power: pm8921-bms: adjust soc
It was observed that the soc(state of charge) reported by the bms was off.
This lead to the phone shutting off because the battery voltage got very
low (UVLO). The expected behaviour is that as battery gets depleted the soc
is reported as 0 by the driver and the system executes a clean shutdown.
Avoid this situation by estimating the instantaneous SOC and adjusting the
reported SOC. The reported SOC is such that it approaches the estimated
soc.
The algorithm to calcualte soc est is as follows
1. Get the simultaneous vbatt and ibatt readings.
2. Get the rbatt of the battery
3. estimated open circuit voltage ocv_est = vbatt + (rbatt * ibatt)
4. calculate rc_est = calcualte_pc(ocv_est) * fcc;
5. soc_est = (rc_est - uuc)/ (fcc - uuc)
The soc est indicates what would be the current soc of the battery solely
based on instantaneous ocv (open circuit voltage) of the battery.
Note that soc_est is subject to fluctuations as the load on the battery
changes - it needs to be weighted accordingly. Let "n" inversely define how
quickly soc approaches the soc_est i.e. a high value in n indicates the
approach is slow and a low value of n indicates we approach the fast. This
implies that the value of n should be smaller as soc_est goes to 0.
Choose a value of n based on where soc and soc_est
are. Experiments showed that
n = min(200, max(1, soc + soc_est + last_soc_est))
yields expected adjusted results. last_soc_est is the soc_est the last time
soc request was made.
Once n is calculated, the last_ocv_uv is adjusted such that soc moves 1/n
steps closer to soc_est. This new soc value "soc_new" is the adjusted
value reported to the userspace.
CRs-Fixed: 349817
Change-Id: I807f051fc1e63b40740e0e0c3a50857ad958bcb6
Signed-off-by: Abhijeet Dharmapurikar <adharmap@codeaurora.org>
diff --git a/drivers/power/pm8921-bms.c b/drivers/power/pm8921-bms.c
index ce748f5..aa1a589 100644
--- a/drivers/power/pm8921-bms.c
+++ b/drivers/power/pm8921-bms.c
@@ -78,9 +78,13 @@
/**
* struct pm8921_bms_chip -
* @bms_output_lock: lock to prevent concurrent bms reads
- * @bms_100_lock: lock to prevent concurrent updates to values that force
- * 100% charge
*
+ * @last_ocv_uv_mutex: mutex to protect simultaneous invocations of calculate
+ * state of charge, note that last_ocv_uv could be
+ * changed as soc is adjusted. This mutex protects
+ * simultaneous updates of last_ocv_uv as well. This mutex
+ * also protects changes to *_at_100 variables used in
+ * faking 100% SOC.
*/
struct pm8921_bms_chip {
struct device *dev;
@@ -111,7 +115,6 @@
unsigned int pmic_bms_irq[PM_BMS_MAX_INTS];
DECLARE_BITMAP(enabled_irqs, PM_BMS_MAX_INTS);
struct mutex bms_output_lock;
- spinlock_t bms_100_lock;
struct single_row_lut *adjusted_fcc_temp_lut;
unsigned int charging_began;
unsigned int start_percent;
@@ -127,6 +130,8 @@
int amux_2_trim_delta;
uint16_t prev_last_good_ocv_raw;
unsigned int rconn_mohm;
+ struct mutex last_ocv_uv_mutex;
+ int last_ocv_uv;
};
static struct pm8921_bms_chip *the_chip;
