[PATCH] power: supply: qcom_battmgr: do not report power_now on SM8750

[Qianhui Xu]

From: Xu Qianhui <xiaqinghuan@xxxxxxxxxxxxxxxx>

The SM8750 QBG firmware fills BATT_POWER_NOW via its maximum-load updater
instead of an instantaneous measurement: the property getter indexes
context + 0x6a8 + 4 * property, so property 22 (BATT_POWER_NOW) reads the
offset written by the maximum-load path.  Exposing that as power_now makes
userspace report e.g. 89 W while the battery is charging below 1 W, or
above 100 W while discharging at about 4 W.

The SM8750 PMIC GLINK node is already described in DT
("qcom,sm8750-pmic-glink" in sm8750-mtp/qrd), but the driver has no entry
for it, so it falls back to QCOM_BATTMGR_SM8350 and advertises POWER_NOW.

Add the SM8750 variant and a battery descriptor that reuses the SM8550
properties without POWER_NOW.  The property array is reordered so that
POWER_NOW is the last entry, which keeps the new descriptor a two-line
addition; property ordering itself is not ABI.

Voltage, current, charge counters and the charge-control thresholds are
retained.

Tested on Lenovo Legion Y700 Gen4 (TB322FC, SM8750P): charging and
discharging, UPower state-of-charge and rate are unchanged and power_now
is no longer exposed.

Signed-off-by: Xu Qianhui <xiaqinghuan@xxxxxxxxxxxxxxxx>
---
 drivers/power/supply/qcom_battmgr.c | 29 +++++++++++++++++++++++++++--
 1 file changed, 27 insertions(+), 2 deletions(-)

diff --git a/drivers/power/supply/qcom_battmgr.c b/drivers/power/supply/qcom_battmgr.c
index 7716eb9e1a..dbc98ac8a7 100644
--- a/drivers/power/supply/qcom_battmgr.c
+++ b/drivers/power/supply/qcom_battmgr.c
@@ -24,6 +24,7 @@ enum qcom_battmgr_variant {
 	QCOM_BATTMGR_SC8280XP,
 	QCOM_BATTMGR_SM8350,
 	QCOM_BATTMGR_SM8550,
+	QCOM_BATTMGR_SM8750,
 	QCOM_BATTMGR_X1E80100,
 };
 
@@ -916,9 +917,13 @@ static const enum power_supply_property sm8550_bat_props[] = {
 	POWER_SUPPLY_PROP_TIME_TO_EMPTY_AVG,
 	POWER_SUPPLY_PROP_INTERNAL_RESISTANCE,
 	POWER_SUPPLY_PROP_STATE_OF_HEALTH,
-	POWER_SUPPLY_PROP_POWER_NOW,
 	POWER_SUPPLY_PROP_CHARGE_CONTROL_START_THRESHOLD,
 	POWER_SUPPLY_PROP_CHARGE_CONTROL_END_THRESHOLD,
+	/*
+	 * Kept last on purpose: SM8750 reuses this list without POWER_NOW,
+	 * see sm8750_bat_psy_desc.
+	 */
+	POWER_SUPPLY_PROP_POWER_NOW,
 };
 
 static const struct power_supply_desc sm8550_bat_psy_desc = {
@@ -931,6 +936,23 @@ static const struct power_supply_desc sm8550_bat_psy_desc = {
 	.property_is_writeable = qcom_battmgr_bat_is_writeable,
 };
 
+/*
+ * The SM8750 QBG firmware fills BATT_POWER_NOW from its maximum-load updater
+ * instead of from an instantaneous measurement, so the published value is not
+ * a present power reading (it reports the maximum load, e.g. 89 W while the
+ * battery is actually charging below 1 W).  Do not advertise POWER_NOW on
+ * this platform.
+ */
+static const struct power_supply_desc sm8750_bat_psy_desc = {
+	.name = "qcom-battmgr-bat",
+	.type = POWER_SUPPLY_TYPE_BATTERY,
+	.properties = sm8550_bat_props,
+	.num_properties = ARRAY_SIZE(sm8550_bat_props) - 1,
+	.get_property = qcom_battmgr_bat_get_property,
+	.set_property = qcom_battmgr_bat_set_property,
+	.property_is_writeable = qcom_battmgr_bat_is_writeable,
+};
+
 static int qcom_battmgr_ac_get_property(struct power_supply *psy,
 					enum power_supply_property psp,
 					union power_supply_propval *val)
@@ -1617,6 +1639,7 @@ static const struct of_device_id qcom_battmgr_of_variants[] = {
 	{ .compatible = "qcom,sc8180x-pmic-glink", .data = (void *)QCOM_BATTMGR_SC8280XP },
 	{ .compatible = "qcom,sc8280xp-pmic-glink", .data = (void *)QCOM_BATTMGR_SC8280XP },
 	{ .compatible = "qcom,sm8550-pmic-glink", .data = (void *)QCOM_BATTMGR_SM8550 },
+	{ .compatible = "qcom,sm8750-pmic-glink", .data = (void *)QCOM_BATTMGR_SM8750 },
 	{ .compatible = "qcom,x1e80100-pmic-glink", .data = (void *)QCOM_BATTMGR_X1E80100 },
 	/* Unmatched devices falls back to QCOM_BATTMGR_SM8350 */
 	{}
@@ -1690,7 +1713,9 @@ 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 {
-		if (battmgr->variant == QCOM_BATTMGR_SM8550)
+		if (battmgr->variant == QCOM_BATTMGR_SM8750)
+			psy_desc = &sm8750_bat_psy_desc;
+		else if (battmgr->variant == QCOM_BATTMGR_SM8550)
 			psy_desc = &sm8550_bat_psy_desc;
 		else
 			psy_desc = &sm8350_bat_psy_desc;
-- 
2.53.0