[PATCH 0/2] power: supply: qcom_battmgr: report charge levels on SM8350-class firmware

[PATCH 0/2] power: supply: qcom_battmgr: report charge levels on SM8350-class firmware

[Jan-Michael Brummer]

On SM8350-class firmware (everything that is not SC8280XP/X1E80100) the
battery reports no usable charge level to userspace: charge_full and
charge_full_design fail with -ENODATA and there is no charge_now at all.
As a consequence UPower cannot derive an absolute energy level and never
shows a runtime estimate - the UI is limited to "charging"/"discharging".

Patch 1 is the actual bug: battmgr->unit is only populated from a
BATTMGR_BAT_INFO response, which this firmware class never sends, so the
mAh guard on the CHARGE_* properties always rejects them. The values are
fetched from the firmware and stored on every access, they are just
thrown away again.

Patch 2 adds CHARGE_NOW. There is no dedicated firmware property for it,
but BATT_CHG_COUNTER carries the remaining charge rather than a
monotonic counter on this firmware. This is the part I am least sure
about, since it does not match the charge_counter semantics described in
Documentation/ABI/testing/sysfs-class-power. Two measurements across the
SoC range agree with the reported capacity to within a percent, so at
least on this platform the interpretation holds. Happy to drop this
patch or to collect a full discharge curve if you prefer.

Both patches were tested on a Fairphone 5 (QCM6490) running
postmarketOS. Before the series:

    energy:              0 Wh
    energy-full:         0 Wh
    energy-rate:         12.4713 W
    percentage:          59%

After, discharging and 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

Two observations that are out of scope here but worth recording:

  - power_now reports 72097076 while current_now * voltage_now gives
    ~11.9 W, and qcom-battmgr-usb/current_now reports 11078000 against
    an input_current_limit of 3000000. Both look like unscaled firmware
    values. UPower does not use either, so this series is unaffected.

  - state_of_health reports 100 while charge_full/charge_full_design
    works out to 96.6%, so the firmware appears to derive the two
    independently.

The time-to-full estimate is optimistic compared to the firmware's own
time_to_full_avg because UPower extrapolates linearly and does not model
the CV taper. That is expected and not a regression.

Jan-Michael Brummer (2):
  power: supply: qcom_battmgr: fix CHARGE_FULL* on SM8350-class firmware
  power: supply: qcom_battmgr: expose CHARGE_NOW on SM8350-class
    firmware

 drivers/power/supply/qcom_battmgr.c | 16 +++++++++++++++-
 1 file changed, 15 insertions(+), 1 deletion(-)

[PATCH 1/2] power: supply: qcom_battmgr: fix CHARGE_FULL* on SM8350-class firmware

[Jan-Michael Brummer]

battmgr->unit is only ever assigned in the BATTMGR_BAT_INFO handler of
the SC8280XP callback. The SM8350-class firmware does not implement that
request - every property is fetched individually via
BATTMGR_BAT_PROPERTY_GET - so unit keeps its zero-initialised value,
QCOM_BATTMGR_UNIT_mWh.

POWER_SUPPLY_PROP_CHARGE_FULL and POWER_SUPPLY_PROP_CHARGE_FULL_DESIGN
are guarded by 'if (unit != QCOM_BATTMGR_UNIT_mAh) return -ENODATA;',
hence both properties always fail on these platforms, even though the
values are requested from the firmware and stored in
info.last_full_capacity and info.design_capacity on every access:

  $ cat /sys/class/power_supply/qcom-battmgr-bat/charge_full
  cat: read error: No data available

Without a full charge value userspace cannot derive an absolute energy
level, so UPower reports a zero energy level and never computes a
time-to-empty/time-to-full estimate:

    energy:              0 Wh
    energy-full:         0 Wh
    energy-rate:         12.4713 W
    percentage:          59%

The firmware of this class reports charge domain values, so set the unit
statically when registering the SM8350/SM8550 power supplies. With this
patch the properties read back consistently on a Fairphone 5:

  charge_full         4116000
  charge_full_design  4260000
  capacity            85

Fixes: 29e8142b5623 ("power: supply: Introduce Qualcomm PMIC GLINK power supply")
Signed-off-by: Jan-Michael Brummer <jan.brummer@tabos.org>
---
 drivers/power/supply/qcom_battmgr.c | 8 ++++++++
 1 file changed, 8 insertions(+)

diff --git a/drivers/power/supply/qcom_battmgr.c b/drivers/power/supply/qcom_battmgr.c
index 490137a..98a70e1 100644
--- a/drivers/power/supply/qcom_battmgr.c
+++ b/drivers/power/supply/qcom_battmgr.c
@@ -1690,6 +1690,14 @@ static int qcom_battmgr_probe(struct auxiliary_device *adev,
 			return dev_err_probe(dev, PTR_ERR(battmgr->wls_psy),
 					     "failed to register wireless charing power supply\n");
 	} else {
+		/*
+		 * The SM8350-class firmware has no BATTMGR_BAT_INFO request, so
+		 * @unit is never populated from the firmware. It reports charge
+		 * domain values, so set it statically here - otherwise the
+		 * CHARGE_* properties are rejected with -ENODATA.
+		 */
+		battmgr->unit = QCOM_BATTMGR_UNIT_mAh;
+
 		if (battmgr->variant == QCOM_BATTMGR_SM8550)
 			psy_desc = &sm8550_bat_psy_desc;
 		else

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

[Jan-Michael Brummer]

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);