@@ -144,7 +149,6 @@
module_param(last_charge_increase, int, 0644);
static int last_rbatt = -EINVAL;
-static int last_ocv_uv = -EINVAL;
static int last_soc = -EINVAL;
static int last_real_fcc_mah = -EINVAL;
static int last_real_fcc_batt_temp = -EINVAL;
@@ -163,7 +167,6 @@
};
module_param_cb(last_rbatt, &bms_param_ops, &last_rbatt, 0644);
-module_param_cb(last_ocv_uv, &bms_param_ops, &last_ocv_uv, 0644);
module_param_cb(last_soc, &bms_param_ops, &last_soc, 0644);
/*
@@ -957,16 +960,28 @@
adjust_pon_ocv_raw(chip, raw);
convert_vbatt_raw_to_uv(chip, usb_chg,
raw->last_good_ocv_raw, &raw->last_good_ocv_uv);
- last_ocv_uv = raw->last_good_ocv_uv;
+ chip->last_ocv_uv = raw->last_good_ocv_uv;
} else if (chip->prev_last_good_ocv_raw != raw->last_good_ocv_raw) {
chip->prev_last_good_ocv_raw = raw->last_good_ocv_raw;
convert_vbatt_raw_to_uv(chip, usb_chg,
raw->last_good_ocv_raw, &raw->last_good_ocv_uv);
- last_ocv_uv = raw->last_good_ocv_uv;
+ chip->last_ocv_uv = raw->last_good_ocv_uv;
} else {
- raw->last_good_ocv_uv = last_ocv_uv;
+ raw->last_good_ocv_uv = chip->last_ocv_uv;
}
+ /* fake a high OCV if we are just done charging */
+ if (chip->ocv_reading_at_100 != raw->last_good_ocv_raw) {
+ chip->ocv_reading_at_100 = 0;
+ chip->cc_reading_at_100 = 0;
+ } else {
+ /*
+ * force 100% ocv by selecting the highest voltage the
+ * battery could ever reach
+ */
+ raw->last_good_ocv_uv = chip->max_voltage_uv;
+ chip->last_ocv_uv = chip->max_voltage_uv;
+ }
pr_debug("0p625 = %duV\n", chip->xoadc_v0625);
pr_debug("1p25 = %duV\n", chip->xoadc_v125);
pr_debug("last_good_ocv_raw= 0x%x, last_good_ocv_uv= %duV\n",
@@ -1120,7 +1135,7 @@
cc_voltage_uv = cc;
cc_voltage_uv -= chip->cc_reading_at_100;
- pr_debug("cc = %d. after subtracting %d cc = %lld\n",
+ pr_debug("cc = %d. after subtracting 0x%x cc = %lld\n",
cc, chip->cc_reading_at_100,
cc_voltage_uv);
cc_voltage_uv = cc_to_microvolt(chip, cc_voltage_uv);
@@ -1156,25 +1171,7 @@
{
int ocv, pc;
- /* calculate remainging charge */
- ocv = 0;
- if (chip->ocv_reading_at_100 != raw->last_good_ocv_raw) {
- chip->ocv_reading_at_100 = 0;
- chip->cc_reading_at_100 = 0;
- ocv = raw->last_good_ocv_uv;
- } else {
- /*
- * force 100% ocv by selecting the highest voltage the
- * battery could every reach
- */
- ocv = chip->max_voltage_uv;
- }
-
- if (ocv == 0) {
- ocv = last_ocv_uv;
- pr_debug("ocv not available using last_ocv_uv=%d\n", ocv);
- }
-
+ ocv = raw->last_good_ocv_uv;
pc = calculate_pc(chip, ocv, batt_temp, chargecycles);
pr_debug("ocv = %d pc = %d\n", ocv, pc);
return (fcc_uah * pc) / 100;
@@ -1189,7 +1186,6 @@
int *cc_uah,
int *rbatt)
{
- unsigned long flags;
int soc_rbatt;
*fcc_uah = calculate_fcc_uah(chip, batt_temp, chargecycles);
@@ -1197,7 +1193,6 @@
*fcc_uah, batt_temp, chargecycles);
- spin_lock_irqsave(&chip->bms_100_lock, flags);
/* calculate remainging charge */
*remaining_charge_uah = calculate_remaining_charge_uah(chip, raw,
*fcc_uah, batt_temp, chargecycles);
@@ -1205,11 +1200,10 @@
