah - cc_uah) * 100, fcc_uah);
+ new_rbatt = get_rbatt(chip, soc_rbatt, batt_temp);
+ pr_debug("for s_soc = %d rc_uah = %d ocv_uv = %d, soc_rbatt = %d rbatt = %d\n",
+ shutdown_soc, rc_uah, ocv_uv, soc_rbatt, new_rbatt);
+ if (abs(new_rbatt - rbatt) > 20 && num_tries < 10) {
+ rbatt = new_rbatt;
+ uuc_uah = calculate_uuc_uah_at_given_current(chip,
+ batt_temp, chargecycles,
+ new_rbatt, fcc_uah, iavg_ma);
+
+ pr_debug("rbatt not settled uuc = %d for rbatt = %d iavg_ma = %d num_tries = %d\n",
+ uuc_uah, rbatt, iavg_ma, num_tries);
+ num_tries++;
+ goto recalculate_ocv;
+ }
+ pr_debug("DONE for s_soc = %d rc_uah = %d ocv_uv = %d, rbatt = %d\n",
+ shutdown_soc, rc_uah, ocv_uv, new_rbatt);
chip->pon_ocv_uv = chip->last_ocv_uv;
chip->last_ocv_uv = ocv_uv;
out:
- *ret_rbatt = new_rbatt;
- *ret_rc = (int)new_rc;
- *ret_uuc = new_uuc;
+ *ret_rbatt = rbatt;
+ *ret_rc = rc_uah;
+ *ret_uuc = uuc_uah;
mutex_unlock(&soc_invalidation_mutex);
}