[PATCH 2/2] power: supply: qcom_battmgr: expose CHARGE_NOW on SM8350-class firmware

[Jan-Michael Brummer <jan.brummer@tabos.org>]

The SM8350-class firmware does not implement a dedicated 'charge now'
property. It does however report BATT_CHG_COUNTER, and on this class of
firmware that value is the remaining charge in uAh rather than a
monotonic counter. Measured on a Fairphone 5 with charge_full at
4116000 uAh:

  BATT_CHG_COUNTER   reported capacity   counter / charge_full
  2434614            59%                 59.1%
  3525354            85%                 85.6%

Map POWER_SUPPLY_PROP_CHARGE_NOW onto the same firmware property and
store the value in status.capacity, which the CHARGE_NOW/ENERGY_NOW case
of qcom_battmgr_bat_get_property() already reads.

Together with the preceding patch this gives userspace both the full
charge and the current charge. UPower now derives an energy level and
runtime estimates in both directions:

    state:               discharging      state:               charging
    energy:              14.4347 Wh       energy:              15.6003 Wh
    energy-full:         16.8807 Wh       energy-full:         18.1505 Wh
    energy-rate:         3.39313 W        energy-rate:         7.3492 W
    time to empty:       4.3 hours        time to full:        20.8 minutes

Signed-off-by: Jan-Michael Brummer <jan.brummer@tabos.org>
---
 drivers/power/supply/qcom_battmgr.c | 8 +++++++-
 1 file changed, 7 insertions(+), 1 deletion(-)

diff --git a/drivers/power/supply/qcom_battmgr.c b/drivers/power/supply/qcom_battmgr.c
index 98a70e1..f7c120f 100644
--- a/drivers/power/supply/qcom_battmgr.c
+++ b/drivers/power/supply/qcom_battmgr.c
@@ -441,6 +441,7 @@ static const u8 sm8350_bat_prop_map[] = {
 	[POWER_SUPPLY_PROP_CYCLE_COUNT] = BATT_CYCLE_COUNT,
 	[POWER_SUPPLY_PROP_CHARGE_FULL_DESIGN] =  BATT_CHG_FULL_DESIGN,
 	[POWER_SUPPLY_PROP_CHARGE_FULL] = BATT_CHG_FULL,
+	[POWER_SUPPLY_PROP_CHARGE_NOW] = BATT_CHG_COUNTER,
 	[POWER_SUPPLY_PROP_MODEL_NAME] = BATT_MODEL_NAME,
 	[POWER_SUPPLY_PROP_TIME_TO_FULL_AVG] = BATT_TTF_AVG,
 	[POWER_SUPPLY_PROP_TIME_TO_EMPTY_AVG] = BATT_TTE_AVG,
@@ -878,6 +879,7 @@ static const enum power_supply_property sm8350_bat_props[] = {
 	POWER_SUPPLY_PROP_CYCLE_COUNT,
 	POWER_SUPPLY_PROP_CHARGE_FULL_DESIGN,
 	POWER_SUPPLY_PROP_CHARGE_FULL,
+	POWER_SUPPLY_PROP_CHARGE_NOW,
 	POWER_SUPPLY_PROP_MODEL_NAME,
 	POWER_SUPPLY_PROP_TIME_TO_FULL_AVG,
 	POWER_SUPPLY_PROP_TIME_TO_EMPTY_AVG,
@@ -910,6 +912,7 @@ static const enum power_supply_property sm8550_bat_props[] = {
 	POWER_SUPPLY_PROP_CYCLE_COUNT,
 	POWER_SUPPLY_PROP_CHARGE_FULL_DESIGN,
 	POWER_SUPPLY_PROP_CHARGE_FULL,
+	POWER_SUPPLY_PROP_CHARGE_NOW,
 	POWER_SUPPLY_PROP_MODEL_NAME,
 	POWER_SUPPLY_PROP_TIME_TO_FULL_AVG,
 	POWER_SUPPLY_PROP_TIME_TO_EMPTY_AVG,
@@ -1442,7 +1445,10 @@ static void qcom_battmgr_sm8350_callback(struct qcom_battmgr *battmgr,
 			battmgr->info.technology = le32_to_cpu(resp->intval.value);
 			break;
 		case BATT_CHG_COUNTER:
-			battmgr->info.charge_count = le32_to_cpu(resp->intval.value);
+			val = le32_to_cpu(resp->intval.value);
+			battmgr->info.charge_count = val;
+			/* the firmware reports the remaining charge here */
+			battmgr->status.capacity = val;
 			break;
 		case BATT_CYCLE_COUNT:
 			battmgr->info.cycle_count = le32_to_cpu(resp->intval.value);