/* calculate cc micro_volt_hour */
calculate_cc_uah(chip, raw->cc, cc_uah);
- pr_debug("cc_uah = %duAh raw->cc = %x cc = %lld after subtracting %d\n",
+ pr_debug("cc_uah = %duAh raw->cc = %x cc = %lld after subtracting %x\n",
*cc_uah, raw->cc,
(int64_t)raw->cc - chip->cc_reading_at_100,
chip->cc_reading_at_100);
- spin_unlock_irqrestore(&chip->bms_100_lock, flags);
soc_rbatt = ((*remaining_charge_uah - *cc_uah) * 100) / *fcc_uah;
if (soc_rbatt < 0)
@@ -1245,6 +1239,108 @@
real_fcc_uah, remaining_charge_uah, cc_uah, fcc_uah);
return real_fcc_uah;
}
+
+static int bound_soc(int soc)
+{
+ soc = max(0, soc);
+ soc = min(100, soc);
+ return soc;
+}
+
+static int last_soc_est = -EINVAL;
+static int adjust_soc(struct pm8921_bms_chip *chip, int soc, int batt_temp,
+ int rbatt , int fcc_uah, int uuc_uah, int cc_uah)
+{
+ int ibat_ua = 0, vbat_uv = 0;
+ int ocv_est_uv = 0, soc_est = 0, pc_est = 0, pc = 0;
+ int delta_ocv_uv = 0;
+ int n = 0;
+ int rc_new_uah = 0;
+ int pc_new = 0;
+ int soc_new = 0;
+ int m = 0;
+
+ pm8921_bms_get_simultaneous_battery_voltage_and_current(&ibat_ua,
+ &vbat_uv);
+
+ if (ibat_ua < 0)
+ goto out;
+ ocv_est_uv = vbat_uv + (ibat_ua * rbatt)/1000;
+ pc_est = calculate_pc(chip, ocv_est_uv, batt_temp, last_chargecycles);
+ soc_est = div_s64((s64)fcc_uah * pc_est - uuc_uah*100,
+ (s64)fcc_uah - uuc_uah);
+ soc_est = bound_soc(soc_est);
+
+ /*
+ * do not adjust if soc_est is between 45 and 25 OR soc_est is
+ * same as what bms calculated
+ */
+ if (is_between(45, 25, soc_est) || soc_est == soc)
+ goto out;
+
+ if (last_soc_est == -EINVAL)
+ last_soc_est = soc;
+
+ n = min(200, max(1 , soc + soc_est + last_soc_est));
+ /* remember the last soc_est in last_soc_est */
+ last_soc_est = soc_est;
+
+ pc = calculate_pc(chip, chip->last_ocv_uv,
+ batt_temp, last_chargecycles);
+ if (pc > 0) {
+ pc_new = calculate_pc(chip, chip->last_ocv_uv - (++m * 1000),
+ batt_temp, last_chargecycles);
+ while (pc_new == pc) {
+ /* start taking 10mV steps */
+ m = m + 10;
+ pc_new = calculate_pc(chip,
+ chip->last_ocv_uv - (m * 1000),
+ batt_temp, last_chargecycles);
+ }
+ } else {
+ /*
+ * pc is already at the lowest point,
+ * assume 1 millivolt translates to 1% pc
+ */
+ pc = 1;
+ pc_new = 0;
+ m = 1;
+ }
+
+ delta_ocv_uv = div_s64((soc - soc_est) * (s64)m * 1000,
+ n * (pc - pc_new));
+ chip->last_ocv_uv -= delta_ocv_uv;
+
+ if (chip->last_ocv_uv >= chip->max_voltage_uv)
+ chip->last_ocv_uv = chip->max_voltage_uv;
+
+ /* calculate the soc based on this new ocv */
+ pc_new = calculate_pc(chip, chip->last_ocv_uv,
+ batt_temp, last_chargecycles);
+ rc_new_uah = (fcc_uah * pc_new) / 100;
+ soc_new = (rc_new_uah - cc_uah - uuc_uah)*100 / (fcc_uah - uuc_uah);
+ soc_new = bound_soc(soc_new);
+
+ /*
+ * 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)
+ soc_new = 1;
+
+ soc = soc_new;
+
+out:
+ pr_debug("ibat_ua = %d, vbat_uv = %d, ocv_est_uv = %d, pc_est = %d, "
+ "soc_est = %d, n = %d, delta_ocv_uv = %d, last_ocv_uv = %d, "
+ "pc_new = %d, soc_new = %d\n",
