linux: bypass charging on SM8750

projects/ROCKNIX/devices/SM8750/patches/linux/0504-ROCKNIX-charge-bypass.patch

@@ -0,0 +1,145 @@
+From 0000000000000000000000000000000000000000 Mon Sep 17 00:00:00 2001
+From: Anze <aanzdev@gmail.com>
+Date: Wed, 3 Jun 2026 19:40:00 +0200
+Subject: [PATCH] power: supply: qcom_battmgr: support charge_behaviour
+ (USB power-path bypass) on sm8550
+
+The battery management firmware on sm8550-class platforms (e.g. the AYN
+Odin 3, SM8750, which uses the sm8550 battmgr variant) can keep the system
+running from the USB input while leaving the battery untouched - neither
+charging nor discharging. The vendor (downstream qti_battery_charger)
+exposes this as the OEM USB property "usb_charge_now": writing 0 inhibits
+charging from the input (power-path bypass), 1 restores normal charging.
+
+The PMIC GLINK request for this is identical to the one qcom_battmgr
+already builds for every other property (owner BATTMGR, REQ_RESP, the
+{battery, property, value} body); only the opcode (USB_PROPERTY_SET) and
+the property id (14) differ. Expose it through the standard
+POWER_SUPPLY_PROP_CHARGE_BEHAVIOUR interface:
+
+  auto           -> usb_charge_now = 1 (normal charging)
+  inhibit-charge -> usb_charge_now = 0 (run from the adapter, battery floats)
+
+This adds /sys/class/power_supply/battery/charge_behaviour and is wired
+only into the sm8550 battery psy, so other variants are unaffected.
+
+Verified on an AYN Odin 3: with "inhibit-charge" and the charger online,
+battery status goes to Discharging / charge_type N/A with battery current
+~0, matching the behaviour of the vendor "bypass charging" toggle; "auto"
+resumes charging.
+
+Signed-off-by: Anze <aanzdev@gmail.com>
+---
+ drivers/power/supply/qcom_battmgr.c | 52 ++++++++++++++++++++++++++++
+ 1 file changed, 52 insertions(+)
+
+diff --git a/drivers/power/supply/qcom_battmgr.c b/drivers/power/supply/qcom_battmgr.c
+--- a/drivers/power/supply/qcom_battmgr.c
++++ b/drivers/power/supply/qcom_battmgr.c
+@@ -86,6 +86,13 @@
+ #define USB_ADAP_TYPE			7
+ #define USB_MOISTURE_DET_EN		8
+ #define USB_MOISTURE_DET_STS		9
++/*
++ * OEM USB property exposed by the battery management firmware on sm8550-class
++ * platforms: 1 lets the charger replenish the battery from the USB input,
++ * 0 inhibits battery charging while keeping the system powered from the input
++ * (power-path bypass). Mirrors the vendor "usb_charge_now" control.
++ */
++#define USB_CHARGE_ENABLE		14
+
+ #define BATTMGR_WLS_PROPERTY_GET	0x34
+ #define BATTMGR_WLS_PROPERTY_SET	0x35
+@@ -325,6 +332,9 @@
+
+ 	bool service_up;
+
++	/* cached POWER_SUPPLY_CHARGE_BEHAVIOUR_* value (sm8550 variant) */
++	unsigned int charge_behaviour;
++
+ 	struct qcom_battmgr_info info;
+ 	struct qcom_battmgr_status status;
+ 	struct qcom_battmgr_ac ac;
+@@ -633,6 +643,9 @@
+ 	case POWER_SUPPLY_PROP_CHARGE_CONTROL_END_THRESHOLD:
+ 		val->intval = battmgr->info.charge_ctrl_end;
+ 		break;
++	case POWER_SUPPLY_PROP_CHARGE_BEHAVIOUR:
++		val->intval = battmgr->charge_behaviour;
++		break;
+ 	case POWER_SUPPLY_PROP_MANUFACTURE_YEAR:
+ 		val->intval = battmgr->info.year;
+ 		break;
+@@ -756,12 +769,46 @@
+ 	return 0;
+ }
+
++/*
++ * Toggle whether the battery is charged from the USB input. Setting
++ * "inhibit-charge" stops charging while the system keeps running from the
++ * adapter (the battery neither charges nor discharges) - i.e. power-path
++ * bypass; "auto" restores normal charging.
++ */
++static int qcom_battmgr_set_charge_behaviour(struct qcom_battmgr *battmgr,
++					     int behaviour)
++{
++	u32 value;
++	int ret;
++
++	switch (behaviour) {
++	case POWER_SUPPLY_CHARGE_BEHAVIOUR_AUTO:
++		value = 1;
++		break;
++	case POWER_SUPPLY_CHARGE_BEHAVIOUR_INHIBIT_CHARGE:
++		value = 0;
++		break;
++	default:
++		return -EINVAL;
++	}
++
++	mutex_lock(&battmgr->lock);
++	ret = qcom_battmgr_request_property(battmgr, BATTMGR_USB_PROPERTY_SET,
++					    USB_CHARGE_ENABLE, value);
++	mutex_unlock(&battmgr->lock);
++	if (!ret)
++		battmgr->charge_behaviour = behaviour;
++
++	return ret;
++}
++
+ static int qcom_battmgr_bat_is_writeable(struct power_supply *psy,
+ 					 enum power_supply_property psp)
+ {
+ 	switch (psp) {
+ 	case POWER_SUPPLY_PROP_CHARGE_CONTROL_START_THRESHOLD:
+ 	case POWER_SUPPLY_PROP_CHARGE_CONTROL_END_THRESHOLD:
++	case POWER_SUPPLY_PROP_CHARGE_BEHAVIOUR:
+ 		return 1;
+ 	default:
+ 		return 0;
+@@ -784,6 +831,8 @@
+ 		return qcom_battmgr_set_charge_start_threshold(battmgr, pval->intval);
+ 	case POWER_SUPPLY_PROP_CHARGE_CONTROL_END_THRESHOLD:
+ 		return qcom_battmgr_set_charge_end_threshold(battmgr, pval->intval);
++	case POWER_SUPPLY_PROP_CHARGE_BEHAVIOUR:
++		return qcom_battmgr_set_charge_behaviour(battmgr, pval->intval);
+ 	default:
+ 		return -EINVAL;
+ 	}
+@@ -918,6 +967,7 @@
+ 	POWER_SUPPLY_PROP_POWER_NOW,
+ 	POWER_SUPPLY_PROP_CHARGE_CONTROL_START_THRESHOLD,
+ 	POWER_SUPPLY_PROP_CHARGE_CONTROL_END_THRESHOLD,
++	POWER_SUPPLY_PROP_CHARGE_BEHAVIOUR,
+ };
+
+ static const struct power_supply_desc sm8550_bat_psy_desc = {
+@@ -925,6 +975,8 @@
+ 	.type = POWER_SUPPLY_TYPE_BATTERY,
+ 	.properties = sm8550_bat_props,
+ 	.num_properties = ARRAY_SIZE(sm8550_bat_props),
++	.charge_behaviours = BIT(POWER_SUPPLY_CHARGE_BEHAVIOUR_AUTO) |
++			     BIT(POWER_SUPPLY_CHARGE_BEHAVIOUR_INHIBIT_CHARGE),
+ 	.get_property = qcom_battmgr_bat_get_property,
+ 	.set_property = qcom_battmgr_bat_set_property,
+ 	.property_is_writeable = qcom_battmgr_bat_is_writeable,