[PATCH 12/15] power: supply: cpcap-battery: stabilize charge_full value

[Arthur Demchenkov <spinal.by@gmail.com>]

It will not grow after the battery met "fully charged" state. This is
needed because of how constant voltage charging works. If we want "fully
charged" state to be reported in a user expected manner we are forced to
do it when the charging current is low enough, but not a zero value.

So, we report "battery full" when the charging current is as low as 100
mA. But the actual charging continues until the user disconnects the
charger. It means that a few mAh will be added to the reported
charge_full value, which the user shouldn't see. With that purpose we
clamp the charge_now value to not exceed charge_full.

Signed-off-by: Arthur Demchenkov <spinal.by@gmail.com>
---
 drivers/power/supply/cpcap-battery.c | 29 +++++++++++++++--------------
 1 file changed, 15 insertions(+), 14 deletions(-)

diff --git a/drivers/power/supply/cpcap-battery.c b/drivers/power/supply/cpcap-battery.c
index 66ea1a718e02..517acdfa6009 100644
--- a/drivers/power/supply/cpcap-battery.c
+++ b/drivers/power/supply/cpcap-battery.c
@@ -469,15 +469,15 @@ static int cpcap_battery_update_status(struct cpcap_battery_ddata *ddata)
 	if (cpcap_battery_full(ddata)) {
 		full = cpcap_battery_get_full(ddata);
 		/* Update full state value? */
-		if (latest->counter_uah <= full->counter_uah ||
-		    !full->voltage) {
+		if (!full->voltage) {
 			memcpy(full, latest, sizeof(*full));
 
 			empty = cpcap_battery_get_empty(ddata);
-			if (empty->voltage && empty->voltage != -1)
+			if (empty->voltage) {
 				ddata->charge_full =
 					empty->counter_uah - full->counter_uah;
-			else if (ddata->charge_full) {
+				empty->voltage = -1;
+			} else if (ddata->charge_full) {
 				/* Initialize with user provided data */
 				empty->counter_uah =
 					full->counter_uah + ddata->charge_full;
@@ -488,18 +488,15 @@ static int cpcap_battery_update_status(struct cpcap_battery_ddata *ddata)
 	} else if (cpcap_battery_low(ddata)) {
 		empty = cpcap_battery_get_empty(ddata);
 		/* Update empty state value? */
-		if (latest->counter_uah >= empty->counter_uah ||
-		    !empty->voltage) {
+		if (!empty->voltage || empty->voltage == -1) {
 			memcpy(empty, latest, sizeof(*empty));
 
 			full = cpcap_battery_get_full(ddata);
-			if (full->voltage)
+			if (full->voltage) {
 				ddata->charge_full =
 					empty->counter_uah - full->counter_uah;
-			else if (ddata->charge_full)
-				/* Initialize with user provided data */
-				full->counter_uah =
-					empty->counter_uah - ddata->charge_full;
+				full->voltage = 0;
+			}
 		}
 	}
 
@@ -638,9 +635,9 @@ static int cpcap_battery_get_property(struct power_supply *psy,
 		empty = cpcap_battery_get_empty(ddata);
 		if (!empty->voltage || !ddata->charge_full)
 			return -ENODATA;
-		val->intval = (empty->counter_uah -
-			       latest->counter_uah) * 100;
-		val->intval /= ddata->charge_full;
+		val->intval = empty->counter_uah - latest->counter_uah;
+		val->intval = clamp(val->intval, 0, ddata->charge_full);
+		val->intval = val->intval * 100 / ddata->charge_full;
 		break;
 	case POWER_SUPPLY_PROP_CAPACITY_LEVEL:
 		val->intval = cpcap_battery_get_capacity_level(ddata);
@@ -650,6 +647,10 @@ static int cpcap_battery_get_property(struct power_supply *psy,
 		if (!empty->voltage)
 			return -ENODATA;
 		val->intval = empty->counter_uah - latest->counter_uah;
+		if (val->intval < 0)
+			val->intval = 0;
+		else if (ddata->charge_full && ddata->charge_full < val->intval)
+			val->intval = ddata->charge_full;
 		break;
 	case POWER_SUPPLY_PROP_CHARGE_FULL:
 		if (!ddata->charge_full)
-- 
2.11.0