+ ibat_ua, vbat_uv, ocv_est_uv, pc_est,
+ soc_est, n, delta_ocv_uv, chip->last_ocv_uv,
+ pc_new, soc_new);
+
+ return soc;
+}
+
/*
* Remaining Usable Charge = remaining_charge (charge at ocv instance)
* - coloumb counter charge
@@ -1257,7 +1353,6 @@
{
int remaining_usable_charge_uah, fcc_uah, unusable_charge_uah;
int remaining_charge_uah, soc;
- int update_userspace = 1;
int cc_uah;
int rbatt;
@@ -1302,30 +1397,31 @@
pr_err("for bad rem_usb_chg last_ocv_uv = %d"
"chargecycles = %d, batt_temp = %d"
"fcc = %d soc =%d\n",
- last_ocv_uv, chargecycles, batt_temp,
+ chip->last_ocv_uv, chargecycles, batt_temp,
fcc_uah, soc);
- update_userspace = 0;
soc = 0;
}
- if (last_soc == -EINVAL || soc <= last_soc) {
- last_soc = update_userspace ? soc : last_soc;
- return soc;
- }
+ soc = adjust_soc(chip, soc, batt_temp, rbatt,
+ fcc_uah, unusable_charge_uah, cc_uah);
- /*
- * soc > last_soc
- * the device must be charging for reporting a higher soc, if not ignore
- * this soc and continue reporting the last_soc
- */
- if (the_chip->start_percent != -EINVAL) {
+ if (last_soc == -EINVAL || soc <= last_soc) {
last_soc = soc;
} else {
- pr_debug("soc = %d reporting last_soc = %d\n", soc, last_soc);
- soc = last_soc;
+ /*
+ * soc > last_soc
+ * the device must be charging for reporting a higher soc, if
+ * not ignore this soc and continue reporting the last_soc
+ */
+ if (the_chip->start_percent != -EINVAL)
+ last_soc = soc;
+ else
+ pr_debug("soc = %d reporting last_soc = %d\n", soc,
+ last_soc);
}
- return soc;
+ pr_debug("Reported SOC = %u%%\n", last_soc);
+ return last_soc;
}
#define MIN_DELTA_625_UV 1000
static void calib_hkadc(struct pm8921_bms_chip *chip)
@@ -1452,6 +1548,7 @@
int batt_temp, rc;
struct pm8xxx_adc_chan_result result;
struct pm8921_soc_params raw;
+ int soc;
if (!the_chip) {
pr_err("called before initialization\n");
@@ -1468,10 +1565,13 @@
result.measurement);
batt_temp = (int)result.physical;
+ mutex_lock(&the_chip->last_ocv_uv_mutex);
read_soc_params_raw(the_chip, &raw);
- return calculate_state_of_charge(the_chip, &raw,
+ soc = calculate_state_of_charge(the_chip, &raw,
batt_temp, last_chargecycles);
+ mutex_unlock(&the_chip->last_ocv_uv_mutex);
+ return soc;
}
EXPORT_SYMBOL_GPL(pm8921_bms_get_percent_charge);
@@ -1501,6 +1601,8 @@
result.measurement);
batt_temp = (int)result.physical;
+ mutex_lock(&the_chip->last_ocv_uv_mutex);
+
read_soc_params_raw(the_chip, &raw);
calculate_soc_params(the_chip, &raw, batt_temp, last_chargecycles,
@@ -1509,6 +1611,8 @@
&remaining_charge_uah,
&cc_uah,
&rbatt);
+ mutex_unlock(&the_chip->last_ocv_uv_mutex);
+
return rbatt;
}
EXPORT_SYMBOL_GPL(pm8921_bms_get_rbatt);
@@ -1556,10 +1660,13 @@
result.measurement);
batt_temp = (int)result.physical;
+ mutex_lock(&the_chip->last_ocv_uv_mutex);
read_soc_params_raw(the_chip, &raw);
the_chip->start_percent = calculate_state_of_charge(the_chip, &raw,
batt_temp, last_chargecycles);
+ mutex_unlock(&the_chip->last_ocv_uv_mutex);
+
bms_start_percent = the_chip->start_percent;
bms_start_ocv_uv = raw.last_good_ocv_uv;
calculate_cc_uah(the_chip, raw.cc, &bms_start_cc_uah);
@@ -1590,13 +1697,16 @@
result.measurement);
batt_temp = (int)result.physical;
+ mutex_lock(&the_chip->last_ocv_uv_mutex);
+
read_soc_params_raw(the_chip, &raw);
calculate_cc_uah(the_chip, raw.cc, &bms_end_cc_uah);
+ bms_end_ocv_uv = raw.last_good_ocv_uv;
+
if (is_battery_full
&& the_chip->start_percent <= MIN_START_PERCENT_FOR_LEARNING) {
- unsigned long flags;
int fcc_uah, new_fcc_uah, delta_fcc_uah;
new_fcc_uah = calculate_real_fcc_uah(the_chip, &raw,
@@ -1627,20 +1737,24 @@
last_real_fcc_batt_temp = batt_temp;
readjust_fcc_table();
- spin_lock_irqsave(&the_chip->bms_100_lock, flags);
+ }
+
+ if (is_battery_full) {
the_chip->ocv_reading_at_100 = raw.last_good_ocv_raw;
the_chip->cc_reading_at_100 = raw.cc;
- spin_unlock_irqrestore(&the_chip->bms_100_lock, flags);
- pr_debug("EOC ocv_reading = 0x%x cc = %d\n",
+
+ the_chip->last_ocv_uv = the_chip->max_voltage_uv;
+ raw.last_good_ocv_uv = the_chip->max_voltage_uv;
+ pr_debug("EOC ocv_reading = 0x%x cc = 0x%x\n",
the_chip->ocv_reading_at_100,
the_chip->cc_reading_at_100);
}
the_chip->end_percent = calculate_state_of_charge(the_chip, &raw,
batt_temp, last_chargecycles);
+ mutex_unlock(&the_chip->last_ocv_uv_mutex);
bms_end_percent = the_chip->end_percent;
- bms_end_ocv_uv = raw.last_good_ocv_uv;
if (the_chip->end_percent > the_chip->start_percent) {
last_charge_increase +=
@@ -1804,6 +1918,8 @@
chip->batt_temp_channel, rc);
}
chip->batt_temp_suspend = (int)result.physical;
+
+ mutex_lock(&chip->last_ocv_uv_mutex);
read_soc_params_raw(chip, &raw);
fcc_uah = calculate_fcc_uah(chip,
@@ -1818,12 +1934,14 @@
/* calculate cc micro_volt_hour */
calculate_cc_uah(chip, raw.cc, &cc_uah);
- pr_debug("cc_uah = %duAh raw->cc = %x cc = %lld after subtracting %d\n",
+ pr_debug("cc_uah = %duAh raw->cc = %x cc = %lld after subtracting %x\n",
cc_uah, raw.cc,
(int64_t)raw.cc - chip->cc_reading_at_100,
chip->cc_reading_at_100);
chip->soc_rbatt_suspend = ((remaining_charge_uah - cc_uah) * 100)
/ fcc_uah;
+ mutex_unlock(&chip->last_ocv_uv_mutex);
+
return 0;
}
@@ -1911,9 +2029,9 @@
pr_err("failed to read adc based ocv_uv rc = %d\n", rc);
ocv_uv = DEFAULT_OCV_MICROVOLTS;
}
- last_ocv_uv = ocv_uv;
}
- pr_debug("ocv_uv = %d last_ocv_uv = %d\n", ocv_uv, last_ocv_uv);
+ chip->last_ocv_uv = ocv_uv;
+ pr_debug("ocv_uv = %d last_ocv_uv = %d\n", ocv_uv, chip->last_ocv_uv);
}
static int64_t read_battery_id(struct pm8921_bms_chip *chip)
@@ -2314,8 +2432,9 @@
pr_err("Cannot allocate pm_bms_chip\n");
return -ENOMEM;
}
+
mutex_init(&chip->bms_output_lock);
- spin_lock_init(&chip->bms_100_lock);
+ mutex_init(&chip->last_ocv_uv_mutex);
chip->dev = &pdev->dev;
chip->r_sense = pdata->r_sense;
chip->i_test = pdata->i_test;
@@ -2387,7 +2506,7 @@
get_battery_uvolts(chip, &vbatt);
pr_info("OK battery_capacity_at_boot=%d volt = %d ocv = %d\n",
pm8921_bms_get_percent_charge(),
- vbatt, last_ocv_uv);
+ vbatt, chip->last_ocv_uv);
return 0;
free_irqs: